JPH0634002A - Automatic tensioner for internal combustion engine - Google Patents

Abstract

PURPOSE:To properly deep tensile strength of a driving force transmitting belt, and elongate life of the driving force transmitting belt by varying damping force of an automatic tensioner according to fluctuation of hardness of the driving force transmitting belt. CONSTITUTION:An automatic tensioner 9 of an engine 1 adjusts tensile strength of a timing belt 5. There are provided a cooling water temperature detection sensor 29 for detecting a temperature of cooling water for the engine 1, and a travel distance counter 31 for detecting a travel distance of a vehicle, on which counter 31 the engine 1 is mounted. A central processing unit 30 seizes a hardening condition of the timing belt 5, based on information from the cooling water temperature detection sensor 29 and the travel distance counter 31, and calculates optimum damping force of the automatic tensioner 9. A tensioner control unit 33 controls damping force of the automatic tensioner 9 according to the hardening condition of the timing belt 5 based on a control signal from the central processing unit 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic tensioner for adjusting the damping force of a drive transmission belt which works with a timing pulley of an internal combustion engine.

[0002]

2. Description of the Related Art Generally, the tension of an engine timing belt or the like is caused by thermal expansion and expansion or contraction of the timing belt itself or each portion in which the timing belt is stretched.
It is known that the timing belt changes with time. The change in the tension of the timing belt causes breakage of the timing belt or skipping of the timing belt, resulting in a hindrance to the operation of the engine. Therefore,
In order to suppress such a problem due to the change in the tension of the timing belt, various auto tensioners that maintain the tension of the timing belt at an appropriate value have been proposed. For example, the number of revolutions of the engine and the temperature of the engine are detected, and the belt tension is adjusted based on the result of the detection (actual measurement of the actual opening 1-1.
No. 49052), or the one in which the vibration of the oscillating body is attenuated by the damping action of oil to keep the tension of the belt at an appropriate value (Actual Kaihei 1-92549).

[0003]

By the way, generally, a drive transmission belt such as a timing belt of an engine is hardened due to deterioration over time, a traveling distance, an ambient temperature in the engine, etc., and travels as shown in FIG. 9 (A). It is known that it hardens as the time (distance) increases (solid line 50) and further hardens as the atmospheric temperature decreases (dashed line 51). Further, regarding the relationship between the hardness of the belt, the belt tension, and the damping force, as shown in FIG. 9B, when the damping force is kept constant, the tension of the belt increases as the belt hardens. I know it experimentally.

However, in all of the above-mentioned auto tensioners, the damping force is set to be constant, and the dynamic tension increase due to the hardening of the belt has not been taken into consideration. That is, since the damping force is set to be constant, the belt tension is increased due to the hardening of the belt, and as a result, the belt life is shortened.

The present invention has been made in order to solve the above problems, and changes the damping force of the auto tensioner in accordance with the change in hardness of the drive transmission belt to maintain the tension of the drive transmission belt appropriately. An object of the present invention is to provide an autotensioner for an internal combustion engine that can extend the belt life.

[0006]

The invention according to claim 1 is
In an automatic tensioner for an internal combustion engine that adjusts the tension of a drive transmission belt, a damping force adjusting means that can change the damping force of the automatic tensioner, a detecting means that detects the operating condition of the internal combustion engine, and detection information from this detecting means. Based on the detection information processing means for determining the curing state of the drive transmission belt based on the above, and the processing information from the detection information processing means, the damping force of the auto tensioner is reduced according to the curing of the drive transmission belt. And a control means for controlling the damping force adjusting means.

According to the second aspect of the present invention, the drive transmission belt is hardened by the decrease of the ambient temperature in the internal combustion engine, and by detecting the hardened state of the drive transmission belt with the decrease of the ambient temperature, the automatic The damping force of the tensioner is reduced according to the hardening of the drive belt.

According to the third aspect of the present invention, the drive transmission belt is hardened due to its deterioration. By detecting the hardened state of the drive transmission belt due to the deterioration, the damping force of the automatic tensioner is applied to the drive belt. It has been reduced in accordance with the hardening of.

According to a fourth aspect of the present invention, the cured state of the drive transmission belt is detected by the traveling distance of the vehicle in which the internal combustion engine is mounted.

