JPS6311483A - Four-wheel steering device - Google Patents

Abstract

PURPOSE:To make steering directions of front and rear wheels preferable by providing an interlock mechanism rotated in response to the steering of front wheels, a planetary gear mechanism having a sun gear rotated by this rotating force, and a transfer bar with one end connected at the eccentric position of one of these planetary gears. CONSTITUTION:When front wheels 27, 28 are steered, a sun gear 60 is rotated accordingly, and a planetary gear 62 is revolved around the sun gear 60 while being rotated. The moving direction of a transfer bar 56 connected at the eccentric position of this planetary gear 62 when the planetary gear 62 starts to be rotated becomes opposite to the moving direction by the subsequent revolution. Accordingly, transfer directions of a transfer valve V2 when the steering quantity of the front wheels 27, 28 is small and when it is large become opposite. By utilizing this fact, steering directions of front and rear wheels can be made same phase when a handle is slightly turned (at a low speed) and the opposite phase when it is largely turned (at a high speed).

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a four-wheel steering device that steers rear wheels in response to steering of front wheels.

(Prior Art) The conventional device shown in Fig. 5.6 connects a tie rod 5.6 to the knuckle arm 3.4 of the front wheel 1.2, and connects the tip of the tie rod 5.6 to the knuckle arm 3.4 of the front wheel 1.2. It is connected to one end of an arm member 7 provided on the body side. This arm member 7 is fixed to a rotating shaft 1o of a sector gear 9 provided in a gear box 8, and rotates together with this sector gear 9. Then, a pinion 12 fixed to the tip of an input shaft 11 of a handle (not shown) is engaged with the sector gear 9.

Therefore, when the handle is turned to rotate the pinion 12, the sector gear 9 rotates, and as the sector gear 9 rotates, the arm member 7 also rotates.

Further, a crank member 13 having a dogleg shape in plan view is provided behind the gear box 8, and this crank member is rotatable around a pin 14 provided at a bent portion thereof. One end of a transmission rod 19.2° is connected to the knack arm member 17.18 of the rear wheel 15.16, and the other end of this connecting rod 18.2° is connected to the crank member 13. ing.

The crank member 13 has a negative side longer than the other side, and the end of the longer side and the arm member 7
The other end is connected by a transmission rod 21.

Now, for example, turn the handle and move pinion 12 to arrow 2.
When rotated in two directions, the sector gear 9 that meshes with the binion 12 rotates in the direction of the arrow 23, and the arm member 7 also rotates in the direction of the arrow 23 along with the rotation axis lO.

When arm member 7 rotates in the direction of arrow 23 as described above, one tie rod 5 is pushed leftward in FIG. 5, and the other tie rod 6 is pulled leftward, so that movement causes knuckle arm 3. 4 to the front wheels l, 2,
This front wheel 1.2 is steered in the direction of arrow 24.

At this time, the other end of the arm member 7 rotates in the opposite direction to the arrow 23 shown in "1", so the transmission rod 21 is pushed in the direction of the arrow 25, and the crank member 13 is rotated clockwise in FIG. 5 about the pin 14. make it move. When the crank member 13 rotates in this way, one knuckle arm 17 is pulled,
Since the other knack arm 18 is pushed, the rear wheel 15.1
6 in the direction of arrow 26, which is the opposite side from the front wheels.

In other words, the steering directions of the front and rear wheels are in opposite phases.

Note that if you turn the handle in the opposite direction to the direction indicated by the minus sign, the front wheel l
, 2 is steered to the left, and the rear wheels 15, ! No. 6 is steered to the right, and in any case, the steered directions of the front and rear wheels are in opposite phases.

(Problems to be Solved by the Invention) In the conventional device as described above, the steering directions of the front wheels and the rear wheels are only in opposite phases, but cannot be made in the same phase.

When the vehicle speed is slow, the steering direction of the front and rear wheels is set in opposite phases, which has the advantage of improving the turning ability. However, when the vehicle is running at high speed, if the steering direction is in the opposite phase, the rear wheels will skid even more violently, impairing its maneuverability and safety.

SUMMARY OF THE INVENTION An object of the present invention is to provide a device that sets the steering directions of the front and rear wheels in the same phase at the initial stage of changing the steering wheel, and sets the steering directions in opposite phases when the steering wheel is turned significantly.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a planetary gear mechanism having an interlocking mechanism that rotates in response to steering of the front wheels, and a sun gear that rotates by the rotational force of this interlocking mechanism. , a switching gear whose one end is connected to the eccentric position of one of the planetary gears in the planetary gear mechanism, a switching valve that moves the spool according to the movement of the switching gear, and a switching valve that is controlled by operation. The vehicle is configured to include a power cylinder for steering the rear wheels, and a connecting rod that is integrated with the pulp case of the switching valve and connected to the knuckle arm on the rear wheel side.

