Impact tool

Abstract

The present application provides a kind of impact tool.Hammer drill (1) has motor, tool holder (23), drive mechanism (30), the 1st intermediate shaft (80) and drive mechanism housing area (T) in shell (2), wherein, the tool holder is cylindrical and its top end can install tool head;The drive mechanism can impact tool head;The 1st intermediate shaft is arranged in drive mechanism, and it is rotated by the rotation of the output shaft of motor;Drive mechanism housing area is in sealed state in shell with drive mechanism is housed in drive mechanism housing area.Form air release path (77) in the inside of the 1st intermediate shaft, the air release path is used to release the air in drive mechanism housing area to the outside of drive mechanism housing area, and the through hole (80a) that becomes the entrance of air release path is formed on the outer circumferential surface of the 1st intermediate shaft.Accordingly, the pressure that rises in drive mechanism housing area due to the heat generation of drive mechanism can be effectively released.

Description

Technical Field

[0001] This invention relates to an impact tool such as a hammer drill. Background Technology

[0002] Impact tools such as hammer drills have a tool holder within a housing that allows a tool bit to be mounted at the top. An inner housing, which supports the tool holder and the output shaft of a motor, houses a drive mechanism that impacts (hammers) the tool bit in a sealed state. As disclosed in Patent Document 1, a drive mechanism is known that includes: a piston (including a piston cylinder) that reciprocates; a hammer that is linked to the reciprocating motion of the piston via an air chamber; and a power conversion mechanism that converts the rotation of the output shaft into the reciprocating motion of the piston.

[0003] In this type of impact tool, when the drive mechanism heats up due to the impact action, the pressure within the drive mechanism housing area rises. This disrupts the pressure balance between the drive mechanism housing area and the air cavity, potentially causing the hammer to move abnormally in a straight line, resulting in poor impact. To suppress this poor impact, Patent Document 1 employs a pressure adjustment channel. This pressure adjustment channel is formed by inserting a cylindrical member into a bottomed hole located at the rear end of the rotating shaft. The inlet of the pressure adjustment channel is formed inside the inner housing between the rear end of the rotating shaft and the cylindrical member. The outlet of the pressure adjustment channel is formed at the top of the cylindrical member and protrudes to the outside of the inner housing. Therefore, when the air inside the inner housing expands, causing the internal pressure to rise, the air inside the inner housing is discharged to the outside of the inner housing via the pressure adjustment channel, thereby releasing the pressure.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Publication No. 4461062 Summary of the Invention

[0007] [The technical problem that the invention aims to solve]

[0008] In the impact tool of Patent Document 1, the inlet of the pressure adjustment channel is formed in a narrow space between the bearing supporting the rotating shaft and the retaining ring and the inner surface of the inner housing. Therefore, when lubricating oil enters this space, it may block the pressure adjustment channel and prevent air from being released to the outside.

[0009] Therefore, the object of the present invention is to provide an impact tool that can effectively release the pressure rising in the drive mechanism housing area due to the heat generated by the drive mechanism.

[0010] [Technical solutions used to solve technical problems]

[0011] To achieve the above objectives, the present invention provides an impact tool, characterized in that,

[0012] The housing contains a motor, a tool holder, a drive mechanism, a rotating shaft, and a drive mechanism housing area.

[0013] The tool holder is cylindrical, and a tool head can be installed at its top.

[0014] The drive mechanism can impact the tool head;

[0015] The rotating shaft is disposed on the drive mechanism and rotates by the rotation of the output shaft of the motor;

[0016] The drive mechanism receiving area is sealed within the housing to house the drive mechanism.

[0017] An air release path is formed inside the rotating shaft to release air from the drive mechanism housing area to the outside of the drive mechanism housing area, and the inlet of the air release path is formed on the outer peripheral surface of the rotating shaft.

[0018] Invention Effects

[0019] According to the present invention, an inlet for an air release path is formed on the outer circumferential surface of the rotating shaft. Therefore, by means of centrifugal force, lubricating oil within the drive mechanism housing area is less likely to enter the air release path. Thus, the pressure rising within the drive mechanism housing area due to heat generated by the drive mechanism can be effectively released. Attached Figure Description

[0020] Figure 1 This is a three-dimensional view observed from behind the hammer drill.

[0021] Figure 2 This is a central longitudinal section view of a hammer drill.

[0022] Figure 3 yes Figure 2 An enlarged view of the drive mechanism section.

[0023] Figure 4 yes Figure 3 AA sectional view.

[0024] Figure 5 It is an exploded three-dimensional view of the outer shell, motor housing, and inner housing.

[0025] Figure 6 This is an exploded three-dimensional view of the inner shell.

[0026] Figure 7yes Figure 3 BB cross-sectional view.

[0027] Figure 8 This is an enlarged front view omitting the outer shell, inner shell, and motor housing.

[0028] Figure 9 This is an enlarged rear view of the outer casing.

[0029] Figure 10 yes Figure 8 FF sectional view (with outer shell).

[0030] Figure 11 yes Figure 3 CC section view.

[0031] Figure 12 yes Figure 7 DD sectional view.

[0032] Figure 13 yes Figure 7 EE sectional view.

[0033] Figure 14 This is a three-dimensional exploded view of the first intermediate axis section.

[0034] Figure 15 yes Figure 11 GG cross-sectional view.

[0035] Figure 16 This is a partial bottom view of the outer shell.

[0036] Explanation of reference numerals in the attached figures

[0037] 1: Hammer drill; 2: Housing; 3: Outer shell; 4: Motor housing; 5: Handle housing; 6: Connecting part; 7: Motor housing; 8: Screw; 9: Motor; 10: Output shaft; 21: Front cylinder; 22: Rear cylinder; 23: Tool holder; 30: Drive mechanism; 31: Rotation / impact action part; 32: Rotation / impact switching part; 33: Piston cylinder; 34: Hammer; 40: Inner housing; 41: Front housing; 42: Rear housing; 42a: Retaining recess; 42b: Peripheral wall; 43: Bearing retaining part; 44: Main body; 45: Upper through hole; 46: Sliding bearing; 47: Lower through hole; 47a: Groove; 47b: Inner circumferential surface; 49: O-ring; 50: Inner rib; 52: Outer rib; 54: Partition wall; 55: Front side 56: Lubricating oil chamber; 58: Rear lubricating oil chamber; 59: Front exhaust port; 60, 69: Notch; 68: Rear flange; 70: Threaded fastening part; 71: Threaded boss; 72: Internal thread part; 73: Circular recess; 76: Release hole; 77: Air release path; 80: First intermediate shaft; 80a: Through hole; 80b: Shaft hole; 81: Second intermediate shaft; 84: First gear; 86: Second gear; 88: First clutch; 90: Front engaging part; 90a: Claw; 91: Locking ring; 92: Anti-rotation plate; 92a: Claw; 97: Third gear; 98: Boss sleeve; 104: Second clutch; 109: Mode switching mechanism; 116: Switching knob; T: Drive mechanism receiving area; B: Tool head. Detailed Implementation

[0038] In one embodiment of the invention, the air release path inlet can also be formed by an orthogonal through-hole penetrating the rotating shaft. According to this structure, air can enter from both ends of the through-hole, ensuring that air enters from the other end even if one end is blocked by lubricating oil.

