JPS6324016Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

The present invention relates to a switching control device for a part-time four-wheel drive vehicle that normally drives two-wheel drive using either the front or rear wheels, but automatically switches to four-wheel drive by manual switch operation or depending on various driving conditions. In particular, it relates to a device that cancels the four-wheel drive when reversing when the four-wheel drive is automatically switched.

[Conventional technology and problems]

In general, 4-wheel drive vehicles are useful when you want to obtain a large amount of driving force, such as when starting off or climbing a hill, when slipping occurs easily on low-friction roads such as rain or snow, and when using engine braking during deceleration. It is known to exhibit good performance. Therefore, it has been proposed to equip a part-time type with a mechanism that detects each of the above-mentioned driving conditions and automatically switches, in addition to the manual switching mechanism. Regarding the above-mentioned automatic switching mechanism, there is conventional technology such as Japanese Utility Model Publication No. 48-8821 and Japanese Unexamined Patent Publication No. 56-43033, which automatically switches to four-wheel drive even in the first gear of the low gear or in the reverse gear. It is proposed that. However, in a part-time system in which a transfer clutch is used for the 2- and 4-wheel drive switching actuator and the front and rear wheels are directly connected by engaging the clutch during four-wheel drive, a difference in rotation occurs between the front and rear wheels when turning. It is known that tight corner braking occurs due to torsional torque in the drive system. Such a phenomenon is likely to occur under driving conditions in which the vehicle makes a sharp turn and backs up into a garage. Therefore, it is not preferable to automatically switch to four-wheel drive in reverse gear as in the prior art, as there is a high possibility that a braking phenomenon will occur. In view of the above-mentioned problems of the prior art, the present invention has been developed to cancel the 4-wheel drive when shifting to reverse gear when the 4-wheel drive is automatically switched depending on various driving conditions. An object of the present invention is to provide a switching control device for a four-wheel drive vehicle that makes it possible to avoid a tight corner braking phenomenon.

[Means to solve the problem]

For this purpose, the present invention directly transmits power to one of the front and rear wheels, operates the switching valve by energizing the solenoid, and engages the transfer clutch by supplying oil to the transfer clutch. In the four-wheel drive vehicle configured to transmit power to the other of the front and rear wheels, a manual changeover switch for two and four wheel drives is connected in series to the solenoid, and the four-wheel drive vehicle is provided with The normally open contacts of a relay that is linked to each of a plurality of detection switches that detect weather conditions and vehicle running conditions are connected in parallel to the manual changeover switch, and one end of the coil of the relay is connected to each of the plurality of detection switches. , and the other end thereof is connected to a back cancel circuit that operates in conjunction with a back switch that detects a shift to reverse gear via an automatic changeover switch for two- and four-wheel drive.