(Operation of the present invention) When the front wheels are steered, the sun gear rotates and the planetary gears revolve around the sun gear while rotating. The switching rod connected to the eccentric position of the planetary gear moves in the opposite direction from the direction in which the planetary gear moves when the planetary gear starts to rotate.

Therefore, the switching direction of the switching valve is reversed depending on whether the amount of steering of the front wheels is small or large. By taking advantage of the fact that the switching direction is reversed, the front and rear wheels can be steered in the same phase when the steering wheel is turned a little, and in opposite phases when the steering wheel is turned a lot.

Also, it is dangerous to turn the steering wheel sharply while driving at high speed, so avoid turning the steering wheel sharply. That is, during high-speed running, the steering directions of the front and rear wheels can be made to be in the same phase.

Furthermore, when driving at low speeds, especially when tight turning ability is required, the steering wheel is turned significantly, so that the front and rear wheels can be steered in opposite phases.

(Effects of the present invention) According to the device of the present invention, the steering direction of the front and rear wheels is set in the same phase during high-speed driving when the steering wheel is turned only slightly, and the steering direction of the front and rear wheels is set in the same phase during low-speed driving when the steering wheel is turned significantly. The rudder direction can be reversed in phase.

What's more, the action of the power cylinder can power assist the steering force on the rear wheels.

(Embodiment of the present invention) In the embodiment of the present invention shown in Figs.
7.28 is provided with a knuckle arm 28.30, and a tie rod 31.3 is attached to this knuckle arm 29.30.
2 are connected.

A piston rod 33 of a power cylinder S1 for the front wheels is connected to the tie rods 31 and 32.

A rack 34 is formed on this piston rod 33, and two pinions 35.3 are mounted on the rack 34.
B is engaged.

The shaft 37 of the one pinion 35 passes through the control valve 1 that controls the front wheel power cylinder S1 and is connected to an input shaft 38, and further connects this input shaft 38 to a handle shaft 39 that rotates integrally with the handle h. It is connected.

When the handle h is turned, the rotational force is transmitted to the pinion 35 via the handle shaft 38 → input shaft 38 → shaft 37, but the rack 34 does not move due to the switching resistance at this time. Pinion 35 is better than rack 34
roll on top. Due to this transfer of the rack 34, the shirt I/37 swings, and the control valve v1 is switched to the direction of the swinging force of the shaft 37. If the handle h is now turned to the left, the pinion 35 rolls to switch the control valve v1 as described above. When the control valve V1 is switched in this way, one cylinder chamber 40 of the power cylinder S1 communicates with the pump P1, and the other cylinder chamber 41
is connected to tank T. Therefore, piston rod 3
3 moves to the right and steers the front wheels 27, 28 to the left.

On the other hand, the knuckle arm 44.45 of the rear wheel 42.43 is
It is connected to the piston rod 48 of the power cylinder S2 for the rear wheel via tie rods 48 and 47, but the rear wheel 4
One rotation arm 48 is attached to the knuckle arm 45 provided on the third side.
is fixed.

A connecting rod 50 is connected to one end of the rotating arm, and the connecting rod 50 is shaped like a cylinder and serves as a valve case 51 of the switching valve V2.

The switching valve v2 has a spool 5 attached to the valve case 51.
2 is slidably installed inside. This spool 52 is normally maintained at the neutral position shown in the figure by the action of a centering spring 53, and communicates between a pump boat 54 formed in the pulp case 51 and a tank boat 55.

A switching rod 5B is housed in the small diameter portion 51a of the pulp case 51 outside the spool 52, and a long hole 58a is formed in the switching rod 56.

Further, the shaft 57 of the pinion 36 meshed with the rack 34 is linked to the sun gear 60 of the planetary gear mechanism a via the connecting rod 58 and the rotating shaft 58. Axis 5
8 constitutes the linkage mechanism of the present invention.

The planetary gear mechanism a has a plurality of planetary gears 02 between the ring gear 81 fixed to the body of the vehicle and the sun gear 80. One of the gears 62 has a stud port 63 erected at an eccentric position, and the tip of the stud port 63 is inserted into the elongated hole 56a of the switching rod 58.

