JP6426028B2 - Impact tool - Google Patents

Description

  The present invention relates to an impact tool such as a hammer drill having an impact mechanism of a tip tool.

  An impact tool such as a hammer drill has a motor, a reciprocating member such as a piston and a cylinder, an impactor interlocking with the reciprocating member, and a conversion member for converting the rotation of the motor into the longitudinal movement of the reciprocating member in a housing The reciprocating member is interlocked via the conversion member in accordance with the drive of the motor, and the impact tool directly or indirectly strikes the tip tool by the interlocking member. A support member (inner housing) for holding the output shaft of the motor and the cylinder portion (final output shaft) of the striking mechanism respectively through bearings in the housing between the motor and the striking mechanism as disclosed in Patent Document 1 Here, in order to reduce the weight, the support member is made of resin except for a bearing such as a metal bearing for supporting the cylinder portion, and is manufactured by integrally molding the bearing.

Patent No. 5007926 gazette

  As described above, when the inner housing is made of resin except for the bearings, the heat generation of the bearings may deform the resin around the inner housing, which may lead to misalignment of the cylinder or the like and a decrease in durability.

  Therefore, in the present invention, while maintaining the weight reduction by making the inner housing made of resin, it is possible to suppress the deformation of the inner housing due to the heat generation of the bearing and to preferably prevent the misalignment and the deterioration of durability. It is intended to provide a tool.

In order to achieve the above object, the invention according to claim 1 is characterized in that the motor and the striking mechanism are accommodated in a housing that accommodates the motor and a striking mechanism disposed in front of the motor and operated by driving the motor. An impact tool provided with an inner housing for holding the output shaft of the motor and the final output shaft of the striking mechanism respectively through bearings, the inner housing, the bearing holding portion of the final output shaft being metal, and the other portions Are formed of resin to connect the metal forming portion and the resin forming portion, while the fan is provided on the output shaft of the motor, and the air flow from the fan is outside the metal forming portion in the housing. It is characterized in that an air passage which is allowed to pass through is formed .
In order to achieve the above object, the invention according to claim 2 is characterized in that the motor and the striking mechanism are accommodated in a housing that accommodates the motor and a striking mechanism disposed in front of the motor and operated by driving the motor. An impact tool provided with an inner housing for holding the output shaft of the motor and the final output shaft of the striking mechanism respectively through bearings, the inner housing, the bearing holding portion of the final output shaft being metal, and the other portions Are formed of resin and the metal forming portion and the resin forming portion are combined, while the resin forming portion is a through space in which the internal air penetrates in the front-rear direction and contacts the metal forming portion. it is characterized in that the formed.
The invention according to claim 3 is characterized in that in the configuration according to claim 1 or 2 , the metal forming portion and the resin forming portion are screwed together.
The invention according to a fourth aspect is characterized in that, in the configuration according to any one of the first to third aspects, the metal forming portion includes an abutting portion that abuts on the inner surface of the housing.
The invention according to claim 5 is characterized in that, in the configuration according to claim 1 or 2 , the metal forming portion is joined by integral molding with the resin forming portion.
The invention according to claim 6 is characterized in that, in the configuration according to claim 5 , the metal formation portion is provided with a retaining portion in the front-rear direction and a rotation preventing portion in the rotational direction.
The invention according to claim 7, in any one of the claims 1 to 6, the metal forming portions, is characterized in being formed of aluminum or magnesium.
Here, “aluminum” includes “aluminum alloy”, and “magnesium” includes “magnesium alloy”.
According to an eighth aspect of the present invention, in the configuration according to any one of the first to seventh aspects, the striking mechanism includes a piston cylinder for accommodating a striker, and a cylindrical tool holder serving as a final output shaft for holding the piston cylinder. And a conversion member for converting the rotation transmitted from the output shaft into a reciprocating motion in the back and forth direction of the piston cylinder, wherein the bearing is characterized by holding the tool holder.

