JP6338142B2 - Chisel - Google Patents

Description

  The present invention relates to a chisel for applying a striking force to a striking object.

  A chisel is known as a tool for hitting and crushing a hitting object such as a concrete structure. This type of chisel is attached to the tip of an arm of a hydraulic breaker, etc., and reciprocates in a direction perpendicular to the object to be pulverized, and applies an impact force to the object to be pulverized to pulverize the object to be struck. However, a large noise is generated during the crushing operation, so that not only is it easy for people on the job site to feel stress, but also causes noise problems when there is a house nearby.

  In view of such a situation, a chisel in which a weight member is attached to a predetermined portion of the chisel body has been proposed so far (see, for example, Patent Documents 1 to 3). Thereby, it is supposed that the sound quality of the noise emitted from the chisel can be changed to something that is not unpleasant for humans. However, in the chisel of Patent Documents 1 to 3, the weight member is firmly fixed without moving relative to the chisel body (for example, paragraphs 0029 of Patent Document 1 and Patent Document 2). (See Paragraph 0028 and Paragraph 0031 of Patent Document 3). Even though the sound quality of the sound emitted from the chisel can be changed, the noise level of the sound emitted from the chisel is not reduced (for example, Patent Document 1). , Paragraph 0039 of Patent Document 2, and paragraph 0039 of Patent Document 3), and the noise prevention effect is also considered to be limited.

  In addition, there has been proposed a chisel in which the outer peripheral surface of the chisel body is covered with a cylindrical chisel cover and the outer peripheral surface of the chisel body and the inner peripheral surface of the chisel cover are separated via a gap (for example, Patent Documents). 4). Thereby, it is said that the noise generated from the chisel body can be attenuated by the air layer in the gap between the outer peripheral surface of the chisel body and the inner peripheral surface of the chisel cover (see, for example, paragraph 0020 of Patent Document 4). reference.). However, in the chisel of Patent Document 4, in order to attenuate the sound emitted from the chisel body as much as possible, it is necessary to cover the entire chisel body with a chisel cover. Usually, the tip of the chisel body strikes an object to be hit. It is a part for, and it is necessary to keep open. For this reason, there exists a possibility that a sound may leak from the open | released part. In addition, if the chisel cover is covered with the chisel cover up to a portion close to the tip of the chisel body, the chisel cover may come into contact with the hit object and become a new noise source. In the first place, the noise attenuation effect by the air layer is very limited, and it is considered difficult to significantly reduce the noise with the chisel of Patent Document 4.

JP 2007-237369 A JP 2007-237370 A JP 2007-237371 A JP 2007-326198 A

  The present invention has been made in order to solve the above-described problems, and provides a chisel that can significantly reduce the noise level of sound emitted when hitting a hitting object.

  The above problem consists of a chisel body that crushes a hitting object by applying a striking force at its tip, and a chisel vibrator incorporated in the chisel body in a state in which longitudinal vibration is possible relative to the chisel body. This is solved by providing a chisel characterized in that the chisel vibrator vibrates longitudinally in accordance with the vibration generated in the chisel body when hitting a hitting object, thereby reducing the noise generated therefrom. Here, “longitudinal vibration” refers to vibration in a direction parallel to the center line of the chisel body. On the other hand, the vibration in the direction perpendicular to the center line of the chisel body (the radial direction of the chisel body) is called “lateral vibration”.

  In this way, by incorporating a chisel vibrating body that performs longitudinal vibration relative to the chisel body, resonance in the longitudinal vibration mode of the chisel body is suppressed, and the most frequently occurring immediately after the chisel body is subjected to striking force. The noise level of an unpleasant sound (hereinafter sometimes referred to as “initial sound”) can be greatly reduced. The initial sound is mainly determined by the resonance of the longitudinal vibration mode (primary longitudinal vibration mode) of the chisel body, and if the resonance of this longitudinal vibration mode is suppressed, the noise level of the initial sound can be greatly reduced. Was confirmed by the experimental results of Experiments 1 and 2 described later and the results of Simulation 1. On the other hand, the principle that the longitudinal vibration mode of the chisel body is suppressed by the longitudinal vibration of the chisel vibrator is not clear at this time, but the chisel body and the chisel vibrator vibrate relatively. It is presumed that a frictional force is generated at the boundary, and the frictional force is applied in a direction and timing that suppresses the resonance of the chisel body.

  By the way, the chisel vibrating body is expressed as “possible to vibrate longitudinally relative to the chisel main body”. However, when the chisel according to the present invention is actually manufactured, the chisel vibrating body is slightly attached to the chisel main body. In contrast, lateral vibration is also performed. For example, when an annular chisel vibrating body is externally fitted in a state in which longitudinal vibration is possible relative to the outer periphery of a cylindrical chisel body, the outer diameter of the chisel body and the chisel vibrating body are manufactured for manufacturing reasons. The inner diameter of the chisel vibrating body cannot be completely matched with the inner diameter of the chisel, and the inner diameter of the chisel vibrating body is set to a dimension having a margin more than the outer diameter of the chisel main body. That is, a gap is always formed between the outer peripheral surface of the chisel body and the inner peripheral surface of the chisel vibrating body. This gap allows the chisel vibrator to undergo lateral vibration. By this lateral vibration of the chisel vibrator, resonance in the transverse vibration mode of the chisel body can be reduced, and reverberation sound generated when the chisel body applies striking force can also be reduced. The reverberation sound is mainly determined by the resonance of the transverse vibration mode of the chisel body, and if the resonance of the transverse vibration mode is suppressed, the reverberation sound can be greatly reduced. The result and the result of simulation 1 were confirmed. On the other hand, it is presumed that the principle of suppressing the vibration of the chisel body in the transverse vibration mode by the transverse vibration of the chisel vibrating body is the same as in the case of the resonance in the longitudinal vibration mode.

  In the chisel of the present invention, the chisel vibrator may be incorporated directly into the chisel body. However, when the chisel vibrating body is in direct contact with the chisel main body in this way, the chisel vibration occurs when the chisel vibrating body vibrates longitudinally or laterally due to the impact when the hitting force is applied to the chisel main body. When the body collides with the chisel body, a secondary impact force is applied to the chisel body, and the secondary impact force may reduce the effect of suppressing the resonance of the chisel body. For this reason, it is preferable to arrange a buffer body made of an elastic material, a viscous material, or a viscoelastic material in a gap between the chisel body and the chisel vibrating body. As a result, the secondary striking force applied to the chisel body can be relaxed, and the reduction in the suppression effect of the resonance of the longitudinal vibration mode of the chisel due to the secondary striking force can be prevented. In addition to the effect of reducing the secondary impact force, when the chisel vibrating body vibrates relative to the chisel body, the shock absorber inserted therebetween undergoes compression deformation or shear deformation, and this There is also an effect of suppressing the resonance of the chisel body by a damping action that sometimes occurs inside the material. Due to this damping action, it is possible to further suppress noise emitted from the chisel.