【Example】

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. First, referring to FIG. 1, an example of a transmission system of a four-wheel drive vehicle to which the present invention is applied will be described.
is a crankshaft from the engine, and this crankshaft 1 is connected to a turbine shaft 3 via a torque converter 2, and the turbine shaft 3 drives an automatic transmission 4.
The automatic transmission 4 is equipped with a planetary gear 5, clutches 6 and 7 for selectively inputting the power of the turbine shaft 3 to the input element of the gear 5, a one-way clutch 8 for selectively locking each element of the gear 5, a brake 9 and a brake band 10. The power changed from the automatic transmission 4 is taken out forward by an output shaft 11 and is reduced by reduction drive and driven gears 12 and 13 to the shaft 1.
The torque is transmitted to the rear wheels 6. A front wheel final reduction gear 14 is disposed below between the torque converter 2 and the automatic transmission 4, and a crown gear 15 of the front wheel final reduction gear 14 is engaged with a drive pinion 17 formed on one end of a shaft 16 integral with the gear 13, so that the vehicle runs in two-wheel drive mode using the front wheels. The other end of the shaft 16 is extended rearward by a transfer drive shaft 18, and is connected to transfer drive and driven gears 20, 21 of a transfer device 19 mounted on the rear part of the automatic transmission 4. The gear 21 is connected to a rear drive shaft 23 via a transfer clutch 22, which is a hydraulic clutch for switching between two-wheel and four-wheel drive, and the rear drive shaft 23 is further connected to a rear wheel final reduction gear 25 via a propeller shaft 24. Thus, when the clutch 22 is released by draining oil, the power transmission to the rear wheels is interrupted, and when it is engaged by oil supply, the power is further transmitted to the rear wheels, so that the vehicle runs in four-wheel drive mode. Next, the hydraulic control system of the clutch 22 will be described. An oil pump 26, which is a hydraulic source for the automatic transmission 4, is connected to the clutch 22 through an oil passage 28 having a switching valve 27.
7 has an inlet port 29 on the oil pump 26 side, an outlet port 30 on the clutch 22 side, and a drain port 31, and is configured to move a spool 34 depending on whether a solenoid 32 is energized and the action of a return spring 33. When the solenoid 32 is not energized, the inlet port 29 is closed and the outlet port 30 is closed as shown in the figure.
When the solenoid 32 is energized, the spool 3 is released.
4 moves to the left and closes the drain port 31,
The clutch 22 is supplied with oil and engaged by the communication between the inlet and outlet ports 30, 29, thereby switching between the two-wheel drive and four-wheel drive as described above. Referring to Fig. 2, the two-wheel drive and four-wheel drive switching control system is explained. From the power source side, the solenoid 32 of the switching valve 27 and the manual switching switch 40 are connected in series and grounded, and in the middle of this circuit, the coil 42a of the reed switch 42 in the checker unit 41 is connected in series. This reed switch 42
The contact 42b of the reed switch 42, the resistor 43 and the pilot lamp 44 are connected in parallel to the circuit. A tone indicator 45 for generating an electronic sound in the checker unit 41 is connected to the contact 42b of the reed switch 42 and the resistor 43.
The manual changeover switch 40 is connected to both sides of the windshield 40 and constitutes a display system using a lamp and an electronic sound when the changeover is performed. The automatic changeover system also includes a wiper switch 46 for detecting rain or snow, a tight-down switch 47 for detecting the tight-down operation, and a stop switch 48 for detecting the deceleration state. The manual changeover switch 40 is connected in parallel to a normally open contact 49b of a relay 49, and the coil 49 of the relay 49 is connected to the windshield 40.
One end of the coil 49 is connected to each of the switches 46, 47, and 48 via a diode 50, and the other end is connected to an automatic changeover switch 51.
Both ends of a are connected to an electronic sound cancel circuit 52 of the tone indicator 45 so that an electronic sound is not emitted when the automatic shift to four-wheel drive is performed. A back-cancel circuit 53 is further connected to the electric circuit having the automatic shift switch 5 and the like and is grounded. A back switch 54 for detecting a shift to the reverse gear is connected to the back-cancel circuit 53.
The operation of the device thus constructed will now be described. First, when the manual changeover switch 40 is turned off and the automatic changeover switch 51 is also turned off, the solenoid 32 of the changeover valve 27 is de-energized and the transfer clutch 22 is released by draining oil.
Reduction gears 12, 13 and shafts 16, 18
The power taken out from the reed switch 42 is transmitted only to the front wheels via the front wheel final reduction gear 14, thus providing two-wheel drive using only the front wheels.
Since the coil 42a is de-energized and the pilot lamp 44 is turned off, the tone indicator 45 is not lit either. On the other hand, when the manual changeover switch 40 is turned on, the solenoid 32 of the changeover valve 27 is energized and switched to supply oil to the transfer clutch 22, which causes the clutch 22 to engage. The power taken out from the automatic transmission 4 to the shafts 16, 18 is then transmitted to the rear wheels via the clutch 22, the rear wheel final reduction gear 25, etc., resulting in four-wheel drive running by the front and rear wheels. At this time, the coil 42a of the reed switch 42 is energized and switched to supply oil to the transfer clutch 22, which causes the clutch 22 to engage.
When the solenoid 32 is excited and turns on the contact 42b, the pilot lamp 44 is energized and lights up, indicating that the vehicle is in four-wheel drive. The tone indicator 45 detects the turning on of the contact 42b, and an electronic sound is generated from the tone indicator 45 for a certain period of time immediately after the vehicle switches to four-wheel drive, which also indicates the vehicle is in four-wheel drive. If the solenoid 32 circuit has a problem such as a broken wire and the vehicle does not actually switch to four-wheel drive, the reed switch 42 is also inoperative and the pilot lamp 44 and the tone indicator 45 are not activated.
Next, with the automatic changeover switch 5 turned on, switch 46 is turned on when the wipers are used during rain, switch 47 is turned on when the wipers are turned down, or switch 4 is turned on when the wipers are turned down.
When the switch 8 is turned on, the normally open contact 49b of the relay 49 is turned on by the excitation of the coil 49a. Then, the solenoid 32 is energized, and the vehicle is automatically switched to the four-wheel drive as described above, and the pilot lamp 44 is turned on. In this case, the potential across the coil 49a causes a cancel signal to be output from the circuit 52, and the tone indicator 45 does not emit an electronic sound. Also, in the state where the automatic switching is performed by the operation of the wiper switch 46, when the reverse switch 54 is turned on and the relay contact 55 of the reverse cancel circuit 53 is turned off when shifting to the reverse gear, the solenoid 32 is de-energized and the vehicle is in two-wheel drive. In this way, the four-wheel drive is released when reversing, and thus the tight corner braking phenomenon when making a sharp turn while reversing when parking in a garage, etc. is avoided. Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. Also,
It can also be applied to various part-time systems such as RR bases.

