JP3209286B2 - Anti-seizure device when starting the engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for preventing seizure of an engine mounted on a construction machine such as a hydraulic shovel or a work vehicle when the engine is started.

[0002]

2. Description of the Related Art FIG. 3 is a partially cutaway rear view of a hydraulic shovel 1 as viewed from the rear. In the drawing, reference numeral 2 denotes an upper revolving superstructure which is a vehicle body of the excavator 1, 3 denotes a lower traveling body, 4 denotes an engine, 5 denotes an oil pan of the engine 4, and 6 denotes an engine lubrication pump. FIG. 4 is a lubricating oil circuit diagram of the engine 4. In the figure, reference numeral 7 denotes a drive source of an engine lubrication pump 6 (hereinafter, referred to as lubrication pump 6), 8 an oil strainer, 9 a relief valve, 10 a check valve, 1
1 is a full oil filter, 12 is a bypass oil filter, 13 is an oil cooler, 14 is a bypass valve, and 15 is a regulator valve.

[0003] The engine 4 mounted on the excavator 1
Is started, the lubrication pump 6 rotates. The lubricating oil in the oil pan 5 is sucked into the lubrication pump 6 via the oil strainer 8. The lubricating oil discharged from the lubrication pump 6 is supplied to the oil main gallery through the check valve 10, the full oil filter 11 or the bypass oil filter 12, the oil cooler 13 or the bypass valve 14. The lubricating oil returns to the oil pan 5 through oil passages branched from the oil main gallery, around lubrication required parts such as crankshaft bearings, and the like.

[0004]

In a conventional hydraulic excavator, an accelerator lever (not shown in FIGS. 3 and 4) for adjusting the rotation of the engine to a high speed and a low speed is moved to a high idle position (medium speed to high speed). When the engine is started at the rotational position, the engine rotates at a medium speed to a high speed before the lubricating oil reaches the lubricating oil circuit of the engine completely. As a result, lubrication of various parts required for lubrication, such as the crankshaft bearing of the engine, was insufficient, and there was a possibility that a seizure accident might occur, resulting in poor maintenance. It is an object of the present invention to provide an anti-seizure device at the time of engine start that can solve the above problems.

[0005]

A construction machine equipped with the anti-seizure device of the present invention outputs an accelerator lever operation signal from an accelerator lever device to a governor of an engine via a controller and a control motor. A hydraulic shovel, wherein as an anti-seizure device at the time of engine start, means for detecting rotation or non-rotation of the engine,
Means for controlling engine rotation to low idle rotation regardless of the position of the accelerator lever until the lubricating oil flows into the lubricating oil circuit after the engine starts. Further, it is displayed that the engine is performing low idle rotation from the start of the engine until the lubricating oil flows to the lubricating oil circuit.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a circuit diagram showing a burn-in prevention device 16 of the present invention. In the figure, 4 'is the engine, 6'
, An engine lubrication pump (hereinafter referred to as a lubrication pump), 17 is a governor, 18 is a governor lever of the governor 17, 19 is an accelerator lever device, 20 is an accelerator lever of an accelerator lever device 19, 21 is an accelerator lever 20
, A reference numeral 22 denotes a lever end, a reference numeral 23 denotes an accelerator lever device mounting plate, a reference numeral 24 denotes a high idle position stopper of the accelerator lever 20, a reference numeral 25 denotes a low idle position stopper,
6 is a potentiometer, 27 is an input lever portion of the potentiometer 26, 28 is a controller, 29 is a pressure switch, 30 is a control motor such as a stepping motor, 31 is a drive lever of the control meter 30, 32 is a display, and 33 is a controller 28 The arrow H indicates the high idle operation direction of the accelerator lever 20, and the arrow L indicates the low idle operation direction.

Next, the structure of the anti-seizure device 16 of the present invention will be described with reference to FIG. The construction machine equipped with the anti-seizure device 16 of the present invention outputs an accelerator lever (20) operation signal from the accelerator lever device 19 to the governor 17 of the engine 4 'via the controller 28 and the control motor 30. The hydraulic excavator has a pressure switch 29 for detecting the pump pressure of the lubricating oil pump 6 'as means for detecting rotation or non-rotation of the engine 4', for example, as a seizure prevention device (16) for the engine 4 '.
After the engine 4 'is started, the lubricating oil flows around a lubricating oil circuit (this lubricating oil circuit is similar to the lubricating oil circuit of the prior art engine 4 shown in FIG. 4). Until now, means for controlling the engine (4 ') rotation to the low idle rotation regardless of the position of the accelerator lever 20 (the operation position such as the high idle position or the low idle position) is provided. Further, the display 32 indicates that the engine 4 ′ is performing low idle rotation from the start of the engine 4 ′ to the time when lubricating oil is supplied to the lubricating oil circuit.

Next, the operation of the anti-seizure device 16 of the present invention will be described. First, the accelerator lever 20 is set to the low idle position, and the engine 4 'is started. The accelerator lever low idle position operation signal from the potentiometer 26 is input to the controller 28. Controller 28
Then, the determination is made based on the accelerator lever low idle position operation signal, and an engine low idle rotation command signal is output to the control meter 30. Since the control motor 30 rotates to adjust the governor 17, the engine 4 'keeps the low idle rotation. At the same time controller 2
8, a low idle rotation display command signal is output to the display 32, so that the display 32 indicates that the engine 4 'is performing low idle rotation. Since the rotation of the engine 4 'is low at the time of the low idle rotation, lubrication of each part required for lubrication of the engine 4' is sufficient.
There is no seizure accident.

