Impact tool

1. A method for assembling an impact tool, comprising:

providing a housing body housing a motor;

housing a rotatable spindle and an impact mechanism operable to convert the rotation of the spindle into intermittent impact actions in a first direction which is a circumferential direction of the spindle, in a hammer casing having an opened rear end and being independent from the housing body;

closing the opened rear end of the hammer casing with a rear cover so as to rotatably support the spindle, thereby forming a front unit;

coupling the front unit with the housing body by engaging a first engagement member formed on an outer circumferential face of the rear cover and a second engagement member formed on an inner face of the housing body and engaging with the first engagement member, so that a movement of the front unit relative to the housing body in a second direction parallel to a rotation axis of the spindle is restricted, and inserting an output axis of the motor into a through hole formed in the rear cover, thereby coupling the output axis of the motor with the spindle.

2. The method as set forth in claim 1 , further comprising:

engaging a third engagement member formed on an outer face hammer casing and a forth engagement member, formed on an inner face housing body and engaging with the third engagement member, so that a movement of the front unit in the first direction is restricted.

3. An impact tool, comprising:

a hammer casing, housing a rotatable spindle and an impact mechanism operable to convert the rotation of the spindle into intermittent impact actions in a first direction which is a circumferential direction of the spindle, and having an opened rear end;

a rear cover, coupled to the hammer casing and closing the opened rear end so as to rotatably support the spindle, the rear cover having a through hole;

a motor, having an output axis extending through the through hole and coupled with the spindle to transmit a rotation of the motor to rotate the spindle;

a housing body, housing the motor, being independent from the hammer casing and coupled to a rear side of the rear cover;

a first engagement member, formed on an outer circumferential face of the rear cover; and

a second engagement member, formed on an inner face of the housing body and engaging with the first engagement member so as to restrict a movement of the rear cover relative to the housing body in a second direction parallel to a rotation axis of the spindle.

4. The impact tool as set forth in claim 3 , wherein the first engagement member is a flange which is monolithically formed with the rear cover, and the second engagement member is a groove receiving the flange.

5. The impact tool as set forth in claim 4 , wherein the flange has a polygonal cross section in a third direction perpendicular to the second direction.

6. The impact tool as set forth in claim 4 , wherein the flange is concentric with the through hole.

7. The impact tool as set forth in claim 3 , further comprising:

a third engagement member, formed on an outer face of the hammer casing; and

a fourth engagement member, formed on an inner face of the housing body and engaging with the third engagement member so as to restrict a movement of the hammer casing in the first direction.

8. The impact tool as set forth in claim 7 , wherein the third engagement member is a first rib projected from the outer face of the hammer casing, and the fourth engagement member is a second rib coming into contact with the first rib in the first direction.

9. The impact tool as set forth in claim 7 , wherein:

the outer face of the hammer casing includes a first curved face and a first flat face which serves as the third engagement member; and

the inner face of the housing body includes a second curved face and a second flat face which comes in contact with the first flat face to serve as the fourth engagement member.

10. The impact tool as set forth in claim 9 , wherein:

a projection is formed on one of the first flat face and the second flat face; and

a recess receiving the projection is formed on the other one of the first flat face and the second flat face.