RU2550972C2 - Tensioning device - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention relates to machine building and can be used to create preload in belt transmission systems. A tensioning device comprises a shaft, a pivot arm mounted on the shaft and able of turning around the axis, a friction bush installed between the shaft and the pivot arm, an upper plate fitted with a stop to limit the rotation range of the pivot arm and rigidly mounted on the shaft, a torsion spring set on the shaft between the pivot arm and the torsion spring, a pulley set on the pivot arm. The rotation centre of the pivot arm is located eccentrically in relation to the rotation centre of the upper plate. The pivot arm is fitted by a lug interacting with the tension indicator on the plate. The pivot arm consists of two parts rigidly coupled with each other, the first pivot arm part is fitted by a groove into which the second torsion spring is inserted and set between the shaft and the first pivot arm part. The shaft has a flange on one end where the groove for the second torsion spring is provided.

EFFECT: longer service life of a tensioning device.

10 dwg

Description

The invention relates to mechanical engineering and can be used to create a preliminary load in belt transmission systems.

It is known "The device of the belt tension of the drive mechanism of the engine of the car" (RF patent No. 2452885, IPC F16H 7/12, published on 10.06.2012, Bull. No. 12), containing a roller and a bearing pressed into the roller seat. An opening is made in the central part of the roller eccentrically with respect to its axis, in which a sleeve is rotatable and rotatable. An eccentric hole is made in the sleeve with a displacement of its axis away from the axis of the roller. In the hole of the sleeve is installed means of rotation of the sleeve. The bracket for mounting the roller to the engine housing has a locking element on which one end of the working spring is engaged. The thrust lever connected to the roller is connected at one end to the sleeve, and a fixing element is made at its other end, on which the second end of the working spring is engaged. Between the roller and the sleeve is located on the sleeve and connected to the bracket guide sleeve so that the axis of the guide sleeve with respect to the axis of the roller has an eccentricity.

EFFECT: invention provides softness of damping of alternating loads on the engine gas distribution mechanism.

A disadvantage of the known device is a narrow damping range of alternating loads due to the use of a spring for compression and tension and a relatively small service life due to the design features of the bracket that determines the movement of the rotary sleeve.

It is known "Tension device and installation unit" (RF patent No. 2422701, published 06/27/2011, Bull. No. 18), containing a base having a shaft rigidly connected to it, a pivot arm mounted to rotate on the shaft, a pulley mounted on a rotary the lever rotatably, a spring engaged between the base and the pivot lever. A friction sleeve is located between the pivot arm and the shaft. The holding element is rigidly attached to the shaft opposite the base. The pivot arm and spring are located between the holding member and the base. The first hole in the base, the second hole in the holding member and the shaft hole cooperate with the fastener. The axis of the hole in the base is offset by a predetermined distance from the axis of rotation of the pivot arm, and the axis of rotation of the pulley is offset by a predetermined distance from the axis. The socket for placing the tool is made in the holding element. The base, the shaft and the holding element are rigidly connected to each other with the formation of a rigid installation site so that the entire installation site rotates as a unit during installation. There is no relative movement between the base, the shaft and the retaining element during installation. The invention allows you to set and adjust the tension of the belt.

A disadvantage of the known device is the reduction of the service life due to the complex design of the mounting unit (holding element, shaft, base) and the skew of the friction sleeve with a low coefficient of friction, located between the hollow shaft and the pivot arm, arising from the use of one spring and an asymmetric design.

A known device-prototype "Tension device" (RF patent No. 2449189, published 04/27/2012), containing a shaft having a part of the shaft, made with the possibility of engagement with the mounting surface, a pivot arm mounted on the shaft with the possibility of rotation around the axis, the plate, rigidly mounted on the shaft and located on the shaft end opposite the shaft part, a torsion spring engaged between the pivot arm and the plate to bias the pivot arm. The torsion spring is located opposite the shaft and directly adjacent to the plate. The pulley is mounted on a swing arm. The center of rotation of the pivot arm is eccentric relative to the center of rotation of the plate. The pivot arm has an eye that interacts with a part on the plate to indicate the relative position of the pivot arm relative to the plate during installation, and a part for positioning the tool on the plate for rotational adjustment of the plate during installation. The invention allows to maintain a relatively constant tension of the belt in all ranges of engine temperature and to provide a means of compensating for the dynamic characteristics of the belt and belt transmission during load fluctuations.

