Working machine

Abstract

To improve convenience of a working machine.SOLUTION: The impact tool includes an electric motor, a striker 60 reciprocated in a front-rear direction by a driving force of the electric motor, a hammer member 65 reciprocated between an impactable position where striking force is transmitted to a tip tool by being struck by the striker 60 on the front side in the front-rear direction and a non-impactable position where striking is not performed by being positioned on the front side of the striker 60 in the front-rear direction, and a hammer guide 66 with which the striker 60 abuts when the hammer member 65 is in the non-impactable position.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a work machine equipped with an impact unit that transmits an impact force to an end tool. [Background technology]

[0002] Patent Document 1 describes a hammer drill in which a tool bit can be struck by a striker via an intermediate element. The hammer drill described in Patent Document 1 is provided with a mechanism for preventing blank strikes to prevent the striker from striking blanks when no load is applied to the tool bit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-211370 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned Patent Document 1, the blank strike prevention mechanism is formed by a circular member that can engage with the intermediate member, a pair of slide portions that can slide on the outer periphery of the cylinder, and a biasing means that biases the slide portions toward the tool tip.

[0005] Therefore, the number of parts required for the blank strike prevention mechanism is large, which leads to an increase in the diameter and weight of the hammer drill, resulting in a decrease in convenience.

[0006] An object of the present invention is to improve the convenience of a work machine. [Means for solving the problem]

[0007] In one aspect of the present invention, a tool has a motor, an impact section that is moved back and forth in a first direction by the driving force of the motor, an intermediate section that is moved back and forth between a first position where the impact section is struck on one side of the first direction to transmit the impact force to the tool tip, and a second position that is located on one side of the first position in the first direction and is not struck by the impact section, and an abutment section that the impact section abuts when the intermediate section is in the second position, and at least one of the impact section and the abutment section is equipped with a conversion section that can convert the direction of the force transmitted from the impact section to the abutment section from the first direction to a second direction that intersects the first direction. [Effects of the Invention]

[0008] According to the present invention, the convenience of the work machine can be improved. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of the electric hammer of the first embodiment as seen from the left side. [Figure 2] 2 is an enlarged cross-sectional view of the striking unit and its surroundings in FIG. 1 during striking. [Figure 3] 2 is an enlarged cross-sectional view of the striking unit and its surroundings in FIG. 1 during blank striking. [Figure 4] FIG. 4 is an enlarged view of a portion A circled by a dashed line in FIG. [Figure 5] FIG. 5 is an enlarged view of a portion B circled by a dashed line in FIG. [Figure 6] FIG. 10 is an enlarged cross-sectional view of the striking unit and its surroundings in the first modified example during blank striking. [Figure 7] FIG. 10 is an enlarged cross-sectional view showing the electric hammer of the second embodiment (when striking). [Figure 8] FIG. 10 is an enlarged cross-sectional view showing the electric hammer of the second embodiment (during blank striking). [Figure 9] FIG. 9 is an enlarged view of a portion C circled by a dashed line in FIG. 8. [Figure 10] FIG. 10 is an enlarged view of a portion D circled by a dashed line in FIG. [Figure 11] FIG. 10 is an enlarged cross-sectional view of the periphery of the striking unit of the second modified example during blank striking. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0011] <First Embodiment> Fig. 1 is a cross-sectional view of the electric hammer of embodiment 1 as seen from the left side. Fig. 2 is an enlarged cross-sectional view of the periphery of the striking unit in Fig. 1 during striking. Fig. 3 is an enlarged cross-sectional view of the periphery of the striking unit in Fig. 1 during blank striking. Fig. 4 is an enlarged view of part A circled by a dashed line in Fig. 3. Fig. 5 is an enlarged view of part B circled by a dashed line in Fig. 4. Fig. 6 is an enlarged cross-sectional view of the periphery of the striking unit of modified example 1 during blank striking.

[0012] <Electric hammer> 1 to 3, a tool tip 11 is detachably attached to the electric hammer 10. The tool tip 11 is brought into contact with a workpiece (not shown) and the electric hammer 10 is operated with a load applied to the tool tip 11, whereby the tool tip 11 repeats striking motions at a predetermined cycle.

[0013] The tip tool 11 may be, for example, a so-called "bull point" formed in a tapered rod shape. This allows the electric hammer 10 to be used to perform drilling, chipping, and crushing operations on objects such as concrete and stone. The electric hammer 10 corresponds to the work machine of the present invention.

[0014] 1, the axial direction of the rotary shaft 31 of the electric motor 30 is defined as the up-down direction. The movement direction of the tool bit 11 is defined as the front-rear direction. Furthermore, the direction perpendicular to both the axial direction of the rotary shaft 31 (up-down direction) and the movement direction of the tool bit 11 (front-rear direction) (the direction into the paper of all the drawings) is defined as the left-right direction.

[0015] The front side in the front-rear direction corresponds to one side of the first direction in the present invention, and the rear side in the front-rear direction corresponds to the other side of the first direction in the present invention. Also, a direction that intersects with the front-rear direction and in which lines extend radially from the axis Ct of the tool bit 11 (hereinafter referred to as the radial direction) corresponds to the second direction in the present invention.

[0016] The electric hammer 10 has a housing 20 that forms the outer shell of the electric hammer 10. Inside the housing 20, an electric motor 30, a gear mechanism 40, a crankshaft 50, and a striking unit 60 are accommodated so that power can be transmitted between them.

[0017] <Electric motor> 1, the electric motor 30 has a rotary shaft 31. The rotary shaft 31 extends in the vertical direction of the electric hammer 10. In other words, the rotary shaft 31 extends in a direction perpendicular to the direction of movement of the tool bit 11. The rotary shaft 31 is rotated by supplying a drive current to the electric motor 30, and the rotational force of the rotary shaft 31 is transmitted to a gear mechanism 40 disposed above the electric hammer 10.

