JP2002130338A - Friction clutch control unit of driving device for automotive vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a friction clutch control unit of driving device for automotive vehicle in which a sharp decline of transmission torque of a hydraulic coupling when a vehicle backs up in the slope can be prevented by controlling in such a way that a velocity ratio of the hydraulic coupling becomes larger than the specified value with a friction clutch being turned into half clutch status when the velocity ratio of the hydraulic coupling is lowered below the predetermined value which is set less than zero (0). SOLUTION: The friction clutch control unit of the driving device for the automotive vehicle comprises an engine mounted on the vehicle, the hydraulic coupling operated by the engine, and the friction clutch arranged between the hydraulic coupling and a speed change gear, wherein a velocity ratio between a pump rotational speed and a turbine rotational speed of the hydraulic coupling is obtained and then a clutch operating means is so controlled that the friction clutch is brought into the half clutch status when the velocity ratio is lowered below the predetermined value set lower than zero (0).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a vehicle drive device,
More specifically, the present invention relates to a friction clutch control device of a vehicle drive device that transmits a driving force of an engine to a transmission via a fluid coupling and a friction clutch.

[0002]

2. Description of the Related Art As shown in FIG. 3, an engine 2, a fluid coupling 3 operated by the engine 2, and a friction clutch 4 disposed between the fluid coupling 3 and a transmission 4 are provided. Vehicles equipped with a vehicle drive device have been put into practical use. In such a vehicle, as shown in FIG. 3, the engine 2 is operated on an uphill slope R having a large gradient, the transmission 5 is shifted to the forward gear, and the friction clutch 4 is connected. In this case, the pump 32 and the turbine 33 of the fluid coupling 3 rotate in opposite directions. That is, the pump 32 of the fluid coupling 3 is driven forward by the engine 2, but is rotated forward, whereas the turbine 33 of the fluid coupling 3 is driven reversely from the wheels W with the retreat of the vehicle, so that the turbine 33 is reversed.

Here, the relationship between the rotational speed difference (speed ratio) between the pump 32 and the turbine 33 of the fluid coupling 3 and the transmission torque will be described. In the fluid coupling 3 in which the impeller of the pump 32 and the runner of the turbine 33 are both straight blades and the blade angle is 0 degree, that is, the radially structured fluid coupling 3, the relationship between the speed ratio (e) and the transmission torque capacity coefficient (τ) is shown in FIG. It looks like 4. In FIG. 4, a speed ratio (e) between 0 and 1 is a normal traveling region where the vehicle drive device shown in FIG. 3 is driven by the engine 2, and a region where the speed (e) is 1 or more is the wheel W This is an engine brake region where the engine 2 is driven from the side, that is, the transmission 5 side. The region where the speed ratio (e) is 0 or less is a region where the pump 32 and the turbine 33 of the fluid coupling 3 rotate in directions opposite to each other. The region where the speed ratio (e) is 0 or less is shown in FIG.
As shown in FIG. 5, when the engine 2 is operated on a steep ascending slope to shift the transmission 5 to the forward gear and the friction clutch 4 is connected, and the vehicle moves backward due to gravity, the pump 32 of the fluid coupling 3 This region is driven in the forward direction by the engine 2 and driven in the reverse direction because the turbine 33 of the fluid coupling 3 is driven from the wheel W side as the vehicle retreats.

[Problems to be solved by the invention]

