JP2000033824A - Operation mechanism of pto clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple and less expensive operation mechanism of the PTO clutch giving small shock during the engagement operation of the PTO clutch and small load to PTO transmission system. SOLUTION: The rotation number control device is provided between a hydraulic cylinder 27 and a hydraulic pump 29 which supplies pressurized oil to the hydraulic cylinder 27. The hydraulic cylinder 27 operates by hydraulic pressure a PTO clutch 26 which disconnects and connects the transmission of driving power of an engine 5 to the PTO axis. The rotation number control device permits engagement operation of the hydraulic cylinder 27 which operates engaging the PTO clutch 26 when the speed of the engine 5 is smaller than the predetermined level.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PTO clutch operating mechanism for transmitting a driving force of an engine to a PTO shaft independently of a traveling system.

[0002]

2. Description of the Related Art In order to operate a connected working machine with a tractor stopped, regardless of a main clutch for connecting and disconnecting a driving force from an engine to a traveling device or the like, It is known that a PTO clutch is provided for operating the driving force on and off to a PTO shaft for a working machine. Generally, the on / off of the PTO clutch is controlled by a hydraulic cylinder.

[0003] In general, the supply of pressure oil to the hydraulic cylinder is performed through a control valve that gradually increases the hydraulic pressure. In the case of the extension operation, the hydraulic pressure of the hydraulic oil supplied to the hydraulic cylinder by the control valve gradually increases, and the hydraulic cylinder gradually operates to extend, so that there is little shock when the PTO clutch is engaged, and as described above, The load on the PTO transmission system that transmits the driving force of the engine to the PTO shaft independently of the traveling system is set to be small.

However, the mounting cost of the control valve is relatively high, and the hydraulic circuit is complicated. Therefore, it is desirable to remove the control valve in terms of cost or hydraulic circuit design. Since the oil pressure of the pressure oil supplied to the hydraulic cylinder increases rapidly, the PTO
There is a disadvantage that the shock at the time of the engagement operation of the clutch is increased and the load on the PTO transmission system is increased. The shock at the time of the engagement operation of the PTO clutch is reduced without providing a control valve. There has been a demand for a PTO clutch operating mechanism that reduces the load.

[0005]

According to the present invention, there is provided a PTO clutch operating mechanism for solving the above-mentioned problem, which transmits a driving force of an engine to a PTO shaft independently of a traveling system.
A PTO clutch 26 that connects and disconnects the transmission of the driving force to the PTO shaft is provided in the TO transmission system, and a PTO hydraulic circuit that hydraulically operates the PTO clutch 26 is provided with a PTO clutch 2.
Hydraulic cylinder 27 and hydraulic cylinder 2
7 is provided with a hydraulic pump 29 for supplying pressurized oil, and between the hydraulic cylinder 27 and the hydraulic pump 29, when the rotation speed of the engine 5 is smaller than a predetermined value, P
Hydraulic cylinder 27 that engages and operates TO clutch 26
The first feature is that a rotation speed regulating device that allows the turning-in operation is provided.

[0006] The rotation speed regulating device is provided with a hydraulic cylinder 27.
When the engine 5 is turned on and the engine 5 rotation speed is larger than a predetermined value that allows the hydraulic cylinder 27 to be turned on, an active control device that reduces the engine 5 rotation speed to be smaller than the predetermined value is provided. It has two features.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a tractor provided with a PTO clutch operating mechanism according to the present invention. The tractor has a body 1 supported by front wheels 2 and rear wheels 3 as in the prior art. An engine 5 (see FIG. 6) is provided therein, and a driver's seat 7 covered by a cabin 6 is provided substantially at the center. The driving force from the engine 5 is input to the front wheels 2 and the rear wheels 3 via a main clutch for driving (not shown) so as to be freely connected and disconnected, so that the tractor travels by the driving force. ing.

At this time, the cabin 6 in the tractor
As shown in FIG. 2, a relatively flexible and resilient cushion material 8 is provided on the left and right sides and the rear side of the lining of the rear part, and the cushion material 8 has an uneven portion having an uneven shape. In addition to the protection of the left and right sides and the rear of the head of the operator (driver) by the uneven portion 9, the reverberation of the sound in the cabin 6 is reduced, so that the inside of the cabin 6 is reduced. The noise has been reduced.

