JPH02107829A - Automatic clutch control device for vehicle - Google Patents

Abstract

PURPOSE:To prevent the burning most efficiently by controlling a clutch to be switched to the direct mode and while judging the direct mode with the low direct speed, and detecting the clutch temperature directly in the case that the clutch temperature detected by a clutch temperature detecting means exceeds the predetermined temperature. CONSTITUTION:In the case that the wheels stack at the time of starting on a snow-covered road, though the clutch heating value is increased, this temperature is directly detected by a clutch temperature detecting means 40 provided in a circuit of coil 2c, and a turn-on mode judging unit 34 is forcedly switched to the direct mode side by a clutch overheating judging unit 45 at the time of Tc>=TL in the relation of the clutch coil temperature Tc and the coil limitation temperature TL. Thereby, an electro-magnetic powder type clutch 2 is immediately held to be engaged by the direct current, and the engine speed lowers and while coincides with the primary pulley rotating speed, and thereafter, the heat generation with the slip is eliminated. The burning is thus prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an automatic clutch control device installed in a vehicle drive system that electronically controls clutch torque, and more particularly, to a control device for an automatic clutch that is installed in a vehicle drive system and that electronically controls clutch torque. It is something.

[Conventional technology]

Many automatic clutches for vehicles of this type, such as electromagnetic clutches, have already been proposed by the applicant. Most of these involve operating the accelerator pedal and shift lever in transient states such as when starting, and in steady states after direct clutch engagement.

The clutch torque is optimally controlled in relation to driving conditions, engine status, etc., and furthermore, in combination with a manual transmission or a belt-type continuously variable transmission, appropriate control is performed.

Particularly in recent years, electronic control of not only engines but also drive system clutches, transmissions, etc. has progressed, and there is a trend toward even more fine-grained control of automatic clutches.

Conventionally, regarding the start control of the automatic clutch for a vehicle, there is a prior art, for example, disclosed in Japanese Patent Application Laid-Open No. 131430/1983, in which the clutch torque is gradually increased to smoothly engage the clutch at the time of start. And the clutch person,
It is shown that the direct coupling vehicle speed is set near where the output side rotation speed matches, and when this direct coupling vehicle speed is reached, the clutch is engaged to maintain the direct coupling state, reducing the shock when the clutch is engaged, and when the accelerator is released. This system is designed to ensure engine braking when exiting the plane.

In such start control, a difference occurs between the rotational speed of the clutch and the output side, causing slippage, which inevitably generates heat.

Here, when the load on the wheel side is not very large, such as when driving on a dry road surface, the clutch output side rotational speed and vehicle speed quickly increase with predetermined characteristics, so the amount of heat generated is small. However, when starting under a high load on a snowy road or sandy road, the wheels become stuck in sand, etc., and a large load is applied, which delays the rise in vehicle speed, increases slippage and heat generation, and may damage the clutch. be. For this reason, it is desirable to add measures to prevent clutch burnout to the above-mentioned start control.

Conventionally, there is a prior art technique for preventing burnout of the clutch at the time of starting, for example, as disclosed in Japanese Patent Application Laid-Open No. 61-252924. Here, it is shown that the running load is detected from the time it takes to reach a predetermined vehicle speed at the time of starting, and the clutch characteristics are changed to one with less slip in response to the running load.

[Problem to be solved by the invention]

By the way, the above-mentioned prior art method indirectly estimates the clutch temperature by determining the running load from the rising state of the vehicle speed, so it lacks an accurate grasp of the clutch temperature and cannot directly and effectively prevent clutch burnout. difficult to do. Furthermore, the clutch characteristics must be changed in a very short period of time, making control difficult.

The present invention has been made in view of the above, and an object of the present invention is to provide a control device for a vehicle automatic clutch that is capable of directly detecting clutch temperature and most effectively preventing burnout. It is about providing.

[Means to solve the problem]

In order to achieve the above object, the control device of the present invention sets at least a predetermined direct-coupling vehicle speed, and after the above-mentioned direct-coupling vehicle speed is reached, the clutch is maintained in an engaged state in a direct-coupling mode. It has a clutch temperature detection means that directly detects the temperature, sets a direct coupling vehicle speed lower than normal in the control system in the direct coupling mode, and when the temperature of the clutch according to the clutch temperature detection means exceeds the set temperature, The clutch is controlled to be switched to the direct coupling mode, and the direct coupling mode is determined at a low coupling vehicle speed.

