JPS642818B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for detecting overheating of a clutch which can prevent a clutch capable of connecting and disconnecting power from generating heat and being damaged due to slippage.

[Conventional technology and issues]

Conventionally, clutches did not rely on mechanical or electrical configurations, and slippage occurred during power transmission, and this slippage turned into heat, overheating the clutch, and depending on the usage conditions, there was a risk of damage. .
This clutch overheating will be explained with reference to an electromagnetic clutch.

An electromagnetic clutch for a vehicle automates the clutch control when starting the vehicle and shifting gears, and the clutch torque is controlled by detecting the engine speed, allowing smooth starting. . Therefore, there is no sudden clutch engagement at the time of starting, and engine stalling due to failure in clutch operation does not occur. However, when starting a vehicle on a steep slope that is close to the limit of its climbing ability, the clutch slips at a rotational speed that balances running resistance and engine torque, and the clutch does not stall while transmitting engine torque (manual vehicle). (This will cause the engine to stall). If this state continued, the clutch would continue to generate heat due to continuous slipping, and in the worst case, there was a risk that the clutch function would be impaired. For this reason, in the past, the clutch temperature was detected during clutch operation to prevent damage to the clutch (for example, Japanese Patent Application No. 136560/1983 filed by the same applicant). However, since electromagnetic clutches have a sealed structure, it is difficult to directly measure the temperature of the clutch's heat-generating part, so it is necessary to detect the temperature outside the clutch or near the housing. Detection of sudden temperature rises was delayed, and the damage prevention function could not be fully achieved in some cases.

In addition, there is Utility Model Application Publication No. 55-35000 as a prior art.

In view of the above-mentioned drawbacks, the present invention provides a method for detecting overheating of a clutch, which can directly and quickly detect the amount of heat generated by the clutch.

[Means to solve the problem]

In order to achieve the above object, the present invention provides means for detecting the rotational speed provided on each of the driving side and the driven side of the clutch, a calculating means for calculating signals from the pair of rotational speed detecting means, and a calculating means for calculating the signals from the pair of rotational speed detecting means. and a comparison means for comparing the signal from the means with a predetermined reference value, the difference between the rotational speeds of the driving side and the driven side of the clutch is multiplied by the rotational speed of the driving side, and then integrated, and the integrated calculation result is The comparator is configured to output a signal indicating overheating when the temperature exceeds a predetermined reference value.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In this embodiment, the present invention will be explained by embodying an electromagnetic powder clutch, which is a type of electromagnetic clutch.

In Figures 1 and 2, the electromagnetic powder clutch assembled into the transaxle type transmission will be explained in detail. Reference numeral 1 is the electromagnetic powder clutch, 2 is the 4-speed forward transmission, and 3 is the electromagnetic powder clutch. is the final gearbox.

In the electromagnetic powder clutch 1, a drive member 8 containing a built-in coil 7 is integrally connected to a crankshaft 5 from the engine via a drive plate 6 within a clutch case 4 having a sealed structure. 10 are spline-fitted so as to be integrated in the rotational direction, and are closely fitted to the drive member 8 via a gap 11, and electromagnetic powder from the powder chamber 12 is accumulated in this gap 11. Further, a cap 13 is integrally connected to the drive member 8, and its cylindrical end is loosely fitted onto the input shaft 9, and a slip ring 14 is attached thereto. Lead wire X is connected to
As shown in detail in FIG.
7 and is in sliding contact to supply power to the coil 7.

With this configuration, the drive plate 6 and the drive member 8 rotate together with the crankshaft 5, and the electromagnetic powder sealed in the powder chamber 12 is appropriately gathered toward the inner peripheral surface of the drive member 8 by centrifugal force. There is. Therefore, from the lead wire Y to the brush 16,
When power is supplied to the coil 7 via the slip ring 14 and the lead wire The powder gathers closely together and forms a gap of 1.
1, the drive member 8 and the driven member 10 are integrated, and the engine power of the crankshaft 5 is transmitted to the input shaft 9.