As shown in FIG. 3, one or both of the front and rear wheels 11 of the left and right front wheels 2 and the rear wheels 3 of the tractor are provided with covers 13, At this time, as shown in FIG. 4A, the outer cover 13 is formed integrally, but as shown in FIG. It is divided into a plurality (two in this embodiment), and each divided piece 1
The axle 16 is penetrated by 4a and 14b, and is detachably attached to the rim 12 side.

As shown in FIG. 3, the covers 13 and 14 can be easily attached and detached by using bolts 18 and the like on a nut 17 welded to the rim 12 of the wheel 11, as shown in FIG. I have. The covers 13 and 14 have a shape protruding smoothly from the wheel 11, and the covers 13 and 14 prevent mud from adhering to the rim 12 and the like during traveling.

On the other hand, the tractor is provided with a PTO shaft (not shown) for transmitting a driving force to a working machine (not shown) connected rearward as in the prior art.
PT provided on the transmission 21 shown in FIG.
The driving force is transmitted via the O drive shaft 22. At this time, the driving force is input to the PTO drive shaft 22 via the reduction gear 24 from the drive shaft 23 provided in the transmission 21.

The drive shaft 23 is always rotating during the operation (rotation) of the engine 5 by inputting the driving force from the engine 5 without passing through the main clutch (the driving force is input). ), But the speed reducer 24
Clutch 26 is provided between the PTO drive shaft 22 side and the PTO drive shaft 22 side.
Is provided, that is, the PTO transmission system of the above configuration for driving the PTO shaft is a PTO drive shaft 22 (PTO shaft).
The driving force is input from the engine 5 via the PTO clutch 26, and the driving force is disconnected and connected by the operation (operation) of the PTO clutch 26 regardless of the operation of the main clutch.

The PTO clutch 26 is a piston 2 of a PTO hydraulic cylinder (PTO hydraulic cylinder) 27.
The on / off operation is switched by the operation of 7a, but the pressure oil to the PTO hydraulic cylinder 27 is changed from the output of the pump 29 which sends the pressure oil to the power steering mechanism 28 side of the tractor as shown in FIG. A PTO hydraulic circuit for hydraulically operating the PTO clutch 26 by the branch valve 31, the PTO hydraulic cylinder 27, the pump 29 and the like is formed.

On the other hand, as shown in FIG. 7, a speed control lever 32 for adjusting the number of revolutions of the engine 5 is provided on the engine 5 side so as to be able to swing, as in the prior art. The moving range is regulated by stoppers 33 and 34 made of bolts, and the structure is such that the minimum rotation speed and the maximum rotation speed of the engine 5 adjusted by the speed control lever 32 are set.

On the side of the engine 5, when the speed control lever 32 swings to set the rotation speed of the engine 5 to the minimum rotation, the low speed detection switch 36 which comes into contact with the speed control lever 32 and is turned on.
Is provided via a switch mounting stay 37, that is, the low-speed detection switch 36 has a structure as a sensor that detects that the engine 5 is operating at the minimum rotation speed at which the engine 5 rotates at a predetermined low rotation speed. ing.

The PTO hydraulic cylinder 27 is driven by the pump 29 together with the power steering mechanism 28 as described above, and the pressure oil from the pump 29 branches to the power steering mechanism 28 and the PTO hydraulic cylinder 27 via the branch valve 31. The solenoid valve 38 is provided in the branch valve 31, and the supply of pressure oil to the PTO hydraulic cylinder 27 is switched by the solenoid valve 38.

That is, when the solenoid valve 38 is turned on, pressure oil is sent from the branch valve 31 to the PTO hydraulic cylinder 27, and the PTO hydraulic cylinder 27 is extended to operate and the PTO hydraulic cylinder 27 is extended.
When the clutch 26 is turned on and the solenoid valve 38 is turned off, the PTO clutch 26 is turned off by the spring 26a in the PTO clutch 26.

