WO2008007996A1 - Transmission provided with intermediate members - Google Patents

Abstract

The invention relates to mechanical engineering and can be used in drives for highly accurate and heavy-loaded machines. The main aim of said invention is to develop a transmission provided with intermediate members, which makes it possible to improve the performance characteristics and to simultaneously increase the accuracy thereof. The inventive transmission provided with intermediate members comprises a body, drive and driven shafts, a cam having a cone working surface and an axial adjustment device mounted on a central shaft, a central internally toothed wheel and a casing provided with intermediate members, which are arranged in a row in the grooves thereof and are used for interacting with the cam and the internal teeth of the central wheel, wherein the generating line of the side surface of said internal teeth of the central wheel is positioned at an angle with respect to the central axis thereof.

Description

 Intermediate Transmission

Technical field

The invention relates to mechanical engineering and can be used in drives of high-precision and heavily loaded machines.

State of the art

Known transmission with intermediate links (description to the patent of the Russian Federation JNs 1770650 Al, MKI: F 16 H 57/12) comprising a housing, drive and driven shafts, a cam mounted on the drive shaft, a central wheel with internal teeth, made in the form of a set of at least at least two rings and a clip rigidly connected to the driven shaft, intermediate links arranged in the grooves of the last rows for interaction with the cam and the central wheel, the gear provided with a turning device made in the form of a tangential or radially located to the central Nome wheel threaded rods connected to the housing, one of the sets of rings fixedly installed in the housing, and another - with a rotatable and has a recess on the outer surface for engagement with the rods.

The disadvantage of this transmission is not a high efficiency due to deviations in the geometry of the internal teeth (step difference, accumulated pitch errors, unequal tooth geometry, etc.) of the fixed and rotary central wheels. In addition, this device has a complex structure and insufficient bearing capacity, which is limited by the low rigidity and strength of the threaded rods at their contact with the swivel wheel.

The closest technical solution, selected as a prototype, is a transmission with intermediate links (description to RF patent JNi- 1716227 Al ₅ MKI: F 16H57 / 12, 1/00) comprising a housing, a drive shaft and a driven shaft, a cam mounted on the drive shaft, a central wheel with internal teeth fixedly mounted in the housing, a clip rigidly connected to driven shaft, and intermediate links located in the grooves of the cage for interaction with the cam and the Central wheel. In this case, the transmission is equipped with an axial adjustment element located between the housing and the cam, the latter has the possibility of axial movement, and its working surface is conical. In the known transmission with intermediate links, when transmitting torque from the input shaft to the output, the axial forces begin to act on the intermediate links. These are axial components of the normal forces arising on the conical surface of the cam in places of its contact with the intermediate links. Axial forces press the intermediate links to the end walls of the grooves of the ferrule and in the places of their contact, significant friction forces arise, which reduce the efficiency transmission. The greatest friction losses occur when intermediate bodies are made in the form of rollers and friction forces occur at the ends of these rollers.

In addition, a significant amount of axial movement of the cam, i.e. the axial adjustment device must have a large adjustment stroke, which complicates the design. The stroke can be reduced by increasing the angle of the cam cone. However, this entails an increase in the axial component from the normal forces acting on the intermediate links, and, consequently, an increase in the friction forces.

The disadvantage of this transmission is its low efficiency, due to the occurrence of axial friction between the rolling bodies and the surfaces of the grooves of the clip.

SUMMARY OF THE INVENTION The main task to be solved by the claimed invention is aimed at creating a transmission with intermediate links, providing an increase in efficiency while increasing its accuracy.

The problem is achieved in that in a transmission with intermediate links comprising a housing, drive and driven shafts, a cam with a cone-shaped working surface and an axial adjustment device mounted on the drive shaft, a central wheel with internal teeth and a cage, with rows of intermediate located in its grooves links for interacting with the cam and with the inner teeth of the central wheel, the inner teeth of the central wheel have a side surface, the generatrix of which is located at an angle to its center ral axis.