In the chisel of the present invention, the masses of the chisel body and the chisel vibrator vary depending on the dimensions of the chisel and are not particularly limited. However, if the ratio M ₂ / M ₁ of the mass M ₂ of the chisel vibrating body to the mass M ₁ of the chisel main body is too small (the chisel vibrating body is too light), the inertia of the chisel vibrating body that performs longitudinal vibration with respect to the chisel main body. By reducing the force, the resonance suppressing action due to the frictional force is also relatively reduced, and the effect of suppressing the resonance of the chisel body may be limited. For this reason, it is preferable that the ratio M ₂ / M ₁ (when a plurality of chisel vibrators are incorporated in the chisel body, the total mass thereof is the same hereinafter) is 0.01 or more. On the other hand, if the ratio M ₂ / M ₁ is too large (the chisel vibrating body is too heavy), the weight balance as the chisel may be deteriorated. For this reason, the ratio M ₂ / M ₁ is preferably 0.5 or less.

In the chisel of the present invention, the total length L ₁ (the length in the direction parallel to the center line of the chisel main body; the same applies hereinafter) of the chisel main body and the chisel vibrating body varies depending on the use of the chisel and is not particularly limited. However, if the ratio L ₂ / L ₁ of the overall length L ₂ of the chisel vibrator to the overall length L ₁ of the chisel body is too small (the chisel vibrator is too short), the following problems may occur. That is, as can be seen from the experimental results of Experiments 1 and 2 described later and the result of Simulation 1, the initial sound when the impact force is applied to the chisel body is most affected by the resonance of the primary longitudinal vibration mode. However, the influence of resonance in other vibration modes (lateral vibration mode and secondary and higher longitudinal vibration modes) is also great. In addition, in order to suppress the resonance of a specific vibration mode of the chisel body as efficiently as possible, the chisel vibration body is arranged at a location where the amplitude of the resonance of the specific vibration mode in the chisel body is as large as possible. It is considered good. However, as shown in FIG. 26, the location where the amplitude in the chisel body is maximum differs depending on the vibration mode. FIG. 26 is a graph theoretically obtained from the relationship between the amplitude of each vibration mode in the chisel body and the position in the chisel body. “L _X / L ₁ ” on the horizontal axis of the graph of FIG. 26 means the ratio L _X / L ₁ of the distance L _X from the tip of the chisel body to the target point with respect to the total length L ₁ of the chisel body. Specifically, the ratio L _X / L ₁ being “0” means the tip of the chisel body, and the ratio L _X / L ₁ being “0.5” is that the chisel body The ratio L _X / L ₁ of “1” means that it is the base end of the chisel body. Thus, since portions having the maximum amplitude is different by the vibration mode, when the total length L ₂ of the chisel vibrator is short, it is difficult to place the chisel vibrator as the resonance of the plurality of vibration modes can be effectively suppressed In addition, high accuracy is required for the mounting position of the chisel vibrator on the chisel body. For this reason, the ratio L ₂ / L ₁ (when a plurality of chisel vibrators are incorporated into the chisel main body, the total length thereof is the same unless otherwise specified) is 0.05 or more. preferable. On the other hand, if the ratio L ₂ / L ₁ is too large (the chisel vibrating body is too long), not only is it difficult to secure a hitting location or the like in the chisel body, but the mass of the chisel vibrating body inevitably increases. There is also a possibility that the weight balance as will become worse. For this reason, the ratio L ₂ / L ₁ is preferably 0.5 or less.

In the chisel of the present invention, the specific location for incorporating the chisel vibrator is not particularly limited, but the ratio of the distance L ₃ from the tip of the chisel body to the center of the chisel vibrator (vibration center) with respect to the total length L ₁ of the chisel body. It is preferable to incorporate a chisel vibrator at a position where L ₃ / L ₁ is 0 to 0.4 or 0.6 to ₁ . In other words, it is preferable to incorporate the chisel vibrator in a section other than the central section of the chisel body. The reason is as follows. That is, as described above, the most disturbing thing that occurs when the chisel body applies striking force is the initial sound, and this initial sound can be reduced by suppressing the resonance of the primary longitudinal vibration mode of the chisel body. . In addition, when the resonance of the specific vibration mode (here, the primary longitudinal vibration mode) of the chisel body is to be suppressed as efficiently as possible, the amplitude of the resonance of the specific vibration mode of the chisel body can be as small as possible. What is necessary is just to arrange | position a chisel vibrating body in the location which becomes large. In this regard, referring to FIG. 26 described above, the amplitude of the primary longitudinal vibration mode is maximum at both ends (tip and base ends) of the chisel body, and is minimum (zero) at the center of the chisel body. ing. From this, it can be seen that in order to suppress the generation of the initial sound, it is preferable that the chisel vibrating body is disposed not in the vicinity of the center portion of the chisel body but in the vicinity of both end portions. A section in which the amplitude (absolute value) of the primary longitudinal vibration mode is 30% or more of the maximum value is a section in which the resonance of the primary longitudinal vibration mode can be effectively suppressed, and the section is read from FIG. In general, the ratio L ₃ / L ₁ is a section of 0.4 or less and a section of 0.6 or more. In this section, since the amplitude is large in many vibration modes other than the primary longitudinal vibration mode, incorporating the chisel vibrator in this section is also effective from the viewpoint of reducing reverberant sound.

  In the chisel of the present invention, the specific structure (incorporation structure) for incorporating the chisel vibrating body into the chisel body is not particularly limited, but for example, the following two types are conceivable. First, the chisel vibrating body is attached to the outer peripheral portion of the chisel body. Examples of this built-in structure include a structure in which an annular chisel vibrating body is fitted around the outer periphery of the chisel body, and a vertical direction (a direction parallel to the center line of the chisel body) provided on the outer peripheral surface of the chisel body. For example, a structure in which a chisel vibrator is fitted into the fitting groove may be used. Second, the chisel vibrating body is housed inside the chisel body. As an example of this built-in structure, there is a structure in which the chisel vibrating body is accommodated in a cavity provided in the longitudinal direction (direction parallel to the center line of the chisel body) inside the chisel vibrating body. When incorporating a plurality of chisel vibrators per chisel body, a plurality of built-in structures can be employed.

  As described above, according to the present invention, it is possible to provide a chisel that can greatly reduce the noise level of the sound emitted therefrom.

