JP2002067730A - Working regulation device of engine on working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a working regulation device of an engine on a working vehicle to prevent working of a travelling machine body not expected by a worker. SOLUTION: A PTO operation part 27 to operate a PTO changeover valve 22 to control driving and stopping of a hydraulic clutch 19 to change transmission and cutting to the side of a PTO shaft 18 is provided on the stopping side of the PTO shaft 18, a speed changing lever 44 to operate to change speed of hydrostatic continuously variable transmissions 6L, 6R which are driving sources of left and right travelling devices 1 to support the travelling machine body 2 are provided neutral, and a parking brake valve 17 to actuate a parking brake by controlling oil delivery to left and right hydraulic motors 11L, 11R to be driven by output from the hydrostatic transmission 6L, 6R and an engine actuation regulation means to start the engine 20 by operation of a parking brake operation part 24 to operate the parking brake valve 17 to the parking brake actuation side are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for restricting operation of an engine in a hydraulically driven work vehicle such as a crawler type traveling device.

[0002]

2. Description of the Related Art Conventionally, a hydraulically driven tractor having a crawler type left and right traveling device for supporting a traveling body and a PTO shaft which is an external output shaft of driving force. It has been known. The tractor generally includes a pair of left and right hydrostatic transmissions in which a hydraulic pump is driven by the driving force of an engine as drive sources of both traveling devices, and the above-described hydrostatic transmission in correspondence with each traveling device. And left and right hydraulic motors driven by the output from the motor.

A hydraulic clutch is provided for switching between transmission and disconnection of the driving force from the engine to the PTO shaft, and a shift lever for shifting the hydrostatic continuously variable transmission and driving and stopping of the hydraulic clutch. P to control
TO switching valve, PTO for operating the PTO switching valve
An operation unit, a parking brake valve for controlling oil supply to at least one hydraulic motor to operate a parking brake, and a parking brake operation unit for operating the parking brake valve are also provided.

By operating the hydrostatic transmission with a shift lever to vary the rotation of a hydraulic motor and thereby adjusting the rotation speed of a traveling device (crawler), the traveling body can be shifted and run. It has become. At this time, the operation of each of the above hydraulic devices is controlled by an electromagnetic valve or the like. For example, when the power is turned on (ON) by a main key to start the engine, the electromagnetic valve is activated,
In some cases, an operator may perform an unexpected operation of the traveling body such as a sudden start of the traveling body when the engine is started.

[0005]

An engine operation restricting device for a working vehicle according to the present invention for solving the above-mentioned problems comprises a left and right traveling device 1 for supporting a traveling machine body 2 and an external output shaft for driving force. A pair of left and right hydrostatic transmissions 6 having a PTO shaft 18 and a hydraulic pump being driven by a driving force of an engine 20 as a drive source of the two traveling devices 1.
L, 6R, and left and right hydraulic motors 11L, 11R driven by outputs from the hydrostatic transmissions 6L, 6R corresponding to the traveling devices 1, respectively, and a PTO shaft of driving force from the engine 20 side is provided. A hydraulic clutch 19 for switching between transmission and disconnection to the 18 side;
6R, a PTO switching valve 22 for controlling driving and stopping of the hydraulic clutch 19.
And a PTO operation unit 2 for operating the PTO switching valve 22
7, a parking brake valve 17 for controlling oil supply to at least one hydraulic motor to operate a parking brake,
In a mobile agricultural machine provided with a parking brake operation unit 24 for operating the parking brake valve 17, a PTO operation unit 27 is provided.
Is on the stop side of the PTO shaft 18 and the shift lever 44 is neutrally operated.
4 to the parking brake operating side, the engine 20
The first feature is that engine operation restricting means for enabling the start of the engine is provided.

Second, the parking brake operation section 24 is disposed near the steering handle 42.

Third, a speed switching valve 16 for switching the rotation speed of the hydraulic motors 11L, 11R is provided between the hydraulic motors 11L, 11R and the hydrostatic continuously variable transmissions 6L, 6R, and the speed switching valve 16 is operated. And a sub speed switch 26 for shifting the running speed.
6 and the parking brake switch 24 are mounted on opposite sides of the steering handle 42 therebetween.