This transmission with intermediate links has the following advantages. To increase the efficiency gears with intermediate links while increasing its accuracy, it is necessary to reduce friction losses between the intermediate links and the walls of the grooves of the cage. For this, the inner teeth of the central wheel are cut so that the generatrix of the side surface of these internal teeth forms an angle with the central axis of the central wheel. As a result, the internal teeth represent a complex profile evenly tapering toward the central axis. Currently, the most progressive method of cutting the teeth of the central wheel for such gears is cutting teeth on EDM wire-cutting machines. This tilt of the teeth is easily performed by shifting the upper or lower guide of the cutting wire, which forms the side surface of the teeth of the Central wheel. When the intermediate links move along the inclined teeth, the axial components of the force act on them, from the normal forces in the places of contact with the teeth, which are opposite in direction to the axial components from the action of normal forces in the places of contact with the conical surface of the cam. If these forces are equal and opposite in direction, then they mutually destroy each other and the intermediate links are in equilibrium. In this case, between the intermediate links and the walls of the grooves of the cage, there is no friction during movement. The absence of such friction increases the efficiency gears with intermediate links. The presence of the axial cam control device allows you to adjust the gaps in the transmission up to their complete elimination. In this case, the accuracy of the transmission increases. With the simultaneous inclination of the working surfaces of the teeth and the cam, the length of movement with the help of an axial adjustment device is halved. The angle of inclination of the working surfaces of the teeth and the cam can be set by any one based on the design requirements. An increase in the angle of inclination significantly reduces the course of adjustment in the axial adjustment device.

Brief Description of the Drawings

In FIG. 1 shows a transmission structure with intermediate links.

In FIG. 2 transverse section of the transmission with intermediate links. In FIG. 3 is a three-dimensional view of a fragment of a central wheel with internal teeth.

An example embodiment of the invention

The transmission with intermediate links (Fig. 1) contains a housing 1 with a central wheel 2 with internal teeth fixedly fixed in it 3. The generatrix of the side surface of the internal teeth 3 of the central wheel 2 forms an angle β with its central axis (Fig. 1, Fig. 3) . In the housing 1 (Fig. 1, Fig. 2), a drive shaft 5 is mounted on the support 4, made integral with the cam 6 eccentrically placed on it, having a cone-shaped working surface. The cam 6 interacts with the intermediate links 7 (balls), which are placed in the radial grooves of the cage 8, combined with the driven shaft 9. Between the support 4 and the cam 6 there is an axial adjustment element made in the form of a distance washer 10.

The transfer works as follows.

When the drive shaft 5 rotates, the cam 6 rotates with it, orbiting in a circle with a radius equal to the eccentricity of this cam, while the balls 7 are given radial movement and interacting with the side surfaces of the inner teeth of the central wheel 2, they press on the side surfaces of the teeth , and due to the occurrence of radial forces are shifted also in the circumferential direction. Moving relative to the stationary housing 1 and the central gear 2, the balls 7 carry along with themselves in the circumferential direction and the clip 8, in the grooves of which they are located. In this case, together with the clip 8, the driven shaft 9 rotates. b

Transmission clearances are cleared in the following order: cam

6 moves axially to the driven shaft 9, while its cone-shaped working surface pushes the balls 7 until they come into contact with the inclined surfaces of the teeth of the Central wheel 2, thereby selecting the clearances in engagement. In the resulting space between the cam 6 and the support 4, a distance washer 10 of the corresponding thickness is installed, ensuring the preservation of the relative position of all transmission elements after adjustment. When transmitting torque from the drive shaft 5 to the driven shaft 9 at the points of contact of the balls

7, with the cone-shaped working surface of the cam b and with the inclined surfaces of the inner teeth of the central wheel 2, oppositely directed normal forces arise. Due to the inclination of these forces to the central axis, oppositely directed axial components of these forces arise. When the angle of inclination of the contact surfaces of the cam 6 and the inner teeth of the Central wheel 2 are equal, these axial components of the force are equal, opposite in direction and mutually destroy each other. This ensures the equilibrium position of the balls 7 in the axial direction, as a result of which they are not pressed against the end walls of the radial grooves of the cage 8 and do not create friction forces. Due to this, the efficiency increases gears with intermediate links. Due to the angle of inclination of the working surfaces of the cam 6 and the inner teeth of the central wheel 2, the value of the axial adjustment is very small and can be done by grinding the distance washer 10.

Industrial applicability The inventive transmission with intermediate links allows increase efficiency while improving accuracy.

The inventive transmission with intermediate links can find application in the construction of high-precision gears, which should have small dimensions and weight, high bearing capacity and high efficiency For example, in the aviation industry and rocket science in servo antenna drives, wing and aileron steering drives, antenna disclosure drives, metering devices, etc. In mechanical engineering, in drives of dividing tables, in feed drives, in reading and measuring devices.

Claims

CLAIM A gear with intermediate links, comprising a housing, drive and driven shafts, a cam with a cone-shaped working surface and an axial adjustment device mounted on the drive shaft, a central wheel with internal teeth and a cage, with rows of intermediate links located in its grooves for interaction with the cam and the inner teeth of the Central wheel, characterized in that the internal teeth of the Central wheel have a side surface, the forming line of which is located at an angle to its Central axis.