It is the perspective view which showed the state which assembled the chisel of the first embodiment. It is the perspective view which showed the state which decomposed | disassembled the chisel of 1st embodiment. It is sectional drawing which showed the state which cut | disconnected the chisel of 1st embodiment by the plane containing the centerline. In the chisel of the first embodiment, it is a cross-sectional view showing a state in which the resonance of the primary longitudinal vibration mode of the chisel body is suppressed by the longitudinal vibration of the chisel vibrating body. In the chisel of the first embodiment, it is a cross-sectional view showing a state in which the lateral vibration mode resonance of the chisel body is suppressed by the lateral vibration of the chisel vibrating body. It is the perspective view which showed the chisel of the 2nd embodiment. It is sectional drawing which showed the state which cut | disconnected the chisel of the 2nd embodiment by the plane containing the centerline. It is the perspective view which showed the chisel of the 3rd embodiment. It is sectional drawing which showed the state which cut | disconnected the chisel of 3rd embodiment by the plane containing the centerline. It is the perspective view which showed the chisel of the 4th embodiment. It is sectional drawing which showed the state which cut | disconnected the chisel of 4th embodiment by the plane perpendicular | vertical to the centerline. It is the perspective view which showed the chisel of 5th embodiment. It is sectional drawing which showed the state which cut | disconnected the chisel of 5th embodiment by the plane containing the centerline. It is the perspective view which showed the state which cut | disconnected the chisel of the 6th embodiment by the plane containing the centerline. It is sectional drawing which showed the state which cut | disconnected the chisel of 6th embodiment by the plane perpendicular | vertical to the centerline. FIG. 6 is a diagram showing an outline of Experiment 1. 6 is a graph showing a frequency analysis result of a measurement sound in Experiment 1. 6 is a graph showing a time change of a noise level of a measurement sound in Experiment 1. It is the graph which showed the relationship between the frequency of the measurement sound in Experiment 1, the time (time) when the frequency was detected, and the noise level. FIG. 6 is a diagram showing an outline of Experiment 2. 6 is a graph showing analysis results of vibration modes in Experiment 2. It is the figure which showed the mode analysis result by the finite element method in the simulation. In Experiment 3, it is the graph which showed the frequency analysis result of the sound emitted from the chisel of Example 1. In Experiment 3, it is the graph which showed the frequency analysis result of the sound emitted from the chisel of Example 2. In Experiment 3, it is the graph which showed the frequency analysis result of the sound emitted from the chisel of the comparative example 1. It is the graph which calculated | required theoretically and showed the relationship between the amplitude of each vibration mode in a chisel main body, and the position in a chisel main body.

  A preferred embodiment of the chisel according to the present invention will be described more specifically with reference to the drawings. In the following, the chisel according to the present invention will be described by taking six embodiments (first to sixth embodiments) as examples.

[Chisel of the first embodiment]
FIG. 1 is a perspective view showing a state in which the chisel of the first embodiment is assembled. FIG. 2 is a perspective view showing a state in which the chisel of the first embodiment is disassembled. FIG. 3 is a cross-sectional view showing a state in which the chisel of the first embodiment is cut along a plane including the center line L thereof. FIG. 4 is a cross-sectional view showing a state in which resonance in the longitudinal vibration mode of the chisel body 10 is suppressed by longitudinal vibration of the chisel vibrator 20 in the chisel of the first embodiment. FIG. 5 is a cross-sectional view showing a state in which the resonance of the chisel main body 10 in the transverse vibration mode is suppressed by the transverse vibration of the chisel vibrating body 20 in the chisel of the first embodiment. As shown in FIGS. 1 to 3, the chisel of the first embodiment includes a chisel body 10, a chisel vibrating body 20, and a buffer body 30. Hereinafter, each part which comprises the chisel of a 1st embodiment is demonstrated in detail.

Chisel body The chisel body 10 is for crushing the hitting object by applying a hitting force to the hitting object at its tip. The shape and dimensions of the chisel body 10 are not particularly limited as long as a striking force can be applied to the striking object. For example, the chisel body 10 is not limited to a circular shape in cross section perpendicular to the center line L, and may be in other shapes such as a polygon such as a hexagon or an ellipse. In chisel first embodiment, the chisel body 10, in its entire length L ₁ is 500 mm, its has an outer diameter D ₁ is in a substantially cylindrical body of 51 mm, the tip side, to form a sharp conical Yes. On the other hand, on the base end side of the chisel body 10, grooves and bolt holes (not shown) are formed so that the chisel body 10 can be fixed to a holder or the like provided at the arm tip of the hydraulic breaker. The chisel body 10 is reciprocated in the direction of the center line L by a driving force from a hydraulic driving device (chisel driving means) provided in the hydraulic breaker. The chisel body 10 is usually formed using a metal such as stainless steel or iron.

  In the chisel of the first embodiment, a fitting groove 10 a for fitting the chisel vibrating body 20 is provided in an annular shape along the circumferential direction of the chisel main body 10 in the outer peripheral portion of the chisel main body 10. The chisel vibrating body 20 performs longitudinal vibration while being fitted in the fitting groove 10a. The fitting groove 10 a may be provided in a state (open ring shape) divided in a part of the entire circumferential section of the outer peripheral portion of the chisel body 10. However, in this case, if the shape of the chisel body 10 or the chisel vibrating body 20 does not have rotational symmetry about the center line L, a great disadvantage arises from the viewpoint of suppressing resonance in the longitudinal vibration mode. Although it is considered that there is no possibility of the lateral vibration, the suppression effect varies depending on the direction in which the chisel vibrator 20 vibrates, which may adversely affect the suppression of resonance in the lateral vibration mode of the chisel body 10. For this reason, it is preferable that the fitting groove 10 a is provided over the entire peripheral section of the outer peripheral portion of the chisel body 10.

The width W _{1 of the} fitting groove 10 a (the width in the direction parallel to the center line L of the chisel body 10) can allow longitudinal vibration of the chisel vibrator 20 (larger than the total length L ₂ of the chisel vibrator 20). If it does not specifically limit. However, if the ratio W ₁ / L ₂ of the width W of the fitting groove 10a to the entire length L ₂ of the chisel vibrating body 20 is too small, the amplitude of the vertical vibration of the chisel vibrating body 20 becomes small, and the longitudinal vibration mode of the chisel main body 10 is reduced. There is a possibility that the effect of suppressing the resonance of the above becomes limited. For this reason, the ratio W ₁ / L ₂ is preferably 1.01 or more. The ratio W ₁ / L ₂ is more preferably 1.02 or more, and further preferably 1.03 or more. When a plurality of chisel vibrators 20 are incorporated into the chisel body 10, the ratio corresponding to the ratio W ₁ / L ₂ for each chisel vibrator 20 and the fitting groove 10 a satisfies the above relationship. Good.

