RU2304731C2 - Free-wheel clutch - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: free-wheel clutch comprises driving and driven clutch members and wedging device interposed between the clutch members. The wedging device is made of wedge-shaped blocks, wedging balls, and pressing springs. The wedging balls are set in the grooves provided with the wedge-shaped blocks and driven clutch member. The wedge-shaped blocks are secured to the driving clutch member by means of projections and hollows made in the wedge-shaped blocks and driving clutch member. The wedge-shaped block and driven clutch member could be provided with two or more grooves for receiving the wedging balls.

EFFECT: simplified structure, reduced metal consumption, and enhanced reliability.

1 cl, 7 dwg

Description

The invention relates to designs of overrunning clutches used in mechanical engineering, preferably in the field of engine manufacturing, to ensure the transmission of torque from the starter shaft to the crankshaft of the engine during start-up and automatic disconnection of the starter from the engine after it is started.

Known freewheel roller couplings, in which the rollers are jammed as a result of the occurrence of friction forces in the mating parts. Jamming of the roller occurs in the wedge part, made in the form of a segment of a logarithmic curve, an Archimedes spiral or arc with an offset radius along the line of contact of the roller with the outer and inner coupling halves. The amount of transmitted torque is provided by the length or number of jammed rollers in the coupling. To ensure reliable contact of the rollers with the working surfaces of the coupling halves, individual or group clamping devices are used [1].

During operation, a working out appears on the working surfaces, the jammed roller warps, the clamping devices break down and the coupling fails.

Another disadvantage of roller couplings is the low-tech manufacturing of the leading coupling half. According to the technological design, the leading coupling halves of the roller couplings can be extruded or welded. Each performance has its drawbacks:

- the welded structure is unreliable in operation due to insufficient strength of the welded joints and low accuracy of the joining of the welded parts;

- to obtain an extruded clip requires snap with a complex configuration of the punch, short-lived in the work and time-consuming to manufacture.

Known freewheel for driving a bicycle wheel, made in the form of wedges, movably located between the sprocket and the sleeve and interacting with the balls of the bearing [2].

However, a large number of parts in contact with the ball, which must be installed with a clearance to ensure free rotation of the bicycle wheel during overtaking, allow axial displacement of the balls, which can lead to failure of the clutch.

Known wedge overrunning clutches (freewheels), containing the outer and inner half-couplings and jamming elements located between them, each of which consists of two wedges mated together on a cylindrical surface [3]. However, these couplings do not allow high overtaking speeds and have large overall dimensions. Such couplings cannot be used for starting systems of internal combustion engines.

In the coupling of the proposed design, the jammed balls are in contact only with wedge crackers and one of the half-couplings, the wedge crackers are fixed, for which purpose stops are made in one of the half-couplings, preventing the movement of the wedge crackers. Balls are jammed in the wedge part, made in the form of a segment of a logarithmic curve, an Archimedes spiral or an arc with a shifted radius. To orient the movement of the balls in one of the coupling halves and in the wedge crackers, treadmills are made along the radius of the balls. The deepening of the balls in the coupling half and in the wedge crackers made it possible to obtain the contact of the ball along the generatrix, instead of the point obtained in ball bearings, and thereby reduce the stress concentration in the ball, the coupling half, and in the wedge crackers. The deepening of the balls in the coupling half and in the wedge crackers made it possible to significantly reduce the overall size of the coupling compared to a roller coupling of the same purpose.

Figure 1 shows a General view of the coupling of the proposed design; figure 2 shows the coupling in the context; figure 3 and 4 illustrate installation options wedge crackers; 5-7 illustrate embodiments of wedge crackers.

Description of the design of the proposed freewheel.

The leading coupling half 1 has a simple cylindrical shape, and the jammed part of the coupling (wedge cracker) 3 is made as a separate part. A ball 4 is used as a jamming element. In order to increase the length of the line of jamming of the ball 4, grooves along the radius of the jamming balls 4 are made on the contact surfaces of the wedge cracker 3 and the driven coupling half 2. The clutch is closed by a casing 6, which protects it from self-disassembling. If the outer diameter of the driven coupling half 2 is less than the diameter of the opening of the casing 6, between the driven coupling half 2 and the casing 6 are installed persistent half rings 7, which protect the driven coupling half 2 from falling out. To protect the coupling from dust and dirt getting into it, a sealing gasket 8 can be installed between the casing 6 and the persistent half rings 7.

In the design of the coupling, to prevent contact of the clamping spring 5 with the jamming balls 4, stops may be provided 9. To prevent radial displacement of the wedge crackers 3, protrusions 1a (or depressions 1b) are provided in the drive coupling half 1. Reliable fixation of the wedge crackers 3 can be ensured by one protrusion 1a (or depression 1b), the remaining wedge crackers 3 will be braked, resting against one another. To ensure reliable stop of the clamping spring 5 in the jamming ball 4 at the end of the wedge cracker 3, protrusions 3a are made, which cover the groove for installing the jamming ball 4. In the case of the leading coupling half 1 with trenches for fixing the wedge crackers 3 on the wedge crackers 3, hooks 3b are made.

Freewheel clutch operation. When the freewheel clutch is turned on, the driving coupling half 1 rotates relative to the still driven clutch coupling 2, the balls 4 jammed by the pressure springs 5 and the friction forces half-wedge 3 of the driving 1 and driven 2 coupling couplings move to a narrow part of the wedge space, and the clutch is jammed .

After starting the engine, the rotational speed of the driven coupling half 2 with gear 2a exceeds the rotation frequency of the driving coupling half 1; due to the frictional forces, the jammed balls 4 are squeezed into a wide part of the wedge space and the freewheel slips.

Information sources

1. Description of the invention to the copyright certificate SU 1032247 A1, M class. F16d 41/06.

2. Description of the invention to the copyright certificate SU 364491 A1, M class. F16d 41/24.

3. Description of the invention to the copyright certificate SU 333327 A, M class. F16d 41/07.

Claims (2)

1. The freewheel, closed by a casing and containing the leading and driven half-couplings and a jamming device located between them, consisting of wedge crackers, jammed balls and pressure springs, characterized in that the coupling jamming device is made by a separate element, and for placing jammed balls in the wedge the crackers and the driven coupling half have grooves along the radius of the jammed balls, while the wedge crackers are securely fixed in the leading coupling half by means of protrusions and depressions in the wedge uharikah and leading coupling half. 2. The freewheel according to claim 1, characterized in that the wedge cracker and driven half-coupling have two or more grooves for arranging jammed balls in two or more rows.

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