[0018] Specifically, a pinion gear 32 is integrally provided on the axially upper side of the rotary shaft 31, and the pinion gear 32 is meshed with the gear mechanism 40. Therefore, the gear mechanism 40 is driven by the rotary shaft 31.

[0019] Here, the electric motor 30 is a brushed electric motor, and a commutator 33 is integrally provided below the axial direction of the rotary shaft 31. A pair of carbon brushes (not shown) is in sliding contact with the outer periphery of the commutator 33. The electric motor 30 is driven to rotate when the operator presses a switch SW provided on the handle portion 21 while gripping the handle portion 21.

[0020] Here, the handle portion 21 forms part of the housing 20 and is hollow inside. A plurality of electrical wires LN are housed inside the handle portion 21, and these electrical wires LN electrically connect the switch SW, the electric motor 30, and the power cord CD to one another. The electric motor 30 corresponds to the motor in this invention.

[0021] <Gear mechanism> The gear mechanism 40 driven by the electric motor 30 includes a small diameter gear 41 and a large diameter gear 42 having a larger diameter than the small diameter gear 41. The small diameter gear 41 is meshed with the pinion gear 32 of the rotary shaft 31, and is rotated in accordance with the rotation of the pinion gear 32. The small diameter gear 41 is rotated at a slower speed and with a higher torque than the pinion gear 32.

[0022] Furthermore, the large diameter gear 42 is meshed with the small diameter gear 41 and rotates with the rotation of the small diameter gear 41. The large diameter gear 42 rotates at a slower speed and with higher torque than the small diameter gear 41. In this way, the gear mechanism 40 forms a reduction mechanism that decelerates the rotation of the rotary shaft 31 to increase the torque.

[0023] A crankshaft 50 is fixed by press fitting or the like to the center of rotation of large-diameter gear 42 on the output side of the reduction mechanism, and crankshaft 50 is rotated by large-diameter gear 42. A crankpin 51 is integrally provided on the axially lower side of crankshaft 50, and the rear side of a connecting rod 62 is rotatably attached to crankpin 51. A piston 63 is attached to the front side of connecting rod 62 in the longitudinal direction so as to be able to swing freely.

[0024] The driving force of the electric motor 30 is transmitted to the crankshaft 50 via the rotary shaft 31 and the gear mechanism 40. As the crankshaft 50 rotates, the connecting rod 62 and the piston 63 reciprocate in the front-to-rear direction inside the cylinder 61. In this way, the crankshaft 50 has the function of converting the rotational motion of the electric motor 30 into the linear motion of the piston 63.

[0025] <Strike unit> As shown in FIGS. 2 and 3, the striking unit 60 includes a cylinder 61, a connecting rod 62, a piston 63, a striker 64, a hammer member 65, and a hammer guide 66.

[0026] The cylinder 61 is made of, for example, a metallic cylindrical tube, and is fixed inside the longitudinal front side of the housing 20. A piston 63 is accommodated inside the cylinder 61 at the rear side in the axial direction so as to be able to reciprocate in the front-to-rear direction. Meanwhile, a striker 64 is accommodated inside the cylinder 61 at the front side in the axial direction so as to be able to reciprocate.

[0027] An air chamber AR is formed inside the cylinder 61 and between the piston 63 and the striker 64. The air chamber AR is contracted or expanded by the reciprocating movement of the piston 63 inside the cylinder 61, and in response to this, the striker 64 moves back and forth inside the cylinder 61. Therefore, the striker 64 strikes the hammer member 65 at a predetermined cycle, and the hammer member 65 strikes the bit 11 at a predetermined cycle.

[0028] Here, a first seal member SL1 made of a rubber O-ring or the like is attached to the piston 63. This prevents air from leaking from the air chamber AR to the rear side in the axial direction of the cylinder 61 via the piston 63. In addition, a second seal member SL2 made of a rubber O-ring or the like is attached to the rear side in the axial direction of the striker 64. This prevents air from leaking from the air chamber AR to the front side in the axial direction of the cylinder 61 via the striker 64.

[0029] Furthermore, a single first air hole 61a that communicates between the inside and outside of the cylinder 61 is provided in approximately the center of the axial direction of the cylinder 61. Furthermore, a plurality of second air holes 61b that communicate between the inside and outside of the cylinder 61 are provided in a portion of the cylinder 61 closer to the front than the center of the axial direction. Air that flows out from the inside of the cylinder 61 to the outside of the cylinder 61 through the first and second air holes 61a, 61b flows out to the outside of the housing 20 through the inside of the housing 20.

[0030] That is, in the axial direction of the cylinder 61, the air chamber AR is in a compressed state or a non-compressed state depending on the positions of the first seal member SL1 of the piston 63 and the second seal member SL2 of the striker 64 relative to the first air hole 61a and the second air hole 61b, respectively.

[0031] 2, when the electric hammer 10 "strikes," the bit 11 abuts against the workpiece, and the bit 11 is moved rearward in the front-to-rear direction. As a result, the striker 64 is moved rearward in the axial direction of the cylinder 61 via the hammer member 65, and the second seal member SL2 of the striker 64 is positioned rearward in the axial direction of the cylinder 61 relative to the second air hole 61b of the cylinder 61.

[0032] In this state, when the piston 63 is moved axially forward and the first seal member SL1 of the piston 63 passes over the first air hole 61a, the air chamber AR is compressed, and the striker 64 moves swiftly axially forward of the cylinder 61 and strikes the hammer member 65 (the tool bit 11).

