JPS6313874B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides steering control that is performed by controlling side clutches and brakes provided on the left and right running sections in agricultural machinery, construction machinery, etc. that travel by driving the left and right running sections. The present invention relates to a power steering operation device that uses a pressure control method using hydraulic pressure.

The power steering operating device of the above-mentioned form is
For example, to perform direction change operation control, first disconnect the side clutch of the running section on the inside side in the turning direction, and then apply the brake to the running section on the disconnected side. However, this operation requires two levers on the left and right running parts, one for operating the side clutch and one for operating the brake, so a total of four levers are required, and the mechanical power steering operation device is There is a problem that it becomes complicated and causes many malfunctions. From this, the operating lever is tilted in two directions, left and right and front and back, and the side clutch is controlled by tilting in one direction.
A means has been developed for controlling the operation of the brake by rotating the brake in the other direction. However, this method controls the side clutch to be "disengaged" and the brake to be applied subsequently.
It is necessary to change the direction of tilting and rotation of the operating lever, resulting in the inconvenience that the timing of applying the brake may be delayed.

In addition, in the conventional means, the operating lever is connected to the brake operating mechanism via a link mechanism or wire, so play occurring in the connecting portion of the link mechanism or wire may cause the brake to operate. The problem is that the brakes are activated in stages, making it difficult to adjust the brakes gradually so that there is no shock.

In addition, in order to control the operation of the brake so that the effectiveness of the brake gradually increases, a pressure proportional control valve is used, and the solenoid that operates the valve is controlled by a proportional control signal proportional to the rotation angle of the operating lever. Electrical means for closing the pressure proportional control valve according to the rotation angle of the operating lever is also known.
This method is not only expensive because it requires various devices, but also completely cuts off the pressure in the hydraulic circuit that operates the brakes from the operating lever, making it difficult to rotate the operating lever to apply the brakes. There is a problem in that the reaction force due to the increase in pressure in the hydraulic circuit when the brake is applied is not transmitted to the operating lever, and the effectiveness of the brake cannot be adjusted based on the pressure sensed via the operating lever.

The present invention has been made to solve these problems occurring in conventional means, and allows the side clutch and brake of the running section to be controlled in the direction of tilting rotation using a single operating lever. Brakes are now operated continuously without switching, and the brakes are now controlled mechanically so that the effectiveness of the brakes can be controlled manually by sensing the reaction force of the hydraulic pressure transmitted to the control lever. However, it is an object of the present invention to provide a new means that enables control to gradually apply the brakes more strongly without causing a shock due to play in the connecting parts of the actuating mechanism.

In the present invention, as a means for achieving this object, one power steering lever is mounted on the frame so as to be tiltable and rotatable by means of a rotation fulcrum provided at an intermediate portion in the longitudinal direction of the power steering lever. Stack,
An operating member is provided at the middle part of the power steering lever to turn on and off a side clutch control switch provided on the frame body by tilting rotation, and the lower end of the power steering lever is provided with an operating member that turns on and off a side clutch control switch provided on the frame body. A horizontal pressing rod is provided that extends long in the direction of tilting rotation by the rotational fulcrum of the steering lever, and the lower surface side of the pressing rod is connected to the valve of the throttle valve for brake control disposed below the frame. This invention proposes a power steering operating device characterized by being brought into contact with the head.

Next, embodiments will be described in detail with reference to the drawings.

In Fig. 1, a is the drive shaft of the left running section;
a' is the drive shaft of the right running section, b is the side clutch of the left running section, b' is the side clutch of the right running section, c is the brake of the left running section, and the brake of the right running section is shown in the drawing. It is omitted here.

The side clutches b, b' are capable of engaging and disengaging from the side clutch gears 1, 1, which are constantly connected to the drive shafts a, a' of the left and right running sections via drive gears 4, 4, and these gears 1, 1. The side clutch gears 1, 1 of the center gear 3 are normally engaged with the center gear 3 by the biasing force of the coil springs 2, 2, and the drive shafts a, a of the left and right running sections are connected to each other. ' is always engaged with drive gears 4, 4 provided at .

