JP4269335B2 - Hammer drill - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hammer drill equipped with a mechanism for preventing a continuous striking motion (hereinafter referred to as idle driving) of a striker when there is no load.
[0002]
[Prior art]
A piston provided with a motor for rotating in into a reciprocating cylinder is reciprocated, the end after the detachably retained tool bit in the tool holder causes interlocking striker through the air chamber in the cylinder a striking transmission mechanism for transmitting a blow to the tool bit by striking the parts and can abut mesons, a configuration and a rotation transmitting mechanism for transmitting the rotation of the motor to a tip tool through the cylinder and the tool holder and The hammer drill is held so as to be movable in the axial direction of the cylinder, and when the meson is constantly urged forward on the tip tool side and the meson moves in the rearward direction beyond the piston side, the breathing hole is closed. idle driving prevention mechanism of the prior art is employed in the hammer drill provided with a slide sleeve to open the ventilation hole when the the tip tool side forward in a state that has moved a predetermined or higher Examples include those disclosed in Japanese Patent Application No. 2002-268153 (JP 2003-211370).
[0003]
The idle driving prevention mechanism of the hammer drill is provided with an engaging section that engages with the sliding sleeve striker rear end portion outer periphery of the intermediate element, a dimension greater than the axial movement amount of the intermediate element to the cylinder and the tool holder outer periphery the long hole having provided, and the slide sleeve, and the annular member having a projection portion projecting cylinder outward of the long hole of the inner diameter portion and the cylinder to be engaged with the engagement portion of the intermediate element, the cylinder on the cylinder periphery is held movably in the axial direction, before end and a slide member which the rear end is urged to the tip tool side forward by the biasing means together to engage the projection of the circular member in the anti-tip tool side It has the structure, thereby for mesons are mesons near portion is struck by the striker will be retained by the circular member, radially intermediate element when the intermediate element is reciprocated Contact It was achieved so that it is possible to suppress the occurrence of Rubure.
[0004]
[Problems to be solved by the invention]
In the conventional hammer drill described above, since the movement of the annular member toward the striker side is not regulated, the annular member moves backward due to the impact during the striking operation , that is , the impact during the movement of the intermediate member toward the striker side. In other words , the ring member jumps up, and the ring member may collide with the end face of the striker or the piston of the cylinder and the tool holder long hole, resulting in damage.
[0005]
In addition, a shock absorbing member is arranged on the outer periphery of the striker side end of the intermediate element. However, if the shock absorbing member is simply provided, the shock absorbing member is repeatedly fatigued due to repeated stress, and the shock absorbing member reaches the end of its life quickly. As a result, there is a drawback that it does not serve as a buffer member.
[0006]
An object of the present invention is to eliminate the above-described drawbacks of the prior art and improve the durability of the hammer drill .
[0007]
[Means for Solving the Problems]
The above purpose is to provide a front step portion and a rear step portion located in front of the tip of the intermediate tool side and rear of the striker side, and abut against the front step portion and the rear step portion of the intermediate member during the backward movement of the intermediate member. the front cushioning member and the rear cushioning member provided to a buffer, it is possible to forward stepped portion is achieved by be Rukoto as rear stepped portion after the contact with the front cushioning member abuts against the rear cushioning member.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a hammer drill according to the present invention will be described with reference to FIGS. 1 and 2. In FIG. 1, it is assumed that the left side is the front, the right side is the rear, the leftward movement is forward, and the rightward movement is backward.
[0009]
First, the operation of the hammer drill in this embodiment will be described.
[0010]
Rotation of the motor 13 rotates the crankshaft 15 through the first gear 14, is converted by the connecting rod 16 to the reciprocating motion of the piston 17. A substantially sealed air chamber 18 is formed between the piston 17 and the striker 3 in the cylinder 4, and the pressure of the air chamber 18 fluctuates due to the reciprocating motion of the piston 17, and the striker 3 strikes the intermediate element 2. The striking motion is transmitted to the tip tool 1.
[0011]
On the other hand, rotation of the motor 13 and the second gear 20, through a first bevel gear 21 rotates the second bevel gear 22 which is rotatably provided on the cylinder 4. The second bevel gear 22 is provided with a plurality of engaging portions 22 a that protrude in the axial direction, and a key member 26 having an engaging portion 26 a that engages with the engaging portion 22 a is provided on the outer periphery of the cylinder 4. and the engaging portion 26b provided on the inner peripheral portion of the key member 26 is engaged with the engaging portion 4b provided in the cylinder 4 the outer circumference, rotation of the second bevel gear 22 is cylinder 4 And the cylinder 4 rotates.