According to the invention as set forth in claims 1 and 2 , the inner housing is formed by forming the holding portion of the final output shaft with a metal and the other portion with a resin and connecting the two to make the inner housing a resin. While maintaining the weight reduction by making it possible to make it possible to suppress the deformation of the inner housing due to the heat generation of the bearing, it is possible to preferably prevent the misalignment and the deterioration of the durability.
In particular, according to the first aspect of the present invention, in addition to the above-mentioned effects, it is possible to further enhance the heat dissipation effect of the metal forming portion by the air passage provided in the housing.
In particular, according to the second aspect of the present invention, in addition to the above-mentioned effects, the formation of the through space promotes heat radiation of the metal-formed portion, which makes it possible to more preferably prevent the deformation of the inner housing.
According to the third aspect of the invention, in addition to the effect of the first or second aspect , the metal forming portion and the resin forming portion can be easily coupled and separated by screw connection, and assemblability and repairability are improved. It becomes good.
According to the fourth aspect of the invention, in addition to the effect of any one of the first to third aspects , the rigidity of the inner housing can be enhanced by adopting the contact portion, and the output shaft and the final output shaft of the motor It is possible to accurately maintain the positional relationship with the
According to the fifth aspect of the invention, in addition to the effect of the first or second aspect , the metal forming portion can be bonded simultaneously with the formation of the resin forming portion.
According to the sixth aspect of the invention, in addition to the effect of the fifth aspect , the adoption of the retaining portion and the antirotation portion ensures that the integrally formed metal forming portion is integrated with the resin forming portion. it can.
According to the seventh aspect of the invention, in addition to the effect of any of the first to sixth aspects, the weight reduction of the metal-formed portion can be achieved by adopting aluminum or magnesium.
According to the eighth aspect of the invention, in addition to the effect of any one of the first to seventh aspects, weight reduction and durability maintenance of the inner housing also in the striking mechanism in which the final output shaft is a cylindrical tool holder It is possible to

It is a partial longitudinal cross-sectional view of a hammer drill. It is the sectional view on the AA line of FIG. It is an exploded perspective view of an inner housing. It is explanatory drawing of an inner housing, (A) is a center longitudinal cross-section, (B) shows a BB line cross section, respectively. It is a partial longitudinal cross-sectional view of the hammer drill of a modification. It is the CC sectional view taken on the line of FIG. It is a perspective view of the inner housing of a modification. It is a perspective view of a sleeve. It is explanatory drawing of the inner housing of a modification, (A) shows a center longitudinal cross section, (B) shows a DD sectional view, respectively. It is the EE sectional view taken on the line of FIG. It is a partial longitudinal cross-sectional view of the hammer drill of a modification. It is the FF sectional view taken on the line of FIG. It is the GG sectional view taken on the line of FIG. It is a top view of a hammer drill.

Hereinafter, embodiments of the present invention will be described based on the drawings.
FIG. 1 is a partial vertical cross-sectional view of a hammer drill which is an example of a striking tool, and FIG. 2 is a cross-sectional view taken along line A-A of FIG. The front housing 5 containing the striking mechanism 6 is connected from the rear with a plurality of bolts (not shown) to the front of the motor housing 2 housed in the), and the handle 7 housing the switch 8 is connected to the rear of the motor housing 2 Become. 9 is a trigger provided on the switch 8 and protruding forward. A motor cooling fan 10 is fixed to an output shaft 4 of the motor 3 and disposed in a fan storage chamber 11 formed in the front of the motor housing 2. Exhaust ports 12 and 12 are formed on the side surface and the lower surface of the motor housing 2 outside the fan accommodation chamber 11, and an intake port (not shown) is formed on the rear surface of the handle 7.