Further, the brake c includes a brake shoe 9 that is fixedly supported on the vehicle body frame f and expands and contracts, and a brake drum that faces the brake shoe 9.

Reference numerals 5 and 5 designate shaft cylinders that are spline-fitted with the side clutch gears 1 and 1, and the shaft 6 of the center gear 3 is fitted into the inner bore of the shaft cylinders 5 and 5, and the shaft 6 of the center gear 3 is inserted into the shaft. A brake drum 7 of a brake c (the brake c on the right side is the same as the brake c on the left side, so it is omitted) is fixed to each outer end of the shaft cylinders 5,5. 8, 8 are the shaft cylinders 5, 5
This is a bearing that supports the shaft.

Reference numerals 10 and 10 are actuating rods that disengage the side clutch gears 1 and 1 from the center gear 3 and operate the side clutch gears 1 and 1 in the "off" state.
Fork-shaped fitting parts 10a, 10a that fit into the outer grooves 1a, 1a and rods 11, 11
The abutment pieces 10b, 10b abut against the lower ends of the abutting pieces 10a and 10b form an angular side surface, and are rotatably pivoted by pins 10c, 10c. 12 is a cylindrical body that guides the rod 11 up and down.

13 is a rotating arm that pushes down the rod 11, and as shown in FIG.
4 and extends to one side, and has an abutment surface 13a on its lower edge that abuts against the upper end of the rod 11, and an abutment surface 13b on its upper edge that abuts against the lower end of the piston rod 15. is formed.

As shown in FIG. 1, a link mechanism 16 is provided at the outer end of the rotation center shaft 14, and is connected to the brake shoe 9, and moves the brake shoe in synchronization with the lowering of the rod 11. 9 expansion operations are possible.

Piston 17 at the upper end of the piston rod 15
is adapted to slide within a double-acting cylinder 18 using hydraulic pressure.

19 is a solenoid valve, 20 is the valve 19
This is a circuit that opens at the end of the cylinder 18 in order to feed oil into the cylinder 18 and discharge the oil in the cylinder 18 by switching. A groove 18a for releasing oil is formed in the circumferential wall of the cylinder 18, and a circuit 21 for brake operation is installed therein.
are communicating.

In FIG. 5, the solenoid valve 19 is an open center valve with solenoids 19a, 19a attached to both ends. Each solenoid 19a, 19a is connected to be energized by a switch 29, 29 which is turned on by tilting the power steering lever 22.

The circuit 21 for brake operation is provided with a throttle valve 23 in the middle of which the flow rate can be adjusted by the power steering lever 22, and is open to a tank 24.

The power steering lever 22 has a grip portion 22a at its upper end, and a pressing rod 22b at its lower end in an inverted T-shape.
Furthermore, as shown in FIG.
5, the coil spring 2 is arranged to vertically penetrate through the frame 25, and the actuating member 22c is housed in a spring chamber 25a formed in the frame 25.
6, it is held by the frame 25 so as to be tiltable and rotatable.

That is, the through hole 27 of the top plate 27 of the spring chamber 25a
a has a diameter smaller than that of the through hole 28a of the bottom plate 28 of the spring chamber 25a, and the coil spring 26 is wound into a conical shape, and the coil spring 26 can be bent freely around the through hole 27a of the top plate 27 as a fulcrum. It is held so that it can rotate at an angle.

A pair of switches (micro switches) 29, 29 are attached to the left and right sides of the upper surface of the top plate 27, and the operating pieces 29a, 29a of the switches are attached to the left and right sides of the upper surface of the top plate 27.
Although the actuating member 22 can pass through the spring chamber 25a and advance upwardly through the spring chamber 25a, in the normal state, the actuating member 22
c, holding the switches 29, 29 off.

As shown in FIGS. 3 and 4, the pressing rod 22b provided at the lower end of the power steering lever 22 is formed to be long in the horizontal direction along the left-right direction, which is the direction of tilting rotation of the power steering lever 22. The valve head 30 of the throttle valve 23 is biased against the lower surface of the valve head 30 . The end surface of the valve head 30 is an arcuate surface.