[0012]
Further, rotation of the cylinder 4 is transmitted to the pin coupling (not shown) has been the tool holder 5 in the cylinder 4, the tip tool 1 that engages the tool holder 5 is rotated. Accordingly, the tip tool 1, as the circumferential known, so perforating, etc. of the workpiece to be described later by reciprocation and rotation [0013]
The intermediate part 2 is formed with a smaller diameter in the cylindrical part 2b closer to the striker 3 than in the cylindrical part 2a closer to the tip tool 1, and the intermediate part 2b is closer to the cylindrical part 2b closer to the striker 3. washers 1 0 on the outer peripheral position, the damper 11, washers 1 2 is fixed between the step 5b of the cylinder 4 the end face and the tool holder 5. The damper 11 constitutes a front shock absorber of the present invention, and the washer 10 and the washer 12 constitute a first washer and a second washer of the present invention, respectively.
[0014]
When the intermediate element 2 is moved i.e. retracted 3 side striking element has a front step portion 2c which faces the striking element 3 side between the diameter varies cylindrical portion 2a and the cylindrical portion 2b of the intermediate element 2 in the washers 1 0 abut, by the damper 11 a buffer member contacts the front step portion 2a through the washers 1 0, impact when the intermediate element 2 is moved to the 3 side striker is buffered. Further, the amount of movement of the striking element 3 side of the intermediate element 2 is restricted by the contact between the front step portion 2c and the washers 1 0.
[0015]
The engaging portion 2d on the outer periphery of the end of the striker 3 on the side of the intermediate member 2 has a smaller outer diameter than the small-diameter portion 2b and extends parallel to the axial direction of the cylinder 4, and engages with the engaging portion 2d on the inner periphery. the buffer member 23 is provided, having an outer periphery which engages the inner peripheral portion and the cylinder 4 inner circumference that engages with the engaging portion 2d, between the diameter of the intermediate element 2 varies cylindrical portion 2b and the engaging portion 2d A U-shaped washer 24 having a shape that abuts against the rear stepped portion 2e facing the striker 3 side and grips the buffer member 23 is disposed. The outer periphery of the U-shaped washer 24 has a shape protruding toward the annular member 6 as shown in the figure. The buffer member 23 that contacts the rear step portion 2a of the intermediate element 2 via the U-shaped washer 24 constitutes the rear buffer member of the present invention, and the U-shaped washer 24 constitutes the third washer of the present invention.
[0016]
As shown in FIG. 2, the annular member 6 is provided with an inner diameter portion 6a for gripping the buffer member 23 and protrusions 6b protruding outward (two locations in the figure). The projection 6b engages with the elongated holes 4a and 5a in the tool axis direction provided in the cylinder 4 and the tool holder 5, and the annular member 6 moves in the axial direction along the elongated holes 4a and 5a. The long holes 4a and 5a have dimensions longer than the amount of movement of the meson 2 in the longitudinal direction of the tool axis. The front end surface of the annular member 6 and the rear end surface of the U-shaped washer 24 are set to have a predetermined distance.
[0017]
The outer periphery of the tool holder 5 and the slide sleeves 8 are provided on the outer periphery of the cylinder 4 is provided Sly dos Lee Bed 7 and sleeves 2 5. The front end surface of the slide sleeves 8 abuts against the rear end surface of the projecting portion 6b of the annular member 6, the front end surface of the sliding sleeves 7 abuts the rear end face of the slide sleeves 8. Slide sleeves 7 is urged 1 side or forward tip tool by the spring 9, the slide sleeves 8, the circular member 6, meson 2 is also energized similarly 1 side tip tool that is forward. Between the slide sleeves 7 and sleeves 2 5 set to have a predetermined interval.
