JP2008062338A - Power tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power tool which improves the operability and working efficiency and prevents damage and breakage of a body by increasing the heat insulation and shock absorbing capability of an elastic cover. <P>SOLUTION: The impact driver 1 (the power tool) 1 includes: a driving source; a speed reducing mechanism part for decelerating the rotation of the driving source; an impact mechanism part for converting the rotation of the driving source reduced in speed by the speed reducing mechanism part to the rotary impact force, and transmitting the same to a tip tool; a hammer case 3 for storing the impact mechanism part; and the cylindrical elastic cover 15 covering the outer peripheral surface of the hammer case 3. A plurality of ribs 15a extending all over the full length in the axial direction are formed on the inner peripheral surface of the hammer case 3 of the elastic cover 15 extending over the whole periphery in the peripheral direction, and the inner peripheral surface outside of the ribs 15a of the elastic cover 15 is in non-contact with the outer peripheral surface of the hammer case 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a portable power tool such as an impact driver that converts rotation of a drive source such as a motor into a rotational impact force and transmits the rotation impact force to a tip tool.

  A power tool such as an impact driver has a motor as a drive source, a speed reduction mechanism that decelerates the rotation of the motor, and converts the rotation of the motor decelerated by the speed reduction mechanism into a rotational impact force and transmits it to the tip tool. It is comprised by the case etc. which accommodate the impact mechanism part to perform and this impact mechanism part.

By the way, in this type of power tool, a configuration is adopted in which the outer peripheral surface of the case is covered with a cylindrical elastic cover in order to prevent the workpiece and the power tool body from being damaged and to prevent the gripping portion of the power tool body from slipping. (For example, refer to Patent Document 1). In this case, the elastic cover is formed of an elastic body having substantially the same thickness, and covers the outer peripheral surface of the case with its inner peripheral surface being in close contact with the entire outer peripheral surface of the case.
Japanese Patent Laying-Open No. 2005-028572

  However, if the case is covered with the elastic cover in close contact with the entire outer peripheral surface of the case as in the prior art, heat generated in the striking mechanism and the like in the case is transferred from the case to the elastic cover, and the elastic cover becomes hot. Therefore, there is a problem in that an operator who holds this part feels uncomfortable and the operability and workability are impaired.

  In addition, an elastic cover composed of an elastic body having substantially the same thickness is not easily deformed because its rigidity is relatively large, and since the impact absorbing ability is low, the elastic cover is easily damaged when hit against wood, metal, etc. Further, when the operator accidentally drops the power tool, there is a problem that the power tool body is damaged by the impact.

  The present invention has been made in view of the above problems, and its objective is to improve the heat insulation and shock absorption capacity of the elastic cover to improve operability and workability, prevent damage to the main body and prevent damage, etc. It is to provide a power tool that can.

  In order to achieve the above object, the invention described in claim 1 is directed to a drive source, a speed reduction mechanism that decelerates the rotation of the drive source, and the rotation of the drive source that is decelerated by the speed reduction mechanism is converted into a rotational impact force. An outer peripheral surface of the case of the elastic cover in a power tool including a striking mechanism portion that transmits to the tip tool, a case that houses the striking mechanism portion, and a cylindrical elastic cover that covers the outer peripheral surface of the case A plurality of ribs extending over the entire length in the axial direction are formed on the inner peripheral surface in contact with the entire length in the circumferential direction, and the inner peripheral surface of the portion of the elastic cover excluding the ribs is formed with respect to the outer peripheral surface of the case It is characterized by non-contact.

  According to a second aspect of the present invention, in the first aspect of the invention, the ring-shaped stopper that prevents the elastic cover from falling off from the case is formed of an elastic member, and the stopper is locked to the outer periphery of the case. It is characterized in that a ring-shaped locking projection is formed.

  According to the first aspect of the present invention, the plurality of ribs formed on the inner peripheral surface of the elastic cover over substantially the entire circumference between the inner peripheral surface of the portion excluding the rib of the elastic cover and the outer peripheral surface of the case. Since a plurality of air layers are formed, heat transfer from the case to the elastic cover is blocked by the heat insulating action of these air layers, and the temperature rise of the elastic cover is prevented. For this reason, an operator who holds the elastic cover during work does not feel uncomfortable, and the worker can easily hold the elastic cover and perform the work stably with good operability and workability.

  In addition, an elastic cover having ribs on the inner peripheral surface is less rigid and more easily deformed than conventional elastic covers made of an elastic body having substantially the same thickness. Therefore, even if the elastic cover hits wood or metal, it is difficult to be damaged, and even if the operator accidentally drops the power tool, the impact is effectively absorbed and the power tool main body is prevented from being damaged.

