JPS6237775Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention allows the vehicle to travel along a tobacco cultivation ridge or a tea cultivation ridge while straddling the ridge.
In an agricultural vehicle that performs elevated agricultural work such as sowing, seedling planting, and harvesting, a speed change cam is provided on the flow control shaft of a travel drive hydraulic pump to interlock and connect a cam operating member connected to a travel speed change lever via a pin, The speed change cam is provided with a running neutral range in which the control shaft is stopped in a neutral range through the pin, a minute speed range in which the control shaft is moved forward and backward at a slow speed, and a normal speed range in which the control shaft is moved forward and backward at a rapid speed, and the cam operating member is controlled by the speed change lever. When operating the speed change cam to the neutral range, minute speed range, or normal speed range via the
In conjunction with this, the amount of advance and retreat of the control shaft is changed proportionally to adjust the discharge flow rate of the hydraulic pump.Compared to the conventional art, the travel neutral operating range of the gear shift lever can be made larger, and the hydraulic pressure It is possible to improve the stability of the stopping operation by neutral operation of the pump, and it is also possible to perform moving work at minute speeds such as deep plowing work, and efficient forward and backward running at general moving speeds, which is useful for various agricultural work. The purpose of the present invention is to provide a traveling transmission device for agricultural vehicles that can improve efficiency.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings. Fig. 1 is an overall left side view of the elevated agricultural vehicle, and Fig. 2 is a plan view of the entire elevated vehicle. a torso body frame 4, 4 whose front end side is swingably attached and connected to the front body frame 1;
are front axle cases 6 and 7 that are slidably attached to and detachable from both ends of the front body frame 1 via positioning pins 5.
8 and 9 are front wheels that are mounted on the lower ends of the front axle cases 4 and 4; 8 and 9 are left and right front wheel drive hydraulic motors that are attached to the upper ends of the front axle cases 4 and 4 via reduction gear cases 10 and 10; 13 and 14 are left and right rear wheels that are mounted on the lower ends of the rear axle cases 11 and 11, and 15 and 16 are Hydraulic motors for driving the left and right rear wheels are attached to the upper ends of the rear axle cases 11, 11 via reduction gear cases 10, 10, and an engine 17a is installed between the front and rear wheels 6, 13 on the outside of the left side body frame 3. Reference numeral 18 denotes a driving operation part in which a driving frame 19 is fixed between the front and rear wheels 7 and 14 on the outside of the right side body frame 3, and is equipped with a driver's seat 20, a steering wheel 21, etc., and 22 is a lower part of the driver's seat 20. Battery storage room equipped with 2
3 and 24 are right and left row hydraulic motors 9, 16 and 8 mounted in the front center of the body frame 3;
15 two hydraulic pumps for operation; 25 a hydraulic charge pump linked to the hydraulic pumps 23 and 24 via a belt; 26 the engine 17;
a and hydraulic pumps 23, 24, 25
PTO transmission case interlocked with, 27
29 is a PTO housing for taking out the rear PTO which is detachably and directionally connected to the PTO output shaft 28 on the rear side of the transmission case 26; 29 is a traveling gear shift lever which is connected to the hydraulic pumps 23 and 24 to perform traveling gear shifting operations; 30; is the PTO transmission case 2
5 is a PTO gear shift lever, 31 is a hydraulic lift provided approximately at the center of the rear body frame 2 and has a lift arm 32, and 33 is a hydraulic elevator that is pulled to the rear of the aircraft via a lower link 34 and a top link 35, and is equipped with a rotary 36. This is a rotary tilling machine, and is configured to run over tobacco cultivation ridges, tea cultivation ridges, etc., and to perform tillage work using the working machine 33.

FIG. 3 is a hydraulic circuit diagram, in which the variable displacement hydraulic pump 24 is connected to the front and rear wheels 6 disposed in the left row of the machine body,
13 hydraulic motors 8 and 15 are connected in parallel, and the hydraulic pressure supply to the hydraulic motor 8 is appropriately cut off between these hydraulic motors 8 and 15. One of the two-position and four-port manual hydraulic switching systems is used for switching between 2-wheel drive and 4-wheel drive. A valve 37 is provided. In addition, the other variable displacement hydraulic pump 2
3, the hydraulic motors 9 and 16 of the running wheels 7 and 14 disposed on the right row of the fuselage are connected in parallel, and the hydraulic pressure supply to the hydraulic motor 9 is appropriately cut off between these hydraulic motors 9 and 16. The other 2 for switching drive
A 4-port manual hydraulic switching valve 38 is provided.

Further, between the circuits of the hydraulic motor 15 and the switching valve 37 and the hydraulic motor 16 and the switching valve 38, the front and rear wheels 6, 13 and 7, 14 on the left and right sides are connected to a differential drive, differential suspension (defroc), or A 3-position, 4-boat type manual hydraulic switching valve 39, which is a hydraulic valve for switching to an emergency drive interruption (emergency) state, is provided.

In addition, the switching valves 37 and 38 and the hydraulic motor 8
Shuttle valves 40 and 41 are respectively interposed between the shuttle valves 40 and 9, and a freewheeling position 4 boat type manual hydraulic switching valve 43 is interposed in the connection circuit between the outlet sides of these shuttle valves 40 and 41 and the hydraulic oil tank 42. It is set up.