A disadvantage of the known prototype device is the reduction of the resource of the device. The reason preventing the achievement of a greater resource when using the known prototype device is the skew of the pivot arm and increased wear of the friction sleeve located between the shaft and the pivot arm, as well as the fatigue of the torsion spring under alternating loads.

The skew of the pivot arm occurs due to the use of a single spring and the asymmetric design of the device.

The main task, the solution of which the claimed object "Tension device" is directed, is to create a symmetrical design using two torsion springs that carry less load.

The technical result achieved by the implementation of the claimed invention is to increase the life of the tensioner

The specified technical result is achieved by the fact that in the known device comprising a shaft, a pivot arm mounted on the shaft with the possibility of rotation around the axis, a friction sleeve installed between the shaft and the pivot arm, a plate made with a stop to limit the rotation range of the pivot arm and rigidly fixed on the shaft, a torsion spring engaged on the shaft between the pivot arm and the plate, a pulley mounted on the pivot arm, the rotation center of the pivot arm being eccentrically relative to the center of rotation of the plate, while the pivot arm has an eye that interacts with a tension indicator on the plate, the pivot arm is made of two parts that are rigidly interconnected, the first part of the pivot arm has a groove in which a second torsion spring is inserted between the shaft and the first part of the rotary lever, the shaft is made with a flange at one end, in which a groove is formed for installing the second torsion spring. The implementation of the pivot arm of two parts, rigidly interconnected, the introduction of a second torsion spring, creating a symmetrical design allows you to increase the service life, therefore, the claimed invention meets the condition of "novelty."

Search results for known technical solutions in this and related fields of technology in order to identify features that match the distinctive features of the claimed invention from the prototype have shown that they do not follow explicitly from the prior art.

From a certain level of technology, the popularity of the influence of the transformations provided for by the essential features of the claimed invention on the achievement of the specified technical result is not revealed - increasing the resource of work, and the invention is based on:

- supplementing the known analogue device with a second torsion spring installed between the shaft and the pivot arm to compensate for the warping moment of forces resulting from the action of one torsion spring;

- changing the design of the shaft of the analog device using a flange with a groove for installing an additional torsion spring;

- changing the design of the pivot arm — forming the pivot arm of two parts rigidly interconnected, and adding to one of the parts of the flange with a groove for installing an additional torsion spring.

The invention is illustrated by drawings, where:

figure 1 is a view with a spatial exploded elements of the tensioning device according to the present invention;

figure 2 presents a top view in perspective of the first part of the pivot arm, the second part of the pivot arm and shaft;

figure 3 presents a bottom view in perspective of the second and first parts of the rotary lever;

figure 4 presents a top view in perspective of the first and second parts of the pivot arm;

figure 5 presents a bottom view in perspective of the shaft and the pivot arm;

6 is a top perspective view of a plate, a pivot arm, and a shaft;

figure 7 presents a top view in perspective of the second part of the pivot arm;

on Fig presents a side view in perspective of a pulley with bearing and the first part of the pivot arm;

figure 9 presents the first torsion spring.

