JP2965613B2 - Front wheel transmission for four-wheel drive vehicles - Google Patents

Description

The present invention relates to a front-wheel transmission for a four-wheel drive vehicle that increases the speed of the front wheels when the vehicle turns.

(B) Conventional technology Conventionally, in a four-wheel drive type vehicle, a transmission is interposed in a front wheel drive system, and when the turning angle of the front wheel is smaller than a set value during work, the front wheel is driven in synchronization with the rear wheel. When the turning angle exceeds a set value, a switching mechanism of the transmission is switched to drive the front wheels at a high speed.

When the vehicle having the front wheel speed increasing device is traveling at a high speed such as when traveling on a road, it is extremely dangerous if the front wheel is driven to rotate at a high speed due to a turning angle of the front wheel. It has already been done to add an electrical control device that eliminates this.

(C) Problems to be Solved by the Invention The front wheel transmission in the known four-wheel drive vehicle is
If the device that prevents the front wheel from speeding up during high-speed driving is complicated and expensive, and if its circuit or equipment breaks down, the front wheel turns rapidly in a state unexpected by the driver, which may cause an accident. Was.

(D) Means for Solving the Problems The present invention provides a transmission mechanism in which at least a traveling main transmission unit, a traveling auxiliary transmission unit having an auxiliary transmission clutch gear, and a differential mechanism interposed in a rear wheel drive system. , A transmission shaft, and a front wheel power take-off shaft, and the pinion shaft, the drive shaft, and the front wheel power take-out shaft were substantially synchronized with the rear wheel regardless of the high / low speed of the traveling auxiliary transmission portion. A first gear transmission system for driving the front wheels at a speed, and a second gear driving system for driving the front wheels at a higher speed than the rear wheels only when the traveling auxiliary transmission is switched to the lower speed side.
A gear transmission system is provided, and a clutch is interposed between the front wheel power take-out shaft and each gear of the first and second gear transmission systems mounted on the shaft, and the clutch has a front wheel disengagement angle. When the set value is less than the set value, only the clutch on the first gear transmission system is engaged, and when the set value is greater than the set value, only the clutch on the second gear transmission system is engaged with the front wheel turning angle sensor to solve the above-described problem. did.

(E) Function When the rear auxiliary transmission is switched to the high-speed side and the rear wheels are driven to rotate at high speed, the clutch on the first gear transmission system is engaged during straight running, and the front wheels are disengaged from the first gear transmission system. The aircraft is driven and driven in a 4WD state. Further, when the traveling auxiliary transmission portion is switched to the high-speed side, the second gear transmission system is in the non-transmission state, and in this state, the steering wheel is turned and the front wheels are largely turned in order to turn the aircraft largely. In this case, when the front wheel turning angle is equal to or greater than the set value, the clutch on the first gear transmission system is disengaged and then the clutch on the second gear transmission system is engaged. At this time, since the second gear transmission system is in the non-transmission state, the front wheels are not driven. That is, the aircraft is rotated in the two-wheel drive state.

When the work is performed by switching the traveling auxiliary transmission portion to the low speed side and driving the rear wheels to rotate at a low speed, the clutch on the first gear transmission system is engaged during straight running, and the front wheels are driven from the first gear transmission system. Then the aircraft runs in the 4WD state. Also, in this case, the second gear transmission system is in the transmission state, but the clutch of the first gear transmission system is engaged and the clutch of the second gear transmission system is disengaged. The front wheels are not driven from the system side.

In this state, when the front wheels are turned to rotate the aircraft, if the turning angle exceeds the set value, the clutch on the first gear transmission system is disengaged, and the clutch on the second gear transmission system is engaged,
Since the front wheels are driven from the second gear transmission system side and the front wheels are driven to rotate at high speed, the body turns rapidly.