[0039] In one embodiment of the invention, a bearing supporting a rotating shaft may be provided within the drive mechanism housing area, and the outlet of the air release path may be formed on the opposite side of the drive mechanism housing area, across the bearing, in the axial direction of the rotating shaft. According to this structure, the air release path can be formed over a shorter distance in the axial direction of the rotating shaft.

[0040] In one embodiment of the invention, the bearing may also be a bearing with a seal. This structure reduces the likelihood of lubricating oil flowing from the bearing into the air release path.

[0041] In one embodiment of the invention, the inlet of the air release path can also be configured at the middle portion in the axial direction of the rotating shaft. According to this structure, lubricating oil within the drive mechanism housing area is less likely to enter from the inlet.

[0042] In one embodiment of the invention, a spline portion may be formed on the rotating shaft, and a clutch for switching operating modes may be slidably engaged with the spline portion. An inlet for the air release path may be located in the spline portion. According to this structure, the rotating spline teeth agitate the lubricating oil, appropriately preventing lubricating oil from entering the inlet.

[0043] In one embodiment of the invention, the drive mechanism receiving area may be formed by an inner housing disposed within a housing, having a retaining recess for holding the bearing, and an annular peripheral wall portion protruding toward the drive mechanism receiving area around the retaining recess. According to this structure, lubricating oil is less likely to flow along the inner surface of the inner housing and enter the retaining recess.

[0044] In one embodiment of the invention, a gear adjacent to the peripheral wall portion in the axial direction may be provided on the rotating shaft. With this structure, the rotating gear agitates the lubricating oil, thus appropriately preventing lubricating oil from entering the gap between the gear and the peripheral wall portion.

[0045] In one embodiment of the invention, the drive mechanism may have a rotating action part for rotating the tool holder, and a rotating shaft for transmitting rotation to the tool holder and a rotating shaft for impacting the tool head, with the rotating shaft having an inlet for forming an air release path serving as the rotating shaft for transmitting rotation. According to this structure, an air release path can be easily formed.

[0046] [Example]

[0047] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0048] (A brief explanation of hammer drills)

[0049] Figure 1 This is a three-dimensional diagram representing an example of a hammer drill. Figure 2 This is a central longitudinal section view of a hammer drill. Figure 3 yes Figure 2 An enlarged view of the drive mechanism section. Figure 4 yes Figure 3 AA sectional view.

[0050] The hammer drill 1 has a housing 2 that forms the outer contour. The housing 2 has an outer housing 3 on the front side, a motor housing 4 behind the outer housing 3, and a handle housing 5 behind the motor housing 4.

[0051] The motor housing 4 has a quadrilateral connecting portion 6 on the front side (viewed from the front) and a cylindrical motor housing portion 7 on the rear side. Also, Figure 5As shown, the connecting part 6 is connected to the outer casing 3 from the front via four screws 8, 8... at its four corners when viewed from the front. The motor 9 is housed in the motor housing 7 with the output shaft 10 facing forward.

[0052] The handle housing 5 is mounted outside the motor housing 7 from the rear and is movable relative to it in the front-to-back direction. The handle housing 5 is pushed to the rearward position by means of the anti-vibration mechanism of the coil spring 11.

[0053] A downwardly extending handle 12 is formed at the rear end of the handle housing 5. A switch 13, which causes the trigger 14 to protrude forward, is housed within the handle 12. A power cord 15 is connected to the switch 13. The power cord 15 extends from the lower end of the handle 12. Multiple air inlets 16, 16... extending in the front-rear direction are formed on the left and right side surfaces of the handle 12, respectively. The left and right air inlets 16 are arranged facing each other across the axis of the output shaft 10.

[0054] The output shaft 10 of the motor 9 protrudes into the housing 3 through the connecting portion 6. A pinion 17 is formed at the front end of the output shaft 10. A fan 18 is fixed to the output shaft 10 inside the connecting portion 6. A baffle 19 is fixed inside the connecting portion 6 behind the fan 18. Multiple rear exhaust ports 20, 20... are formed on the lower and right side surfaces of the connecting portion 6 on the radially outer side of the fan 18.

[0055] The outer casing 3 has a front cylindrical portion 21 and a rear cylindrical portion 22. The front cylindrical portion 21 is a cylindrical shape with a circular cross-section extending forward. The diameter of the rear cylindrical portion 22 is larger than that of the front cylindrical portion 21, and it appears as a hexagonal cylindrical shape when viewed from the main view. The front cylindrical portion 21 is positioned off-center above the rear cylindrical portion 22.

[0056] A cylindrical tool holder 23 is coaxially housed within the front cylindrical portion 21. The front end of the tool holder 23 protrudes forward from the front cylindrical portion 21. At the front end of the front cylindrical portion 21, a bearing 24 is provided to support the front portion of the tool holder 23. In front of the bearing 24, an oil seal 25 is provided to seal the space between the front cylindrical portion 21 and the tool holder 23.

[0057] An operating sleeve 26 is provided at the front end of the tool holder 23, which protrudes from the front cylinder 21. The operating sleeve 26 is provided for attaching and removing the tool head B from the top of the tool holder 23. A side handle 27 is installed at the front end of the front cylinder 21.

[0058] A drive mechanism 30 is provided inside the outer casing 3. The drive mechanism 30 has a rotation / impact action part 31 and a rotation / impact switching part 32 behind it.

[0059] The rotating / impact actuating unit 31 includes a tool holder 23, a piston cylinder 33, a hammer 34, and a striker 35. The piston cylinder 33 has an open front end and is housed in the rear of the tool holder 23 in a reciprocating manner. The hammer 34 is housed in the piston cylinder 33 in a reciprocating manner through an air cavity 36. The striker 35 is housed in the tool holder 23 in a reciprocating manner in front of the hammer 34. The tool holder 23 communicates with the front cylinder portion 21 through a plurality of through holes 37, 37. The rear of the tool holder 23 protrudes into the rear cylinder portion 22. Inside the rear cylinder portion 22, a gear 38 with a torque limiter is provided on the outer periphery of the tool holder 23.

[0060] An inner housing 40 is housed within the connecting portion 6 and the rear cylinder portion 22. The inner housing 40 supports the rear of the tool holder 23 on the rear side of the gear 38. A rotation / impact switching unit 32 is housed within the inner housing 40. By operating the switching knob 116 located on the lower surface of the rear cylinder portion 22, the rotation / impact switching unit 32 switches operating modes to transmit the rotation of the output shaft 10 to the rotation / impact actuation unit 31.

[0061] (Description of the inner shell)

[0062] The inner housing 40 is divided into two parts in the front-to-back direction, having a metal front housing 41 and a resin rear housing 42.

[0063] For example Figure 6 As shown, the front housing 41 has a bearing retainer 43 on the front side and a main body 44 on the rear side.

