RU2388952C2 - Tensioning equipment - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: tensioning equipment consists of case (1) with screw surfaces, of stop bushing (6), of spring loaded rod (3) and of heel (5). Screw surfaces with one or more starts are made on the rod. To facilitate arrest of the spring before actuating there is made a lengthwise slot in the case. Complex spring (4) of compression-torsion is used for rod spring loading; a working lever of the spring enters the slot of the heel and lengthwise slot of the case. The slot of the case can be arranged at angle to an axle. The axle of the heel is made conic or there is made a slanted flat on it.

EFFECT: low prime cost of fabrication at mass production, stable parametres of tension during whole service life, long lifetime, light weight and improved operational characteristics.

7 cl, 6 dwg

Description

This invention relates to the field of engine building and can be used on internal combustion engines (ICE) to tension the belts (chains) of the drive of the main and auxiliary units (generator, air conditioning, etc.).

Known mechanical chain tensioner (Car repair "Moskvich" models 2140, 2138. M., Transport, 1983, p. 11, 14 and 16) containing a plunger, a spring that acts on the heel, and a locking bolt that fixes the position tensioner after sampling the gap (pull-up).

The disadvantage of this device is the lack of automatic tracking of the position of the circuit.

Known hydraulic tensioning device (RF patent No. 2110715), comprising a housing with a blind cylindrical groove and a piston mounted in the groove with the possibility of movement. The piston to ensure chain tension interacts with the fifth in contact with the endless transmission. An opening is made in the bottom of the groove connected with a source of liquid under pressure. The bypass valve is made in the form of an elastic bendable plate covering this hole. The disk is divided by the cut line into the central part forming the elastic plate and the peripheral part connected to the central - connecting part. The peripheral part is held at the bottom of the groove with the help of a pressure coil spring installed in the groove between the piston and the disk. The spring has coils of constant diameter at one end and coils of increasing diameter at the second end in the direction of removal from the first end. The tensioning device comprises a piston stroke restriction shoulder made in the side wall of the groove, as well as a radial clearance between the piston and the side wall of the groove, forming a calibrated fluid passage under pressure.

This device is difficult to manufacture and requires the supply of oil pressure, and consequently, an additional oil supply system, which increases the cost of construction.

A hydraulic tensioning device is known (RF patent No. 2197654), comprising a housing located in its cylindrical cavity, axially spring-loaded plunger and an adjusting rod closed with a union nut from the housing end, additionally equipped with a clearance compensator fixed to the end of the tensioner housing, under the union nut, made in the form of a fluid-filled housing, in the cylindrical cavity of which is located a piston spring-loaded in the direction of the adjustment rod with through longitudinal to with analges and an annular groove on the outer cylindrical surface with a sealing ring installed in it, while an elastic membrane is installed between the tensioner housing and the hydraulic compensator housing.

The disadvantage of this device is the restriction on the angle of inclination, based on the performance of the hydraulic compensator, and the need to supply oil pressure.

A hydraulic tensioning device is known (RF patent No. 2154760), comprising a hollow cylindrical body, a cover with a check valve, a power spring, a plunger made in the form of a cup and making up a precision pair with the body. On the plunger there are a number of annular grooves of an asymmetric profile, and on the body there are radial holes with latches located in them, having a spherical surface in contact with the grooves on the plunger. The latches are pressed against the grooves on the plunger by means of an elastic ring. An additional extreme groove on the side of the open end of the plunger has a section of a rectangular profile.

The disadvantages of the existing device are the need to ensure high precision manufacturing of precision pairs and discrete changes in position, as well as the supply of oil pressure.

Known tensioning device (No.2000128233 publ. 2002.10.10), consisting of a housing, a spring-loaded rod with a reverse braking mechanism and mounting eyes with rubber-metal hinges, characterized in that the reverse braking mechanism is made in the form of a wedge ball lock, an additional wedging sleeve is installed and in one of the eyes, an in-depth chamfer is made for the entrance of a special tool for wedging, and the power spring is located outside the stem and body, radial holes are formed in an elastic washer for for balls, and in the case an additional groove is made for fixing the device in a compressed state - an analogue.

The disadvantages of the existing device are high contact stresses in the places of interaction of the balls and the rod, which leads to premature wear.

The task is to create a device for tensioning belts (chains) of the drive of auxiliary units, not critical to the angle of inclination of the working position, without supplying oil pressure, with a large supporting working surface to increase service life.

