JPS6340687B2 - - Google Patents

Description

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

The present invention relates to a part-time four-wheel drive vehicle that does not have a center differential but has a transfer device for switching between two and four-wheel drives to switch to four-wheel drive as necessary, and particularly relates to This relates to a one-way clutch provided in the middle of the transmission system to one of the wheels.

[Prior art and problems]

As a four-wheel drive vehicle without a center differential, a vehicle in which the transmission systems of the front and rear wheels are directly connected by a clutch has been proposed, for example, as shown in Japanese Patent Application Laid-open No. 55-4292. However, with this front and rear wheel direct connection type, 4
When turning with wheel drive, if there is a difference in the turning radius of the front and rear wheels, a so-called tight corner braking phenomenon occurs. Therefore, in order to avoid such a braking phenomenon, an automatic switching device to two-wheel drive based on the steering angle is required, as shown in Japanese Patent Application Laid-Open No. 57-15019, which makes the structure complicated and further improves the road surface. When the occurrence of a braking phenomenon changes depending on the state, etc., there is a problem that it is difficult to avoid it accurately.

[Purpose of the invention]

In view of these circumstances, the present invention is a part-time system having a transfer device for switching between two-wheel drive and four-wheel drive. To provide a four-wheel drive vehicle that automatically avoids braking phenomena.

[Structure of the invention]

In order to achieve this object, the present invention provides a transfer device and two types of one-way clutches for forward and reverse in the transmission system of the front and rear wheels.
It is equipped with means for detecting a backward drive state, and a switching means for selectively transmitting and connecting the two types of one-way clutches in response to signals indicating a forward or reverse four-wheel drive state from both of these detecting means. The two types of one-way clutches mentioned above are selectively connected for transmission when moving forward or backward with four-wheel drive, and the one-way clutch is integrated to directly transmit power to the front and rear wheels, thereby controlling the rotation of the front and rear wheels when turning. The purpose of the braking phenomenon caused by the difference is to release the one-way clutch and avoid absorption. The four-wheel drive vehicle disclosed in Japanese Patent Publication No. 32-2321 is designed so that the front wheels rotate faster than the rear wheels when turning, but it has a center differential, and if the front wheels slip, the center differential is activated. This is different from the present invention in that it locks and prevents the front wheels from further slipping, thereby preventing the risk of stalling of the vehicle.