[0033] Thus, the striking position P1 (see FIG. 2) of the hammer member 65, which is struck forward in the front-rear direction by the striker 64 and transmits the striking force to the bit 11, corresponds to the first position in the present invention.

[0034] Thereafter, the second seal member SL2 of the striker 64 passes over the second air hole 61b, the air chamber AR is in communication with the second air hole 61b, and the air chamber AR is in a non-compressed state. The piston 63 is also moved axially rearward, returning to the state shown in Fig. 2. By periodically repeating this operation, the bit 11 repeats the impact operation at a predetermined cycle (for example, 1200 reciprocations / min).

[0035] On the other hand, as shown in Fig. 3, when the electric hammer 10 is "blank striking," the load applied to the tool bit 11 from the workpiece is released, so the tool bit 11 and the hammer member 65 are moved further forward in the front-to-rear direction. Therefore, the tool bit 11 and the hammer member 65 are moved to the furthest position forward in the front-to-rear direction. At this time, the hammer member 65 hits the buffer material 68, and the impact is absorbed by the buffer material 68. Then, while the striker 64 hits the hammer guide 66, it cannot hit the hammer member 65.

[0036] In this way, the non-striking position P2 (see Figure 3) of the hammer member 65, which is located forward in the front-to-rear direction from the striking position P1 (see Figure 2) and is not struck by the striker 64, corresponds to the second position in the present invention.

[0037] That is, the hammer member 65 is reciprocally movable between a striking position P1 and a striking non-striking position P2 in the front-rear direction of the electric hammer 10. The hammer member 65 corresponds to the intermediate portion in the present invention.

[0038] When the hammer member 65 is located at the non-striking position P2, the striker 64 abuts against the hammer guide 66. The impact absorption function when the striker 64 abuts against the hammer guide 66 will be described later. The hammer guide 66 corresponds to the abutment portion in the present invention.

[0039] 3, the second seal member SL2 of the striker 64 passes over the second air hole 61b, and the air chamber AR is in communication with the second air hole 61b. Therefore, even if the piston 63 moves back and forth inside the cylinder 61, the air in the air chamber AR simply moves back and forth between the inside and outside of the cylinder 61 via the second air hole 61b, and the air chamber AR does not become compressed. Therefore, the striker 64 and the hammer member 65 are prevented from moving back and forth inside the cylinder 61, and the bit 11 is prevented from striking empty holes.

[0040] <Strike> The striker 64 is reciprocated in the front-rear direction by the driving force of the electric motor 30, and corresponds to the impact portion of the present invention. Specifically, as shown in Figures 2 to 4, the striker 64 has a first large diameter portion 64a and a second large diameter portion 64b, each having an outer diameter D1 that is slightly smaller than the inner diameter of the cylinder 61. In the axial direction of the striker 64, the first large diameter portion 64a is located on the front side, and the second large diameter portion 64b is located on the rear side.

[0041] A small diameter portion 64c having a smaller diameter than the first and second large diameter portions 64a, 64b is disposed between the first large diameter portion 64a and the second large diameter portion 64b along the axial direction of the striker 64. A second seal member SL2 is attached to the second large diameter portion 64b.

[0042] In this way, by providing the second seal member SL2 only on the second large diameter portion 64b and also providing the small diameter portion 64c, an increase in the sliding resistance of the striker 64 against the cylinder 61 is suppressed. This allows the striker 64 to reciprocate with good responsiveness in response to changes in the internal pressure of the air chamber AR.

[0043] Here, a circular rear flat surface SF1 that extends in a direction perpendicular to the front-to-rear direction is provided on the axial rear side of the striker 64. In contrast, a protrusion TP that tapers toward the bit 11 is integrally provided on the axial front side of the striker 64.

[0044] 4 and 5, the protrusion TP has an annular striker-side inclined surface 64d that is inclined with respect to the front-to-rear direction of the electric hammer 10. Specifically, the striker-side inclined surface 64d is formed so as to taper toward the front in the front-to-rear direction, and the inclination angle of the striker-side inclined surface 64d with respect to a line segment LE that is parallel to the axis Ct of the striker 64 is α degrees (approximately 45 degrees). Furthermore, the striker-side inclined surface 64d is provided over the entire circumferential area of ​​the striker 64.

[0045] When the electric hammer 10 is operated with the bit 11 separated from the workpiece, that is, when there is no load on the bit 11 from the workpiece (during blank striking), the striker-side inclined surface 64d comes into contact with and butts against the hammer-guide-side inclined surface 66d as shown in Figures 4 and 5. The striker-side inclined surface 64d corresponds to the striking-part-side inclined surface in the present invention.

[0046] Here, by setting the inclination angle of the striker-side inclined surface 64d with respect to the line segment LE parallel to the axis Ct of the striker 64 to approximately 45 degrees, damage to the hammer guide 66 is suppressed, and as shown in FIG. 5, the force F along the front-to-rear direction can be effectively dispersed in two directions: a first component force f1 along the front-to-rear direction and a second component force f2 along the radial direction.

[0047] However, if the inclination angle α of the striker-side inclined surface 64d with respect to the line segment LE parallel to the axis Ct of the striker 64 is less than 20 degrees, the striker 64 will forcefully push the hammer guide 66 outward in the radial direction, which may cause cracks or other early damage to the hammer guide 66. On the other hand, if the inclination angle α is greater than 70 degrees, the second component force f2 in the radial direction will become too small, making it impossible to sufficiently absorb the impact force.

[0048] Therefore, it is desirable that the inclination angle α degrees of the striker-side inclined surface 64d with respect to the line segment LE parallel to the axis Ct of the striker 64 be 20 degrees or more and 70 degrees or less.