On the other hand, if the ratio W ₁ / L ₂ of the width W ₁ of the fitting groove 10 a to the entire length L ₂ of the chisel vibrating body 20 is excessively increased, the chisel vibrating body 20 is only in a part of the section in the width direction of the fitting groove 10 a. From the viewpoint of suppressing the resonance of the longitudinal vibration mode of the chisel body 10 (usually the section on the lower side in the vertical direction) longitudinally vibrates. For this reason, the ratio W ₁ / L ₂ is preferably 5 or less, more preferably 3 or less, and even more preferably 2 or less. If between the front end surface and the proximal surfaces of the pair of wall surfaces and chisel vibrating body 20 Hamakomimizo 10a not provided a cushion 30, a ratio W _{1 /} L ₂ is preferably suppressed to 1.5 or less . When a plurality of chisel vibrators 20 are incorporated into the chisel body 10, the ratio corresponding to the ratio W ₁ / L ₂ for each chisel vibrator 20 and the fitting groove 10 a satisfies the above relationship. Good. In the chisel of the first embodiment, the width W _{1 of the} fitting groove 10a is 50 mm, the total length L ₂ of the chisel vibrating body 20 is 48 mm, and the ratio W ₁ / L ₂ is about 1.042. ing.

  By the way, in the chisel of the first embodiment in which the fitting groove 10a is provided in an annular shape, the chisel body 10 may be entirely formed of one member, but in this case, the chisel vibrator Unless the structure 20 can be divided, the chisel vibrator 20 cannot be fitted into the fitting groove 10a. For this reason, in the chisel of the first embodiment, as shown in FIG. 2, the chisel body 10 includes a first member 11 that forms the distal end side of the chisel body 10, and a first end that forms the proximal end side of the chisel body 10. The structure is separable into two members 12 and a connecting member 13 for connecting and fixing the first member 11 and the second member 13.

Chisel vibrating body The chisel vibrating body 20 is in a state of being fitted into the fitting groove 10 a of the chisel body 10. The chisel vibrating body 20 is generated in the chisel body 10 by longitudinal vibration relative to the chisel body 10 as shown in FIG. 4 when the chisel body 10 applies a striking force to the hit object. While suppressing the resonance of the longitudinal vibration mode, as shown in FIG. 5, the vibration of the transverse vibration mode generated in the chisel body 10 is suppressed by performing a lateral vibration relative to the chisel body 10. .

  The shape of the chisel vibrating body 20 is not particularly limited, but in the chisel of the first embodiment, it is cylindrical (annular). The chisel vibrating body 20 is entirely formed by one member, but may have a structure that can be divided into a plurality of members. As a result, as shown in FIG. 2, it is possible to attach the chisel vibrating body 20 and the buffer body 30 to the chisel body 10 without making the chisel body 10 separable. Therefore, for example, even if the buffer body 30 is damaged, it can be easily replaced.

  The material of the chisel vibrating body 20 is not particularly limited as long as it has a certain degree of rigidity (formality). However, if the chisel vibrating body 20 is made of a material having a certain density, the weight can be secured even if the chisel vibrating body 20 is made compact, and the chisel body 10 applies a striking force to the striking object. In addition, a large inertial force is generated by the chisel vibrator 20. That is, according to the vibration of the chisel body 10, the chisel vibrating body 20 is relatively easy to perform longitudinal vibration and lateral vibration. For this reason, it is preferable to form the chisel vibrating body 20 with a metal such as stainless steel or iron.

Mass _{M 2} of the chisel vibrator 20, as the ratio _M 2 / _{M 1} of the mass _{M 2} of the chisel vibrator 20 to the mass _{M 1} of the chisel body 10 is in the range of 0.01 to 0.5 already mentioned Such a setting is preferable. However, in order to further enhance the effect of suppressing resonance in the longitudinal vibration mode and the transverse vibration mode of the chisel body 10, the ratio M ₂ / M ₁ is more preferably 0.03 or more, and further preferably 0.05 or more. . On the other hand, considering the weight balance of the chisel, the ratio M ₂ / M ₁ is more preferably 0.3 or less, and further preferably 0.1 or less. In the chisel of the first embodiment, the mass M ₁ of the chisel body 10 is 7340 g, the mass M ₂ of the chisel vibrating body 20 is 575 g, and the ratio M ₂ / M ₁ is about 0.0783. .

Overall length _{L 2} of the chisel vibrator, as already mentioned, the ratio _L 2 / _{L 1} of the total length _{L 1} of the chisel body preferably set in a range of 0.05 to 0.5. However, considering that it is possible to suppress resonance of a larger number of vibration modes that can occur in the chisel body 10, the ratio L ₂ / L ₁ is more preferably 0.06 or more, and 0.07 or more. Further preferred. On the other hand, considering the weight balance of the chisel, the ratio L ₂ / L ₁ is more preferably 0.4 or less, and further preferably 0.3 or less. In the chisel first embodiment, in the total length _{L 1} of the chisel body 10 500 meters, the total length _{L 2} of the chisel vibrating body 20 has a 48 mm, the ratio _L 2 / _{L 1} is in a 0.096 .

The inner diameter of the chisel vibrating body 20 d ₁ is not particularly limited as long as the outer diameter D ₂ or more locations Hamakomimizo 10a is provided in the chisel body 10. However, when the inner diameter d ₁ of the chisel vibrating body 20 is completely matched with the outer diameter D ₂ , a slight dimensional error generated between the chisel main body 10 and the chisel vibrating body 20 causes the chisel main body 10 to have a chisel vibrating body. 20 cannot be incorporated, and it becomes difficult to dispose a buffer body between the outer peripheral surface of the chisel body 10 and the inner peripheral surface of the chisel vibrator 20. Even if it is possible to incorporate the chisel vibrating body 20 into the chisel body 10, the outer peripheral surface of the chisel body 10 and the inner peripheral surface of the chisel vibrating body 20 are too tightly adhered, and the chisel vibrating body 20. May not be able to vibrate longitudinally and laterally relative to the chisel body 10.

For this reason, it is preferable that the inner diameter d ₁ of the chisel vibrating body 20 is set to be slightly larger than the outer diameter D ₂ of the chisel body 10 where the fitting groove 10 a is provided. In terms of sensation, the chisel vibrator 20 can be smoothly slid relative to the chisel body 10 in the vertical direction (direction parallel to the center line L of the chisel body 10) by the force of a human hand. to the extent possible, the inner diameter d ₁ is set larger than the outer diameter D ₂ preferably. Specifically, the ratio _d 1 / _{D 2} of the inner diameter _{d 1} to the outer diameter _{D 2} is to set the inner diameter _{d 1} such that 1.0005 more preferable.

On the other hand, if the inner diameter d ₁ of the chisel vibrating body 20 is too large, the wobbling in the lateral direction of the chisel vibrating body 20 (direction perpendicular to the center line L of the chisel main body 10) increases. The secondary impact force in the lateral direction is easily applied to the chisel body 10. Therefore, the inner diameter d ₁ of the chisel vibrator 20 is reminded that not too larger than the outer diameter D ₂ of a portion Hamakomimizo 10a is provided in the chisel body 10. Specifically, the ratio _d 1 / _{D 2} of the inner diameter _{d 1} to the outer diameter _{D 2} is to set the inner diameter _{d 1} such that 1.05 or less preferred. When the buffer body 30 is not disposed between the outer peripheral surface of the chisel body 10 and the inner peripheral surface of the chisel vibrating body 20, the ratio d ₁ / D ₂ is preferably suppressed to 1.01 or less.