This goal is achieved due to the fact that in the tensioner, consisting of a housing, a thrust sleeve, a spring-loaded rod and a supporting heel, according to the invention, screw surfaces are made on the rod in one or more passes; a longitudinal slot is made in the housing for locking the spring until it is actuated, moreover, this slot can be located at an angle to the axis; the axis of the supporting heel is made conical or oblique flat is made on it; as a store of potential energy, a combined compression-torsion spring is used, and the coil of the spring can be wound by a sinusoid; a slip tube was used to reduce friction and wear.

This device is presented in Fig.1-6, where:

figure 1 shows a longitudinal section of the device in the delivery state (before installation on the engine) with positions-callouts of all parts.

Figure 2 shows a section aa to explain the closure of the working lever of the combined spring 4 in the slots of the supporting heel 5.

Figure 3 shows a longitudinal section of the device BB in the perpendicular plane of Figure 1, but already in an intermediate working position (the engine and the tension mechanism with a chain are not conventionally shown). The interaction of the support heel 5 with his shoulders with the end surface of the rod 3 and the extension of the rod 3 is demonstrated.

Figure 4 shows a perspective view of the supporting heel 5 with an oblique flat.

Figure 5 shows a perspective view of a longitudinal slot in the housing 1 at an angle to its axis and the type of locking of the working lever of the combined spring 4 in this slot.

Figure 6 shows a local sectional view of the device, similar to Figure 1, but with a supporting heel 5, which has a conical axis.

In the initial state (delivery state), the device is shown in FIG. 1:

the tensioner consists of a thin-walled tubular housing 1 connected by welding to a standard flange 2, by which the tensioner is attached to the engine; thin-walled tubular rod 3 with helical surfaces; combined (tension-compression) spring 4, the working arm of which enters the groove of the support heel 5 rolled on one side, the slotted hole in the rod 3 and the longitudinal groove of the housing 1 (before actuation) - axonometric projection of this connection is shown in Figure 5.

With the support arm, the combined spring 4 enters the through hole of the thrust sleeve 6, the outer edges of which are used to roll the housing 1. In this way, the thrust sleeve 6 is kept from turning and axial movement. A sealing ring 7 is placed in the annular groove of the thrust sleeve 6 to prevent leakage of oil from the internal cavity of the engine (not shown in the drawing) and dirt entering the engine. For greater reliability, the thrust sleeve 7 can be rolled into the housing 1.

Between the rod 3 and the spring 4 can be placed a sliding tube 8 to reduce friction and wear during operation.

The order of assembly of the tensioning device: weld the housing 1 with the flange 2, and to fix the position before welding on the flange 2 can be molded protrusions (Figure 3) with the possibility of entry into the screw surfaces of the housing 1. On the thrust sleeve 6 put on the sealing ring 7 and thread the support spring lever 4. This subassembly is installed in the housing 1 and rolled. A slide tube 8 is mounted on the spring 4 (if its use is necessary), and then a screw rod 3. The operating lever of the spring 4 is threaded into the slot of the support heel 5 and squeezing it down with a conical axis or oblique flat (axonometric view of the support heel 5 with oblique flat is shown in Fig. 4, and with a conical axis in Fig. 6), they are inserted into the slotted hole of the stem 3. The spring 4 is pressed together with all the parts until it contacts the housing 1, where the stem 3 is screwed into the housing 1 along the counter screw surfaces. fully spun stock 3 secondary about the supporting heel 5, the working lever of the spring 4 is pressed down and brought into the slot of the housing 1, after which the supporting heel 5 is released (Figure 2). In this position, the tensioner is transported and mounted on the engine.

Due to the loaded work of the rod 3, the contact area of the supporting working surface with the housing 1 can be increased with an increase in the number of visits of screw surfaces to increase the resource. A limitation can only be the technological capabilities of the equipment. It is proposed to use high-performance methods of stamping with an elastic medium and magnetic pulse stamping, which practically exclude subsequent machining and minimize waste. Thanks to this, a high economic effect is achieved.

The presence of screw surfaces on the stem 3 allows it to elastically damp jerks and shocks coming from the actuators of tension, which has a beneficial effect on increasing the resource of all parts.

There is no great need to perform screw surfaces on the housing 1 - they can be replaced by cyclic protrusions along which the rod 3 will slide. However, the contact area in this case will be much smaller.

A longitudinal slot on the toe of the housing 1 can be made at an angle to the axis (Figure 5) to prevent the working lever of the spring 4 from slipping in a compressed state. The angle is chosen close to the angle of inclination of the turns of the helical surface. Instead of a slot, a conventional hole can also be made, but in mass production this operation will be less productive.