  An inner housing 13 is held inside the front housing 5. As shown in FIGS. 3 and 4, the inner housing 13 is an oblong plate fitted to the rear end of the front housing 5 and assembled between the motor housing 2 and the front housing 5 and protrudes forward. It consists of a rear holding portion 14 provided with a cylindrical portion 15 and a large diameter ring-shaped front holding portion 16 supported in front of the rear holding portion 14 by the cylindrical portion 15. The output shaft 4 of the motor 3 is supported by a ball bearing 17 which is a bearing held by the rear holding portion 14 of the inner housing 13, penetrates the rear holding portion 14, and protrudes into the front housing 5. A notch 18 is formed in the front and rear direction at the lower part of the cylindrical portion 15, and a U-shaped rib 19 in a front view is provided upright below the cylindrical portion 15 on the front surface of the rear holding portion 14.

In the inner housing 13, the rear holding portion 14 and the cylindrical portion 15 are integrally formed of resin, and the front holding portion 16 is made of metal (aluminum in this case) separate from the cylindrical portion 15. The front holding portion 16, which is a metal forming portion, is joined from the front by a pair of left and right screws 21, 21 to a pair of bosses 20, 20 provided on the left and right of the cylindrical portion 15 in the rear holding portion 14 which is a resin forming portion. Ru. Reference numeral 22 denotes a seat through which the screw 21 is penetrated to immerse the head, and reference numeral 23 denotes a hollow portion.
Further, a metal bearing 24 for pivotally supporting a tool holder 43 described later is press-fitted to the front holding portion 16. A step 25 for allowing the metal bearing 24 to abut and positioning the press-fit position is circumferentially provided at the inner peripheral rear end of the front holding portion 16 and the rear end 25a of the stepped portion 25 extends rearward on the inner peripheral side It is an inlay joint that is polymerized at the front end of the cylindrical portion 15. The front holding portion 16 is formed to have a diameter larger than that of the cylindrical portion 15, and forms an abutting portion 26 that abuts the inner surface of the front housing 5 in a state of being accommodated in the front housing 5 on the outer periphery.

  Furthermore, a through space 27 is formed in the upper portion of the inner housing 13 so as to penetrate the rear holding portion 14 including the cylindrical portion 15 back and forth. The through space 27 communicates with the fan chamber 11 of the motor housing 2 at the rear, and the front is closed by the front holder 16. Thus, part of the air flow generated by the fan 10 contacts the front holding portion 16 via the through space 27. The reference numeral 28 denotes a recessed groove recessed on the outer periphery of the rear holding portion 14, and the O ring 29 fitted here abuts against the inner periphery of the front housing 5 to make the space between the rear holding portion 14 and the front housing 5 It is supposed to seal.

  On the other hand, an intermediate shaft 30 is provided on the lower side of the output shaft 4 in the front housing 5. The intermediate shaft 30 is supported by a ball bearing 31 whose front end is held by the front inner surface of the front housing 5 and by a ball bearing 33 whose rear end is held by the bearing retainer 32. It is arranged in the front and back direction. The bearing retainer 32 is screwed to a rib 19 provided on the front surface of the rear holding portion 14, and at the rear end of the intermediate shaft 30 projecting between the bearing retainer 32 and the rear holding portion 14, the tip of the output shaft 4. A second gear 35 engaged with the provided first gear 34 is fixed.

  Furthermore, a third gear 36 is rotatably provided at the front of the intermediate shaft 30, and a boss sleeve 37 as a conversion member is rotatably provided at the rear of the intermediate shaft 30, The arm 39 is provided upward through a swash bearing 38 inclined from the axial center and protrudes into the tubular portion 15 through the notch 18. A clutch 40 is provided between the third gear 36 and the boss sleeve 37 so as to be integrally rotatable with the intermediate shaft 30 and movable back and forth by spline connection. The eccentric pin 42 of the switching lever 41 rotatably provided on the lower surface of the front housing 5 is engaged with the clutch 40, and the clutch 40 is moved back and forth by the eccentric motion of the eccentric pin 42 by the rotation operation of the switching lever 41. It can move to an advanced position in which only the third gear 36 is engaged, a retracted position in which only the boss sleeve 37 is engaged, and an intermediate position in which both the third gear 36 and the boss sleeve 37 are engaged It has become.

