JPH0712155A - Wet type friction gearing damage preventing method and device therefor - Google Patents

Abstract

PURPOSE:To grasp the temperature state of a clutch accurately so as to prevent damage caused by heating. CONSTITUTION:The rotating speed of the input shaft 12 of a clutch 10 is detected by an input shaft sensor 15, the rotating speed of an output shaft 16 is detected by an output shaft sensor 17, the transmission torque of the output shaft 16 is detected by a torque sensor 19, the temperature of engine oil flowing into the clutch 10 is detected by an oil temperature sensor 34, and these detection signals are inputted into an arithmetic processing unit 40. The contact part temperature computing element 44 of the arithmetic processing unit 40 computes the temperature of a clutch plate 18 on the basis of the detection signals and inputs it into a comparing part 50. The comparing part 50 compares the computed temperature with the reference value and sounds an alarm in the case of being the reference value or more. The temperature computed by the contact part temperature computing element 44 is inputted into an inner-outer peripheral temperature computing element 48. The inner-outer peripheral temperature computing element 48 computes the inner-outer peripheral temperature difference of the clutch plate 18 and outputs it to the comparing part 50, and the comparing part 50 sounds an alarm when the inner-outer peripheral temperature difference of the clutch plate 18 is the reference value or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing damage to a friction transmission device for transmitting power by frictionally engaging a driving side and a moving side, and particularly to a transmission of a construction machine or a clutch of a retarder. As described above, the present invention relates to a method and an apparatus for preventing damage to a wet friction transmission device in which a driving-side rotating body and a sliding-side rotating body are used in a sliding state and a cooling fluid is supplied to a contact portion between the two.

[0002]

2. Description of the Related Art A friction clutch can change the power transmission rate by changing the contact pressure between the driving side rotating body and the sliding side rotating body, and can arbitrarily change the output on the driven side. Various machines such as a power divider transmission (power divider) that splits and outputs the output of the engine in order to obtain the power of the retarder used during slopes, the transmission of construction machinery, or the water discharge pump of a fire engine and running power, Widely used for power transmission and braking of devices.

By the way, during the inching operation of the transmission, the retarder, the power divider, etc., the clutch is always held in a slipping state, so that the frictional heat causes a contact portion between the driving side rotating body and the sliding side rotating body of the clutch. Heats up to a high temperature, the plate that is the clutch plate of the clutch is deformed due to thermal stress, and the disk surface is damaged by heat.
Deterioration due to heat occurs.

The heat damage of the clutch can be determined mainly by the temperature of the contact portion where the driving side rotating body and the sliding side rotating body are in contact with each other. Further, when the rotating body is constituted by a plate-like plate (disc) like a multi-plate clutch,
Damage is caused not only by the plate temperature T _P but also by the difference ΔT _P between the temperature on the inner peripheral side and the temperature on the outer peripheral side of the plate. That is, as shown in FIG. 4, when the plate temperature T _P exceeds the allowable value, heat deterioration of the plate surface, seizure, transfer,
Damage such as peeling off of adhesive parts such as liner occurs. Further, when the temperature difference ΔT _P between the inner peripheral side and the outer peripheral side of the plate exceeds the allowable value, the plate is deformed by bending like a plate due to the difference in thermal expansion, causing uneven wear, or the plate of the other side. It may damage the (disc).

Therefore, in such a transmission device utilizing sliding friction, the rotary contact portion is cooled by lubricating oil (engine oil) as a coolant, and
In order to handle and operate properly, generally, an instruction manual is prepared, and an appropriate usage method in the instruction manual (for example, in the case of a retarder, continuous slip that can be used according to the load such as downhill slope and vehicle weight) Time or downhill distance) is explained.

FIG. 5 shows a part of the operation manual for the retarder and shows how to obtain the vehicle speed when descending a slope. That is, for example, the downhill distance is 1500 m, the running resistance is -11% (gradient resistance -13%, rolling resistance +2).
%), The vehicle weight is 32 tons (total vehicle weight is about 62%).
Ton), the graph is traced as A → B → C → D to show that the retarder should be used so that the traveling speed of the vehicle is 40 km / h. The usage conditions are specified by the explanation.

