JP2002283254A - Shock tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shock tool capable of inexpensively and further effectively restraining vibration and noise. SOLUTION: This shock tool has a synthetic resin motor casing 8, and a non-resin gear casing 6. A deformable shock absorbing member 7 is arranged on a laminated surface of the resin motor casing 8 and the non-resin gear casing 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impact tool having a motor casing made of synthetic resin and a gear casing made of non-resin.

[0002]

2. Description of the Related Art Impact tools in which a casing is made of resin have already been proposed and are known. In particular, a synthetic resin casing is frequently used for a motor casing incorporating a motor for the purpose of weight reduction, double insulation, and the like. An example of such an impact tool will be described with reference to FIG.

[0003] The rotation of the drive motor 28 is transmitted to an impact drive unit via a gear 27, and a striking force is transmitted to a tip tool (not shown). Specifically, the rotation of the drive motor 28 is transmitted to a crankshaft 26 that can rotate integrally with the gear 27 through a pinion 29 provided at the tip of the drive motor 28 and a gear 27 that meshes with the pinion 29. The piston 24 is reciprocated in the cylinder 23 via the connecting rod 25. Due to the reciprocating motion of the piston 24, the air pressure in the air chamber 30 formed between the piston 24 in the cylinder 23 and the impact element 22 fluctuates, so that the impact element 22 reciprocates. And the meson 21 transmits a striking force to a tip tool (not shown).

[0004] Reference numeral 2 in the drawing denotes a tip tool retaining member for preventing a tip tool (not shown) from falling off, and 3 denotes a cylinder case for accommodating a cylinder or the like.
Is fixed to the cylinder case 3 by a fastening member (not shown).

[0005] Reference numeral 5 denotes a crankcase for accommodating a crank portion and the like, 6 denotes a non-resin gear casing made of aluminum, magnesium or steel material for supporting one of the drive motors, and 8 denotes a drive motor or the like. The motor casing is made of a synthetic resin, and the crankcase 5, the gear casing 6, and the motor casing 8 are fixed by a fastening member (not shown).

The gear casing 6 includes a motor casing 8
A bearing 6a that supports the pinion 29 of the motor 28 housed therein and that supports the motor 28 side end of the shaft 26a of the crankshaft 26 extending parallel to the pinion 29 of the motor 28 is provided. The shaft portion 26a of the crankshaft 26 is supported by a bearing 5a held by the crankcase 5 at an upper portion in the drawing.

As described above, the impact tool shown in FIG.
3, the striking element 22 is reciprocated by changing the air pressure in the air chamber 30 so that the striking element 22 collides with the meson 21 and the striking force is transmitted to a tip tool (not shown). During the impact operation, a reaction force is applied to the piston 24 when the air pressure in the air chamber 30 is compressed or when the striker 22 strikes the tip tool, and this reaction force is transmitted through the connecting rod 25. Joins the crankshaft 26. The reaction force applied to the crankshaft 26 is generated in the right direction in the drawing, that is, in the direction away from the piston 24, and the crankshaft 26 tries to move in the direction away from the piston 24 by this reaction force. The position is maintained by the bearing portions of the crankcase 5 and the gear casing 6. As described above, since the reaction force applied to the crankshaft 26 is transmitted to the crankcase 5 and the gear casing 6 via the crankshaft 26, the crankshaft 5 and the gear casing 6 are made of aluminum having a hardness not deformed by the reaction force. It is formed of a non-resin material such as magnesium or steel.

The handle 10 is elastically attached to the non-resin crankcase 5 and the resin motor casing 8, and the handle 10 is provided with a switch 9 and a power cord 11.

[0009]

In the conventional impact tool described above, the impact force generated by the collision between the striker 22 and the meson 21 and the collision between the meson 21 and the tip tool (not shown) at the time of operation is transmitted to the cylinder 23 via the cylinder 23. The impact force is transmitted to the case 3 and to the crankcase 5 and the gear casing 6. Further, the reaction force applied to the piston 24, the connecting rod 25, and the crankshaft 26 generated when the piston 24 reciprocates due to the rotational drive of the crankshaft 26 and the pressure in the air chamber 30 becomes high pressure is applied to the crankshaft 26 as an impact force. The power is transmitted to the supporting crankcase 5 and gear casing 6.

