JPH0122495B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an overheat prevention device for a clutch that can prevent a clutch that can connect and disconnect power from generating heat due to slippage and ultimately being damaged.

[Conventional technology]

Conventionally, clutches, whether mechanical or electrical, have been subject to slippage during power transmission, and this slippage can generate heat, overheating the clutch and causing damage depending on the usage conditions. There was also a risk of This clutch overheating will be explained, for example, in the case of an electromagnetic clutch. The electromagnetic clutch for vehicles automates the clutch control when starting the vehicle and changing gears, and the clutch torque is controlled by detecting the engine speed, allowing smooth starting. It is. Therefore, there is no sudden clutch engagement at the time of starting, and engine stalling due to failure in clutch operation does not occur.

[Problem to be solved by the invention]

However, when starting a vehicle on a steep slope near the limit of its climbing ability, the clutch slips at a rotational speed that balances running resistance and engine torque, and has the characteristic of not stalling the engine while transmitting engine torque. (In manual cars, the engine stalls). However, if this state is maintained, the clutch will continue to generate heat due to continuous slipping, and in the worst case, there is a problem that the clutch function may be impaired. In addition, as a prior art related to this, Utility Model Opening 55-
There is a publication number 35000.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention provides means for detecting the rotational speed provided on each of the driving side and the driven side of the clutch, and a rotational speed difference between the pair of rotational speed detection means based on a predetermined standard. It comprises a comparison means for comparing the value, a timer means operated by a signal from the comparison means, and a connection characteristic changing means. activating the timer means;
The timer means is arranged to directly engage the clutch after a set time has elapsed.