Further, at the oil outlet of the clutch, the temperature of the lubricating oil flowing out from the clutch is measured, and when this oil temperature exceeds a permissible value, that fact is displayed by a red lamp or an alarm buzzer sounds. The attention signal is generated.

[0008]

However, in the method of defining the continuous slip time or the downhill distance in accordance with the load in the above instruction manual, the accuracy of the load is determined by the operator. However, it cannot protect against reckless handling that ignores the instruction manual.

On the other hand, in the method of detecting the outlet temperature of the lubricating oil and giving a warning to the operator, when the temperature of the lubricating oil flowing into the clutch is low, the temperature rise of the lubricating oil is large due to heat generation at the contact portion of the clutch, Although there is a considerable temperature difference between the clutch inflow temperature and the outflow temperature of the oil and the clutch is damaged, the temperature of the lubricating oil itself flowing out from the clutch is not so high because the inflow temperature is low, You might miss the damage to the clutch. Especially when the clutch is suddenly slipped and used under high load immediately after starting, it is easy to miss the damage to the clutch.

The present invention has been made in order to solve the above-mentioned drawbacks of the prior art. It is possible to accurately grasp the temperature condition of the rotary contact portion and prevent damage due to heat generation. And its device.

[0011]

The first method of preventing damage to a wet friction transmission device according to the present invention is to change the contact pressure of the contact portion between the driving side rotating body and the sliding side rotating body to change the power transmission rate. In the method of preventing damage to a wet friction transmission device, the rotational speed of the driving side rotating body, the rotating speed of the moving side rotating body, the inlet temperature of the fluid for cooling the contact portion, and the torque capacity of the contact portion are used. The temperature of the contact portion is obtained, and a caution signal is output when the temperature is equal to or higher than a reference value. The temperature of the contact portion may be a temperature difference between two points in the contact portion in different radial directions.

The second method of preventing damage to a wet friction transmission device according to the present invention is to change the contact pressure of the contact portion between the driving side rotating body and the sliding side rotating body to change the power transmission rate. In the damage prevention method, the rotation speed of the drive-side rotating body, the rotation speed of the sliding-side rotating body, the inlet temperature of the fluid for cooling the contact portion, and the contact pressure of the contact portion are used to determine the temperature of the contact portion. Is obtained and a caution signal is output when this temperature is equal to or higher than a reference value.

A third method of preventing damage to a wet friction transmission device according to the present invention is a wet friction system which changes a contact pressure at a contact portion between a driving side rotating body and a sliding side rotating body to change a power transmission rate. In a method for preventing damage to a transmission device, a rotation speed of the drive-side rotating body, a rotation speed of the moving-side rotating body, an inlet temperature of a fluid for cooling a contact portion, and a control valve for controlling a contact pressure of the contact portion. It is characterized in that the temperature of the contact portion is obtained from the command current to and a caution signal is output when the temperature is equal to or higher than a reference value.

A damage prevention device for a wet friction transmission device for carrying out the above first damage prevention method is a wet type device that changes a contact pressure at a contact portion between a driving side rotating body and a sliding side rotating body to change a power transmission rate. In a damage preventing device for a friction transmission device, a drive speed sensor for measuring the rotation speed of the drive rotating body,
A driven side speed sensor that measures the rotation speed of the moving side rotating body, a temperature sensor that measures the inlet temperature of the fluid that cools the contact portion, a torque sensor that measures the torque of the output shaft, and the drive side speed sensor. Based on the detection signals of the moving speed sensor, the temperature sensor, and the torque sensor, the contact portion temperature calculation unit that obtains the temperature of the contact portion, and the temperature of the contact portion obtained by the contact portion temperature calculation unit, It is configured to have a comparison unit that compares the temperature with a predetermined allowable temperature and outputs an operation signal to an alarm device.