Next, in the transmission 2, first to fourth speed drive gears 18 to 21 are integrally provided to an input shaft 9 from the clutch 1, and an output shaft 22 is disposed parallel to the input shaft 9. There is a driven gear 23 that constantly meshes with each of the above gears 18 to 21.
26 are rotatably fitted, and adjacent 2
Driven gears 23 and 24 are connected to the output shaft 22 by a synchronization mechanism 27, driven gears 25 and 26 are connected to the output shaft 22 by another synchronization mechanism 28, and these input and output shafts 9, A gear mechanism 29 for reversing is provided between 22 and 22 . In this way, by operating a change lever (not shown), the synchronizer 27 moves the driven gear 23 to the output shaft 2.
2, the power of the input shaft 9 is most decelerated by the gears 18 and 23 and taken out to the output shaft 22 to obtain the first speed, and thereafter each speed change is performed in the same manner. In the case of the transmission 2, there is a gear 21.
A pick-up 39 is provided which approaches the input shaft 9 and converts the change in magnetic flux into an electric signal.As the gear 21 rotates, the tooth surface formed on the outer periphery cuts the magnetic path. The rotation speed of the member 10 can be detected.

Further, an output gear 30 is provided at the end of the output shaft 22.
is provided and meshes with the ring gear 32 in the differential device 31 of the final reduction gear 3, so that the power of the output shaft 22 of the transmission 2 is immediately transferred from the ring gear 32 to the side gear via the case 33, spider 34, and pinion 35. 36 and further transmitted to the drive wheels via the axle 37.

Figure 3 shows the configuration of the calorific value detection circuit.
Engine ignition pulse 40 is D/A
It is input to a (digital/analog) transmission 41, and the output of the D/A transmission 41 is input to an inverter 42 and one end of a multiplier 44. The output of the inverter 42 is input to one end of an adder 43, and the output of the adder 43 is input to the other end of a multiplier 44. The output of the pickup 39 is input to a D/A converter 45,
The output of the D/A converter 45 is input to the other end of the adder 43 via a resistor 46. The output of the multiplier 44 is input to an integrator 47, the output of this integrator 47 is input to one end of a comparator 48, and the output of the reference voltage generator 50 is input to the other end of the comparator 48. are doing. An alarm 49 such as a buzzer or a lamp is connected to the output of the comparator 48. Further, 51 is an accelerator switch that is provided on the accelerator pedal and is turned on when the accelerator pedal is depressed.
It is connected to the start signal end of 7.

Next, the operation of this embodiment will be explained.

In the electromagnetic powder clutch 1 described above, the crankshaft 5 and the input shaft 9 are connected by the current flowing through the coil 7, and the output torque of the engine can be transmitted in the direction of the transmission 2. Here, when there is a difference in the rotational speed of the crankshaft 5 and the input shaft 9 and the electromagnetic powder clutch 1 is slipping, the amount of heat generated Q is: Q=∫ ^t1 _p (ωi=ωo)・Tc dt …( 1). Here, Q is the amount of heat generated, _t1 is the slip time, ωi is the rotational angular velocity of the crankshaft 5, ωo is the rotational angular velocity of the input shaft 9, and Tc is the clutch torque. The characteristics of the clutch torque when the electromagnetic powder clutch 1 starts is expressed as Tc=f(ωi) (2), so the above equation (1) becomes as follows.

Q=∫ ^t1 _p (ωi−ωo)・f(ωi)dt …(3) Approximately, if Tc=α・ωi, equation (3) becomes Q=α・∫ ^t1 _p ωi(ωi− ωo)dt…(4) Q′=Q/α=∫ ^t1 _p ωi(ωi−ωo)dt…(5) From this, if we detect the rotational speed of the drive member 8, that is, the crankshaft 5, and the rotational speed of the driven member 10, that is, the input shaft 9 of the electromagnetic powder clutch 1, and calculate the equation (5) electrically, The amount of heat generated by the electromagnetic powder clutch 1 can be detected.