In the above-mentioned fluid coupling, the speed ratio (e)
Is in the range of 0 to -1 (the range in which the absolute value of the pump rotation speed is higher than the absolute value of the turbine rotation speed), and the fluid in the fluid coupling is in normal running (the speed ratio (e) is in the range of 0 to 1). Turn in the same direction. For this reason, the torque of the fluid coupling acts in the normal rotation direction. However, when the speed ratio (e) is -1, that is, when the absolute value of the rotation speed (forward rotation) of the pump and the absolute value of the rotation speed (reverse rotation) of the turbine are the same, the centrifugal force applied to the fluid by the pump and the turbine becomes equal, and the fluid coupling No swirling motion occurs in the fluid inside. As a result, as shown in FIG.
When it is 1, the transmission torque capacity coefficient (τ) of the fluid coupling becomes zero (0), and the transmission torque of the fluid coupling becomes zero (0). Therefore, when the vehicle retreats due to gravity on a steep ascending slope as shown in FIG. 3, the transmission torque suddenly decreases from a speed ratio (e) of the fluid coupling near -0.5 as shown in FIG. When the speed ratio (e) becomes −1, the transmission torque becomes zero (0), and there is a possibility that the reversing speed of the vehicle may further increase. Further, when the accelerator pedal is depressed in such a state to accelerate the vehicle, the increase speed of the turbine rotation speed and the increase speed of the engine rotation speed with the increase in the reverse vehicle speed may become equal. In this case, the speed ratio (e) of the fluid coupling is maintained at -1, and the torque transmission of the fluid coupling continues to be zero (0) even though the engine rotation speed is increasing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and its main technical problem is that when the speed ratio of a fluid coupling is equal to or less than a predetermined value smaller than zero (0), the friction clutch is brought into a half-clutch state. By controlling the speed ratio of the fluid coupling to be greater than a predetermined value, a friction clutch control device for a vehicle drive device capable of preventing a sudden decrease in the transmission torque of the fluid coupling when the vehicle retreats on a hill. To provide.

[0006]

According to the present invention, in order to solve the above-mentioned main technical problems, an engine mounted on a vehicle, a fluid coupling operated by the engine, the fluid coupling and a transmission are provided. And a friction clutch disposed between the fluid coupling, a pump rotational speed detecting means for detecting a rotational speed of a pump of the fluid coupling, and a rotational speed and a rotational direction of a turbine of the fluid coupling. Turbine rotation speed detecting means for detecting, clutch operating means for disconnecting / engaging the friction clutch, and controlling the clutch operating means based on detection signals from the pump rotation speed detection sensor and the turbine rotation speed detection sensor Control means for determining a speed ratio between the pump rotation speed and the turbine rotation speed, wherein the speed ratio is smaller than zero (0). In the following situations, the friction clutch for controlling the clutch actuation means so that the half clutch state, the friction clutch control device of a vehicle drive apparatus is provided, characterized in that.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a friction clutch control device in a vehicle drive device constructed in accordance with the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a friction clutch control device for a vehicle drive device configured according to the present invention. The illustrated vehicle drive device includes an engine 2 as a prime mover such as a diesel engine, a fluid coupling (fluid coupling) 3, a wet multi-plate friction clutch 4, and a manual transmission 5, which are connected in series. It is arranged.

The fluid coupling 3 in the illustrated embodiment includes a casing 31, a pump 32 and a turbine 33, and the casing 31 is connected to the crankshaft 21 of the engine 2.
It is attached to.

The pump 32 has a bowl-shaped pump shell 321.
And a plurality of impellers 322 radially arranged in the pump shell 321.
1 is attached to the casing 31 by fixing means such as welding. Therefore, the pump shell 321 of the pump 32 is connected to the crankshaft 21 of the engine 2 via the casing 31. For this reason, the crankshaft 21 functions as an input shaft of the fluid coupling 3.

The turbine 33 is disposed in a chamber formed by the pump 32 and the casing 31 so as to face the pump 32. The turbine 33 includes a bowl-shaped turbine shell 331 disposed to face the pump shell 321 of the pump 32, and a plurality of runners 332 radially disposed in the turbine shell 331. . The turbine shell 331 has an output shaft 34 disposed on the same axis as the crankshaft 21 as an input shaft of the fluid coupling 3.
Attached to.

Next, the wet multi-plate friction clutch 4 will be described. The wet multi-plate friction clutch 4 includes a clutch outer 41 provided on the same axis as the output shaft 34 of the fluid coupling 3 and a clutch center 42 provided on the same axis as the clutch outer 41. ing. The clutch outer 41 is formed in a drum shape, and a hub 411 connected to the output shaft 34 of the fluid coupling 3 is provided on an inner peripheral portion thereof. An internal spline 412 is provided on the inner surface of the outer peripheral portion of the clutch outer 41, and a plurality of friction plates 43 are fitted to the internal spline 412 so as to be slidable in the axial direction. An annular cylinder 44 is formed in an intermediate portion of the clutch outer 41, and a pressing piston 45 for pressing the friction plate 43 and a friction plate 47 described later is disposed in the annular cylinder 44. I have. A hydraulic chamber 46 formed by the annular cylinder 44 and the pressing piston 45 communicates with a hydraulic operating circuit 6 as a clutch operating means described later.