The damage prevention device for carrying out the second damage prevention method is a wet friction transmission device for changing the power transmission rate by changing the contact pressure at the contact portion between the driving side rotating body and the sliding side rotating body. In the damage prevention device, the drive-side speed sensor that measures the rotation speed of the drive-side rotating body, the driven-side speed sensor that measures the rotating speed of the moving-side rotating body, and the inlet temperature of the fluid that cools the contact part A temperature sensor for measuring, a hydraulic sensor for measuring the hydraulic pressure for pressurizing the contact portion, a drive side speed sensor, a moving side speed sensor, the temperature sensor, and a detection signal of the hydraulic sensor based on the detection signal of the contact portion. Comparing the temperature of the contact portion to calculate the temperature and the temperature of the contact portion obtained by the contact portion temperature calculation portion with a predetermined allowable temperature,
And a comparator for outputting an actuation signal to the alarm device.

The damage prevention device for carrying out the third damage prevention method is a wet friction transmission device for changing the power transmission rate by changing the contact pressure of the contact portion between the driving side rotating body and the sliding side rotating body. In the damage prevention device, the drive-side speed sensor that measures the rotation speed of the drive-side rotating body, the driven-side speed sensor that measures the rotating speed of the moving-side rotating body, and the inlet temperature of the fluid that cools the contact part Contact for determining the temperature of the contact portion based on the temperature sensor for measurement, the command current of the control valve for controlling the hydraulic pressure for pressurizing the contact portion, and the detection signals of the drive speed sensor, the moving speed sensor and the temperature sensor It is configured to have a part temperature calculation part and a comparison part that compares the temperature of the contact part obtained by the contact part temperature calculation part with a predetermined allowable temperature and outputs an operation signal to an alarm device.

[0017]

According to the method of preventing damage of the wet friction transmission device of the present invention configured as described above, the rotational speeds of the driving side rotating body and the sliding side rotating body, the inflow temperature of the fluid for cooling the contact portion, and the contact portion Since the temperature of the contact part and the temperature difference between the inner circumference side and the outer circumference side of the contact part are obtained from the torque, it is possible to accurately know the temperature difference between the contact part and the contact part. It is possible to surely prevent damage due to heat generation in the.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for preventing damage to a wet friction transmission device and a preferred embodiment of the device according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is an explanatory diagram of a damage prevention device for a wet friction transmission device according to a first embodiment of the present invention.

In FIG. 1, a clutch 10 is, for example, a wet-type multi-disc clutch of a retarder, and includes a plurality of disks 14 provided on an input shaft 12 on the drive side and a plurality of disks 14 provided on an output shaft 16 on the side of a drive. The plate 18 and the plate 18 are stored in a case 20. The disc 14 and the plate 18, which are the clutch plates, are formed of a donut-shaped disc, and the surfaces contact each other to transmit the power of the input shaft 12 to the output shaft 16. An input shaft rotation sensor 15 is provided near the input shaft 12, and an output shaft rotation sensor 17 and a torque sensor 19 are provided near the output shaft 16.
The rotational speed of, the rotational speed of the output shaft 16, and the clutch torque can be detected.

The contact pressure between the disc 14 which is the clutch plate and the plate 18 is controlled by a command current i from a clutch pressure command device 42 which will be described later. That is, when the command current i is output from the clutch pressure command device 42 to the control valve 30, the hydraulic pressure (clutch hydraulic pressure P _C ′) corresponding to the command current i is transmitted via the conduit 31 to the clutch piston (not shown).
The contact pressure between the disk 14 and the plate 18 (clutch pressure P _C ) is determined. If the clutch pressure P _C is the area A _{P of the} clutch piston,

## EQU1 ## P _C = P _C '× A _P On the other hand, the case 20 is formed with an inlet through which engine oil, which is a cooling fluid, flows into the case 20, and an outlet through which engine oil that has cooled the disk 14 and the plate 18 flows out from the case 20. (Neither is shown). An oil cooler 26 is connected to the inlet through a pipe 24 so that the engine oil discharged from the oil pump 27 is transferred to the oil cooler 2.
After being cooled by 6, it flows into the case 20. The outlet provided in the case 20 is
The case 2 is communicated with the oil tank 29 through the pipe 28.
The engine oil in 0 can be returned to the oil tank 29. An oil temperature sensor 34 is provided near the inflow port of the case 20 of the pipe line 24 so that the temperature of the engine oil flowing into the clutch 10 (inflow temperature T _i ) can be detected.

