JP2549844B2 - Automatic clutch control system for vehicles - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to an automatic clutch control device that is provided in a drive system of a vehicle and electronically controls clutch torque, and more particularly, to clutch torque control when the clutch is overheated. The applicant of the present application has already proposed a large number of automatic clutches for vehicles of this type, for example, those intended for electromagnetic clutches. Most of them are transient states such as when starting,
In the steady state after the clutch is directly connected, the clutch torque is optimally controlled in relation to the operation of the accelerator pedal or shift lever, the running condition, the engine state, etc., and further in combination with the manual transmission or the belt type continuously variable transmission. This is to perform suitable control. Particularly in recent years, electronic control of not only the engine but also the clutch of the drive system, the transmission and the like has been advanced, and even automatic clutches tend to be controlled more finely.

[Prior art]

Conventionally, regarding the above-mentioned vehicle automatic clutch, for example, there is a prior art of Japanese Patent Application Laid-Open No. 60-161224, and it is shown that various running modes are determined and clutch control is performed by selecting a mode depending on an engine operating state or a running state. ing. Regarding clutch overheating, for example, Japanese Patent Laid-Open No. 58-163
There is the prior art of Japanese Patent No. 831, and there is shown a device for directly detecting the temperature rise of the coil from the values of voltage and current applied to the coil.

[Problems to be Solved by the Invention]

In the electromagnetic clutch, if the temperature of the clutch coil rises abnormally, there is a risk of causing problems such as burnout, so it is necessary to monitor the temperature accurately. In this respect, the latter detection method of the above-mentioned prior art is effective. . On the other hand, the clutch torque control when the clutch is overheated is as important as the temperature detection, and when clutch control is performed by setting various running modes like the former of the above-mentioned prior art, the control in each running mode is performed. It is necessary to take measures to prevent overheating. The present invention has been made in view of the above circumstances, and provides a control device for an automatic clutch for a vehicle, which monitors the clutch temperature and, when overheated, appropriately takes preventive measures against overheating in each control region. It is an object.

[Means for solving problems]

As means for achieving this object, the present invention relates to a vehicle automatic clutch control device including clutch torque control means for controlling a released state, a direct connection state, and a half-clutch state of the clutch, wherein the clutch torque control means is a clutch. Starting torque setting means for reducing the clutch slip amount by correcting the clutch torque characteristic in the half clutch state at the time of starting to a high rate of increase in response to an increase in the clutch temperature based on the detection signal from the temperature detecting means, and the clutch temperature When the vehicle starts moving from the half-clutch state to the direct-connection state, the direct-connection vehicle speed is corrected to the low speed side to reduce the half-clutch region, and the accelerator release in the direct-connection state according to the increase in the clutch temperature. The clutch torque characteristics during the transition period from transition to depression Characterized in that it comprises a transient torque setting means for decreasing the up amount.

[Action]

In the present invention employing such means, in response to an increase in the clutch temperature, the clutch slip amount in the half-clutch state at the time of starting is reduced, and the half-clutch region at the time of starting until the shift to the direct connection state is reduced. Since the clutch slip amount during the transition period from the accelerator release in the direct connection state to the depression is reduced, the heat generation amount of the clutch is comprehensively reduced.