  And the striking mechanism 6 is equipped with the cylindrical tool holder 43 as a final output shaft which can mount the tip tool which is not shown in figure in the front end above the middle axis | shaft 30. As shown in FIG. The tool holder 43 is provided on the outer periphery of the middle portion by a metal bearing 24 whose front side portion is axially supported by the ball bearing 44 in the front housing 5 and whose rear end is held by the front holding portion 16 of the inner housing 13 The fourth gear 45 is engaged with the third gear 36 of the intermediate shaft 30. Further, at the rear of the tool holder 43, a piston cylinder 47 connected to the arm 39 by a connecting shaft 46 is accommodated so as to be movable back and forth, and inside the piston cylinder 47, a striker 49 is provided via an air chamber 48. It is housed so that it can move back and forth. An intermediate member 50 is provided in the tool holder 43 in front of the striker 49 so as to be able to abut on the rear end of the tip tool attached to the front end of the tool holder 43. Reference numeral 51 denotes an operation sleeve provided at the front end of the tool holder 43 for retaining the tip tool.

  In the hammer drill 1 configured as described above, when the trigger 9 is pressed to turn on the switch 8, the motor 3 is driven to rotate the output shaft 4, and the second gear 35 is engaged with the first gear 34. The intermediate shaft 30 is rotated via. At this time, if the forward position of the clutch 40 is selected by the operation of the switching lever 41, the rotation of the intermediate shaft 30 is transmitted to the tool holder 43 via the third gear 36 and the fourth gear 45, and the tool holder 43 holds it. It becomes a drill mode to rotate the tip tool. Further, when the retracted position of the clutch 40 is selected, the rotation of the intermediate shaft 30 is transmitted to the boss sleeve 37 and converted to the forward and backward rocking of the arm 39 through the swash bearing 38. Therefore, the piston cylinder 47 moves back and forth to interlock the striker 49, and a hammer mode is reached in which the tip tool is hit via the intermediate element 50. Then, if the intermediate position of the clutch 40 is selected, the rotation of the intermediate shaft 30 is transmitted to the third gear 36 and the boss sleeve 37, so that the hammer drill mode is set where the tip tool is struck with the rotation of the tool holder 43.

  Thus, even if the metal bearing 24 supporting the tool holder 43 generates heat due to the rotation of the tool holder 43 and the back and forth movement of the piston cylinder 47, this heat is transmitted to the outer metal front holding portion 16 and dissipated. The temperature rise of the cylindrical portion 15 made of resin does not occur excessively. Thus, deformation of the inner housing 13 can be suppressed. In particular, here, after the air taken in from the rear intake port by the rotation of the fan 10 accompanying the rotation of the output shaft 4 passes through the motor 3 and cools the motor 3, the exhaust port 12 passes through the fan storage chamber 11. As a part of this air passes through the penetration space 27 of the inner housing 13 and contacts the front holding portion 16, the heat dissipation of the front holding portion 16 is promoted.

  As described above, according to the hammer drill 1 of the above embodiment, the inner housing 13 is formed by the holding portion (here, the front holding portion 16) of the metal bearing 24 of the tool holder 43 by the metal and the other portion (the rear holding portion 14). By forming the front holding portion 16 and the rear holding portion 14 by respectively forming them with resin, it is possible to maintain the weight reduction by making most of the inner housing 13 made of resin, while maintaining the front holding. The deformation of the inner housing 13 due to the heat generation of the portion 16 can be suppressed, and the misalignment and the deterioration of the durability can be suitably prevented.

In particular, here, since the front holding portion 16 which is a metal forming portion and the rear holding portion 14 which is a resin forming portion are screwed together, the front holding portion 16 and the cylindrical portion 15 of the rear holding portion 14 can be easily made. It can be connected and separated, and assemblability and repairability are improved.
Further, since the front holding portion 16 includes the contact portion 26 that contacts the inner surface of the front housing 5, the rigidity of the inner housing 13 can be enhanced, and the positional relationship between the output shaft 4 of the motor 3 and the tool holder 43 can be obtained. It becomes accurate and maintainable.