On the other hand, by operating the handle 21, the front wheels 6,
A steering cylinder 44 for performing steering control of No. 7 is connected to a hydraulic oil tank 42 via a power steering circuit 45. Also, a charge pump 25 that supplies hydraulic oil to the hydraulic pumps 23, 24 and the circuit 45, a line filter 46 in the middle of the connection circuit, and a freewheel circuit 47.
and. In addition, 48, 49, 50, 51 are quick couplers, and 52 is the switching valve 37, 38,
43 is a single 2WD/4WD switching operating lever for interlocking operation, and 53 is a travel drive mode switching operating lever for switching the switching valve 39.
The switching valves 37, 38, and 43 are constructed as rotary valves that are assembled into the same cylinder block.

As shown in FIGS. 4 to 7, hydraulic pumps 23 and 24 are arranged and fixed in the front and back on the upper front surface of the body frame 3, and a transmission arm 54 which is a cam operating member of each pump 23 and 24 is fixed. , 54 are connected to the traveling speed change lever 29 via speed change rods 55, 56, and a turnbuckle 57 is provided at the middle of the rod 56 between each arm 54, 54, so that the rod 56 is extendable and retractable. Further, cam shafts 59, 59 into which the flow rate control shafts 58, 58 of the pumps 23, 24 are slidably inserted are provided in each pump 23, 2.
4. A pin 61 that is fixed on the outside and projects through a long hole 60 in the axial direction of the camshaft 59 is implanted in the flow control shaft 58, and a speed change cam 62 is rotatably fitted to the camshaft 59. Then, the speed change arm 54 is fixed to the cam 62. Then, a cam groove 63 is formed in the speed change cam 62, and the cam groove 63
a running neutral region A in which the end of the pin 61 is engaged and the flow rate control shaft 58 is stopped and supported via the pin 61; and a small speed region B with a gentle slope.
A normal speed range C with a steep slope is formed in the cam groove 63, and by operating the speed change lever 29, the speed change cams 62, 62 are rotated via the speed change rods 55, 56. Tight pin 61, 61
to move the flow rate control shafts 58, 58 forward and backward,
It is formed so as to adjust the discharge flow rate of the hydraulic pumps 23 and 24.

The present invention is constructed as described above, and when the switching valves 37, 38, 39, 43 are in the state shown in FIG. and hydraulic motors 9 and 1 on the right row.
6 is in a so-called differential suspension (deflock) state in which the connection circuit with the hydraulic pumps 24, 2 is cut off.
3 is supplied to the left and right hydraulic motors 8, 15 and 9, 16, the pump 23 supplies the motors 8, 15, and the pump 24 supplies the motors 9, 15,
16 in forward and reverse directions as appropriate.

When the switching valve 39 is now switched in the direction a by the manual switching operation of the operating lever 53, the hydraulic motors 8 and 15 in the left row, the hydraulic motor 9 in the right row,
The 16 hydraulic pressure supply circuits are brought into communication to create a so-called differential state. And now hydraulic pump 23,2
4. Or, when an abnormality occurs in this hydraulic drive system,
When the switching valve 39 is switched in direction b by manual switching operation of the operating lever 53, the hydraulic outlet of the left row hydraulic motors 8, 15 and the right row hydraulic motors 9, 16 are switched.
The hydraulic inlets of the hydraulic motors 9 and 16 communicate with the hydraulic inlets of the hydraulic motors 8 and 15, respectively, and a closed circuit is formed between these motors 8, 9, 15, and 16, and the hydraulic oil circulates. The motors 8, 9, 15, and 16 are then in a state where they are freely rotated by external force or the like. As a result, the front wheels 6 and 7 and the rear wheels 13 and 14 can be freely rotated and the aircraft can be easily moved by external force without causing the abnormal hydraulic circuit system to cause a hydraulic brake state. It is something that can be done.

In addition, when the front and rear wheels 6, 7, 13, 14 are in the 4WD state, when the operating lever 52 is operated to switch the switching valves 37, 38, 43, the hydraulic motor 8, 9, the left and right front wheels 6, 7 are stopped and rotate freely due to an external force, etc., and the rear wheels 13, 14 are in a two-wheel drive state with only the rear wheels 13, 14 being driven. The drain oil pressure of each motor 8, 9 is increased via a switching valve 43 and a drain circuit 43a to interrupt the motor operation of each motor 8, 9.

Next, when the speed change lever 29 is operated to rotate the speed change cams 62, 62 via the speed change rods 55, 56, when the pin 61 is located in the neutral travel range A of the cam groove 63 of the cam 62, the oil pressure is increased. While the flow rate control shafts 58, 58 of the pumps 23, 24 are stopped and supported to maintain a neutral traveling state, the pin 61 moves to the minute speed range B of the cam groove 63, so that
The flow rate control shaft 58 is advanced or retracted by a small amount, and the hydraulic pump 2
By slightly changing the discharge amount of the gears 3 and 24 and moving the pin 61 forward and backward at extremely low speed, the pin 61 moves to the normal speed range C of the cam groove 63, thereby changing the displacement of the speed change lever 29 and the flow rate control shaft 58. The amount of advance and retreat is changed proportionally, and the vehicle travels forward and backward at a normal moving speed.

