JP2555821Y2 - Two-wheel drive-four-wheel drive switching device - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to a transfer device 2
The present invention relates to a four-wheel drive switching device.

[0002]

2. Description of the Related Art As a hydraulic circuit for switching between two-wheel drive and four-wheel drive in a conventional transfer device, for example, there is a hydraulic circuit as shown in FIG. First, in FIG.
Denotes a main shaft of the transfer device, and a first oil pump 52 is provided on the main shaft 51. 53 is a DC motor externally attached to the transfer device, and DC motor 53 is a second oil pump 54 attached separately.
Drive. Oil is sucked into the first oil pump 52 and the second oil pump 54 from an oil sump 55 via an oil strainer 56, and the first oil pump 52 and the second oil pump 54 operate to allow one-way oil passages 57 and 58. Each discharge pressure is supplied to the regulator valve 61 and the shift valve 62 via the valves 59 and 60. A regulator valve 61 adjusts each discharge pressure to a line pressure, and a shift valve 62 switches the line pressure.

A solenoid valve 63 controls the drive of the shift valve 62. When the solenoid valve 63 is off, the shift valve 62 is operated, and the line pressure is supplied to the wet multi-plate clutch mechanism 64 to be in the 4WD position. . On the other hand, when the solenoid valve 63 is turned on, the shift valve 62 is deactivated, and the line pressure is not supplied to the wet multi-plate clutch mechanism 64, and the position becomes 2WD.
In order to secure a hydraulic pressure at which the wet multi-plate clutch mechanism 64 is turned on, the pressure of the regulator valve 61 is set in accordance with the on-pressure of the wet multi-plate clutch mechanism 64.
In addition, 65 is an orifice and 66 is a relief valve.

[0004]

However, in such a conventional 2WD-4WD switching device, when the wet multi-plate clutch mechanism is off, the hydraulic pressure is drained by the regulator valve, but the hydraulic pressure is set by the regulator. Due to the pressure, there is a problem that the torque loss by the oil pump is large. Torque cross = (ΔP · VP) / (2π · η) (ΔP is a line pressure, VP is a discharge pressure, and η is a pump efficiency.) The present invention has been made in view of such a conventional problem. It is an object of the present invention to provide a 2WD-4WD switching device capable of reducing the torque loss of an oil pump.

[0005]

In order to achieve the above object, the present invention provides a wet multi-plate clutch mechanism using a first oil pump provided on a main shaft or a second oil pump separately driven by a DC motor. A hydraulic circuit, comprising: a regulator valve for regulating the discharge pressures of the first and second oil pumps, a shift valve for switching the regulated line pressure, and a solenoid valve for driving and controlling the shift valve. Further, a setting means is provided for setting the line pressure to zero by forcibly pressing the regulator valve during two-wheel drive.

[0006]

When the vehicle travels in 2WD, the setting valve forcibly presses the regulator valve to fully open the regulator valve and set the line pressure to zero. Therefore,
The torque loss of the oil pump can be reduced. 4
During traveling of the WD, the regulator valve does not forcibly press the regulator valve, so the regulator valve regulates the hydraulic pressure by setting the spring load.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are views showing an embodiment of the present invention. First, the transfer device will be described. In FIG. 2, reference numerals 1 to 3 denote casings.
3, a main drive shaft 4 to which the driving force from the engine is transmitted, and a main shaft 5 extending toward the propeller shaft are rotatably supported by bearings.

A main drive gear 7 meshing with a counter gear 6 is formed integrally with the main drive shaft 4, and the counter gear 6 is further provided with a low-speed gear rotatably mounted on the main shaft 5 via a needle bearing. 8, the rotational force of the main drive shaft 4 is transmitted to the low speed gear 8 via the main drive gear 7 and the counter gear 6. Reference numeral 9 denotes a hub fitted to the main shaft 5 with splines, and the coupling sleeve 1
0 is slidably meshed.

As shown, the coupling sleeve 10
Is in the neutral position, the main shaft 5 does not rotate because the rotational force of the main drive shaft 4 is not transmitted. On the other hand, when the coupling sleeve 10 is moved to mesh with the clutch gear 7 a of the main drive gear 7, the rotational force of the main drive gear 7 is transmitted to the main shaft 5 via the coupling sleeve 10 and the hub 9.
And the main shaft 5 rotates at high speed.

On the other hand, when the coupling sleeve 10 is moved to mesh with the clutch gear 8a of the low speed gear 8, the rotational force of the main drive gear 7 causes the counter gear 6, the low speed gear 8, the coupling sleeve 10 and the hub 9 to rotate. The main shaft 5 is transmitted to the main shaft 5 at a low speed with a reduction ratio set by the counter gear 6.

Reference numeral 11 denotes a wet multi-plate clutch mechanism for performing two-wheel drive / four-wheel drive switching and torque variable control. The wet multi-plate clutch mechanism 11 includes a drum 12 spline-coupled to the main shaft 5, A plate 13 spline-coupled to the inner periphery, a drive sprocket 14
, A plate 16 splined to the hub 15, and these plates 13, 16
And a piston 17 for pressing the pressure.

