JPS61247519A - Four-wheel drive vehicle - Google Patents

Abstract

PURPOSE:To prevent a tight corner braking phenomenon from occurring, by installing a detecting part which detects an inertial slow speed run from each output of a car speed switch, a neutral switch and a clutch switch and, at the time of detecting this inertial slow speed run, making a car perform a two-wheel drive run. CONSTITUTION:There are provided with a reverse switch 50 detecting a forward-backward motion by means of whether or not shifting to a reverse step, a 4WD switch 51 detecting operation on two-wheel drive or four-wheel drive, a neutral switch 52 detecting a neutral position, a clutch switch 53 detecting the extent of clutch pedal operation and a car speed switch 54 detecting a slow speed run, for example, of less than 5km/h. And, at an inertial slow speed run detecting part 55 inside a control circuit 46, the inertial slow speed run is detected from each output of these switches 52-54, and also a running mode is judged by a running model judging part 56 from each output of this detecting part 55 and each of these switches 50, 51 and 54, and at the time of detecting the inertial slow speed run, it is controlled so as to perform a two-wheel drive run.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a part-time four-wheel drive vehicle based on a direct connection between the front and rear wheels using a one-way clutch, and more particularly relates to a part-time four-wheel drive vehicle that is driven at slow speed due to inertia.

[Conventional technology]

Conventionally, for four-wheel drive vehicles using one-way clutches, one-way clutches for forward and reverse driving are provided in the middle of the transmission system of the front and rear wheels, as shown in Japanese Patent Laid-Open No. 60-15226, for example. 2. It is equipped with a four-wheel drive switching means and is configured as a part-time system. Then, forward or reverse is detected by the reverse switch, and 4WD is activated.
A switch detects 2WD or 4WD, and at least signals from these switches select a forward or reverse one-way clutch depending on each driving condition during four-wheel drive. Accordingly, it has been proposed that the vehicle travels in four-wheel drive while avoiding the tight corner braking phenomenon in both forward and reverse motions.

[Problems to be solved by the invention]

By the way, according to the control of the above-mentioned prior art, inertial slow running is not accurately controlled. That is, when the clutch pedal is depressed or the gear shift is in the neutral position, the vehicle may be traveling at a slow speed on a slope or the like due to inertia due to its own weight, and under such traveling conditions, the vehicle may be steered significantly. By the way, in this state, if the reverse switch and 4WD switch signals switch to four-wheel drive and the one-way clutch for forward or reverse is selected,
The one-way clutch may lock in a fully engaged state, causing a braking phenomenon. The present invention was created in view of the above points, and provides a four-wheel drive vehicle that can accurately judge inertial slow speed running and avoid braking phenomena under this running condition. The purpose is to

[Means for Solving the Problems 1] In order to achieve the above object, the present invention provides a detection system that detects a running condition in which the vehicle is in a neutral position or at a slow speed when the clutch pedal is depressed, using signals from a vehicle speed switch, a neutral switch, and a clutch switch. has a department. The vehicle also includes a determination unit that determines the forward or reverse driving modes of two-wheel drive and four-wheel drive based on signals from the detection unit, vehicle speed switch, 4WD switch, and gear shift switch. Even when four-wheel drive is operated, the vehicle is configured to switch to two-wheel drive when traveling at a slow speed due to inertia. [Function] Based on the above configuration, the present invention enables the vehicle to operate in two-wheel drive mode regardless of the 2.4-wheel drive switching operation, forward or reverse running state, and to operate the one-way clutch when traveling at a slow speed due to inertia. become unaffected. In this way, with the great invention, it is possible to reliably avoid the tight corner braking phenomenon that occurs when a large turn is made under the above-mentioned driving conditions.