[For production]

Based on the above configuration, the temperature associated with clutch slip when starting on a snowy road or the like is directly detected by the clutch temperature detection means, and the state of heat generation can be immediately grasped. and,
If the temperature of the clutch exceeds the set temperature and there is a risk of burnout, the clutch is switched to the direct coupling mode in which it is fully engaged, and the mode is switched to the direct coupling mode at a low vehicle speed to prevent further slipping and heat generation. Completely blocked, actively preventing clutch burnout.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

Referring to FIG. 1, the overall configuration of a drive system that combines an electromagnetic clutch and a belt-type continuously variable transmission will be described. The engine 1 is connected to a continuously variable transmission 4 via an electromagnetic powder clutch 21 and a forward/reverse switching device 3. Output shaft 6. Differential gear 7
The power is transmitted to the drive wheels 9 via the axle 8 .

The electromagnetic powder clutch 2 has a drive member 2a on the engine crankshaft 10, and a driven member 2b on the input shaft 11 with a clutch coil 2c. Then, due to the clutch current flowing through the clutch coil 2C, both members 2a,
Electromagnetic particles are combined and accumulated in a chain in the gap between the parts 2b, and the resulting binding force variably controls clutch engagement and clutch torque.

The forward/reverse switching device 3 is configured in a synchronous anastomosis type between an input shaft 11 and a transmission main shaft 12 by gears, a hub, or a sleeve, and has at least a forward position where the input shaft 11 is directly connected to the main shaft 12, and a forward position where the input shaft 11 is directly connected to the main shaft 12. 11 is reversed and transmitted to the main shaft 12.

The continuously variable transmission 4 has a main shaft 12 and a sub-shaft 13 arranged parallel to the main shaft 12. The main shaft 12 has a variable-boot interval primary pulley 14 equipped with a hydraulic cylinder 14a.
A secondary pulley 15 is similarly provided with a hydraulic cylinder 15a. Further, a drive belt 16 is wound around both pulleys 14 and 15, and both cylinders 14a and 15a are connected to each other.
is configured in the hydraulic control circuit 17. Line pressure corresponding to the transmission torque is supplied to both cylinders 14a and 15a to apply a pulley pressing force, and the primary pressure causes the primary pulley 14. of the drive belt 16 to be pressed. The winding around the secondary pulley 15 is configured to change the ratio of diameters to perform stepless speed change control.

Next, the electronic control system of the electromagnetic powder clutch 2 and the continuously variable transmission 4 will be explained. Engine speed sensor 19 for engine 1. Rotational speed sensors 21 and 22 for the primary pulley and secondary pulley of the continuously variable transmission 4 have sensors 23 and 24 for detecting the operating status of the air conditioner and choke. Further, the shift lever 25 of the operating system is mechanically connected to the forward/reverse switching device 3, and is set to reverse (R), drive (D).
, and has a shift position sensor 26 that detects each range of sporty drive (Ds). Furthermore, accelerator pedal 2
7 has an accelerator switch 28 for detecting the accelerator depression state, and a throttle opening sensor 2 on the throttle valve side.
It has 9.

The various signals from the switches and sensors are input to the electronic control unit 20 and processed by software using a microcomputer or the like. Then, the clutch control signal output from the electronic control unit 20 is input to the electromagnetic powder clutch 2, and the shift control signal and line pressure control signal are input to the hydraulic control circuit 17 of the continuously variable transmission 4 to perform each control operation. It has become.

In FIG. 2, the electromagnetic clutch control system of the control unit 20 will be mainly explained.

First, the signals of the primary pulley rotation speed Np, secondary pulley rotation speed Ns, shift positions R, D, Ds, and throttle opening θ from the sensor 21.22.26.29 are input to the shift speed control section 30, and A control signal corresponding to the speed di/dt is output. Also, the engine rotation speed Ne and the throttle opening degree θ of the sensor 19.

The signal of the actual speed ratio 1 (N S / N p) is input to the line pressure control section 31, which outputs a control signal according to the target line pressure. These control signals are input to the continuously variable transmission 4 to control the line pressure to a predetermined level and to control the speed change.