The need to use a combined spring 4 is due to the operation of the tensioning device: to unscrew the rod, not only the tangential component of the twisting moment will be required, but also the axial force to overcome the elastic forces of the engine chain (belt); their ratio is about 4/1. Due to the large number of turns, the axial force remains almost constant in the range of the stroke of the rod 3, which makes it possible to refuse to supply oil pressure and provide the required chain (belt) tension throughout the life of the engine. However, the torsion moment and the twist angle are more demanding on the number of turns, which can be increased by applying the sinusoidal winding of the spring 4. This allows you to add about 20% of the turns, which is the only way with a tight layout of the engine compartment and the tight dimensions of the tensioner. At the same time, the area of the contacting surfaces of the spring 4 and the rod 3 is reduced (without the use of the slip tube 8), and consequently, friction and wear.

When the use of a sinusoidal spring 4 may be ineffective, use the sliding tube 8. It can be made of materials with a low coefficient of friction, such as polytetrafluoroethylene (PTFE). As a result, the movement of the coils of the spring 4 and their unwinding will occur along the smooth cylindrical surface of the sliding tube 8.

The supporting heel 5 has a mushroom shape (Figure 5), the spherical surface of which it abuts against the actuator of the tension chain (belt) of the engine. A longitudinal slot provides axial movement of the support heel 5 relative to the working lever of the spring 4 during assembly and stragging. The conical axis (Fig.6) or oblique flat provide deformation of the working lever of the spring 4 during assembly and stragging (Fig.2).

The operation of the tensioning device in the conditional average operating position is shown in FIG. 3.

After installing the tensioning device on the engine, it is necessary to disengage the working lever of the spring 4 from the slot on the nose of the housing 1. For this, the supporting heel 5 is inserted into the tensioning device by the actuating mechanism of the engine tension. The conical axis or the conical surface of the oblique flats of the supporting heel 5 begin to squeeze the radius portion of the working lever of the spring 4 (Figure 2). As soon as the working lever of the spring 4 comes out of engagement with the wall of the slot on the nose of the housing 1, it will begin to interact with the surface of the slotted hole in the stem 3. Overcoming friction in the screw pair and in the places of contact of the turns of the spring 4 with the sliding tube 8 (or rod 3 in the general case ), as well as the elastic forces of the actuators of the engine, the rod 3 begins to twist out of the housing 1 under the action of the accumulated potential energy of the combined spring 4. The supporting heel 5 rests its shoulders on the end surface of the rod 3.

The extension of the rod 3 ends in any equilibrium position, when all the forces attributable to the rod 3 are balanced. This ensures the initial tension of the actuators of the engine.

In the process of engine operation, wear of mechanisms occurs, which leads to an increase in the length of the chain (belt). The equilibrium point is shifted outward from the tensioner. Due to the presence of the combined spring 4, this new position is constantly monitored by unscrewing the rod 3.

The presence of vibrations and oil mist during engine operation will facilitate the movement of both the rod 3 along the housing 1 and the coils of the spring 4 along the sliding tube (rod 3).

Small short-term movements of the tension actuators associated with jerking and unbalanced operation of the engine are compensated for by the gaps between the screw surfaces of the rod 3 and the housing 1 (and their elastic deformation) without rotation of the rod 3. The resulting stresses are distributed over a large area of contacting working bearing surfaces formed Multiple helical bends, which together with the present oil mist significantly reduce wear.

When repairing an engine that requires loosening the chain tension, the tensioner is either removed and recharged as in the initial assembly, or if access is available, screw the stem 3 into the housing 1 without removing the device, which distinguishes it from analogues.

Thus, the proposed tension device has a low manufacturing cost for mass production, stable tension parameters throughout the entire service life, a large resource, low weight and improved performance.

Claims (7)

1. A device for tensioning a chain (belt) of a drive of mechanisms, comprising a housing with screw surfaces, a thrust sleeve with a through hole installed therein, a support heel, a spring, a support arm of which enters a through hole of the thrust sleeve, a spring-loaded rod with screw surfaces, reciprocal screw surfaces of the housing, characterized in that a combined compression-torsion spring is used for springing the stem, a slot is made in the heel and a longitudinal slot is made in the housing for locking the spring, working the lever of which is included in the slot of the supporting heel and the longitudinal slot of the body. 2. The device according to claim 1, characterized in that the turns of the spring are wound by a sinusoid. 3. The device according to claim 1, characterized in that the axis of the supporting heel is made conical. 4. The device according to claim 1, characterized in that the longitudinal slot for locking the spring is made in the housing at an angle to its axis. 5. The device according to any one of claims 1 to 3, characterized in that it is equipped with a slide tube, which is mounted on a compression-torsion spring. 6. The device according to any one of claims 1 to 3, characterized in that the oblique flat is made on the reference heel. 7. The device according to claim 4, characterized in that the oblique flat is made on the heel.

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