JPH0529834U - Power take-off device for work vehicle - Google Patents

Abstract

(57) [Summary] [Purpose] The input gear 5 after the clutch 3 of the work vehicle is disengaged.
Simplifies the structure of the power take-out device that takes out the power by shifting operation, and reduces the cost required for manufacturing.
Prevents the intermittent mechanism from operating due to carelessness and error, and improves work safety. [Structure] The master cylinder 13 of a hydraulic operation system 33 for power take-out is operated by a manual lever 17,
Is detected by the lever switch 27,
Upon receipt of this detection signal, the control valve 24 is operated to connect the input gear 5 to the traveling power transmission system via the fluid pressure cylinder 22.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to a power take-off device for taking out engine power from a power transmission system after a clutch in a work vehicle, and is an improvement of an input power intermittent mechanism.

[0002]

[Prior Art]

 Generally, in the power take-off device provided in the power transmission system after the clutch in the work vehicle, after the clutch is disengaged, the input gear is shifted to the connected position, and the clutch is returned to the connected state again to release the power. It is designed to be taken out. In order to perform such a series of operations at a position away from the driver's seat, for example, in the vicinity of a working machine, it is known, for example, from Japanese Patent Publication No. Sho 60-13845 that the clutch is switched and the input gear is automatically shifted. Has been.

Here, the clutch pedal can be switched by a solenoid, and the input gear can be shifted by a hydraulic cylinder. The operation of the hydraulic cylinder is controlled by switching the electromagnetically operated control valve, and the solenoid and control valve are switched by turning on the start switch.

On the other hand, there is also one that switches the clutch by utilizing a hydraulic operating system that transmits the operation of the clutch pedal to the clutch (see Japanese Patent Application Laid-Open No. 2-102829). In this device, a second master cylinder for the power take-off device is provided separately from the first master cylinder that works in conjunction with the clutch pedal, and its communication passage is connected to the communication passage of the pedal system via a switching valve. The second master cylinder is operated by a fluid pressure cylinder, and its operation is controlled by an electromagnetically operated control valve. The input gear is switched using a fluid pressure cylinder and an electromagnetically operated control valve. Even in this case, the control valve is switched by operating the start switch to operate the fluid pressure cylinder and the second master cylinder. Further, the switch is turned on by using the switching operation of the second master cylinder, the control valve for the input gear is switched, the fluid pressure cylinder is operated, and the gear shift is performed.

[0005]

[Problems to be solved by the device]

 In the former device, the solenoid and the hydraulic cylinder operate almost simultaneously. That is, the input gear shift operation is performed almost at the same time as the clutch disengagement. Therefore, the gear shift is performed before the inertia rotation of the gear to be connected is stopped, which causes disadvantages such as generation of mesh noise and premature wear of gear teeth. There is also the inconvenience of having to turn off the ignition key switch when disconnecting the input gear from the power system.

In this respect, in the latter device, since the fluid pressure cylinder for gear shift starts the operation after the first master cylinder is completely operated and the clutch is disengaged, the above-mentioned problems occur. There is no.

However, on the other hand, since the operation of the second master cylinder and the shift lever for the input gear are both performed by the fluid pressure cylinder and the electromagnetically operated control valve, the structure is complicated and the extraction power is intermittent. The cost of the mechanism is high. In addition, there is a risk that the start switch will be erroneously turned on, and there is a problem in terms of safety depending on the type of work machine driven by the power take-out device.

The present invention relates to a disconnection mechanism of an extraction power for shifting the input gear after the clutch is disengaged, which simplifies the structure to reduce the manufacturing cost, and further, the disconnection mechanism due to inattention or error. The purpose is to prevent operation and improve work safety.

[0009]

[Means for Solving the Problems]

 In order to achieve the above object, in the present invention, a power take-off mechanism is provided in the traveling power transmission system after the clutch, which connects and disconnects the engine power to the wheels, and the first hydraulic pressure that connects and disconnects the clutch is interlocked with the clutch pedal. Presumed to be a power take-out device for a work vehicle equipped with an operating system, a second hydraulic operating system for intermittently operating the clutch in conjunction with a manual lever, and a gear operating system for switching the input gear of the power take-out mechanism. Is.