The electromagnetic clutch control system includes a reverse excitation mode determination unit 32 in which parking (P) and neutral (N) signals other than the engine speed Ne and R, D, and Ds of the shift position sensor 26 are manually operated. e < 300rp
11, or in the case of P or N range, it is determined to be the reverse excitation mode, and the output determination section 33 causes a minute current to flow in the opposite direction to the normal one. Then, the residual magnetism of the electromagnetic powder clutch 2 is removed and it is completely released.

Also, the determination output signal of this reverse excitation mode determination section 32.

It has an energization mode determination section 34 that receives the depression signal of the accelerator switch 28 and the vehicle speed V signal of the secondary boot rotation speed sensor 22, and determines the driving state such as starting, and this determination signal is used to determine whether the starting mode, drag mode, or Input to each current setting section 35.36°37 in direct connection mode.

The starting mode current setting unit 35 separately sets starting characteristics in relation to the engine rotation speed number and the like in the case of normal starting or starting using an air conditioner or a choke. Then, throttle opening θ and vehicle speed V.

The clutch current is set by correcting the starting characteristics according to each driving range of R, D, and Ds. The drag mode current setting unit 36 determines a slight drag current when the accelerator is released at low vehicle speed in each of the R, D, and Ds ranges, and generates drag torque in the electromagnetic powder clutch 2 to reduce play in the belt and drive system. to ensure a smooth start. In this mode, the current is set to zero until just before the vehicle stops after the clutch is released in the D range, to ensure coasting performance. The direct-coupling mode current setting unit 37 determines the direct-coupling current based on the relationship between the vehicle speed V and the throttle opening θ in each range of R, D, and Ds, and fully engages the electromagnetic powder clutch 2 to save power in the engaged state. I do. The output signals from these current setting units 35, 38, 87 are input manually to the output determining unit 33, and the clutch current is determined according to the instructions thereof, and the map of each mode is as shown in FIG.

In the electromagnetic clutch control system described above, a clutch temperature detection means 4o is provided in the circuit of the clutch coil 2c to prevent burnout of the clutch at the time of starting.

That is, the clutch coil 2c has a circuit configuration such that the clutch current is controlled via the drive means 38 according to an instruction from the output determination section 33, and a coil terminal voltage detection section 41 is installed at both ends of the clutch coil 2c. Connected so as to detect the inter-terminal voltage Vc from the voltage difference. Further, a current detection resistor 42 is connected in series to the clutch coil 2c, and a coil current detection section 43 is connected to both ends of the current detection resistor 42. The current 1c is detected. Coil voltage Vc of these coil terminal voltage detection sections 41.

The coil current Ic of the coil current detection section 43 is input to the coil temperature calculation section 44, and the coil resistance Rc (V e/I c
).

Coil temperature Tc is calculated using the following formula using coil temperature coefficient α and coil resistance RO at a predetermined temperature To.

Re −RO[l+(Z (Tc −To )1) The above coil temperature Tc is manually input to the clutch overheating determination unit 45 and compared with, for example, the coil limit temperature TL, and if Te≧TL, the energization mode determination unit 34 selects the direct connection mode. is configured to output a switching signal.

Next, the operation of the control device configured in this way is explained in the fourth section.
This will be described using the flowchart shown in the figure and the time charts shown in Figs. 5(a) and 5(b).

First, when shifting to the driving range and starting by depressing the accelerator 27, the starting mode current setting section 35 is selected by the energization mode determining section 34 in the electromagnetic clutch control system. Therefore, the engine speed Ne as shown in Fig. 5(a)
The clutch current Ic is controlled to gradually rise as shown in (b) in response to the rise in the output determination section 33. The clutch coil 2C is driven by the drive means 38.
, and a corresponding clutch torque is generated. Therefore, the engine power is transmitted to the driven member 2b and subsequent parts of the electromagnetic powder clutch 2 according to the clutch torque to start driving.In this case, in the case of a dry road surface, etc., the brake rotation speed Np on the clutch output side is As shown by the solid line in FIG. 5(a), the clutch torque (clutch current) increases due to the characteristics of the road gap, and the vehicle speed V also increases as shown by the solid line. And the engine rotation speed Ne and the primary pulley rotation speed Np
matches relatively quickly, and the third
When the vehicle speed V2 shown in the diagram is reached, the energization mode determination unit 34
The direct connection mode current setting section 37 is selected. Therefore, from this point on, a direct coupling current IL as shown in FIG. 5(b) flows through the clutch coil 2C, and the electromagnetic powder clutch 2 is maintained in an engaged state. In this way, the electromagnetic powder clutch 2 has the engine rotational speed Na and the primary pulley rotational speed N.
Engagement control is performed smoothly so that p is synchronized with p.

