hammer drill

Abstract

This invention provides a hammer drill. The hammer drill (1) has within a housing (2) a motor (9); a tool holder (23); a drive mechanism (30); a flange sleeve (98) that converts the rotation of the output shaft (10) into the impact action of the drill bit (B); and an inner housing (40) that supports the drive mechanism and supports the tool holder (23) by bearing bushes (46) and the output shaft (10) by bearings (66). The inner housing is divided into a front housing (41) and a rear housing (42), which are connected in the axial direction of the tool holder. The front housing is used to hold the bearing bushes, and the rear housing is separately formed from the front housing and is used to hold the bearings. An O-ring (49) is provided on the front housing to seal the outer space of the inner housing within the housing. Accordingly, even when the inner housing is divided to form a drive mechanism housing area, compactness can be achieved, and a suitable cooling effect for the drive mechanism can be obtained.

Description

Technical Field

[0001] This invention relates to a hammer drill. Background Technology

[0002] The hammer drill houses a cylindrical tool holder, at the top of which a drill bit can be mounted, in a rotatable manner within its housing. The tool holder has a reciprocating piston (including a piston cylinder) and a hammer that reciprocates in conjunction with the piston under the action of an air spring. A drive mechanism is formed within the housing, comprising the tool holder, piston, and hammer, and capable of imparting rotational and / or impact motion to the drill bit.

[0003] Furthermore, as disclosed in Patent Document 1, an intermediate shaft parallel to the tool holder is provided on the drive mechanism. The intermediate shaft has a flange sleeve as a rotation conversion component, which transmits the rotation of the motor's output shaft to the tool holder and converts the rotation of the output shaft into the reciprocating motion of the piston. The flange sleeve includes an arm that swings back and forth via an externally mounted swash bearing at an inclined axis, connecting the arm to the piston, thereby causing the piston to reciprocate through the swinging of the arm.

[0004] Furthermore, an inner housing supporting the drive mechanism is provided within the housing. The inner housing has: a front plate portion that supports the rear portion of the tool holder via a bearing; a rear plate portion that supports the output shaft via a bearing; and a connecting portion for connecting the front plate portion and the rear plate portion.

[0005] [Existing technical documents]

[0006] [Patent Literature]

[0007] Patent Document 1: Japanese Patent Publication No. 2020-104238 Summary of the Invention

[0008] [The technical problem the invention aims to solve]

[0009] In the hammer drill of Patent Document 1, a sealing member is sandwiched between the outer periphery of the rear plate portion of the inner housing, which has a larger radial dimension, and the inner periphery of the rear portion of the housing. This sealing member separates and forms an area (drive mechanism housing area) for housing the drive mechanism on the front side of the rear plate portion and within the housing. Therefore, the size of both the drive mechanism housing area and the housing becomes larger.

[0010] Furthermore, in the hammer drill of Patent Document 1, a fan for cooling the motor is provided on the output shaft behind the rear plate. However, the air that has cooled the motor is discharged radially outward from the fan to the outside of the housing behind the rear plate. Therefore, the cooling effect on the drive mechanism is insufficient.

[0011] Therefore, the object of the present invention is to provide a hammer drill that can achieve compactness even when the inner housing is divided to form a drive mechanism housing area, and can also obtain a suitable cooling effect for the drive mechanism.

[0012] [Technical solutions used to solve technical problems]

[0013] To achieve the above objectives, the present invention is characterized by having a motor, a cylindrical tool holder, a drive mechanism, a rotary conversion component, and an inner housing within the housing, wherein...

[0014] The tool holder is used to mount the drill bit at the top and is rotatable;

[0015] The drive mechanism can perform the rotation of the tool holder and / or the impact of the drill bit;

[0016] The rotation conversion component is disposed in the drive mechanism and can convert the rotation of the motor's output shaft into the impact action of the drill bit;

[0017] The inner housing supports the drive mechanism, and the tool holder is supported by a first bearing, while the output shaft is supported by a second bearing.

[0018] The inner housing is divided into a front housing and a rear housing, and is formed by connecting the front housing and the rear housing in the axial direction of the tool holder. The front housing is used to hold the first bearing; the rear housing is separately formed from the front housing and is used to hold the second bearing.

[0019] A sealing component is provided on the front housing, which is used to seal the outer space of the inner housing within the housing.

[0020] [Invention Effects]

[0021] According to the present invention, since the inner housing is divided into front and rear parts and a sealing member is provided on the front housing, an inner housing with a reduced drive mechanism housing area can be formed on the rear side of the sealing member. This also contributes to the compactness of the product size. Furthermore, since the cooling air of the motor can be guided to the outside of the inner housing, a suitable cooling effect for the drive mechanism can be obtained. Attached Figure Description

[0022] Figure 1 This is a three-dimensional view of the hammer drill from the rear.

[0023] Figure 2 This is a central longitudinal section view of a hammer drill.

[0024] Figure 3 yes Figure 2 An enlarged view of the drive mechanism section.

[0025] Figure 4 yes Figure 3 AA sectional view.

[0026] Figure 5 It is an exploded three-dimensional view of the outer casing, motor housing, and inner casing.

[0027] Figure 6 This is an exploded three-dimensional view of the inner shell.

[0028] Figure 7 yes Figure 3 BB cross-sectional view.

[0029] Figure 8 This is an enlarged front view omitting the outer casing, inner casing, and motor casing.

[0030] Figure 9 This is an enlarged rear view of the outer casing.

[0031] Figure 10 yes Figure 8 FF sectional view (with outer shell).

[0032] Figure 11 yes Figure 3 CC section view.

[0033] Figure 12 yes Figure 7 DD sectional view.

[0034] Figure 13 yes Figure 7 EE sectional view.

[0035] Figure 14 yes Figure 11 GG cross-sectional view.

[0036] Figure 15 This is a partial bottom view of the outer shell.