As shown in FIG. 4, the throttle valve 23 adjusts the flow rate by moving a needle 32 forward and backward into the circuit 21.
The upper end is connected to the lower end neck of the valve head 30 and the spring 3.
3 is interposed and connected.

In FIG. 5, 34 is a hydraulic pump.

The thus constructed embodiment device operates as follows.

First, hold the grip part 22a of the power steering lever 22 and swing it to the left to move the power steering lever 22 as shown in FIG.
If it is tilted to the left, the actuating member 22c and the actuating piece 29a of the left switch 29 are separated, the switch 29 is turned on, and the left solenoid 19a of the solenoid valve 19 is energized, as shown in FIG. Then, the valve 19 is moved to the right, and oil is sent from the tank 24 to the left cylinder 18 via the circuit 20 by the hydraulic pump 34, and the piston 17 is moved to the right.
Press to advance the piston rod 15.

As the piston rod 15 advances,
As shown in FIGS. 1 and 2, the rotating arm 13 rotates counterclockwise to push down the rod 11, thereby rotating the left operating rod 10 clockwise to the left side. Pull side clutch gear 1 of side clutch b away from center gear 3 to disengage side clutch b. This operation is performed while the upper end surface of the piston 17 is lowered to the groove 18a of the cylinder 18. That is, the operation is performed in a state in which the circuit 21 that controls the operation of the brake c is closed by the piston 17.

Next, when the piston 17 further descends due to the pressure of the oil fed into the cylinder 18 and reaches the groove 18a, the oil fed into the cylinder 18 is absorbed into the groove 18a.
8 a to the tank 24 via the circuit 21 for actuation of the brake c, so that the piston 17 is in the groove 18
It does not descend further than the position a reached, but remains at that position, and the brake c is kept inactive.

Next, when the power steering lever 22 is tilted and rotated further to the left, the horizontal pressing rod 22b provided at the lower end moves together with the power steering lever 22 in the rotation direction of the pressing rod 22b. The contact portion of the lower throttle valve 23 with the upper surface of the valve head 30 is sequentially displaced in the rotational direction. As a result, as shown in FIG. 6, the valve head 30 on the lower surface of the pressing rod 22b
The distance l from the contact point P with respect to the front of the power steering lever 22 to the rotational fulcrum O of the power steering lever 22 gradually increases, and the valve head 30 of the throttle valve 23 is pushed downward by the length of this distance l. , the needle 32 is advanced into the circuit 21 against the bias of the spring 33, and the flow rate of oil flowing through the circuit 21 is gradually reduced.

As a result, the pressure of the oil in the cylinder 18 rises again, and this pressure causes the piston 17 to descend, lowering the piston rod 15 and rotating the rotating arm 13. The link mechanism 16 is actuated via the dynamic center shaft 14, and the brake shoe 9 is expanded to come into pressure contact with the brake drum 7, thereby putting the brake c into an operating state.

The operation of this brake c, that is, the amount of operation that expands the brake shoe 9 becomes larger as the flow rate of oil in the circuit 21 is throttled by the throttle valve 23 and the pressure of oil in the cylinder 18 is increased. valve 23
The amount of throttling becomes larger as the amount of tilt rotation of the power steering lever 22 is increased and the amount of displacement of the pressing rod 22b is increased. The pressing operation of the valve head 30 by the pressing rod 22b that increases the amount of restriction is achieved by sliding the pressing rod 22b sideways to the valve head 30 while changing its posture to be oblique to the valve head 30.
The contact point P of its lower surface with the upper surface of the valve head 30 and the rotation fulcrum O of the power steering lever 22
This is done by gradually increasing the distance 1 to 1, so that there is no play in the operation and the increasing tendency of the pushing amount becomes gradually steeper.

Therefore, by adjusting the speed and angle of inclination of the power steering lever 22, the effectiveness of the brake can be smoothly and precisely adjusted. Moreover, as the needle 32 is advanced into the circuit 21 to reduce the flow rate, the pressure inside the circuit 21 increases and the reaction force pushing the needle 32 increases. The operating load when applying the brake c is proportional to the pressure for applying the brake c, and the effectiveness of the brake c can be adjusted appropriately by feeling the operating load.