As described above, in the chisel vibrating body 20, the ratio L ₃ / L ₁ of the distance L ₃ from the tip of the chisel body 10 to the vibration center of the chisel vibrating body 20 with respect to the total length L ₁ of the chisel body 10 is 0 to 0.4. Or it is preferable to incorporate in the position which becomes 0.6-1. Thereby, the suppression effect of the initial sound and the reverberation sound when the chisel body 10 applies the striking force can be enhanced. However, when the chisel vibrating body 20 is incorporated so as to protrude from the front end or the base end of the chisel body 10, the protruding portion is hardly effective in suppressing the reverberant sound, and the chisel is hydraulically operated when hitting the hit object. The chisel vibrating body 20 is preferably attached so as not to protrude from the tip or base end of the chisel body 10 because it may interfere with the attachment to the holder at the tip of the breaker arm. Specifically, L ₃ / L ₁ becomes L ₂ / 2L _{1 to} 0.4 or 0.6 to ₁ −L ₂ / 2L ₁ when the total length L ₂ of the chisel vibrating body 20 is used. It is preferable to incorporate it into the position. The chisel vibrator 20 is more preferably incorporated at a position where the ratio L ₃ / L ₁ is L ₂ / 2L _{1 to} 0.3 or 0.7 to ₁ −L ₂ / 2L ₁ . However, if the chisel vibrating body 20 is incorporated in the tip end side of the chisel main body 10, the chisel vibrating body 20 tends to obstruct the hitting of the hit object. In addition, when the chisel is to be used by being attached to the holder at the tip of the arm of the hydraulic breaker, the chisel vibrating body 20 is incorporated at a position where the chisel body 10 is not exposed (placed within the holder). On the other hand, it is possible to prevent the chisel vibrator 20 from being damaged by the scattered objects from the hit object. For this reason, it is more preferable that the chisel vibrating body 20 is incorporated at a position where the ratio L ₃ / L ₁ is 0.7 to ₁ −L ₂ / 2L ₁ . In the chisel of the first embodiment, the chisel vibrating body 20 is incorporated at a position where the ratio L ₃ / L ₁ is 0.75.

-Buffer body The buffer body 30 applied the striking force to the hit object by preventing the chisel vibrator 20 that vibrates relative to the chisel body 10 from colliding with the chisel body 10 violently. In this case, a large secondary impact force is not applied from the chisel vibrating body 20 to the chisel body 10. In the chisel of the first embodiment, a pair of ring-shaped buffer bodies 30 are provided on the distal end side and the proximal end side of the chisel vibrating body 20. The buffer body 30 may be provided on the bottom surface of the fitting groove 10a (the gap between the outer peripheral surface of the chisel body 10 and the inner peripheral surface of the chisel vibrating body 20).

  The buffer body 30 is formed of an elastic material, a viscous material, or a viscoelastic material. The elastic material, viscous material, or viscoelastic material forming the buffer body 30 has a solid form such as an elastomer such as natural rubber, synthetic rubber, urethane rubber, silicone rubber, or fluoro rubber, or a resin such as epoxy resin. In addition to the above, there are liquids with high viscosity such as oils and aqueous solutions to which thickeners are added. However, when the buffer body 30 is exposed on the outer surface of the chisel body 10 as in the chisel of the first embodiment, the buffer body 30 may leak out if the liquid buffer body 30 is used. For this reason, when the buffer body 30 is exposed on the outer surface of the chisel body 10, it is preferable to use a solid buffer body 30. In the chisel of the first embodiment, a rubber sheet formed in a ring shape is used as the buffer body 30.

Application The chisel according to the first embodiment described above can be used as various types of chisel. In particular, it can be suitably used as a chisel for a hydraulic breaker to be mounted on a hydraulic breaker. This is because the chisel for a hydraulic breaker generates a large amount of noise and often causes noise problems, and therefore it is highly significant to adopt the configuration of the present invention.

[Chisel of the second embodiment]
FIG. 6 is a perspective view showing the chisel of the second embodiment. FIG. 7 is a cross-sectional view showing a state in which the chisel of the second embodiment is cut along a plane including the center line L thereof. In the chisel of the first embodiment described above, one chisel vibrating body 20 is incorporated into the chisel body 10. However, in the chisel of the second embodiment, three chisel vibrating bodies are mounted on the chisel body 10. 20 are incorporated in a state in which longitudinal vibration and lateral vibration are possible. Each of the chisel vibrators 20 has an annular shape. As described above, when the resonance of the specific vibration mode of the chisel body 10 is to be efficiently suppressed, the chisel vibration body 20 is placed at a position where the amplitude becomes as large as possible by the resonance of the specific vibration mode in the chisel body 10. However, by incorporating a plurality of chisel vibrators 20 into the chisel body 10 in this way, it is possible to efficiently suppress resonance in a larger number of vibration modes. About the other structure in the chisel of 2nd embodiment, since the structure substantially the same as the structure described in the chisel of 1st embodiment can be employ | adopted, description is omitted.

[Chisel of the third embodiment]
FIG. 8 is a perspective view showing the chisel of the third embodiment. FIG. 9 is a cross-sectional view showing a state in which the chisel of the third embodiment is cut along a plane including the center line L thereof. In the chisel according to the first embodiment described above, the annular chisel vibrating body 20 is fitted into the fitting groove 10a that is annularly provided at the outer peripheral portion of the chisel body 10. However, in the chisel according to the third embodiment, the chisel is The annular chisel vibrating body 20 is attached in a state capable of longitudinal vibration and lateral vibration without providing a fitting groove in the main body 10. The chisel vibrator 20 is held in the chisel body 10 by a buffer body 30 made of rubber or the like. In the chisel according to the third embodiment, although the buffer body 30 is required to have high strength, the secondary impact force in the vertical direction due to the longitudinal vibration of the chisel vibrating body 20 can be suppressed almost completely. It is. About the other structure in the chisel of 3rd embodiment, since the structure substantially the same as the structure described in the chisel of 1st embodiment can be employ | adopted, description is omitted.

[Chisel of the fourth embodiment]
FIG. 10 is a perspective view showing the chisel of the fourth embodiment. FIG. 11 is a cross-sectional view showing a state in which the chisel of the fourth embodiment is cut along a plane perpendicular to the center line L thereof. In the chisel of the first embodiment described above, the chisel vibrating body 20 is annular, but in the chisel of the fourth embodiment, three non-annular chisel vibrating bodies 20 are used. Each chisel vibrating body 20 may be disposed at a position that does not have rotational symmetry with respect to the center line L of the chisel body 10. It is arranged in the position. These chisel vibrators 20 can vibrate longitudinally and transversely relative to the chisel body 10. A fitting groove 10 b having a rectangular opening is provided at a location where the chisel vibrating body 20 is incorporated in the outer peripheral portion of the chisel body 10. About the other structure in the chisel of a 4th embodiment, since the structure substantially the same as the structure described in the chisel of a 1st embodiment can be employ | adopted, description is omitted.

