FORM 2
THE PATENT ACT 1970 (39 of 1970)
&
The Patents Rules, 2003 COMPLETE SPECIFICATION (See Section 10, and rule 13)
1. TITLE OF INVENTION
BROACH CHIP REMOVAL APPARATUS AND BROACH CHIP REMOVAL METHOD
2. APPLICANT(S)
a) Name : MITSUBISHI HEAVY INDUSTRIES, LTD.
b) Nationality -. JAPANESE Company
c) Address : 16-5, KONAN 2-CHOME,
MINATO-KU, TOKYO 1088215, JAPAN
3. PREAMBLE TO THE DESCRIPTION.
The following specification particularly describes the invention and the manner in which it is to be performed : -

TECHNICAL FIELD
The present invention relates to a broach chip removal apparatus and a broach chip removal method which are capable of removing chips attached to the inside of cutting grooves of a broach.
BACKGROUND ART
Broaching has heretofore been known as a method of machining a groove in a predetermined shape on an inner peripheral surface or on a surface of a workpiece in an axial direction thereof at high accuracy and high efficiency. In this broaching, a shaft-shaped tool called a broach, which has numerous cutting edges having sizes gradually increased from a front end side to a rear end side, is either pulled or pushed while being pressed against the inner peripheral surface or the surface of the workpiece. Hence the groove can be formed in conformity to the contour of the broach in a single pass.
Accordingly, the broach is configured to perform cutting on the workpiece and chips are therefore formed at the time of the cutting. Here, since the cutting edges of the broach are formed in multiple stages in an axial direction thereof, the chips in a curled state may be attached to the inside of cutting grooves (chip pockets) between the cutting edges right after the cutting. When the chips are attached to the inside of the cutting grooves as described above, it is not possible to form a precise groove in the next cutting. In addition, the cutting edges (the cutting grooves) and a machined surface of the workpiece may be damaged or burrs may be formed on the workpiece.
Thus chip removal apparatuses have heretofore been provided that are configured to rub a broach with a brush and to remove chips attached to the inside of cutting grooves thereof. Such a conventional chip removal apparatus is disclosed in Patent Document 1, for example.

PRIOR ART DOCUMENT PATENT DOCUMENT
Patent Document 1: Japanese Utility Model Registration Application Publication No. Sho 63-124420
SUMMARY OF THE INVENTION
PROBLEM TO BE SOLVED BY THE INVENTION
The above-described conventional chip removal apparatus is configured to remove chips attached to the inside of cutting grooves by rotating a brush implanted on an outer peripheral surface of a main body and moving a broach in an axial direction thereof in a state where the brush is pressed against an outer peripheral portion of the broach.
However, with such a configuration that the brush is simply pressed against the outer peripheral portion of the broach as in the conventional apparatus, the brush repeatedly performs actions to go over the cutting edges and to go into the cutting grooves. Therefore, this brush may fail to reach bottoms of the cutting grooves. In the meantime, a local load is applied to the brush as the above-described actions of the brush are repeatedly performed. Hence, the load not only makes the brush likely to fall into a bent state but also makes the brush likely to wear out quicker. Accordingly, the chip removal performance of the conventional apparatus is degraded and the chips may be not removed completely.
The present invention therefore intends to solve the aforementioned problem and an object thereof is to provide a broach chip removal apparatus and a broach chip removal method, which are capable of efficiently removing chips attached to the inside of cutting grooves of a broach by inserting a brush into bottoms of the cutting grooves.

MEANS FOR SOLVING THE PROBLEM
The broach chip removal apparatus according to the present invention to solve the above-described problem is configured to remove a chip from a broach including cutting edges provided in multiple stages at a regular interval in an axial direction thereof, the broach chip removal apparatus characterized by comprising: broach moving means for moving the broach in the axial direction; a brush implanted in a screw-thread fashion at a lead equal to a pitch between the cutting edges and being meshable with cutting grooves formed between the cutting edges; brush rotating means for rotating about an axis of the brush; and controlling means for controlling the broach moving means and the brush rotating means so that the cutting grooves mesh with the brush.
The broach chip removal method according to the present invention to solve the above-described problem is a method of removing a chip from a broach including cutting edges provided in multiple stages at a regular interval in an axial direction thereof, the broach chip removal method characterized in that movement of the broach in the axial direction is synchronized with rotation of the brush about an axis so that cutting grooves formed between the cutting edges mesh with a brush implanted in a screw-thread fashion at a lead equal to a pitch between the cutting edges, whereby a chip attached to an inside of the cutting groove is removed.
EFFECTS OF THE INVENTION
Thus, according to the broach chip removal apparatus and the broach chip removal method of the present invention, the brush can be inserted into the cutting grooves down to the bottoms thereof by controlling the movement of the broach in the axial direction and the rotation of the brush about the axis of the brush so that the cutting grooves of the broach mesh with the brush. Thus the chips attached to the inside of the cutting grooves can be removed efficiently.

BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 Fig. 1 is a front view of a broach chip removal apparatus according to an embodiment of the present invention.
Fig. 2 Fig. 2 is a side view of the broach chip removal apparatus according to the embodiment of the present invention.
Fig. 3 Fig. 3 is a view showing an operation to remove chips on a broach using a rotary brush.
MODES FOR CARRYING OUT THE INVENTION
A broach chip removal apparatus and a broach chip removal method according to the present invention will be described below in detail by using the drawings.
EMBODIMENT
A chip removal apparatus shown in Fig. 1 and Fig. 2 is an apparatus configured to remove chips attached to a broach 11 after machining by use of a rotary brush 31.
The broach 11 is used for so-called internal broaching, which is cutting performed on a surface of an unillustrated workpiece to form a groove in a predetermined shape in an axial direction thereof. Numerous cutting edges 12 designed to increase height dimensions gradually from a front end side to a rear end side are provided at given pitch intervals on a side surface of this broach 11. In addition, cutting grooves (chip pockets) 13 are formed respectively between the cutting edges 12 (see Fig. 3).
Meanwhile, the broach 11 is fitted in a side portion of a holder 21 and a broach movement motor (broach moving means) 22 is connected to this holder 21 through a ball screw mechanism and the like. Accordingly, it is possible to move the broach 11 in such a manner that the broach 11 can advance or retreat in an axial direction thereof by driving the broach movement motor 22.

In the meantime, the rotary brush 31 is formed of a cylindrical or columnar main body 32 and a brush 33 implanted in a screw-thread fashion (helically) on an outer peripheral surface of this main body 32. This brush 33 is made of nylon having a certain level of rigidity and is arranged in the screw-thread fashion at a lead (an amount of advance in the axial direction per revolution) equal to the pitch between the cutting edges 12 (between the cutting grooves 13) on the broach 11.
Moreover, a brush rotation motor (brush rotating means) 41 is connected to one end surface of the main body 32 of the rotary brush 31. Accordingly, the rotary brush 31 can be rotated about an axis of the brush by driving the brush rotation motor 41.
In addition, an NC apparatus (controlling means) 51 to control the movement and the rotation is connected to the broach movement motor 22 and the brush rotation motor 41. Specifically, the NC apparatus 51 is configured to control the broach movement motor 22 and the brush rotation motor 41 and thereby to synchronize the movement (a movement speed) of the broach 11 in the axial direction with the rotation (a rotation speed) of the rotary brush 31 about the axis so that the cutting grooves 13 on the broach 11 can mesh with the brush 33 on the rotary brush 31.
Accordingly, in a case of removing chips from the broach 11, the broach 11 after the machining is first fixed to the holder 21 located in a predetermined retreat position. Subsequently, the holder 21 to which the broach 11 is fixed is moved to a predetermined position to start chip removal as shown in Fig. 1 and Fig. 2.
Then, the broach 11 is moved in the axial direction thereof by driving the broach movement motor 22. Moreover, the rotary brush 31 is rotated about the axis of the brush by driving the brush rotation motor 41. At this time, the movement of the broach 11 in the axial direction and the rotation of the rotary brush 31 about the axis are subjected to synchronization control by the NC apparatus 51 so that the cutting grooves 13 on the broach 11 can mesh the brush 33 on the rotary brush 31. In this way, the brush 33 is inserted into bottoms of the cutting grooves 13 as shown in

Fig. 3. Thus the chips attached to the inside of the cutting grooves 13 will be removed efficiently.
Subsequently, when the holder 21 to which the broach 11 is fixed is moved to a predetermined position to finish chip removal, all the chips attached to the inside of the cutting grooves 13 are removed. Hence a chip removal operation of the rotary brush 31 is completed.
Therefore/ according to the broach chip removal apparatus and the broach chip removal method according to the present invention, the brush 33 can be inserted into the cutting grooves 13 down to the bottoms thereof by performing the synchronization control of the movement of the broach 11 in the axial direction and the rotation of the rotary brush 31 about the axis using the NC apparatus 51 so that the cutting grooves 13 on the broach 11 can mesh with the brush 33 on the rotary brush 31. Thus the chips attached to the inside of the cutting grooves 13 can be removed efficiently.
Moreover, a local load on the brush 33 can be prevented because the brush 33 is directly inserted into only the cutting grooves 13 without going over the cutting edges 12. In this way, it is possible to prevent the brush 33 from falling into a significantly bent state or from wearing out and thereby to extend life of the brush. In addition, since the chips attached to the inside of the cutting grooves 13 can be reliably removed, it is possible not only to suppress damages on a surface of a workpiece but also to suppress damages on the cutting edges 12 and the cutting grooves 13 in the next machining. Hence, tool life can also be extended.
INDUSTRIAL APPLICABILITY
The present invention is applicable to a broach chip removal apparatus to direct chips that fall from a broach to a prescribed collection spot without scattering the chips.

WE CLAIM:
1. A broach chip removal apparatus configured to remove a chip from a broach
including cutting edges provided in multiple stages at a regular interval in an
axial direction thereof, the broach chip removal apparatus characterized by
comprising:
broach moving means for moving the broach in the axial direction;
a brush implanted in a screw-thread fashion at a lead equal to a pitch between
the cutting edges and being meshable with cutting grooves formed between
the cutting edges;
brush rotating means for rotating about an axis of the brush; and
controlling means for controlling the broach moving means and the brush
rotating means so that the cutting grooves mesh with the brush.
2. A broach chip removal method of removing a chip from a broach including
cutting edges provided in multiple stages at a regular interval in an axial
direction thereof, the broach chip removal method characterized in that
movement of the broach in the axial direction is synchronized with rotation of
the brush about an axis so that cutting grooves formed between the cutting
edges mesh with a brush implanted in a screw-thread fashion at a lead equal
to a pitch between the cutting edges, whereby a chip attached to an inside of
the cutting groove is removed.