[0037] [Explanation of reference numerals in the attached figures]

[0038] 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; 43: Bearing holder; 44: Main body; 45: Upper through hole; 46: Bearing shell (metal); 49: O-ring; 50: Inner rib; 52: Outer rib; 54: Partition wall; 55: Front grease chamber; 56: Rear grease chamber; 58: Front exhaust port; 59: Front flange; 60, 69: Notch; 68: Rear flange; 70: Threaded fastening part; 71: Threaded protrusion; 72: Internal thread part; 73: Circular recess; 80: First intermediate shaft; 81: Second intermediate shaft; 84: First gear; 86: Second gear; 88: First clutch; 97: Third gear; 98: Flange sleeve; 104: Second clutch; 109: Mode switching mechanism; 116: Switching knob; T: Drive mechanism receiving area; B: Drill bit. Detailed Implementation

[0039] In one embodiment of the invention, the rotary conversion component can be housed within the front housing. According to this structure, the heat generated by the movement of the rotary conversion component can be effectively cooled via the front housing.

[0040] In one embodiment of the invention, the sealing member can be positioned forward of the rotary conversion member. According to this structure, the outer space of the inner housing, through which cooling airflow can flow, is formed radially outward of the rotary conversion member.

[0041] In one embodiment of the invention, the sealing member can be located radially outward of the first bearing. According to this structure, the sealing member is positioned close to the foremost part of the inner housing, ensuring a larger outer space.

[0042] In one embodiment of the invention, an airflow path may be formed radially outward of the rotary conversion component in the outer space. According to this structure, heat transferred from the rotary conversion component can be effectively cooled from the outside of the inner housing.

[0043] In one embodiment of the invention, the front housing may be made of metal. This structure allows for effective heat dissipation from the inner housing.

[0044] In one embodiment of the invention, a connection surface sealing member may be provided on the connection surface between the front housing and the rear housing. According to this structure, sealing can be ensured even if the inner housing is divided into two parts.

[0045] In one embodiment of the invention, the drive mechanism may have two intermediate shafts parallel to the axial direction of the tool holder. One intermediate shaft transmits the rotation of the output shaft to the tool holder, while the other intermediate shaft converts the rotation of the output shaft into the impact action of the drill bit via a rotation conversion component. According to this structure, by having one intermediate shaft share the function of rotation transmission and the other intermediate shaft share the function of impact transmission, the two intermediate shafts can be shortened axially respectively. Therefore, this contributes to the overall compactness of the rotation / impact switching unit.

[0046] In one embodiment of the present invention, heat sinks may be formed on the outer surface of the front housing. This structure allows for effective heat dissipation from the front housing.

[0047] In one embodiment of the invention, the motor is configured such that its output shaft extends along the axial direction of the tool holder. A fan is mounted on the output shaft. An air inlet is located at either the front or rear of the housing, and an exhaust outlet is located at the other. The air inlet and exhaust outlet face each other across the axial direction of the output shaft. This structure provides balanced and effective cooling of the inner housing.

[0048] [Example]

[0049] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0050] (Brief explanation of hammer drill)

[0051] 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.

[0052] 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.

[0053] The motor housing 4 has a quadrilateral connecting portion 6 on the front side when viewed from the front, and a cylindrical motor housing portion 7 on the rear side. Also... Figure 5 As shown, the connecting part 6 is connected to the outer casing 3 from the front at its four corners by four screws 8, 8... when viewed from the front. The motor 9 is housed in the motor housing part 7 with its output shaft 10 facing forward.

[0054] The handle housing 5 is externally mounted to the motor housing 7 from the rear and can move relative to it in the forward and backward directions. The handle housing 5 is pushed to the rearward position by means of the anti-vibration mechanism of the coil spring 11.

[0055] 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.

[0056] The output shaft 10 of the motor 9 protrudes into the housing 3 through the connecting part 6. A pinion 17 is formed at the front end of the output shaft 10. A fan 18 is fixed inside the connecting part 6 and on the output shaft 10. A baffle 19 is fixed behind the fan 18 and inside the connecting part 6. Multiple exhaust ports 20, 20... are formed radially outward of the fan 18 and on the lower and right side surfaces of the connecting part 6, respectively.

[0057] 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 the rear cylindrical portion 22 is a hexagonal cylindrical shape when viewed from the front. The front cylindrical portion 21 is positioned off-center above the rear cylindrical portion 22.

[0058] 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. A bearing 24 is held at the front end of the front cylindrical portion 21, supporting the front portion of the tool holder 23. An oil seal 25 is provided in front of the bearing 24, sealing the space between the front cylindrical portion 21 and the tool holder 23.

[0059] An operating sleeve 26 is provided at the front end of the tool holder 23, which protrudes from the front barrel 21. The operating sleeve 26 is configured for attaching and detaching the drill bit B at the front end of the tool holder 23. A side handle 27 is installed at the front end of the front barrel 21.

[0060] 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.

[0061] 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 via an air chamber 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. A gear 38 with a torque limiter is provided in the rear cylinder portion 22 and on the outer periphery of the tool holder 23.

[0062] The connecting part 6 and the rear cylinder part 22 house an inner housing 40. The inner housing 40 supports the rear of the tool holder 23 on the rear side of the gear 38. The inner housing 40 houses a rotation / impact switching part 32. By operating the switching knob 116 provided on the lower surface of the rear cylinder part 22, the rotation / impact switching part 32 switches the operating mode and transmits the rotation of the output shaft 10 to the rotation / impact operating part 31.

[0063] (Description of the inner shell)

[0064] The inner housing 40 is divided into two parts, front and rear, having a metal front housing 41 and a resin rear housing 42.

[0065] 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.

[0066] The bearing retaining part 43 is hexagonal when viewed from the front, and is slightly smaller than the rear cylinder part 22. 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. A bearing bush 46 for supporting the rear part of the tool holder 23 is held in the upper through hole 45. A lower through hole 47 with a smaller diameter than the upper through hole 45 is formed on the lower left side below the upper through hole 45.