[Chisel of the fifth embodiment]
FIG. 12 is a perspective view showing the chisel of the fifth embodiment. FIG. 13 is a cross-sectional view showing a state in which the chisel of the fifth embodiment is cut along a plane including the center line L thereof. In the chisel of the first embodiment described above, the chisel vibrating body 20 is fitted in the fitting groove 10a provided on the outer peripheral portion of the chisel body 10. However, in the chisel of the fifth embodiment, the chisel body 10 is centered on the center line L. The chisel vibrating body 20 is inserted into a through hole 10c provided in a direction perpendicular to the chisel, and the chisel vibrating body 20 penetrates the chisel body 10 in the lateral direction. The chisel vibrating body 20 is capable of longitudinal vibration and lateral vibration inside the through hole 10c. The chisel of the fifth embodiment is easy to ensure a large amplitude in the lateral direction of the chisel vibrating body 20, and can be suitably used when resonance in the lateral vibration mode of the chisel body 10 becomes a problem. About the other structure in the chisel of 5th embodiment, since the structure substantially the same as the structure described in the chisel of 1st embodiment can be employ | adopted, description is omitted.

[Chisel of the sixth embodiment]
FIG. 14 is a perspective view showing a state in which the chisel of the sixth embodiment is cut along a plane including the center line L thereof. FIG. 15 is a cross-sectional view showing a state in which the chisel of the sixth embodiment is cut along a plane perpendicular to the center line L thereof. In the chisel according to the first embodiment described above, the chisel vibrating body 20 is incorporated in the outer peripheral portion of the chisel body 10. However, in the chisel according to the sixth embodiment, the chisel vibrating body is provided in the hollow portion 10 d provided inside the chisel body 10. 20 is accommodated. The chisel vibrating body 20 can be longitudinally and transversely oscillated inside the cavity 10d. A buffer body 30 is filled in a gap between the outer surface of the chisel vibrating body 20 and the inner surface of the hollow portion 10d. In the chisel of the sixth embodiment, since the buffer body 30 is not exposed to the outside, a liquid material such as oil can be used as the buffer body 30. Further, in the chisel of the sixth embodiment, the chisel vibrating body 20 is also not exposed to the outside, so that not only the appearance of the chisel is simplified, but also the chisel vibrating body 20 strikes the chisel body 10. There is an advantage that it is not obstructed by mounting and is not damaged by scattered objects from the hit object. About the other structure in the chisel of 6th embodiment, since the structure substantially the same as the structure described in the chisel of 1st embodiment can be employ | adopted, description is omitted.

[Others]
In the above, the chisel according to the present invention has been described by taking the six embodiments from the first embodiment to the sixth embodiment as examples. However, the present invention is not limited to these embodiments. For example, among the configurations described in the chisel of the six embodiments described above, the configurations according to the chisel of a plurality of embodiments can be simultaneously employed. The chisel according to the present invention can be modified as appropriate without departing from the spirit of the chisel.

[Experiment]
In developing the chisel according to the present invention, or in order to investigate the effect of the chisel according to the present invention, the following experiments 1 to 3 and simulation 1 were performed.

[Experiment 1]
-Experiment method of experiment 1 First, experiment 1 was implemented in order to identify the cause of the noise emitted from a chisel when hitting a hitting object with a conventional chisel. Specifically, as shown in FIG. 16, the sound emitted when a hard sphere collides vertically with the base end surface of a chisel suspended in an anechoic chamber is measured with a microphone, and the measured sound is analyzed. did. FIG. 16 is a diagram showing an outline of Experiment 1. The chisel was hung horizontally by a stainless steel wire hung near the tip and the base. The hard sphere is suspended with a 515 mm long string, lifted to a height of 100 mm from the striking point with the string not slackened, and gently dropped from that point, perpendicular to the base end surface of the chisel. I tried to collide. The diameter of the hard sphere was 30 mm and the mass was 173.58 g. The microphone was installed at a position 1 m in the horizontal direction from the side surface of the chisel (the outer peripheral surface facing in the horizontal direction). The measured sound is analyzed with the dynamic characteristic Fast (time constant 1/4 s), the time variation analysis of the sound pressure level (noise level) applied with the A characteristic and the frequency analysis in the 1/12 octave band, and from the time of impact The average for 10 seconds was determined.

Experimental Result of Experiment 1 FIG. 17 is a graph showing the frequency analysis result of the measured sound in Experiment 1. It can be seen from FIG. 17 that many peaks are seen. This is due to the resonance of the chisel itself. Table 1 below shows typical peak frequencies and noise levels (peak noise levels) in FIG. Each peak showed very steep characteristics, and it was found that the overall noise level was determined by these peaks. It was also found that the overall noise level of the sound emitted from the conventional chisel (noise level in all frequency bands) showed a high value of 69.54 dB (A) when the power average of 10 hitting experiments was taken. .

  FIG. 18 is a graph showing temporal changes in the noise level of the measured sound in Experiment 1. FIG. 19 is a graph showing the relationship between the frequency of the measured sound in Experiment 1, the time (time) when the frequency was detected, and the noise level. It can be seen from FIG. 18 that the noise level becomes maximum immediately after the impact and then gradually attenuates. The power average of the maximum value of 10 impact experiments showed a high value of 82.41 dB (A). In addition, as shown in FIG. 19, immediately after hitting, a sound having a peak in the vicinity of 5.5 kHz (peak 4 sound) is dominant, and thereafter, a sound having another low-order mode peak is dominant. I understand that When heard with the human ear, the sound immediately after striking (the sound with the highest noise level) is most disturbing, but the reverberant sound after that is still harsh. On the other hand, the sounds other than the peaks 1 to 5 (the sound having the frequency at which the peak did not appear in FIG. 18) are quickly attenuated immediately after the impact, and the sound generated when the chisel is struck has a large weight. I found out that it was not occupied.

  If the sound of peak 1 to 5 (especially, the sound of peak 1 to 4 in the frequency band of 1 to 5 kHz that can be easily heard by human ears) can be suppressed from the results of the experiment 1, the annoying noise generated from the chisel Can be effectively reduced. As described above, the sounds of peaks 1 to 5 are due to resonance of the chisel itself. Therefore, if the resonance of the chisel itself can be suppressed, it is considered that the annoying noise generated from the chisel can be greatly reduced.