【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 a cylindrical end portion of the cap 13 is loosely fitted onto the input shaft 9, and a slip ring 14 is inserted therein.
is attached, and a lead wire X is connected between this slip ring 14 and the drive member 8,
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 unites the drive member 8 and the driven member 10, and the engine power from 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 arranged 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, thereby causing the pick-up 39 to connect to the input shaft 9, The rotation speed of the driven 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
The signal is input to a (digital/analog) converter 41, and the output of the D/A converter 41 is input to one end of an inverter 42. 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 comparator 44. The output of the pickup 39 is input to a D/A converter 45.
5 is input to the other end of the adder 43 via a resistor 46, and the output of the reference voltage generator 47 is input to the other end of the comparator 44. This comparator 44 outputs a high level signal when the output of the adder 43 is larger than the reference value from the reference voltage generator 47. This output is input to the timer 48, and the output of the timer 48 is It is connected to the coil of a relay 49 for changing connection characteristics. Next, FIG. 4 shows the configuration of the control circuit of the electromagnetic powder clutch 1. A PNP type transistor 50 and an NPN type transistor 51 are connected in series to both ends of the coil 7, respectively.
The emitter of transistor 5 is connected to the power supply and
The 1st emitter is grounded. And coil 7
A commutation circuit 52 consisting of a diode and a resistor is connected between both ends of the transistor 51.
A resistor 53 for reverse excitation is connected between the collector of the transistor 50 and a resistor 54 for reverse excitation is also connected between the collector of the transistor 50 and ground. A resistor 55 is connected to the base of each transistor 50, 51.
56 is connected to the resistor 55, the output end of the buffer 57 is connected to the resistor 55, and the output of the NOR gate 58 is connected to the resistor 56. The input terminal of the buffer 57 and one input terminal of the NOR gate 58 are connected to each other, and the other input terminal 5 of the NOR gate 58 is connected to each other.
9 is input with a clutch control signal. 60 is an accelerator switch that is turned on when the accelerator pedal is depressed, 61 is a vehicle speed switch that is turned on when the vehicle speed is higher than a set vehicle speed _V1 , and 62 is a shift lever switch that is provided on the shift lever and is turned on when the gear is changed. Accelerator switch 60 and vehicle speed switch 6
1 is connected to a NAND gate 63, the output of the NAND gate 63 and the shift lever switch 62 are connected to a NAND gate 64, and the output of the NAND gate 64 is connected to the buffer 57 and NOR gate 58. One end of each switch 60, 61, 62 is grounded, and a resistor 6 is connected to the other end.
A positive voltage is applied via terminals 5, 66, and 67.
A direct-coupled switch 68 is connected in parallel with the vehicle speed switch 61.
is opened and closed by the relay 49, and when the signal from the timer 48 is at a low level, the direct connection switch 68 is off. 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 rotational speed between the crankshaft 5 and the input shaft 9 and the electromagnetic powder clutch 1 is slipping, the amount of heat generated is the difference between the crankshaft 5 (driving side) and the input shaft 9 (driven side). It is related to the difference between the rotation speeds ωi and ω ₀ (ωi − ω ₀ ) and the clutch torque Tc, and by integrating the product of this rotation speed difference and the clutch torque over the slip time, the accurate total heat generation amount Q can be calculated. It is something. However, as mentioned above,
When the engine torque and running resistance are balanced and the slip continues, the amount of heat generated by the clutch is proportional to the product of the rotational speed difference (ωi - ω ₀ ) and the slip time t, so the rotational speed If the difference (ωi - ω ₀ ) exceeds a predetermined value and the rotation speed difference (ωi - ω ₀ ) continues for more than a predetermined time, it is approximately determined that overheating has occurred. It is not a mistake to do so. This determination can be made by the detection circuit shown in FIG. Regarding FIG. 3, since the ignition pulse 40 outputs a number of pulse waves proportional to the rotational speed of the engine, that is, the crankshaft 5, this ignition pulse 40 is outputted by the D/A converter 41 to the engine. DC voltage signal ωi proportional to rotation speed
Convert to In addition, the pick-up 39 is connected to the input shaft 9.
Since it outputs a number of pulse waves proportional to the rotation speed of the input shaft 9, the D/A converter 45 converts it into a DC voltage proportional to the rotation speed of the input shaft 9, and passes it through the resistor 46 to obtain the signal ω _0. . These two signals ωi and ω ₀ are
This is corrected by a resistor 46 so that when the rotational speeds of the crankshaft 5 and the input shaft 9 are the same, the voltage values are the same. The sign of the signal ωi is inverted to −ωi by the inverter 42, and the signal −ωi and ω ₀ are added by the adder 43, and the output signal of the adder 43 becomes (ωi−ω ₀ ).
The output of this adder 43 is input to a comparator 44 and compared with a reference value α from a reference voltage generator 47.
The reference value α generated by the reference voltage generator 47 is used to define a range within which the rotational speed difference ( _ωi − ω ₀ ) is allowable below a certain level. If it is smaller than the reference value α, the output of the comparator 44 is at low level, and conversely, if the difference in rotational speed (ωi − ω ₀ ) is larger than the reference value α, the output of the comparator 44 is low level.
The output of No. 4 becomes high level. When the output of the comparator 44 becomes high level, the timer 48 starts timing operation from that point on, and when the high level signal continues from the comparator 44 for a predetermined time _t1 , the timer 48 starts relaying. The connection characteristic of the electromagnetic powder clutch 1 is changed by outputting a signal β to the terminal 49. When the signal β flows through this relay 49, the direct coupling switch 68 turns on, changing the slip control to direct coupling control, increasing the load on the engine and causing the engine to stall, thereby reducing the heat generated by the clutch slipping. prevent damage from occurring. Next, control of the clutch current flowing through the coil 7 will be explained with reference to FIG. When the vehicle speed is equal to or higher than the set vehicle speed _V1 , the accelerator pedal is depressed, and the shift lever is not operated, the accelerator switch 60 and vehicle speed switch 61 are on, and the shift lever switch 62 is off, so the Nand gate 64 is in the low state. A level signal is output, the clutch current flows in the order of a→b→c→d, and the electromagnetic powder type clutch 1 is controlled by the clutch control current applied to the input terminal 59. When the accelerator switch 60 and the vehicle speed switch 61 are turned off or the shift lever switch 62 is turned on, the NAND gate 64 outputs a high level signal, and current flows in the order of a→c→b→e to perform reverse excitation. Although the clutch current is controlled in this way, the electromagnetic powder clutch 1 overheats and the comparator 4
When the signal from 8 is transmitted to the relay 49, the direct connection switch 68 is turned on, and a low level signal is always applied to the NAND gate 63 regardless of whether the vehicle speed switch 61 is on or off. Output. Therefore, the clutch current flows in the order of a → b → c → d to directly connect the electromagnetic powder clutch 1, and if the electromagnetic powder clutch 1 overheats due to starting on a steep slope, it will put a high load on the engine and stall it. It is possible to prevent torque from being transmitted to the electromagnetic powder clutch 1 any further.

【Effect of the invention】

Since the present invention is constructed as described above, the amount of heat generated by the clutch can be directly detected, and when the clutch becomes overheated, the clutch is directly connected to prevent further heat generation, thereby preventing damage to the clutch. .

[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, FIG. 4, is a specific electrical circuit diagram for controlling the clutch current. 1... Electromagnetic powder clutch, 39... Pickup, 40... Ignition pulse, 43... Adder, 44... Comparator, 47... Reference voltage generator, 48... Timer, 49... Relay ,69...
...Directly connected switch.

Claims (1)

[Claims] 1 means for detecting the rotational speed provided on each of the driving side and driven side of the clutch; a comparison means for comparing the difference in rotational speed between the pair of rotational speed detection means with a predetermined reference value; It is equipped with a timer means operated by a signal and a connection characteristic changing means, and the difference between the rotations of the driving side and the driven side of the clutch is
A clutch overheat prevention device characterized in that a timer means is operated when the temperature is greater than a reference value to be compared, and the clutch is directly connected after the timer means has elapsed for a set time.