JP2004019769A - Electronically controlled coupling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the durability by using a hydraulically operated wet type multiple disk clutch inside a complete mechanism, and at the same time, to enhance the degree of freedom of installation with a compact and simple constitution. <P>SOLUTION: An oil pump 4 to be driven by an electric motor 5 is continuously connected to a coupling case 3 to reservoir oil inside by storing the wet type multiple disk clutch 2. And, a discharging port of the oil pump 4 is directly connected to an oil pressure chamber 2a of the wet type multiple disk clutch 2 via a hydraulic supply passage 8, and at the same time, a throttle 10 is interposed by branching a cooling oil passage 9 from the middle of the hydraulic supply passage 8. The body of the wet type multiple disk clutch 2 is forcibly cooled by the oil from the cooling oil passage 9 while executing the control to make pump discharge pressure to become request operation pressure of the wet type multiple disk clutch 2 by controlling the number of rotation of the electric motor 5 via a motor driver 6 from an ECU 7. By this, even in the case of having no hydraulic source, the durability as the coupling is enhanced by using the hydraulically operated wet type multiple disk clutch inside the complete mechanism, and at the same time, the degree of the freedom of the installation is enhanced with the compact and simple constitution. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electronically controlled coupling that transmits torque via a multi-plate clutch that is operated by hydraulic pressure.
[0002]
[Prior art]
Conventionally, in a power transmission system of a four-wheel drive vehicle, a coupling mechanism such as a multi-plate clutch or a viscous coupling is provided, and the drive force is continuously distributed to the rear wheels through the coupling mechanism. In particular, in a four-wheel drive vehicle equipped with an automatic transmission, a hydraulically operated wet multi-plate clutch is often employed because a hydraulic pressure source of the automatic transmission can be used.
[0003]
On the other hand, when the vehicle does not have its own hydraulic pressure source, such as a vehicle with a manual transmission, a coupling that couples the multi-plate clutch with a mechanical driving force may be used. Such a coupling is disclosed, for example, in Japanese Patent Application Laid-Open No. 2000-346102. In this coupling, a control clutch, which is a metal multi-plate clutch, is pressed and fastened by an armature of an electromagnet, and the control clutch is fastened. The torque is transmitted to the main clutch, which is a wet-type multi-plate clutch, via the cam mechanism, and is engaged.
[0004]
[Problems to be solved by the invention]
However, the coupling disclosed in the above-mentioned prior art operates the control clutch by an electric signal and amplifies the pressing load of the wet multi-plate clutch by using a mechanical cam mechanism. There are difficulties in durability, wear resistance, and controllability of the clutch due to a change in coil temperature.
[0005]
In the case of employing a hydraulically operated wet multi-plate clutch, the above-mentioned problems can be reduced by lubrication and cooling with oil. A hydraulic circuit and various pressure regulating valves for obtaining the operating pressure are required, which imposes restrictions on outfitting.
[0006]
The present invention has been made in view of the above circumstances, and enhances the durability as a coupling by using a hydraulically operated wet multiple disc clutch in a completed coupling mechanism, and has a compact and simple configuration that allows freedom in outfitting. It is an object of the present invention to provide an electronically controlled coupling capable of increasing the degree.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is an electronically controlled coupling for transmitting torque via a wet type multi-plate clutch which is coupled and operated by hydraulic pressure, wherein the multi-plate clutch is housed in a case storing the multi-plate clutch. Along with storing oil to be supplied to a hydraulic chamber for performing a joint operation, an oil pump driven by an electric motor is connected to the case, and a discharge pressure of the oil pump directly acts on the hydraulic chamber. The discharge port of the oil pump is directly connected to the hydraulic chamber through a closed-circuit hydraulic supply path that is a dead end in the hydraulic chamber, and further includes a cooling oil passage for supplying oil for cooling the multi-plate clutch. Control for controlling the number of revolutions of the electric motor so that the oil pressure is branched from the hydraulic pressure supply path and the discharge pressure of the oil pump becomes the required operating pressure of the multi-plate clutch. Characterized by comprising a stage.
[0008]
That is, in the present invention, an oil pump driven by an electric motor is connected to a case that stores and stores oil by storing a wet multi-plate clutch, and the discharge pressure of the oil pump directly acts on a hydraulic chamber of the multi-plate clutch. The discharge port of the oil pump is directly connected to the hydraulic chamber through a closed circuit hydraulic supply path that is dead-ended in the hydraulic chamber, and a cooling oil passage that supplies oil for cooling the multi-plate clutch from the hydraulic supply path. By branching and controlling the number of revolutions of the electric motor so that the discharge pressure of the oil pump becomes the required operating pressure of the multi-plate clutch, even if it does not have a hydraulic source, the hydraulic operation is completed within a complete mechanism. The durability as a coupling is increased by using a multi-plate clutch, and the degree of freedom in outfitting is increased with a compact and simple configuration. At this time, it is desirable to provide a throttle in the cooling oil passage and limit the flow rate of the cooling oil to a necessary minimum.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 4 relate to an embodiment of the present invention, FIG. 1 is a basic configuration diagram of an electronic control coupling, FIG. 2 is a sectional view of a main portion around a transfer of a transmission, and FIG. FIG. 4 is a flowchart showing a control process of an electronic control unit (ECU).