  According to the second aspect of the present invention, the stopper made of an elastic member can be easily deformed, and the stopper can be easily engaged / disengaged with one touch with respect to the ring-shaped locking projection formed on the outer periphery of the case. Therefore, the elastic cover can be easily attached to and detached from the case.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 is a left side view of an impact driver as an embodiment of a power tool according to the present invention, FIG. 2 is a right sectional view showing an internal structure of the impact driver, and FIGS. 3 and 4 are exploded perspective views of the main part of the impact driver. FIG.

  First, the basic configuration and operation of the impact driver 1 according to the present invention will be described with reference to FIGS. 1 and 2. The illustrated impact driver 1 has a housing 2 and a hammer case 3 which are outer frames forming an outer shape. The housing 2 includes a substantially cylindrical body portion 2A extending in the front-rear direction, and a handle portion 2B connected to the body portion 2A so as to form a substantially T shape in a side view. In the body 2A of the housing 2, a motor 4 as a drive source and a planetary gear mechanism 5 as a speed reduction mechanism for decelerating the rotation of the motor 4 are accommodated as shown in FIG. The hammer case 3 accommodates an impact mechanism that converts the rotation of the motor 4 decelerated by the planetary gear mechanism 5 into a rotational impact force and transmits it to a tip tool (not shown). Details of the striking mechanism will be described later.

  Further, as shown in FIG. 2, a switch 7 having a trigger 6 at the upper portion and a battery receiving portion 8 at the lower portion are accommodated inside the handle portion 2B of the housing 2, and the lower end of the handle portion 2B is charged. A battery 9 as a possible power source is detachably mounted.

  Thus, in such an impact driver 1, when the operator activates the trigger 6 to start the motor 4, the rotation of the output shaft (motor shaft) 4a of the motor 4 is decelerated by the planetary gear mechanism 5. It is transmitted to the spindle 10 and the spindle 10 is rotationally driven at a predetermined speed. Here, the spindle 10 and the hammer 11 are connected by a cam mechanism, and this cam mechanism is formed on the V-shaped spindle cam groove 10 a formed on the outer peripheral surface of the spindle 10 and the inner peripheral surface of the hammer 11. Further, it is composed of a V-shaped hammer cam groove 11a and balls 12 that engage with these cam grooves 10a, 11a.

  Further, the hammer 11 is always urged by the spring 13 in the tip direction (rightward in FIG. 2), and at the time of rest, the clearance between the end surface of the anvil 14 and the gap is established by the engagement between the ball 12 and the cam grooves 10a and 11a. In the position. And the convex part is each symmetrically formed in two places on the rotation plane which the hammer 11 and the anvil 14 oppose. A tip tool (not shown) is detachably attached to the anvil 14.

  By the way, when the spindle 10 is rotationally driven at a predetermined speed as described above, the rotation of the spindle 10 is transmitted to the hammer 11 through the cam mechanism, and the hammer 11 is not rotated halfway. 11 is engaged with the convex portion of the anvil 14 and the anvil 14 is rotated. When the relative reaction between the hammer 11 and the spring 13 occurs due to the reaction force of the engagement, the hammer 11 Then, the spring 13 starts to retract toward the motor 4 side while compressing the spring 13 along the spindle cam groove 10a of the cam mechanism.

  When the protrusion of the hammer 11 moves over the protrusion of the anvil 14 due to the backward movement of the hammer 11 and the engagement between the two is released, the hammer 11 accumulates in the spring 13 in addition to the rotational force of the spindle 10. While being accelerated rapidly in the rotational direction and forward by the action of the elastic energy and the cam mechanism, the spring 13 is moved forward by the biasing force of the spring 13, and the convex portion is reengaged with the convex portion of the anvil 14 to be integrated. Begin to rotate. At this time, since a strong rotational impact force is applied to the anvil 14, the rotational impact force is transmitted to a screw (not shown) via a tip tool attached to the anvil 14.

  Thereafter, the same operation is repeated, and the rotational impact force is intermittently and repeatedly transmitted from the tip tool to the screw, and the screw is screwed into a material to be fastened such as wood.

  Next, a configuration in front of the body portion 2A of the housing 2 will be described.

  The cylindrical hammer case 3 which is a part of the body portion 2A of the housing 2 and is provided in front of the housing 2 is made of an aluminum alloy, and the outer periphery thereof is an elastic cover made of a soft material such as an elastomer ( Protector) 15. The elastic cover 15 is fixed to the hammer case 3 by a ring-shaped stopper (front cap) 16 which is a fixing means made of an elastic body such as rubber, and the stopper 16 extends to the entire inner periphery thereof. The hammer case 3 is formed by fitting the formed locking groove 16a (see FIGS. 2 and 3) into a ring-shaped locking projection 3a (see FIGS. 2 and 4) integrally formed on the outer periphery of the hammer case 3. It is easily locked with one touch.

