RU2399815C1 - Facility for conversion of rotation motion into progressive on base of rolling screw transmission - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: rolling-screw transmission contains screw with thread and roller with working surface in form of several rows of circular lugs. Thread on the screw and profiles of circular lugs on working surface of the roller are made rectangular. The circular lugs on working surface of the roller are arranged with twist t = stcosψ_s, where st is twist of screw thread, and ψ_s is angle of screw thread rise. Also the said circular lugs have width equal to half of step of the roller circular lug t / 2, while height is equal to height of projection of screw thread. Notably, axes of screw and roller cross at angle ψ_s of 3°-15° depending on number of starts and diametre of screw thread.

EFFECT: increased load capacity of transmission.

8 dwg

Description

The invention relates to the field of mechanical gears, containing mainly screw mechanisms with rollers, parts necessary for the use of these elements and converting the rotational movement of some links into the translational motion of others.

Known (Krainev AF Parts of machines. Dictionary-reference book. - M.: Mashinostroenie, 1992. - P.203, scheme a) a screw-roller gear including a screw and one or several rollers, the axis of the screw and rollers being parallel, moreover, the roller has the form of a nut with an inner diameter of thread greater than the outer diameter of the thread of the screw, and the pitch of the thread of the roller is equal to the pitch of the thread of the screw, but the angle of rise is different from the angle of the thread of the screw. The roller covers the screw so that its threaded protrusions enter the grooves of the screw thread and is mounted on bearings with the possibility of rotation about its axis in the housing.

The disadvantage of this roller-screw transmission is the high contact voltage between the threaded protrusions of the screw and roller, limiting the load capacity of the transmission.

Known (Krainev AF Parts of machines. Dictionary-reference book. - M.: Mashinostroenie, 1992. - P.203, scheme b) also a transmission containing a roller made in the form of a cylinder with an external thread that has the same step, like a screw, but a different angle of elevation. The roller is mounted on bearings with the possibility of rotation about its axis in the slider so that its threaded protrusions enter the grooves of the screw thread.

The disadvantage of this roller-screw transmission is the high contact voltage between the threaded protrusions of the screw and roller, limiting the load capacity of the transmission.

The closest in technical essence to the proposed device is a roller-screw drive (Krainev AF Machine parts. Dictionary-reference. - M .: Mechanical Engineering, 1992. - P.203, scheme c), in which the working surface of one of the links , usually a roller, is made in the form of annular protrusions having a profile similar to the thread profile, and arranged with a step equal to the thread pitch of the screw. In this case, for one revolution of the screw, the slider moves by the value of the thread stroke.

The disadvantage of this roller-screw transmission is the high contact voltage, limiting the load capacity of the transmission.

The purpose of the invention is to increase the load capacity of the roller-screw transmission.

This goal is achieved by the fact that in the screw-screw drive the screw thread and the profiles of the annular protrusions on the working surface of the roller are made rectangular.

The essence of the invention lies in the fact that the screw thread and the profiles of the annular protrusions on the working surface of the roller are made rectangular, while for the protrusions of the rollers to enter between the turns of the screw thread, it is necessary that the annular protrusions on the working surface of the roller are spaced

t = p _in cosψ _in

where p _in - thread pitch;

ψ _in - the angle of the thread of the screw,

and had a width equal to half the pitch of the annular protrusion roller t / 2, and a height equal to the projection of the screw threads, the screw axis and the roller are crossed at an angle ψ _which is 3-15 degrees depending on the number of entries and the diameter of the screw thread.

Figure 1 presents a diagram of a roller-screw transmission with inner ring protrusions of a rectangular profile, while the axis of the roller and screw are crossed at an angle ψ _in , which is 3-15 degrees, depending on the number of entries and the diameter of the screw thread, in figure 2, Figures 3 and 4 show sections and sections of the circuit nodes, Fig. 5 shows a diagram of a roller-screw transmission with outer annular protrusions of a rectangular profile, while the axis of the roller and screw are also crossed at an angle ψ _in , is 3-15 degrees depending on the number approaches and diameter screw threads, FIGS. 6, 7, 8 show sections and cross-sections.