The respective detection signals of the input shaft rotation sensor 15, the output shaft rotation sensor 17, the torque sensor 19, and the oil temperature sensor 34 are input to the arithmetic processing unit 40. The arithmetic processing unit 40 transmits a command signal to the control valve 30 to control a contact pressure (clutch pressure P _C ) between the clutch disk 14 and the plate 18 and a clutch pressure command device 42.
And a contact portion temperature calculator 44 to which the detection signals of the input shaft rotation sensor 15, the output shaft rotation sensor 17, the torque sensor 19, and the oil temperature sensor 34 are input, and provided on the output side of the contact portion temperature calculator 44. And an OR circuit 58 to which the output of the comparison unit 50 is input.

The contact portion temperature calculation unit 44 includes an input shaft rotation speed ω ₁ detected by the input shaft rotation sensor 15, an output shaft rotation speed ω ₂ detected by the output shaft rotation sensor 17, and a torque sensor 1.
9. The plate temperature calculator 46 for obtaining the temperature T _{P of the} plate 18 based on the clutch torque T _C detected by 9 and the oil temperature T _i detected by the oil temperature sensor 34, and the oil temperature T _i detected by the oil temperature sensor 34. And a temperature difference calculator 48 for calculating the temperature difference ΔT between the temperature T _{P of the} plate 18 and the plate temperature calculator 46.

The comparison unit 50 includes a first comparison unit 52 to which the output signal of the plate temperature calculator 46 is input and a second comparator 54 to which the output signal of the inner and outer circumference temperature difference calculator 48 is input, and these Comparators 52 and 54 of the reference memory 5 for storing reference signals (T _PO and ΔT _PO ) for comparison.
Have six. This reference value memory 56 is used for the plate 1
8 stores an allowable limit temperature T _PO (for example, 315 ° C.) and an allowable limit inner / outer peripheral temperature difference ΔT _PO (for example, 120 ° C.) of the plate 18. It consists of an allowable limit inner and outer temperature difference storage unit. The output signal of the OR circuit 58, which is the output of the arithmetic processing unit 40, is input to the alarm device 60 and the speaker 6
2 and the indicator lamp 64 are activated.

In the first embodiment configured as described above, the oil temperature sensor 34 is cooled by the oil cooler 26, detects the inflow temperature T _i of the engine oil flowing into the clutch 10, and detects the plate temperature of the arithmetic processing unit 40. Input to the calculator 46 and the inner / outer circumference temperature difference calculator 48. The input shaft rotation speed ω ₁ detected by the input shaft rotation sensor 15, the output shaft rotation speed ω ₂ detected by the output shaft rotation sensor 17, and the clutch torque T _C detected by the torque sensor 19 are calculated by the plate temperature calculation of the calculation processing device 40. Input to the container 46.

The plate temperature calculator 46 is used for the oil temperature sensor 3
4, when the detection signals detected by the input shaft rotation sensor 15, the output shaft rotation sensor 17, and the torque sensor 19 are input,

## EQU00002 ## The temperature of the plate 18 is obtained based on T _{Pi + 1} = T _Pi + Δt1 / CγV (q ' ₁ -q' ₂ ). In the above equation, T _Pi is the temperature of the plate 18 after i hours, T _{Pi + 1}
Is the plate 18 after time Δt (0, 1 sec) from T _Pi
Temperature, C is the specific heat of the plate 18, gamma is the specific gravity of the plate 18, q _'1 friction heat value of the disc 14 and the plate 18, ^q' ₂ is a cooling heat by the cooling fluid. Also,
The frictional heat generation amount q ′ ₁ between the disk 14 and the plate 18 and the cooling heat amount q ′ ₂ due to the cooling fluid are

