JPH0422894Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a broach for machining grooves mainly for machining parts of machines such as electric machines and automobiles.

(Prior Art) In recent years, machining using broaches has been increasingly used for machining these grooves in terms of both machining efficiency and accuracy.
For example, in a workpiece W as shown in FIG. 6, a small hole h is drilled in advance, and a groove G leading from the outer periphery to the small hole h is machined with a milling cutter or a broach, while a hole H on the center side of the workpiece W is machined using a milling cutter or a broach. A groove G leading to the small hole h is machined with a broach.

A broach used for such processing, for example, as shown in FIG. 8, has a planar shape shown in A, and side shapes shown in B and C in the same figure. The broach 1 is composed of a blade part A having a large number of cutting edges 2, a rake face 3, a blade groove 4, etc. on both sides, and a body B that supports the blade part A. Furthermore, there are various shapes of the small hole h and the groove G of the workpiece W. In addition to what is shown in Figure 6, examples are shown in Figure 7 A, B, and C.
For example, the groove _G3 shown in FIG. 8C is machined using a broach as shown in FIG. 8C.

(Problems to be solved by this invention) The broach used for machining the groove G leading from the hole H side of the workpiece W to the small hole h shown in FIG. 6 is as shown in FIG. Since the broach is attached to the body and fixed with screws 6, it is desirable to make the body as large as possible in terms of the rigidity of the broach. However, considering the size of the hole in the workpiece and the strength of the broach holder, the size of the body B of the broach, especially the body height T, is limited and cannot be increased.

On the other hand, in manufacturing a broach, the cutting groove 4 and the rake face 3 are ground with a grindstone as shown in FIG. 10 and subsequent figures. For example, as shown in FIGS. 10 and 11, the broach is positioned by pressing the body B of the broach onto the positioning part 12 of the jig magnetic stand 11 placed on the table 10 of the grinding machine, and further using magnetic force. After fixing the body of the broach, grinding is performed by rotating the grindstone 13 located above the broach and moving the table 10 in the direction of the arrow in FIG. In addition, as the broach is used, the cutting edge 2 becomes dull, so as shown in Figure 10, the rake face 3 is often reground to restore the sharp cutting edge and process a large number of workpieces. making it possible to do so.

In addition, the body part B is small, especially the body height T
If the broach is small, the magnetic fixing force to support the grinding force applied to the blade part A is insufficient, making stable grinding impossible.Furthermore, if the broach material is non-magnetic, such as cemented carbide, Grinding is impossible with this method.

Furthermore, when grinding the blade groove 4 and rake face 3 of a broach that are insufficiently or impossible to fix magnetically, it is unavoidable to hold down the body B of the broach 1 with a bolt 16 to hold down the body B of the broach 1, as shown in Figs. It was tightened to jig 11 and ground. However, with this method, Figure 12,
As can be seen from FIG. 13, the blade groove portion 4 is covered by the presser metal 15 because the grindstone 13 interferes with the presser metal 15.
Since it was not possible to grind grooves a and 4b, after grinding grooves other than these grooves, the grinding was temporarily stopped, the broach was shifted and reattached to a position where the blade grooves 4a and 4b could be ground, and then grinding was continued. However, this method has the problem that not only is the grinding work complicated, but it is also difficult to grind the distance from one cutting edge to the next cutting edge, that is, the pitch, with good accuracy.

(Means for solving the problem) This invention was made to solve the above-mentioned problem, and is a broach in which a cutting edge for grooving is provided on both sides in the longitudinal direction of the blade. The broach can be easily attached to the grinding jig by providing an engagement portion with the grinding jig.

(Embodiment and operation) Next, an embodiment of this invention will be explained with reference to the drawings. As shown in FIG.
A convex strip 17 of the shape
The broach 1 was fixed by being press-fitted from the rear end into a V-shaped concave portion 18 provided in the broach using a screw 19. In addition to the V-shaped convex shape mentioned above, the broach tip has a V-shaped concave shape 17a shown in FIG.
Concave shape 17b, convex arc shape 17c, D2
It can be made into an appropriate shape such as a shape 17d that is a combination of two circular arcs R. Examples of the jig and the mounting state are shown in FIGS. 3 and 4.

(Effects) As mentioned above, this invention uses a broach that has cutting edges for grooving on both sides in the longitudinal direction, and has a part that engages with the grinding jig at the tip, making it extremely easy to attach the broach to the jig. Not only that, but the broach can be stably set on the jig without the trouble of shifting the broach and installing it in order to avoid the position of the presser metal on the jig. Moreover, there is no restriction on the size of the body B of the broach, especially the height of the body. Furthermore, since there is no need to use magnetic force in the jig, the structure of the jig can be simplified, and many other excellent effects can be achieved.

[Brief explanation of the drawing]

Figure 1A is a front view of an embodiment of this invention, Figure 2B is a side view, Figure 2 is a schematic diagram of the broach in Figure 1 attached to a jig, and Figure 3 is a diagram of another embodiment. A schematic diagram of a broach attached to a jig, FIG. 4 is a schematic diagram of another embodiment of a broach attached to a jig, and FIGS. FIG. 6 is a front view of an example of the shape of the workpiece according to this invention, and FIG. 7 is a side view of various shapes of the workpiece.
Figures A to C are schematic diagrams of the groove shape of the workpiece, Figure 8 A is a front view of the conventional product, B and C are side views, Figure 9 is a sectional view showing an example of the conventional product, and Figure 10 is FIG. 11 is a schematic side view of FIG. 10, FIG. 12 is a schematic diagram of the clamped state of the conventional product, and FIG. 13 is a front view of the conventional product shown in the clamped state. be. 3... rake face, 4... cutting edge, 11... jig,
17...Engaging portion, 17a, 17b, 17c, 17
d...Engagement part.

Claims (1)

[Claims for Utility Model Registration] (1) A broach having cutting edges for grooving on both sides in the longitudinal direction, characterized in that the tip is provided with a portion for engagement with a grinding jig. (2) The broach according to claim 1, wherein the engaging portion has a concave shape. (3) The broach according to claim 1, wherein the engaging portion has a convex shape.