[0049] Furthermore, a circular front flat surface SF2 extending in a direction perpendicular to the front-to-rear direction is provided on the axial front side of the striker 64 and at the top of the protrusion TP. Specifically, the front flat surface SF2 is disposed radially inward of the striker-side inclined surface 64d and has a smaller diameter than the rear flat surface SF1. Note that the front flat surface SF2 strikes the abutment portion 65c on the axial rear side of the hammer member 65 when the bit 11 strikes.

[0050] Furthermore, an annular flat surface SF3 extending in a direction perpendicular to the front-to-rear direction is provided on the axial front side of the striker 64 and radially outward of the striker-side inclined surface 64d. Here, in the axial direction of the striker 64, with the position of the striker-side inclined surface 64d as a reference, the front flat surface SF2 is located on the front side, and the annular flat surface SF3 is located on the rear side.

[0051] As described above, the protrusion TP includes, from its radially inner side, a circular front flat surface SF2 extending in a direction perpendicular to the front-to-rear direction, a striker-side inclined surface 64d arranged radially outward of the front flat surface SF2, and an annular flat surface SF3 arranged radially outward of the striker-side inclined surface 64d and extending in a direction perpendicular to the front-to-rear direction. Note that the front flat surface SF2 corresponds to the first orthogonal surface in this invention, and the annular flat surface SF3 corresponds to the second orthogonal surface in this invention.

[0052] Here, as shown in FIG. 4, in the radial direction of the striker 64, which is perpendicular to the front-to-rear direction, when a line segment D1 passes through the center of the striker 64, the proportion of the striker-side inclined surface 64d (W1+W1) on the line segment D1 is approximately 22% (≒(W1+W1)×100 / D1).

[0053] As a result, even if the striker 64 is slightly misaligned with respect to the hammer guide 66, the striker-side inclined surface 64d can reliably abut against the hammer-guide-side inclined surface 66d. Furthermore, the area of ​​the front flat surface SF2 that abuts against the abutment portion 65c of the hammer member 65 can be sufficiently secured, which in turn makes it possible to suppress uneven wear of the abutment portions of the striker 64 and the hammer member 65.

[0054] However, if (W1+W1)×100 / D1 is less than 3%, even a slight axial misalignment may cause the striker-side inclined surface 64d to not properly abut against the hammer-guide-side inclined surface 66d. On the other hand, if (W1+W1)×100 / D1 is greater than 80%, the front side of the protrusion TP becomes sharp, and there is a risk that the abutment portion 65c of the hammer member 65 may be damaged due to stress concentration during impact.

[0055] Therefore, in the radial direction of the striker 64, which is perpendicular to the front-rear direction, it is desirable that the proportion of the striker-side inclined surface 64d(W1+W1) on the line segment D1 passing through the center of the striker 64 be 3% or more and 80% or less. It is more desirable that the proportion of the striker-side inclined surface 64d(W1+W1) on the line segment D1 be 10% or more and 60% or less.

[0056] <Hammer parts> 2 and 3, the hammer member 65 is made of steel and is generally cylindrical, with the axial front side (the tool bit 11 side) of the hammer member 65 tapering to a point. The hammer member 65 includes a hammer body 65a slidably mounted on the hammer guide 66, and a hammer head 65b disposed on the axial front side of the hammer body 65a. An abutment portion 65c against which the front flat surface SF2 of the striker 64 abuts is provided on the axial rear side of the hammer body 65a.

[0057] The hammer head 65b is disposed inside a tool holder 67 that holds the tool bit 11. Specifically, the hammer head 65b reciprocates back and forth in the axial rear of the tool holder 67 in response to the striking action of the striker 64. A buffer 68 made of an elastic material such as rubber is housed inside the tool holder 67, and the hammer head 65b abuts against the buffer 68 when the hammer member 65 moves to the frontmost position during blank striking. This reduces the impact transmitted from the hammer member 65 to the housing 20.

[0058] The rear axial side of the tool bit 11 is accommodated in the axial front side of the tool holder 67 so as to be able to move back and forth freely. A tool holder 67a is provided on the axial front side of the tool holder 67, and the tool holder 67a functions as a stopper to prevent the tool bit 11 from falling out of the tool holder 67.

[0059] <Hammer Guide> 2 to 5, the hammer guide 66, which slidably holds the hammer member 65, is made of steel and has a generally cylindrical shape. Specifically, the hammer guide 66 includes a cylindrical main body portion 66a and a flange portion 66b.

[0060] A through-hole 66c extending in the front-rear direction of the electric hammer 10 is provided radially inside the cylindrical main body 66a, and a pair of O-rings OR (see FIG. 4) are fitted in the through-hole 66c. These O-rings OR slidably support the hammer main body 65a of the hammer member 65. In other words, the through-hole 66c guides the reciprocating movement of the hammer main body 65a via the pair of O-rings OR.

[0061] Here, the O-ring OR prevents dust and the like from entering the inside of the cylinder 61 from the axial front side of the hammer member 65. The O-ring OR also prevents scratches on the surface of the hammer main body 65a.

[0062] The through-hole 66c allows the hammer body 65a of the hammer member 65 to be inserted therethrough, but does not allow the striker 64 that strikes the hammer member 65 to be inserted therethrough. As a result, the striker 64 abuts against the hammer guide 66 when the electric hammer 10 is used for blank striking.

[0063] The flange portion 66b is disposed in approximately the center of the cylindrical main body portion 66a in the axial direction, protrudes radially outward from the cylindrical main body portion 66a, and is formed in a disk shape. The outer periphery of the flange portion 66b is slidable relative to the inner periphery of the housing 22. This allows the hammer guide 66 to move in the front-to-rear direction of the electric hammer 10 within the housing 22.

