RU2602574C1 - Device for globoid worms cutting at cnc machine - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: device includes plate, on which device rotary part is mounted in form of gear sector, having possibility of turning along guides about vertical axis by means of rotation mechanism. Rotary mechanism is made in form of toothed rack, rigidly connected with ball-screw pair screw, rotating from step motor by CNC signals. Cutter is fixed on transverse support so, that during sector rotation it communicates with circular movement, wherein cutter performs circular motion around the sector axis of at a distance from worm axis, equal to actual engagement axis. Rotating ball-screw pair nut casing of gear sector drive and nut drive motor are placed on support plate.

EFFECT: higher performances and processing efficiency.

1 cl, 8 dwg

Description

The invention relates to the field of material processing by cutting, and in particular to the technology of manufacturing worm gears, and is intended for cutting globoid worms.

A device is known for cutting globoid worms on a lathe, including a housing on which a rotary part with a cutting tool is mounted, a drive that contains a pinion gear designed to be mounted on the machine spindle, a spurious gear wheel and a driven gear mounted on the shaft of the worm, forks, mounted on the spindle of the machine and on the shaft of the worm and interconnected by a finger on which is mentioned the spurious gear wheel, while the rotary part is made with the possibility of of rotation around its axis (patent RU №2101139, 6 IPC B23B 5/48, publ. 10.01.1998).

The disadvantage of this device with a removable wheels guitar is the inability to configure the cutting of globoid worms at any step, in addition, this device has low technological capabilities and processing performance.

Closest to the claimed invention is a device for a lathe for cutting globoidal worms, containing a plate on which a rotary part of the device is mounted in the form of a sector, having the ability to rotate along the guides around the vertical axis using a rotating mechanism, while informing the circular movement of the cutter mounted on cross support (Samoilov S.N. et al. Technology of heavy engineering. - M .: Mashgiz, 1962, p. 399 and 199).

Cutting the worm with a cutter gives low productivity and is associated with high manual labor costs for the machinist, because machining is performed with a significant number of tool passes. All this is a disadvantage of the known device. In addition, only roughing can be performed on this fixture.

The technical problem to which the claimed invention is directed is to increase the technological capabilities and processing productivity.

This problem is solved in that in the device for cutting globoid worms on a CNC lathe containing a plate on which the rotary part of the device is mounted in the form of a sector, which can be rotated along the guides around the vertical axis using a rotating mechanism, while notifying the tool mounted on the transverse support, the sector has gear teeth, and the rotating mechanism is made in the form of a gear rack, rigidly connected to the screw of a ball-screw pair, rotating from the step about the engine by CNC signals, while the cutter performs a circular motion around the axis of the sector at a distance from the axis of the worm, equal to the axis of the actual engagement.

The set of distinctive features, namely, that the sector has gear teeth, and the rotating mechanism is made in the form of a gear rack, rigidly connected to the screw of a ball screw pair, rotating from the stepper motor by CNC signals, while the cutter performs a circular motion around the sector axis on the distance from the axis of the worm equal to the axis of the actual engagement will allow roughing and finishing cutting of the globoid worm, i.e. expand technological capabilities, as well as increase processing productivity by automating the tuning process.

The applicant does not know the devices for cutting globoid worms on a CNC lathe of the claimed combination, and the claimed combination of essential features does not follow explicitly from the current level of technology, which confirms the compliance of the claimed technical solution with the patentability conditions of “novelty” and “inventive step”.

The claimed technical solution is illustrated by drawings, which depict:

FIG. 1 is a schematic illustration of a device for cutting globoid worms on a CNC lathe;

FIG. 2 - the same image of the position of the cutter and the workpiece;

FIG. 3 is a schematic representation of the engagement of the rack and gear sector;

FIG. 4-6 is a sequence of processing a profile groove;

FIG. 7, 8 - forms of incisors.

Globoidal worm gears are often used in rotary devices of machining centers and other mechanisms of industrial plants. The enterprise raises the issue of manufacturing globoid worms. Currently, there is no equipment that allows for quick setup of the machine and the precise manufacture of a globoid worm.

For the manufacture of globoid worms, it is proposed to modernize a CNC lathe with a center height of 750 ÷ 800 mm.

The devices for cutting globoid worms on a CNC machine shown in FIG. 1, comprises a plate 1 on which a rotary part of the device is mounted in the form of a gear sector 2, which can be rotated along the guides 3 around the vertical axis 4 by means of a rotating mechanism.

The rotating mechanism is made in the form of a gear rack 5, rigidly connected with a screw of a ball screw pair 6, rotating from a stepper motor 7 by signals of the CNC 8.

The cutter 9 is mounted on the transverse support in such a way that when the sector 2 is rotated, it is informed of circular movement, while the cutter performs circular movement around the axis 4 of the sector at a distance from the axis of the worm 10 equal to the axis of the real engagement (Fig. 2).

The housing of the rotating nut 11 of the ball screw pair 6 of the drive of the gear sector 2 and the motor 7 of the drive of the nut 11 are placed on the base plate 1.

To ensure rigidity, the right end of the base plate 1 (Fig. 1) is placed on an additional support plate 12, mounted on the guides of the machine behind the tailstock. This will allow you to perform installation movements of the gear sector relative to the workpiece of the globoid worm in both directions along the X and Z axes of the machine.