The impact force transmitted to the non-resin crankcase 5 and the gear casing 6 along the above-described path is transmitted to a synthetic resin motor casing 8 coupled to the gear casing 6 via a fastening member (not shown). This impact force vibrates the resin casing 8 made of resin having low rigidity, and generates noise due to the generation of the vibration. In particular, the gear casing 6 made of non-resin and the motor casing 8 made of synthetic resin are usually fixed by about four or six fastening members. The resin-made motor casing 8 having a shape close to a ring generates out-of-plane vibrations such that the ring becomes elliptical with the fastening portion as a node, generating noise.

The impact force applied to the gear casing 6 includes an impact force transmitted through the crankcase 5, a bearing 6 b that supports the crankshaft 26, and the pinion 2.
9 at the time of operation via a bearing 6a which supports the motor casing 9, and these impact forces are transmitted from the gear casing 6 to the motor casing 8 8 will be transmitted.

SUMMARY OF THE INVENTION An object of the present invention is to provide an impact tool which can solve the above-mentioned drawbacks and can suppress vibration and noise at low cost and more effectively.

[0013]

The above object is achieved by providing a deformable cushioning member on the mating surface between a motor casing made of synthetic resin and a gear casing made of non-resin.

[0014] The present invention is also achieved by providing resistance means for suppressing relative movement between a motor casing made of synthetic resin and a gear casing made of non-resin.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the impact tool of the present invention will be described below with reference to FIGS. The description of the parts having the same configuration as the conventional impact tool will be omitted.

As shown in FIG. 1, a cushioning member is provided on the mating surface between the gear casing 6 which supports the pinion 29 of the drive motor (not shown) and one end of the crankshaft 26 and the motor casing 8 made of synthetic resin. A motor casing 8 made of resin, a cushioning member 7, a gear casing 6 made of non-resin, and a crankcase 5 that supports a part of the crankshaft 26 are fixed by a fastening member 12. Reference numeral 1 in the drawing is a tip tool for performing drilling, filing work and the like.

As shown in the overall perspective view of FIG. 1 and the development of the main part of FIG. 2, the crankcase 5, the gear casing 6, the cushioning member 7, and the motor casing 8 are connected to a fastening member 12 (4
The cushioning member 7 is located between the mating surfaces of the gear casing 6 and the motor casing 8 in a state of being compressed and deformed by the mating surfaces of the gear casing 6 and the motor casing 8.

By arranging the deformable cushioning member 7 between the mating surfaces of the gear casing 6 and the motor casing 8 as described above, the shock force transmitted to the gear casing 6 due to the deformation of the cushioning member 7 is transmitted to the motor. Transmission to the casing 8, that is, vibration of the motor casing 8 can be suppressed.

Further, since the cushioning member 7 is located between the mating surfaces of the gear casing 6 and the motor casing 8 in a state of being compressed and deformed, it is possible to increase the restraining force at a portion other than the fastening portion where the fastening member 12 is located. A low-rigidity motor casing 8 having a cylindrical shape having a shape close to an annular shape can suppress occurrence of out-of-plane vibration such that an annular shape becomes an ellipse with a fastening portion as a node, thereby suppressing generation of noise. Become. That is, the buffer member 7 functions to attenuate the vibration of the motor casing 8.

The material of the cushioning member 7 may be paper having a certain thickness dimension, a material mainly composed of rubber or metal fiber, or a composite material of the material, or a motor casing 8 made of synthetic resin. A material mainly composed of a resin such as vinyl having higher viscoelasticity and a composite material with the material may be used. The thickness of the cushioning member 7 is not particularly limited, and the effect is improved if the thickness is increased. However, it is needless to say that it is necessary to secure rigidity such that gears and other components operate normally.

In this embodiment, the thickness is 0.5 m
m, when using the cushioning member 7 mainly composed of rubber,
During operation, the vibration of the resin motor casing 8 was reduced by half, and the noise level was reduced by 2 dB.

Further, when the cushioning member 7 is made of a material having a more viscoelasticity than the motor casing 8, the generation of out-of-plane vibration in the motor casing 8 can be further suppressed, and the generation of noise can be suppressed. be able to.

In the above embodiment, the cushioning member 7 has both the effect of suppressing the transmission of vibration from the gear casing 6 to the motor casing 8 and the effect of suppressing out-of-plane vibration generated in the motor casing 8. However, by providing a resistor for suppressing relative movement between the gear casing 6 and the motor casing 8, only one effect of suppressing out-of-plane vibration of the motor casing 8 can be obtained. It is good also as having.

Next, another embodiment of the impact tool of the present invention will be described with reference to FIGS. FIG. 4 is a longitudinal sectional view showing another embodiment of the impact tool of the present invention, and FIG. 5 is a developed view of a main part of FIG.