According to a fifth aspect of the present invention, there is provided an automatic tensioner for an internal combustion engine, which adjusts tension of a drive transmission belt,
The auto tensioner includes a base portion and a main body portion that is supported so as to be displaceable relative to the base portion and that applies tension to the drive transmission belt. An electromagnet is provided on the base portion and the main body portion is provided. A magnetic body is provided on the magnetic disk, and the damping force adjusting means is configured so that the electromagnet and the magnetic body suppress the relative movement of the main body with respect to the base due to the magnetic force according to the energization of the electromagnet.

According to a sixth aspect of the present invention, there is provided means for detecting an increase in the ambient temperature in the internal combustion engine, and correcting the damping force of the autotensioner in accordance with the increase in the ambient temperature.

[0012]

According to the first aspect of the invention, the belt tension is adjusted by reducing the damping force of the auto tensioner in accordance with the hardening of the drive transmission belt.

According to the second aspect of the present invention, the hardening of the drive transmission belt is caused by the decrease of the atmospheric temperature in the internal combustion engine, and the damping force of the auto tensioner is reduced in accordance with the decrease of the atmospheric temperature.

According to the third aspect of the present invention, the hardening of the drive transmission belt is caused by the deterioration of the drive transmission belt.
The damping force of the auto tensioner is reduced according to the deterioration state of the drive belt.

According to the invention described in claim 4, the deterioration state of the drive transmission belt is detected from the traveling distance of the vehicle in which the internal combustion engine is mounted.

According to the invention described in claim 5, the damping force of the autotensioner is controlled by changing the magnetizing force of the electromagnet.

According to the invention described in claim 6, the increase of the damping force with the increase of the ambient temperature is caused by the increase in the damping force of the invention described in claim 5.
It is corrected by changing the described electromagnetic force.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an engine to which an auto tensioner according to the present invention is applied.

A timing pulley 2 fixed to the end of the exhaust camshaft and a timing pulley 3 fixed to the end of the intake camshaft are disposed on the upper side surface of the engine 1, and the lower side surface of the engine 1 is provided. Is provided with a crankshaft timing pulley 4 provided at the end of the crankshaft. A timing belt 5 is stretched around the timing pulleys 2 and 3 and the crankshaft timing pulley 4. The timing belt 5 is
When the crankshaft timing pulley 4 is rotationally driven, the crankshaft timing pulley 4 moves in the direction of arrow 6 in FIG. 1 to interlock the timing pulleys 2 and 3. Belt idlers 7 and 8 are provided between the timing pulleys 2 and 3 and the crankshaft timing pulley 4. Then, the timing pulley 2 and the belt idler 7
The autotensioner 9 according to the present invention is disposed between and.

Here, the structure of the automatic tensioner 9 will be described with reference to FIG.

The automatic tensioner 9 comprises a base 10 and a tensioner body 11 which is mounted on the base 10 and is rotatably inserted into the base 10.

The base 10 includes, for example, a disk-shaped base 12 and
An aerial cylinder 13 joined to the center of the base 12, and an annular electromagnet 14 disposed on the base 12 along the outer periphery of the aerial cylinder 13 and magnetically controlled by a tensioner control device 33 described later. Is equipped with this base 10
Is fixed to a block 16 provided in the engine 1 by a bolt 15 via the aerial columnar portion 13.

The tensioner body 11 has an annular case portion 19 having a double wall structure of an outer case 17 and an inner case 18, and an arm 20 joined to the outer peripheral surface of the outer case 17 of the case portion 19. A pulley 22 is rotatably attached to the tip of the arm 20 by a bolt 21, and the case portion 19 is a hollow cylinder portion 13 of the base 10.
It is mounted on the base 10 by being rotatably inserted thereinto. Outer case 17 and inner case 1 of the case portion 19
A space 23 is formed between the space 8 and the space 8.
Inside, an air columnar push rod 24 made of a magnetic material is fitted to the outer circumference of the inner case 18. The push rod 24 moves relative to the inner case 18 in the axial direction thereof, while the engaging means (not shown) causes the inner case 1 to move.
It is configured so that it cannot rotate relative to the No. 8. A flange 25 is formed at the end of the push rod on the side of the base 12, and a spring 26 is fixed to the opposite end. The push rod 24 is biased by the spring 26 in a direction away from the base 12. As a result, the electromagnet 14
Is magnetized, the push rod 24 is moved by being attracted to the electromagnet 14, and the flange portion 25 and the electromagnet 14 are brought into contact with each other. On the other hand, when the electromagnet 14 is not magnetized, the urging force of the spring 26 causes It is configured to be separated from the electromagnet 14.

