RU240269U1 - The connection unit of the adapter plate for installing the processing device and each of the legs for installing it on the workpiece of the mobile boring complex - Google Patents

Abstract

The utility model relates to mechanical engineering and can be used for machining holes in housing structures using mobile boring machines. The connection unit between the adapter plate for mounting the machining device and each of the legs for mounting it on the workpiece of the mobile boring machine comprises openings in the mating sections of the plate and the leg, in which a screw is installed for attaching the leg to form two flat friction connections. A groove is formed in the mating section of the leg, the side and rear walls of which enclose the mating section of the adapter plate with the screw located therein. A recess is formed on the rear wall of the groove, and annular grooves are formed on the side walls of the groove. Use of the utility model improves the reliability of fastening the adapter plate to the workpiece. 2 fig.

Description

This utility model relates to general and specialized mechanical engineering and can be used in all areas of industrial production for machining holes in hull structures using mobile boring machines. Areas of application: mechanical engineering industries producing large-scale, critical metal structures, such as spaceport launch pads, ships and vessels, and energy facilities. Potential users: heavy engineering companies.

Mobile boring complexes are known, designed for precise boring of holes in large-sized structures, for example, mobile boring complexes Climax [1], which are taken as a prototype.

A mounting kit is widely used to install and secure these mobile boring machines to the workpiece. It includes an adapter plate, onto which the mobile boring machine's power drive is mounted, and rotating supports consisting of legs with posts that are secured to the adapter plate with screws. After the rotating supports are installed on the workpiece, they are secured against rotation under operating forces by tightening the mounting screws. The secure locking of the legs relative to the support plate is ensured by frictional forces generated on the friction surfaces in the flat friction unit connecting them to the adapter plate.

The disadvantage of the described solution is the following.

Experience with mobile boring machines has shown that this mounting method does not provide sufficiently secure clamping of the arm relative to the adapter plate. When boring large-diameter holes, especially in difficult-to-machine materials, uncontrolled rotation of the arms relative to the adapter plate around the screw axis sometimes occurs. This leads to a disruption of the position of the boring machine achieved during its installation on the workpiece.

The objective and technical result of the utility model consist in increasing the service life of the connection unit of the rotary supports of a mobile boring complex by increasing the number of pairs of friction surfaces in the connection of the paw with the adapter plate, which ensures a corresponding increase in the moment of friction forces of the connection "paw-adapter plate", preventing uncontrolled rotation of the paw relative to the adapter plate under the action of working forces of processing.

The technical result of the utility model is achieved by the foot being designed with a groove whose walls encircle the adapter plate, increasing the number of pairs of friction surfaces to two. The rear wall of the groove is recessed, increasing the wall's compliance and ensuring tight contact between the mating friction surfaces when tightening the screw. Furthermore, the side surfaces of the groove are provided with annular grooves, increasing the average diameter of frictional force application and, consequently, the frictional moment at the interface between the foot and the adapter plate.

Fig. 1 shows a sketch of the device;

Fig. 2 - 3D model of the installation equipment kit.

The main view in Fig. 1 shows the adapter plate 1, to which four legs 2 are attached by screws. Each leg 2 is provided with a groove, the side walls 3 of which enclose the mating section of the adapter plate 1. On the rear wall 4 of the groove, a recess 5 is provided, which increases the flexibility of the groove and ensures reliable contact of its walls with the mating surfaces of the adapter plate 1. On the side walls 3 of the groove, annular grooves 6 are made, increasing the average diameter of the application of frictional forces and, accordingly, the frictional moment at the junction of the leg with the adapter plate. The other ends of the legs 2 are connected by a screw connection to the posts 7.

In Fig. 1 the cutting force moment M _res is indicated, as well as the opposing moments of friction forces M _mp at the connection points of the adapter plate 1 with the legs 2 and the support reactions R _on at the connection points of the legs 2 with the racks 7.

Section B-B shows the connection between the foot and the adapter plate, and indicates the screw thread diameter d _B and the recess diameter D _ob . View I indicates the foot width B _l and the average diameter of the friction force application D _mср of the connection between the foot and the plate.

Unlike the prototype, in which the connection between the foot and the plate is achieved by a frictional connection with a single pair of friction surfaces, in the claimed utility model it is implemented with two pairs of friction surfaces 3 (Figs. 1, 2). This doubles the friction torque between the plate and foot, respectively, with the same screw tightening force. Furthermore, annular grooves 6 (Figs. 1, 2) are made on the friction surfaces around the screw holes, increasing the friction torque by increasing the average diameter of the frictional force application with the same screw tightening force as in the prototype.

