JPH0538362U - Engine starter in Backhoe - Google Patents

Abstract

(57) [Summary] [Purpose] The engine was designed to improve the starting performance of the engine on the backhoe. [Structure] A cutoff valve is provided between the hydraulic pump for the hydraulic pilot driven by the engine and the electromagnetic proportional control valve, and the cutoff valve is used only when the starter switch for starting the engine is set to the start position. An engine starter for a backhoe, which is capable of passing a current freely, and at a start position of which a cutoff valve is turned on to return the hydraulic oil discharged from the hydraulic pump to the hydraulic oil tank side.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an engine starter for a backhoe that performs excavation work.

[0002]

[Prior Art]

 Conventionally, the backhoe engine starter operates the hydraulic proportional control valve by a hydraulic pilot while operating the hydraulic switching valve for the hydraulic actuator on the excavation side.In this case, the pilot pressure is cut off. It was configured to start the engine with the valve always generated.

[0003]

[Problems to be solved by the device]

 However, in the above embodiment, only the relief set pressure generated on the cut-off valve side is generated as hydraulic resistance, and the startability is particularly low when the engine is started in a cold place such as a cold region. It was bad.

[0004]

[Means for Solving the Problems]

 According to the present invention, in the backhoe configured to operate the solenoid proportional control valve with the hand operation lever, and to operate the hydraulic actuator drive hydraulic switching valve of the working section by the hydraulic pilot of the solenoid proportional control valve, A cut-off valve is provided between the hydraulic pump for hydraulic pilot driven by the engine and the electromagnetic proportional control valve, and moreover, current is supplied to the cut-off valve only when the starter switch for engine start is set to the start position. At the same time, at the start position, the cut-off valve is turned on so that the hydraulic oil discharged from the hydraulic pump is returned to the hydraulic oil tank side. It

Further, an emergency stop switch for operating a fuel stop solenoid is connected to the engine starter switch, and a relay that operates in conjunction with ON operation of the emergency stop switch is connected to the starter switch and the starter motor. It is also characterized in that the starter motor is placed in an inoperative state when the emergency stop switch is turned on.

[0006]

【Example】

 An embodiment of the present invention will be specifically described with reference to the drawings. 1 is a main body of a backhoe, which is provided with a crawler traveling device 2 at a lower portion thereof, and a swivel frame 3 is mounted on an upper portion of the crawler traveling device 2. It can be freely turned to the left and right. Reference numeral 4 denotes a working unit that is continuously provided in front of the swing frame 3, and allows the main boom 5, the offset arm 6-1, the intermediate arm 6-2, the bucket arm 6-3, and the bucket 7 to be vertically rotatable. In addition, hydraulic actuators 8, 9-1, 9-2, 10 are provided between them. Reference numeral 11 denotes a turning hydraulic motor for turning the turning frame 3. The operation control of these hydraulic actuators 8, 9-1, 9-2, 10 and the turning hydraulic motor 11 is carried out by operating the hand operation levers 13, 14 provided in the operating section 12 to operate pilot-operated hydraulic control valves. Done through. Further, the operation unit 12 is provided with the above-mentioned hand operation levers 13 and 14 above the left and right operation panels 15 and 16. 17a and 17b are left and right traveling levers provided in front of the seat 18.

Further, in FIG. 3, reference numeral 19 denotes an engine, which directly connects the main operation hydraulic pumps 20-1, 20-2, 20-3 and the hydraulic pilot hydraulic pump 21. 22 is a discharge pipe for supplying high-pressure operating oil. Reference numeral 23 is a suction pipe, and 24 is a hydraulic oil tank.

Reference numeral 25 denotes a hydraulic pressure switching valve of the main boom hydraulic actuator 8, which is provided with an electromagnetic proportional control valve 26. Reference numeral 27 denotes a hydraulic pressure switching valve of the hydraulic actuator 9-1 for the offset arm, which is provided with an electromagnetic proportional control valve 28. Reference numeral 29 is a hydraulic switching valve of the arm hydraulic actuator 9-2, which is provided with an electromagnetic proportional control valve 30. Reference numeral 31 is a hydraulic pressure switching valve of the bucket hydraulic actuator 10, which is provided with an electromagnetic proportional control valve 32. 33 is a left-hand running hydraulic motor, which is connected to the hydraulic switching valve 34. Reference numeral 35 denotes a right-side traveling hydraulic motor, which is connected to the hydraulic pressure switching valve 36. A hydraulic switching valve 37 is connected to the swing hydraulic motor 11, and an electromagnetic proportional control valve 38 is provided. 39 is a hydraulic cylinder for raising and lowering the blade, which is connected to the hydraulic switching valve 40.

