CS253357B1 - Combined tool for precision holes - Google Patents

Abstract

Combined tool for making precise holes, especially cylinders of linear hydraulic motors. The purpose of the solution is to increase the operational reliability and performance of the tool, especially when machining higher strength. The machine consists of a drilling rod, a machining part with at least one roughing knife and one finishing knife and a forming part. The essence of the solution is that a safety roughing knife is assigned to the roughing knife radially and axially offset and a safety finishing knife is assigned to the finishing knife. The edge of the roughing knife is located in a plane rotated by 180° and the edge of the safety roughing knife in a plane rotated by 90° relative to the plane in which the edge of the finishing knife is located. The edge of the safety finishing knife is located in a plane rotated by 90° in front of the plane of the edge of the roughing knife.

Description

BACKGROUND OF THE INVENTION The present invention relates to a combination tool for producing precision bores, in particular cylinders of linear hydraulic motors.

Often, a process consisting of roughing a hole with one tool and completing the hole with a second tool, which may be, for example, a tool according to U.S. Patent No. 126,618, consists of a knife head and a forming part with rotary forging bodies. This tool has proven itself in the manufacture of precision holes up to 120 mm in diameter. For larger diameters, it has proven more advantageous to construct the tool according to the Czechoslovak author's certificate No. 210 770. Its knife part is formed from a body attached to the front side of the tool holder and provided with at least one reaming knife carrier. The forming part is provided with a cam attached to a holder, on the circumference of which the replaceable inserts are arranged. The outer surface of the cam is in alternating contact with the molding bodies between which guide rails are attached. The tool described may also be provided with at least two roughing knives in order to make a precise hole in a single operation in which roughing, reaming and finishing are performed simultaneously with a single tool. A certain disadvantage of this tool is the difficulty of obtaining a frangible chip during machining, which is crucial for the perfect chip removal from the cutting point. This is due to the unequal cutting depth of the roughing and reaming knives and their different geometries. The optimum cutting conditions for roughing and reaming are quite different and it is difficult to determine compromise feedrate and cutting speeds.

The above-mentioned disadvantages of the known tools are largely eliminated by a combination tool consisting of a drill rod, a machining part with at least one roughing knife and a finishing knife and a forming part according to the invention. The essence of the invention

- 2 253 357 is that the roughing knife is assigned to the roughing knife radially and axially offset, the finishing knife is assigned to the finishing knife radially and axially offset ·

The rake knife blade is positioned in a plane rotated 180 ° and the rake blade safety blade in a plane rotated 90 ° relative to the plane in which the blade of the finishing knife is located. The cutting edge of the safety finishing knife is positioned in a plane rotated 90 ° in front of the plane of the rake knife.

The main advantage of the combination tool according to the invention is higher operational reliability, especially when machining semi-finished products of higher strength steels. If the riving knife insert is destroyed, d, o engages the safety roughing knife · Similarly, in case of breakage of the finishing knife insert, the safety finishing knife enters into engagement · The failure is indicated acoustically or by ammeter · This reduces the possibility of damage tools and workpiece deterioration · The channel system ensures perfect chip flushing to achieve this effect. Compared to the usual process, the time required to make the hole is significantly reduced.

An exemplary embodiment of a combination tool according to the invention is shown in simplified form in the accompanying drawings.

In FIG. 1, the tool is in a front view, partially in section, in a plane extending along its longitudinal axis.

Fig. 2 is a side view of the tool; and Fig. 5 is a schematic of a knife alignment view perpendicular to the tool axis. The combination tool according to the invention consists of a drill rod 1 to which the machining part 2 and the forming part are attached. The machining part 2 consists of a body 20 to which a carrier 21 is mounted in which the holder 22 of the finishing knife 25 is movably mounted. Adjustable in a known manner by means of a spacer wedge 25, the carrier 21 furthermore holds the holder 22 of the safety finishing knife 24 and the inserts 26 with the roughing knife 22 and the safety roughing knife 28. are mounted. JN 150412, completed with chipbreaker 29.

253 357

The body 20 is further provided with a cone 200 for clamping onto the drill rod 1 and a plurality of channels 201, 202, 20 > 204 for distributing cutting fluid for flushing chips. The forming part 6 is of a generally known embodiment and consists of a cage 30 rotatably supported by bearings 31 on the body 20. Its cam 32 is fixedly fixed to the body 20 and can be provided with replaceable parts 32Q. In the cage 30, molding bodies 33 and guide rails 34 are also mounted.

Claims (2)

SUBJECT OF THE INVENTION Combination tool for making precision holes, consisting of a drill rod, a machining part with at least one roughing and at least one finishing knife and a forming part, characterized in that a roughing knife (28) is assigned to the roughing knife (27) radially and axially offset. , a safety finishing knife (24) is associated with the finishing knife (23) radially and axially offset, wherein the edge of the rake knife (27) is located in a plane rotated 180 ° and the edge of the rake knife (28) is placed in a plane rotated by 90 ° to the plane in which the blade of the finishing knife (23) and the blade of the safety finishing knife (24) are located in a plane rotated 90 ° in front of the plane of the knife of the rake knife (27) « 2 drawings 253 357 29 27 204 CM Giant.