[0018]
State of FIG. 1 is a time of hitting operation, when pressing the tool bit 1 in the workpiece, meson 2, U-shaped washer 24, cushioning member 23, the annular member 6, the slide sleeves 8, the slide sleeves 7 The piston 17 is moved backward against the spring pressure, that is, backward . The impact during this striking movement circular member 6 is jump, annular member 6 further against the spring pressure, the slide sleeves 8, although the sliding sleeves 7 tends to move the piston 17 side, whereby the slide Three Bed 7 is restricted a movement amount by contacting the sleeves 2 5, at the same time the slide sleeves 8, since the amount of movement of the annular member 6 is also restricted, it is possible to suppress the bounce of the circular member 6. The spacing between the slide sleeves 7 and sleeves 2 5, the spacing and the circular member 6 and slots 4a between the annular member 6 and the striker 3, and set smaller than the spacing between the piston 17 side end surface of 5a Therefore, it is possible to prevent the annular member 6 from colliding with the end face of the striker 3 and the long holes 4a and 5a on the piston 17 side and being damaged.
[0019]
Although the impact force to by that the striker 3 side mesons 2 is provided with a cushioning member 23 so as not transmitted to the annular member 6 directly during the striking movement, and this cushioning member 23 sandwiching the circular member Between the 6-shaped washer 24 and the U-shaped washer 24, it is set so that the buffer member 23 has substantially the same distance as the compression amount that can maintain the predetermined life, and the deflection amount of the buffer member 23 can be regulated to prevent premature breakage. . Further, the inner peripheral portion of the U-shaped washer 24 is engaged with the engaging portion 2d of the intermediate element 2, the outer peripheral portion has a relationship to be engaged with the cylinder 4 inner circumference, U-shaped washer 24 meson It also has the effect of supporting 2 in the radial direction.
[0020]
Further, when an impact force to the striking member 3 side by the intermediate element 2 is applied during the striking movement, beginning at the same time the compression of the damper 11 when the spacing between the sliding sleeves 7 and sleeves 2 5 begins to close, the damper 11 is compressed By doing so, the impact force can be reduced. At this time, the distance between the slide sleeves 7 and sleeves 2 5 By setting larger than the amount of deflection of the damper 11, the damper 11 are in contact with sliding sleeves 7 and sleeves 2 5 after maximum compression and Become.
[0021]
Incidentally, the state shown in FIG. 1 is a state where the front step portion 2c of the intermediate element 2 is in contact with the damper 11 through the washers 1 0, in this state, the anti-tip tool 1 side of the slide sleeves 7 interval as described above is present between the end surface or the rear end face and the sleeves 2 5 of the tool bit 1 end face or forward end surface. Dimension A of the gap is set to be smaller than the dimension B of the distance between the 3-side rear surface of the striking element of the striker 3 end face rear and the circular member 6 mesons 2, Therefore batting Even if the annular member 6 bounces back to the striker 3 side due to the impact during the striking operation during operation , the impact due to the intermediate element 2 is buffered by the damper 11 and the buffer member 23, so that the annular member 6 is It does not collide with the piston 17 side end surfaces of the long holes 4a and 5a of the cylinder 4 and the tool holder 5, and the ring member 6 can be prevented from reaching the end of its life early.
[0022]
Slide sleeves 7 and sleeves 2 5 to end faces is configured to collide, slide sleeves 7 and sleeves 2 5 own life can be a relatively long life.
[0023]
When the end surface of the slide sleeves 7 collides with the end surface of the sleeves 2 5 is that the impact force to the ring member 6 via sliding sleeves 8 are intended to be transmitted, the impact force, co because it is buffered by the buffer member 23 provided between the the shaped washer 24 and the circular member 6, it is possible to improve the life of the annular member 6.
[0024]
The space between the striker 3 side surface of the annular member 6, i.e., the rear end surface, and the striker 3 side end surface of the intermediate member 2, i.e., the rear end surface , is from the rear step portion 2 e of the intermediate member 2 to the U-shaped washer 24 and the buffer member 23. Further, it is determined by the thickness dimension of the annular member 6 in the axial direction.
[0025]
Incidentally, the sleeves 2 5 as a regulating member moved or backward movement to one side anti tip tool is a member that is regulated by abutting the end face of the key member 26, for example of the cylinder 4 the outer periphery in the axial direction It may be a C-ring attached so as not to move. In the present embodiment protrudes, by a member of substantially the same shape slide sleeves 7 and sleeves 2 5, with so that attained a reduction in costs, in the outer peripheral direction on the end face portion of the opposite both And a spring 9 that is an urging means for urging the slide sleeves 7 and 8 toward the tip tool 1 between the protrusions. Incidentally, the projecting portion of the sliding sleeves 7 is also combine function for abutting the end of the slide sleeves 8.
[0026]
Further, in the above embodiment, the configuration result was although the slide sleeve by two members of the slide sleeves 7 and the slide sleeves 8, they may be composed of one member.