Reference numeral 41 is a cut-off valve connected between the electromagnetic proportional control valves 26, 28, 30, 32, 38 and the hydraulic pilot hydraulic pump 21 and is connected to a starter switch 42 to turn ON. , Can be turned off.

Further, FIG. 4 is an electric circuit diagram showing a connection state of the starter switch 42 and the cutoff valve 41, and FIG. 5 shows a connection table of the starter switch 42, in which 43 is a battery 44. A contact point position connected with the, 45 is an AC contact point position for connecting the power supply to the ON state, 46 is a B contact point position for connecting the heater and the relay 47 for heating the engine 19, 48 is the starter motor and the cutoff valve 41 At the C contact position to be connected, the cut-off valve 41 is turned on at the time of start to guide the high-pressure hydraulic oil discharged from the hydraulic pilot hydraulic pump 21 to the hydraulic oil tank 24 side.

Reference numeral 49 denotes a solenoid valve provided in the cutoff valve 41, which normally makes the discharge pipe 50 of the hydraulic pump 21 for the hydraulic pilot and the respective electromagnetic proportional control valves 26, 28, 30, 32, 38 in a communicating state. ..

Reference numeral 51 is a relief valve, and 52 is a hand operation changeover switch.

The embodiment of the present invention is configured as described above, and when the starter switch 42 is operated to the start position, the solenoid valve 49 of the cutoff valve 41 is actuated, and the cutoff valve 41 is turned on. .. Then, the high pressure hydraulic oil in the discharge pipe 50 on the hydraulic pump hydraulic pump 21 side is returned to the hydraulic oil tank 24 side. Therefore, when the starter switch 42 is started, the high pressure hydraulic oil discharged from the hydraulic pilot hydraulic pump 21 can be returned to the hydraulic oil tank 24 side, so that there is no hydraulic resistance and the engine startability is good.

FIG. 6 shows the relationship between the starter switch, the emergency stop switch, and the fuel stop solenoid. In the figure, 60 is a starter switch and 61 is a battery. 62 is an emergency stop switch that stops the engine fuel and stops the engine, and 63 is a starter motor, which is composed of a magnetic switch 63-1 and a motor 63-2. A fuel stop solenoid 64 is composed of a holding side 64-1 and a suction side 64-2. Reference numeral 65 is a relay connected to the holding side coil 64-1 of the fuel stop solenoid 64, 66 is a relay connected to the suction side coil 64-2, and a timer 67 is interposed. 68 is a relay connected to the starter motor 63 side circuit, 69 is a relay connected to the microcomputer side power source 70, and 71 is a relay provided on the air heater 72 side.

Therefore, in the above embodiment, the relay 68 operates and the starter motor 63 does not rotate even if the starter switch 60 is turned to the start position while the emergency stop switch 62 for stopping the engine is being pressed. Is. Further, the suction side coil 64-2 of the fuel stop solenoid 64 does not operate due to the operation of the relay 68. As a result, even if the starter switch 60 is turned to the start position while the emergency stop switch 62 is being pressed, the starter motor 63 and the fuel stop solenoid 64 do not operate, so the battery will run out even if the driver operates it by mistake. It surely prevents it.

Further, in the above embodiment, since the timer 67 is provided between the starter switch 60 and the relay 66 of the suction side coil 64-2 of the fuel stop solenoid 64, the fuel stop solenoid 64 is provided. The electric current to the relay 66 that drives the suction side coil 64-2 is automatically cut when the starter switch 60 is at the start position for a few seconds.

Therefore, when the engine is started, the current to the suction side coil 64-2 of the fuel stop solenoid 64 is cut within a few seconds, and only the starter motor and the air heater are energized, so that the engine startability is good.