【Example】

Hereinafter, one embodiment of the present invention will be specifically described based on the drawings. In FIG. 1, the transmission system and operation system of the four-wheel drive vehicle according to the present invention will be explained. It is a part-time type based on the two-wheel drive of RR, and there is an engine on the rear wheel side. A clutch 2 and a transmission 3 are arranged horizontally in the left-right direction of the vehicle body, and a rear differential device 4. A transfer device 5 and a one-way clutch device 16 are arranged in sequence, and a propeller shaft 1. Front differential device8. Front wheel 1 via axle 9
0 transmission configuration. And part of clutch 2. Shift 1113. Rear differential device 4. The transmission 1 device 5 is housed in a transmission case 11 to form a transaxle type, and a one-way clutch assembly M6 is housed in an extension case 13 that is connected to the transmission case 11 via an intermediate case 12. The transmission 3 is configured to have multiple sets of shift gears 17 and synchronizers 18 on the input shaft 15 and output shaft 16 from the clutch 2 to obtain multiple gear stages, and the rear differential device 4 is connected to the output shaft 16. The drive gear 19 is the final gear 20
A differential gear 21 is connected to a rear wheel 23 via an axle 22 and is attached to a final gear 20 . In the transfer device 5, a transfer gear 24 that meshes with the final gear 20 is integrally attached to a transformer 77 shaft 25 in the left-right direction of the vehicle body, and this transfer shaft 25 is connected to the front-rear direction of the vehicle body through a pair of bevel gears 26 and 27 for changing direction. The drive shaft 2B is connected to the drive shaft 2B. In the one-way clutch device 6, a forward one-way clutch 30 and a reverse one-way clutch 31 are installed in parallel on an inner race shaft 29 disposed coaxially with a drive shaft 28, and these drive shafts 28 and each one-way clutch 30 are installed in parallel. .31, an automatic switching device 32 is provided having three switching positions: neutral, forward and reverse. Here, when the outer race 30a rotates relatively faster than the inner race shaft 29, the forward one-way clutch 30 engages to directly connect the inner race shaft 29, giving forward rotation to the front wheel 10, and at the same time When the inner race shaft 29 rotates relatively quickly in this direction, the engagement is released and this is allowed. Further, the one-way clutch 31 for reverse operates in exactly the same way when the outer race 31a and the inner race shaft 29 rotate in the reverse rotation direction opposite to the above, and the inner race shaft 29 is faster in the same forward rotation direction as above. engage in case. The operation system of the automatic switching device 32 is as detailed in FIG.
Teeth 33a of the hub 33 integral with the drive shaft 28 and outer races 30a of both one-way clutches 30, 31. A sleeve 34 having teeth 34a, 34b on both ends of the inner circumference is fitted between the teeth 30b, 31b in the sleeve 31a so as to be movable in the axial direction, and one tooth 34a of the sleeve 34 is always engaged with the tooth 33a of the hub 33. Fit. On the other hand, the width of the other tooth 34b of the sleeve 34 is the same as the width of the teeth 30b, 31b of both outer races.
[134b is set between the teeth 30b and 31b of both outer races and is in a neutral position where it does not mesh with any of them, and from that position the tooth 30 is moved to the left side in FIG.
forward position where it engages with tooth b, and conversely move to the right side in Fig. 2 to engage tooth 3.
It has a reverse position where it engages with 1b. Note that reference numeral 41 is a lock ball means provided on the rod 37 for positioning the above three positions. On the other hand, the fork 38 of the rod 37 that is integral with the diaphragm 36 of the negative pressure actuator 35 is fitted into the sleeve 34, and the negative pressure chambers 39a on both sides of the diaphragm 36,
391), springs 40,41 are biased to keep the diaphragm 36 in a central position if both chambers leak to the atmosphere. Each negative pressure chamber 39a, 39b is connected to a Tesolenoid valve 43a, 43b via a passage 42a, 42b.
A negative pressure passage 44 to both solenoid valves 43a and 43b has a check valve 45 and the like and communicates with a negative pressure source such as the intake manifold of the engine 1. When the solenoid valves 43a and 43b are de-energized by a signal from the control circuit 46, the negative pressure passage side boat is closed and the actuator 3 is closed.
When the negative pressure chambers 39a and 39b of No. 5 are leaked to the atmosphere and reversely energized, the atmosphere side boat is closed and the negative pressure chambers 39a and 39b are
Introduce negative pressure to the In FIG. 3, the control system including the control circuit 46 will be explained. A reverse switch 50° 2WD or 4WD detects forward or reverse depending on the presence or absence of a shift to reverse gear.
4WD switch 51 that detects WD operation. Neutral switch 52 for detecting the neutral position. A clutch switch 531 that detects clutch pedal depression, for example, a vehicle speed switch 54 that detects running at a slow speed of less than ■/i.
has. and neutral switch 52. clutch switch 5
3 and the vehicle speed switch 54, the inertial slow running detection section 55 detects the inertial slow running.
5. Reverse switch 50.4WD switch 51. Based on the signal from the vehicle speed switch 54, a driving mode determining section 56 determines each driving mode. Here, when moving forward with four-wheel drive,
The detection unit 57 outputs an H level, and when moving backward, the detection unit 58 outputs an H level, and during two-wheel drive operation and inertial slow running, the outputs of both detection units 57 and 58 are set to an L level. do. Further, the output side of the detection unit 57 is connected to the base of a transistor 60, and the coil of a relay 61 is grounded via this transistor 60, and the contact side is connected to the solenoid valve 4.
Connect to 3a. The output side of the detection unit 58 is similarly connected to the base of a transistor 62, the coil of a relay 63 is grounded via this transistor 62, and the contact side of the relay 63 is connected to the solenoid valve 43b. Next, the operation of the four-wheel drive vehicle configured in this way will be explained in the fourth section.
This will be explained using the flowchart shown in the figure. First, when the 4WD switch 51 is turned off, the determination unit 5
6, the outputs of both detectors 57 and 58 become L level,
Relays 61.63 are also turned off together with transistors 60.62, and solenoid valves 43a and 43b are de-energized. Therefore, both angular pressure chambers 39a, 39b of the actuator 35 leak to the atmosphere due to the solenoid valves 43a, 43b, and since the diaphragm 36 is located in the center by the spring 40.41, @34b of the sleeve 34 is connected to the tooth 30b of the outer race. , 31b, which is a neutral position. For this reason, the one-way clutch device 6
, the inner race shaft 29 is separated from the drive shaft 28 and power is no longer transmitted to the front wheels, and the power from the transmission 3 is transmitted only to the rear wheels 23 via the rear differential device 4.
The R has two-wheel drive. On the other hand, when the 4WD switch 51 is turned on, if the vehicle speed is equal to or higher than the set vehicle speed and the vehicle speed switch 54 is turned off, and the reverse switch 50 is turned off and the vehicle is in the forward movement state, the determination section 56 determines that the output of the detection section 57 is set to H level. become. Therefore, the transistor 60 is turned on, the relay 60 energizes only the solenoid valve 43a, and negative pressure is introduced into one negative pressure chamber 39a of the actuator 35, thereby moving the sleeve 34 of the automatic switching device 132 from the neutral position. It moves to the left side in FIG. 2 and engages with the outer race 30a of the forward one-way clutch 30. In this way, the inner race shaft 29 is configured to transmit power to the drive shaft 28 via the forward one-way clutch 30, and when the drive shaft 28 rotates faster than the one-way clutch 30 when traveling straight ahead, the one-way clutch 30 is engaged. and becomes directly connected. Therefore, from the rear differential device 4 to the transfer device 5. One-way clutch equipment W16. Propeller shaft7. Power is also transmitted to the front wheels 10 via the front differential device 8 and the like, resulting in four-wheel drive. When the inner race shaft 29 rotates faster together with the front wheel 10 during a turn, the engagement of the one-way clutch 30 is released and the front wheel 10 rotates faster than the front wheel 10.
0 arbitrarily and turns smoothly without causing any braking phenomenon. When traveling backwards when the reverse switch 50 is turned on, the determination unit 5
6, the output of the detection section 58 becomes H level. Then, the transistor 62 is turned on and the solenoid valve 43b is energized by the relay 63, and the sleeve 34 is moved in the opposite direction to that described above due to the negative pressure in the other negative pressure chamber 39b of the actuator 35, and the outer race 31a of the one-way clutch 31 for reverse movement is moved. meshes with In this manner, when the drive shaft 28 rotates in the reverse direction, the one-way clutch 31 is engaged during straight running to provide four-wheel drive, and when turning, the one-way clutch 31 is disengaged and the vehicle turns without causing a braking phenomenon. In addition, when operating the four-wheel drive, if the vehicle speed switch 54 is turned on when the vehicle speed is lower than the set vehicle speed, and the clutch switch 53 is turned on by depressing the clutch pedal, or if the neutral switch 52 is turned on when it is in the neutral position, the detection unit 55, it is detected that the vehicle is running at slow speed due to inertia. Therefore, based on this detection result, the determination unit 56 determines that both detection units 5
By setting the output of 7.58 to L level, it becomes two-wheel drive as already mentioned. Therefore, even in the case of a large turning, it is possible to turn smoothly without causing a braking phenomenon. Note that when the clutch pedal is released during such low-speed running and the vehicle is driven by engine power while the vehicle is in a gear shift position other than neutral, the vehicle will drive forward or backward in four-wheel drive depending on the gear shift position as described above. Although the embodiments of the present invention have been described above, the automatic switching device 32 is in two positions, and the present invention can also be applied to a device having a transfer clutch for switching between 2 and 4 wheel drives. Also,
A part-time system based on FF is also applicable.