Next, a case where the engine 4 'is started with the accelerator lever 20 in the high idle position will be described. FIG. 2 is a chart showing a case where the engine 4 'is started with the accelerator lever 20 in the high idle position. In FIG. 2, high is a phrase in which the high idle position is omitted, and low is a phrase in which the low high idle position is omitted. The time t1 is a time previously set in the timer function 33 of the controller 28, but is a time required until the pump pressure of the lubrication pump 6 'is generated and the lubricating oil flows to the lubricating oil circuit of the engine 4'. It is. Time t0 indicates an elapsed time range from the start of the engine (4 ′) to the end of the time t1. When the engine 4 'is started with the accelerator lever 20 in the high idle position as shown in FIG. 2, the pump pressure of the lubrication pump 6' does not rise to a predetermined pressure at that time. Based on the pressure signal from the pressure switch 29 and the accelerator lever high idle position operation signal from the potentiometer 26, the controller 2
In step 8, a low idle rotation command signal is output to the control meter 30 even if the accelerator lever 20 is operated to the high idle position. Since the control meter 30 operates at the low idle rotation position (not shown),
The governor 17 is automatically adjusted, and the engine 4 'performs low idle rotation. When the pump pressure of the lubrication pump 6 ′ rises to a predetermined pressure, a rising pressure signal is input to the controller 28 through the pressure switch 29. In the controller 28, the timer function 33 is activated from that point on, and outputs a high idle rotation command signal to the control motor 30 with a delay of time t1. Control meter 30
Operates in the high idle rotation position, the governor 17 is automatically adjusted, and the engine 4 'performs high idle rotation. That is, from the time when the engine 4 'is started,
If the accelerator lever 20 is operated to the high idle position within the elapsed time range of the time t0 until the lubricating oil completely flows into the lubricating oil circuit of the engine 4 ', the judgment of the engine 4 is performed by the controller 28. 'Performs low idle rotation. Therefore, the anti-seizure device 16 of the present invention can prevent the occurrence of an anti-seizure accident when starting the engine. In this embodiment, a pressure switch is used as the engine rotation detecting means. However, instead of the pressure switch, means for providing a rotation sensor to the engine may be employed.

During a time t0 from when the engine 4 'is started to when the lubricating oil flows to the lubricating oil circuit, the controller 28 outputs a display command signal to the display 32. As a result, the display 32 indicates that the engine 4 'is rotating at low idle.
The driver can easily recognize the display and respond accordingly.

[0011]

In the prior art hydraulic excavator, when the engine is started with the accelerator lever in the high idle position, the engine rotates at a high speed before the lubricating oil completely flows into the lubricating oil circuit of the engine. As a result, the lubrication of each part of the engine requiring lubrication was inadequate, and there was a risk of occurrence of seizure accidents, resulting in poor maintenance. However, in the anti-seizure device of the present invention, the means for detecting the rotation and non-rotation of the engine and the rotation of the engine from low to high regardless of the position of the accelerator lever from the start of the engine until the lubricating oil flows to the lubricating oil circuit. And means for controlling the idle rotation. As a result, even if the accelerator lever is operated to the high idle position within the range of elapsed time from when the engine is started to when the lubricating oil completely flows into the lubricating oil circuit of the engine, it is determined by the controller's determination process. The engine performs low idle rotation. Therefore, occurrence of a seizure accident at the time of starting the engine can be prevented. Further, a display command signal is output from the controller to the display from the start of the engine until the lubricating oil flows to the lubricating oil circuit. As a result, the display indicates that the engine is rotating at low idle, so that the driver can easily recognize the display and respond accordingly.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram showing an image sticking prevention device of the present invention.

FIG. 2 is a chart showing a case where an engine is started with an accelerator lever in a high idle position in FIG. 1;

FIG. 3 is a partially cutaway rear view of the excavator as viewed from the rear.

FIG. 4 is a lubricating oil circuit diagram of the engine.

[Explanation of symbols]

 4,4 'engine 6,6' engine lubrication pump 16 anti-seizure device 17 governor 19 accelerator lever device 20 accelerator lever 28 controller 29 pressure switch 30 control motor 32 display 33 timer function

Claims (2)

(57) [Claims] An engine having a lubricating oil circuit is mounted on a vehicle body, and an accelerator lever device for adjusting the rotation of the engine at high speed and low speed is provided. An accelerator lever operation signal from the accelerator lever device is transmitted to a controller and a controller. A construction machine which outputs to a governor of an engine via a control motor, wherein a means for detecting rotation and non-rotation of the engine, and the lubricating oil is supplied to a lubricating oil circuit after the engine is started. Means for controlling the engine speed to low idle speed regardless of the position of the accelerator lever until turning. 2. The anti-seizure device at the time of starting the engine according to claim 1, wherein the engine performs a low idle rotation until the lubricating oil flows to a lubricating oil circuit after the engine is started. Is displayed on the display.