[0008]

1 and 2 are a plan view and a rear view, respectively, of a crawler tractor to which the present invention is applied. A traveling body 2 is supported on a pair of left and right traveling apparatuses 1 of a crawler type. I have. An engine is mounted in the hood 3 in front of the traveling body 2 and the output of the engine is input to a pair of left and right hydrostatic transmissions (HST devices).
The hydraulic motor provided in each of the traveling devices 1 is driven by the hydraulic pressure output from the HST device, and the traveling device 2 is driven by the hydraulic motor.

That is, as shown in the hydraulic circuit of FIG. 3, the driving force of the engine 9 is input via the transmission 8 to the traveling hydraulic pump 7 in which the HST devices 6R and 6L are packaged. HST device 6L
Is output to the left hydraulic unit 12L for the hydraulic motor 11L of the left traveling device 1L, and the output of the other HST device 6R is input to the right hydraulic unit 12R for the hydraulic motor 11R of the right traveling device 1R.

The left and right hydraulic units 12L, 12R
Is provided with a high-low speed switching valve 13 for switching the rotation speed between high speed and low speed by switching the oil supply path of the pressure oil to the hydraulic motors 11L and 11R.
The input to the hydraulic units 12L and 12R, which have been shifted (main shift) by the HST devices 6L and 6R, are further driven in two stages by the high / low speed switching valve 13 (sub shift) to drive the 1L and 11R. The device 1 is driven so as to be able to shift by performing a main shift and a sub-shift.

A driver's seat 14 is provided on the traveling machine body 2, and a main shift lever for performing the main shift is provided in the driver's seat 14. The two hydraulic units 12
L and 12R have auxiliary transmission switching valves 16 for simultaneously switching the high and low switching valves 12L and 12R to the high or low speed side.
Is connected to the traveling hydraulic pump 7, and by operating the auxiliary speed changeover switching valve 16, both the hydraulic motors 11 </ b> L and 11 </ b> R can be simultaneously switched to the high or low speed side to drive the traveling device 1. it can.

Further, a parking brake valve 17 for holding the hydraulic motors 11L and 11R in a stopped state is connected to the two hydraulic units 12L and 12R.
The parking brake valve 17 is operated, and the hydraulic motor 11
By holding L and 11R, the traveling device 1 can be held and the parking brake can be operated.

On the other hand, as shown in FIG. 4, the tractor is provided with a PTO shaft 18 which is an external output shaft of a driving force for driving a working machine (not shown) connected rearward as in the prior art. The PTO shaft 18 is transmitted with a driving force from an output shaft 9a of the engine 9 via a hydraulic clutch 19 provided in the transmission 8, and is driven via a PTO transmission mechanism 21 independently of the traveling system. It has a structure.

The hydraulic clutch 19 is configured to be turned on and off by a PTO switching valve 22. The operation of the PTO switching valve 22, the parking brake valve 17, the high / low speed switching valve 16 and the like is controlled by an electric circuit whose wiring diagram is shown in FIG.

The electric circuit includes the PTO switching valve 22, the parking brake valve 17, the high / low speed switching valve 16,
In addition, a main key switch 2 for starting the engine 9 by inserting it into a key hole in the driver's seat 14 and rotating it.
3. A parking brake switch 24 for operating the parking brake valve 17, an auxiliary transmission switch 26 for operating the high-speed / low-speed switching valve 16, and a PTO for operating the PTO switching valve 22.
A switch 27, a parking brake lamp 28 for notifying the operation of the parking brake, and a PTO for notifying the operation of the PTO shaft 18.
A ramp 29, a high-speed lamp 31 for notifying that the sub-shift is on the high-speed side, a conductor 32 that is turned on (ON) in conjunction with an ON operation of the main key switch 23, a starter 33 of the engine, left and right driver seats The turning angle switch 34 and the like that are turned on (OFF) when the turning angle of the steering wheel provided in the steering wheel 14 becomes a predetermined value or more are provided.