[0027]
From the above, by adopting the configuration as described above, it is possible to prevent the annular member 6 and the buffer member 23 from being damaged early, and as a result, it is possible to provide a stable hammer drill having a long life.
[0028]
According to the above-described embodiment, the front step portion 2 c abuts against the damper 11 via the washer 10 during the backward movement of the intermediate element 2, and after the shock is buffered by the damper 11, the rear step portion 2 e becomes the U-shaped washer 24. Since they come into contact with each other, the impact of the meson 2 received by the annular member 6 becomes sufficiently small. As a result, it is possible to prevent the annular member 6 from colliding with the piston side end surfaces of the long holes 4a and 5a of the striker 3 , the cylinder 4 and the tool holder 5 . Results long life as a stable hammer drill further, the inner and outer circumference of the U-shaped washer 24, by engaging the rear engagement portion 2d and the engagement with the inner periphery of the cylinder 4 mesons 2, the intermediate element 2 in the radial direction There is also a supporting effect.
[0029]
【The invention's effect】
According to the present invention, since the impact at the time of the impact operation is buffered by the front buffer member and then buffered by the rear buffer member, it is possible to prevent the annular member and the rear buffer member from being damaged early, and as a result, the hammer drill The effect of improving the durability can be obtained.
[Brief description of the drawings]
FIG. 1 is a longitudinal side view showing an embodiment of the hammer drill of the present invention.
FIG. 2 is an enlarged view showing an annular member.
[Explanation of symbols]
1 is a tip tool, 2 is an intermediate element, 2a is a cylindrical part, 2b is a cylindrical part, 2c is a front step part, 2d is an engagement part, 2e is a rear step part, 3 is a striker, 4 is a cylinder, 4a is long hole, 5 tool holder, 5a are long holes, the circular member is 6, 6a an inner diameter portion, 6b is protrusion, 7, 8 slide sleeves, spring, 10, 12 washers 9, 11 Damper (front cushioning member), 13 is a motor, 14 is a first gear, 15 is a crankshaft, 16 is a connecting rod, 16 is a piston, 18 is an air chamber, 19 is a breathing hole, 20 is a second gear, and 21 is a first gear. Ichikasa gear, the second bevel gear 22, 23 is a buffer member (rear cushioning member) 24 is U-shaped washer 25 is sleeves.

Claims (1)

A motor, a crankshaft that is rotated by the rotation of the motor , a cylinder that is rotated by the motor via a rotation transmission mechanism and that extends along the axial direction, and engages with the crankshaft; a piston reciprocating in the axial direction, is reciprocally retained in the axial direction of the cylinder in the cylinder, Ru is moved by the pressure of the air chamber of the formed cylinder between the front end surface of the piston striking element When a plurality of breathing holes provided in the cylinder in order to communicate with outside air communicating said air chamber is coupled to the cylinder and Rutotomoni cylinder arranged coaxially to rotate together with the cylinder, removably tip tool A tool holder to be held, and held in the tool holder or in the cylinder so as to be reciprocable in the axial direction of the cylinder. And hitting capable mesons ends after the tool is movably held in the axial direction before Symbol cylinder, closes the previous SL breathing hole when the front Symbol mesons is retracted moved a predetermined amount or more to the piston side, the mesons a slide sleeve to open the front Symbol breathing hole Ru is communicated ambient air communicating said air chamber when moved forward a predetermined amount or more to the tool bit side than the axial movement of the intermediate element to the cylinder and the tool holder outer periphery It is located in a long hole having a large dimension, has a protrusion that contacts the slide sleeve on the outer periphery of the cylinder and the tool holder, and is closer to the striker than a rear step portion located on the striker side of the intermediate A hammer drill comprising an annular member located on the outer periphery of the meson and a biasing means for constantly biasing the slide sleeve forward on the tip tool side,
At the front step located on the tip tool side of the meson when the meson moves backward
A front buffer member that abuts via the first washer; a second washer that abuts against the front end surface of the cylinder that is provided behind the front cushion member; and a front that is provided in front of the annular member. A rear cushioning member abutting on a rear step portion located on the striker side of the meson via a third washer, and the intermediate step of the mesonment after the front step of the meson abuts the front cushioning member during the backward movement of the meson A hammer drill characterized in that the rear stepped portion is in contact with the rear cushioning member .

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