The driver's seat in the cabin 6 has a P
A PTO changeover switch 39 for operating the operation of the TO clutch 26 is provided. The PTO changeover switch 39 and the low-speed detection switch 36 are connected in series as shown in FIG. Switch 39
(A terminal not connected to the low-speed sensing switch 36) is connected to one end (+ terminal in the present embodiment) of the power supply 41, and one end of the low-speed sensing switch 36 (connected to the PTO switch 39). (A terminal not shown) is connected to one terminal of the solenoid valve 38.

The other end of the power supply 41 (the negative terminal in this embodiment) and the other terminal of the solenoid valve 38 are grounded. The coil 42a of the relay 42 is connected in parallel with the solenoid valve 38,
A relay switch 42b (opened when the coil 42a is not energized) of the relay 42 is connected in parallel with the low speed sensing switch 36.

By switching the PTO changeover switch 39 from OFF to ON when the low speed detection switch 36 is ON, the relay 42 (coil 42a) and the solenoid valve 38 are energized, and the solenoid valve 38 is turned ON.
And the PTO clutch 26 is engaged and activated.

At this time, when the solenoid valve 38 is energized, the relay 42 is also energized as described above, and the relay switch 42b is turned on.
Is turned off, the PTO switch 39 is
The solenoid valve 38 is energized until FF is reached, and the engagement operation of the PTO clutch 26 is continued.

That is, by turning off the PTO switch when the PTO clutch 26 is engaged, the power supply to the relay 42 and the solenoid valve 38 is cut off, the relay switch 42b is turned off, and the power supply to the solenoid valve 38 is stopped. Can be

Since the low speed detection switch 36 and the PTO switch 39 are connected in series, when the low speed detection switch 36 is OFF, the PTO switch 39 is turned off.
No power is supplied to the solenoid valve 38 irrespective of the operation of the low speed detection switch 36 and the relay 4
The on / off operation of the PTO clutch 26 {the on / off operation (extension operation) of the PTO hydraulic cylinder 27} by the engine 5
A rotation speed regulating device for regulating the rotation speed based on the rotation speed of the motor is constituted.

That is, the PTO is controlled by the rotation speed control device.
The on / off operation of the PTO clutch 26 by the changeover switch 39 is enabled only when the low-speed detection switch 36 is ON, that is, when the rotation speed of the engine 5 is sufficiently low to turn on the low-speed detection switch 36 (the minimum rotation speed). (Permissible), and after the PTO clutch 26 is engaged, the self-excitation of the relay 42 causes P
Since the ON operation of the TO clutch 26 can be continued, the rotation speed of the engine 5 can be arbitrarily changed, and the turning operation of the PTO clutch 26 can be arbitrarily performed regardless of the rotation speed of the engine 5. Can be.

As a result, the rotational speed of the engine 5 is always sufficiently low as described above (the above-described minimum rotational speed) when the PTO clutch 26 is engaged, so that the shock and the PTO transmission when the PTO clutch 26 is engaged. The load on the system is relatively small, that is, by gradually increasing the oil pressure when supplying the pressurized oil to the PTO hydraulic cylinder 27, the shock when the PTO clutch 26 is engaged and the load on the PTO transmission system are made relatively small. An operation mechanism of the PTO clutch 26 having the same effect as that of providing the control valve without providing a control valve or the like (shock when the PTO clutch 26 is engaged and relatively small load on the PTO transmission system). Is configured.

At this time, the operation mechanism of the PTO clutch 26 provided with the rotation speed regulating device having the above configuration is inexpensive because it is not necessary to provide the relatively expensive control valve. Since no piping is required, the hydraulic circuit is simplified and formed more simply. Also, the working machine connected to the PTO shaft does not rotate at the same time as the connection of the PTO clutch 26, and the rotation speed (working speed) of the working machine is arbitrarily set by the worker after the connection of the PTO clutch 26. And the controllability of the working machine is improved.

