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CN-114939849-B - Hammer drill

CN114939849BCN 114939849 BCN114939849 BCN 114939849BCN-114939849-B

Abstract

The invention provides a hammer drill. The hammer drill (1) has a motor (9), a tool holder (23), a drive mechanism (30), a flange sleeve (98) capable of converting rotation of an output shaft (10) into impact action of a drill bit (B), and an inner housing (40) for supporting the drive mechanism and supporting the tool holder (23) through a bearing bush (46), and supporting the output shaft (10) through a bearing (66). The inner housing is divided into a front housing (41) and a rear housing (42), which are formed by connecting the front housing and the rear housing in the axial direction of the tool holder, the front housing being for holding the bearing bush, and the rear housing being formed separately from the front housing and for holding the bearing. An O-ring (49) is provided on the front housing for sealing the outside space of the inner housing within the housing. Accordingly, even if the inner case is partitioned to form the driving mechanism accommodation area, the driving mechanism can be made compact, and an appropriate cooling effect of the driving mechanism can be obtained.

Inventors

  • MACHIDA YOSHITAKA
  • Yoshikane Yoshinobu

Assignees

  • 株式会社牧田
  • 株式会社牧田

Dates

Publication Date
20260421
Application Date
20220215
Priority Date
20210215

Claims (16)

  1. 1. A hammer drill is characterized in that, The motor, the tubular tool holder, the driving mechanism, the rotation conversion member and the inner housing are provided in the housing, The tool holder is used for mounting a drill bit on the top end and can rotate; the driving mechanism can perform a rotation action of the tool holder and/or a percussion action of the drill bit; The rotation conversion member is provided to the driving mechanism and is capable of converting rotation of an output shaft of the motor into a striking motion of the drill; The inner housing is used for supporting the driving mechanism, the tool holder is supported by a1 st bearing, the output shaft is supported by a 2 nd 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 an axial direction of the tool holder, wherein the front housing is configured to hold the 1 st bearing, the rear housing is divided from the front housing and the rear housing is configured to hold the 2 nd bearing, A sealing member for sealing an outer space of the inner case within the case is provided on the front case, The rotation conversion member is accommodated in the front case, The seal member is disposed in front of the rotation conversion member.
  2. 2. The hammer drill according to claim 1, wherein, The front housing has a front bearing holding portion for holding the 1 st bearing and a rear main body portion extending rearward from the bearing holding portion, A sealing member for sealing an outer space of the inner housing in the housing is provided on the bearing holding portion, The rotation conversion member is housed in the main body.
  3. 3. Hammer drill according to claim 1 or 2, characterized in that, The seal member is located radially outward of the 1 st bearing.
  4. 4. Hammer drill according to claim 1 or 2, characterized in that, A groove is formed on the outer peripheral surface of the front housing across the entire circumference, and the sealing member is an O-ring held in the groove.
  5. 5. Hammer drill according to claim 1 or 2, characterized in that, An air flow path is formed radially outward of the rotation conversion member in the outer space.
  6. 6. Hammer drill according to claim 1 or 2, characterized in that, The front housing is made of metal.
  7. 7. Hammer drill according to claim 1 or 2, characterized in that, A joint face seal member is provided on a joint face of the front case and the rear case.
  8. 8. Hammer drill according to claim 1 or 2, characterized in that, The drive mechanism includes two intermediate shafts parallel to the axial direction of the tool holder, one of the intermediate shafts transmitting rotation of the output shaft to the tool holder, and the other intermediate shaft converting the rotation of the output shaft into a striking motion of the drill bit by the rotation conversion member.
  9. 9. Hammer drill according to claim 1 or 2, characterized in that, A heat sink is formed on an outer surface of the front case.
  10. 10. Hammer drill according to claim 1 or 2, characterized in that, The motor is provided such that the output shaft is disposed in a posture extending along an axial direction of the tool holder, a fan is provided on the output shaft, an intake port is provided on either front or rear side of the housing, an exhaust port is provided on the other side, and the intake port and the exhaust port face each other across the axial direction of the output shaft.
  11. 11. Hammer drill according to claim 1 or 2, characterized in that, The front housing is formed longer than the rear housing in the axial direction of the tool holder.
  12. 12. Hammer drill according to claim 1 or 2, characterized in that, The 1 st bearing is a bearing bush.
  13. 13. Hammer drill according to claim 1 or 2, characterized in that, The 2 nd bearing is a ball bearing.
  14. 14. Hammer drill according to claim 1 or 2, characterized in that, The housing has an outer housing and a motor housing on a front side, the outer housing, the motor housing, and the inner housing being connected together in an axial direction of the tool holder, wherein the motor housing is assembled on a rear side of the outer housing for accommodating the motor, and A screw boss for screw-fastening the outer case and the motor case is formed to protrude toward the other side on either one of the outer case and the motor case, The inner housing is positioned by being engaged with the threaded boss.
  15. 15. The hammer drill according to claim 14, wherein, The inner housing is clamped by the outer housing and the motor housing.
  16. 16. The hammer drill according to claim 15, wherein, The inner housing is pushed from both front and rear sides by the outer housing and the motor housing.