[0064] The bearing retaining part 43 is one size smaller than the rear cylinder part 22, and appears hexagonal when viewed from the front. Also, Figure 7 As shown, the bearing retainer 43 has an upper through hole 45 at the upper center. The rear part of the tool holder 23 is inserted into the upper through hole 45. The sliding bearing 46 supporting the rear part of the tool holder 23 is held in the upper through hole 45. On the lower left side of the upper through hole 45, a lower through hole 47 with a diameter smaller than the upper through hole 45 is formed.

[0065] A groove 48 is formed covering the entire circumference of the outer side of the sliding bearing 46 and the outer peripheral surface of the bearing retainer 43. An O-ring 49 is held in the groove 48. The O-ring 49 presses against the inner peripheral surface of the rear cylinder 22 to seal between the rear cylinder 22 and the bearing retainer 43. Therefore, the space between the outer shell 3 and the inner shell 40 is divided by the O-ring 49. On the front side of the O-ring 49, the space between the tool holder 23 and the outer shell 3 is sealed by an oil seal 25.

[0066] An inner rib 50 is formed on the front surface of the bearing retainer 43, facing forward. Also, Figure 8As shown, the inner rib 50, when viewed from the front, is shaped like an arc, surrounding the lower half of the gear 38 protruding from the upper through-hole 45. The front end of the inner rib 50 overlaps with the gear 38 radially. However, the left side of the inner rib 50 forms a semi-circular portion 51 that surrounds the lower through-hole 47 from the outside. The inner rib 50 divides the front surface of the bearing retainer 43, which is surrounded by the O-ring 49, vertically. The left and right ends of the inner rib 50 form inclined portions 50a, 50a that recede upwards. The front end of the middle portion of the inner rib 50 is located at the foremost position relative to the bearing retainer 43.

[0067] On the other hand, on the outer casing 3, on the front inner surface of the rear cylinder 22, such as Figure 9 As shown, an outer rib 52 is formed that protrudes rearward from the inner rib 50 of the bearing retaining portion 43. The outer rib 52 protrudes to the underside of the gear 38 in the assembled state of the inner housing 40, and is deformed at its rear end by being pushed by the front end of the inner rib 50, thereby forming a rib (so-called a crushing rib) tightly against the inner rib 50. The outer rib 52 is formed in a mirror-symmetrical manner with the inner rib 50 from front to back, and has a semi-circular portion 53 on the left side facing the semi-circular portion 51. Figure 4 As shown, the upper ends 52a, 52a of the left and right ends of the outer rib 52 protrude forward and abut against the front surface of the bearing retainer 43. The rear edges of the upper ends 52a, 52a have an inclined shape that advances downward, consistent with the inclined portions 50a, 50a of the left and right ends of the inner rib 50.

[0068] Therefore, when the inner shell 40 is assembled onto the outer shell 3, as... Figure 10 As shown, a partition wall 54 is formed by the mating of the outer rib 52 and the inner rib 50. Therefore, inside the outer casing 3, the space in front of the O-ring 49 is divided vertically by the partition wall 54. The upper side of the partition wall 54 is a front lubricating oil cavity 55 separated by the oil seal 25 and the O-ring 49. The front lubricating oil cavity 55 is connected to the rear lubricating oil cavity 56 inside the inner casing 40 through the lower through hole 47, etc. The front lubricating oil cavity 55 and the rear lubricating oil cavity 56 form the drive mechanism receiving area (hereinafter referred to as the "receiving area") T.

[0069] The main body 44 is slightly smaller than the bearing retaining part 43, and is hexagonal in shape when viewed from the front. Multiple heat dissipation fins 57, 57... are respectively erected on the left and right side surfaces of the main body 44. Each heat dissipation fin 57 is formed extending vertically and is erected at predetermined intervals along the front-to-back direction. Figure 11As shown, the outer edge of each heat dissipation blade 57 is close to the inner surface of the rear cylinder 22. On the outer side of the protruding direction of the heat dissipation blade 57, a plurality of front exhaust ports 58, 58... extending in the front-rear direction are formed on the left and right side surfaces of the rear cylinder 22, respectively. The left and right front exhaust ports 58 are arranged so that they face each other across the axis of the output shaft 10 when viewed from above.

[0070] A front flange 59, which appears as a quadrilateral when viewed from the front, is formed at the rear end of the main body 44. Four semi-circular notches 60, 60... are formed at the four corners of the front flange 59.

[0071] like Figure 3 and Figure 11 As shown, the rear housing 42 has a rear through hole 65 approximately in the center. The output shaft 10 passes through the rear through hole 65. A bearing 66 supporting the output shaft 10 is held at the rear of the rear through hole 65. An oil seal 67 is provided on the front side of the bearing 66.

[0072] A rear flange 68, which is quadrilateral in frontal view and is the same as the front flange 59 of the main body 44, is formed at the front end of the rear housing 42. Four semi-circular notches 69, 69... are also formed at the four corners of the rear flange 68.

[0073] The front flange 59 and the rear flange 68 are clamped together in a front-to-back overlapping state between the rear cylindrical portion 22 of the outer casing 3 and the connecting portion 6 of the motor housing 4. For example... Figure 5 and Figure 7 , Figure 9 As shown, at the rear end of the rear cylinder portion 22, four threaded fastening portions 70, 70... extending out to the four corners when viewed from the front. On the rear surface of each threaded fastening portion 70, a circular threaded boss 71 protruding rearward is formed.

[0074] On the other hand, at the four corners of the connecting part 6, such as Figure 5 and Figure 8 As shown, four internal threaded portions 72, 72... with internal threaded holes are formed corresponding to each threaded fastening portion 70. A circular recess 73 for engaging with a threaded boss 71 is formed on the front surface of each internal threaded portion 72. That is, as... Figure 12 As shown, each threaded boss 71 is nested with the circular recess 73 in a threaded fastening state based on the screw 8.

[0075] The front flange 59 and rear flange 68 are clamped between the threaded fastening part 70 and the internal thread part 72, with the notches 60 and 69 at the four corners engaging from the inside with the outer periphery of the threaded boss 71. In this state, each threaded fastening part 70 and internal thread part 72 is fastened from the front by screws 8, 8... Thus, the outer casing 3 and the motor casing 4 are connected together, and the front flange 59 and rear flange 68 are assembled together by pressing them together from both the front and rear sides. At this time, the rear end face of each threaded fastening part 70 does not contact the front end face of each internal thread part 72. In this way, the inner casing 40 is positioned at the rear of the outer casing 3.

[0076] In this positioning state, between the rear cylinder portion 22 and the front and rear flanges 59 and 68, such as Figure 3 and Figure 11 As shown, a gap S is formed on the upper side. Therefore, the connecting part 6 housing the fan 18 communicates with the gap S behind the O-ring 49. The gap S communicates with the space between the rear cylinder 22 and the front housing 41, and is connected to the front exhaust port 58 through the heat dissipation fins 57.

[0077] At the contact point between the front surface of the rear flange 68 and the front flange 59, such as Figure 6 As shown, a groove 74 is formed covering the entire circumference. An O-ring 75 is held within the groove 74. The O-ring 75 abuts against the rear surface of the front flange 59 to seal between the front flange 59 and the rear flange 68 when the inner housing 40 is assembled.