【Example】

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. Referring to FIG. 1, the transmission 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 reference numeral 1 denotes a drive system having an engine, a clutch, and a transmission. , which is directly transmitted to the rear wheels 4 via the rear wheel differential device 2 and the rear wheel axle 3. Further, the rear wheel differential device 2 is a transfer device 5.
2, is connected to two sets of one-way clutches 8 and 9 via a four-wheel switching transfer clutch 6 and a direction conversion gear 7, and is further connected to a front wheel 13 via a propeller shaft 10, a front wheel differential device 11, and a front wheel axle 12. Transmission is configured. In FIG. 2, the one-way clutches 8 and 9 will be described in detail. The gear shaft 14 and the drive shaft 15 to the propeller shaft 10 are arranged coaxially,
A connecting drum 16 is integrally coupled to the gear shaft 14,
A reverse one-way clutch 8 and a forward one-way clutch 9 are arranged adjacent to each other on the outer periphery of the drive shaft 15.
A slide sleeve 17 is mounted between the one-way clutches 8, 9 and the connecting drum 16 around their outer peripheries. This sleeve 17 has spline internal teeth 17a and 17b at the front and rear, and moves in the axial direction with the rear spline internal teeth 17b always meshing with the external teeth 16a of the connecting drum 16, and the front spline internal teeth 17a. is adapted to be selectively fitted into one of the outer race side external teeth 8a, 9a of the one-way clutches 8, 9. Here, when the forward one-way clutch 9 rotates the outer race 9b, for example, in the forward rotation direction shown by the solid line arrow A in FIG. 1, it integrates the inner race 9c and transmits power.
c is allowed to rotate faster than outer race 9b. Further, the one-way clutch 8 for reverse movement operates in exactly the same manner when the outer race 8b and the inner race 8c are rotated in the opposite direction to that described above. Next, to explain the control system, a negative pressure actuator 20 is connected to the sleeve 17 via a connecting rod 21, and a passage 22 from the actuator 20 is connected to the suction pipe side passage 24 or the atmosphere by energizing or de-energizing the solenoid valve 23. port 2
It can be switched to 5. A reverse switch 26 that is turned on when shifting to reverse gear and a 4WD switch 27 that is turned on when driving four wheels are connected to an OR circuit 30 via an AND circuit 29. Reference numerals 28 and 28 in the figure are indicator lamps that are connected to the ground via the switches 26 and 27, respectively, and are lit when turned on. Drive state detection means for detecting the wheel drive state are respectively formed. The 4WD switch 27 is connected to the OR circuit 30 via an AND circuit 33 along with an accelerator switch 31 that is turned on when the accelerator pedal is fully closed, and a vehicle speed switch 32 that is turned on at a predetermined vehicle speed or higher. It is connected to the solenoid valve 23 via a transistor 34. With this configuration, when the vehicle is moving forward, the reverse switch 26 and the accelerator switch 31 are turned off and the outputs of the AND circuits 29 and 33 both go to L level, so that the solenoid valve 23 is de-energized.
Then, the actuator 20 communicates with the atmospheric port 25 and becomes atmospheric pressure, so that the sleeve 17 moves rearward (to the right in FIG. 2) due to the spring force, uniting the connecting drum 16 and the forward one-way clutch 9. Join. Thus, when the clutch 6 of the transfer device 5 is engaged when the vehicle is running, the power of the drive device 1 is transmitted to the rear wheels 4 and also to the front wheels 13 via the clutch 6, the one-way clutch 9, and the propeller shaft 10. and four-wheel drive driving is performed. At this time, when the steering is performed, the front and rear wheels 13, 4
Based on the difference in turning radius, the integration of the outer race 9b and inner race 9c of the one-way clutch 9 is dissolved, and the front wheel 13 rotates quickly together with the inner race 9c, thereby smoothly turning without causing a braking phenomenon. In addition, when decelerating when moving forward with this four-wheel drive,
When the accelerator switch 31 is turned on together with the 4WD switch 27 and the vehicle speed switch 32, the AND circuit 3
The output of No. 3 becomes H level and the solenoid valve 23 is energized. Therefore, suction pipe negative pressure is introduced into the actuator 20 to move the sleeve 17 forward (to the left in FIG. 2), so that the connecting drum 16 is integrally connected to the one-way clutch 8 for reverse movement. Here, the one-way clutch 8 is such that when moving backward, the rotation of the inner race 8c is caused by the rotation of the outer race 8b.
Inner race 8 when slowing down or moving forward
Since the one-way clutch 8 is integrated when the rotation of the outer race 8b becomes faster than the outer race 8b, the front wheels 13 are kept in a directly connected state during deceleration due to the action of the one-way clutch 8. Brake is applied. Next, the reverse switch 26 is turned on as the shift operation is performed when going backwards, and if the 4WD is in the 4WD state at this time, the 4WD switch 27 is also turned on, and the output of the AND circuit 29 becomes H level, and the solenoid valve 2
3 is energized. Therefore, the one-way clutch 8 for reverse is selected as in the case of deceleration, and the one-way clutch 8 is integrated with the rotation of the gear shaft 14 in the opposite direction to that during forward movement, and power is transmitted to the front wheels 13 as well, thereby transmitting power to the four wheels. Drive running is performed. Also in this case, when the turning radius of the front wheels 13 becomes larger than that of the rear wheels 4 during steering, the integration of the outer race 8b and the inner race 8c of the one-way clutch 8 is dissolved accordingly, and when moving forward, Similarly, front wheel 1
3 rotates quickly and turns smoothly without causing any braking phenomenon. In addition, although the above-mentioned example explained the RR-based part-time method, it can also be applied to the case of the FF-based part-time method. Therefore, the switching means for the one-way clutch for forward movement and reverse movement in the above embodiment consists of the reverse switch 26 and the indicator lamp 28 described above.
2. A solenoid valve 23 that operates in response to a signal in a four-wheel drive state at least in forward or reverse travel from both a reverse detection means and a four-wheel drive state detection means consisting of a 4WD switch 27 and an indicator lamp 28; A negative pressure actuator 20 operated by a valve 23 is moved forward and backward by the actuator 20, and a one-way clutch 8 for backward movement and a one-way clutch 9 for forward movement are each transmission-connected to a connecting drum 16 fixed to a gear shaft 14 and, in turn, to a propeller shaft 10. It consists of a slide sleeve 17 and the like.