Description

Hammer drill Technical Field The present invention relates to a hammer drill. Background The hammer drill rotatably holds a cylindrical tool holder to which a drill bit (bit) can be attached at a tip thereof in a housing. The tool holder includes a reciprocating piston (including a piston cylinder) and a ram that reciprocates in conjunction with the piston by an air spring. A drive mechanism is formed within the housing, the drive mechanism including a tool holder, a piston, and a ram, and being capable of imparting a rotational and/or impact motion to the drill bit. As disclosed in patent document 1, the drive mechanism is provided with an intermediate shaft parallel to the tool holder. The intermediate shaft has a flange sleeve as a rotation conversion member that transmits rotation of an output shaft of the motor to the tool holder and converts the rotation of the output shaft into reciprocating motion of the piston. The flange sleeve includes an arm which swings back and forth through a swash plate bearing (swash bearing) whose axis is obliquely fitted, and the arm is connected to the piston, so that the piston reciprocates through the swing of the arm. An inner housing for supporting the drive mechanism is provided in the housing. The inner housing has a front plate portion supporting a rear portion of the tool holder through a bearing, a rear plate portion supporting the output shaft through a bearing, and a connecting portion for connecting the front plate portion and the rear plate portion. [ Prior Art literature ] [ Patent literature ] Patent document 1 Japanese patent laid-open publication No. 2020-104238 Disclosure of Invention [ Problem to be solved by the invention ] In the hammer drill of patent document 1, a seal member is interposed between an outer periphery of a rear plate portion of an inner casing having a large radial dimension and an inner periphery of a rear portion of the casing. By this sealing member, a region (driving mechanism accommodating region) for accommodating the driving mechanism is formed in the front side of the rear plate portion and in the housing. Therefore, the size of the driving mechanism housing area and the housing becomes large. In the hammer drill of patent document 1, a fan for cooling the motor is provided on the output shaft behind the rear plate portion. But the air cooled by the motor is discharged from the radially outer side of the fan to the outside of the casing at the rear of the rear plate portion. Therefore, the cooling effect of the driving mechanism is insufficient. Accordingly, an object of the present invention is to provide a hammer drill which can achieve a compact structure even when the inner casing is partitioned to form a driving mechanism housing area, and which can also achieve an appropriate cooling effect of the driving mechanism. [ Solution for solving the problems ] In order to achieve the above object, the present invention is characterized in that a motor, a cylindrical tool holder, a driving mechanism, a rotation conversion member, and an inner housing are provided in a housing, The tool holder is used for mounting a drill bit on the top end and can rotate; the driving mechanism can perform a rotation action of the tool holder and/or a percussion action of the drill bit; The rotation conversion member is provided to the driving mechanism and is capable of converting rotation of an output shaft of the motor into a striking motion of the drill; The inner housing supports the drive mechanism and the tool holder via a 1 st bearing, the output shaft via a2 nd bearing, The inner housing is divided into a front housing for holding the 1 st bearing and a rear housing formed separately from the front housing for holding the 2 nd bearing and is formed by connecting the front housing and the rear housing in an axial direction of the tool holder, A sealing member for sealing an outer space of the inner case within the case is provided on the front case. [ Effect of the invention ] According to the present invention, since the inner housing is divided into the front and rear portions and the seal member is provided on the front housing, the inner housing having the reduced drive mechanism accommodation area can be formed on the rear side of the seal member. Therefore, the compactness of the product size is also facilitated. In addition, since the cooling air of the motor can be guided to the outside of the inner case, an appropriate cooling effect of the driving mechanism can be obtained. Drawings Fig. 1 is a perspective view of the hammer drill as seen from the rear. Fig. 2 is a central longitudinal section of the hammer drill. Fig. 3 is an enlarged view of a portion of the drive mechanism in fig. 2. Fig. 4 is a cross-sectional view A-A of fig. 3. Fig. 5 is an exploded perspective view of the outer housing, motor housing and inner housing. Fig. 6 is an exploded perspective view of the inner housing. Fig. 7 is a B-B cross-sectional view of fi