The tensioner main body 1 thus constructed
1 is integrally rotated with respect to the base 10 by a spring 27 provided in the space 23 of the case 19, and
The pulley 22 presses the timing belt 5 in the direction of the arrow 28 in FIG. 1 to apply tension to the timing belt 5, while the electromagnet 14 is magnetized.
The rotation with respect to 0 is suppressed. Then, the electromagnet 14 and the push rod 24 constitute a damping adjusting means.

On the other hand, a cooling water temperature detecting sensor 29 is provided in a cooling water passage (not shown) of the engine 1, and the water temperature is detected by a control signal from a central processing unit 30 (hereinafter referred to as CPU), and the detection thereof is performed. The result is output to the CPU 30. Also, on the vehicle body not shown in the figure,
A traveling distance counter 31 is provided, and the traveling distance data is output to the CPU 30. CPU
At 30, the hardened state of the timing belt 5 is determined based on the traveling distance data from the traveling distance counter 31 and the water temperature data from the cooling water temperature detection sensor 29.
Functions as detection information processing means. Based on this determination, a control signal is output to the tensioner control device 33 so as to set the optimum damping force on the timing belt 5. The tensioner control device 33 controls the damping force of the auto tensioner 9 according to a control signal from the CPU 30.

Next, the operation of the automatic tensioner 9 having the above structure will be described.

The damping force of the automatic tensioner 9 is adjusted, for example, every time the vehicle is started. When the vehicle is started, the CPU
When the traveling distance counter 31 outputs the accumulated traveling distance data by the control signal from the control signal 30, the cooling water temperature detection sensor 29 detects the water temperature value and outputs the detected data. Each of the above data is input to the CPU 30 to calculate the value of the current flowing to the auto tensioner 9. In the tensioner control device 33, the above C
The auto tensioner 9 according to the calculated data of the PU 30
Control the value of the energizing current to. In other words, auto tensioner 9
The damping force is controlled by increasing or decreasing the value of the current passed through the electromagnet 14.

For example, when the auto tensioner 9 is not energized or the energization current value is low, the electromagnet 14 of the auto tensioner 9 is not magnetized (the magnetic force is weak), so that the tensioner body 11 is Base 1
It can be easily rotated with respect to zero. Accordingly, the pulley 22 is pressed against the timing belt 5 by the spring 27 of the tensioner main body 11 and an appropriate tension is applied to the timing belt 5, while the tensioner main body 11 is swung in accordance with the swing of the timing belt 5. That is, the damping force is low.

On the other hand, when the auto tensioner 9 is energized or the energization current value is high, the electromagnet 14 is magnetized and the push rod 24 is attracted to the electromagnet 14. That is, the force with which the push rod 24 is attracted to the electromagnet 14 becomes a frictional force against the rotation of the tensioner main body 11, and the rotation of the tensioner main body 11 with respect to the base 10 is suppressed. As a result, the state in which the pulley 22 presses the timing belt 5 is maintained, and the timing belt 5
The swinging of the is suppressed by the tensioner main body 11. That is, the damping force is high.

As described above, the damping force is increased by increasing the value of the current passed through the electromagnet 14 of the auto tensioner 9. That is, the electromagnet 14
It is possible to change the attraction force of the electromagnet 14 by increasing or decreasing the value of the energizing current to the electromagnet 14, and as a result, to set the damping force variously.

Next, a method of setting the value of the energizing current of the auto tensioner 9 having the above structure will be described with reference to FIGS. 3 and 4.

Since the damping force of the auto tensioner 9 can be changed in proportion to the value of the electric current supplied to the electromagnet 14 of the auto tensioner 9 as described above, the traveling distance counter 31 and the cooling water temperature detecting sensor 29 are described. Based on the detected value from, the CPU 30 sets the optimum energizing current value for the hardening state of the timing belt 5 to set the optimum damping force.