[Number 3] are determined on the basis of the _{q '1 = a 2 · g} q' 2 = αm · (T P -T i). In the above equation, a ₂ is a constant, g is the frictional heat generation rate between the disk 14 and the plate 18, αm is the heat transfer coefficient between the plate 18 and the cooling fluid, and T _P is the temperature of the plate 18, and Is the same as the temperature of the engine oil (inflow temperature T _i ). The friction heat generation rate g of the disk 14 and the plate 18 is

## EQU4 ## It is obtained based on g = T _C. | Ω ₁ −ω ₂ | / Ad. In the above equation, T _C is the clutch torque detected by the torque sensor 19 described above, and Ad
Is the total area of the contact portion between the disk 14 and the plate 18, that is, the total area of contact to generate frictional heat.

The plate temperature T _P obtained as described above is input to the first comparator 52 of the comparison section 50 and the inner-outer circumference temperature difference calculator 48.

The inner / outer peripheral temperature difference calculator 48 is a comparison unit 50 for determining the inner / outer peripheral temperature difference ΔT _P of the plate 18 based on the following equation.
2 to the second comparator 54.

ΔT _P = T _P −T _i T _P is the temperature of the plate 18 as described above, and T _i
Is the engine oil temperature (inflow temperature) as described above, and the inner peripheral temperature of the plate 18 is equal to the engine oil temperature (inflow temperature) T _i .

The first comparator 52 is a plate temperature calculator 4
When the plate temperature T _P obtained in 6 is input, the plate allowable limit temperature T _PO of the reference value memory 56 is read and compared with the plate temperature T _P. And

When T _P ≧ T _PO , “H” is output to the OR circuit 58. The second comparator 54 compares the inner-outer circumference temperature difference ΔT _P obtained by the inner-outer circumference temperature difference calculator 48 with the allowable limit inner-outer circumference temperature difference ΔT _PO of the reference value memory 56.

When ΔT _P ≧ ΔT _PO , “H” is output to the OR circuit 58.

The OR circuit 58 receives "H" from either the first comparator 52 or the second comparator 54,
An operating signal is output to the alarm device 60, an alarm sound is generated by a buzzer from the speaker 62, and a red alarm lamp 64 is blinked, for example, to notify the operator that the clutch 10 is in a dangerous state where it is damaged by heat generation. To do.

Incidentally,

When T _P <T _PO , when both the first comparator 52 and the second comparator 54 output “L”, the OR circuit 58 is
L "is output, and the alarm device turns on the green lamp 64 indicating that the clutch 10 is safe or normal.

As described above, in the embodiment, the clutch 10 is calculated from the rotational speeds ω ₁ and ω ₂ of the input shaft 12 and the output shaft 16 of the clutch 10, the clutch torque T _C, and the inflow temperature T _i.
Plate temperature T _P , the temperature difference ΔT between the inner and outer circumferences of the plate 18
_{Since P} is required, damage due to heat generation of the clutch can be reliably prevented.

FIG. 2 is an explanatory view of a damage preventing device for a wet friction transmission device according to a second embodiment of the present invention.

In FIG. 2, the same reference numerals as those shown in FIG. 1 indicate the same devices or parts, and the description thereof will be omitted.
In the first embodiment, the clutch torque T _C is detected by the torque sensor 19, but in the second embodiment, the oil pressure sensor 32 is provided in the clutch oil pressure circuit 31 to detect the oil pressure and input to the plate temperature calculator 46 of the processor 40. To do. And the clutch torque T _C is

[Formula 9] T _C = a ₁ · μ · A _P · P _C In the above equation, a ₁ is a constant, μ is a coefficient of friction between the desk 14 and the plate 18, A _P is an area of a piston that presses the desk 14 and the plate 18, and P _C pressurizes the piston. It is hydraulic. Therefore, a value obtained by multiplying the piston area A _P by the hydraulic pressure P _C is the pressure for bringing the desk 14 and the plate 18 into contact with each other. Friction coefficient μ between desk 14 and plate 18
Is

## EQU10 ## μ = f ₁ (ω ₁ , ω ₂ ) That is, the friction coefficient μ is obtained as a function of the input shaft rotation speed ω ₁ and the output shaft rotation speed ω ₂ .