[0078] (Explanation of the rotation / impact switching unit)

[0079] For example Figure 6 , Figure 7 and Figure 11 , Figure 13 As shown, the rotation / impact switching unit 32 has two intermediate shafts, a first intermediate shaft 80 and a second intermediate shaft 81, on the lower side of the tool holder 23. The first intermediate shafts 80 and the second intermediate shaft 81 are arranged parallel to each other and parallel to the tool holder 23.

[0080] For example Figure 14 As shown, the rear end of the first intermediate shaft 80 on the left is rotatably supported on the rear housing 42 by a bearing 82. The front end of the first intermediate shaft 80 extends forward through the lower through hole 47 of the front housing 41. The front end of the first intermediate shaft 80 is rotatably supported on the front inner surface of the rear cylinder portion 22 by a bearing 83. At the rear of the first intermediate shaft 80, a first gear 84 that meshes with the pinion 17 of the output shaft 10 is rotatably mounted externally. A shim 84a is externally mounted between the bearing 82 and the first gear 84. A gear-side engagement portion 85 composed of multiple claws is formed on the front outer periphery of the first gear 84.

[0081] A second gear 86 is formed at the front of the first intermediate shaft 80, located slightly forward of the lower through hole 47. The second gear 86 meshes with the gear 38 of the tool holder 23. A shim 86a is externally fitted between the second gear 86 and the bearing 83.

[0082] A first spline portion 87 is formed on the first intermediate shaft 80 in front of the first gear 84. A first clutch 88 splines into the first spline portion 87. The first clutch 88 is configured to rotate integrally with the first intermediate shaft 80 and to move back and forth, and has a rear engaging portion 89 and a front engaging portion 90 composed of multiple pawls. Figure 13 In the retracted position shown, the rear engagement portion 89 of the first clutch 88 engages with the gear-side engagement portion 85 of the first gear 84. Therefore, the rotation of the first gear 84 is transmitted to the first intermediate shaft 80 through the first clutch 88.

[0083] A locking ring 91 is held in the lower through-hole 47 of the front housing 41 in front of the first clutch 88. Four anti-rotation plates 92, 92... are arranged at equal intervals along the circumference of the locking ring 91. The rear end of each anti-rotation plate 92 is a claw 92a protruding rearward from the rear end face of the locking ring 91. Four grooves 47a, 47a... are formed on the inner surface of the lower through-hole 47 for engaging the four anti-rotation plates 92. Therefore, the locking ring 91 is held in a state where rotation is restricted within the lower through-hole 47. In this state, the cylindrical inner circumferential surface 47b of the lower through-hole 47, except for each groove 47a, equally holds the outer circumferential surface of the locking ring 91 around the axis of the first intermediate shaft 80.

[0084] A coil spring 93 is housed in front of the locking ring 91 within the lower through hole 47. The locking ring 91 is pushed rearward by the coil spring 93. A stop ring 94 is held behind the locking ring 91 for the pawl 92a to abut. Therefore, the locking ring 91 is pushed toward a retracted position abutting against the stop ring 94.

[0085] The front engagement portion 90 of the first clutch 88 has eight more pawls 90a, 90a... than the four pawls 92a of the locking ring 91. When the first clutch 88 is in the forward position, it disengages from the first gear 84, and the pawls 90a of the front engagement portion 90 engage with the pawls 92a of the locking ring 91 in the rotational direction. Therefore, the rotation of the first gear 84 is not transmitted to the first intermediate shaft 80, and the rotation of the first intermediate shaft 80 is locked together with the first clutch 88.

[0086] When the rotation of the first intermediate shaft 80 is locked in this way, the rotation of the tool holder 23 is locked by the gear 38 that meshes with the second gear 86 of the first intermediate shaft 80.

[0087] However, in the intermediate position between the forward and reverse positions, the first clutch 88 is not engaged with either the first gear 84 or the locking ring 91.

[0088] A through hole 80a is formed on the first intermediate shaft 80 in the first spline portion 87 behind the locking ring 91. The through hole 80a has a circular cross-section and extends through the diameter of the first spline portion 87. A central hole 80b is formed at the center of the first intermediate shaft 80. The diameter of the central hole 80b is smaller than that of the through hole 80a, and it has a circular cross-section, with its front end connected to the through hole 80a. The rear end of the central hole 80b opens on the rear end face of the first intermediate shaft 80.

[0089] A retaining recess 42a for retaining the bearing 82 is formed on the front surface of the rear housing 42. A release hole 76 is formed through the rear housing 42 behind the retaining recess 42a. The release hole 76 is tapered, gradually tapering towards the rear. The release hole 76 communicates with the rear end of the shaft hole 80b through the bottom of the retaining recess 42a.

[0090] The bearing 82 is a bearing with seals on both its front and rear surfaces in the axial direction. Around the retaining recess 42a, an annular peripheral wall portion 42b is formed that protrudes forward beyond the bearing 82. The front end of the peripheral wall portion 42b is close to the rear surface of the first gear 84.

[0091] In this way, an air release path 77 is formed inside the inner housing 40. This air release path 77 extends from the inlets at both ends of the through hole 80a, through the axial hole 80b and the bottom of the retaining recess 42a, to the outlet at the rear end of the release hole 76. Therefore, the interior of the inner housing 40 communicates with the exterior of the inner housing 40 through the air release path 77. On the rear surface of the rear housing 42, an absorbent element 78, such as a sponge, is retained to close the rear end of the release hole 76.

[0092] The rear end of the second intermediate shaft 81 on the right side is rotatably supported on the rear housing 42 via a bearing 95. The front end of the second intermediate shaft 81 is rotatably supported on the bearing retainer 43 of the front housing 41 via a bearing 96. At the rear of the second intermediate shaft 81, a third gear 97 that meshes with the pinion 17 of the output shaft 10 is integrally fixed. In front of the third gear 97, a boss sleeve 98 is externally mounted on the second intermediate shaft 81 in a rotatable manner. A slant bearing 99 that tilts the axis is provided on the boss sleeve 98. An arm 100 is provided protruding upward on the outer ring of the slant bearing 99. The top end of the arm 100 is connected to the rear end of the piston cylinder 33. A helical spring 101 is located between the rear end of the piston cylinder 33 and the rear housing 42. In the drilling mode described later, the helical spring 101 applies force to the piston cylinder 33 to the forward position. A boss-side engaging portion 102 is formed at the front of the boss sleeve 98.

[0093] A second spline portion 103 is formed on the second intermediate shaft 81 in front of the boss sleeve 98. A second clutch 104 is splined into the second spline portion 103. The second clutch 104 is configured to rotate integrally with the second intermediate shaft 81 and move back and forth, and has a clutch-side engagement portion 105 at its rear. In the retracted position, the clutch-side engagement portion 105 of the second clutch 104 engages with the boss-side engagement portion 102 of the boss sleeve 98. Therefore, the rotation of the second intermediate shaft 81 is transmitted to the boss sleeve 98 via the second clutch 104. When the second clutch 104 moves forward, the clutch-side engagement portion 105 disengages from the boss-side engagement portion 102, and the rotation of the second intermediate shaft 81 is no longer transmitted to the boss sleeve 98.