(F) Embodiment One embodiment of the present invention will be described with reference to the drawings. In FIG. 1, the power of an engine E is transmitted to a drive shaft 3 via a propeller shaft P, an input shaft 1 and a multi-plate clutch 2, and is transmitted to the drive shaft 3. The power of the traveling main transmission unit 4 is distributed to the traveling main transmission unit 4 and the PTO transmission unit 5, and the low-speed gear 8 and the high-speed gear 9 constituting the traveling auxiliary transmission unit via the forward / reverse switching unit 6 and the ultra-low speed switching unit 7. Is transmitted to the transmission shaft A having

The pinion shaft 10 of the differential mechanism interposed in the rear wheel drive system has
The low-speed gear 8 and the high-speed gear 9 are selectively engaged with each other, and the sub-transmission clutch gear B, in which the large gear 12 and the small gear 11 are integrated, is fitted so as not to rotate relatively but to slide. The gear 13 is fixed.

The PTO sub-shaft 14, which constitutes the transmission shaft, has an idler gear 15 meshed with a front wheel drive gear 13, and a small-diameter passive gear 17 and a large-diameter drive gear 18 with which the large gear 12 is disengaged. The power take-off shaft 20 has a multi-plate clutch 21 and a clutch gear 16 meshing with the idler gear 15 and a driving gear 18 and a multi-plate A clutch gear 19 having a clutch 22 is rotatably supported, and a front wheel drive gear 13, an idler gear 15
And the front clutch gear 16 forms a first gear transmission system,
The large gear 12, the transmission gear C and the rear clutch gear 19 are the second gear.
A gear transmission system is formed.

The front wheel power take-off shaft 20 is not shown, but is transmitted to a differential mechanism in the front axle case of the front wheels, similarly to the conventional one, so that the front wheels are rotationally driven, and the front axle case or the steering transmission system has a front wheel disconnection. An angle sensor is attached, and this front wheel turning angle sensor detects when the turning angle of the front wheel exceeds a set value, and a detection signal is input to a solenoid valve provided in a hydraulic control circuit, whereby the solenoid valve is turned on. When the front wheel disconnection angle is less than a set value, the multiple disc clutch 21 is engaged and the multiple disc clutch 22 is turned off, and when the front wheel disconnection angle exceeds the set value, the multiple disc clutch 21 is disengaged and the multi-disc clutch 22 is engaged.

Then, when the auxiliary transmission clutch gear B is slid backward (to the right in the drawing) to engage the small gear 11 with the high-speed gear 9, the first gear transmission system is set in the transmission state via the pinion shaft 10, and the large gear 12 is not meshed with the passive gear 17, so the second
Since the gear transmission system is in the non-transmission state, the rear wheels are driven to rotate at high speed, and the front wheels are driven to rotate at high speed via the first gear transmission system so as to synchronize with the rear wheels. In this state, the front wheels are sharply turned to make a large turn of the body, and the turning angle becomes greater than the set value, whereby the multi-plate clutch 21 is disengaged and the second gear is engaged even if the multi-plate clutch 22 is engaged as described above. Since the transmission system is in the non-transmission state, the front wheels are not driven and are in a two-wheel drive state, so that the aircraft does not turn rapidly during high-speed traveling.

Next, the auxiliary transmission clutch gear B is slid forward to
When the transmission gear 12 meshes with the transmission gear 8 and the passive gear 17, the rear wheel rotates at a low speed, and the first and second gear transmission systems are both in the transmission state, but only the front multi-plate clutch 21 is engaged and the rear multi-wheel clutch is engaged. Since the plate clutch 22 is disengaged, the front wheels are driven to rotate at low speed so as to synchronize with the rear wheels.

If the front wheel turning angle exceeds the set value in this state, the front multiple disc clutch 12 is disengaged, and the rear multiple disc clutch 22 is engaged after the two-wheel drive state, so that the front wheels are driven to rotate at high speed.

FIG. 2 shows an example in which the multi-plate clutches 21 and 22 are replaced by ball clutches 21 'and 22'. The operation is the same as that of the above-described embodiment. In the transmission system, the front wheel drive gear 13; 23T, the idler gear 15; 35T, the clutch gear 16; 30T, and in the second gear transmission system, the large gear 1
2; 39T, passive gear 17; 20T, drive gear 18; 28T, and rear clutch gear 19; 36T, the reduction ratio of the first gear transmission system is:
23/35 × 35/38 ≒ 0.767, and the reduction ratio of the second gear transmission system is 39/20 × 28/36 ≒ 1.517, so the front wheel breaks during low-speed running with the auxiliary transmission clutch gear B switched to the low speed side. When the angle is equal to or larger than the set value, the front wheels are driven at approximately twice the rotation speed.