As described above, the oil pressure P _C detected by the oil pressure sensor 32 corresponds to the plate temperature calculator 46 of the processor 40.
The clutch torque T _C is calculated by inputting to
The plate temperature calculator 46 obtains the plate temperature T ₀ in the same manner as the operation described in the first embodiment shown in FIG.
₀ is input to the first comparator 52 and the inner-outer circumference temperature difference calculator 48 of the comparison unit 50.

The inner / outer temperature difference calculator 48 calculates the inner / outer temperature difference Δ.
T _P is calculated, and the inner-outer peripheral temperature difference ΔT ₀ is input to the second comparator 54 of the comparison unit 50.

The first comparator 52 is a plate temperature calculator 4
When the plate temperature T _P obtained in 6 is input, the plate allowable limit temperature T _PO of the reference value memory 56 is read and compared with the plate temperature T _P. And

If T _P ≧ T _PO , “H” is output to the OR circuit 58. The second comparator 54 compares the inner-outer circumference temperature difference ΔT _P obtained by the inner-outer circumference temperature difference calculator 48 with the allowable limit inner-outer circumference temperature difference ΔT _PO of the reference value memory 56.

If ΔT _P ≧ ΔT _PO , “H” is output to the OR circuit 58.

The OR circuit 58 receives "H" from either the first comparator 52 or the second comparator 54,
The operator is informed that the clutch 10 is in a dangerous state in which the clutch 10 is damaged by heat generation by outputting an operation signal to the alarm device 60, causing the speaker 62 to generate an alarm benefit by the buzzer, and blinking the red alarm lamp 64, for example. To do.

Incidentally,

If T _P <T _PO , then when both the first comparator 52 and the second comparator 54 output “L”, the OR circuit 58 is
L "is output, and the alarm device turns on the green lamp 64 indicating that the clutch 10 is safe or normal.

As described above, in the embodiment, the plate temperature T _{P of} the clutch 10 is calculated from the rotational speeds ω ₁ and ω ₂ of the input shaft 12 and the output shaft 16 of the clutch 10, the clutch hydraulic pressure P _C, and the inflow temperature T _i . Inner and outer temperature difference of plate 18 ΔT _P
Therefore, it is possible to reliably prevent damage due to heat generation of the clutch.

FIG. 3 is an explanatory view of a damage prevention device for a wet friction transmission device according to a third embodiment of the present invention.

In FIG. 3, the same reference numerals as those shown in FIG. 1 indicate the same devices or parts, and the description thereof will be omitted.
In the first embodiment, the torque sensor 19 detects the clutch torque T _C , but in the third embodiment, the clutch pressure command unit 42 that outputs the clutch pressure command to the control valve 30 that controls the clutch hydraulic pressure.
Of the command current is detected to obtain the clutch torque T _C.

The clutch pressure command unit 42 outputs the clutch pressure command current i to the control valve 30 and also outputs it to the plate temperature calculator 46.

When the clutch pressure command current i is output to the plate temperature calculator 46, the plate temperature calculator 46 reads the oil pressure P _C from a memory which stores the relationship between the clutch pressure command current i and the oil pressure P _C. When the hydraulic pressure P _C is read, the clutch torque T _C is obtained by the following equation.

