RU2288831C1 - Small-diameter holes drifting apparatus - Google Patents

Abstract

FIELD: mechanical working of openings, possibly in precise machine engineering and instrument making.

SUBSTANCE: apparatus includes housing with slit whose lower plane is designed for placing part and punch mounted by interference fit in guiding sleeve and having drive with pusher. Guiding sleeve is in the form of clamp including slit boss whose portions are joined through elastic spokes with rim. Clamp is fixed on plate arranged in slit of housing over part. Plate is mounted with possibility of rotation relative to housing in plane normal relative to axis of clamp.

EFFECT: enhanced operational reliability, simplified maintenance of apparatus.

2 dwg

Description

The invention relates to the field of machining of holes, and in particular to devices for mandrel drilling of small diameter holes, and can find application in precision engineering and instrumentation.

A device is known for mandreling holes, comprising a housing with a support for installing the workpiece, a mandrel and a pusher drive mandrel [Gorokhov V.A. Processing of parts by plastic deformation. - Kiev: Technique, 1978, p.106].

However, when burning holes of small diameter (less than 3 mm), the use of the known device is difficult. When entering the hole, the mandrel can be skewed about its axis, which leads to a decrease in the accuracy of the machined hole and can also cause the mandrel to break.

A device is known [A.S. USSR No. 1087315, class B 24 V 39/02, 1984, Bull. No. 15], designed to burn small-diameter holes, comprising a housing with a slot for installing the workpiece, mandrels located between the pushers, a spring-loaded mandrel lock located in the upper part of the housing, and a bypass cracker for pushing the machined part, and an opening is made in the cracker, designed to guide the mandrels when they are returned to the upper part of the housing.

Since in the known device the mandrels are installed in the housing with a gap, then during the course of the hole to be machined they can be skewed and broken. In addition, the presence of a spring-loaded clamp mandrels complicates the design of the device.

A device is known for mandreling holes of small diameter [Certificate on PM No. 10134, class. B 24 V 39/02, 1999, Bull. No. 6], selected as a prototype, comprising a housing with a slot for installing the workpiece, a mandrel and a drive pusher located in an opening of a sleeve fixed in the housing of the sleeve made of elastic antifriction material, the mandrel being installed in the sleeve of the interference fit.

A disadvantage of the known device, which manifests itself during operation, is the inevitable reduction in interference between the mandrel and the bore of the sleeve due to the creep of its material. This leads to the need for frequent replacement of the sleeve with a new one. Another disadvantage of the known device is the difficulty of installing the mandrel in the sleeve, which is carried out from below. Moreover, with a decrease in the height of the workpiece, installing the mandrel in the sleeve becomes more and more difficult.

The objective of the invention is to increase the reliability of the device and the convenience of its maintenance.

The solution of these problems is provided as follows.

The device comprises a housing with a slot, the lower plane of which serves to install the part. The interference mandrel is placed in a collet, which is rigidly fixed to a plate mounted in the upper part of the housing slot (above the part) with the possibility of rotation relative to it in a plane perpendicular to the collet axis. The latter is made in the form of a split hub, parts of which are connected by elastic spokes with a rim. An opening is made coaxially with the collet in the upper part of the housing, in which the mandrel drive pusher is placed with a gap. In the lower part of the housing there is a hole for the mandrel.

The essence of the proposed device is clarified by the drawings, where Fig. 1 shows its general view, and Fig. 2 is a section along AA in Fig. 1.

The device consists of a housing 1, a mandrel 2 and a pusher 3 of its drive. In the housing 1, a slot is made, the lower plane of which serves to install the workpiece 4. The mandrel 2 is installed with an interference fit in the collet 5, made in the form of a split hub, part A of which is connected by elastic spokes B to the rim B (figure 2). The collet 5 is pressed into the hole of the plate 6, which is mounted in the upper part of the slot in the housing 1 on the axis 7, rigidly fixed with a nut 8 on this housing. In the upper part of the housing 1 there is an opening for placement (with a gap) of the pusher 3 fixed in the rod 9 of its drive by a screw 10. In the lower part of the housing 1 there is a hole for the mandrel 2. To support the plate 6, there is a plate 11, screwed 12 to the housing 1. To ensure coaxiality of the hole for the pusher 3 and the hole in the collet 5, a ball retainer of the plate 6 is provided, consisting of a conical hole Г in this plate, the housing 13, screwed to the housing 1 with screws 14, the ball 15, the spring 16 and the screw 17. To rotate plate has a handle 18 (FIG. 2) screwed into this plate. To limit the angle of rotation of the plate 6 is a pin 19, pressed into the plate 11.

The device operates as follows.

The workpiece 4 is installed on the lower plane of the slot in the housing 1 coaxially with the mandrel 2. The drive is turned on, its rod 9 with the pusher 3 moves down. In this case, the mandrel 2 is pushed out of the collet 5, enters the workpiece hole 4, pushed through it and falls into the hole in the housing 1. Then the rod 9 with the pusher 3 rises and takes its initial position. The machined part 4 is removed from the housing 1. Next, using the handle 18, the plate 6 with the collet 5 is rotated on the axis 7 until it stops in the pin 19 and is thus removed from the slot in the housing 1. The mandrel 2 is mounted on top of the collet 5. After that, the plate 6 s collet 5 using the handle 18 is returned to its original position. In this case, the ball 15 under the action of the spring 16 enters the conical hole G in the plate 6 and thereby fixes its position. Next, install part 4 and the burning cycle is repeated.

Thus, due to the use of a collet with a high durability for guiding the mandrel, the reliability of the proposed device is increased in comparison with the known one, and by placing the collet on a turntable, the serviceability is improved.

On the basis of the proposed device, a device for a pneumatic press was developed to ^{burn a} hole with a diameter of 1.3 ^{+ 0.02} mm in a sleeve of steel 45 with a height of 10 mm. The tests performed indicate the high reliability of the device in operation, as well as the convenience of its maintenance.

Claims (1)

A device for mandrel drilling of small diameters, comprising a housing with a slot, the lower plane of which is intended for mounting the part, a mandrel placed with an interference fit in the guide sleeve, and a mandrel drive with a pusher, characterized in that the guide sleeve is made in the form of a collet, which is a split hub , the parts of which are connected by elastic spokes with the rim, the collet being fixedly mounted on the plate mounted in the slot of the housing above the installed part with the possibility of rotation relative to it in the plane, erpendikulyarnoy axis of the collet.

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