On the other hand, at the time of starting, the clutch temperature detection means 40 detects the clutch temperature T based on the flowchart of FIG.
c is directly detected without being affected by the outside temperature, and the clutch overheating determining section 45 determines the overheating state of the clutch.

During the above-mentioned normal start, there is little slippage and less heat generation, and the clutch temperature Te and coil limit temperature TI are equal to Tc.
<TI, the above-mentioned energization mode is established.

Next, when the wheels get stuck when starting on a snowy road or the like, even if the clutch torque is generated as described above by the clutch current 1c, the primary pulley rotation speed Np is low as shown by the broken line in FIG. 5(a). Therefore, the slip region due to the rotational difference between the engine rotational speed Ne and the primary pulley rotational speed Np expands, leading to an increase in clutch heat generation, which is detected by the clutch temperature detection means 40 as described above, and the clutch temperature Te and the coil limit temperature TL are Tc≧T
At time point L, the clutch overheating determining section 45 forcibly switches the energization mode determining section 34 to the direct coupling mode. Therefore, the electromagnetic powder clutch 2 is immediately engaged and held by the direct current as shown by the broken line in FIG. 5(b), and the engine speed Ne decreases as shown by the broken line in FIG. 5(a) while the primary pulley The rotational speed coincides with the rotational speed Np, and from this point on, slipping and heat generation no longer occur. In this way, the electromagnetic powder clutch 2 is prevented from generating heat and burnout is prevented, and as the electromagnetic powder clutch 2 is engaged, the vehicle speed V also increases as indicated by the dashed line as the vehicle travels.

According to another embodiment of the present invention shown in FIG.
1 to v2 have a comparing section 84b which is manually operated. Therefore, a correction section 46 is provided on the output side of the direct-coupled vehicle speed setting section 34a, and is configured to correct the direct-coupled vehicle speed 2 to a lower value v'2 based on the output signal of the clutch overheat determining section 45.

Therefore, in this embodiment, when the clutch is overheated, the directly connected vehicle speed v′
2, a switching signal is output from the comparison section 34b to the switching section 34c, and the mode is switched to the direct connection mode in the same manner as described above.

Note that the present invention can be applied to other than electromagnetic clutches. Further, the clutch temperature may be estimated based on the internal temperature of the clutch, or may be detected by attaching a temperature sensor to the clutch side.

〔Effect of the invention〕

As described above, according to the present invention, since the clutch temperature is directly detected in automatic clutch start control, burnout can be reliably prevented and shocks caused by clutch engagement can be minimized. .

Furthermore, when there is a risk of clutch burnout, the start mode is immediately switched to the direct connection mode and the clutch is engaged and held, so that heat generation can be effectively prevented and running performance is also ensured.

In addition, the control for correcting the reduction in the directly coupled vehicle speed can be easily performed using a normal mode flowchart or the like.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an example of an automatic clutch to which the present invention is applied, FIG. 2 is a block diagram of a control system, FIG. 3 is a diagram showing clutch operation modes, FIG. 4 is a flowchart of the operation, FIG. 5(a) is a characteristic diagram at the time of starting, FIG. 5(b) is a clutch current characteristic diagram, and FIG. 6 is a block diagram of another embodiment of the present invention. 2... Electromagnetic powder clutch, 20... Electronic control unit, 34... Energization mode determination section, 35... Starting mode current setting section, 37... Direct connection mode current setting section, 40
...Clutch temperature detection means

Claims (1)

[Scope of Claims] In a start control system that sets at least a predetermined direct-coupling vehicle speed and holds the clutch in an engaged state in a direct-coupling mode after reaching the direct-coupling vehicle speed, a clutch that directly detects the temperature of the clutch; It has a temperature detection means, sets a direct coupling vehicle speed lower than normal in the control system of the direct coupling mode, and when the temperature of the clutch according to the clutch temperature detection means exceeds the set temperature, the clutch is switched to the direct coupling mode. A control device for an automatic clutch for a vehicle, characterized in that the direct coupling mode is determined at a low direct coupling vehicle speed.