[Equation 14] It is obtained based on T _C = a ₁ · μ · A _P · P _C. In the above equation, a ₁ is a constant, μ is a coefficient of friction between the desk 14 and the plate 18, A _P is an area of a piston that presses the desk 14 and the plate 18, and P _C pressurizes the piston. It is hydraulic. Therefore, a value obtained by multiplying the piston area A _P by the hydraulic pressure P _C is the pressure for bringing the desk 14 and the plate 18 into contact with each other. Friction coefficient μ between desk 14 and plate 18
Is

(15) μ = f ₁ (ω ₁ , ω ₂ ) That is, the friction coefficient μ is obtained as a function of the input shaft rotation speed ω ₁ and the output shaft rotation speed ω ₂ .

[0044] When the clutch torque T _C is obtained, the following operation Like plate temperature calculator 46 described in the first embodiment shown in FIG. 1 obtains the plate temperature T _P, the comparison unit 50 the plate temperature T _P 1 Input to the comparator 52 and the inner / outer circumference temperature difference calculator 48.

The inside / outside temperature difference calculator 48 calculates the inside / outside temperature difference Δ.
T _P is calculated, and the inner / outer peripheral temperature difference ΔT _P is input to the second comparator 54 of the comparison unit 50.

The first comparator 52 is the plate temperature calculator 4
When the plate temperature T _P obtained in 6 is input, the plate allowable limit temperature T _PO of the reference value memory 56 is read and compared with the plate temperature T _P. And

If T _P ≧ T _PO , “H” is output to the OR circuit 58. The second comparator 54 compares the inner-outer circumference temperature difference ΔT _P obtained by the inner-outer circumference temperature difference calculator 48 with the allowable limit inner-outer circumference temperature difference ΔT _PO of the reference value memory 56.

If ΔT _P ≧ ΔT _PO , “H” is output to the OR circuit 58.

The OR circuit 58 receives "H" from either the first comparator 52 or the second comparator 54,
An operating signal is output to the alarm device 60, an alarm sound is generated by a buzzer from the speaker 62, and a red alarm lamp 64 is blinked, for example, to notify the operator that the clutch 10 is in a dangerous state where it is damaged by heat generation. To do.

Incidentally,

If T _P <T _PO , when both the first comparator 52 and the second comparator 54 output “L”, the OR circuit 58 operates
L "is output, and the alarm device turns on the green lamp 64 indicating that the clutch 10 is safe or normal.

As described above, in the embodiment, the clutch ₁ is calculated from the rotational speeds ω ₁ and ω ₂ of the input shaft 12 and the output shaft 16 of the clutch 10, the clutch pressure command current i, and the inflow temperature T _i.
The plate temperature T _{P of} 0 and the inner / outer peripheral temperature difference Δ of the plate 18
Since T _P is sought, damage due to heat generation of the clutch can be reliably prevented.

[0050]

As described above, according to the present invention, the contact portion is calculated from the rotational speeds of the driving side rotating body and the sliding side rotating body, the temperature of the fluid for cooling the contacting portion, and the torque capacity of the contacting portion. Since the heat generation state of the contact portion is determined by obtaining the temperature of No. 3, it is possible to prevent damage to the wet friction transmission device due to frictional heat and to add a torque sensor to the conventional device.

Moreover, since the temperature difference between the two different points in the radial direction of the rotating body is taken into consideration, the difference in thermal expansion due to the temperature difference between the inner peripheral side and the outer peripheral side of the plate-like rotating body is also taken into consideration. The damage due to the dish-shaped deformation of the rotary body can be prevented.

Further, since the torque capacity is obtained by measuring the torque capacity of the contact portion and the hydraulic pressure that determines the contact pressure of the contact portion, it is only necessary to add a hydraulic pressure sensor to the conventional device.

Further, since the torque capacity of the contact portion is obtained by the command current of the control valve for controlling the hydraulic pressure that determines the contact pressure of the contact portion, it is not necessary to add a sensor to the conventional device. Yes.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a damage prevention device for a wet friction transmission device according to a first embodiment.

FIG. 2 is an explanatory view of a damage prevention device for a wet friction transmission device according to a second embodiment.

FIG. 3 is an explanatory diagram of a damage prevention device for a wet friction transmission device according to a third embodiment.