The following notation is introduced:

1 - shaft;

1.1 - the inner surface of the shaft;

1.2 - shaft flange;

1.3 - groove of the shaft flange;

1.4 - slot flange of the shaft;

1.5 - the outer surface of the shaft;

2 - friction sleeve;

3 - the first torsion spring;

3.1 - the first element of the first torsion spring;

3.2 - the second element of the first torsion spring;

4 - the first part of the rotary lever;

4.1 - element of the first part of the rotary lever for engagement with the first torsion spring;

4.2 - flange of the first part of the rotary lever;

4.3 - flange groove of the first part of the rotary lever;

4.4 - the outer surface of the first part of the rotary lever;

4.5 - guide grooves of the first part of the rotary lever;

4.6 - element of the first part of the rotary lever for engagement with the second torsion spring;

5 - bearing;

6 - a pulley;

7 - the second part of the rotary lever;

7.1 - guiding protrusions of the second part of the rotary lever;

7.2 - protrusion 1 - "emphasis with a hot engine";

7.3 - ledge 2 - "emphasis with a cold engine";

7.4 - ear;

7.5 - an element for forming a groove under the second torsion spring;

8 - second torsion spring;

8.1 - the first element of the second torsion spring;

8.2 - the second element of the second torsion spring;

9 - plate;

9.1 - groove for fixing the second torsion spring;

9.2-emphasis;

9.3 - tension indicator;

9.4 - hole plate;

10 - mounting element.

Figure 10 presents the plot of the forces acting on the pivot arm from the side of two torsion springs. The following notation is introduced:

1 - the point of application of the force Fx on the pivot arm (the first part of the pivot arm 4) from the side of the first torsion spring 3;

2 - the point of application of force F2 on the pivot arm (second part of the pivot arm 7) from the side of the second torsion spring 8;

F _kr1 -F _kr2 - the forces acting on the pivot arm from the side of the first and second torsion springs, respectively, and create torque;

F _per1 -F _per2 - the forces acting on the pivot arm from the side of the first and second torsion springs, respectively, and creating the skew moment of the pivot arm (4, 7) relative to the friction sleeve 2 and the friction sleeve 2 relative to the shaft 1;

F _N1 -F _N2 - forces acting on the pivot arm from the side of the first and second torsion springs, respectively, and press the pivot arm (4, 7) to the friction sleeve 3 and the friction sleeve 3 to the shaft.

The tension device comprises a shaft 1, the inner surface of the shaft 1.1 is mounted on a fixed base (not shown in the drawings), the flange of the shaft 1.2 has a groove of the flange of the shaft 1.3. At the end of the shaft flange 1.2 there is a slot in the shaft flange 1.4. A friction sleeve 2 is installed on the outer surface of the shaft 1.5. The slot of the shaft flange 1.4 serves to engage the first torsion spring 3 by means of the first element of the first torsion spring 3.1. The first torsion spring 3 by means of the second element of the first torsion spring 3.2 is engaged with the first part of the pivot arm 4 by the element of the first part of the pivot arm for engagement with the first torsion spring 4.1. On the flange of the first part of the pivot arm 4.2, there is a groove of the flange of the first part of the pivot arm 4.3 for installing the first torsion spring 3. The friction sleeve 2 is located between the shaft 1 and the first part of the pivot arm 4. On the outer surface of the first part of the pivot arm 4.4, there are guide grooves of the first part of the pivot arm lever 4.5. At the end of the opposite end from the flange of the first part of the pivot arm 4.2 there is an element of the first part of the pivot arm for engagement with the second torsion spring 4.6. A bearing 5 with a pulley 6 is mounted on the outer surface of the first part of the pivot arm 4.4. The second part of the pivot arm 7 is rigidly bonded to the first part of the pivot arm 4, and the two parts are positioned by the guide grooves of the first part of the pivot arm 4.5 and the guide protrusions of the second part of the pivot arm 7.1. The protrusion 1 -7.2 and the protrusion 2-7.3 of the second part of the pivot arm 7 serve to limit the rotation of the pivot arm. The eye 7.4 of the second part of the rotary lever 7 is used to indicate the degree of tension of the belt (not shown in the drawing). Element 7.5 serves to form a groove for the second torsion spring 8. The second torsion spring 8 is engaged with the pivot arm 4, 7 using the first element of the second torsion spring 8.1 through the element of the first part of the pivot arm for engagement with the second torsion spring 4.6. The second torsion spring 8 is engaged with the second element of the second torsion spring 8.2 with the plate 9 through the groove for fixing the second torsion spring 9.1. The stop 9.2 restricts the rotation of the pivot arm 4, 7 due to interaction with the protrusion 1-7.1 and the protrusion 2-7.2 of the second part of the pivot arm 7. The plate 9 is rigidly fixed to the outer surface of the shaft 1.5. The tension indicator 9.3 interacts with the eye 7.4 of the second part of the pivot arm 7. The hole of the plate 9.4 is designed to install a fastener 10 that secures the tension device to a fixed base (not shown in the drawing).