The second hydraulic operating system has a master cylinder that is operated by a manual lever, the operating oil passage of the master cylinder is connected to the operating portion of the clutch via a switching valve, and the clutch pedal and The clutch is disengaged by both manual levers.

The gear operating system is an electromagnetically operated type that controls a fluid pressure cylinder that switches a shift lever for switching an input gear, a fluid source, and a supply of a working fluid from the fluid source to the fluid pressure cylinder. It is configured to include a control valve.

Further, a lever switch for detecting that the manual lever has been switched to the clutch disengagement position, and the input gear is connected to the traveling power transmission system after the clutch is disengaged by the operation of the manual lever based on the detection signal of the lever switch. And a control means for switching and controlling the control valve so as to be connected.

[0013]

[Action]

 According to the above configuration, power extraction from the traveling power transmission system is started by switching the manual lever, and the clutch is disengaged by the hydraulic oil pressurized in the master cylinder. The gear operation system starts operation after detecting that the manual lever has switched to the clutch disengagement position, and causes the working fluid to act on the fluid pressure cylinder by switching the control valve, switching the shift lever and running the input gear. Connect to the power transmission system. After that, the manual lever is returned to the standby position and the clutch is engaged, and the engine power is transmitted to the power take-out mechanism via the traveling power transmission system. The control valve continues to maintain the switching state unless a new operation command is transmitted.

As described above, in the mode in which the master cylinder is operated by the manual lever, the number of constituent members can be reduced as compared with the fully-automatic intermittent mechanism of the extraction power. Moreover, unless the operator operates with a clear intention, the manual lever cannot be switched, so that the operation of the power take-out mechanism due to carelessness or error can be prevented.

[0015]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a power takeoff device according to an embodiment of the present invention. In FIG. 1, reference numeral 1 is an engine mounted on a work vehicle, 2 is a transmission for shifting, and 3 is a clutch for connecting and disconnecting between an engine 1 and a transmission 2. The clutch 3 has first and second clutches as will be described later. 2 The hydraulic operation systems 32 and 33 are independently connected and disconnected. Reference numeral 4 denotes a power take-out mechanism provided on the outer surface of the transmission 2. The power take-out mechanism 4 operates the input gear 5 by a gear operation system 34 (see FIG. 1) as shown in FIG. The gear 2a in the transmission 2 is meshed or disengaged from the gear 2a to drive or stop the drive source 6 for the working machine connected to the output shaft 4a. The drive source 6 is a hydraulic pump, a hydraulic motor, or the like.

The first hydraulic operation system 32 switches the first master cylinder 8 which is operated by depressing the clutch pedal 7, the hydraulic oil passage 9 thereof, and the clutch lever 10 for connecting and disconnecting the clutch 3. It comprises a booster 11 which is an operating part. On the other hand, the second hydraulic operation system 33 comprises a second master cylinder 13 arranged near the working machine and a hydraulic oil passage 14 for the second master cylinder 13. The hydraulic oil passage 14 is connected to the booster 11 via a switching valve 15. It is connected to the. The switching valve 15 is provided so that the working oil supplied from each of the master cylinders 8 and 13 acts only on the booster 11. In order to operate the second master cylinder 13, a manual lever 17 is connected to the operation rod 16 of the second master cylinder 13. The manual lever 17 is swingably supported by a bracket 18 and is switched between a standby position shown by a solid line in FIG. 1 and a clutch disengagement position shown by a virtual line.