[0067] A groove 48 is formed across the entire circumference on the radially outer side of the bearing bush 46 and the outer peripheral surface of the bearing retainer 43. An O-ring 49 is held within the groove 48. The O-ring 49 presses against the inner peripheral surface of the rear cylinder 22, sealing the rear cylinder 22 and the bearing retainer 43. Therefore, the space between the outer casing 3 and the inner casing 40 is divided front and back by the O-ring 49. On the front side of the O-ring 49, the front of the space between the tool holder 23 and the outer casing 3 is sealed by an oil seal 25.

[0068] The inner rib 50 is formed facing forward on the front surface of the bearing retainer 43. Also, Figure 8As shown, the inner rib 50 is formed in an arc shape when viewed from the front, surrounding the lower half of the gear 38 protruding from the upper through-hole 45 from below. The front end of the inner rib 50 overlaps with the gear 38 radially. However, the left side of the inner rib 50 becomes a semi-circular portion 51 that surrounds the lower through-hole 47 from the outside. The front surface of the bearing retainer 43, surrounded by the O-ring 49, is divided vertically by the inner rib 50. The left and right ends of the inner rib 50 become inclined portions 50a, 50a that recede upwards. The front end of the middle portion of the inner rib 50 is located at the position furthest forward from the bearing retainer 43.

[0069] On the other hand, such as Figure 9 As shown, in the outer casing 3, an outer rib 52 is formed on the front inner surface of the rear cylinder portion 22, protruding rearward in opposition to 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 casing 40, and deforms at its rear end by being pressed against the front end of the inner rib 50, thus becoming a rib tightly attached to the inner rib 50 (a so-called crushing rib). 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 are inclined in shape as they move downward, and are consistent with the inclined portions 50a, 50a of the left and right ends of the inner rib 50.

[0070] Therefore, in the state where 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, the space inside the outer casing 3 and in front of the O-ring 49 is divided vertically by the partition wall 54. The upper side of the partition wall 54 becomes a front grease chamber 55, separated by the oil seal 25 and the O-ring 49. The front grease chamber 55 communicates with the rear grease chamber 56 inside the inner casing 40 through a lower through-hole 47, etc. The front grease chamber 55 and the rear grease chamber 56 constitute the drive mechanism receiving area (hereinafter referred to as the "receiving area") T.

[0071] The main body 44 is a hexagonal cylindrical shape when viewed from the front, slightly smaller than the bearing retaining part 43. Multiple heat sinks 57, 57… are erected on the left and right side surfaces of the main body 44. Each heat sink 57 extends vertically and is erected at predetermined intervals in the front-to-back direction. Figure 11As shown, the outer edge of each heat sink 57 is close to the inner surface of the rear cylinder 22. Multiple front exhaust ports 58, 58… extending in the front-rear direction are formed on the outer side of the protruding heat sink 57 and on the left and right side surfaces of the rear cylinder 22, respectively. When viewed from above, the left and right front exhaust ports 58 are arranged facing each other across the axis of the output shaft 10.

[0072] A front flange 59, which is 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.

[0073] like Figure 3 and Figure 11 As shown, the rear housing 42 has a rear through-hole 65 at approximately its center. The output shaft 10 passes through the rear through-hole 65. A bearing 66 for 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.

[0074] The front end of the rear housing 42 has a rear flange 68 that is quadrilateral when viewed from the front, the same as the front flange 59 of the main body 44. Four semi-circular notches 69, 69... are also formed at the four corners of the rear flange 68.

[0075] The front flange 59 and the rear flange 68 are clamped together in a rear-overlapping state between the rear cylinder portion 22 of the outer casing 3 and the connecting portion 6 of the motor housing 4. For example... Figure 5 , Figure 7 and Figure 9 As shown, four threaded fastening portions 70, 70... extending outwards from the four corners when viewed from the front are formed at the rear end of the rear cylinder portion 22. A circular threaded protrusion 71 protruding rearward is formed on the rear surface of each threaded fastening portion 70.

[0076] On the other hand, such as Figure 5 and Figure 8 As shown, at the four corners of the connecting portion 6, four internal thread portions 72, 72... are formed corresponding to each threaded fastening portion 70, each having an internal threaded hole. A circular recess 73 is formed on the front surface of each internal thread portion 72 to engage with the threaded protrusion 71. That is, as... Figure 12 As shown, each threaded protrusion 71 forms a concave-convex engagement with the circular recess 73 when fastened by the screw 8.

[0077] The front flange 59 and the 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 protrusion 71. In this state, each threaded fastening part 70 and internal thread part 72 is fastened from the front by screws 8, 8... threads. Thus, the outer shell 3 and the motor housing 4 are connected together, and the front flange 59 and the rear flange 68 are assembled together by pushing 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 housing 40 is positioned at the rear of the outer shell 3.

[0078] like Figure 3 and Figure 11 As shown, in this positioning state, a gap S is formed on the upper side between the rear cylinder portion 22 and the front and rear flanges 59 and 68. Therefore, the connecting portion 6, which houses the fan 18, communicates with the gap S behind the O-ring 49. The gap S communicates with the space between the rear cylinder portion 22 and the front housing 41, and communicates with the front exhaust port 58 via the heat sink 57.

[0079] like Figure 6 As shown, a groove 74 is formed across the entire circumference at the abutment portion on the front surface of the rear flange 68 where it abuts against the front flange 59. An O-ring 75 is held within the groove 74. In the assembled state of the inner housing 40, 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.

[0080] (Explanation of the rotation / impact switching unit)

[0081] For example Figure 6 , Figure 7 , Figure 11 and Figure 13 As shown, the rotation / impact switching unit 32 has two intermediate shafts, namely the first intermediate shaft 80 and the second intermediate shaft 81, on the lower side of the tool holder 23. The first intermediate shaft 80 and the second intermediate shaft 81 are parallel to each other and arranged parallel to the tool holder 23.