The contact surfaces of the base plate 1 and the supporting plate 12 must be grinded and greased with an ELIT-3000HD type grease (this grease is designed for operation under high loads in sliding friction pairs), install two electromagnets 13 from the bottom of the plate 12, turning them off after completing the installation movements of the base plate will provide the rigidity of the connection necessary for the rigidity of the entire system during processing.

The radius of the pitch circle of the gear sector 2 is selected constructively depending on the layout conditions and the diameter limits of the worm wheels intended for manufacture on the machine. To ensure a clearance-free gear sector 2 must be installed relative to the axis of rotation through a bearing (not shown).

It is proposed to rotate the gear sector 2 from the composite gear rack 5, rigidly connected to the screw of the ball screw pair 6, preferably with a step equal to or a multiple of the lead of the machine screw. Toothed sector 2 should rotate along a circular flat guide 3 mounted on a base plate. Composite gear rack 5 is necessary to adjust the clearance in the engagement of the rack-gear sector.

The axial movement of the screw occurs from the rotating nut 11. The nut 11 is mounted in the housing on bearings and receives rotation from the engine 7 through a toothed belt drive. It is proposed to use a drive with the “Z” coordinate of the lathe as an engine. This will make it possible, using a machine screw interpolator, to program any step of the worm gear.

The cutter 9, with which it is supposed to cut a groove on the worm, must rotate around the center O1 at a distance from the axis of the worm equal to the axis of the real engagement with the worm wheel (Fig. 2). For one revolution of the globoid worm, the cutter should move along the pitch circle by a step.

The machine should be able to configure the parameter “A” depending on the design of the actual meshing. Depending on the meshing module, the machine must be set to the specified step πm.

Cutter 9 (Fig. 2) is installed strictly symmetrically with respect to the O1O2 axis, otherwise a significant error may occur. When installing the workpiece (Fig. 2) under the globoid worm 10, it is possible to offset the axis O1X relative to the center of the worm O2, so that the axis O1X passes through point O2.

So, by programming the step πmi (Fig. 3), the gear rack 5 moves by this value and rotates the gear sector by the required angle “φ”, ensuring the cutting of the worm with the initial radius R1. From FIG. Figure 3 shows that the closer to the center of the gear sector 2, the smaller the πm value, which means that when programming the required step when cutting a helix on a globoid worm, it is necessary to take this into account for a given step of the πmr worm, programming a step equal to the value πmr × R1 / R2.

In addition to the above-mentioned installation movements of the fixture nodes, together with the tool, additional tool movements are required that do not affect the installation. Firstly, to withdraw the tool at the end of the stroke and additional movements.

Consider threading a globoid worm with a cutter 9. To remove the entire allowance, the cutter 9 must be periodically moved along the “X” axis by a certain amount Sn (transverse feed) and not only to ensure that the cutter works, and the cutter must be periodically shifted along coordinate Z ′ ′ (Fig. 2), so there must be an additional coordinate that allows you to move the cutter in the lateral directions. For this, it is proposed that two calipers be fixed on the gear sector with a slight displacement (within 40 mm) both along the X axis and along the Z axis (Fig. 2).

For the manufacture of globoid worms in small quantities, these additional movements can be performed manually according to indicators set by both additional coordinates, we will call hereinafter the tool coordinates. This is necessary for the subsequent installation of the tool in the initial position made during setup. At the beginning of cutting the profile groove, it is necessary to cut the groove with a rectangular cutter (Fig. 4), and then process the side surfaces (Fig. 5), after which it is better to finish the profile tool along the entire contour of the groove (Fig. 6). This requires a minimum of four tools. For ease of operation, it is necessary to use a tool with a constant distance of the axis of the cutting part relative to the installation base.

The groove cutter center of the width of the cutting part must also be with a certain distance relative to the mounting base UB (Fig. 7). The same requirements must be ensured along the length of the tool. For the profile tool, the same requirements apply. This will simplify processing and provide the necessary accuracy.

If it is necessary to cut globoid worms in batches, it is proposed to equip the additional coordinates X ′ ′ and Z ′ ′ with small-power step motors, since their task is to ensure periodic movements after the tool’s tool stroke. To do this, you can apply a compact drive to two coordinates. In additional coordinates, you can use the usual screw slip pairs, the play in the coordinates can be taken into account when programming the movement. The control transmission of the stepper motors of the coordinates X ′ ′ and Z ′ ′ can be carried out from a final sensor (not shown) mounted on the movement of the gear rack in its final position.

The device for cutting globoid worms on a CNC lathe of the claimed design allows to increase the technological capabilities and processing productivity.

Claims (1)

Fixture for cutting globoid worms on a numerically controlled lathe (CNC), containing a plate on which the rotary part of the fixture is mounted in the form of a sector, which can be rotated along the guides around the vertical axis using a rotary mechanism with the message that the tool is fixed in circular motion on the transverse support, characterized in that the rotary mechanism is made in the form of a gear rack, rigidly connected to the screw of a ball screw pair, rotating from the stepper company, the NC signals, and the teeth formed at the sector for meshing with said rack gear, and the cutter is mounted for circular motion around the axis of the sector away from the axis of the screw, equal to the distance in a real engagement of the worm with the worm wheel.

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