However, when the front wheels are steered to the left as described above,
The piston rod 33 moves to the right, and with this movement, the pinion 36 rotates to the left. The rotational force of the pinion 36 is transmitted to the sun gear 60 via the shaft 57, the connecting rod 58, and the rotating shaft 58, causing the sun gear 60 to rotate.

When the sun gear 60 rotates, the planetary gears 62 revolve around the sun gear 60 while rotating. The fourth figure shows the movement trajectory of the stud port 63 at this time.
It is a diagram.

Now, when the planetary gear 62 rotates in the direction of the arrow in FIG. 2, the stud port 63 moves from A to B in the initial stage of the rotation. When the stud pole 83 moves in this way, the switching cup 58 is pulled in the direction of the arrow in FIG.
The pump boat 54 of the switching valve (2) communicates with one actuator boat 04, and the tank boat 55 communicates with the other actuator boat 65.

The one actuator boat 64 communicates with one cylinder chamber 66 of the power cylinder S2, and the other actuator port 65 communicates with the other cylinder chamber 67, so that the piston rod 48 of the power cylinder S2 is connected to the right side in FIG. direction to steer the rear wheels 42, 43 to the left.

In other words, when the front wheels 27, 28 are steered to the left as described above, the sun gear 60 rotates in the direction shown in FIG. 2, causing the planet gear 62 to rotate, but in the initial stage of the rotation,
The rear wheels 42, 43 are switched in the same direction as the front wheels, and the front and rear wheels are steered in the same phase.

When the rear wheels 42, 43 are steered as described above, this is fed back to the switching valve v2 via the rotary arm 48, so that the relative relationship between the pulp case 51 and the spool 52 is adjusted to the neutral position shown in the figure. , and the relevant switching valve v2
functions as a servo valve.

Therefore, the steering angle of the rear wheels is 42.43, and the steering angle of the front wheels is 27.28.
is proportional to the steering angle.

Furthermore, as is clear from the above, when the stuffed port 63 moves from A to B, in other words, the handle h is turned only a little! /J, the steering directions of the front and rear wheels are in the same phase.

However, when the steering angle of the front wheels is increased by turning the steering wheel h greatly, the number of revolutions I11 in which the planetary gear 62 revolves around the sun gear 60 increases accordingly, so the stud port 63 moves from C to D. . When the stud port 63 moves from C to D in this manner, the switching cup 56 is pushed to the right in FIG. 3, and the spool 52 is also moved to the right. By moving the spool 52 in the right direction, the pump boat 54 and the other actuator port 1 and 65 communicate with each other, and the tank boat 55 and one actuator port 64 communicate with each other.

Therefore, the piston rod 48 of the power cylinder S2
moves to the left, rear wheel 42.43, front wheel 27.28
Turn the wheel in the opposite direction. In other words, in the process of the stud port 63 moving from C to D, the steering directions of the front and rear wheels are in opposite phases.

In this case as well, the steering angle of the rear wheels is proportional to the switching amount of the steering wheel h, which is the same as when the steering directions of the front and rear wheels are in the same phase.

Furthermore, even when the front wheels are steered to the right by turning the steering wheel h in the opposite direction, the principle is exactly the same, only the movement of each component is reversed.

[Brief explanation of the drawing]

Drawings 1 to 4 show embodiments of this invention.
The figure is a schematic diagram of the mechanism, Figure 2 is a sectional view of the planetary gear mechanism, and Figure 3 is a sectional view of the planetary gear mechanism.
The figure is a sectional view of the switching valve, Figure 4 is an explanatory diagram showing the movement locus of the stud port, Figures 5 and 6 show the conventional device, Figure 5 is a schematic diagram of the mechanism, and Figure 6 is the gear. It is a top view of a box part. 27.28...Front wheel, h...Handle, 44.45
...Knuckle arm, S2...Power cylinder for rear wheel, 50...Connecting rod, v2...Switching valve, 51...Valve case, 58...Switching rod, a
...Planetary gear mechanism, 60...Sun gear, 62...
planetary gear.

Claims (1)

[Claims] A planetary gear mechanism that has an interlocking mechanism that rotates in response to steering of the front wheels, a sun gear that rotates by the rotational force of this interlocking mechanism, and a switching mechanism that has one end connected to the eccentric position of one of the planetary gears of the planetary gear mechanism. A switching valve that moves a spool according to the movement of the switching rod, a power cylinder for steering the rear wheels that is controlled by the switching operation of the switching valve, and a valve case of the switching valve are integrally constructed. , and a connecting rod connected to the knuckle arm on the rear wheel side.