[0082] The rear end of the first intermediate shaft 80 on the left is rotatably supported on the rear housing 42 via 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 via a bearing 83. The first gear 84, which meshes with the pinion 17 of the output shaft 10, is rotatably mounted externally on the rear part of the first intermediate shaft 80. A gear-side engagement portion 85 is formed on the front outer periphery of the first gear 84.

[0083] A second gear 86 is formed at a position forward of the lower through hole 47 and at the front of the first intermediate shaft 80. The second gear 86 meshes with the gear 38 of the tool holder 23. A first spline portion 87 is formed in front of the first gear 84 and on the first intermediate shaft 80. A first clutch 88 is splined onto the first spline portion 87. The first clutch 88 is configured to rotate integrally with the first intermediate shaft 80 and move back and forth, and has a rear engagement portion 89 and a front engagement portion 90. In the retracted position, the first clutch 88 engages the rear engagement portion 89 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 via the first clutch 88.

[0084] A locking ring 91 is held in front of the first clutch 88 and within the lower through-hole 47 of the front housing 41. The locking ring 91 has four claws 92, 92… on its outer circumference. The locking ring 91 is forced into a retracted position by a front coil spring 93, where the claws 92 abut against the stop ring 94. In the forward position, the first clutch 88 disengages from the first gear 84, and the front engagement portion 90 engages with the claws 92 of the locking ring 91. 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. At this time, the tool holder 23 is also locked in rotation by the gear 38 that meshes with the second gear 86 of the first intermediate shaft 80. However, in the intermediate position between the forward and retracted positions, the first clutch 88 is not engaged with either the first gear 84 or the locking ring 91.

[0085] On the first intermediate shaft 80, a through hole 80a is formed along the diametrical direction on the rear side of the locking ring 91. On the axis of the first intermediate shaft 80, a central hole 80b communicating with the through hole 80a is formed extending to the rear end face. A pressure relief hole 76 is formed behind the bearing 82 and through the rear housing 42. The pressure relief hole 76 communicates with the central hole 80b.

[0086] Therefore, the increased pressure inside the inner housing 40 is released to the outside of the inner housing 40 through the through hole 80a, the axial hole 80b, and the pressure relief hole 76. An absorbent material 77, such as a sponge, is provided at the outlet of the pressure relief hole 76 to prevent grease leakage.

[0087] 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. A third gear 97, meshing with a pinion 17 of the output shaft 10, is integrally rotatably fixed to the rear of the second intermediate shaft 81. In front of the third gear 97, a flange sleeve 98 is externally mounted on the second intermediate shaft 81 in a separate and rotatable manner. A swashplate bearing 99 with an inclined axis is provided on the flange sleeve 98. An arm 100 is provided protruding upward from the outer ring of the swashplate bearing 99. The top end of the arm 100 is connected to the rear end of the piston cylinder 33. A coil spring 101 is sandwiched between the rear end of the piston cylinder 33 and the rear housing 42. The coil spring 101 applies force to the piston cylinder 33 in the forward position in the drilling mode described later. A flange side engagement portion 102 is formed at the front of the flange sleeve 98.

[0088] A second spline portion 103 is formed on the second intermediate shaft 81 in front of the flange sleeve 98. A second clutch 104 is splined onto 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 flange-side engagement portion 102 of the flange sleeve 98. Therefore, the rotation of the second intermediate shaft 81 is transmitted to the flange sleeve 98 via the second clutch 104. When the second clutch 104 moves forward, the clutch-side engagement portion 105 disengages from the flange-side engagement portion 102, so that the rotation of the second intermediate shaft 81 is no longer transmitted to the flange sleeve 98.

[0089] A mode switching mechanism 109 is provided below the first intermediate shaft 80 and the second intermediate shaft 81. Also, Figure 14 As shown, the mode switching mechanism 109 has two rods, namely the first rod 110 and the second rod 111, and also has a switching knob 116.

[0090] The first rod 110 and the second rod 111 are parallel to each other and are set parallel to the first intermediate axis 80 and the second intermediate axis 81.

[0091] The rear end of the first lever 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 110 has a first plate 112. The first plate 112 is a strip plate that extends parallel to the first lever 110 in the middle. The front and rear ends of the first plate 112 are bent toward the first lever 110 and are penetrated by the first lever 110. Therefore, the first plate 112 can move back and forth along the first lever 110. The front end of the first plate 112 engages with the outer periphery of the first clutch 88. A coil spring 113 is externally mounted on the first lever 110 in front of the first plate 112. The coil spring 113 applies force to the first plate 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 112.

[0092] The rear end of the second lever 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 111 has a second plate 114. The second plate 114 is a strip plate that extends parallel to the second lever 111 in the middle. The front and rear ends of the second plate 114 are bent toward the second lever 111 and are penetrated by the second lever 111. Therefore, the second plate 114 can move back and forth along the second lever 111. The front end of the second plate 114 engages with the outer periphery of the second clutch 104. A coil spring 115 is externally mounted on the second lever 111 in front of the second plate 114. The coil spring 115 applies force to the second plate 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 114.

[0093] The positions of plate 112 and plate 214 can be changed using the switching knob 116. For example... Figure 15 As shown, the switching knob 116 is configured to rotate towards the lower surface of the rear cylinder 22. Figure 3 , Figure 11 As shown, the switching knob 116 protrudes into the inner housing 40 through a bottom through-hole 117 located on the lower surface of the main body 44 of the front housing 41. Two 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 112 from the rear, and the second eccentric pin 119 engages with the middle portion of the second plate 114 from the rear.

[0094] Therefore, by rotating the switching knob 116, the front and rear positions of the first plate 112 and the second plate 114 can be switched via the first eccentric pin 118 and the second eccentric pin 119. That is, the operation mode can be switched to drilling mode, hammer drilling mode, hammering mode (rotation lock), and hammering mode (neutral).