[0010]
In FIG. 1, reference numeral 1 denotes an electronic control coupling 1 interposed in a power transmission system of a vehicle, and the drive torque is transmitted by alternately stacking a plurality of drive and driven plates so as to make surface contact with each other. A wet multi-plate clutch 2; a coupling case 3 in which the wet multi-plate clutch 2 is housed and oil is stored therein; Pump 4 that supplies oil directly to the motor, an electric motor (hereinafter simply referred to as a motor) 5 that drives the oil pump 4, a motor driver 6 that drives the motor 5, and an electronic control unit (ECU) 7 that controls the motor driver 6. And are integrally configured. The oil in the coupling case 3 is sealed in the coupling case 3 for operating hydraulic pressure and lubrication of the wet multi-plate clutch 2.
[0011]
The discharge port of the oil pump 4 is directly connected to a hydraulic chamber 2 a for connecting and operating the wet multi-plate clutch 2 via a hydraulic supply path 8. The oil in the ring case 3 is sucked and pressurized, and the discharge pressure of the oil pump 4 directly acts on the hydraulic chamber 2 a of the wet multi-plate clutch 2.
[0012]
That is, the hydraulic supply path 8 that guides the oil discharged from the oil pump 4 to the wet-type multi-plate clutch 2 is a path that forms a dead-end closed circuit having no return path from the hydraulic chamber 2a, and is controlled by the rotation speed of the motor 5. The coupling operation of the wet multi-plate clutch 2 is controlled only by adjusting the pump discharge pressure, and a pilot circuit and a return circuit for pressure adjustment, and various adjustment valves such as a pressure adjustment valve and a relief valve are unnecessary.
[0013]
The rotation speed control of the motor 5 is executed by the ECU 7 via the motor driver 6. The ECU 7 determines an operation state based on signals from various sensors (not shown) such as a wheel speed sensor and an acceleration sensor, and determines a transmission torque corresponding to the operation state. Then, the rotation speed of the motor 5 is controlled so that the discharge pressure of the oil pump 4 becomes the required operating pressure of the wet multi-plate clutch 2 that generates this transmission torque.
[0014]
Specifically, when the wet-type multi-plate clutch 2 is in the clutch disengaged state, the motor 5 is controlled to a standby state at a predetermined number of revolutions in order to secure the startup response. The number of revolutions in the standby state is a number of revolutions for maintaining the discharge pressure of the oil pump 4 lower than the operating pressure for engaging the clutch. When the clutch is operated in the engaging direction, the number of revolutions of the motor 5 increases. Then, the number of rotations is controlled to a pump discharge pressure for generating a necessary transmission torque.
[0015]
In this case, since the discharge oil from the oil pump 4 reaches a dead end in the hydraulic chamber 2a of the wet multi-plate clutch 2, a relatively large load is expected to be applied to the oil pump 4 and the motor 5. For this reason, when, for example, a gear pump is adopted as the oil pump 4, the pump load is reduced by setting the side clearance relatively large in advance. Further, as the motor 5, it is desirable to employ a brushless motor in order to increase durability, and furthermore, by introducing a motor that can be used in oil, the degree of freedom in outfitting can be increased. It can be compact.
[0016]
Further, in order to effectively cool the wet multi-plate clutch 2, a cooling oil passage 9 is branched from the middle of the hydraulic supply passage 8, and the oil from the cooling oil passage 9 forcibly forces the wet multi-plate clutch 2 body. Cool down. In order to reduce the flow rate of the oil for forced cooling to a minimum necessary flow rate, the flow rate is limited by interposing a throttle 10 in the cooling oil passage 9. The throttle 10 is not always necessary. In short, it is only necessary to secure the minimum flow rate required for cooling without affecting the clutch operation, and the throttle 10 may be omitted.
[0017]
FIG. 2 shows an example in which the above-described electronically controlled coupling 1 is applied to a four-wheel drive vehicle equipped with a manual transmission. The electronically controlled coupling 1 is continuously provided as a transfer behind a transmission (manual transmission) 20.