The clutch center 42 is formed in a disk shape, and a hub 421 connected to the input shaft 51 of the transmission 5 is provided on an inner peripheral portion thereof. An external spline 422 is provided on the outer peripheral surface of the clutch center 42, and a plurality of friction plates 47 are fitted to the external spline 422 so as to be slidable in the axial direction. A plurality of friction plates 47 mounted on the clutch center 42 and the clutch outer 41
And a plurality of friction plates 43 mounted on each of them are arranged alternately.

The wet multi-plate friction clutch 4 in the illustrated embodiment is constructed as described above, and when the hydraulic oil is not supplied to the hydraulic chamber 46 by the hydraulic operating circuit 6 as a clutch operating means described later, a plurality of clutches are provided. Since the plurality of friction plates 43 and the plurality of friction plates 47 are not pressed, the plurality of friction plates 43 and the plurality of friction plates 47 do not frictionally engage with each other. Input shaft 51
The power transmission to is shut off. When hydraulic oil is supplied to the hydraulic chamber 46 by a hydraulic operating circuit 6 described later, the pressing piston 45 is moved rightward in FIG. As a result, the plurality of friction plates 43 and the plurality of friction plates 47 are pressed and frictionally engaged with each other, so that the power transmitted to the output shaft 34 of the fluid coupling 3 is transmitted to the clutch outer 41 and the plurality of friction plates 43. , 47 and the clutch center 42 to the input shaft 51 of the transmission 5.

Next, the hydraulic operating circuit 6 as the clutch operating means will be described. The hydraulic operation circuit 6 includes a reserve tank 61 for storing hydraulic oil, and the hydraulic oil in the reserve tank 61 is sucked up by the hydraulic pump 62 through the passage 63 and discharged to the passage 64. The hydraulic oil discharged to the passage 64 is supplied to the hydraulic chamber 46 of the wet multi-plate friction clutch 4 through the passage 65. An electromagnetic switching valve 67 (V1) is provided between the passage 64 and the passage 65. The electromagnetic switching valve 67 (V1) is in the state of the passage 64 when deenergized (OFF) in the state shown in FIG.
And the passage 65 is interrupted and the passage 65 returns to the return passage 6.
The passage 64 communicates with the passage 65 when the passage 64 is energized (ON). The duty of the electromagnetic switching valve 67 (V1) is controlled in the illustrated embodiment. The duty ratio (R) for this duty control is divided from 0 to 100,
When the duty ratio (R) is 0, the OFF state is maintained, and as the duty ratio (R) increases (closer to 100).
ON time becomes longer. Therefore, as the duty ratio (R) increases, the pressure in the hydraulic chamber 46 increases, and the transmission torque of the clutch increases.

The illustrated friction clutch control device includes an engine speed sensor 7 for detecting the speed of the engine 2. In the illustrated embodiment, the engine rotation speed detection sensor 7 functions as a pump rotation speed detection unit that detects the rotation speed of the pump 32 of the fluid coupling 3 connected to the crankshaft 21 of the engine 2. Further, the illustrated friction clutch control device includes a clutch input element rotational speed detection sensor 8 for detecting the rotational speed of the clutch outer 41 of the wet multi-plate friction clutch 4. In the illustrated embodiment, the clutch input element rotational speed detection sensor 8 includes a clutch outer 41 and an output shaft 3.
4 functions as turbine rotation speed detection means for detecting the rotation speed of the turbine 33 of the fluid coupling 3 to which the connection has been made. When the rotation direction of the turbine 33 is the same as the rotation direction (forward rotation) of the pump 32, the rotation speed of the turbine 33 is positive (+), and the rotation direction of the turbine 33 is In the case of the rotation direction (forward rotation), the rotation speed becomes a negative (-) value. Therefore, the turbine rotation speed detecting means in the illustrated embodiment has a function of detecting the rotation direction of the turbine 33. Furthermore,
The illustrated friction clutch control device includes a clutch output element rotation speed detection sensor 9 for detecting the rotation speed of the input shaft 51 of the transmission 5 connected to the clutch center 42 of the wet multi-plate friction clutch 4. Further, the illustrated friction clutch control device includes an accelerator pedal sensor 11 for detecting a depression amount of an accelerator pedal 10 for adjusting the load of the engine 2. This accelerator pedal sensor 11
Functions as an accelerator opening detecting means for detecting the load on the engine 2 in the illustrated embodiment. Each of these sensors outputs a detection signal to a control unit 20 described later.