[0094] A mode switching mechanism 109 is provided below the first intermediate shaft 80 and the second intermediate shaft 81. Also, Figure 15 As shown, the mode switching mechanism 109 has two first lever components 110 and a second lever component 111 on the left and right sides, and a switching knob 116.

[0095] The first rod component 110 and the second rod component 111 are parallel to each other and are arranged parallel to the first intermediate shaft 80 and the second intermediate shaft 81.

[0096] The rear end of the first lever member 110 is supported on the rear housing 42, and the front end is supported on the bearing retainer 43 of the front housing 41. The first lever member 110 has a first plate member 112. The first plate member 112 is a strip-shaped plate that extends parallel to the first lever member 110 in the middle. The front and rear ends of the first plate member 112 are bent toward the first lever member 110 and are penetrated by the first lever member 110. Therefore, the first plate member 112 can move back and forth along the first lever member 110. The front end of the first plate member 112 engages with the outer periphery of the first clutch 88. A coil spring 113 is installed in front of the first plate member 112 and outside the first lever member 110. The coil spring 113 applies force to the first plate member 112 toward a retracted position that abuts against the front surface of the rear housing 42. This retracted position is the retracted position of the first clutch 88 that retracts together with the first plate member 112.

[0097] The rear end of the second lever component 111 is supported on the rear housing 42, and the front end is supported on the bearing retainer 43 of the front housing 41. The second lever component 111 has a second plate component 114. The second plate component 114 is a strip-shaped plate extending parallel to the second lever component 111 in the middle. The front and rear ends of the second plate component 114 are bent toward the second lever component 111 and are penetrated by the second lever component 111. Therefore, the second plate component 114 can move back and forth along the second lever component 111. The front end of the second plate component 114 engages with the outer periphery of the second clutch 104. A coil spring 115 is installed in front of the second plate component 114 and outside the second lever component 111. The coil spring 115 applies force to the second plate component 114 toward a retracted position that abuts against the rear housing 42. This retracted position is the retracted position of the second clutch 104 that retracts together with the second plate component 114.

[0098] The positions of the first plate component 112 and the second plate component 114 can be changed by the switching knob 116. For example... Figure 16 As shown, the switching knob 116 is located on the lower surface of the rear cylinder 22 in a rotatable manner. Figure 3 , Figure 11 As shown, the switching knob 116 protrudes into the inner housing 40 through a bottom through-hole 117 on the lower surface of the main body 44 of the front housing 41. Two eccentric pins, a first eccentric pin 118 and a second eccentric pin 119, are provided on the protruding end face of the switching knob 116. The first eccentric pin 118 engages with the front end of the first plate member 112 from the rear, and the second eccentric pin 119 engages with the middle part of the second plate member 114 from the rear.

[0099] Therefore, by rotating the operating switch knob 116, the front and rear positions of the first plate component 112 and the second plate component 114 can be switched via the first eccentric pin 118 and the second eccentric pin 119. That is, the working mode can be switched between drilling mode, hammer drilling mode, hammering mode (rotary locking), and hammering mode (idling).

[0100] (Explanation of the hammer drill's motion)

[0101] Switch knob 116 to drilling mode. The first eccentric pin 118 then reaches its final retracted position, and the first clutch 88, together with the first plate component 112, reaches the retracted position. Thus, rotation of the first gear 84 is transmitted to the first intermediate shaft 80 via the first clutch 88. Furthermore, rotation of the first intermediate shaft 80 is transmitted from the second gear 86 to the tool holder 23 via gear 38.

[0102] On the other hand, the second eccentric pin 119 reaches its forward position, and the second clutch 104 and the second plate component 114 reach the forward position together. Therefore, the rotation of the second intermediate shaft 81 transmitted from the output shaft 10 is no longer transmitted to the boss sleeve 98.

[0103] Therefore, when the trigger 14 is pressed to turn on the switch 13, the motor 9 is driven to rotate the output shaft 10. This, in turn, rotates the tool holder 23 via the first intermediate shaft 80, thereby rotating the tool head B at the tip.

[0104] Next, switch knob 116 to hammer drill mode. As a result, the final retracted position of the first eccentric pin 118 remains unchanged, and the first plate component 112 and the first clutch 88 remain in the retracted position.

[0105] On the other hand, the second eccentric pin 119 retracts from the forward position to the intermediate position, and the second clutch 104, together with the second plate component 114, reaches the retracted position. Therefore, the rotation of the second intermediate shaft 81 is transmitted to the boss sleeve 98 through the second clutch 104.

[0106] Therefore, when the trigger 14 is pressed to drive the motor 9, the tool holder 23 rotates via the first intermediate shaft 80, thereby rotating the tool head B at the top. Simultaneously, the boss sleeve 98 rotates, causing the arm 100 to swing back and forth, thus reciprocating the piston cylinder 33. Consequently, the hammer 34 reciprocates, impacting the tool head B via the striker 35.

[0107] Next, switch knob 116 to hammer mode (rotation lock). The first eccentric pin 118 then reaches its forward position. The first clutch 88, together with the first plate component 112, reaches the forward position and engages with the locking ring 91. Therefore, rotation of the first gear 84 is no longer transmitted to the first intermediate shaft 80, and together with the first intermediate shaft 80, rotation of the tool holder 23 is locked.

[0108] On the other hand, the second eccentric pin 119 reaches the final retracted position, and the second clutch 104 remains in the retracted position. Therefore, the rotation of the second intermediate shaft 81 is transmitted to the boss sleeve 98 via the second clutch 104.

[0109] Therefore, when the trigger 14 is pressed to drive the motor 9, the piston cylinder 33 reciprocates while the rotation of the tool holder 23 is locked, and the hammer 34 impacts the tool head B through the striker 35.

[0110] Additionally, sometimes when the first clutch 88 is advancing, the front surface of the pawl 90a of the front engaging portion 90 abuts against the rear surface of the pawl 92a of the locking ring 91, but they do not engage in the rotational direction. However, in this case, the locking ring 91 advances against the force of the coil spring 93, allowing the first clutch 88 to advance.

[0111] Therefore, when the first intermediate shaft 80 rotates due to friction with the first gear 84, thereby causing the first clutch 88 to rotate, during the phase when the pawl 92a and pawl 90a are engaged, the locking ring 91 retracts and engages with the first clutch 88. Thus, the rotation of the first intermediate shaft 80 is locked.

[0112] Next, switch knob 116 to hammer mode (idle). The first eccentric pin 118 then retracts from its forward position to the intermediate position. The first clutch 88 retracts together with the first plate component 112, disengaging from the locking ring 91. However, the first clutch 88 reaches the intermediate position where it is not engaged with the first gear 84. Therefore, rotation of the first gear 84 is not transmitted to the first intermediate shaft 80, and the tool holder 23 rotates freely together with the first intermediate shaft 80.