[0095] (Instructions for hammer drilling operations)

[0096] Switch knob 116 to drilling mode. The first eccentric pin 118 is then in the fully retracted position, and the first clutch 88, together with the first plate 112, is in the retracted position. Therefore, rotation of the first gear 84 is transmitted to the first intermediate shaft 80 via the first clutch 88. Then, rotation of the first intermediate shaft 80 is transmitted from the second gear 86 to the tool holder 23 via gear 38.

[0097] On the other hand, the second eccentric pin 119 is in the forward position, and the second clutch 104 and the second plate 114 are also in the forward position. Therefore, the rotation transmitted from the output shaft 10 to the second intermediate shaft 81 is no longer transmitted to the flange sleeve 98.

[0098] Therefore, when the trigger 14 is pressed to turn on the switch 13, the drive motor 9 rotates the output shaft 10. This causes the tool holder 23 to rotate via the first intermediate shaft 80, thereby rotating the drill bit B at the tip.

[0099] 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 112 and the first clutch 88 are still in the retracted position.

[0100] On the other hand, the second eccentric pin 119 retracts from the forward position to the intermediate position, and the second clutch 104 and the second plate 114 are together in the retracted position. Therefore, the rotation of the second intermediate shaft 81 is transmitted to the flange sleeve 98 through the second clutch 104.

[0101] Therefore, when the trigger 14 is pressed, driving the motor 9, the tool holder 23 rotates via the first intermediate shaft 80, thereby rotating the drill bit B at the tip. Simultaneously, the flange 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 drill bit B via the striker 35.

[0102] Next, switch knob 116 to hammer mode (rotation lock). The first eccentric pin 118 is then in its forward position. The first clutch 88, together with the first plate 112, is in the forward position and engaged with the locking ring 91. Therefore, rotation of the first gear 84 is not transmitted to the first intermediate shaft 80, and rotation of the tool holder 23 is locked together with the first intermediate shaft 80.

[0103] On the other hand, the second eccentric pin 119 is in the final retracted position, and the second clutch 104 is still in the retracted position. Therefore, the rotation of the second intermediate shaft 81 is transmitted to the flange sleeve 98 via the second clutch 104.

[0104] 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, so that the hammer 34 impacts the drill bit B via the striker 35.

[0105] Furthermore, when the first clutch 88 advances, it sometimes abuts against the rear surface of the pawl 92 of the locking ring 91 without engaging in the rotational direction. However, in this case, the locking ring 91 advances against the force of the coil spring 93. Therefore, when the first intermediate shaft 80 rotates due to friction with the first gear 84 and causes the first clutch 88 to rotate, the locking ring 91 retracts in the engagement phase and engages with the first clutch 88. Thus, the rotation of the first intermediate shaft 80 is locked.

[0106] Next, switch knob 116 to hammer mode (neutral). 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 112 and disengages from the locking ring 91. However, the first clutch 88 is in the intermediate position, 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, together with the first intermediate shaft 80, becomes freely rotating.

[0107] On the other hand, the second eccentric pin 119 advances from the final retracted position to the intermediate position, and the second clutch 104 and the second plate 114 are in the retracted position together. Therefore, the rotation of the second intermediate shaft 81 is transmitted to the flange sleeve 98 via the second clutch 104.

[0108] Therefore, when the trigger 14 is pressed to drive the motor 9, the piston cylinder 33 reciprocates in a free state when the tool holder 23 is in a free state, so that the hammer 34 impacts the drill bit B via the striker 35.

[0109] Thus, when the hammer drill 1 operates in each operating mode, the fan 18 rotates due to the rotation of the output shaft 10. External air is then drawn into the motor housing 7 of the motor housing 4 through the rear air inlet 16 and moves forward to cool the motor 9. This cooling air flows into the connecting portion 6, and a portion is discharged to the outside through the rear exhaust port 20. Another portion moves forward within the connecting portion 6, passing through the gap S between the rear cylinder portion 22 and the front and rear flanges 59, 68, and flows into the rear cylinder portion 22. Then, the cooling air passes through the outer space of the inner housing 40 and is discharged from the front exhaust port 58. At this time, the contact between the cooling air and the front housing 41 suppresses the temperature rise of the front housing 41 caused by the heat generated by the drive mechanism 30. In particular, since the cooling air flows along the heat sink 57, the heat of the front housing 41 is effectively dissipated.

[0110] On the other hand, the receiving area T is filled with grease. In particular, since the front grease chamber 55 in the front cylinder 21 is a narrow space that saves useless space through the partition wall 54, the grease filling rate in the front grease chamber 55 is high. Therefore, grease that has splashed off from the rotating / impact action part 31 can easily re-adhere to the gear 38 and the like.

[0111] (The effects of the invention related to the division of the inner shell)

[0112] The hammer drill 1 described above has a motor 9, a cylindrical tool holder 23, a drive mechanism 30, and a flange sleeve 98 (an example of a rotation conversion component) within a housing 2. The tool holder 23 is used to mount a drill bit B at its top and is rotatable. The drive mechanism 30 can perform rotational movements of the tool holder 23 and / or impact movements of the drill bit B. The flange sleeve 98 is disposed within the drive mechanism 30 and can convert the rotation of the output shaft 10 of the motor 9 into the impact movement of the drill bit B. Furthermore, the hammer drill 1 has an inner housing 40 that supports the drive mechanism 30 and supports the tool holder 23 via a bearing 46 (an example of a first bearing), and supports the output shaft 10 via a bearing 66 (an example of a second bearing). Furthermore, the inner housing 40 is divided into a front housing 41 and a rear housing 42, which are connected in the axial direction of the tool holder 23. The front housing 41 is used to hold the bearing 46, and the rear housing 42 is separately formed from the front housing 41 and is used to hold the bearing 66. An O-ring 49 (an example of a sealing component) is provided on the front housing 41 to seal the outer space of the inner housing 40 within the housing 2.