A power supply (battery) is connected via a power fuse 36, and a common contact 37c of a parking brake relay 37 is connected via a main key switch 23 to a terminal on the opposite side to the power supply of the power fuse 36. . And the break contact 37 of the parking brake relay 37
b is connected to a common contact 38c of an engine start safety relay 38, and a make contact 38a of the engine start safety relay 38 is connected to a starter 33 via a neutral switch 39 which is turned on by setting a main shift lever to neutral. It is connected to the.

On the other hand, the parking brake switch 24 is a three-contact type switch, and the common terminal 24c of the parking brake switch 24 is connected to a terminal on the opposite side of the power supply of the power fuse 36 via the conductor 32 and the fuse 41. Have been. A parking lamp 28 is connected to one terminal 24a of the other terminals of the parking brake switch 24.
However, the parking brake valve 17 and the coil 37m of the parking brake safety relay 37 are connected to the other terminal 24b.

The parking lamp 28, the parking brake valve 17, and the coil 37 of the parking brake safety relay 37
The other end of m is grounded. At this time, the parking brake valve 17 is configured to release the parking brake by being energized, that is, the main key switch 2
3 and the conductor 32 is turned on, the parking brake switch 24 is switched to connect the terminal 24b to which the brake valve 17 is connected and the common terminal 24c, thereby releasing the parking brake. (The parking lamp 28 is not turned on.) Further, the parking brake switch 24 is switched to connect the terminal 24a to which the parking lamp 28 is connected to the common terminal 24c, so that the parking brake is turned on and the parking lamp 28 is activated. Lights up.

In other words, switching the parking brake switch 24 to connect the terminal 24b to which the brake valve 17 is connected to the common terminal 24c is referred to as a parking brake release operation, and the terminal 24a to which the parking lamp 28 is connected.
The switching operation to connect the terminal and the common terminal 24c can be referred to as a parking brake engagement operation.

On the other hand, the above-mentioned high / low speed changeover switch 26 is also a three-contact type switch, and has a common terminal 26c.
In addition to the high-speed lamp 31, the left and right turning angle switches 3
A high / low speed switching valve 16 is connected to the valve 4 in series. At this time, the high-low speed switching valve 16 is configured to switch the sub-shift to the high-speed side by energization. One terminal 2 of the other terminals of the high / low speed switch 26
6a is connected to the common terminal 24c of the parking brake switch 24, and the other terminal 26b is open. The other ends of the high-speed lamp 31 and the high-low speed switching valve 16 are grounded.

On the other hand, the aforementioned PTO switch 27 is a four-contact type switch. By pressing the switch and fixing the pressed state, one set of the contact 27a is set.
(The predetermined two contacts 27aa and 27ab) are connected, and the connection of the other set of contacts 27b (the remaining two contacts 27ba and 27bb) is released, and the pressed state of the switch is released (released). Thus, the connection of the set of contacts 27a that has been connected is released, and the set of contacts 27b that have been disconnected is connected.

One terminal 27aa of the terminal 27a connected by the pressing operation of the PTO switch 27 and one terminal 27ba of the terminal 27b connected by the releasing operation are both connected to the common terminal 24c of the parking brake switch 24. The other 27 of the terminals 27a connected by the pushing operation
ab is the coil 3 of the engine start safety relay 38
8m, the other 3 of the terminals 27b connected by the release operation.
7bb is connected to the PTO switching valve 22 and the PTO lamp 29.

At this time, when the PTO valve 22 is energized, the hydraulic clutch 19 is engaged and operated to transmit the driving force to the PTO shaft 18, that is, the release operation of the PTO switch 27 is applied to the PTO shaft 18. The driving force transmission (with PTO shaft) operation and the pressing operation of the PTO switch are the driving force non-transmission (PTO shaft cutting) operation to the PTO shaft 18. The PTO valve 22, PTO
The other end of the lamp 29 and the coil 38m of the engine start safety relay 38 are grounded.

The electric circuit is configured as described above.
When the main key switch 23 is turned on to start the engine 9, the parking brake relay 37 is deactivated (the coil 37m is not energized), the engine start safety relay 38 is activated, and the neutral switch 39 is turned on. It is necessary to perform ON (enter) operation, and the following three conditions are required.