[0018]
The transmission 20 is configured such that the transmission 20 idles on a main shaft 21 connected to an output shaft of an engine via a clutch (not shown) in accordance with a gear change operation, and shifts on a drive pinion 22 which always meshes with the transmission gear. The gears are respectively engaged by the synchromesh mechanism 23.
[0019]
The driving force of the engine transmitted to the main shaft 21 is transmitted from a front differential (not shown) to a front wheel via a drive pinion 22 and via a transfer drive gear 24 coupled to a rear shaft end of the drive pinion 22. The power is transmitted to the transfer driven gear 25. The transfer driven gear 25 is connected to a clutch shaft 26 serving as an input shaft of the electronic control coupling 1, and a rear wheel output shaft 27 serving as an output shaft of the electronic control coupling 1 is not shown via a propeller shaft 28. The driving force is distributed to the rear wheels and is connected to the rear differential device.
[0020]
Hydraulic oil and lubricating oil for the wet multi-plate clutch 2 are stored in the coupling case 3 configured as a transfer case. The wet multi-plate clutch 2 in the case is expanded in diameter from the clutch shaft 26. A clutch drum 31, a clutch hub 31 coupled to the outer periphery of the rear wheel output shaft 27, a clutch plate portion 32 that continuously connects and disconnects the clutch drum 30 and the clutch hub 31, and a clutch plate portion. And a piston 34 for pressing the pressing member 32 through the pressing member 33. On the rear side of the piston 34, a hydraulic chamber 2a for coupling the clutch is formed by transmitting the pressing force to the pressing member 33 by moving the piston 34 in the axial direction.
[0021]
A bearing 35 is provided between the pressing member 33 and the piston 34 so that the pressing force can be transmitted to the rotating pressing member 33 by the linear movement of the piston 34. Reference numeral 36 denotes a return spring that urges the clutch plate 32 in the opening direction with respect to the pressing force of the piston 34.
[0022]
A pump unit in which the oil pump 4 and the motor 5 are integrated is connected to a side wall 3a formed below the output shaft 27 for the rear wheel of the coupling case 3, and the inside of the side wall 3a An oil suction passage 37 communicating with a suction port of the oil pump 4 and opening into the coupling case 3; a hydraulic supply path 8 directly connecting the discharge port of the oil pump 4 to the hydraulic chamber 2a of the wet multi-plate clutch 2; A cooling oil passage 9 is provided which branches off from the hydraulic pressure supply path 8, passes through the throttle 10, and opens in a space around the output shaft 27 for the rear wheel of the coupling case 3.
[0023]
The transmission 20 and the electronic control coupling 1 as a transfer are separated from each other via an oil seal 38 mounted on the outer periphery of the clutch shaft 26, and the oil inside the transmission 20 and the electronic control coupling 1 are separated from each other. 1 is separated from the oil. In this case, the same oil may be used in the transmission 20 and the electronic control coupling 1, or the oil in the electronic control coupling 1 may be different from the oil in the transmission 20, and Oil considering the characteristics of the plate clutch 2 and the oil pump 4 may be used.
[0024]
In the electronic control coupling 1 as such a transfer, the rotation speed of the motor 5 is controlled by the ECU 7 so as to generate a transmission torque determined according to the running state of the vehicle, the road surface state, and the like, and the torque distribution between the front and rear wheels is performed. Is variably controlled between 100: 0 (clutch disengagement) and 50:50 (clutch engagement).
[0025]
In the variable control of the transmission torque by controlling the rotation speed of the motor 5, the clutch operating pressure is obtained since the discharge oil of the oil pump 4 is directly sent to the hydraulic chamber 2a of the wet multi-plate clutch 2 as the clutch operating pressure. Controllability can be improved without being affected by various hydraulic circuits, pressure regulating valves, and the like. Further, since the wet multi-plate clutch 2 is forcibly cooled through the cooling oil passage 9, the durability of the clutch can be improved.
[0026]
On the other hand, FIG. 3 shows an example in which the electronic control coupling 1 is provided between a propeller shaft and a rear differential device. In the figure, the coupling case 3 of the electronic control coupling 1 extends rearward and also serves as a part of the case of the rear differential device 40, and a clutch shaft 26 serving as an input shaft of the electronic control coupling 1. Is connected to the rear end of the propeller shaft, and a rear wheel output shaft 27 serving as an output shaft of the electronic control coupling 1 is connected via a bevel gear 41 to a rear differential device 40 containing a viscous coupling 42. . The internal configuration of the electronic control coupling 1 is basically the same as that of the above-described transfer, except that the configuration around the output shaft is slightly different and the opening position of the cooling oil passage 9 is slightly different.