[0113] On the other hand, the second eccentric pin 119 advances from the final retracted position to the intermediate position, and the second clutch 104, together with the second plate component 114, reaches the retracted position. Therefore, the rotation of the second intermediate shaft 81 is transmitted to the boss sleeve 98 through the second clutch 104.

[0114] Therefore, when the trigger 14 is pressed to drive the motor 9, the tool holder 23 becomes free to rotate, the piston cylinder 33 reciprocates, and the hammer 34 impacts the tool head B through the striker 35.

[0115] In this way, when the hammer drill 1 operates in various working modes, the rotation of the output shaft 10 causes the fan 18 to rotate. External air is then drawn into the motor housing 7 of the motor housing 4 through the rear air inlet 16, and this external air moves forward to cool the motor 9. This cooling air flows within the connecting portion 6, with a portion being discharged to the outside from the rear exhaust port 20. Another portion moves forward within the connecting portion 6 and flows into the rear cylinder 22 through the gap S between the rear cylinder 22 and the front and rear flanges 59, 68. Then, the cooling air is discharged from the front exhaust port 58 through the outer space of the inner housing 40. At this time, the cooling air contacts the front housing 41, suppressing the temperature rise of the front housing 41 due to heat generated in the drive mechanism 30. In particular, since the cooling air flows along the heat dissipation fins 57, the heat of the front housing 41 can be effectively dissipated.

[0116] On the other hand, lubricating oil is filled in the receiving area T. In particular, the front lubricating oil chamber 55 in the front cylinder 21 becomes a narrow space that saves useless space through the partition wall 54, so the filling rate of lubricating oil in the front lubricating oil chamber 55 is high. Therefore, the lubricating oil that has splashed out from the rotating / impact action part 31 can easily re-adhere to the gear 38, etc.

[0117] Furthermore, sometimes the pressure within the housing area T increases due to the expansion of air caused by the heat generated by the drive mechanism 30. Consequently, air in the rear lubricating oil chamber 56 enters the air release path 77 from both ends of the through hole 80a of the first intermediate shaft 80. Then, the air is discharged to the outside of the inner housing 40 through the through hole 80a, the shaft hole 80b, the bottom of the retaining recess 42a, and the release hole 76. Therefore, the pressure within the rear lubricating oil chamber 56 is released.

[0118] At this time, the through hole 80a, which serves as the inlet to the air release path 77, is located on the circumferential surface of the first intermediate shaft 80. Therefore, due to the centrifugal force generated when the first intermediate shaft 80 rotates, the lubricating oil in the rear lubricating oil cavity 56 is difficult to enter through the through hole 80a. In particular, the through hole 80a is formed on the first spline portion 87, so the lubricating oil is agitated by the rotating spline teeth, which appropriately prevents the lubricating oil from entering the through hole 80a.

[0119] Furthermore, a peripheral wall portion 42b is formed at the opening of the retaining recess 42a, thus preventing lubricating oil from flowing onto the front surface of the rear housing 42 and entering the retaining recess 42a. In particular, since the peripheral wall portion 42b is adjacent to the first gear 84, the rotation of the first gear 84 agitates the lubricating oil, which also appropriately prevents lubricating oil from entering the gap between the first gear 84 and the peripheral wall portion 42b. Even if the lubricating oil passes over the peripheral wall portion 42b, the bearing 82 with a seal prevents it from flowing into the bottom of the retaining recess 42a.

[0120] (Effects of inventions related to air release paths)

[0121] The hammer drill 1 (an example of an impact tool) described above includes, within the housing 2: a motor 9; a tool holder 23, which is cylindrical and has a tool head B mounted at its top; and a drive mechanism 30 capable of impacting the tool head B. Furthermore, the hammer drill 1 includes: a first intermediate shaft 80 (an example of a rotating shaft), which is mounted on the drive mechanism 30 and rotates via the rotation of the output shaft 10 of the motor 9; and a receiving area T, which houses the drive mechanism 30 in a sealed state within the housing 2. Additionally, the hammer drill 1 has an air release path 77 formed inside the first intermediate shaft 80, releasing air from the receiving area T to the outside of the receiving area T, and a through hole 80a, serving as the inlet of the air release path 77, is formed on the outer peripheral surface of the first intermediate shaft 80.

[0122] According to this structure, the lubricating oil in the rear lubrication chamber 56 is less likely to enter through the air release path 77 due to the centrifugal force of the first intermediate shaft 80. Therefore, the pressure rising in the housing area T due to the heat generated by the drive mechanism 30 can be effectively released.

[0123] The inlet of the air release path 77 is formed by a through hole 80a that is orthogonally inserted through the first intermediate shaft 80. Therefore, air can enter from both ends of the through hole 80a, and even if one end is blocked by lubricating oil, air can still enter from the other end.

[0124] Within the containment area T, a bearing 82 supporting the first intermediate shaft 80 is provided, and the outlet of the air release path 77 is disposed on the opposite side of the containment area T, separated from the bearing 82 in the axial direction of the first intermediate shaft 80. Therefore, the air release path 77 can be formed over a relatively short distance in the axial direction of the first intermediate shaft 80.

[0125] Bearing 82 is a sealed bearing. Therefore, the possibility of lubricating oil flowing from bearing 82 into air release path 77 can be reduced.

[0126] The through hole 80a is located at the middle position in the axial direction of the first intermediate shaft 80. Therefore, the lubricating oil in the rear lubrication oil cavity 56 is less likely to enter through the through hole 80a.

[0127] A first spline portion 87 (an example of a spline portion) is formed on the first intermediate shaft 80. A first clutch 88 (an example of a clutch) for switching operating modes is slidably engaged with the first spline portion 87, and a through hole 80a is disposed on the first spline portion 87. Therefore, by agitating the lubricating oil by the rotating spline teeth, lubricating oil is appropriately prevented from entering the through hole 80a.

[0128] An inner housing 40 forms a receiving area T, which is disposed within the housing 2 and has a retaining recess 42a for retaining the bearing 82. An annular peripheral wall portion 42b protruding toward the receiving area T is formed around the retaining recess 42a. Therefore, lubricating oil does not easily flow on the inner surface of the inner housing 40 and enter the retaining recess 42a.

[0129] A first gear 84 (gear example) is provided on the first intermediate shaft 80, which is adjacent to the peripheral wall portion 42b in the axial direction. Therefore, by rotating the first gear 84 to agitate the lubricating oil, it is also possible to appropriately prevent the lubricating oil from entering the gap between the first gear 84 and the peripheral wall portion 42b.

[0130] The drive mechanism 30 has a rotation / impact actuation unit 31 (an example of a rotation actuation unit) for rotating the tool holder 23. The drive mechanism 30 also has a first intermediate shaft 80 (an example of a rotation shaft) for transmitting rotation to the tool holder 23 and a second intermediate shaft 81 (an example of a rotation shaft) for impacting the tool head B. The rotation shaft with a through hole 80a is the first intermediate shaft 80 for transmitting rotation. Therefore, an air release path 77 can be easily formed.

[0131] In addition, the following changes can be made in inventions related to air release paths.