The friction clutch control device in the illustrated embodiment has a control means 20. Control means 20
Is a central processing unit (CP) configured by a microcomputer and performing arithmetic processing according to a control program.
U) 201, a read-only memory (ROM) 202 for storing control programs and the like, and a readable and writable random access memory (RAM) 203 for storing calculation results and the like
And an input interface 204 and an output interface 205. The input interface 204 of the control means 20 having the above-described configuration includes detection signals from the engine rotation speed detection sensor 7, the clutch input element rotation speed detection sensor 8, the clutch output element rotation speed detection sensor 9, the accelerator pedal sensor 11, and the like. Is entered. The output interface 205 outputs a control signal to the electromagnetic switching valve 67 (V1).

The vehicle drive device in the illustrated embodiment is configured as described above, and the driving force of the engine 2 is transmitted to the manual transmission 5 via the fluid coupling 3 and the wet multi-plate friction clutch 4. Next, an operation procedure of the control means 20 in the friction clutch control device of the above-described vehicle drive device will be described with reference to a flowchart shown in FIG. The control means 20 firstly controls the pump rotation speed (ω) detected by the engine rotation speed detection sensor 7 in step S1.
A ratio between 1) and the turbine rotation speed (ω2) detected by the clutch input element rotation speed detection sensor 8, that is, a speed ratio (e) is obtained (e = ω2 / ω1). The fluid coupling 3
Is a positive (+) value when the rotation direction of the turbine 33 is the same as the rotation direction (forward rotation) of the pump 32, and the rotation direction of the turbine 33 is the rotation speed of the pump 32. In the case of the direction opposite to the direction (forward rotation), the value is negative (-). In step S1, the speed ratio (e) of the fluid coupling 3
Is obtained, the control means 20 proceeds to step S2 to check whether the speed ratio (e) is equal to or more than a predetermined value. This predetermined value is a value smaller than zero (0) (the speed ratio in the region where the pump and turbine of the fluid coupling rotate in opposite directions in FIG. 4 showing the relationship between the speed ratio (e) and the transmission torque capacity coefficient (τ)). In (e)), in the illustrated embodiment, the transmission torque is set to -0.5, at which the transmission torque starts to decrease rapidly.

In step S2, the speed ratio (e) is set to -0.0.
When the speed is 5 or less, the control means 20 determines that the turbine 33 of the fluid coupling 3 is in the reverse rotation state, the vehicle operates the engine 2 on the uphill as shown in FIG. When the wet multi-plate friction clutch 4 is connected (duty ratio (R) is 100), it is determined that the clutch is retracted by gravity, and the process proceeds to step S3 to control the duty of the electromagnetic switching valve 67 (V1). (R = R + (e + 0.5))
XC). In the equation for calculating the duty ratio (R), C is a positive constant. That is, the duty ratio (R)
Is calculated by adding 0.5 to the speed ratio (e) obtained in step S1 to the previous duty ratio (R), and adding a value obtained by multiplying the sum by a constant C. The duty ratio (R)
In the formula for calculating, 0.5 is added to the speed ratio (e) (+) because the predetermined value is set to -0.5, and the speed ratio (e) is smaller than -0.5. Only in this case is the wet multi-plate friction clutch 4 in the half-clutch state. That is, the speed ratio (e) obtained in step S1 is -0.5.
If it is smaller, the value of ((e + 0.5) × C) becomes minus (−) in the above equation for calculating the duty ratio (R), so that the duty ratio (R) is changed from the previous duty ratio (R) by ( The value calculated by (e + 0.5) × C) is minus (−). After determining the duty ratio (R) in this way, the control means 20 proceeds to step S4 and controls the electromagnetic switching valve 67 (V1) according to the duty ratio (R) determined in step S3.
Accordingly, the pressure in the hydraulic chamber 46 is reduced, and the wet multi-plate friction clutch 4 is brought into a half-clutch state. As a result, the transmission torque of the wet multi-plate friction clutch 4 decreases, so that the rotation speed of the clutch outer 41, that is, the turbine 33 driven from the transmission 5 via the clutch center 42 decreases, and the speed of the fluid coupling 3 decreases. The ratio (e) increases, and the torque transmission of the fluid coupling 3 is restored. For this reason, when the vehicle is retreating by gravity in a state where the transmission 5 is geared into the forward shift stage on a steep slope, the retreat of the vehicle can be prevented from increasing sharply. Further, when the vehicle is moved backward by gravity, when the accelerator pedal is depressed to shift to forward acceleration, the speed ratio (e) of the fluid coupling 3 further increases because the wet multi-plate friction clutch 4 is in the half-clutch state. The vehicle can be reliably advanced.