[0064] However, an annular first damper member 69 is disposed in front of the flange portion 66b. The first damper member 69 is attached to the housing 20 and restricts the forward movement of the hammer guide 66. On the other hand, an annular second damper member 70 is disposed in rear of the flange portion 66b. The second damper member 70 is attached to the housing 20 and restricts the rearward movement of the hammer guide 66. In other words, the flange portion 66b is sandwiched between the first damper member 69 and the second damper member 70 in the front-to-rear direction of the electric hammer 10.

[0065] As a result, when the striker 64 hits the hammer guide 66 from its rear side, the first damper member 69 is elastically deformed to absorb the impact. On the other hand, when the hammer member 65 hits the hammer guide 66 from its front side, the second damper member 70 is elastically deformed to absorb the impact. Therefore, when the striking unit 60 performs a striking operation, the impact transmitted to the housing 20 is alleviated.

[0066] 5, a striker abutment portion SA is integrally provided on the axial rear side of the cylindrical main body portion 66a and on the inner periphery of the cylindrical main body portion 66a, against which the protrusion TP of the striker 64 abuts. The striker abutment portion SA has an annular hammer guide-side inclined surface 66d that is inclined relative to the front-to-rear direction of the electric hammer 10.

[0067] Specifically, the hammer guide-side inclined surface 66d is inclined so that its inner diameter gradually increases toward the rear in the front-to-rear direction, thereby allowing the striker-side inclined surface 64d to abut against it and butt against it with a surface. Like the striker-side inclined surface 64d, the hammer guide-side inclined surface 66d has an inclination angle of α degrees (approximately 45 degrees) with respect to a line segment LE parallel to the axis Ct of the hammer guide 66. The hammer guide-side inclined surface 66d is provided over the entire circumferential area of ​​the cylindrical main body portion 66a.

[0068] Here, the striker-side inclined surface 64d and the hammer guide-side inclined surface 66d, which abut against each other at their surfaces, correspond to the conversion portion in the present invention. That is, the striker-side inclined surface 64d and the hammer guide-side inclined surface 66d can convert the direction of the force F transmitted from the striker 64 to the hammer guide 66 from the front-to-rear direction to a radial direction (the up-and-down direction in FIG. 5) that intersects with the front-to-rear direction.

[0069] The hammer guide side inclined surface 66d provided on the hammer guide 66 corresponds to the contact portion side inclined surface in this invention.

[0070] More specifically, the striker-side inclined surface 64d and the hammer-guide-side inclined surface 66d butt against each other at their surfaces, thereby dispersing the direction of the force F transmitted from the striker 64 to the hammer guide 66 into two directions: a first component force f1 directed forward in the front-to-rear direction, and a second component force f2 directed in a radial direction intersecting the front-to-rear direction. Note that the striker-side inclined surface 64d and the hammer-guide-side inclined surface 66d are inclined at α degrees (approximately 45 degrees) with respect to the front-to-rear direction of the electric hammer 10, so the magnitude of the first component force f1 and the magnitude of the second component force f2 are approximately the same (f1 ≈ f2).

[0071] As a result, when the electric hammer 10 is struck empty, the impact force from the striker 64 transmitted to the front side in the front-to-rear direction is weakened to the first component force f1 (half of the force F) and is absorbed by the first damper member 69 via the flange portion 66b. Therefore, while the transmission of the impact force to the worker is softened, early damage to other parts of the electric hammer 10 due to the impact force during empty striking is suppressed.

[0072] The first damper member 69 is provided between the hammer guide 66 and the housing 20 that houses the hammer guide 66, and prevents the hammer guide 66 from moving forward in the fore-and-aft direction when the striker 64 abuts against the hammer guide 66, and corresponds to the elastic member in the present invention.

[0073] 5, when the striker 64 abuts against the hammer guide 66, only the striker-side inclined surface 64d and the hammer-guide-side inclined surface 66d can abut against each other. Specifically, an annular recess 66e recessed toward the axial front side of the hammer guide 66 is provided on the axial rear side of the hammer guide 66 and radially inward of the hammer-guide-side inclined surface 66d. This prevents the top of the protrusion TP of the striker 64 from colliding with the hammer guide 66 inside the hammer guide 66.

[0074] In this way, the annular recess 66e is disposed on the rear side in the front-to-rear direction of the electric hammer 10, and has the function of preventing the striker 64 from contacting portions other than the hammer-guide-side inclined surface 66d when the striker-side inclined surface 64d of the striker 64 abuts against the hammer-guide-side inclined surface 66d. The annular recess 66e corresponds to the contact avoidance portion in this invention.

[0075] Furthermore, the contact portion between the striker-side inclined surface 64d and the hammer guide-side inclined surface 66d is moved radially inward of the striker 64 and the hammer guide 66, while the surface area of ​​the striker-side inclined surface 64d is made larger than the surface area of ​​the hammer guide-side inclined surface 66d. Therefore, when the striker-side inclined surface 64d and the hammer guide-side inclined surface 66d are in abutment against each other, an annular gap SP is formed between the axial rear end face TF of the hammer guide 66 and the annular flat surface SF3 of the striker 64. This prevents the annular flat surface SF3 of the striker 64 from colliding with the hammer guide 66.

[0076] 4, an annular receiving portion 66f is provided on the axial front side of the cylindrical main body portion 66a to receive the hammer head portion 65b (see FIGS. 2 and 3) of the hammer member 65 when the hammer member 65 moves rearward in the front-to-rear direction relative to the hammer guide 66. This transmits a striking force to the tool bit 11, and when the hammer member 65 returns to the axial rear side due to the reaction force at that time, the annular receiving portion 66f receives the impact force.

[0077] The impact force from the hammer member 65 is absorbed by the second damper member 70 via the flange portion 66b. This reduces the transmission of the impact force to the worker, while preventing other parts of the electric hammer 10 from being damaged early due to the impact force at the time of impact.