[0113] According to this structure, since the inner housing 40 is divided into front and rear parts and an O-ring 49 is provided on the front housing 41, an inner housing 40 with a reduced housing area T can be formed on the rear side of the O-ring 49. Therefore, it also helps to make the product size more compact. In addition, since the cooling air of the motor 9 can be guided to the outside of the inner housing 40, a suitable cooling effect can be obtained for the drive mechanism 30.

[0114] The flange sleeve 98 is housed within the front housing 41. Therefore, the heat generated by the movement of the flange sleeve 98 can be effectively cooled by the front housing 41.

[0115] The O-ring 49 is positioned forward of the flange sleeve 98. Therefore, the outer space of the inner housing 40, which allows cooling airflow, is formed radially outward of the flange sleeve 98.

[0116] O-ring 49 is located radially outside of bearing shell 46. Therefore, the position of O-ring 49 is close to the foremost part of inner housing 40, which ensures a larger outer space.

[0117] An airflow path is formed radially outward of the flange sleeve 98 in the outer space. Therefore, heat transferred from the flange sleeve 98 can be effectively cooled from the outside of the inner housing 40.

[0118] The front housing 41 is made of metal. Therefore, it can effectively dissipate heat transferred to the inner housing 40.

[0119] An O-ring 75 (an example of a sealing component for the connection surface) is provided on the connection surface between the front housing 41 and the rear housing 42. Therefore, even if the inner housing 40 is divided into two parts, a tight seal can be ensured.

[0120] The drive mechanism 30 has two intermediate shafts parallel to the axis of the tool holder 23, namely a first intermediate shaft 80 and a second intermediate shaft 81. The first intermediate shaft 80 transmits the rotation of the output shaft 10 to the tool holder 23, while the second intermediate shaft 81 converts the rotation of the output shaft 10 into the impact action of the drill bit B through the flange sleeve 98. That is, by having the first intermediate shaft 80 share the function of rotation transmission and the second intermediate shaft 81 share the function of impact transmission, the first intermediate shaft 80 and the second intermediate shaft 81 can be shortened axially, respectively. Therefore, it contributes to the overall compactness of the drive mechanism 30.

[0121] Heat sinks 57 are formed on the outer surface of the front housing 41. Therefore, heat can be effectively dissipated from the front housing 41.

[0122] The motor 9 is configured with its output shaft 10 extending along the axis of the tool holder 23. A fan 18 is mounted on the output shaft 10. An air inlet 16 is located on the rear side of the housing 2, and a front exhaust port 58 (an example of an exhaust port) is located on the front side. The air inlet 16 and the front exhaust port 58 face each other across the axis of the output shaft 10. Therefore, the inner housing 40 can be cooled in a balanced and effective manner.

[0123] Furthermore, the following modifications can be made to the invention relating to the division of the inner shell.

[0124] The sealing components located on the front housing can also be sealing components other than O-rings. Multiple sealing components can be installed.

[0125] The front housing may not be made entirely of metal, but only partially; for example, only the retaining portion of the bearing supporting the tool holder may be made of metal. However, the front housing can be made of resin. The rear housing can also be made of metal.

[0126] The assembly of the front and rear housings is not limited to the structure described above, where the outer shell and motor housing clamp each other. Threaded fastening, etc., can also be used.

[0127] The airflow path structure of the outer space of the front housing is not limited to the above-described manner. The position and shape of the heat sink can be changed. The heat sink can also be omitted.

[0128] The position and number of air inlets and outlets can be appropriately changed. For example, the air inlets and outlets can be reversed to cool the inner housing before cooling the motor.

[0129] The intermediate shaft can be one instead of two.

[0130] (The effects of the invention related to the partition walls separating the containment areas)

[0131] The hammer drill 1 (an example of an impact tool) described above has a motor 9, a tool holder 23, a drive mechanism 30, and an inner housing 40 within a housing 2. The tool holder 23 can mount a drill bit B at its top; the drive mechanism 30 can impact the drill bit B; and the inner housing 40 supports the drive mechanism 30 within the housing 2. Furthermore, the hammer drill 1 can form a space including a receiving area T within the housing 2 by means of the housing 2, the inner housing 40, and an O-ring 49 (an example of a sealing member) sandwiched between the housing 2 and the inner housing 40. A partition wall 54 is provided within the housing 2 to separate the receiving area T from the remaining space.

[0132] According to this structure, even without using separate guide components, the partition wall 54 can be used to eliminate unnecessary space and reduce the housing area T. Therefore, manufacturing costs and assembly time can be reduced, while the grease filling rate can be increased.

[0133] The partition wall 54 is formed by the abutment of the outer rib 52 and the inner rib 50 respectively formed on the outer shell 3 (an example of the shell) and the inner shell 40. Therefore, a reasonable structure is provided in which the partition wall 54 is formed at the same time as the outer shell 3 and the inner shell 40 are assembled.

[0134] The outer rib 52 (an example of a rib on the shell side) is deformed by being pressed against the inner rib 50 (an example of a rib on the inner shell side) and becomes a rib that fits tightly against the inner rib 50. Therefore, even though the outer rib 52 and the inner rib 50 are in close contact, the sealing is ensured by the abutting of the ribs to form a partition wall 54.

[0135] The outer shell 3 is made of resin, and the front shell 41 of the inner shell 40 is made of metal. Therefore, the rigidity of the inner shell 40 can be ensured while maintaining the tight fit between the outer rib 52 and the inner rib 50.

[0136] The motor 9 is configured with its output shaft 10 parallel to the axis of the tool holder 23. The drive mechanism 30 has a first intermediate shaft 80, which is parallel to the tool holder 23 and is used to transmit rotation of the output shaft 10. The first intermediate shaft 80 has a gear 38 that transmits rotation to the tool holder 23 and is supported by the inner housing 40. The inner rib 50 forms a structure that covers part of the gear 38. Therefore, a partition wall 54 can be formed on the outside of the gear 38, thereby facilitating the re-adhesion of grease.