First, the parking brake switch 24 is switched to the parking brake input side, and the common terminal 24c is connected to the terminal 24a on the parking lamp 28 side.
The energization of the brake valve 17 and the coil 37m of the parking brake relay 37 is cut off, and the parking brake relay 37 is deactivated, thereby connecting the common terminal 37c of the parking brake relay 37 to the break terminal 37b.

Secondly, the PTO switch 27 is pushed to release the connection of the terminal 27b on the PTO valve 22 side so that the hydraulic clutch 19 is disengaged and actuated, and the transmission of the driving force to the PTO shaft 18 is cut off. Are connected to the coil 38m of the engine start safety relay 38 to connect the common terminal 38c of the engine start safety relay 38 to the make terminal 38a. Third, the main shift lever is set to neutral, and the neutral switch 39 is turned on to operate.

When the above three conditions are met, the main key can be turned on and actuated to start the engine 20. Under this condition, when the engine 20 starts, the main shift is switched to neutral, the parking brake is operated, and the transmission of the driving force to the PTO shaft 18 is cut off. The operation of the traveling machine body 2 and the working machine that the worker (operator) does not expect, such as sudden start, driving of the PTO shaft 18, and sudden operation of the working machine due to driving of the PTO shaft 18, is prevented.

The high / low speed changeover switch 26 and the parking brake switch 24 are connected to the driver's seat 1 as shown in FIG.
4 are provided on a steering column 41, and both switches 26 and 24 are connected to each other by a steering wheel 42.
It is attached to the other side across. The high / low speed changeover switch 26 and the parking brake switch 24 are built-in lamp type switches. The high speed lamp 31 is provided in the high / low speed changeover switch 26, and the parking brake lamp 28 is provided in the parking brake switch 24.

Thus, the operator can easily operate both switches 24 and 26 from the front without greatly losing the line of sight. In particular, since both switches 24 and 26 are of a built-in lamp type, the high / low speed changeover switch 26 can be operated at high speed. Side, and that the parking brake is turned on and activated can be confirmed by lighting of the lamp, and the state of the switch can be easily confirmed.

As shown in FIG. 7, the PTO switch 27 is disposed upwardly behind the main speed change lever 44 on the side panel 43 in the driver's seat 14 so that the operator can easily operate the PTO switch 27. In addition to being able to easily check the state of the PTO switch 27, the operation of the PTO switch 27 and the operation of the main shift lever 44 can be smoothly switched, and the operability is improved. I have.

As shown in FIG. 8, in the above electrical circuit, a high / low speed switch safety relay 46 is provided, one terminal of a coil 46m of the high / low speed switch safety relay 46 is grounded, and the other terminal is connected to a high level. The relay 46 is connected to the common terminal 26c of the low-speed switch 26, and the neutral switch 3
The common terminal 46c of the high / low speed changeover switch safety relay 46 may be connected to the neutral switch 39, the break terminal 46b may be connected to the starter 33, and the make terminal may be opened between the starter 33 and the starter 33.

In this case, the high / low speed switch 26 is switched to the high speed side (the high / low speed switch valve 16 is energized).
Then, the high / low speed changeover switch safety relay 46 operates (energizes the coil 46m), the common terminal 46c and the make terminal 46a are connected, and the connection between the neutral switch 39 and the starter 33 is disconnected, so that the starter 33 is operated. You will not be able to do it.

That is, a condition that the sub-shift is switched to the low speed side is added to the above-described start condition of the engine 20, and the sub-shift is switched to the high speed side when the engine is started. 2 is prevented from running at high speed. 8, the same reference numerals as those in FIG. 5 indicate the same functions, and the detailed description thereof will be omitted.

[0034]

According to the structure of the present invention constructed as described above, in a hydraulically driven work vehicle in which the right and left traveling devices and the PTO shaft are turned on and off by independent hydraulic pressure, Since the driving of the PTO shaft is stopped at the time of starting and the parking brake is turned on and operated, there is an effect that an unexpected operation of the traveling machine body such as a sudden start of the traveling machine body is prevented.