[0078] <Variation 1> Next, a first modified example of the electric hammer 10 will be described with reference to the drawings. Note that parts having the same functions as those of the electric hammer 10 described above are given the same reference numerals, and detailed description thereof will be omitted.

[0079] As shown in FIG. 6, an electric hammer (working machine) 80 according to the first modification has a tip tool 81 with a different shape from a tool holder 82 that holds the tip tool 81.

[0080] Specifically, as shown in FIG. 6, the tip tool 81 has an insertion portion 81a that is inserted into the tool holder 82, and an annular protrusion 81b that is integrally formed on the front side of the insertion portion 81a in the fore-and-aft direction and protrudes radially outward.

[0081] The tool holder 82 also includes a retaining tube 82a that holds the insertion portion 81a so that it can move back and forth in the front-to-back direction, a lever pin 83 that extends in the vertical direction perpendicular to the axial direction of the retaining tube 82a, and a pair of annular dampers 84 that elastically support the lever pin 83 in the front-to-back direction of the electric hammer 80.

[0082] In addition, the rear side of the lock lever 85, which is formed in an approximately C-shape, is rotatably attached to the lever pin 83, and when the lock lever 85 is closed as shown in Figure 6, the annular protrusion 81b of the tip tool 81 catches on the front side of the lock lever 85 in the front-to-back direction, thereby preventing the tip tool 81 from coming off.

[0083] In contrast, when the lock lever 85 is raised by pulling it toward the front in FIG. 6 and rotated relative to the lever pin 83, the annular protrusion 81b is released from its engagement with the lock lever 85, making it possible to remove or replace the tip tool 81.

[0084] Here, the lever pin 83 is inserted with some play into a pin insertion hole 82b provided on the front side in the front-rear direction of the tool holder 82. In addition, annular dampers 84 are arranged between the lever pin 83 and the pin insertion hole 82b, and above and below the lever pin 83 in the axial direction.

[0085] 6, when the tool bit 81 moves forward in the front-to-rear direction with force during blank striking with the electric hammer 80, the annular protrusion 81b hits the front side of the lock lever 85 in the front-to-rear direction. Then, the lock lever 85 tries to move the lever pin 83 forward, and at this time, the pair of annular dampers 84 are elastically deformed to absorb the impact.

[0086] As described above in detail, this embodiment includes the electric motor 30, the striker 64 that is reciprocated in the front-to-rear direction by the driving force of the electric motor 30, the hammer member 65 that is reciprocated between a striking position P1 where the striker 64 strikes the front side in the front-to-rear direction and transmits the striking force to the bit 11, and a non-striking position P2 that is located further forward in the front-to-rear direction than the striking position P1 and is not struck by the striker 64, and the hammer guide 66 against which the striker 64 abuts when the hammer member 65 is in the non-striking position P2, and the striker 64 and the hammer guide 66 are provided with a striker-side inclined surface 64d and a hammer guide-side inclined surface 66d that are able to convert the direction of the force F transmitted from the striker 64 to the hammer guide 66 from the front-to-rear direction to a radial direction intersecting the front-to-rear direction.

[0087] As a result, when the electric hammer 10 is used for blank strikes, the impact force from the striker 64 transmitted to the front side in the front-to-rear direction is converted into a second component force f2 in the radial direction and dispersed, and can be weakened to a first component force f1 in the front-to-rear direction, which is approximately half the magnitude of the force F. Therefore, the transmission of the impact force to the worker can be softened, and it is possible to effectively prevent other parts of the electric hammer 10 from being damaged early due to the impact force during blank strikes. This improves the convenience of the electric hammer 10.

[0088] Furthermore, according to this embodiment, the striker-side inclined surface 64d is provided on the striker 64, is inclined so as to taper toward the front side in the front-rear direction, and is brought into contact with the hammer guide 66.

[0089] As a result, the striker-side inclined surface 64d of the striker 64 can easily convert the direction of the force F into a radial direction that intersects with the front-rear direction.

[0090] Furthermore, according to this embodiment, the striker-side inclined surface 64d is inclined at an inclination angle α degrees (approximately 45 degrees) between 20 degrees and 70 degrees with respect to a line segment LE parallel to the axis Ct of the striker 64.

[0091] This makes it possible to effectively distribute the force F along the front-to-rear direction into two directions: a first component force f1 along the front-to-rear direction and a second component force f2 along the radial direction, while suppressing damage to the hammer guide 66.

[0092] Furthermore, according to this embodiment, in the radial direction of the striker 64, which is perpendicular to the front-to-rear direction, the proportion of the striker-side inclined surface 64d (W1+W1) on the line segment D1 passing through the center of the striker 64 is 3% or more and 80% or less.

[0093] This allows the striker-side inclined surface 64d to reliably abut against the hammer-guide-side inclined surface 66d even if the striker 64 is slightly misaligned with respect to the hammer guide 66. Furthermore, it is possible to ensure a sufficient area of ​​the front flat surface SF2 that abuts against the abutment portion 65c of the hammer member 65, thereby suppressing uneven wear and the like at the abutment portions of the striker 64 and the hammer member 65.

[0094] Furthermore, according to this embodiment, the hammer guide side inclined surface 66d is provided on the hammer guide 66, is inclined so that the inner diameter gradually increases toward the rear side in the front-rear direction, and is brought into contact with the striker 64.

[0095] As a result, the direction of the force F can be easily converted into a radial direction intersecting the front-rear direction by the hammer guide side inclined surface 66d of the hammer guide 66.

[0096] Furthermore, according to this embodiment, the hammer guide 66 is provided with an annular recess 66e on the rear side in the front-to-rear direction that prevents the striker 64 from contacting parts other than the hammer guide side inclined surface 66d when the striker 64 abuts against the hammer guide side inclined surface 66d.