Furthermore, heat dissipation of the front holding portion 16 is promoted by forming the through space 27 in which the internal air comes in contact with the front holding portion 16 in the rear holding portion 14 so that the inner housing 13 is deformed. It becomes possible to prevent more suitably.
In addition, the weight of the front holding portion 16 can be reduced by making the front holding portion 16 of aluminum.
The striking mechanism 6 converts the rotation transmitted from the output shaft 4 into the back and forth movement of the piston cylinder 47 in the back and forth direction of the piston cylinder 47 that accommodates the striker 49, the tool holder 43 that holds the piston cylinder 47, and The metal bearing 24 holds the tool holder 43 to maintain the weight reduction and durability of the inner housing 13 even in the striking mechanism 6 in which the final output shaft is the cylindrical tool holder 43. Can be

  In addition, in the inner housing of the said form, although the contact part of the front holding | maintenance part is continuously formed in the circumferential direction, it can also form intermittently. Further, the positions and the number of screws connecting the front holding portion and the rear holding portion can be changed as appropriate. Furthermore, the number and shape of the through spaces can be changed or omitted.

  On the other hand, in the above embodiment, the entire front holding portion 16 of the inner housing 13 is made of metal and the contact portion 26 on the outer periphery thereof is in contact with the inner surface of the front housing 5. However, the inner in the hammer drill 1A shown in FIGS. Like the housing 13A, only the holding portion of the metal bearing 24 in the front holding portion 16 may be made of metal. That is, the holding portion is a metal (in this case, aluminum) sleeve 52 into which the metal bearing 24 is press-fitted, and the outer front holding portion 16, the cylindrical portion 15 and the rear holding portion 14 are made of resin. The sleeve 52 which becomes a part is integrally molded with the resin formation part other than that. In the inner housing 13A, a bearing retainer is not used for holding the ball bearing 33 for supporting the rear end of the intermediate shaft 30, and the inner housing 13A is directly held by the rear holding portion 14.

  As shown in FIG. 8, the sleeve 52 has a pair of grooves 53 formed in the circumferential direction on the upper and lower outer peripheries which are retaining portions in the front and rear direction, and a pair of detents which are rotating in the left and right directions. The chamfered portions 54, 54 are formed, and a step 55 for positioning the metal bearing 24 is formed on the inner periphery of the rear end. Therefore, by setting the sleeve 52 in the mold of the inner housing 13A and integrally molding the resin, as shown in FIGS. 9 and 10, the resin enters the groove 53 and the resin is molded along the chamfered portion 54. As a result, they are integrated with the resin-formed portion in the state of being locked and locked. Here, a contact portion 26 made of resin is formed on the outside of the sleeve 52 and contacts the inner surface of the front housing 5. Further, the cylindrical portion 15 is formed longer in the circumferential direction to the left than in the circumferential direction when viewed from the front, and a through space 27 communicating with the fan accommodation chamber 11 is formed inside the entire cylindrical portion 15.

  Even in the hammer drill 1A configured as described above, even if the metal bearing 24 for supporting the tool holder 43 generates heat due to the rotation of the tool holder 43 and the back and forth movement of the piston cylinder 47, this heat is transmitted to the outer sleeve 52 Since the heat is radiated, the temperature of the tubular portion 15 does not rise excessively. Thus, deformation of the inner housing 13A can be suppressed. Also here, since the cooling air for the motor 3 contacts the sleeve 52 through the penetration space 27 of the inner housing 13A, the heat radiation of the sleeve 52 is promoted.