FIG. 4 is a diagram showing a clutch damage mode based on a temperature of a clutch plate or a temperature difference between an inner peripheral side temperature and an outer peripheral side temperature of the wet multi-plate clutch.

FIG. 5 is a diagram showing how to obtain a vehicle speed when descending a slope described in a conventional retarder instruction manual.

[Explanation of reference numerals] 10 clutch 12 input shaft 14 disk 15 input shaft rotation sensor 16 output shaft 17 output shaft rotation sensor 18 plate 19 torque sensor 30 control valve 31 hydraulic circuit 32 hydraulic sensor 34 oil temperature sensor 40 arithmetic processing unit 42 clutch pressure Commander 44 Calculation processing unit 46 Plate temperature calculation unit 48 Inner and outer circumference temperature difference calculation unit 50 Comparison unit 52, 54 Comparator 56 Reference memory 58 OR circuit 60 Alarm device 62 Speaker 64 Display lamp

Claims (8)

[Claims] 1. A method for preventing damage to a wet friction transmission that changes a contact pressure at a contact portion between a drive-side rotating body and a moving-side rotating body to change a power transmission rate, and a rotational speed of the drive-side rotating body. , The temperature of the contact portion is obtained from the rotation speed of the moving side rotating body, the inlet temperature of the fluid for cooling the contact portion, and the torque capacity of the contact portion, and a caution signal is output when this temperature is equal to or higher than the reference value. A method for preventing damage to a wet friction transmission device, the method comprising: 2. The method for preventing damage to a wet friction transmission according to claim 1, wherein the temperature of the contact portion is a temperature difference between two points of the contact portion in different radial directions. 3. The method for preventing damage to a wet friction transmission according to claim 1, wherein the torque capacity of the contact portion is obtained from the contact pressure. 4. The method for preventing damage to a wet friction transmission according to claim 1, wherein the torque capacity of the contact portion is obtained from a command current of a control valve that controls contact pressure. 5. A damage prevention device for a wet friction transmission that changes a contact pressure at a contact portion between a drive side rotating body and a moving side rotating body to change a power transmission rate, and a rotational speed of the drive side rotating body is changed. A drive speed sensor for measurement, a driven speed sensor for measuring the rotation speed of the moving side rotating body, a temperature sensor for measuring the inlet temperature of the fluid for cooling the contact portion, and a torque sensor for measuring the torque of the output shaft. A contact portion temperature calculation unit that obtains a temperature of a contact portion based on detection signals of the drive speed sensor, the traveling speed sensor, the temperature sensor, and the torque sensor, and the contact portion temperature calculation unit that calculates the contact temperature. A damage prevention device for a wet friction transmission, comprising: a comparison unit that compares a temperature of a contact portion with a predetermined allowable temperature and outputs an operation signal to an alarm device. 6. A damage preventive device for a wet friction transmission that changes a contact pressure at a contact portion between a drive-side rotating body and a moving-side rotating body to change a power transmission rate. A drive speed sensor that measures, a driven speed sensor that measures the rotation speed of the moving side rotating body, a temperature sensor that measures the inlet temperature of the fluid that cools the contact part, and a hydraulic pressure that measures the hydraulic pressure that pressurizes the contact part. A sensor, a contact side temperature calculating section for obtaining a temperature of a contact section based on detection signals of the driving side speed sensor, the moving side speed sensor, the temperature sensor and the hydraulic pressure sensor, and the contact section temperature calculating section. And a comparison unit that compares the temperature of the contact portion obtained in step 1 with a predetermined allowable temperature and outputs an operation signal to an alarm device. 7. A torque sensor for measuring torque of an output shaft, a hydraulic sensor for measuring hydraulic pressure for controlling contact pressure instead of a detection signal for the torque sensor, and a detection signal for the hydraulic sensor. The damage prevention device for a wet friction transmission device according to claim 5 or 6. 8. The torque sensor for measuring the torque of the output shaft and the command current of the control valve for controlling the contact pressure instead of the detection signal of the torque sensor, according to claim 5 or 6. Damage prevention device for wet friction transmission.