JP2001241521A - Belt tensioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a belt tensioner which is easy to set belt tension, gets a flat and linear characteristic and absorbs effectively and reduce vibrations generated on belt and reduce them. SOLUTION: The working cylinder 8 equipped with a belt tension pulley 4 is inserted into a stationary cylinder 7 with free flexibility in axial direction. Between the cylinder 7 and 8, an oil damper 15 to reduce expansion and contraction works of both cylinder, and, the coil spring 18 to make power to extendable direction from holding condition of initial deflection, are set on the same axis. The belt tension pulley 4 is pushed on the belt 3 through the oil damper 15 and the coil spring 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt tensioner for reducing the vibration of a belt in addition to absorbing the elongation of the belt accompanying the driving of various machines such as a driving belt for power transmission and a belt conveyor.

[0002]

2. Description of the Related Art As this type of belt tensioner a conventionally used, as shown in FIG.
Square pipe-shaped inner cylinder b inserted into each other with a phase difference of 5 degrees
Elastic rods d made of a material such as rubber are sandwiched between the four corners between the outer cylinder c and the outer cylinder c, and the outer cylinder c is laid horizontally and fixed at a predetermined position, and the support arm e is extended from the end of the inner cylinder b. A tension pulley f is rotatably attached to the tip.

[0003] A spring force is applied while deforming the elastic rod d by applying a relative displacement in the rotational direction between the inner cylinder b and the outer cylinder c. The tension pulley f is pressed against belts g of various machines to absorb the elongation, and the vibration of the belt g is suppressed and reduced by the internal friction between the inner and outer cylinders b and c and the elastic rod d. It has been known.

[0004]

However, in the belt tensioner a conventionally known, the spring characteristic of the belt tensioner a is obtained by utilizing the deformation of the elastic rod d as described above. Therefore, the spring characteristic becomes a non-linear characteristic, the torque change with respect to the swing displacement of the support arm e is large, and it is difficult to set the tension of the belt g.

In addition, since the inner and outer cylinders b and c and the elastic rod d constituting the spring mechanism are located at the center of the swing of the support arm e having the tension pulley f,
The amount of deformation of the elastic rod d is small with respect to the amplitude of the vibrating belt g, and the buffering effect due to the internal friction between the inner and outer cylinders b and c and the elastic rod d alone is insufficient to reduce the vibration of the belt g. It cannot be suppressed sufficiently.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to set a belt tension as flat and linear as possible to effectively reduce vibration generated in the belt in addition to absorbing belt elongation. It is to provide a tensioner.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is to insert a working cylinder equipped with a tension pulley into and out of a holding cylinder so as to extend and contract in the axial direction. A hydraulic damper, which provides a damping effect on the expansion and contraction of the two, and a coil spring, which applies a force in the direction of extension in a state where initial deflection is applied, are interposed coaxially with each other. By pressing the tension pulley through the belt against the belt.

[0008] That is, with the above configuration, the tension applied to the belt from the tension pulley is:
It is uniquely determined by the spring characteristics of the coil spring incorporated in the belt tensioner, and it is possible to easily set the tension of the belt with flat and linear characteristics as much as possible, so that the elongation of the belt can be effectively absorbed. .

In addition, in response to the amplitude of the vibrating belt, a hydraulic damper disposed coaxially with the coil spring expands and contracts to absorb the vibration of the belt, and the vibration generated in the belt is reduced. Can be effectively suppressed and reduced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A belt tensioner according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows various machines such as a drive belt for transmitting power and a belt conveyor for carrying luggage, which presses a belt 3 which is stretched from one pulley 1 to another pulley 2 from the outside, thereby forming a belt 3. 1 shows an application example of a belt tensioner 5 according to the present invention including a tension pulley 4 for absorbing elongation and reducing vibration.

That is, the belt tensioner 5 is
As shown in FIG. 2, a main body portion that slides and inserts an operating cylinder 8 slidably into a holding cylinder 7 on which a mounting portion 6 is formed, and that telescopically expands and contracts the holding cylinder 7 and the operating cylinder 8. 9
And attached to a predetermined site through the mounting portion 6 of the holding cylinder 7.

From the upper end of the operating cylinder 8 that slides with respect to the holding cylinder 7, a support arm 10 further extends in the axial direction and extends outward. A tension pulley 4 is rotatably supported via a horizontal shaft 11.

A pin 12 is inserted from the holding cylinder 7 into a long groove 13 formed in the side surface of the operating cylinder 8 so that these pins 1
The rotation preventing mechanism 14 is configured while allowing the holding cylinder 7 and the operating cylinder 8 to expand and contract in the axial direction by fitting the 2 and the long groove 13,
The rotation preventing mechanism 14 enables the tension pulley 4 to be moved only in and out of the belt 3 without changing its direction.

The holding cylinder 7 and the operating cylinder 8 which constitute the main body 9
The hydraulic damper 15 is housed in the inside of the cylinder while maintaining the coaxial state, and both ends of the hydraulic damper 15 are attached to the holding cylinder 7 and the operating cylinder 8 with screws 16 and 17, and the expansion and contraction of the holding cylinder 7 and the operating cylinder 8 The damping action is applied while the hydraulic damper 15 is extended and contracted in conjunction with the operation.