Next, another embodiment of the rotation speed control device will be described. The present embodiment can be applied to a system in which the rotation speed of the engine 5 is controlled by an electronic speed control device (electronic governor). As shown in FIG. 9, the operation of the electronic governor 46 is controlled by a microcomputer unit 47. The operation of the electronic governor 46 is controlled by a controller 48 that controls the electronic governor 46 according to an instruction from the microcomputer unit 47. 5 is configured to be adjusted.

In the present embodiment, the above-mentioned PTO changeover switch 39 is connected to the input side of the microcomputer unit 47, and a feedback signal from the controller 48 concerning the rotation speed of the engine 5 (operation of the electronic governor 46) is sent. The above-mentioned solenoid valve 38 is connected to the output side of the microcomputer unit 47, and the microcomputer unit 47 performs the following control to constitute a rotation speed regulating device.

That is, the above-mentioned rotation speed control device notifies the microcomputer unit 4 that the PTO switch 39 has been turned on.
7, the microcomputer unit 47 checks the state of the electronic governor 46 (rotation state of the engine 5) based on a feedback signal from the controller 48, and instructs the controller 48 when the engine 5 is rotated at a relatively high speed. And the engine 5 is switched to the predetermined low-speed rotation about the minimum rotation speed described above (that is, the high-speed rotation is higher than the predetermined low-speed rotation). Then, the solenoid valve 38 is turned on, and the PTO clutch 26 is turned on. Is controlled by the microcomputer unit 47 side so as to be operated.

That is, the PTO clutch 26 is engaged and operated at a low rotation speed similar to that of the above-described embodiment by the rotation speed regulating device such as the microcomputer unit 47, so that the engagement of the PTO clutch 26 is similar to that of the above-described embodiment. The shock at the time of operation and the load on the PTO transmission system described above are relatively small, and the same effect as when the control valve is provided without providing the control valve or the like (the shock at the time of the PTO clutch 26 engaging operation and the aforementioned Of the PTO clutch 26 having a relatively small load on the PTO transmission system.

In the case of the present embodiment, the above-described control can be performed by the microcomputer unit 47. Therefore, the rotation speed regulating device can be configured at a lower cost, and the operation mechanism of the PTO clutch 26 is simpler. Is composed of When the PTO clutch 26 is engaged and operated as described above under the control of the microcomputer unit 47, if the rotation speed of the engine 5 is relatively high, the engine 5 is automatically lowered and the PTO clutch 26 is engaged and operated. There is no need for the user to be more conscious of the number of revolutions of the engine 5 when connecting the PTO clutch 26 than necessary.

That is, the PTO clutch 26 is engaged and operated on the microcomputer unit 47 side (control flow) (PT
When the O5 hydraulic cylinder 27 is turned on and the engine 5 rotation speed is larger than a predetermined value that allows the PTO hydraulic cylinder 27 to be turned on, an active control function of lowering the rotation speed of the engine 5 to be lower than the predetermined value. In other words, the above-mentioned rotation speed regulating device is constituted by the microcomputer unit 47, the controller 48 and the like, and the rotation speed of the engine 5 is activated (actively) by the rotation speed regulating device as described above. ) Is provided with an active control device.

As a result, when the PTO clutch 26 is connected, the rotation speed of the engine 5 automatically becomes a predetermined low-speed rotation or lower, so that the work implement connected to the PTO shaft
The rotation speed (working speed) of the working machine is not increased at the same time when the O-clutch 26 is engaged (engagement operation).
After the clutch 26 is connected, it can be arbitrarily set by the operator, and the controllability of the working machine is improved.

In this case, it is possible and particularly easy to reduce the rotation speed of the engine 5 only when the PTO clutch 26 is connected, and then to automatically increase the rotation speed to a predetermined rotation speed. Accordingly, the worker does not need to be conscious of the number of revolutions of the engine 5, the work can be automated, and the work by the work machine can be performed more easily.

On the other hand, the low-speed sensing switch 36 is not located on the side of the speed control lever 32 as in the above-described embodiment, but on the side of the throttle lever 49 for adjusting the number of revolutions of the engine 5 provided in the driver's seat 7 as shown in FIG. It may be provided. Further, the solenoid valve 38 may be controlled as described above by detecting the rotation speed of the engine 5 from a flywheel or the like and inputting the detected rotation speed of the engine 5 to the microcomputer unit 47 side.