As shown in FIG. 8, when the cam groove 63 having a neutral running range A, a very low speed range B, and a normal speed range C is represented in a cam diagram, in the conventional cam diagram represented by a two-dot chain line, the entire cam groove 63 has a normal speed range. It is parallel to the speed range C, and therefore, in the conventional cam operation of the traveling gear shift lever, this neutral speed range is approximately one point, and the neutral support position of the lever is limited to an extremely narrow range. In the cam groove 63 of the present invention, by forming the traveling neutral region A, the neutral support position of the traveling speed change lever 29 can be set in a wide range, and the operation of adjusting the discharge amount of the hydraulic pumps 23 and 24 by the lever 29 is stabilized. It is something that can be done.

Furthermore, FIGS. 9 and 10 show another embodiment, in which a disc-shaped speed change cam 62' forming an outer cam is used instead of the speed change cam 62 and cam groove 63 forming the inner cam in the above embodiment. Provided with a flow rate control shaft 58
The eccentric position of the speed change cam 62' is rotatably supported by the pin 61 of the speed change cam 62', and the outer peripheral surface of the speed change cam 62' is brought into contact with the outer surface of the housing of the hydraulic pumps 23 and 24, and the cam is operated to the eccentric position of the speed change cam 62'. A speed change rod 56 is connected via a speed change pin 54, which is a member, and the speed change cam 62' is rotated by operating the traveling speed change lever 29 as in the above embodiment.
The hydraulic pumps 23, 2 are moved in and out by moving the flow control shaft 58 in and out.
By forming the cam diagram of the outer peripheral shape of the speed change cam 62' to match the cam groove 63 of the above embodiment, the same effect as that of the above embodiment can be obtained. In addition, by making the speed change cam 62' into a disk shape, the cam 6
2' can be easily processed and provided at low cost.

As is clear from the above embodiments, the present invention has a flow control shaft 58 of the travel drive hydraulic pumps 23, 24.
A speed change cam 62 is provided to interlock and connect the cam operating members 54, 54' connected to the travel speed change lever 29 via a pin 61, and a travel neutral region A and a travel neutral region A in which the control shaft 58 is stopped in the neutral region via the pin 61 are provided. The speed change cam 62 is provided with a minute speed range B in which it moves forward and backward at a slow speed and a normal speed range C in which it moves forward and backward at a rapid speed, and the speed change lever 29 moves the speed change cam 62 through the cam operating members 54 and 54' to the traveling neutral position. When performing a speed change operation to area A, minute speed area B, or normal speed area C, the control shaft 5
The hydraulic pump 23,
This adjusts the discharge flow rate of the hydraulic pumps 23 and 24, and allows the range of operation of the shift lever 29 to be operated in the neutral position to be larger than that of the conventional system, thereby improving the stability of the stopping operation by the neutral operation of the hydraulic pumps 23 and 24 , it is possible to stably and easily carry out running and moving work at very low speeds such as deep plowing work, and efficient forward and backward movement at general moving speeds, thereby improving efficiency in various agricultural works. The width of the neutral running area A can absorb the movement of the speed change cam 62 due to dimensional errors during machining, and the hydraulic pump 2
3 and 24 operations can be properly controlled and is extremely practical.

[Brief explanation of the drawing]

Fig. 1 is a side view of an elevated agricultural vehicle showing an embodiment of the present invention, Fig. 2 is a plan view of the same, Fig. 3 is a travel drive hydraulic circuit diagram, Fig. 4 is a side view of the main parts, Fig. 5 The figure is a plan view of the main part, Figure 6 is an enlarged sectional view of the same part, and Figure 7 is a plan view of the main part.
8 is a cam diagram, and FIGS. 9 and 10 are partially enlarged views showing other embodiments. 23, 24... Hydraulic pump, 29... Traveling speed change lever, 58... Flow rate control shaft, 62, 62'... Speed changing cam, A... Neutral traveling range, B... Minute speed range.

Claims (1)

[Scope of utility model registration request] A speed change cam 62 is provided on the flow control shaft 58 of the travel drive hydraulic pumps 23 and 24 to interlock and connect the cam operating members 54 and 54' connected to the travel speed change lever 29 via a pin 61. The speed change cam 62 is provided with a running neutral range A in which the shaft 58 is stopped in a neutral range, a very small speed range B in which the shaft 58 moves forward and backward at a slow speed, and a normal speed range C in which it moves forward and backward at a rapid speed, and the speed change lever 29 is used to operate the cam. When the speed change cam 62 is operated to shift to the neutral speed range A, the micro speed range B, or the normal speed range C via the members 54 and 54', the amount of advance and retreat of the control shaft 58 is proportionally changed in conjunction with this, and the hydraulic pump 2
1. A traveling transmission device for an agricultural vehicle, characterized in that it is configured to adjust the discharge flow rates of Nos. 3 and 24.