Note that the gear ratio of the gears can be appropriately changed as needed within the scope of the object of the invention.

(G) Effects of the Invention Since the present invention is configured as described above, when the traveling auxiliary transmission portion is switched to the low speed side and the vehicle is traveling for work, the first gear transmission when the turning angle of the front wheels exceeds a set value. The clutch on the system side is disengaged, the clutch on the second gear transmission system side is engaged, and the speed of the front wheels is increased, so that the aircraft can be rapidly turned.

Further, when the traveling auxiliary transmission is switched to the high-speed side and the vehicle is traveling on the road, if the turning angle of the front wheels is equal to or less than the set value, the clutch on the first gear transmission system is engaged and the front wheels are driven from the first gear transmission system. It can run in a four-wheel drive state.

Then, when the traveling angle of the front wheels is equal to or greater than the set value and the clutch of the second gear transmission system is engaged in a state in which the traveling auxiliary transmission portion is switched to the high speed side, the second gear transmission system is switched to the non-transmission state. As a result, the drive to the front wheels is stopped, and therefore, in this case, the front wheels do not become resistance as in the case where the front wheels are driven at a speed substantially synchronized with the rear wheels during high-speed running, and the rotation of the front wheels does not occur. It becomes a two-wheel drive state with only the free rear wheels, and can perform smooth and safe aircraft turning.

Further, the present invention provides a front wheel transmission, in particular, by providing a second gear transmission system for driving the front wheels at a speed higher than that of the rear wheels so that the transmission is transmitted only when the traveling auxiliary transmission is switched to the low speed side. It is possible to automatically shift to the two-wheel drive state when turning at high speed, thereby simplifying the front wheel transmission, and eliminating the need to increase the speed of the front wheels at high speeds as in the prior art. There is no need to add a control device, and an inexpensive front wheel transmission that operates reliably can be obtained.

[Brief description of the drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a transmission system diagram, and FIG. 2 is an exploded sectional view of a main part of another embodiment. 8 ... low-speed gear, 9 ... high-speed gear, 10 ... pinion shaft,
11 ... small gear, 12 ... large gear, 13 ... front wheel drive gear, 14
…… PRO sub shaft, 15 …… Idler gear, 16,19…
... clutch gear, 17 ... receiving gear, 18 ... drive gear, 20 ...
… Front wheel power take-out shaft, 21,22 …… Multi-plate clutch, 21 ', 22'
…… ball clutch

Claims (1)

(57) [Claims] A transmission case includes at least a traveling main transmission section (4), a traveling auxiliary transmission section having an auxiliary transmission clutch gear (B), and a pinion shaft of a differential mechanism interposed in a rear wheel drive system. 10), transmission shaft (14) and front wheel power take-out shaft (20)
And the pinion shaft (10) and the transmission shaft (1
A first gear transmission system (13), (15), which drives the front wheels at a speed substantially synchronized with the rear wheels, regardless of the height shift of the traveling auxiliary transmission portion, across the 4) and the front wheel power take-off shaft (20). (16) and the second gear transmission systems (12), (C), (1), which drive the front wheels at a higher speed than the rear wheels only when the traveling auxiliary transmission is switched to the low speed side.
9), and the gears (1) of the front wheel power take-out shaft (20) and the first and second gear transmission systems mounted on it.
Clutches (21), (22) between 6) and (19), respectively
When the front wheel turning angle is below the set value, the clutch (21) on the first gear transmission system side is interposed.
A front wheel transmission for a four-wheel drive vehicle, characterized in that it is connected to a front wheel turning angle sensor so that only the clutch (22) on the side of the second gear transmission system is engaged when the set value exceeds the set value.