Further, the low speed detection switch 36 is connected to the speed control lever 32 so that the slide rod 52 slidably moving in the case 51 as shown in FIG. As shown in FIG. 11B, a projection 53 provided on the slide rod 52 is provided with a switch 54.
, And the switch 54 may be turned on.

[0037]

According to the structure of the present invention constructed as described above, the PTO clutch is engaged and operated only when the engine speed is lower than the sufficiently low predetermined value by the engine speed regulating device. Without providing a relatively expensive control valve or the like for gradually increasing the oil pressure when supplying pressure oil to the cylinder, a PTO with a small shock to the PTO clutch when the PTO clutch is engaged and a small load on the PTO transmission system is provided.
In addition to the advantage that the clutch operating mechanism can be configured simply and inexpensively, there is also an effect that the working machine connected to the PTO shaft does not rotate at the same time as the connection of the PTO clutch.

In particular, when the rotation control device is configured to lower the engine rotation speed to be lower than the predetermined value when the engine rotation speed is higher than the predetermined value when the hydraulic cylinder is activated by the active control device, The operator can engage the PTO clutch without paying attention to the engine speed more than necessary.

[Brief description of the drawings]

FIG. 1 is a side view of a tractor.

FIG. 2 is a plan sectional view of a main part of the cabin.

FIG. 3 is a sectional view of a main part of a wheel portion.

4A is a front view of an outer cover, and FIG. 4B is a front view of an inner cover.

FIG. 5 is a sectional view of a main part of the transmission.

FIG. 6 is a hydraulic circuit diagram of a PTO hydraulic circuit portion.

FIG. 7 is a schematic plan view showing a structure of a speed control lever portion.

FIG. 8 is a wiring diagram of a rotation speed regulating device.

FIG. 9 is a wiring diagram of another embodiment of the rotation speed control device.

FIG. 10 is a perspective view of a throttle lever portion.

FIGS. 11A and 11B are cross-sectional views showing another embodiment of the low-speed sensing switch.

[Explanation of symbols]

 5 Engine 26 PTO clutch 27 Hydraulic cylinder 29 Hydraulic pump

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Eisuke Takagi 667 Idai-cho, Oji-machi, Higashi-Izumo-machi, Yatsuka-gun, Shimane 1 Inside Mitsubishi Agricultural Machinery Co., Ltd. 667 1 Mitsubishi Agricultural Machinery Co., Ltd. (72) Tomonori Suyama Inventor Tomonori Suyama 667 Idaicho, Higashi-Izumo-cho, Yatsuka-gun, Shimane 1 F-term in Mitsubishi Agricultural Machinery Co., Ltd. 3D043 AA06 AA08 AB12 AB17 BC03 BC04 BC16 BD05 BD06 BF02 BF07

Claims (2)

[Claims] A PTO clutch (2) for connecting and disconnecting the transmission of the driving force to the PTO shaft with a PTO transmission system for transmitting the driving force of the engine (5) to the PTO shaft independently of the traveling system.
6), a hydraulic cylinder (27) for operating the PTO clutch (26) and the hydraulic cylinder (2) are provided in a PTO hydraulic circuit for hydraulically operating the PTO clutch (26).
7) when a hydraulic pump (29) for supplying pressurized oil is provided, and the rotational speed of the engine (5) is lower than a predetermined value between the hydraulic cylinder (27) and the hydraulic pump (29). Operating mechanism of a PTO clutch provided with a rotation speed regulating device that allows a hydraulic cylinder (27) to enter and operate the PTO clutch (26). 2. The engine according to claim 1, wherein the rotation speed regulating device comprises a hydraulic cylinder (2).
If the rotation speed of the engine (5) is larger than a predetermined value that allows the hydraulic cylinder (27) to perform the on-coming operation when the on-coming operation is performed, the active speed of the engine (5) is reduced to be lower than the predetermined value. The operating mechanism for a PTO clutch according to claim 1, further comprising a control device.