The gear operating system 34 includes a vacuum source (fluid source) including a vacuum pump 20 that generates a vacuum and a vacuum tank 21 that stores the vacuum, a vacuum cylinder 22 (fluid pressure cylinder) that operates by vacuum pressure, A shift lever 25 provided in the power take-off mechanism 4 is provided in the vacuum passage 23 between the vacuum tank 21 and the vacuum cylinder 22, and is composed of an electromagnetically-operated control valve 24 for controlling the operation of the vacuum cylinder 22. To shift the input gear 5. The control valve 24 normally shuts off the vacuum passage 23, communicates the vacuum passage 23 only when the spool 24a is switched by electromagnetic force, and applies a vacuum pressure to the vacuum cylinder 22.

In order to shift the input gear 5 after the clutch 3 is disengaged, a lever switch 27 that detects that the manual lever 17 has been switched to the clutch disengaged position (the position shown by a virtual line in the figure) is provided. The manual lever 17 is provided so as to face the lower end swing trajectory range. Reference numeral 28 is a control device for switching and controlling the control valve 24, and the lever switch 27 is connected to the control device 28. When the lever switch 27 is switched by the manual lever 17 to generate a detection signal, the control device 28 supplies an operating current to the exciting coil 24a of the control valve 24 to switch the connection state of each port. Reference numeral 30 is an ignition key switch.

FIG. 3 shows a portion related to the control of the exciting coil 24 a of the lever switch 27 and the control valve 24 in the control device 28. In the figure, R1, R2 and R3 are relay coils, r1, r2 and r3 are their open / close contacts, T is a timer and t is their timer contacts. The relay coils R1 and R3 are connected to the first relay circuit C1, while the relay coil R2, the timer T and the exciting coil 24a are connected to the second relay circuit C2.

To explain the operation of the control device 28, when the lever switch 27 is operated by the switching operation of the manual lever 17 to the clutch disengagement position, the relay coil R1 is excited and the normally open contact r1 is turned on, The normally closed contact r1 is turned off, the relay coil R2 is excited, and the normally open contact is turned on, while the normally closed contact r2 is turned off. Then, after a lapse of a predetermined time after the timer T is activated, the exciting coil 24a of the control valve 24 is excited via the turning on of the timer contact t, the control valve 24 is switched from the state of FIG. Are connected. In this state, the relay coils R1 and R2 are held by themselves, while the relay coil R3 remains in the demagnetized state.

Subsequently, when the manual lever 17 is released and returned to the standby position, the lever switch 27 is turned off and the relay coil R1 is demagnetized, but the relay coil R2 is still held by itself. Therefore, the exciting coil 24a remains in the excited state, and the power take-out mechanism 4 maintains the connected state.

After that, when the manual lever 17 is operated again to the clutch disengaged position, the lever switch 27 is operated, the relay coil R1 is excited, the normally open contact r1 is turned on, and the normally closed contact r1 is turned off, and the relay The coil R3 is excited to turn on the normally open contact r3, while the normally closed contact r3 is turned off. As a result, the relay coil R 2 is demagnetized and the exciting coil 24a is demagnetized, and the control valve 24 returns to the state of FIG. 1 to open the vacuum cylinder 22 to the atmosphere. That is, the shift lever 25 returns to the state of FIG. 1 and disconnects the input gear 5 from the traveling power transmission system.

As described above, in this embodiment, the second master cylinder 13 of the second hydraulic operating system 33 is operated by the manual lever 17, and the lever switch 27 indicates that the manual lever 17 has been switched. The control valve 24 is actuated in response to this detection signal, and the input gear 5 is connected to the traveling power transmission system via the vacuum cylinder 22. Therefore, compared to the fully automated take-out power intermittent mechanism, The operation mechanism of the master cylinder 13 can be simplified only by the manual lever 17, and the manufacturing cost can be reduced.

Further, since the gear operation system 34 operates after the manual lever 17 is completely switched, it is possible to eliminate the operation of the power take-out mechanism due to carelessness and error when starting the intermittent operation of the take-out power by a switch operation. It is possible to improve the safety of work by eliminating the situation where the work machine suddenly operates.

Further, depending on the working machine, by adjusting the operation amount of the manual lever 17, the power can be transmitted in the half-clutched state, and the rising operation of the working machine can be smoothly performed.