A coil spring 18 surrounding the hydraulic damper 15 and having a predetermined spring constant as shown in FIG. The tension pulley 4 is pressed against the lower surface of the belt 3 of the applied machine while the operating cylinder 8 is pushed out of the holding cylinder 7 by the spring force of the coil spring 18.

As a result, the tension applied to the belt 3 of the applied machine through the tension pulley 4 of the belt tensioner 5 is uniquely determined by the spring characteristics of the coil spring 18 incorporated in the belt tensioner 5, so that the spring constant is reduced. By increasing the initial deflection, a linear or flat and linear spring characteristic can be obtained. Therefore, the elongation of the belt 3 can be effectively absorbed by the stable tension setting.

In addition, when the vibration of the belt 3 is dealt with, the hydraulic damper 15 arranged coaxially with the coil spring 18 expands and contracts to absorb the vibration of the belt 3. The generated vibration is effectively absorbed and reduced.

As described above, in the belt tensioner 5 shown in FIGS. 1 and 2, the holding cylinder 7 having the mounting portion 6 is formed in a bottomed cylindrical shape, and the hydraulic damper 15 and the coil spring The tension pulley 4 is pressed from the outside to the outside of the belt 3 by the spring force of the coil spring 18 so as to absorb the elongation of the belt 3 and reduce the vibration.

On the other hand, in the belt tensioner 5a shown in FIGS. 4 and 5, the operating cylinder 8a is slidably inserted through the holding cylinder 7a, which is the main body 9a, and the hydraulic damper 15 is in the inverted state. And a holding cylinder 7a whose base end is formed from a long groove 13a drilled on the side surface of the
And was interposed between the holding cylinder 7a and the operating cylinder 8a.

Then, a coil spring 18 is interposed around the hydraulic damper 15 and the working cylinder 8a,
The tension pulley 4 is pressed against the outer surface of the belt 3 from inside by the spring force of the coil spring 18, contrary to the belt tensioner 5 in FIGS.
The belt 3 is designed to absorb elongation and reduce vibration.

As described above, even in the belt tensioner 5a shown in FIGS. 4 and 5, the hydraulic damper 15 and the coil spring 18 are interlocked with each other with the operation of the operating cylinder 8a. The belt 3 is made to have a stable tension by linear and flat spring characteristics by reducing the
In addition, the hydraulic damper 15 can cope with the vibration of the belt 3 and effectively reduce the vibration.

The above-mentioned belt tensioners 5, 5
a, holding cylinders 7, 9 constituting each body portion 9, 9a;
6 and the working cylinders 8 and 8a are formed to have a square cross section as shown in FIG.
Non-rotating mechanism 14, 14a between 7a and working cylinders 8, 8a
There is no need to do it.

[0024]

As described above, according to the first aspect of the present invention, the operating cylinder equipped with the tension pulley is inserted into the holding cylinder so as to be extendable and contractible in the axial direction, and the holding cylinder and the operating cylinder are inserted. The tension is achieved by interposing a hydraulic damper, which provides a damping effect on the expansion and contraction of both members, and a coil spring, which applies a force in the direction of extension with the initial flexure, coaxially with each other. Since the tension applied to the belt of the applicable machine through the pulley is uniquely determined by the spring characteristics of the coil spring incorporated in the belt tensioner, a linear or flat linear spring can be obtained by reducing the spring constant and increasing the initial deflection. Characteristics can be obtained, so that the elongation of the belt can be effectively absorbed by the stable tension setting.

In addition, in order to cope with the belt vibration, the hydraulic damper arranged coaxially with the coil spring expands and contracts to absorb the belt vibration. Not only can effectively absorb and reduce the vibrations that occur, but also provide a vibration damping effect by placing the hydraulic damper and coil spring in parallel, resulting in reduced belt load fluctuations. This has the advantage of extending the life of the belt.

[Brief description of the drawings]

FIG. 1 is a front view schematically showing one use mode of a belt tensioner according to the present invention.

FIG. 2 is a longitudinal sectional front view of a main part showing a specific structural example of a belt tensioner used in the above.

FIG. 3 is a spring characteristic diagram showing a relationship between a compression amount and a spring force of a coil spring incorporated in the belt tensioner.

FIG. 4 is a front view schematically showing another usage of the belt tensioner according to the present invention.

FIG. 5 is a longitudinal sectional front view of a main part showing a specific structural example of a belt tensioner used in FIG. 4;

FIG. 6 is a cross-sectional plan view of a main part showing a modified example of the belt tensioner according to the present invention described above.

FIG. 7 is a front view schematically showing the manner of use of a conventionally known belt tensioner.

[Explanation of symbols]

 Reference Signs List 3 Belt 4 Tension pulley 5 Belt tensioner 6 Attachment part 7 Holding cylinder 8 Working cylinder 9 Main body 10 Support arm 14 Non-rotating mechanism 15 Hydraulic damper 18 Coil spring

Claims (1)

[Claims] 1. An operating cylinder equipped with a tension pulley is inserted into a holding cylinder so as to be extendable and contractible in the axial direction, and a damping action is provided between the holding cylinder and the operating cylinder with respect to the expansion and contraction of the two. A belt tensioner comprising a hydraulic damper and a coil spring for applying a force in an extending direction with an initial flexure interposed therebetween while maintaining the same coaxial state.