A chain 19 is provided between the drive sprocket 14 and the driven sprocket 18, and the driven sprocket 18 is connected to a front drive shaft 20.
Are integrally formed. Front drive shaft 20
Is rotatably supported by casings 1 and 2 via bearings 21 and 22. Reference numeral 23 denotes a first oil pump provided on the main shaft 5, and the first oil pump 23 is driven by the main shaft 5. The first oil pump 23 supplies a piston working pressure to a piston liquid chamber 24 and supplies lubricating oil to an oil passage 25.

A second oil pump 26 is separately attached to the casing 2, and the second oil pump 26 is driven by a DC motor 27. As shown in the hydraulic circuit of FIG. 1, the discharge pressures of the first oil pump 23 and the second oil pump 26 are supplied from oil passages 28, 29 to one-way valves 30,
It is supplied to a regulator valve 32 and a shift valve 33 via 31. The regulator valve 32 adjusts each discharge pressure to a line pressure, and the shift valve 33 switches the line pressure.

Reference numeral 34 denotes a solenoid valve controlled by a control unit (not shown). When the solenoid valve 34 is off, the shift valve 33 is operated to send the line pressure to the wet-type multi-plate clutch mechanism 11, and when the solenoid valve 34 is on, the shift valve is shifted. The valve 33 is deactivated to prevent the line pressure from being sent to the wet multi-plate clutch mechanism 11. When the line pressure is supplied, the wet multi-plate clutch mechanism 11 is turned on, thereby obtaining a position of 4WD. When the line pressure is not supplied, the wet multi-plate clutch mechanism 11 is turned off.
Position is obtained.

Reference numeral 35 denotes a solenoid valve as setting means. When the solenoid valve 35 is off, the solenoid valve 35 does not press the regulator valve 32. Therefore, at this time, the pressure of the regulator valve 32 is adjusted by setting the spring load. When the solenoid valve 35 is on, the regulator valve 32 is forcibly pressed, is fully opened (open), and the hydraulic pressure is zero. In addition, 36 is a relief valve, and 42 is an orifice.

Next, the operation will be described. During 4WD traveling, the solenoid valve 35 is turned off and the regulator valve 32 is not pressed. Therefore, the regulator valve 32 adjusts the pressure by the spring load, and the adjusted line pressure is supplied to the shift valve 33. At this time,
The solenoid valve 34 is controlled to be turned off, the shift valve 33 is operated, the oil passage 37 is closed, the oil passage 38 is opened, and the regulated line pressure is supplied to the wet multi-plate clutch mechanism 11.

At the time of 2WD running, the solenoid valve 3
5 is turned on, and the regulator valve 32 is forcibly pressed. Therefore, the regulator valve 32 moves downward in the drawing against the spring 39, and the oil passage 40 is fully opened. For this reason, the line pressure becomes zero, and the torque cross by the oil pumps 23 and 26 can be reduced.

At this time, the solenoid valve 34 is controlled to be on, drains the hydraulic pressure, the shift valve 33 opens the oil passage 37, closes the oil passage 38, and the line pressure is not supplied to the wet multi-plate clutch mechanism 11. Next, FIG. 3 shows another embodiment of the present invention. In FIG. 3, reference numeral 41 denotes a solenoid valve as a setting means.
In the case of WD, it is controlled to be ON and the regulator valve 32
Adjusts the pressure by setting the spring load.

At the time of 2WD, the solenoid valve 41 is controlled to be turned off, the regulator valve 32 is fully opened,
Set the line pressure to zero. Also in this embodiment, the torque loss of the oil pumps 23 and 26 can be reduced as in the above-described embodiment.

[0020]

As described above, according to the present invention, when the vehicle is running at 2WD, the regulator valve is fully opened and the line pressure is reduced to zero, so that the torque loss of the oil pump can be reduced.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a transfer device.

FIG. 3 is a diagram showing another embodiment of the present invention.

FIG. 4 is a conventional hydraulic circuit diagram.

[Explanation of symbols]

 1-3: Casing 4: Main drive shaft 5: Main shaft 6: Counter gear 7: Main drive gear 7a: Clutch gear 8: Low speed gear 8a: Clutch gear 9: Hub 10: Coupling sleeve 11: Wet multi-plate clutch mechanism 12: Drum 13, 16: Plate 14: Drive sprocket 15: Hub 17: Piston 18: Driven sprocket 19: Chain 20: Front drive shaft 21, 22: Bearing 23: First oil pump 24: Piston liquid chamber 25: Oil passage 26: second oil pump 27: DC motor 28, 29: oil path 30, 31: one-way valve 32: regulator valve 33: shift valve 34: solenoid valve 35, 41: solenoid valve (setting means) 36: relief valve 7,38,40: oil path 39: Spring 42: Orifice

Claims (1)

(57) [Scope of request for utility model registration] 1. A transfer device for driving a wet multi-plate clutch mechanism by a first oil pump provided on a main shaft or a separately attached second oil pump driven by a DC motor. A hydraulic circuit equipped with a regulator valve that regulates each discharge pressure and a shift valve that switches the regulated line pressure, and a hydraulic circuit that includes a solenoid valve that drives and controls the shift valve, forcibly presses the regulator valve when driving two wheels. A two-wheel drive / four-wheel drive switching device, further comprising setting means for setting the line pressure to zero.