[0137] The inner housing 40 has a bearing retainer 43 that holds a bearing bush 46 for supporting the tool holder 23, and an inner rib 50 is formed protruding from the bearing retainer 43. Therefore, the inner rib 50 can be easily formed using the bearing retainer 43.

[0138] The front end of the inner rib 50 protrudes to the foremost position of the inner shell 40. Therefore, it can easily mate with the outer rib 52.

[0139] Furthermore, the invention relating to the partition walls separating the containment areas can be modified as follows.

[0140] The anterior-posterior lengths of the inner and outer ribs are not limited to the methods described above. The anterior-posterior lengths of the inner and outer ribs can be significantly different.

[0141] The partition walls are not limited to being formed by the abutting of ribs against each other. Ribs that abut against the surface of the other can be formed only on either the outer shell or the inner shell.

[0142] The partition shape formed by the partition wall is not limited to the above-described manner. Instead of forming a semi-circle that surrounds the tool holder and gear, a planar partition wall extending in the left-right direction can be formed.

[0143] The location of the partition wall is not limited to the above-described manner. It can be matched to the shape of the outer shell and inner shell, and located on the upper or lower side than in the above-described manner.

[0144] This invention is not limited to hammer drills. It can be applied to other impact tools such as electric hammers.

[0145] As an impact tool, it is not limited to a structure that uses an intermediate shaft (which can be a single shaft) and a rotary conversion component to reciprocate the piston cylinder. For example, it could be an impact tool that uses a crank mechanism and a connecting rod to reciprocate the piston cylinder.

[0146] (The effects of the invention involved in the assembly of the outer casing, motor housing, and inner casing)

[0147] The hammer drill 1 (an example of an impact tool) described above has a motor 9, a cylindrical tool holder 23, a drive mechanism 30, and an inner housing 40 within a housing 2. The tool holder 23 can mount a drill bit B at its top; the drive mechanism 30 can impact the drill bit B; and the inner housing 40 supports the drive mechanism 30. Furthermore, the housing 2 has a front outer housing 3 and a motor housing 4, which is assembled to the rear of the outer housing 3 to house the motor 9. The outer housing 3, motor housing 4, and inner housing 40 are connected together along the axial direction of the tool holder 23. Additionally, a threaded protrusion 71 for threading the outer housing 3 and motor housing 4 protrudes towards the motor housing 4 on the outer housing 3. The motor housing 4 and inner housing 40 are positioned by engaging with the threaded protrusion 71.

[0148] According to this structure, since the outer shell 3 and the motor housing 4 are not integrally joined with a concave-convex joint, the configuration and appearance of internal components are less likely to be affected. Furthermore, the motor housing 4 and the inner housing 40 can be easily positioned relative to the outer shell 3, which has threaded protrusions 71. Therefore, the outer shell 3, motor housing 4, and inner housing 40 can be assembled with high precision while ensuring design freedom.

[0149] It is provided with four threaded protrusions 71. Therefore, it can reliably position itself in the rotational direction.

[0150] The inner housing 40 is held between the outer housing 3 and the motor housing 4. Therefore, the inner housing 40 can be positioned using the outer housing 3 and the motor housing 4.

[0151] The inner housing 40 is pressed against the outer housing 3 and the motor housing 4 from both the front and rear sides. Therefore, the inner housing 40 can be firmly fixed between the outer housing 3 and the motor housing 4.

[0152] The inner housing 40 is divided into two parts along the axial direction of the tool holder 23. Therefore, the rear housing 42 can be made of resin to achieve weight reduction.

[0153] The threaded protrusion 71 is cylindrical, and the engaging part of the inner housing 40 that engages with the threaded protrusion 71 is a semi-circular notch 69. Therefore, the notch 69 can be reliably positioned by engaging with the threaded protrusion 71.

[0154] A threaded protrusion 71 is formed on the side of the housing 3, and an internal thread 72 is formed on the motor housing 4. This internal thread 72 engages with a screw 8 that passes through the threaded protrusion 71. Therefore, threaded fastening can be easily performed from the front of the housing 3.

[0155] The front housing 41 of the inner housing 40 is made of metal. Therefore, the rigidity of the inner housing 40 can be ensured.

[0156] Furthermore, the following modifications can be made to the invention relating to the assembly of the outer casing, motor housing, and inner casing.

[0157] It is possible that the threaded protrusion is not located on the outer casing, but on the motor housing, and is threaded from the rear of the motor housing. The housing on the other side that engages with the threaded protrusion can be formed into a shape other than a circular recess.

[0158] The threaded protrusion does not have to be cylindrical. Therefore, the engagement part provided in the inner housing does not need to form a semi-circular notch, as long as it is modified to match the shape of the threaded protrusion.

[0159] The inner housing does not have to be divided into two parts. A clamping part that is held between the outer housing and the motor housing can be formed on the integral inner housing.

[0160] The inner shell can be made entirely of metal or entirely of resin.

[0161] The number of threaded protrusions should be sufficient to position each housing in the rotational direction; at least two locations are required.

[0162] This invention is not limited to hammer drills. It can be applied to other impact tools such as electric hammers.

[0163] As an impact tool, it is not limited to a structure that uses an intermediate shaft (which can be a single shaft) and a rotary conversion component to reciprocate the piston cylinder. For example, it could be an impact tool that uses a crank mechanism and a connecting rod to reciprocate the piston cylinder.

[0164] The following describes common variations in the inventions.

[0165] The orientation of the motor is not limited to the front-to-back direction and can be changed appropriately.

[0166] The motor is not limited to a brushed motor; a brushless motor can also be used.

[0167] The power source doesn't have to be a commercial power supply; it can be a battery pack.

[0168] The selectable action modes are not limited to four. The position of the switching knob can also be changed appropriately.

[0169] The impact action can also be a structure where the piston reciprocates within a fixed cylinder, rather than a piston cylinder. Alternatively, it can be a structure without a striker, where the hammer directly impacts the drill bit.

[0170] Furthermore, the following invention can be extracted from the above method.