[0132] The inlet location of the air release path is not limited to the middle part of the intermediate shaft as described above. The inlet can also be located at the front or rear end, as long as it is on the outer circumference of the rotating shaft. The inlet may also not be located at the spline section.

[0133] The entrance does not necessarily have to be a through hole. For example, the entrance can be formed by a bottomed hole with one end open on the circumferential surface of the rotating shaft and the other end located inside the rotating shaft. The through hole and the bottomed hole can also be formed not along the radial direction of the rotating shaft, but in an inclined manner towards the axial direction of the rotating shaft.

[0134] The size and shape of the cross-sectional area of ​​the air release path are not limited to the methods described above. In the methods described above, the diameter of the axial hole can be the same as that of the through hole, or the diameter of the axial hole can be larger than that of the through hole. The cross-section of the air release path also does not have to be circular.

[0135] The air release path can also be set on the intermediate shaft used for impact. If there is only one intermediate shaft, the air release path can also be set on that intermediate shaft. The air release path is not limited to the intermediate shaft used for rotation / impact switching, and can also be set on other rotating shafts.

[0136] This invention is not limited to hammer drills. It can also be applied to other impact tools such as electric hammers.

[0137] Impact tools are not limited to structures that reciprocate a piston cylinder via an intermediate shaft (which can also be a single shaft) and a rotary conversion component. For example, impact tools can also employ a crankshaft mechanism and a connecting rod assembly to reciprocate a piston cylinder.

[0138] (Effects of the invention related to the locking ring of the tool holder)

[0139] The hammer drill 1 described above includes a motor 9, a tool holder 23, and a drive mechanism 30 within a housing 2. The tool holder 23 is cylindrical, with a tool head B mounted at its top, and is rotatable. The drive mechanism 30 performs the rotation of the tool holder 23 and / or the impact of the tool head B. Furthermore, the hammer drill 1 has a mode switching mechanism 109, which can switch the operating mode of the drive mechanism 30 between at least a hammering mode and a hammer drilling mode. The hammering mode refers to a mode in which only the tool head B performs an impact; the hammer drilling mode refers to a mode in which both the tool holder 23 rotates and the tool head B impacts. Additionally, the drive mechanism 30 has a first intermediate shaft 80 (an example of a rotation transmission shaft) for transmitting the rotation of the output shaft 10 of the motor 9 to the tool holder 23. A first clutch 88 (an example of a rotation transmission component) is provided on the first intermediate shaft 80 for transmitting rotation to the tool holder 23. Furthermore, a locking ring 91 (an example of a locking component) is disposed on the axis of the first intermediate shaft 80. The locking ring 91 is used to engage with the first clutch 88 to limit the rotation of the tool holder 23. The locking ring 91 passes through the front housing 41 within the housing 2 and is held equally around the axis of the first intermediate shaft 80 by the lower through hole 47.

[0140] According to this structure, since the locking ring 91 is positioned on the axis of the first intermediate shaft 80, space is saved, and the housing 2 is made more compact. Furthermore, even when a force in the rotational direction is applied from the tool holder 23 side when rotation is restricted, twisting and tilting of the locking ring 91 are suppressed. Therefore, it is possible to restrict the rotation of the tool holder 23 in a space-saving and low-cost manner.

[0141] The locking ring 91 is annular. Therefore, it can be installed around the first intermediate shaft 80 in a space-saving manner. In addition, it is less prone to twisting or tilting.

[0142] The rotational transmission component is a first clutch 88 (an example of a clutch), which is provided on the first intermediate shaft 80 for switching the rotational transmission to the tool holder 23. Therefore, rotational restriction of the tool holder 23 can be easily achieved using the first clutch 88.

[0143] The first clutch 88 slides on the axis of the first intermediate shaft 80 during the switching operation of the mode switching mechanism 109, engaging and disengaging with the locking ring 91. Therefore, the first clutch 88 can engage and disengage with the locking ring 91 in a facing state, and the locking ring 91 is less likely to twist or tilt when switching rotation limits.

[0144] The locking ring 91 is configured to move along the axial direction of the first intermediate shaft 80, and is forced by the coil spring 93 (an example of an elastic member) to a position where the first clutch 88 can engage. Therefore, even if it cannot engage with the first clutch 88 and the first clutch 88 collides with it, the locking ring 91 can move along the axial direction to avoid impact, and when it becomes capable of engaging with the first clutch 88, it can return to its original position and reliably engage. In particular, since the coil spring 93 and the locking ring 91 are arranged on the same axis, the movement of the locking ring 91 is smooth.

[0145] The locking ring 91 has an anti-rotation piece 92 (an example of an anti-rotation part) that engages with the groove 47a of the lower through hole 47 of the front housing 41. The anti-rotation piece 92 also serves as an engaging part that engages with the first clutch 88. Therefore, it is a reasonable structure that does not complicate the shape of the locking ring 91.

[0146] The lower through-hole 47 of the front housing 41 (an example of the holding portion of the locking ring 91) has an inner circumferential surface 47b (an example of a circumferential surface), which slides in contact with the outer surface of the locking ring 91 about the axis of the first intermediate shaft 80. Therefore, the locking ring 91 is held evenly, increasing durability. In addition, it smoothly guides the locking ring 91 to move along the axial direction.

[0147] The engaged portion of the locking ring 91 that engages with the first clutch 88 and the front engaged portion 90 (an example of an engaged portion) of the first clutch 88 that engages with the locking ring 91 are formed by pawls 90a and pawls 92a of different numbers. Therefore, the first clutch 88 is easily engaged with the locking ring 91.

[0148] The drive mechanism 30 has two intermediate shafts, a first intermediate shaft 80 and a second intermediate shaft 81, parallel to the tool holder 23. The first intermediate shaft 80 is a rotation transmission shaft, and the second intermediate shaft 81 is used to perform an impact action on the tool head B. Therefore, the locking ring 91 can be easily positioned on the axis of the first intermediate shaft 80.

[0149] In addition, the following modifications can be made in inventions related to the locking ring of the tool holder.

[0150] The number of claws in the locking ring can be increased or decreased. The shape of the claws can also be changed. The claws may also not serve as the anti-rotation part of the locking ring.

[0151] The rotary transmission component that engages and disengages with the locking ring is not limited to a clutch. For example, the rotary transmission component may be a gear disposed on a rotating shaft and meshing with a tool holder, which engages and disengages with the locking ring by sliding the gear.

[0152] The locking ring may also not be configured to slide along the axial direction.

[0153] The locking component is not limited to the ring-shaped locking component described above. Its shape can be changed, for example, it can be a cross shape formed by two plates intersecting.

[0154] The operating modes selectable in a hammer drill are not limited to four. As long as at least the hammering mode and the hammer drilling mode can be selected, this invention can be applied. The structure of the mode switching mechanism and the switching knob can also be appropriately modified.

[0155] The following describes common modifications to the inventions.

[0156] The direction of the motor is not limited to the front and back direction, and can be changed appropriately.

[0157] The motor is not limited to a brushed motor; a brushless motor can also be used.