[0097] This makes it possible to prevent the top of the protrusion TP of the striker 64 from colliding with the hammer guide 66 inside the hammer guide 66 .

[0098] Furthermore, according to this embodiment, the hammer guide 66 has a through hole 66c extending in the front-rear direction, and the hammer member 65 can be inserted into the through hole 66c, but the striker 64 cannot be inserted into the through hole 66c.

[0099] This allows the hammer guide 66 to have the function of holding the hammer member 65 straight along the axis Ct and the function of weakening the impact when the striker 64 hits it, thereby avoiding an increase in the number of parts.

[0100] Furthermore, according to this embodiment, the first damper member 69 is provided to restrain the hammer guide 66 from moving forward in the front-rear direction when the striker 64 abuts against the hammer guide 66.

[0101] As a result, when the striker 64 hits the rear side of the hammer guide 66, the first damper member 69 is elastically deformed, and is therefore able to absorb the impact.

[0102] <Embodiment 2> Next, an electric hammer (working machine) 90 according to a second embodiment will be described with reference to the drawings. Note that parts having the same functions as those in the first embodiment described above are given the same reference numerals, and detailed description thereof will be omitted.

[0103] Fig. 7 is an enlarged cross-sectional view showing the electric hammer of embodiment 2 (during impact). Fig. 8 is an enlarged cross-sectional view showing the electric hammer of embodiment 2 (during blank impact). Fig. 9 is an enlarged view of part C circled by a dashed line in Fig. 8. Fig. 10 is an enlarged view of part D circled by a dashed line in Fig. 9. Fig. 11 is an enlarged cross-sectional view of the periphery of the impact unit of modified example 2 during blank impact.

[0104] As shown in Figures 7 to 10, the electric hammer 90 of embodiment 2 differs from the electric hammer 10 of embodiment 1 (see Figures 2 to 5) only in the shapes of the striker (striking portion) 91, hammer member (middle portion) 92, and hammer guide (contact portion) 93.

[0105] Specifically, the striker 91 includes a striker body 91a equipped with a large-diameter seal SL3, and a protrusion TP tapering toward the tool bit 11. As in the first embodiment, the protrusion TP includes, from its radially inner side, a front flat surface SF2, a striker-side inclined surface 64d, and an annular flat surface SF3.

[0106] However, in the second embodiment, the striker-side inclined surface 64d is formed so as to taper toward the front in the fore-and-aft direction, and is inclined at β degrees (approximately 30 degrees) with respect to the line segment LE parallel to the axis Ct of the striker 91.

[0107] In addition, in the radial direction of the striker 91, which is perpendicular to the front-to-rear direction, the proportion of the striker-side inclined surface 64d (W2+W2) on the line segment D2 passing through the center of the striker 91 is approximately 27% (≒(W2+W2)×100 / D2).

[0108] The hammer member 92 is made of steel and has a generally cylindrical shape, and includes a hammer body 65a and a hammer head 92b. The hammer body 65a is slidably inserted into a through-hole 66c of the hammer guide 93. A pair of small diameter seals SL4 is attached to the outer periphery of the hammer head 92b, and the hammer head 92b is slidably provided inside the tool holder 67 via the pair of small diameter seals SL4.

[0109] The hammer guide 93 is made up of an annular first guide member 93a arranged on the front side of the electric hammer 90 in the front-to-rear direction, an annular second guide member 93b arranged on the rear side of the electric hammer 90 in the front-to-rear direction, and an annular damper (elastic member) 93c arranged between the first guide member 93a and the second guide member 93b along the front-to-rear direction of the electric hammer 90. The first and second guide members 93a and 93b are made of steel, and the damper 93c is made of rubber.

[0110] An annular receiving portion 66f is provided on the axial front side of the first guide member 93a, and a striker abutment portion SA is provided on the axial rear side of the second guide member 93b. As described above, the hammer guide 93, which is made up of three parts, the first and second guide members 93a and 93b, and the damper 93c, has a structure in which the damper 93c is located approximately in the center in the axial direction. This eliminates the flange portion 66b (see FIG. 4) and the first and second damper members 69 and 70, which had separate functions and were necessary in the first embodiment.

[0111] Here, the hammer guide side inclined surface 66d forming the striker abutment portion SA is inclined at β degrees (approximately 30 degrees) with respect to the line segment LE parallel to the axis of the hammer guide 93, similar to the striker side inclined surface 64d.

[0112] As a result, when the striker 91 hits the hammer guide 93 (second guide member 93b), as shown in Figure 10, the striker-side inclined surface 64d and the hammer-guide-side inclined surface 66d distribute the direction of the force F transmitted from the striker 91 to the hammer guide 93 into two directions: a first component force f3 directed forward in the front-to-rear direction, and a second component force f4 directed in a radial direction intersecting the front-to-rear direction.

[0113] However, in the second embodiment, since the inclination angle of the striker-side inclined surface 64d and the hammer-guide-side inclined surface 66d is approximately 30 degrees, the magnitude of the second component force f4 is greater than the magnitude of the first component force f3 (f3 <f4)。

[0114] The damper 93c has the functions of the first and second damper members 69 and 70 (see FIG. 4) in Embodiment 1. Specifically, when the striker 91 hits the second guide member 93b of the hammer guide 93 from the rear side in the front-to-rear direction, and when the hammer member 92 hits the first guide member 93a of the hammer guide 93 from the front side in the front-to-rear direction, the damper 93c is elastically deformed to absorb the impact.