The above calculation can be performed by the control circuit shown in FIG. 40 is converted by a D/A converter 41 into a DC voltage signal ωi proportional to the rotational speed of the engine. Also, since the pickup 39 outputs a number of pulse waves proportional to the rotational speed of the input shaft 9, the D/A converter 45 converts the pulse waves into a DC voltage proportional to the rotational speed of the input shaft 9, which passes through the resistor 46. By doing so, we obtain the signal ωo. These two signals ωi and ωo have the same voltage value if the rotational speeds of the crankshaft 5 and the input shaft 9 are the same. The sign of the signal ωi is inverted to -ωi by an inverter 42, and the signals -ωi and ωo are added together by an adder 43, so that the output signal of the adder 43 becomes (ωi - ωo). Since the multiplier 44 receives the signal (ωi-ωo) added to the detection signal ωi, its output signal becomes ωi (ωi-ωo), and this multiplied signal is sent to the integrator 47.
Enter. The integrator 47 does not operate at all when the accelerator pedal is not depressed and the electromagnetic powder clutch 1 is not connected, but when the accelerator pedal is depressed and the accelerator switch 51 is turned on,
Integral operation is performed from the time it is turned on. For this reason,
The voltage value of the calculation signal of the integrator 47 is Q=∫ ^t1 _p (ωi−ωo)dt=Q′. This calculation signal Q' has a voltage value proportional to the amount of heat generated. This calculation signal Q' is input to the comparator 48, and since the reference voltage β from the reference voltage generator 50 is input to the comparator 48, the amount of heat generated by the electromagnetic powder clutch 1 is small. In the case of β, no signal is output and the alarm 49 does not operate. However, when the calorific value Q' increases and Q'≧β, the comparator 48 outputs a signal to the alarm 49 and activates a buzzer or lamp to notify that the temperature of the electromagnetic powder clutch 1 has suddenly increased. This prevents burnout from occurring.

FIG. 4 shows another embodiment of the present invention, and the same components are denoted by the same reference numerals and the explanation thereof is omitted.

The calculation output of the integrator 47 is sent to comparators 48 and 52.
The output of the reference voltage generator 50 is input to the comparator 48 via a resistor 53 and directly to the comparator 52. An alarm 49 is connected to the comparator 48, and a connection characteristic changing circuit 54 is connected to the comparator 52.

In this embodiment, the calculation signal Q' of the integrator 47 is δ
When the voltage exceeds the voltage, the comparator 48 first outputs a signal to activate the alarm 49, and the electromagnetic powder clutch 1 is activated.
Alerts you that the is overheating. This alarm 49
The accelerator switch 51 is still activated due to the notification by
is turned on to connect the electromagnetic powder clutch 1, the calculated signal Q' becomes higher, and when Q'>γ, the comparator 52 outputs a signal to change the characteristics of the connection characteristic changing circuit 54. , the control current flowing through the coil 7 is increased to directly connect the electromagnetic powder clutch 1. Because of this, the engine stops its rotation and
This will forcibly prevent the electromagnetic powder clutch 1 from generating heat.

〔Effect of the invention〕

Since the present invention is constructed as described above, the amount of heat generated by the clutch can be detected reliably and quickly, and damage to the clutch due to overheating can be prevented.

[Brief explanation of drawings]

Fig. 1 is a side sectional view of an electromagnetic powder clutch embodying the present invention, Fig. 2 is a sectional view taken along the Z--Z line in Fig. 1, and Fig. 3 shows the control system of this embodiment. The block diagram in FIG. 4 is another embodiment of the invention. 1...Electromagnetic powder clutch, 39...Pickup,
40...Ignition pulse, 43...Adder, 4
4... Multiplier, 47... Integrator, 48... Comparator.

Claims (1)

[Claims] 1. Means for detecting the rotation speed provided on each of the driving side and driven side of the clutch, a calculation means for calculating the signals from the pair of rotation speed detection means, and a calculation means for calculating the signals from the calculation means with a predetermined reference value. and integrating the difference between the rotational speeds of the driving side and the driven side of the clutch by the rotational speed of the driving side, and when the integrated calculation result becomes larger than a predetermined reference value. A method for detecting overheating of a clutch, characterized in that a comparison means outputs a signal indicating overheating.