FIG. 4 shows another embodiment of the gear operating system 34. The vacuum cylinder 22 in the previous embodiment is a fluid pressure cylinder 22a operated by pressurized air, and the shift lever 25 is operated by pressurized air. The blower 20a for generating the pressurized air and the air tank 21a for storing the pressurized air, and the fluid pressure cylinder 2 provided in the air passage 23a between the air tank 21a and the fluid pressure cylinder 22a. A shift lever 25 provided on the power take-off mechanism 4 is operated by a fluid pressure cylinder 22a, and the input gear 5 is shifted. The control valve 26 normally shuts off the air passage 23a, communicates the air passage 23a only when the spool 26a is switched by electromagnetic force, and supplies pressurized air to the fluid pressure cylinder 22a. It is supposed to do. Other configurations, operations and effects are similar to those of the previous embodiment.

The control device 28 may be composed of a semiconductor circuit.

[0028]

[Effect of the device]

 As described above, according to the present invention, the master cylinder of the second hydraulic operation system, which connects and disconnects the clutch with a system different from the clutch pedal operation system, is operated by the manual lever, and the manual operation of the lever is changed. By detecting with a switch and receiving the detection signal, the control valve was activated, and the input gear was connected to the traveling power transmission system via the fluid pressure cylinder, which is a comparison with the fully automatic take-out power intermittent mechanism. The operating mechanism of the master cylinder can be simplified only by the manual lever, and the manufacturing cost can be reduced by the reduction of the number of constituent members.

Further, since the gear operation system is activated after the manual lever is completely switched, this is a problem in the conventional mechanism in which the extraction power is intermittently started by the switch operation. By canceling the operation of the power take-out mechanism, it is possible to operate the work machine by the branch power only with the explicit permission of the worker, and eliminate the situation where the work machine operates abruptly without prior safety confirmation. The work safety can be improved.

Further, depending on the working machine, the operation amount of the manual lever is adjusted to transmit the power in a half-clutch state, so that the rising operation of the working machine can be smoothly performed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an overall configuration of a power takeoff device according to an embodiment of the present invention.

FIG. 2 is a schematic explanatory view showing a structure of an input portion of the power take-out mechanism.

FIG. 3 is an electric circuit diagram showing a part of a control device.

FIG. 4 is a configuration diagram showing another embodiment of a gear operation system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine 3 ... Clutch 4 ... Power extraction mechanism 5 ... Input gear 8 ... 1st master cylinder 11 ... Booster 13 ... (2nd) master cylinder 15 ... Switching valve 17 ... Manual lever 20 ... Vacuum pump 22 ... Vacuum cylinder (fluid) Pressure cylinder) 24 ... Control valve 25 ... Shift lever 27 ... Lever switch 28 ... Control device (control means) 32 ... First hydraulic operating system 33 ... Second hydraulic operating system 34 ... Gear operating system

Claims (1)

[Scope of utility model registration request] 1. A power take-off mechanism is provided in a traveling power transmission system after a clutch for connecting and disconnecting engine power to wheels, and a first hydraulic operation system for connecting and disconnecting the clutch in conjunction with a clutch pedal and a manual lever. A power take-off device for a work vehicle, comprising: a second hydraulic operating system for interlockingly operating a clutch in an interlocking manner; and a gear operating system for switching an input gear of a power take-out mechanism, wherein the second hydraulic operating system is , Has a master cylinder that is operated by a manual lever, and the hydraulic oil passage of the master cylinder connects the switching valve to the operating part of the clutch so that the clutch can be engaged and disengaged by both the clutch pedal and the manual lever. The gear operating system consists of a fluid pressure cylinder for switching the input gear switching shift lever, a fluid source, and a working fluid from the fluid source to the fluid pressure cylinder. An electromagnetically operated control valve for controlling supply, a lever switch for detecting that the manual lever has been switched to the clutch disengagement position, and a clutch for operating the manual lever based on a detection signal from the lever switch. And a control means for switching and controlling the control valve so that the input gear is connected to the traveling power transmission system after the power supply is cut off.