As explained above, in the power steering operating device according to the present invention, the frame body 25 mounts one power steering lever 22 so as to be tiltable and rotatable by a rotation fulcrum provided at an intermediate portion in the longitudinal direction. An operating member 22c is provided in the middle of the power steering lever 22 to turn on and off the side clutch control switches 29, 29 provided on the frame body 25 by rotating the power steering lever 22. The lower end of the lever 22 is provided with a horizontal pressing rod 22b that extends long in the direction of the tilting rotation of the power steering lever 22 by the rotational fulcrum, and the lower surface side of the pressing rod 22b is connected to the frame 25. Since it is configured to abut against the valve head 30 of the throttle valve 23 for brake control disposed below, the side clutch of the running section and the brake can be controlled by operating one power steering lever 22. , the tilting rotation of the power steering lever 22 is performed continuously without changing the direction of rotation, and the throttle valve 23 by the pressing rod 22b is used to apply the brake.
The pushing operation to push in the valve head 30 of the press rod 22
b slides sideways while changing its attitude diagonally with respect to the valve head, the contact point P of the lower surface of the pressing rod 22b with the upper surface of the valve head 30 and the pivot point O of the power steering lever 22 are This is done by increasing the distance l, so
It is now possible to control the brakes in a state where there is no play in the operation and the tendency of increase in the amount of pushing becomes gradually steeper, and the brake effectiveness can be controlled smoothly and precisely. Adjustments can be made accurately using the load for operating the power steering lever 22 as a clue.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram of a power steering operating device embodying the present invention, Fig. 2 is a side view of the operating portion of the above operating device connected to the piston rod, and Fig. 3 A and B are power steering operating devices of the same operating device. A partially broken explanatory diagram of the action of the steering lever part, Fig. 4 is a longitudinal sectional view of the throttle valve connected to the power steering lever as above, Fig. 5 is a hydraulic circuit diagram of the operating device as above, and Fig. 6 is an explanation of the action. It is a diagram. Explanation of drawing symbols, a, a'...drive shaft, b, b'...
...Side clutch, c...Brake, f...Vehicle frame, 1...Side clutch gear, 1a...
Groove, 2... Coil spring, 3... Center gear,
4... Drive gear, 5... Shaft cylinder, 6... Shaft, 7...
Brake drum, 8...bearing, 9...brake shoe, 10...operating rod, 10a...fitting part, 10b...matching piece, 10c...pin, 11...
... Rod, 12 ... Cylindrical body, 13 ... Rotating arm,
13a, 13b...Abutment surface, 14...Rotation center axis, 15...Piston rod, 16...Link mechanism, 17...Piston, 18...Cylinder, 18
a...Groove, 19...Solenoid valve, 19a...
... Solenoid, 20 ... Circuit, 21 ... Circuit for brake operation, 22 ... Power steering lever, 22a ... Gripping part, 22b ... Horizontal pressing rod, 22c ... Operating member, 23 ... Throttle valve, 24
... Tank, 25 ... Frame body, 25a ... Spring chamber,
26...Coil spring, 27...Top plate, 27a...
Through hole, 28... Bottom plate, 28a... Through hole, 29
...Switch, 29a ... Actuation piece, 30 ... Valve head, 32 ... Needle, 33 ... Spring, 3
4...Hydraulic pump, P...Contact point, O...Rotation fulcrum, l...Distance.

Claims (1)

[Claims] 1 One power steering lever 22 is mounted on the frame 25 so as to be tiltable and rotatable by a rotation fulcrum provided at an intermediate portion in the longitudinal direction of the power steering lever 22. An operating member 22c is provided at the lower end of the power steering lever 22 to turn on and off switches 29, 29 for controlling the side clutches provided on the frame body 25 by rotation. A horizontal pressing rod 22b extending long in the direction of tilting rotation by the rotation fulcrum is provided, and the lower surface side of the pressing rod 22b is connected to the frame 25.
Throttle valve 23 for brake control located below
A power steering operating device, characterized in that the power steering operating device is brought into abutment with a valve head 30 of.