FIG. 7 shows an engine start control circuit, which controls the engine start by detecting the temperature at the engine start.

In the figure, 70-1 is a starter switch, which is connected to the battery 71-1. 72-1 is a temperature sensor connected to the control circuit 73. 74 is an air heater such as a glow plug that heats the inside of the engine, and a relay 75 is interposed between the starter switch 70 and the air heater. The relay 75 is connected to the control circuit 73. Further, reference numeral 76 is a starter motor which is provided with a relay 77, and the relay 77 is connected to the control circuit 73.

Therefore, in the above embodiment, the temperature on the engine side is detected by the temperature sensor 72-1 and input to the control circuit 73. When the engine temperature is low and it is difficult to start the engine, the controller turns on the relay 75 on the air heater side and turns off the relay 77 on the starter motor side. Therefore, when the starter switch 70-1 is turned to the starting position, the electric current is passed through the control circuit 73 to the air heater 74 to preheat the engine. When the preheating of the engine is completed, the control circuit 73 energizes the starter motor 76 to start the engine. According to the above embodiment, when the driver starts the engine, it is not necessary to preheat the engine, and therefore the starting operation is simple.

Further, in the past, since the engine was directly started even when preheating was required, the starter motor was rotated many times and the starter motor and the battery were often damaged. For example, the life of the starter motor and battery will be extended.

Further, since the number of contacts of the starter switch is reduced, the starter switch body can be downsized.

[0023]

[Effect of the device]

 According to the present invention, when the starter switch is operated to the start position, the cutoff valve operates to return the hydraulic oil in the discharge pipe of the hydraulic pilot hydraulic pump side to the hydraulic oil tank side. The startability is good.

Further, according to the present invention, an emergency switch for operating a fuel stop solenoid is connected to the starter switch for starting the engine, and a relay connected to the emergency switch is connected between the starter switch and the starter motor. It is designed to prevent the starter motor from operating even when the starter switch is turned to the start position by the relay.Therefore, while the emergency stop switch that stops the engine is being pressed, turn the starter switch to the start position. The relay does not start and the starter motor does not start.Therefore, even if the driver mistakenly operates the starter switch while the emergency stop switch is being pressed, the engine will not start, so it is possible to reliably prevent the battery from rising. is there.

[Brief description of drawings]

FIG. 1 is an overall side view of a backhoe equipped with the present invention.

FIG. 2 is a schematic plan view of the same.

FIG. 3 is a hydraulic circuit diagram of a main part of the present invention.

FIG. 4 is an electric circuit diagram of the same.

FIG. 5 is a connection table of starter switches.

FIG. 6 is an electric circuit diagram showing a second embodiment of the present invention.

FIG. 7 is an electric circuit diagram showing the third embodiment.

[Explanation of symbols]

 4 Working unit 13 Hand control lever 14 Hand control lever 21 Hydraulic pump 25 Hydraulic switching valve 26 Electromagnetic proportional control valve 27 Control valve 28 Electromagnetic proportional control valve 29 Hydraulic switching valve 30 Electromagnetic proportional control valve 31 Hydraulic switching valve 32 Electromagnetic type Proportional control valve 41 Cut-off valve 42 Starter switch 60 Starter switch 62 Emergency stop switch 63 Starter motor

Claims (2)

[Scope of utility model registration request] 1. A backhoe configured to operate a solenoid proportional control valve with a hand operation lever and to operate a hydraulic actuator driving hydraulic switching valve of a working portion by a hydraulic pilot of the solenoid proportional control valve. A cut-off valve is provided between the hydraulic pilot-driven hydraulic pump driven by the engine and the electromagnetic proportional control valve, and moreover, current is supplied to the cut-off valve only when the engine starter switch is set to the start position. An engine starter for a backhoe, which is electrically energizable and has a cutoff valve turned on at the start position to return the hydraulic oil discharged from the hydraulic pump to the hydraulic oil tank side. 2. An engine start starter switch is connected to an emergency stop switch for operating a fuel stop solenoid, and a relay that operates in conjunction with ON operation of the emergency stop switch is provided between the starter switch and the starter motor. An engine starter for a backhoe, characterized in that the starter motor is in a non-operating state when an emergency stop switch is turned on.