In Fig.1, the scheme of the screw-screw transmission includes a roller 1 with inner annular protrusions, a screw 2, bearings 3 and 4, mounted on the base 5. The roller 1 is mounted in a slider 8 arranged to move in parallel with the help of angular contact bearings 6 and 7 the axis of the screw 2 in the guides 9, also fixed on the base 5.

In Fig. 5, the scheme of a roller-screw transmission includes a roller 10 with outer annular protrusions, which is mounted by means of angular contact bearings 6 and 7 in a slider 8 arranged to move parallel to the axis of the screw 2 in the guides 9, also fixed on the base 5, and screw 2 is mounted on supports 3 and 4, mounted on the base 5.

The proposed device operates as follows.

To ensure guaranteed contact quality at various angles of thread elevation and parallel axis of the links, a convex threaded profile or an annular protrusion profile is provided. As a result, there is a point contact of the threaded screw protrusions and the annular projections of the rollers and, as a result, high contact stresses that reduce the transmission load capacity.

Figure 1 shows that when the screw 2 is rotated, the roller 1 is drawn into rotation in the same direction as the screw 2 by friction forces on the side surfaces 11 of the contact profiles 12, 13. In one revolution of the screw 2, the roller 1 together with the slider 8 moves along the guides 9 to a distance equal to the thread stroke, while the direction of rotation of the screw 2 counterclockwise, and the accepted direction of the thread - right - determines the progressive movement of the slider 8 towards the support 4.

This relative arrangement of the screw and the roller, when the axes are crossed at an angle ψ _in , which is 3-15 degrees depending on the number of entries and the diameter of the screw thread, causes the contact of the side surfaces of the threaded and annular protrusions to change from point to plane (Fig. 2, 3 ), thereby increasing the load capacity of the roller-screw transmission.

In the case of the external location of the screw relative to the roller (Fig. 5), when the screw 2 is rotated, the roller 10 is involved in rotation in the opposite direction relative to the direction of rotation of the screw 2 by friction forces on the side surfaces 11 of the contact profiles 12, 13. For one revolution of the screw 2, the roller 10 together with the slider 8 will move along the guides 9 to a distance equal to the thread stroke, while the direction of rotation of the screw counterclockwise, and the accepted direction of the thread - right - determines the progressive movement of the slider 8 towards the support 4.

This mutual arrangement of the screw and the roller determines the transition of the contact of the side surfaces of the threaded and annular protrusions from point to plane (Figs. 7, 8), thereby increasing the load capacity of the roller-screw transmission.

Thus, the proposed device allows to increase the load capacity of the roller-screw transmission due to the transition from the point contact of the surfaces of the threaded and annular protrusions to the contact along the planes, while the roller-screw transmission with a roller with internal ring protrusions is more compact and provides a larger contact area of the threaded protrusions with annular with respect to the roller-screw transmission with a roller with outer annular protrusions.

Claims (1)

A device for converting rotational motion into translational motion on the basis of a roller screw drive, comprising a threaded screw and a roller with a working surface in the form of a series of annular protrusions arranged in increments equal to the thread pitch of the screw, both with internal and external annular protrusions of a rectangular profile, characterized in that the thread on the screw and the profiles of the annular protrusions on the working surface of the roller are made rectangular, while for the protrusions of the rollers to enter between the turns of the screw thread, it is necessary that the annular projections on the working surface of the roller were arranged at a pitch p _in t = cosψ _in where p _in - pitch of the screw thread; ψ _in - the angle of the thread of the screw, and had a width equal to half the pitch of the annular protrusion of the roller t / 2, and a height equal to the height of the protrusion of the thread of the screw, and the axis of the screw and roller are crossed at an angle ψ _in , which is 3-15 ° depending on the number of visits and the diameter of the screw thread.

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