In this embodiment, the housing 41 has a structure in which the drive motor 28 and the crankshaft 26 are housed. The housing 41 includes a non-resin gear casing 6 that supports the pinion 29, the first gear 42 and the crankshaft 26, the piston 24, and the connecting rod 2.
5, a meson 21 and a cylinder case 3 for accommodating a striker 22 having a cylindrical shape and forming an air chamber 30 with the piston 24 are directly attached. A motor casing 40 made of a synthetic resin is provided in a portion for housing the drive motor 28 for the purpose of double insulation.

In this embodiment, as shown in FIG. 5, a buffer member 7 is provided between the housing 41 and the mating surface of the non-resin gear casing 6. This buffer member 7
Is disposed between the mating surfaces of the motor casing 40 and the gear casing 6 and suppresses transmission of the impact force applied to the gear casing 6 to the motor casing 40, as in the embodiment shown in FIGS. It has the effect of doing.

[0027] The impact tool of the present invention can be used for the impact tool 2 during the impact operation.
The impact force generated due to the collision between the meson 2 and the meson 21 and between the meson 21 and the tool bit 1 is transmitted to the housing 41 through the cylinder case 3. , Connecting rod 2
5. The transmission of the impact force transmitted to the non-resin gear casing 6 through the crankshaft 26 to the motor casing 40 can be suppressed by the presence of the buffer member 7. The cover 44 has a function of supporting the crankshaft 26 and the first gear 42.

The above-mentioned cushioning member is used for the motor casing 40.
It is desirable that the motor casing 40 be disposed in a compressed state between the mating surfaces of the gear casing 6 and the gear casing 6 so that the motor casing 40 can be prevented from vibrating out of plane due to the impact force transmitted at the time of hitting. Become. In addition,
The noise reduction effect in the present embodiment was 1.5 dB.

In the figure, reference numeral 43 denotes a final gear for transmitting the rotation of the first gear 42 to the crankshaft 26;
5 is a tip tool holding member.

Normally, lubricating material is injected into the vicinity of the piston 24 and the crankshaft 26 for the purpose of extending the life. The above-mentioned cushioning member 7 is located between the mating surfaces of the housing 41 and the gear casing 6. In addition, in order to prevent the lubricant from leaking from between the mating surfaces of the housing 41 and the gear casing 6, a seal portion is provided.

Although the cushioning member 7 shown in FIGS. 2 and 5 has a simplified shape in consideration of productivity, it must be disposed at the contact portion between the gear casing and the motor casing, and the gear casing and the motor casing must be in direct contact. Only, without any other restrictions.

[0032]

As described above, according to the present invention, the cushioning member is provided between the motor casing made of synthetic resin and the gear casing made of non-resin, so that the impact driving parts can be crushed, Transmission of an impact force to the motor casing due to an applied reaction force or the like can be suppressed, and an impact tool with low vibration and low noise can be provided.

[Brief description of the drawings]

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

FIG. 2 is a development view of a main part of FIG. 1;

FIG. 3 is a longitudinal sectional view showing an example of an impact tool.

FIG. 4 is a vertical sectional view of a main part showing another embodiment of the impact tool of the present invention.

FIG. 5 is a development view of a main part of FIG. 4;

[Explanation of symbols]

1 is a tip tool, 2 is a tip tool retaining member, 3 is a cylinder case, 4 is a side handle, 5 is a crankcase,
6 is a non-resin gear casing, 7 is a buffer member, 8 is a synthetic resin motor casing, 9 is a switch, 10 is a handle, 11 is a power cord, and 12 is a fastening member.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mutsui Harada 1060 Takeda, Hitachinaka-shi, Ibaraki F-term in Hitachi Koki Co., Ltd. (Reference) 2D058 AA11 CB06 CB12 DA15 DA33 DA34

Claims (2)

[Claims] 1. A motor, a gear engaged with a pinion of the motor, a crankshaft to which the rotation of the motor is transmitted via the gear and driven to rotate, and a tip tool holding portion for detachably holding a tip tool A striking mechanism that reciprocates in the axial direction of the tip tool by rotating the crankshaft to strike the tip tool, a synthetic resin motor casing that houses the motor, the crankshaft and the pinion. An impact tool having a non-resin gear casing rotatably supported, and wherein the motor casing and the gear casing are fixed by a fastening member, the impact tool being deformable between the motor casing and the gear casing. An impact tool comprising a buffer member. 2. The impact tool according to claim 1, wherein the buffer member is formed of a material having a higher viscoelasticity than the motor casing.