【Effect of the invention】

As described above, according to the present invention, the driving condition in which the vehicle runs at a slow speed due to inertia is detected, and in this case, the control is switched to two-wheel drive, so the brake is applied when a large turn is made under such conditions. This makes it possible to reliably avoid the rolling phenomenon and improve running performance.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram showing an embodiment of a four-wheel drive vehicle according to the present invention, Fig. 2 is a sectional view showing details of a one-way clutch device, Fig. 3 is a circuit diagram of the control system, and Fig. 4 is It is a flowchart figure explaining operation. 4... Rear differential device, 6... One-way clutch device, 8... Front differential device, 28... Drive shaft, 29... Inner race shaft, 30... One-way clutch for forward movement, 31...・One-way clutch for reverse,
32... automatic switching device, 34... sleeve, 35...
... Actuator, 43a, 43b... Solenoid valve, 4G... Control circuit, 50... Reverse switch, 51... 4WD switch, 52... Neutral switch, 53... Clutch switch, 54... ...Vehicle speed switch, 55...Inertial slow running detection section, 56.
...Driving mode determination section.

Claims (1)

[Scope of Claims] At least in the case of four-wheel drive, a one-way clutch for forward and reverse movement selected according to driving conditions, and means for switching between two and four-wheel drive are provided in the middle of the transmission system for the front and rear wheels. In a part-time four-wheel drive vehicle, there is an inertial slow running detection section that determines based on signals from the vehicle speed switch, neutral switch, and clutch switch, and signals from the vehicle speed switch, 4WD switch, gear shift switch, and inertial slow running detection section. A four-wheel drive vehicle, comprising: a driving mode determination unit that determines a two-wheel drive driving mode at least under inertial slow speed driving conditions.