The device operates as follows.

The shaft 1 of the tensioner is mounted on a fixed base (not shown in the drawings). Adjust the nominal load on the belt (not shown in the drawings) by turning the plate 9. Align the tension indicator 9.3 of the plate 9 with the eye 7.4 of the second part of the rotary lever 7. Fix the plate 9 on a fixed base using the fastener 10. After that, the tensioner is ready to work . Moreover, if in the dynamics the load from the belt side (not shown in the drawings) on the pulley 6 increases, then the torsion springs 3, 8 of the tensioner are compressed, the eyelet 7.4 and the tension indicator 9.3 are mismatched counterclockwise (the direction of view from the side of the plate 9), the moment acting on the pivot arm (4, 7) increases and returns to its original state, not allowing the belt (not shown in the drawings) to stretch beyond the norm. When the load on the belt side decreases, the torsion springs 3, 8 open and maintain the nominal tension of the belt (not shown in the drawings) in accordance with the set values, the eye 7.4 and the tension indicator 9.3 are clockwise inconsistent. With a symmetrical design of the tensioner with two torsion springs 3, 8, the forces creating a skew moment (Fig. 9) cancel each other out, eliminating the skew of the pivot arm (4, 7) relative to the friction sleeve 2 and the friction sleeve 2 relative to the shaft 1. In this case the wear of the friction sleeve 2, shaft 1 and the rotary lever decreases, the resource of the tensioner increases.

As follows from the foregoing, the achievement of the technical result — an increase in the service life of the claimed device compared to the prototype — is achieved by introducing a second torsion spring and creating a symmetrical design of the tension device, which allows to reduce the wear of friction (friction) elements. A comparison of the parameters characterizing the claimed invention and the prototype allows us to conclude that the resource of the tensioning device increases by at least 20% relative to the prototype.

In addition to the indicated technical result achieved and the advantages of the claimed device, an additional advantage should be noted - torsion springs are 2 times less loaded compared to the prototype spring, which has a beneficial effect on the fatigue characteristics of the spring material and, ultimately, prevents the destruction of the springs during operation under cyclic loads occurring when changing the operating modes of the drive motor.

Thus, the above information proves that when implementing the claimed invention, the following conditions are met:

- a tool embodying a tensioning device in its implementation, is intended to create a preliminary load in belt transmission systems and can be used in mechanical engineering;

- for the claimed invention in the form described in the independent claim, the possibility of its implementation using the described or other means known prior to the filing date of the application has been confirmed;

- a tool embodying the claimed invention in its implementation, is able to provide the specified technical result.

Therefore, the claimed invention meets the condition of patentability "industrial applicability".

Claims (1)

A tensioning device comprising a shaft, a pivot arm mounted on the shaft rotatably about an axis, a friction sleeve mounted between the shaft and the pivot arm, a plate made with a stop to limit the rotation range of the pivot arm and rigidly mounted on the shaft, a torsion spring engaged on the shaft between the pivot arm and the plate, a bearing with a pulley mounted on the pivot arm, the center of rotation of the pivot arm being eccentrically relative to the center of rotation of the plate, this pivot arm has an eye that interacts with a tension indicator on the plate, characterized in that the pivot arm is made of two parts rigidly connected to each other, the first part of the pivot arm has a flange with a groove in which a second torsion spring is inserted between the shaft and the first part of the rotary lever, the shaft is made with a flange at one end, in which there is a slot for engagement with the second torsion spring, the shaft flange is made with a groove for installing the second torsion ruzyne, the flange portion of the first pivot arm has an element for engagement with a second torsion spring.

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