First, when the travel distance data X is input in step S ₁ , the energization current classification is determined from the travel distance data X in step S ₂ . That is, as shown in FIG. 4 (A), in the CPU 30, the energizing current for giving the optimum damping force to the cured state of the timing belt 5 is assumed, assuming the cured state of the timing belt 5 according to the accumulated traveling distance. The value is preset. Specifically, the energizing current value is set to decrease as the cumulative traveling distance increases. In other words, the hardening of the timing belt progresses as the traveling distance increases, so that the value of the energizing current is lowered to reduce the damping force. When the energized current section is determined, the energized current value I _X of the traveling distance corresponding to the energized current section is determined in step S ₃ .

From the above, the energizing current value I depending on the traveling distance
_{When x} is determined, the process then proceeds to step S ₄ for obtaining the energizing current value depending on the cooling water temperature. In step S ₄ ,
When the cooling water temperature data Tw is input, the energization current classification is determined from the cooling water temperature data Tw in step S ₅ .
That is, as in the case of the traveling distance described above, as shown in FIG. 4B, the CPU 30 assumes the cured state of the timing belt 5 according to the cooling water temperature, and is optimal for the cured state of the timing belt 5. An energizing current value for applying the damping force is preset. Specifically, the energization current value is set to decrease as the water temperature decreases.
That is, the hardening of the timing belt 5 progresses as the atmospheric temperature in the engine 1 decreases, so that the value of the energizing current is decreased to reduce the damping force.
When the energization current classification is determined, the energization current value I _TW according to the cooling water temperature corresponding to the energization current classification is determined in step S ₆ .

When the energizing current value I _{TW depending on the} cooling water temperature is determined, the process _proceeds to step S ₇ . Step S ₇
Then, the energizing current value I _X according to the traveling distance and the energizing current value I _TW according to the cooling water temperature are added, and the auto tensioner 9
The energization current value I to be energized is calculated, and this flowchart is ended.

When the energizing current value I to the auto tensioner 9 is calculated by the CPU 30, the CPU 30 outputs a control signal for controlling the energizing current value to the tensioner control device 33. The tensioner control device 33 controls the value of the energizing current to the auto tensioner 9 based on the control signal from the CPU 30.

Thus, the tension of the timing belt is kept constant by grasping the hardening state of the timing belt and setting the optimum damping force according to the hardening state of the timing belt 5 as shown in FIG. It will be possible.

In the above embodiment, the running distance counter 31 and the cooling water temperature detecting sensor 29 are provided, and the damping force is taken into consideration in consideration of the hardening of the timing belt 5 due to the deterioration of the timing belt 5 and the hardening of the timing belt 5 due to the ambient temperature. Is set, the cured state of the timing belt 5 can be grasped more accurately, and the tension of the timing belt 5 can be set to an optimum value. Further, by changing the value of the current supplied to the auto tensioner 9 and changing the attraction force (friction force) between the push rod 24 and the electromagnet 14, the damping force of the auto tensioner 9 can be adjusted, which is simple. There is also an advantage that the damping force can be adjusted more finely with the configuration.

When setting the energizing current value in the CPU 30, control may be performed so as to correct the increase in the damping force due to the ambient temperature. That is, in the above embodiment, when the tensioner body 11 is made of aluminum or the like,
As the ambient temperature rises, aluminum tends to expand, and rotation with respect to the base 10 tends to be suppressed. That is, as shown in FIG. 6 (A), the damping force rises as the ambient temperature rises. Such an increase in damping force is as shown in FIGS. 6 (B) and 6 (C). This leads to an increase in belt tension, resulting in a shorter belt life. Therefore, as shown in FIG. 7, the increase in the damping force (a in FIG. 7) due to the rise in the ambient temperature is corrected by setting the conduction current value low (c in FIG. 7), and as a result, the damping force is increased. The increase in the belt tension (b in FIG. 7) is suppressed and the belt tension is kept constant (d in FIG. 7).

Further, the engine speed may be detected and the damping force may be changed according to the engine speed. This is because, as shown in FIG. 8, when the engine is operated at a low speed while the damping force is kept constant (e in FIG. 8), the runout amount of the timing belt increases (see FIG. 8).
F), it will cause vibration and noise of the vehicle. In this case, the damping force is increased (g in FIG. 8) by setting the energization current value high in the low rotation region of the engine, and this increase of the damping force causes an increase in the dynamic tension of the timing belt. As a result, the shake amount is reduced (h in FIG. 8). If you do this,
It is possible to suppress problems such as vibration and noise in the low engine speed region.