【Example】

Embodiments of the present invention will be described below with reference to the drawings. Referring to FIG. 1, an overall structure of a drive system in which an electromagnetic clutch is combined with a belt type continuously variable transmission will be described. The engine 1 is connected to a continuously variable transmission 4 via an electromagnetic powder type clutch 2 and a forward / reverse switching device 3, and a set of reduction gears 5, an output shaft 6, a differential gear 7 and an axle 8 are connected to the continuously variable transmission 4. Is configured to be transmitted to the drive shaft 9 via. 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 having a clutch coil 2c. And clutch coil 2c
Electromagnetic powder is coupled and accumulated in a gap between the members 2a and 2b in a chain shape by a clutch current flowing therethrough, and clutch engagement / disengagement and clutch torque are variably controlled by the resulting coupling force. The forward / reverse switching device 3 is configured to be in a synchronous mesh type between the input shaft 11 and the transmission main shaft 12 by a gear, a hub, and a sleeve, and has at least a forward position where the input shaft 11 is directly connected to the main shaft 12 and an input shaft. And a retracted position where the rotation of 11 is reversed and transmitted to the main shaft 12. The continuously variable transmission 4 includes a main shaft 12 and an auxiliary shaft arranged in parallel with the main shaft 12.
The main shaft 12 is provided with a primary pulley 14 having a hydraulic cylinder 14a and a variable pulley distance, and the auxiliary shaft 13 is similarly provided with a secondary pulley 15 having a hydraulic cylinder 15a. A drive belt 16 is wound around both pulleys 14 and 15, and both cylinders 14a and 15a are configured in a hydraulic control circuit 17. Then, a 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 changes the ratio of the winding diameter of the drive bell 16 to the pulleys 14 and 15 to continuously change the speed. Is configured to control. Next, an electronic control system for the electromagnetic powder clutch 2 and the continuously variable transmission 4 will be described. It has an engine speed sensor 19 of the engine 1, primary and secondary pulley speed sensors 21, 22 of the continuously variable transmission 4, and sensors 23, 24 for detecting the operating conditions of an air conditioner and a choke. Further, the shift lever 25 of the operation system is mechanically coupled to the forward / reverse switching device 3, and a shift position sensor 26 for detecting each range of reverse (R), drive (D), and (sporty drive (Ds)). Further, the accelerator pedal 27 has an accelerator switch 28 for detecting an accelerator pedal depression state, a throttle opening sensor 29 on the throttle valve side, and a rotation speed sensor 18 on the clutch driven side. Various signals of switches and sensors are input to the electronic control unit 20 and processed by software using a microcomputer etc. Then, the clutch control signal output from the electronic control unit 20 is transmitted to the electromagnetic powder type clutch 2 to change gears. The control signal and the line pressure control signal are input to the hydraulic control circuit 17 of the continuously variable transmission 4 to perform each control operation. The electromagnetic clutch control system of the control unit 20 will be mainly described.First, the primary pulley rotation speed Np, of the sensors 21, 22, 29,
The signals of the secondary pulley rotation speed Ns and the throttle opening θ are input to the speed change control unit 30, and control signals corresponding to the speed change di / dt are output. The signals of the engine speed Ne of the sensor 19, the throttle opening θ, and the actual gear ratio i (Ns / Np) are input to the line control unit 31 and a control signal corresponding to the target line pressure is output. Then, these control signals are input to the continuously variable transmission 4 to control the line pressure to a predetermined value and to control the shift. The clutch control system has a reverse excitation mode determination unit 32 to which signals of the engine speed Ne and the traveling range of R, D, Ds of the shift position sensor 26 are input. For example, when Ne <300 rpm, or when the parking (P ), In the case of the neutral (N) range, the reverse excitation mode is determined, and the cylinder determination unit 33 causes a minute current in the opposite direction to the normal direction to flow. Then, the electromagnetic powder type clutch 2 is completely released except the residual magnetism. Also,
The energization mode determination unit 34 to which the determination cylinder signal of the reverse excitation mode determination unit 32, the depression signal of the accelerator switch 28, and the vehicle speed V signal of the secondary pulley rotation speed sensor 22 are input.
Has, and determines the running state at the time of starting, this determination signal,
Input to each current setting unit 35, 36, 37 in the start mode, the drag mode, and the direct connection mode of the steady mode. The start mode current setting unit 35 sets the start characteristics separately in relation to the engine speed Ne and the like in the case of a normal start or a start using an air conditioner or a choke. Then, the starting characteristic is corrected by each running range of the throttle opening θ and the vehicle speed V, R, D, Ds, and the clutch current is set. The drag mode current setting unit 36 determines a minute drag current when the accelerator is released at a low vehicle speed in each range of R, D, Ds,
A belt is generated by applying drag torque to the electromagnetic powder clutch 2.
The drive system is squeezed to ensure a smooth start. Further, in this mode, the current is set to zero until just before the vehicle is stopped after the clutch in the D range is released to ensure coasting. The direct connection mode current setting unit 37 determines the direct connection current according to the relationship between the vehicle speed V and the throttle opening θ in each range of R, D, Ds, fully engages the electromagnetic powder clutch 2, and saves power in the engaged state. I do. The output signals of the current setting units 35, 36, 37 are input to the output determination unit 33, and the clutch current is determined according to the instruction, and the map of each mode is as shown in FIG. Further, when switching the mode of the steady mode, as a transient mode control such as an accelerator operation and a gear shift operation, a clutch engagement rate calculation unit to which the engine speed Ne of the clutch input side and the clutch driven speed Nc of the clutch output side are input. Has 38. Here, the engagement ratio E is calculated by E = Nc / Ne, and when E = 1, the clutch is directly connected. On the other hand, in the engine drive of Ne> Nc, the slip state occurs when E <1, and in the wheel drive of Nc> Ne the slip state occurs when E> 1. On the other hand, for each of the start, drag, and direct connection mode current setting units 35, 36, and 37, a transient mode current setting unit 39 to which the determination result of the energization mode determination unit 34 is similarly input is provided to determine which transient mode. To do. This transient mode current setting section 39
Is the clutch engagement rate E and clutch driven speed N
The respective signals of c and the throttle opening θ are input, and the clutch current is set so that the engagement rate E matches the target engagement rate E ₀ during engine or wheel drive. Measures for overheating the clutch in the clutch control system will be described. First, the clutch temperature detection means will be described. The clutch temperature detection means has detection sensors 40 and 41 for detecting a voltage Ec (V) applied to the electromagnetic powder type clutch 2 and a current Ic (A) at that time. It is input to the temperature calculation unit 42 to calculate the clutch temperature t (° C). That is, assuming that the coil resistance at t ₀ (° C.) is R ₀ (Ω), the clutch temperature t is calculated from the equation of the temperature gradient of the copper wire resistance as follows. t = {(Ec / Ic-R ₀ ) / R ₀ } × (234,45 + t ₀ ) + t ₀ (° C) Thus, the coil temperature is directly detected based on the change in the resistance value of the clutch coil. If it is high, it is judged as overheating. The output signal of the clutch temperature calculation unit 42 is input to one of the various modes for half-clutch control, that is, each of the current setting units 35 and 39 in the start and transition modes and the energization mode determination unit 34. Then, the characteristics in each mode are changed according to the clutch temperature so as to reduce to the slip region when overheated. Next, the operation of the control device configured as described above will be described with reference to characteristic diagrams such as FIGS. 4 (a) and 4 (b). First, for example, when shifting to the D range and depressing the accelerator, the start mode current setting unit 35 is selected to enter the start mode, and a clutch current proportional to the engine speed flows as shown in FIG. 4 (a). The clutch torque gradually increases. Therefore, when an overheat signal is input from the clutch temperature calculation unit 42 at the time of starting the vehicle, the characteristic is corrected to have a high rate of increase in proportion to the clutch temperature, and the clutch slip amount and the half-clutch region are reduced during overheating. When the clutch is overheated at the time of switching from the start mode to the direct connection mode, the energization mode determination unit 34 shifts the direct connection vehicle speeds V ₃ ′ and V ₄ ′ to the low speed side as indicated by the broken line in FIG. As a result, the clutch is directly connected on the low speed side. On the other hand, in the direct connection mode selected by the direct connection mode current setting unit 37, when the direct connection current changes from I _LL to I _LH due to depression from accelerator release as shown in FIG. The setting unit 39 is selected to control the clutch engagement rate E. Therefore, at this time, when the clutch temperature signal is input, the target engagement rate E ₀ is corrected to a value close to 1 in proportion to the clutch temperature, whereby the direct coupling current I _LH rises earlier and the same as above. It reduces the slip area. Although one embodiment of the present invention has been described above, the present invention is not limited to this.