As described above, according to the hammer drill 1A of the modification, while maintaining the weight reduction by making most of the inner housing 13A made of resin, the core of the core is suppressed by suppressing the deformation of the inner housing 13A due to the heat generation of the metal bearing 24. Deviation or deterioration in durability can be suitably prevented.
In particular, here, since the sleeve 52 is bonded by integral molding with the other resin-formed portion, the sleeve 52 can be bonded simultaneously with the molding of the resin-formed portion.
Further, by providing the sleeve 52 with the groove 53 as the retaining portion and the chamfered portion 54 as the rotation preventing portion, the integrally molded sleeve 52 can be surely integrated with the resin forming portion.

  The sleeve may be made thicker, and the retaining portion and the detent portion may be protuberances or protrusions in the circumferential direction instead of the groove, or may be the retaining portion and the detent portion by axial protrusions or protrusions. And may be changed as appropriate. The penetration space may also be changed or omitted.

  In the hammer drill 1B shown in FIG. 11, the inner housing 13B has a structure in which the metal front holding portion 16 is connected to the resin rear holding portion 14 as in the embodiment of FIG. The upper side of the portion 14 is inclined forward, and the contact position of the O-ring 29 with the upper inner surface of the front housing 5 is set to the front of the form of FIG. 1. As a result, a communication space 56 communicating with the fan accommodation chamber 11 at the rear of the O-ring 29 is formed at the upper rear of the front housing 5.

  A thin portion 57 reaching the rear of the O-ring 29 above the communication space 56 is formed on the upper side of the front housing 5, and the inside of the thick portion 58 formed on the front side of the thin portion 57 is shown in FIG. As shown in 12 and 13, a pair of left and right air passages 59, 59 are formed. The air passage 59 is open at the rear end surface of the thick portion 58 and communicates with the communication space 56, while the front end is formed up to the front ends of the metal bearing 24 and the contact portion 26. It communicates with the outside through slit-like front exhaust ports 60, 60 formed on the upper surface. Therefore, a part of the air flow generated by the fan 10 is discharged from the communication space 56 through the air passages 59, 59 and the front exhaust ports 60, 60.

  On the other hand, although a short through space 27 is formed in the back and forth in the cylindrical portion 15 of the rear holding portion 14 here, a notch 61 is formed in the upper front end of the cylindrical portion 15. The space S in the front housing 5 sealed in the above-mentioned manner is communicated with the communication space 56 through the notch 61 and the through space 27. The notch 61 and the through space 27 form an internal pressure relief passage 62 for releasing the pressure buildup in the space S. Here, the grease filled in the front housing 5 communicates with the communication space 56 from the internal pressure relief passage 62. A filter 63 for closing the notch 61 is held between the front end of the cylindrical portion 15 and the front holding portion 16 so as not to leak inward. The filter 63 is formed of an air-permeable material such as a long sponge or felt on the left and right, and the movement of the filter 63 is restricted to the rear by a protrusion 64 provided to protrude forward from the inner surface of the rear end of the cylindrical portion 15 There is.

  By sandwiching the filter 63 between the cylindrical portion 15 and the front holding portion 16 in this manner, the number of parts can be reduced compared to the conventional structure in which the filter is pushed into the passage provided in the housing and covered with another part. It can be reduced. Further, since the internal pressure release passage 62 and the filter 63 are disposed on the upper side of the inner housing 13B, the grease is less likely to leak.

Even in the hammer drill 1B configured as described above, even if the metal bearing 24 supporting the tool holder 43 generates heat due to the rotation of the tool holder 43 and the back and forth movement of the piston cylinder 47, this heat is transmitted to the front holding portion 16 Since the heat is radiated, the temperature of the tubular portion 15 does not rise excessively. Thus, deformation of the inner housing 13B can be suppressed.
Then, a part of the air flow generated by the fan 10 passes from the communication space 56 through the air passages 59, 59 in the front housing 5 as described above, and is discharged from the front exhaust ports 60, 60. That is, the air can flow in the front housing 5 in contact with the contact portion 26 of the front holding portion 16 to effectively cool the front holding portion 16.