For example, the Climax ВВ5000 mobile boring machine, chosen as a prototype, uses a mounting kit that includes stands welded to the workpiece and screwed to the legs. The legs, in turn, are attached to the intermediate plate with a single-pair (z=1) flat friction joint using a screw.

As an example, let's calculate the required friction torque and tightening force for the screws securing the legs to the adapter plate. For this, we'll use the methodology described in [2] and illustrated by the calculation diagram (Fig. 1).

The moment of cutting forces relative to the axis of the boring bar when boring a hole, created by the drive of the boring complex

,

Where - main cutting force;

- diameter of the bored hole,

is transmitted to the transition plate and is balanced by the tangential reactions of the legs:

Where - diameter of the paw axes;

- number of paws.

The minimum required (without taking into account safety factors) moment of friction forces between the surfaces of the paw and the adapter plate

Where - paw reach (distance between the axes of the paw attachment to the adapter plate and the rack).

Minimum required screw tightening force (ensuring the required friction torque)

Where - the average diameter of the friction forces on the annular friction surface between the adapter plate and the paw with an outer diameter equal to B _l - the width of the paw, and an inner diameter equal to - the diameter of the undercut (or, in the absence of an annular groove, equal to the diameter of the hole for the screw - ); - coefficient of friction between the adapter plate and the paw; - the number of pairs of friction surfaces.

Required screw tightening torque (according to RD 37.001.131-89);

,

Where - screw thread pitch;

- total coefficient of friction (without coating and lubrication);

- average diameter of screw thread;

- screw head diameter;

- diameter of the screw hole.

Let us consider boring a hole in a ship hull structure made of steel using a Climax ВВ5000 mobile boring complex with a unit specific cutting force of the material Kc = 2500 N/mm ² , and a chip thickness index m _C = 0.24, with a feed per revolution of the tool S _O , that is, a chip thickness a = 0.25 mm, cutting depth t = 5 mm, and a specific cutting force per chip cross-section

Kc* = Kc⋅(a) ^-m c = 2500⋅(0.25) ^-0.24 = 3487 N/mm ² ;

= Кс*⋅t⋅ S _О = 3487⋅5⋅0.25 = 4358.75 N.

On the processing diameter - this corresponds to the working force (torque) of processing

.

Taking, as in the prototype, And , we will get the reactions of the paws

,

and the minimum required moment of frictional forces between the surfaces of the paw and the adapter plate

accordingly, the minimum required screw tightening force (with a friction coefficient

, ,

- screw M16 pitch 2 mm):

- for a prototype with one pair of friction surfaces (z=1), without an annular groove ;

accordingly, the required tightening torque of the screw

(at , , ):

- for a prototype with one pair of friction surfaces (z=1), without an annular groove ;

For the considered operating conditions of the boring complex on the workpiece, it is difficult to provide the required tightening torque for the screw in the prototype design: the tightening force on the key with a 0.3 m lever will be approximately 500 N.

For the utility model, the minimum required screw tightening force (with a friction coefficient of

, , - screw M16 pitch 2 mm):

- with two pairs of friction surfaces , with annular groove ;

accordingly, the required tightening torques of the screw (at , , ):

- with two pairs of friction surfaces ), with annular groove .

This utility model significantly increases the friction torque between the foot and the adapter plate, in this example by 2.4 times, while maintaining the same screw tightening torque. This significantly improves the reliability of the mobile boring machine's installation on the workpiece. This is especially important for machining difficult-to-machine materials, under unstable cutting conditions with high and highly dynamic loads.

Bibliography:

1. https://www.climaxportable.com/.

2. Ledeneva N.F. Mechanics. Machine parts: textbook, manual / N.F. Ledeneva.- Ulyanovsk: UVAU GA. 2005. - 128 p.

Claims (1)

A connection unit for an adapter plate for mounting a processing device and each of the legs for mounting it on a workpiece of a mobile boring complex, comprising holes made in the mating sections of the plate and the leg, in which a screw is installed for attaching the leg with the formation of two flat friction connections, characterized in that a groove is made in the mating section of the leg, the side and rear walls of which cover the mating section of the adapter plate with a screw located therein, wherein a depression is made on the rear wall of the groove, and annular grooves are made on the side walls of the groove.