【Effect of the invention】

As is clear from the above description, according to the four-wheel drive vehicle of the present invention, during forward four-wheel drive, power is transmitted by the forward one-way clutch 9 in the same manner as in the front and rear wheel direct coupling type, and the brake is used when turning. This phenomenon is automatically avoided, and at the same time, the same effect is produced by the one-way clutch 8 for reverse movement during reverse four-wheel drive, so that the running performance of four-wheel drive is improved. Even when making the same turn, if the braking phenomenon differs as well as the rotation difference between the front and rear wheels due to road surface conditions, etc., the rotation difference is absorbed by the one-way clutches 8 and 9 accordingly, so not only the steering angle but also the road surface condition etc. are taken into consideration. Therefore, the braking phenomenon is precisely avoided, and the performance of the four-wheel drive is prevented from being unnecessarily degraded. It has a simpler structure than a system that directly connects the front and rear wheels using a truss clutch, which has a control system for avoiding braking phenomena added to the clutch, or a system that has a center differential and the necessary deflock device, and has improved transmission efficiency and reliability. It is advantageous in terms of gender, etc. Furthermore, these one-way clutches are switched by a switching means that is operated by detecting the operating state of the transfer device that is switched during four-wheel drive and the forward or reverse four-wheel drive state, for example, by a forward shift position or a reverse shift position. Therefore, unnecessary switching is not performed during two-wheel drive, and switching is ensured. Also,
It is preferable to configure the switching system of the transfer device in the same manner, since the actuator operation source and control system for both can be made common.

[Brief explanation of drawings]

FIG. 1 is a skeleton diagram schematically showing an embodiment of a four-wheel drive vehicle according to the present invention, and FIG. 2 is a configuration diagram showing the configuration and control system of the main parts. 1... Drive device, 2... Rear wheel differential device, 4...
Rear wheel, 5... Transfer device, 8... Reverse one-way clutch, 9... Forward one-way clutch, 13... Front wheel, 14... Gear shaft, 15...
Drive shaft, 16... Connection drum, 17... Slide sleeve, 20... Actuator, 23...
... Solenoid valve, 26 ... Reverse switch, 2
7...4WD switch, 31...Accelerator switch, 32...Vehicle speed switch.

Claims (1)

[Claims] 1. It is configured so that power is transmitted directly to one of the front and rear wheels, and the power is transmitted to the other through a 2.4-wheel drive switching transfer device and a one-way clutch for forward and reverse driving. , a drive state detection means for detecting a two-wheel drive or four-wheel drive state by the transfer device, a forward-reverse motion detection means for detecting a forward or reverse motion according to the forward or reverse shift position, and a forward or reverse motion detection means for detecting a forward or reverse motion by the forward or reverse shift position. The vehicle is equipped with a switching means that selectively connects the two types of one-way clutches in response to a signal indicating a four-wheel drive state in reverse, and when the four-wheel drive is in forward or reverse mode, the transfer device switches to the four-wheel drive side. A four-wheel drive vehicle characterized in that the switching means is configured so that a forward one-way clutch is transmission-connected when traveling forward, and a reverse one-way clutch is connected when traveling backward.