As described above, according to the hammer drill 1B of the modification, while maintaining the weight reduction by making most of the inner housing 13B made of resin, the deformation of the inner housing 13B due to the heat generation of the front holding portion 16 is suppressed. It is possible to preferably prevent misalignment and deterioration in durability.
Particularly in this case, the front housing 5 is provided with the air passages 59, 59 for passing a part of the air flow by the fan 10 to the outside of the front holding portion 16, so that the heat dissipation effect by the front holding portion 16 can be further enhanced. it can.

  In this modification, the form of the air passage is not limited to the above example, and the number of air passages and front exhaust ports may be increased or decreased, the cross sectional shape of the air passage may be changed, or the air located outside the front holding portion The front end portion of the passage can be extended in the circumferential direction of the front housing to form a long air flow passage passing outside the metal forming portion.

  And in common with the above-mentioned form and each modification, structures other than an inner housing are change suitably, and it provided not only a hammer drill but an inner housing holding an output shaft of a motor and a final output shaft of a striking mechanism. As long as it is a thing, this invention is applicable also to other striking tools, such as an electric hammer.

  1, 1A, 1B · · · hammer drill, 2 · · motor housing, 3 · · motor, 4 · output shaft, 5 · · front housing, 6 · · striking mechanism, 10 · · fan, 11 · fan storage chamber, 12 · · Exhaust port, 13, 13 A · · Inner housing, 14 · · · · · · · · · · · · · · · · · · · · · · · · · · · · 17, 31, 33, 44 · · · ball bearings, 24 · · · Metal bearings, 25, 55 · · · · · · · · · 26 · · · contact portion, 27 · · through space, 30 · · intermediate shaft, 34 · · first gear, 35 · · second gear, 36 · · third gear , 37 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Groove, 54 · · · · · · · · · · · · communication space, 57 · · · thin portion, 8 ... thick portion, 59 ... air passage, 60 ... front outlet 62 ... pressure release passage, 63 ... filter.

Claims (8)

An output shaft of the motor and a final output shaft of the striking mechanism are disposed between the motor and the striking mechanism in a housing that accommodates the motor and a striking mechanism disposed in front of the motor and operated by driving of the motor. An impact tool provided with an inner housing for holding the
The inner housing is formed by forming the holding portion of the bearing of the final output shaft with metal and the other portion with resin, and combining the metal forming portion and the resin forming portion ,
A striking tool provided with a fan on the output shaft of the motor to form an air passage in the housing for passing an air flow from the fan to the outside of the metal forming portion . An output shaft of the motor and a final output shaft of the striking mechanism are disposed between the motor and the striking mechanism in a housing that accommodates the motor and a striking mechanism disposed in front of the motor and operated by driving of the motor. An impact tool provided with an inner housing for holding the
The inner housing is formed by forming the holding portion of the bearing of the final output shaft with metal and the other portion with resin, and combining the metal forming portion and the resin forming portion,
A striking tool characterized in that a through space is formed in the resin-formed portion so that internal air penetrates in the front-rear direction and contacts the metal-formed portion . The impact tool according to claim 1 or 2 , wherein the metal forming portion and the resin forming portion are screwed together. The impact tool according to any one of claims 1 to 3, wherein the metal forming portion comprises an abutment portion that abuts on an inner surface of the housing. The impact tool according to claim 1 or 2 , wherein the metal forming portion is joined by integral molding with the resin forming portion. The impact tool according to claim 5 , characterized in that the metal-formed portion is provided with a forward and backward direction retaining part and a rotational direction preventing part. The impact tool according to any one of claims 1 to 6 , wherein the metal forming portion is formed of aluminum or magnesium. The striking mechanism includes a piston cylinder for accommodating a striker, a cylindrical tool holder serving as the final output shaft for holding the piston cylinder, and rotation transmitted from the output shaft in the front-rear direction of the piston cylinder The impact tool according to any one of claims 1 to 7 , further comprising: a conversion member for converting into a reciprocating motion, wherein the bearing holds the tool holder.

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