[0158] The power source doesn't have to be a commercial power source; it can be a battery pack.

[0159] Impact action can also be a structure where a piston reciprocates within a fixed cylinder, rather than a piston-cylinder system. Alternatively, it can be a structure where a hammer directly impacts the tool head, without a striking bolt.

[0160] Furthermore, based on the above method, the following other inventions can also be extracted.

[0161] (Other Invention 1)

[0162] A hammer drill, comprising a motor, a tool holder, a drive mechanism, and a mode switching mechanism within a housing, wherein...

[0163] The tool holder is cylindrical, with a tool head mounted at its top and capable of rotation;

[0164] The drive mechanism is capable of performing the rotational action of the tool holder and / or the impact action of the tool head;

[0165] The mode switching mechanism can switch the operating mode of the drive mechanism between at least a hammering mode and a hammer-drilling mode. The hammering mode refers to a mode in which only the tool head performs an impact action; the hammer-drilling mode refers to a mode in which the tool holder rotates and the tool head performs an impact action.

[0166] The drive mechanism has a rotary transmission shaft for transmitting the rotation of the motor's output shaft to the tool holder. A rotary transmission component is provided on the rotary transmission shaft for transmitting rotation to the tool holder.

[0167] The characteristic of this hammer drill is that...

[0168] A locking member is disposed on the axis of the rotary transmission shaft. The locking member is used to engage with the rotary transmission member to limit the rotation of the tool holder. The locking member is held equally within the housing about the axis of the rotary transmission shaft.

[0169] (Other Inventions 2)

[0170] According to another invention 1, the hammer drill is characterized in that the locking component is ring-shaped.

[0171] (Other Inventions 3)

[0172] The hammer drill according to other inventions 1 or 2 is characterized in that the rotational transmission component is a clutch, which is disposed on the rotational transmission shaft for switching the rotational transmission to the tool holder.

[0173] (Other Inventions 4)

[0174] According to the hammer drill of other invention 3, the clutch slides on the axis of the rotary transmission shaft and engages and disengages with the locking component as the mode switching mechanism switches.

[0175] (5 other inventions)

[0176] The hammer drill according to any one of the other inventions 1 to 4 is characterized in that the locking member is configured to move along the axial direction of the rotary transmission shaft and is subjected to force by the elastic member at a position where the rotary transmission member can engage.

[0177] (6 other inventions)

[0178] The hammer drill according to any one of the other inventions 1 to 5 is characterized in that the locking member has an anti-rotation part that engages within the housing, the anti-rotation part also serving as an engaged part that engages with the rotation transmission member.

[0179] (Other Inventions 7)

[0180] The hammer drill according to any one of the other inventions 1 to 6 is characterized in that the retaining portion of the locking member in the housing has a circumferential surface that slides in contact with the outer surface of the locking member about the axis of the rotation transmission shaft.

[0181] (8 other inventions)

[0182] The hammer drill according to any one of the other inventions 1 to 7 is characterized in that the engaged portion of the locking member that engages with the rotary transmission member and the engaged portion of the rotary transmission member that engages with the locking member are formed by claws of different numbers.

[0183] (9 other inventions)

[0184] The hammer drill according to any one of the other inventions 1 to 8 is characterized in that the drive mechanism has two rotating shafts parallel to the tool holder, one of the rotating shafts being the rotation transmission shaft, and the other rotating shaft being used to perform an impact action on the tool head.

Claims

1. An impact tool, characterized in that, The housing contains a motor, a tool holder, a drive mechanism, a rotating shaft, and a drive mechanism housing area. The tool holder is cylindrical, and a tool head can be mounted on its top. The drive mechanism can impact the tool head; The rotating shaft is disposed on the drive mechanism and rotates by the rotation of the output shaft of the motor; The drive mechanism receiving area houses the drive mechanism in a sealed state within the housing. An air release path is formed inside the rotating shaft to release air from the drive mechanism housing area to the outside of the drive mechanism housing area, and the inlet of the air release path is formed on the outer peripheral surface of the rotating shaft. The entrance is formed by an orthogonal through-hole that passes through the rotating shaft and is directly connected to the drive mechanism receiving area.

2. An impact tool, characterized in that, The housing contains a motor, a tool holder, a drive mechanism, a rotating shaft, and a drive mechanism housing area. The tool holder is cylindrical, and a tool head can be mounted on its top. The drive mechanism can impact the tool head; The rotating shaft is disposed on the drive mechanism and rotates by the rotation of the output shaft of the motor; The drive mechanism receiving area houses the drive mechanism in a sealed state within the housing. An air release path is formed inside the rotating shaft to release air from the drive mechanism housing area to the outside of the drive mechanism housing area, and the inlet of the air release path is formed on the outer peripheral surface of the rotating shaft. A spline portion is formed on the rotating shaft, and a clutch for switching working modes is slidably engaged with the spline portion, with the inlet disposed on the spline portion.

3. The impact tool according to claim 1, characterized in that, The cross-section of the through hole is circular.

4. The impact tool according to claim 1 or 2, characterized in that, A bearing supporting the rotating shaft is provided within the drive mechanism housing area, and the outlet of the air release path is formed on the opposite side of the drive mechanism housing area, across the bearing, in the axial direction of the rotating shaft.

5. The impact tool according to claim 4, characterized in that, The outlet is sealed by a breathable lubricating oil absorber.

6. The impact tool according to claim 4, characterized in that, The bearing is a bearing with a seal.

7. The impact tool according to claim 5, characterized in that, The bearing is a bearing with a seal.

8. The impact tool according to claim 1 or 2, characterized in that, The inlet is located at the middle position in the axial direction of the rotating shaft.

9. The impact tool according to claim 4, characterized in that, The drive mechanism receiving area is formed by an inner housing, which is disposed within the housing and has a retaining recess for holding the bearing. Around the retaining recess, an annular peripheral wall portion protruding toward the drive mechanism receiving area is formed.

10. The impact tool according to claim 5 or 6, characterized in that, The drive mechanism receiving area is formed by an inner housing, which is disposed within the housing and has a retaining recess for holding the bearing. Around the retaining recess, an annular peripheral wall portion protruding toward the drive mechanism receiving area is formed.

11. The impact tool according to claim 9, characterized in that, The air release path includes a central hole and a release hole, wherein the central hole is formed at the axis of the rotating shaft and communicates with the retaining recess; the release hole is formed in the inner housing and communicates with the retaining recess, and has the outlet.

12. The impact tool according to claim 11, characterized in that, The release hole is formed as a cone that gradually tapers towards the outlet.

13. The impact tool according to claim 11, characterized in that, The diameter of the central bore is smaller than that of the inlet.

14. The impact tool according to claim 9, characterized in that, A gear is provided on the rotating shaft that is adjacent to the peripheral wall portion in the axial direction.

15. The impact tool according to claim 1 or 2, characterized in that, The drive mechanism has a rotating action part for rotating the tool holder, and a rotating shaft for transmitting rotation to the tool holder and a rotating shaft for impacting the tool head, wherein the rotating shaft having the inlet is the rotating shaft for transmitting rotation.

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