[Experiment 2]
-Experimental method of Experiment 2 Subsequently, Experiment 2 was conducted in order to further elucidate the generation mechanism of the noise generated from the chisel when hitting a hitting object with a conventional chisel. Specifically, as shown in FIG. 20, the acceleration generated at each point of the chisel when the base end surface of the chisel suspended in an anechoic chamber is struck with an impulse hammer is measured by an acceleration sensor (three-axis acceleration). The vibration mode of the chisel was analyzed by measuring with a pickup. FIG. 20 is a diagram showing an outline of Experiment 2. Six acceleration sensors are used, and each of these acceleration sensors is divided into two parts: a base segment of the chisel, a line segment connecting the base end and the tip of the chisel, and a pair of the line segments. The line segment was attached in a line at a position where the line segment was internally divided by 3, a position where the line segment was internally divided by 3 to 2, a position where the line segment was internally divided by 4 to 1, and the tip of the chisel.

Experimental Results of Experiment 2 FIG. 21 is a graph showing the analysis results of the vibration mode in Experiment 2. The frequency is slightly shifted from the peaks 1, 2, 3, and 4 (peaks 1, 2, 3, and 4 in Table 1 above) that appear in Experiment 1 because of the influence of the weight of the acceleration sensor. Vibration modes 1, 2, 3, and 4 shown in FIG. 21 correspond to peaks 1, 2, 3, and 4 in Table 1, respectively. Referring to FIG. 21, the vibration modes 1, 2, 3 (peaks 1, 2, 3) are transverse vibration (bending vibration) modes in a direction perpendicular to the center line of the chisel, and mode 4 (peak 4). Is a longitudinal vibration (stretching vibration) mode in a direction parallel to the center line of the chisel.

[Simulation 1]
-Method of simulation 1 Subsequently, a simulation 1 was performed in which a vibration mode generated in the chisel when hitting a hitting object with a conventional chisel is calculated by a finite element method (FEM). In simulation 1, a cylinder (round bar) having the same overall length and diameter as the conventional chisel used in Experiment 2 was defined as a chisel model. The chisel of the simulation 1 is different from the chisel used in the experiment 2 above, but the tip portion is not tapered, and the mounting recess is not formed in the outer peripheral portion near the base end. The vibration form is considered to be substantially the same as that of the chisel in Experiment 2.

Results of simulation 1 FIG. 22 is a diagram showing mode analysis results by the finite element method in simulation 1. FIG. 22 shows that the same vibration mode as in Experiment 2 appears in the mode analysis by the finite element method. In addition, the vibration mode 4 that appears as the longitudinal vibration mode in the experiment 2 is the first longitudinal vibration mode in the simulation 1 (the center of the chisel does not move, and the vicinity of the tip end and the base end of the chisel are in the opposite directions ( It can also be seen that this is a vibration mode that vibrates in the opposite phase).

[Summary of Experiments 1 and 2 and Simulation 1]
The results obtained from the experiments 1 and 2 and the simulation 1 are summarized as follows.
(1) The sound generated from the chisel when hitting the hitting object with the chisel is mainly due to the resonance of the chisel's vibration mode. Therefore, if the chisel's resonance is suppressed, the noise generated from the chisel is effective. Can be suppressed.
(2) The most annoying sound immediately after hitting the hitting object with the chisel is mainly due to the sound of peak 4, that is, the resonance of the primary longitudinal vibration mode (vibration mode 4) of the chisel. It can be effectively reduced by suppressing the resonance of the primary longitudinal vibration mode of the chisel.
(3) The reverberation sound generated from the chisel when hitting the hitting object with the chisel is mainly the sound of the peaks 1, 2, 3, that is, the bending vibration mode of the chisel (vibration modes 1, 2, 3). Since it is due to resonance, it can be effectively reduced by suppressing the resonance of the chisel bending vibration mode.

[Experiment 3]
-Experimental method of Experiment 3 To confirm the effectiveness of the chisel according to the present invention, a microphone is used to measure the sound emitted when a rigid sphere hits the base end surface of the chisel suspended in an anechoic chamber vertically. Then, Experiment 3 was performed to analyze the measured sound. Experiment 3 uses the chisel of the first embodiment shown in FIGS. 1 to 3 (Example 1) and the chisel obtained by removing the shock absorber 30 from the chisel of the first embodiment shown in FIGS. Example 2 and the case of using a chisel obtained by removing the chisel vibrating body 20 and the shock absorber 30 from the chisel of the first embodiment shown in FIGS. 1 to 3 (Comparative Example 1) It was. However, the chisel used in Examples 1 to 3 is not formed in a tapered shape at the tip end side of the chisel body 10 and is in a columnar shape. The specific method of Experiment 3 is the same as that of Experiment 1.

-Experimental result of experiment 3 The experimental result of experiment 3 is shown to FIGS. FIG. 23 is a graph showing the frequency analysis result of the sound emitted from the chisel of Example 1 in Experiment 3. FIG. 24 is a graph showing the frequency analysis result of the sound emitted from the chisel of Example 2 in Experiment 3. FIG. 25 is a graph showing the frequency analysis result of the sound emitted from the chisel of Comparative Example 1 in Experiment 3.

  Referring to FIG. 25, in the chisel of Comparative Example 1 that does not have the chisel vibrator and the buffer body, as in Experiment 1 (FIG. 17), many sharp peaks appear in the noise level. It can be seen that the effect of resonance of a number of vibration modes of the chisel body appears. In addition, the overall noise level of the sound emitted from the chisel of Comparative Example 1 (noise level in all frequency bands) is 64.18 dB (A) when taking the power average of 10 impact experiments, which is the noise level of the initial sound. The 10 times power average of the maximum value was 77.82 dB (A), both showing high values. That is, from the chisel of the comparative example 1, the overall noise level was about 69.54 dB (A), and the 10 times power average of the maximum noise level of the initial sound was 82.41 dB (A). It can be seen that a similar high level of noise is emitted, although it is about 5 dB (A) lower than the chisel used in Experiment 1.

  On the other hand, in the chisel of the first embodiment having the chisel vibrator and the buffer body, as shown in FIG. 23, almost no sharp peak appears in the noise level. It can be seen that the resonance in the transverse vibration mode is suppressed almost completely. In addition, the 10-time power average of the overall noise level (noise level in all frequency bands) of the sound emitted from the chisel of Example 1 is 55.63 dB (A), the 10-time power average of the maximum value of the noise level of the initial sound. Compared with the case of using the chisel of Comparative Example 1, the overall noise level is 8.6 dB (A), and the initial noise level is 7.79 dB (A). ) Compared to the case of using the conventional chisel (the chisel used in Experiment 1), the overall noise level is 13.91 dB (A), and the maximum initial sound level is 12.38 dB (A). I also found that it was reduced. That is, it was found that when the chisel of Example 1 having a chisel vibrator and a buffer is used, noise can be greatly reduced as compared with a chisel without a chisel vibrator and a buffer.