[Effect of the idea]

As is clear from the above explanation, according to the present invention, power is directly transmitted to one of the front and rear wheels, the switching valve is operated by energizing the solenoid, and the transfer clutch is operated by supplying oil to the transfer clutch. In a 4-wheel drive vehicle with a transmission configuration in which power is transmitted to the front and rear wheels by engaging the In addition, the normally open contacts of a relay that is linked to each of a plurality of detection switches that detect weather conditions and vehicle running conditions are connected in parallel to a manual changeover switch, and one end of the relay coil is connected to each of the plurality of detection switches.
The other end is connected to a back cancel circuit that is linked to a back switch that detects a shift to reverse gear via an automatic changeover switch for 2-wheel drive or 4-wheel drive. It is possible to switch between 2- and 4-wheel drive. Furthermore, by selecting an automatic transfer switch, it is possible to automatically switch between two and four wheel drive based on weather conditions and vehicle driving conditions. Furthermore, when the automatic changeover switch is selected and the vehicle is shifted from four-wheel drive to reverse gear, the vehicle is switched to two-wheel drive, thereby avoiding tight corner braking when making a sharp turn while reversing. Furthermore, since the switching valves for two-wheel drive and four-wheel drive are electrically controlled, the switching control system can be made compact.

[Brief explanation of the drawing]

FIG. 1 is a skeleton diagram showing an example of a four-wheel drive vehicle to which the present invention is applied, and FIG. 2 is a circuit diagram showing an embodiment of the device according to the present invention. 4... Automatic transmission, 14... Front wheel final reduction gear,
22...transfer clutch, 25...rear wheel final reduction gear, 27...2, 4-wheel drive switching valve, 3
2... Solenoid, 40... Manual changeover switch,
42...Reed switch, 46...Wiper switch, 47...Kick down switch, 48...
Stop switch, 49... Relay, 51... Automatic changeover switch, 53... Back cancel circuit, 54... Back switch.

Claims (1)

[Claims for Utility Model Registration] Power is directly transmitted to one of the front and rear wheels, the switching valve is operated by energizing the solenoid, and the transfer clutch is engaged by supplying oil to the transfer clutch. In a four-wheel drive vehicle configured to transmit power to the other of the front and rear wheels, a manual changeover switch for 2 and 4 wheel drive is connected in series to the solenoid, A normally open contact of a relay that is linked to each of the plurality of detection switches that detect the state and running state of the vehicle is connected in parallel to the manual changeover switch, and one end of the coil of the relay is connected to each of the plurality of detection switches, A switching control device for a four-wheel drive vehicle, characterized in that the other end is connected to a back cancel circuit linked to a back switch that detects a shift to reverse gear via an automatic changeover switch for two- and four-wheel drive.