By arranging the parking brake operation section near the steering wheel, the operation of the parking brake can be performed more easily. In particular, the traveling speed is changed by operating the speed switching valve for switching the rotation speed of the hydraulic motor. By mounting the auxiliary speed change switch and the parking brake operation unit on opposite sides of the steering handle with respect to each other, both switches can be easily operated.

[Brief description of the drawings]

FIG. 1 is a plan view of a tractor.

FIG. 2 is a rear view of the tractor.

FIG. 3 is a hydraulic circuit diagram of the tractor.

FIG. 4 is a sectional view of a main part of a driving portion of the PTO shaft.

FIG. 5 is an electrical circuit diagram of the tractor.

FIG. 6 is a side perspective view of a steering handle portion.

FIGS. 7A and 7B are a plan view and a side view of a main portion of a main speed change lever portion.

FIG. 8 is another electric circuit diagram of the tractor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Traveling device 2 Traveling body 6L HST device (hydrostatic transmission) 6R HST device (hydrostatic transmission) 11L hydraulic motor 11R hydraulic motor 18 PTO shaft 16 High / low speed switching switch (speed switching valve) 17 Parking brake valve 19 Hydraulic clutch 20 Engine 22 PTO switching valve 24 Parking brake switch (parking brake operation unit) 26 Sub-shift switch 27 PTO switch (PTO operation unit) 42 Steering handle 44 Main shift lever (shift lever)

Continued on the front page. (72) Inventor Toyoharu Endo, 667 Iida-machi, Higashi-Izumo-cho, Yatsuka-gun, Shimane Prefecture Inside Mitsubishi Agricultural Machinery Co., Ltd. (72) Inventor Tatsuhiko Nojima 667 Iya-cho, Higashi-Izumo-cho, Yatsuka-gun, Shimane 1 Mitsubishi Agricultural Machinery Co., Ltd. (72) Inventor Tadashi Nakao 667, Iya-cho, Izamo-cho, Higashi-Izumo-cho, Yatsuka-gun, Shimane 1 F-term in Mitsubishi Agricultural Machinery Co., Ltd. (Reference) 3D037 CA10 CB38 FA25 FA27 3D040 AA01 AA18 AA28 AB04 AC02 AC50 AC56 AD05 AD13 AE09 AE12 AF01

Claims (3)

[Claims] A traveling device (1) for supporting a traveling vehicle body (2) and a PTO shaft (18) as an external output shaft of driving force are provided, and as driving sources for both traveling devices (1),
A pair of left and right hydrostatic transmissions (6L) and (6R) in which a hydraulic pump is driven by the driving force of the engine (20);
Left and right hydraulic motors (11L) and (11R) driven by outputs from the hydrostatic transmissions (6L) and (6R) are provided in correspondence with each traveling device (1), and are provided on the engine (20) side. A hydraulic clutch (19) for switching transmission and disconnection of the driving force from the motor to the PTO shaft (18) side, a shift lever (44) for shifting the hydrostatic continuously variable transmissions (6L) and (6R), A PTO switching valve (22) for controlling driving and stopping of the hydraulic clutch (19);
PTO operation section (2) for operating the TO switching valve (22)
7) and a parking brake valve (1) that controls oil supply to at least one hydraulic motor to operate a parking brake.
7) and a parking brake operating unit (24) for operating the parking brake valve (17).
The PTO operation unit (27) is on the stop side of the PTO shaft (18),
Work provided with engine operation restricting means for enabling the start of the engine (20) by operating the parking brake operating section (24) toward the parking brake operating side when the shift lever (44) is neutrally operated. An operation control device for an engine in a vehicle. 2. The engine operation restricting device in a work vehicle according to claim 1, wherein the parking brake operating section (24) is arranged near the steering handle (42). The speed change valve (16) for switching the rotation speed of the hydraulic motors (11L) and (11R) is connected to the hydraulic motors (11L) and (11R) and the hydrostatic continuously variable transmission (6).
L) and (6R), and the speed switching valve (1
6) to operate the auxiliary speed change switch (2)
6), and the auxiliary shift switch (26) and the parking brake switch (24) are connected to each other by the steering handle (4).
The engine operation restricting device for a work vehicle according to claim 1 or 2, wherein the device is attached to an opposite side of (2).