  On the other hand, in the chisel of Example 2 that has a chisel vibrator but does not have a buffer, a peak appears in the noise level in the vicinity of 4 kHz, which is the resonance frequency of the longitudinal vibration mode, as shown in FIG. However, it can be seen that there are almost no steep peaks appearing in other frequency bands including the resonance frequency of the transverse vibration mode. That is, when the chisel of Example 2 is used, the resonance in the transverse vibration mode can be significantly suppressed, and a remarkable effect is recognized in reducing the reverberation sound, but the effect of suppressing the resonance in the longitudinal vibration mode is not so much recognized. As a result, it was found that there was not much effect on the reduction of the initial sound. The reason why the longitudinal vibration mode resonance could not be suppressed so much in the chisel of the second embodiment is that a secondary impact force in the vertical direction is applied to the chisel body when the chisel vibrator that performs longitudinal vibration collides with the chisel body. This is thought to be due to the occurrence of new vertical vibrations in the chisel body due to the secondary impact force.

  As described above, from the experimental results of Experiment 2, the chisel provided with the chisel vibrating body has a certain noise prevention effect even when it does not have a buffer, but in order to further enhance the noise prevention effect, It was found that it is important to suppress the secondary impact force applied from the chisel vibrator to the chisel body by providing a buffer.

DESCRIPTION OF SYMBOLS 10 Chisel body 10a Insertion groove 10b Insertion groove 10c Through-hole 10d Cavity part 11 First member 12 Second member 13 Connection member 20 Chisel vibrator 30 Buffer body D ₁ The outer diameter of the chisel body (the insertion groove is provided. No outside diameter)
Outer diameter of D ₁ chisel body (outside diameter of a portion Hamakomimizo is provided)
d ₁ Inner diameter of chisel vibrator L Center line of chisel body L ₁ Total length of chisel body L ₂ Total length of chisel vibrator L ₃ Distance from tip of chisel body to vibration center of chisel vibrator L _{X From} tip of chisel body to target Distance to point W Width of ₁ insertion groove

Claims (5)

A chisel body that crushes the hitting object by applying a striking force at its tip;
A chisel vibrator incorporated in the chisel body in a state capable of longitudinal vibration relative to the chisel body,
Consists of
The ratio M ₂ / M ₁ of the mass M ₂ of the chisel vibrator to the mass M ₁ of the chisel body is 0.01 to 0.5,
The ratio L ₂ / L ₁ of the overall length L ₂ of the chisel vibrator to the overall length L ₁ of the chisel body is 0.05 to 0.3,
The ratio L ₃ / L ₁ of the distance L ₃ from the tip of the chisel body to the center of the chisel vibrating body with respect to the total length L ₁ of the chisel body is 0.6 or more and less than 1-L ₂ / 2L ₁
The ratio of the width W _{1 in} the direction parallel to the center line of the chisel body of the fitting groove to the total length L ₂ of the chisel vibrating body with the chisel vibrating body fitted in the fitting groove provided on the outer peripheral surface of the chisel body. W ₁ / _{L 2,} along with are 1.01 to 2,
In the gap between the distal end surface of the chisel vibrator and the inner wall surface on the distal end side of the fitting groove, and the gap between the proximal end surface of the chisel vibrator and the inner wall surface on the proximal end side of the fitting groove, elastic material, viscosity A buffer made of a material or viscoelastic material is arranged,
A chisel characterized in that a chisel vibrating body vibrates longitudinally in response to vibration generated in a chisel body when hitting a hitting object, thereby reducing noise generated therefrom.
The chisel according to claim 1, wherein a buffer body made of an elastic material, a viscous material, or a viscoelastic material is also disposed in a gap between the outer peripheral surface of the chisel body and the inner peripheral surface of the chisel vibrating body.
A chisel body that crushes the hitting object by applying a striking force at its tip;
A chisel vibrator incorporated in the chisel body in a state capable of longitudinal vibration relative to the chisel body,
Consists of
The ratio M ₂ / M ₁ of the mass M ₂ of the chisel vibrator to the mass M ₁ of the chisel body is 0.01 to 0.3,
The ratio L ₂ / L ₁ of the overall length L ₂ of the chisel vibrator to the overall length L ₁ of the chisel body is 0.05 to 0.3,
The ratio L ₃ / L ₁ of the distance L ₃ from the tip of the chisel body to the center of the chisel vibrating body with respect to the total length L ₁ of the chisel body is 0.6 or more and less than 1-L ₂ / 2L ₁
A chisel vibrating body is inserted into a through hole provided through the chisel body in a direction perpendicular to the center line thereof, and is parallel to the center line of the chisel body of the through hole with respect to the entire length L ₂ of the chisel vibrating body. The ratio W ₁ ′ / L ₂ of the width W ₁ ′ in any direction is set to 1.01-2,
An elastic material, a viscous material, or a gap between the tip surface of the chisel vibrator and the inner wall surface on the tip side of the through-hole, and a gap between the base end surface of the chisel vibrator and the inner wall surface on the base end side of the through-hole A buffer made of viscoelastic material is arranged,
A chisel characterized in that a chisel vibrating body vibrates longitudinally in response to vibration generated in a chisel body when hitting a hitting object, thereby reducing noise generated therefrom.
A chisel body that crushes the hitting object by applying a striking force at its tip;
A chisel vibrator incorporated in the chisel body in a state capable of longitudinal vibration relative to the chisel body,
Consists of
The ratio M ₂ / M ₁ of the mass M ₂ of the chisel vibrator to the mass M ₁ of the chisel body is 0.01 to 0.5,
The ratio L ₂ / L ₁ of the overall length L ₂ of the chisel vibrator to the overall length L ₁ of the chisel body is 0.05 to 0.3,
The ratio L ₃ / L ₁ of the distance L ₃ from the tip of the chisel body to the center of the chisel vibrating body with respect to the total length L ₁ of the chisel body is 0.6 or more and less than 1-L ₂ / 2L ₁
A chisel vibrating body is housed in a hollow portion provided inside the chisel body, and a ratio W ₁ of a width W ₁ ″ of the hollow portion in the direction parallel to the center line of the chisel body with respect to the entire length L ₂ of the chisel vibrating body. "/ L ₂ is set to 1.01-2,
An elastic material, a viscous material, or a gap between the tip surface of the chisel vibrator and the inner wall surface on the tip side of the cavity and the gap between the base surface of the chisel vibrator and the inner wall surface on the base side of the cavity A buffer made of viscoelastic material is arranged,
A chisel characterized in that a chisel vibrating body vibrates longitudinally in response to vibration generated in a chisel body when hitting a hitting object, thereby reducing noise generated therefrom.
The chisel according to any one of claims 1 to 4, wherein the chisel vibrating body is provided at a plurality of locations spaced in the direction of the center line of the chisel body.