[0115] <Variation 2> As shown in Fig. 11, in the electric hammer 100 according to the second modification, the structure of the striking unit 60, which is the main component thereof, is the same as that of the electric hammer 90 described above. Also, in the electric hammer 100 according to the second modification, the structure of the bit and the surrounding area of ​​the tool holder that holds it is the same as that of the first modification of the first embodiment described above (see Fig. 6). In other words, the electric hammer 100 according to the second modification is a combination of the structure of the electric hammer 90 (see Fig. 7) and the structure of the first modification (see Fig. 6), and a detailed description thereof will be omitted.

[0116] The second embodiment configured as above can also achieve the same effects as the first embodiment described above.

[0117] The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications are possible without departing from the spirit of the present invention. For example, in the above-described embodiments, the striker 64, 91 and the hammer guide 66, 93 are provided with the striker-side inclined surface 64d and the hammer guide-side inclined surface 66d as conversion portions, respectively. However, the present invention is not limited to this, and at least one of the striker 64, 91 and the hammer guide 66, 93 may be provided with an inclined surface.

[0118] Furthermore, the material, shape, dimensions, number, installation location, etc. of each component in each of the above-described embodiments are arbitrary as long as they can achieve the present invention, and are not limited to the above-described embodiments. [Explanation of symbols]

[0119] 10...electric hammer (work machine), 11...tip tool, 20...housing, 21...handle portion, 22...housing, 30...electric motor (motor), 31...rotating shaft, 32...pinion gear, 33...commutator, 40...gear mechanism, 41...small diameter gear, 42...large diameter gear, 50...crankshaft, 51...crankpin, 60...striking unit, 61...cylinder, 61a...first air hole, 61b...second air hole, 62...connecting rod, 63...piston, 64...striker (striking portion), 64a...first large diameter portion, 64b...second large diameter portion , 64c...small diameter portion, 64d...striker side inclined surface (striking portion side inclined surface, conversion portion), 65...hammer member (intermediate portion), 65a...hammer body, 65b...hammer head, 65c...butting portion, 66...hammer guide (contact portion), 66a...cylindrical body portion, 66b...flange portion, 66c...through hole, 66d...hammer guide side inclined surface (contact portion side inclined surface, conversion portion), 66e...annular recess (contact avoidance portion), 66f...annular receiving portion, 67...tool holder, 68...buffer material, 69...first damper member (elastic member), 70...second damper member, 80...electric Hammer (work machine), 81... tool tip, 81a... insertion portion, 81b... annular protrusion, 82... tool holder, 82a... retaining tube, 82b... pin insertion hole, 83... lever pin, 84... annular damper, 85... lock lever, 90... electric hammer (work machine), 91... striker (impact portion), 91a... striker body, 92... hammer member (intermediate portion), 92b... hammer head, 93... hammer guide (contact portion), 93a... first guide member, 93b... second guide member, 93c... damper (elastic member), 100... electric hammer, AR... air chamber , CD...power cord, Ct...axis, F...force, LE...line segment, LN...electrical wiring, OR...O-ring, P1...strike position (first position), P2...non-strike position (second position), SA...strike abutment part, SF1...rear flat surface, SF2...front flat surface (first orthogonal surface), SF3...annular flat surface (second orthogonal surface), SL1...first seal member, SL2...second seal member, SL3...large diameter seal, SL4...small diameter seal, SP...annular gap, SW...switch, TF...end face, TP...projection, f1,f3...first component of force, f2,f4...second component of force

Claims

1. A motor; a striking unit that is reciprocated in a first direction by the driving force of the motor; an intermediate portion that reciprocates between a first position where the intermediate portion is struck by the striking portion in one direction to transmit the striking force to the bit, and a second position that is located on the one side of the first direction relative to the first position and is not struck by the striking portion; a contact portion with which the striking portion comes into contact when the intermediate portion is in the second position; and At least one of the hitting portion and the contact portion includes a conversion portion that converts the direction of a force transmitted from the hitting portion to the contact portion from the first direction to a second direction that intersects with the first direction. Work equipment.

2. the conversion portion is provided on the hitting portion, the conversion portion is inclined so as to taper toward one side in the first direction, and includes a hitting portion-side inclined surface that abuts against the abutment portion, The work machine according to claim 1 .

3. The hitting portion-side inclined surface is inclined at an angle of 20 degrees or more and 70 degrees or less with respect to a line segment parallel to the axis of the hitting portion. The work machine according to claim 2.

4. In a radial direction of the hitting portion that is perpendicular to the first direction, the proportion of the hitting portion-side inclined surface on a line segment that passes through the center of the hitting portion is 3% or more and 80% or less. The work machine according to claim 2.

5. The hitting portion is on one side in the first direction. a circular first orthogonal surface extending in a direction orthogonal to the first direction; the hitting portion side inclined surface is an annular surface disposed radially outward of the first orthogonal surface; a second orthogonal surface that is annular and disposed radially outward of the hitting portion-side inclined surface and extends in a direction orthogonal to the first direction; Equipped with A work machine according to any one of claims 2 to 4.

6. the conversion portion is provided on the contact portion, is inclined so that an inner diameter thereof gradually increases toward the other side in the first direction, and includes a contact portion-side inclined surface that contacts the striking portion. The work machine according to claim 1 .

7. the abutment portion includes a contact avoidance portion on the other side in the first direction that prevents the impact portion from contacting a portion other than the abutment portion-side inclined surface when the impact portion abuts the abutment portion-side inclined surface. The work machine according to claim 6.

8. the abutment portion has a through hole extending in the first direction, The intermediate portion can be inserted into the through hole, but the striking portion cannot be inserted into the through hole. The work machine according to claim 1 .

9. an elastic member that prevents the contact portion from moving to one side in the first direction when the striking portion contacts the contact portion; The work machine according to claim 1 .

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