JPH0314419Y2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field of the Invention The present invention relates to an engine power extraction device suitable for transmitting the driving force of a vehicle engine to a drive device such as a hydraulic power unit via an electromagnetic clutch.

(b) Prior art and problems When driving a drive device such as a hydraulic power unit in a vehicle such as a garbage truck or concrete mixer truck, the driving force of the engine is extracted through an electromagnetic clutch, and the extracted driving force is used to drive a drive device such as a hydraulic power unit. It has been attempted to drive a drive device. For example, in a concrete mixer truck, the mixer drum is hydraulically driven, and the hydraulic pump constituting the hydraulic power unit is configured to be driven using part of the output of the vehicle engine.

However, if the power take-off device was activated when the engine was started, the hydraulic power unit would be driven even when it was not necessary to drive the hydraulic power unit, which could pose a risk to safety.

Therefore, conventionally, as described in Publication No. 59-27296, the engine start circuit and
A system has been proposed that is linked to a PTO (power take-off) switch so that the engine cannot be started when the PTO switch is on.

However, in conventional power take-off devices, the electromagnetic clutch was configured to connect and disconnect according to commands from the PTO switch during driving, so the PTO
If you drive without turning off the switch, there is a possibility that the drive system will start operating.

(c) Purpose of the invention The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to provide an engine power take-off device that can prevent the drive device from being in the driving state when the vehicle is running. Our goal is to provide the following.

(d) Structure of the invention In order to achieve the above object, the present invention provides a vehicle speed sensor for detecting vehicle speed and a vehicle speed sensor in an engine power extraction device that transmits the driving force of the engine to the drive device via an electromagnetic clutch. When the vehicle speed is below the set vehicle speed by monitoring the detection output of In this case, the engine power extraction device includes a control device that disables the command from the command switch, forcibly opens the electromagnetic clutch, cuts off the driving force, and maintains this state.

(e) Embodiments of the invention Hereinafter, preferred embodiments of the invention will be described based on the drawings.

FIG. 1 shows the configuration of a preferred embodiment of the present invention. In the figure, a vehicle speed sensor 10 is placed between a speedometer cable that connects a transmission 14 and a speedometer 12, and detects the vehicle speed from the number of rotations of the cable. and is output to the holding circuit 20 of the control device 18. The controller 16 outputs an ON signal to the holding circuit 20 when the vehicle speed is below the set vehicle speed, and outputs an OFF signal to the holding circuit 20 when the vehicle speed exceeds the set speed. Further, the holding circuit 20 is supplied with an output signal from a seesaw switch 24 as a command switch for commanding the operation of the electromagnetic clutch 22, and when the seesaw switch 24 is turned on, an on signal is output from the controller 16. It is configured to output a drive signal to the relay 26 under the condition that Note that a pilot lamp 28 is connected to the output of the holding circuit 20. Further, the controller 16 and the holding circuit 20 are operated by an ignition switch.
Power is supplied from the battery via the ACC relay 30, and the electromagnetic clutch 22 is supplied with power from the battery.
6. Power is supplied from the battery via the ACC relay 30.

Relay 26 is a normally open type relay, and is configured such that contact 26B closes when coil 26A is excited. When the contact 26B of the relay 26 is closed, the electromagnetic clutch 22 is connected to transmit the driving force, and when the contact 26B is opened, the electromagnetic clutch 22 is forcibly opened to cut off the driving force. ing. Note that a diode 32 for bypassing the back electromotive force is connected to both ends of the electromagnetic clutch 22.

In the above configuration, when the vehicle speed sensor 10 detects that the vehicle speed is below the set vehicle speed, the controller 16 outputs an on signal to the holding circuit 20, and the holding circuit 20 is turned on. At this time, when the seesaw switch 24 is turned on, a drive signal is output from the holding circuit 20, the pilot lamp 28 lights up, and the relay 26
The coil 26A is energized and the contact 26B is closed.
As a result, electric power from the battery is supplied to the electromagnetic clutch 22 via the ACC relay 30 and the relay 26, and the electromagnetic clutch 22 is connected to transmit driving force. When the electromagnetic clutch 22 is connected and transmits the driving force, the driving force of the engine is transmitted to the hydraulic pump (not shown) via the electromagnetic clutch 22, and the hydraulic pump is operated by the engine's driving force, and the hydraulic cylinder is also operated. It becomes possible.

On the other hand, when the vehicle speed sensor 10 detects that the vehicle speed exceeds the set vehicle speed, an off signal is output from the controller 16 to the holding circuit 20.
The holding circuit 20 maintains the off state. Therefore, the drive signal is no longer output from the holding circuit 20, the coil 26A becomes de-energized, the contact 26B opens, and the electromagnetic clutch 22 is forcibly opened to cut off the drive force. This prevents the engine's driving force from being transmitted to the hydraulic pump.

Furthermore, when the vehicle speed exceeds the set vehicle speed, the holding circuit 20 maintains the OFF state, so even if the seesaw switch 24 is turned on at this time, the turning-on operation of the seesaw switch 24 is invalidated, and the seesaw switch 2
Regardless of the on/off operation of 4, the electromagnetic clutch 22
is forcibly opened and the driving force is cut off. Therefore, even if the garbage truck forgets to turn off the seesaw switch 24 while the garbage truck is running, the hydraulic pump can be prevented from operating. Furthermore, the electromagnetic clutch 22
Since it is possible to prevent the hydraulic pump from operating all the time, it is possible to prevent a decrease in life and also to prevent deterioration of the hydraulic fluid.

(F) Effect of the invention As explained above, according to the invention, when the vehicle speed exceeds the set vehicle speed, the command from the command switch is invalidated and the electromagnetic clutch is forcibly opened to cut off the driving force. Therefore, it is possible to prevent the drive device from going into the driving state during driving due to forgetting to turn off the command switch, etc., and it is possible to obtain an excellent effect that it can contribute to improving safety.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention. 10... Vehicle speed sensor, 12... Speed meter, 20... Holding circuit, 22... Electromagnetic clutch,
24...Seesoswitch, 26...Relay.

Claims (1)

[Scope of utility model registration request] In the engine power extraction device that transmits the driving force of the engine to the drive device via the electromagnetic clutch, there is a vehicle speed sensor that detects the vehicle speed, and the detection output of the vehicle speed sensor is monitored and when the vehicle speed is less than the set vehicle speed, the electromagnetic clutch is The electromagnetic clutch is connected in response to the ON command of the command switch that commands disconnection and connection, and the driving force is transmitted. When the vehicle speed exceeds the set vehicle speed, the command of the command switch is invalidated and the electromagnetic clutch is forcibly opened. What is claimed is: 1. A power extraction device for an engine, comprising: a control device that cuts off driving force and maintains this state.