【The invention's effect】

As described above, according to the present invention, as the clutch temperature rises, the clutch slip amount in the half-clutch state at the start decreases, and the half-clutch region at the start until the shift to the direct connection state decreases. In this state, the clutch slip amount during the transition period from the accelerator release to the depression is reduced, so that the heat generation amount of the clutch can be comprehensively reduced to ensure the running of the vehicle and reliably prevent the clutch from burning. it can.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of a control device of the present invention, FIG. 2 is an overall block diagram of an electronic control system, FIG. 3 is a map diagram of each mode, and FIG. 4 (a), ( FIG. 7B is a diagram showing a reduced state of the slip area. 2 ... Electromagnetic powder clutch, 20 ... Electronic control unit, 34
...... Energization mode determination unit, 36 ...... Starting mode current setting unit,
37: Transient mode current setting unit, 42: Clutch temperature calculation unit.

Claims (1)

(57) [Claims] 1. A vehicle automatic clutch control device comprising clutch torque control means for controlling a released state, a direct connection state, and a half-clutch state of a clutch, wherein the clutch torque control means is detected by a clutch temperature detection means. A starting torque setting means for reducing the clutch slip amount by correcting the clutch torque characteristic of the half-clutch state at the time of starting according to the signal based on the signal to a high rate of increase, and at the time of starting according to the increase in the clutch temperature. The direct connection torque determination means for reducing the half clutch area by correcting the direct connection vehicle speed that shifts from the half clutch state to the direct connection state to the low speed side, and the transition from the accelerator release to the depression in the direct connection state in response to the increase in the clutch temperature. Of the transient torque to reduce the clutch slip amount by correcting the clutch torque characteristic of Control apparatus for an automatic clutch for a vehicle, characterized in that it comprises a setting means.