[0041]

As described above, according to the present invention, in the automatic tensioner of the internal combustion engine for adjusting the tension of the drive transmission belt, the damping force adjusting means for changing the damping force of the automatic tensioner and the operation of the internal combustion engine. Detection means for detecting the situation, detection information processing means for determining the curing state of the drive transmission belt based on the detection information from the detection means, and detection information processing means for the drive transmission belt based on the processing information from the detection information processing means. Since the control means for controlling the damping force adjusting means is provided so as to reduce the damping force of the auto tensioner according to the curing, the damping force of the auto tensioner is optimally set with respect to the hardness change of the drive transmission belt. As a result, the tension of the drive transmission belt can be maintained properly, and as a result, the life of the drive belt can be shortened. It becomes possible bus.

[Brief description of drawings]

FIG. 1 is a schematic side view showing an engine to which the present invention is applied.

FIG. 2 is a cross-sectional view taken along the line I-I in FIG. 1, showing the auto tensioner according to the present invention.

FIG. 3 is a flow chart showing a procedure for setting an energizing current value related to setting a damping force.

FIG. 4A is a graph showing an energization current value with respect to a traveling distance, and FIG. 4B is a graph showing an energization current value with respect to a water temperature.

FIG. 5 is a graph showing the effect of the present invention.

6A is a graph showing the relationship between ambient temperature and damping force, FIG. 6B is a graph showing the relationship between damping force and belt tension, and FIG. 6C is a graph showing belt tension and belt life. It is a graph which shows a relationship.

FIG. 7 is a graph showing the relationship between the damping force, the belt tension, and the ambient temperature of the auto tensioner according to the present invention.

FIG. 8 is a graph showing the relationship between the engine speed, the amount of run-out of the timing belt, and the damping force of the auto tensioner.

FIG. 9A is a graph showing the relationship between running time, temperature, and belt hardness of a timing belt, and FIG. 9B is a graph showing damping force, belt tension, and belt hardness of a timing belt in a conventional auto tensioner. It is a graph which shows a relationship.

[Explanation of symbols]

 1 Engine 5 Timing Belt 9 Auto Tensioner 29 Cooling Water Temperature Detection Sensor 30 Central Processing Unit 31 Traveling Distance Counter 33 Tensioner Control Device

Claims (6)

[Claims] 1. An automatic tensioner for an internal combustion engine, which adjusts the tension of a drive transmission belt, comprising: damping force adjusting means capable of changing the damping force of the automatic tensioner;
Based on the detection means for detecting the operating condition of the internal combustion engine, the detection information processing means for determining the curing state of the drive transmission belt based on the detection information from the detection means, and the processing information from the detection information processing means, An automatic tensioner for an internal combustion engine, comprising: a control unit that controls the damping force adjusting unit so as to reduce the damping force of the automatic tensioner according to the hardening of the drive transmission belt. 2. The drive transmission belt is hardened by lowering the ambient temperature in the internal combustion engine, and the damping force of the automatic tensioner is detected by detecting the hardened state of the drive transmission belt due to the lowering of the ambient temperature. An autotensioner for an internal combustion engine according to claim 1, wherein the autotensioner is reduced in accordance with the hardening of the drive belt. 3. The hardening of the drive transmission belt is due to its deterioration, and the damping force of the auto tensioner is reduced according to the hardening of the drive belt by detecting the hardening state of the drive transmission belt due to the deterioration. The autotensioner for an internal combustion engine according to claim 1, wherein 4. The automatic tensioner for an internal combustion engine according to claim 3, wherein the hardened state of the drive transmission belt is detected by the traveling distance of a vehicle in which the internal combustion engine is mounted. 5. An autotensioner for an internal combustion engine, which adjusts the tension of a drive transmission belt, wherein the autotensioner is supported by a base and a relative displacement with respect to the base.
The drive transmission belt is provided with a main body for applying a tension, and the base is provided with an electromagnet, and the main body is provided with a magnetic body, and the electromagnet and the magnetic body provide a magnetic force according to energization of the electromagnet. The automatic tensioner for an internal combustion engine according to any one of claims 1 to 4, wherein the damping force adjusting means is configured to suppress relative movement of the main body with respect to the base. 6. The internal combustion engine according to claim 5, further comprising means for detecting an increase in the ambient temperature in the internal combustion engine and correcting the damping force of the autotensioner in accordance with the increase in the ambient temperature. Institutional auto tensioner.