[0027]
Next, a program process of the ECU 7 for controlling the electronic control coupling 1 will be described with reference to a flowchart shown in FIG. 4 as an example.
[0028]
In this process, first, in a step S101, it is determined whether or not an ignition switch (not shown) is turned on. This step is a step for setting the electronic control coupling 1 in a standby state before driving the vehicle. In addition to the ignition switch, for example, a signal from a switch that is turned on when a vehicle door is opened is used. The determination may be made.
[0029]
In step S101, when the switch is OFF, the command torque of the motor 5 is set to 0 in step S102 to deactivate the electronic control coupling 1 (clutch disengagement). 5 is operated in standby at a preset number of revolutions.
[0030]
In the following step S104, it is determined whether or not the front and rear wheels are slipping based on the signals from the front and rear wheel speed sensors. As a result, if no slip has occurred, it is determined in step S105 whether or not the vehicle has started, and if it has been started, control in starting is performed in step S106. In this starting control, for example, the command torque of the motor 5 is set in accordance with the throttle opening of the engine, and in the case of a gentle start, the discharge pressure of the oil pump 4 is increased relatively slowly to increase the clutch engagement pressure. When a rapid start is required, the discharge pressure of the oil pump 4 is rapidly increased so that the clutch is quickly engaged.
[0031]
In step S105, if the vehicle is not starting, the process proceeds from step S105 to step S107, and it is determined whether the control is the normal control. If NO, the process returns to step S103, and if YES, the process proceeds to step S108 to perform normal control. In this normal control, for example, the command torque of the motor 5 is determined based on the throttle opening and the vehicle speed, and the discharge pressure of the oil pump 4 is controlled so as to be a clutch operating pressure that generates a transmission torque corresponding to the driving state. .
[0032]
On the other hand, if it is determined in step S104 that slippage has occurred in the front and rear wheels, the process proceeds from step S104 to step S109 to perform slip control. In the slip control, for example, when the front wheel slips, the instruction pressure of the motor 5 is increased according to the degree of the slip to adjust the discharge pressure of the oil pump 4, that is, the clutch engagement pressure, and the slip of the front wheel is suppressed.
[0033]
As described above, in the present embodiment, the wet multi-plate clutch 2, the oil pump 4, and the motor 5 are integrated, and the oil pump 4 is driven by controlling the rotation speed of the motor 5 to control the clutch engagement pressure. As a coupling that is compact and mechanically complete, the degree of freedom in outfitting can be increased, and the coupling can be easily applied to a power transmission system of a vehicle. This is particularly effective for vehicles equipped with a manual transmission that does not have its own hydraulic power source.
[0034]
In addition, since the multi-plate clutch is forcibly cooled by oil, not only the thermal durability of the clutch can be improved, but also the clutch operating pressure can be controlled by controlling the rotation speed of the motor 5, so that the clutch operating pressure can be controlled. This eliminates the need for a hydraulic circuit and various pressure regulating valves for obtaining the operation, thereby reducing costs.
[0035]
【The invention's effect】
As described above, according to the present invention, the durability as a coupling can be increased by using a hydraulically operated wet multi-plate clutch in a completed mechanism, and the degree of freedom in outfitting is reduced by a compact and simple configuration. Can be increased.
[Brief description of the drawings]
FIG. 1 is a basic configuration diagram of an electronic control coupling. FIG. 2 is a cross-sectional view of a main portion around a transfer of a transmission. FIG. 3 is a cross-sectional view of a main portion around a rear differential device. FIG. 4 is a flowchart showing a control process of an ECU. [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Electronic control coupling 2 Wet type multi-plate clutch 2a Hydraulic chamber 3 Coupling case 4 Oil pump 5 Electric motor 6 Motor driver 7 Electronic control unit 8 Hydraulic supply path 9 Cooling oil path 10 Throttle

Claims (2)

An electronically controlled coupling that transmits torque via a wet multi-plate clutch that operates by hydraulic pressure,
In a case for storing the multi-plate clutch, oil to be supplied to a hydraulic chamber for coupling and operating the multi-plate clutch is stored, and an oil pump driven by an electric motor is connected to the case,
The discharge port of the oil pump is directly connected to the hydraulic chamber through a closed-circuit hydraulic supply path that is a dead end in the hydraulic chamber so that the discharge pressure of the oil pump directly acts on the hydraulic chamber. A cooling oil passage for supplying oil for cooling the plate clutch is branched from the hydraulic supply passage,
An electronic control coupling, comprising: control means for controlling the number of revolutions of the electric motor so that a discharge pressure of the oil pump becomes a required operating pressure of the multi-plate clutch. 2. The electronically controlled coupling according to claim 1, wherein a throttle is interposed in the cooling oil passage.

Images