Next, when the speed ratio (e) is larger than -0.5 in the step S2, the control means 20 controls the so-called abrupt torque as in the case where the speed ratio (e) is -0.5 or less. It is determined that there is no risk of the disengagement occurring, and the process proceeds to step S5 to execute normal clutch control.

As described above, the present invention has been described based on the illustrated embodiments. However, the present invention is not limited to only the embodiments, and various modifications can be made within the technical idea of the present invention. For example, in the illustrated embodiment, an example is shown in which a wet multi-plate friction clutch is used as the friction clutch.
The present invention may be applied to a vehicle drive device using a dry single-plate friction clutch.

[0022]

The friction clutch control device for a vehicle drive device according to the present invention is constructed as described above, and has the following operational effects.

That is, according to the present invention, the speed ratio between the pump rotation speed of the fluid coupling and the turbine rotation speed is determined, and when the speed ratio is equal to or less than a predetermined value smaller than zero (0), the friction clutch is in the half-clutch state. When the vehicle is backing up due to gravity while the transmission is geared into the forward gear on a steep uphill slope, the vehicle retreats rapidly. It can be prevented from increasing. Also, when the vehicle is moved backward by gravity due to the depression of the accelerator pedal to shift to forward acceleration, the speed ratio (e) of the fluid coupling further increases because the wet multi-plate friction clutch is in the half-clutch state, so that it is ensured. The vehicle can move forward.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing an embodiment of a friction clutch control device for a vehicle drive device configured according to the present invention.

FIG. 2 is a flowchart showing an operation procedure of control means provided in the friction clutch control device of the vehicle drive device shown in FIG.

FIG. 3 is an explanatory diagram showing a state in which a vehicle equipped with a vehicle drive device equipped with a fluid coupling retreats on a steep ascending slope by gravity.

FIG. 4 is an explanatory diagram showing a relationship between a ratio (speed ratio) between a pump rotation speed and a turbine rotation speed of a fluid coupling and a transmission torque capacity coefficient.

[Explanation of symbols]

2: Internal combustion engine 21: Crankshaft 3: Fluid coupling 31: Fluid coupling casing 32: Fluid coupling pump 33: Fluid coupling turbine 34: Fluid coupling output shaft 4: Wet multi-plate friction clutch 41: Wet multi-plate friction Clutch outer 42: Clutch center of wet multi-plate friction clutch 43: Friction plate of wet multi-plate friction clutch 44: Annular cylinder of wet multi-plate friction clutch 45: Pressing piston of wet multi-plate friction clutch 46: Wet multi-plate Hydraulic chamber of friction clutch 47: Friction plate of wet multi-plate friction clutch 6: Hydraulic operation circuit 61: Reserve tank 62: Hydraulic pump 67: Electromagnetic switching valve (V1) 7: Engine rotation speed detection sensor (pump rotation speed detection means) 8: Clutch input element rotation speed detection sensor (turbine rotation speed detection means) 9: Clutch output element rotation speed Detecting sensor 10: accelerator pedal sensor (accelerator opening detection means) 20: Control unit

Claims (1)

[Claims] 1. A vehicle drive system comprising: an engine mounted on a vehicle; a fluid coupling operated by the engine; and a friction clutch disposed between the fluid coupling and a transmission. Pump rotational speed detecting means for detecting the rotational speed of the pump of the fluid coupling; turbine rotational speed detecting means for detecting the rotational speed and rotational direction of the turbine of the fluid coupling; clutch operating means for disconnecting and connecting the friction clutch And control means for controlling the clutch actuation means based on detection signals from the pump rotation speed detection sensor and the turbine rotation speed detection sensor. A speed ratio with respect to the rotation speed is obtained. Controls the switch actuating means, the friction clutch control device for a vehicular drive system, characterized in that.