[0171] (Another invention 1)

[0172] An impact tool, characterized in that,

[0173] The housing contains a motor, a cylindrical tool holder, a drive mechanism, and an inner housing.

[0174] The tool holder can be used to mount a drill bit at the top;

[0175] The drive mechanism can impact the drill bit;

[0176] The inner housing is used to support the drive mechanism.

[0177] The housing has a front outer housing and a motor housing. The outer housing, the motor housing, and the inner housing are connected together along the axial direction of the tool holder. The motor housing is assembled to the rear of the outer housing to house the motor.

[0178] On either the outer casing or the motor housing, a threaded protrusion for threading the outer casing and the motor housing is formed to protrude to the other side.

[0179] The housing on the other side and the inner housing are positioned by engaging with the threaded protrusion.

[0180] (Another invention 2)

[0181] The impact tool according to another invention 1 is characterized in that,

[0182] At least two of the aforementioned threaded protrusions are provided.

[0183] (Another invention 3)

[0184] The impact tool according to another invention 1 or 2 is characterized in that,

[0185] The inner housing is held between the outer housing and the motor housing.

[0186] (Another invention 4)

[0187] The impact tool according to another invention 3 is characterized in that...

[0188] The inner housing is pushed from both the front and rear sides by the outer housing and the motor housing.

[0189] (Another invention 5)

[0190] The impact tool according to any one of inventions 1 to 4 is characterized in that,

[0191] The inner housing is divided into two parts in the axial direction.

[0192] (Another invention 6)

[0193] The impact tool according to any one of inventions 1 to 5 is characterized in that,

[0194] The threaded protrusion is cylindrical, and the engaging part of the inner shell that engages with the threaded protrusion is a semi-circular notch.

[0195] (Another invention 7)

[0196] The impact tool according to any one of the other inventions 1 to 6 is characterized in that,

[0197] The threaded protrusion is formed on the side of the outer casing, and an internal thread is formed on the motor housing, which engages with a screw that passes through the threaded protrusion.

[0198] (Another invention 8)

[0199] The impact tool according to any one of the other inventions 1 to 7 is characterized in that at least a portion of the inner housing is made of metal.

Claims

1. A hammer drill, characterized in that, The housing contains a motor, a cylindrical tool holder, a drive mechanism, a rotary conversion component, and an inner housing. The tool holder is used to mount the drill bit at the top and is rotatable; The drive mechanism can perform the rotation of the tool holder and / or the impact of the drill bit; The rotation conversion component is disposed in the drive mechanism and can convert the rotation of the motor's output shaft into the impact action of the drill bit; The inner housing supports the drive mechanism, and supports the tool holder via a first bearing and the output shaft via a second bearing. The inner housing is divided into a front housing and a rear housing, and is formed by connecting the front housing and the rear housing in the axial direction of the tool holder. The front housing is used to hold the first bearing; the rear housing is separately formed from the front housing and is used to hold the second bearing. A sealing component is provided on the front housing, which is used to seal the outer space of the inner housing within the housing. The rotary conversion component is housed within the front housing. The sealing component is positioned forward of the rotary conversion component.

2. The hammer drill according to claim 1, characterized in that, The front housing has a bearing retaining portion on a front side and a main body portion on a rear side, wherein the bearing retaining portion is used to retain the first bearing, and the main body portion extends rearward from the bearing retaining portion. A sealing component is provided on the bearing retaining portion, which is used to seal the outer space of the inner housing within the housing. The rotary conversion component is housed within the main body.

3. The hammer drill according to claim 1 or 2, characterized in that, The sealing component is located radially outside the first bearing.

4. The hammer drill according to claim 1 or 2, characterized in that, A groove is formed across the entire circumference of the outer peripheral surface of the front housing, and the sealing component is an O-ring held in the groove.

5. The hammer drill according to claim 1 or 2, characterized in that, An airflow path is formed radially outward of the rotary conversion component in the outer space.

6. The hammer drill according to claim 1 or 2, characterized in that, The front housing is made of metal.

7. The hammer drill according to claim 1 or 2, characterized in that, A sealing component is provided on the connection surface between the front housing and the rear housing.

8. The hammer drill according to claim 1 or 2, characterized in that, The drive mechanism has two intermediate shafts parallel to the axis of the tool holder. One intermediate shaft transmits the rotation of the output shaft to the tool holder, while the other intermediate shaft converts the rotation of the output shaft into the impact action of the drill bit through the rotation conversion component.

9. The hammer drill according to claim 1 or 2, characterized in that, Heat sinks are formed on the outer surface of the front housing.

10. The hammer drill according to claim 1 or 2, characterized in that, The motor is configured such that the output shaft extends along the axial direction of the tool holder, a fan is provided on the output shaft, an air inlet is provided on either the front or rear side of the housing, and an exhaust port is provided on the other side, with the air inlet and the exhaust port facing each other across the axial direction of the output shaft.

11. The hammer drill according to claim 1 or 2, characterized in that, In the axial direction of the tool holder, the front housing is formed to be longer than the rear housing.

12. The hammer drill according to claim 1 or 2, characterized in that, The first bearing is a bush bearing.

13. The hammer drill according to claim 1 or 2, characterized in that, The second bearing is a ball bearing.

14. The hammer drill according to claim 1 or 2, characterized in that, The housing has a front outer housing and a motor housing. The outer housing, the motor housing, and the inner housing are connected together along the axial direction of the tool holder. The motor housing is assembled to the rear of the outer housing to house the motor. On either the outer casing or the motor housing, a threaded protrusion for threaded fastening of the outer casing and the motor housing is formed protruding to the other side. The inner housing is positioned by engaging with the threaded protrusion.

15. The hammer drill according to claim 14, characterized in that, The inner housing is held between the outer housing and the motor housing.

16. The hammer drill according to claim 15, characterized in that, The inner housing is pushed from both the front and rear sides by the outer housing and the motor housing.

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