  Further, the stopper 16 can be easily removed from the hammer case 3 with one touch by deforming the stopper 16 and releasing the engagement with the locking protrusion 3a of the locking groove 16a. It can be easily removed.

  Here, the hammer case 3 and the elastic cover 15 are formed in a tapered shape in which the outer diameter gradually decreases from the rear toward the front, and the anvil 14 which is a tip tool holding portion protrudes from the tip of the hammer case 3. A tip tool (not shown) is detachably attached to the anvil 14. The reason why the hammer case 3 and the elastic cover 15 are tapered is that they do not get in the way in narrow work and that the tip of the tip tool is easy to see when viewed from behind.

  By the way, as shown in FIG. 3, the impact driver 1 according to the present invention has a plurality of ribs 15a extending substantially over the entire length in the axial direction on the inner peripheral surface in contact with the outer peripheral surface of the hammer case 3 of the elastic cover 15. It is formed over the entire circumference.

  Therefore, in the impact driver 1 according to the present invention, as shown in FIG. 1, an inner portion of the elastic cover 15 where the ribs 15 a are not provided by the plurality of ribs 15 a formed on the inner peripheral surface of the elastic cover 15. Since a plurality of air layers S (only one is shown in FIG. 2) are formed between the peripheral surface and the outer peripheral surface of the hammer case 3, the elastic cover 15 is formed from the hammer case 3 by the heat insulating action of these air layers S. The heat transfer to is blocked, and the temperature rise of the elastic cover 15 is prevented. For this reason, an operator who holds the elastic cover 15 during work does not feel uncomfortable, and the worker can easily hold the elastic cover 15 and perform the work stably with good operability and workability.

  Further, the elastic cover 15 having the ribs 15a formed on the inner peripheral surface is thin at the portion where the ribs 15a are not provided, and the inner peripheral surface is not in contact with the outer peripheral surface of the hammer case 3. , Because it is not in close contact with the outer peripheral surface of the hammer case 3, the rigidity is lower than that of a conventional elastic cover composed of an elastic body having substantially the same thickness, and the shock absorbing ability is enhanced. Even if the elastic cover 15 hits wood, metal or the like, it is difficult to be damaged, and even if the operator accidentally drops the impact driver 1, the impact is effectively absorbed and the impact driver 1 is prevented from being damaged.

  Furthermore, by easily deforming the stopper 16 made of an elastic member such as rubber, the stopper 16 can be easily engaged and disengaged with respect to the ring-shaped locking protrusion 3a formed on the outer periphery of the hammer case 3 with one touch. Therefore, the elastic cover 15 can be easily attached to and detached from the hammer case 3, and the elastic cover 15 can be easily replaced.

  Although the present invention has been described with respect to the embodiment in which the present invention is applied to a cordless impact driver including a rechargeable battery, the present invention can be similarly applied to a corded impact driver. In addition, the present invention is not limited to application only to impact drivers, but also to other various power electric tools such as hammer drills and other electric tools such as disc grinders, and pneumatic tools such as nailing machines. Of course, it can be widely applied.

It is a left view of the impact driver which concerns on this invention. It is right side sectional drawing which shows the internal structure of the impact driver which concerns on this invention. It is a disassembled perspective view of the impact driver principal part concerning the present invention. It is a disassembled perspective view of the impact driver principal part concerning the present invention.

Explanation of symbols

1 Impact driver (power tool)
2 Housing 2A Housing Body 2B Housing Handle 3 Hammer Case (Case)
3a Locking protrusion 4 Motor (drive source)
4a Motor output shaft (motor shaft)
5 Planetary gear mechanism (reduction mechanism)
6 trigger 7 switch 8 battery receiving portion 9 battery 10 spindle 10a spindle cam groove 11 hammer 11a hammer cam groove 12 ball 13 spring 14 anvil 15 elastic cover 15a rib 16 stopper 16a locking groove S air layer

Claims (2)

A driving source, a speed reducing mechanism that decelerates the rotation of the driving source, a striking mechanism that converts the rotation of the driving source decelerated by the speed reducing mechanism into a rotating striking force, and transmits it to the tip tool, and the striking mechanism In a power tool provided with a case that accommodates a portion and a cylindrical elastic cover that covers the outer peripheral surface of the case,
A plurality of ribs extending over the entire length in the axial direction are formed on the inner peripheral surface of the elastic cover that is in contact with the outer peripheral surface of the case, and the inner peripheral surface of the portion of the elastic cover excluding the ribs. A power tool characterized in that is made non-contact with the outer peripheral surface of the case.   A ring-shaped stopper that prevents the elastic cover from falling off from the case is formed of an elastic member, and a ring-shaped locking protrusion for locking the stopper is formed on the outer periphery of the case. The power tool according to claim 1.

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