JPS6215333Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a noise control device for civil engineering and cargo handling machines.

[Prior art]

It is known that the noise emitted by civil engineering and material handling machines such as shovels and cranes is approximately proportional to the number of revolutions of their engines. In order to suppress this, the maximum rotational speed of the engine can be regulated and the civil engineering cargo handling work can be carried out within this maximum rotational speed.

For this reason, conventionally, the noise emitted by the civil engineering cargo handling machine is known in advance and the maximum engine speed is set so that the noise is below a permissible level.

[Problem that the invention attempts to solve]

However, simply setting the maximum engine speed in this way can suppress the noise emitted by the civil engineering and cargo handling equipment itself to below a certain level, but depending on the environment around the work site, the actual noise level may vary. sometimes exceeded the permissible level. In other words, when the work site is in the suburbs, the noise emitted by the civil engineering and material handling machines is spread over a wide area, so the noise around the work site is almost never louder than the noise emitted by the civil engineering and material handling machines themselves. If the work site is in an urban area, the noise emitted by the civil engineering and cargo handling equipment will be reflected by buildings and other valleys, causing the noise around the work site to exceed permissible levels. Furthermore, if the maximum engine speed is set sufficiently low, the maximum noise level emitted by the civil engineering cargo handling machine itself can be lowered, and the actual noise including reflected sound can be reduced.
If the maximum rotational speed of the engine is set low in this way, the output of the engine will be suppressed to a low level, and the working capacity of the civil engineering cargo handling machine will be reduced.

This idea was devised based on these circumstances, and its purpose is to ensure that the noise around the work site is kept below the permissible level in any work environment, and that it also helps civil engineering To provide a noise control device for a civil engineering cargo handling machine capable of increasing the working capacity of the cargo handling machine to the maximum within a range where the noise does not exceed an allowable level.

[Means to solve problems]

That is, this invention includes a noise detector that detects noise during civil engineering cargo handling work, a noise level setting device, and a noise level setting device that compares the noise value detected by the noise detector with the noise level set in the setting device. a comparator that outputs an engine control signal when a noise value exceeds a set noise level; a cylinder control valve that is operated by the engine control signal from the comparator;
It has an engaging part that removably engages with the accelerator lever of the engine, and when the detected noise value exceeds the set noise level, it is operated by the operation of the control valve and engages with the accelerator lever. The accelerator rotates the engine back in the direction of lowering the rotational speed, and when the detected noise value becomes lower than the set noise level, the control valve moves in the opposite direction to release the engagement with the accelerator lever. The lever is characterized by being equipped with a lever return rotation cylinder.

[Effect]

In other words, with this invention, when the detected noise value exceeds the set noise level, the accelerator lever of the engine is returned and rotated using the accelerator lever return rotation cylinder to automatically lower the engine speed and the detected noise value is set. When the noise level becomes lower than the noise level, the accelerator lever is operated in the direction of increasing the engine speed again by operating the accelerator lever return rotation cylinder in the opposite direction to release the engagement with the accelerator lever. Rather than setting the maximum engine speed in advance as in the past, this idea detects the noise actually occurring and detects when the detected noise value exceeds the set noise level. Since the engine speed is lowered during the operation, the noise around the work site can be reliably kept below the permissible level in any work environment, and the cylinder for rotating the accelerator lever is , which operates when the detected noise value exceeds the set noise level and returns and rotates the accelerator lever,
When the detected noise value is lower than the set noise level, it will not operate, so you can arbitrarily operate the accelerator lever to increase the engine speed until the detected noise value exceeds the set noise level. It is possible to increase the working capacity to the maximum level without exceeding the permissible level of noise. Moreover, in this invention, when the detected noise value exceeds the set noise level while operating the accelerator lever in the direction of increasing the engine speed, the accelerator lever return rotation cylinder operates to return the accelerator lever. Since the cylinder tries to rotate the engine, the return rotational force generated by the cylinder acts as a resistance to the operation of the accelerator lever, and the operator may increase the engine speed even further without noticing that the noise has become louder. Furthermore, since the accelerator lever return rotation cylinder is not engaged with the accelerator lever when the detected noise value is lower than the set noise level, until the detected noise value exceeds the set noise level, The accelerator lever can be easily operated without being subjected to resistance from the cylinder.

〔Example〕

An embodiment of this invention will be described below based on the drawings.

In the figure, 1 is the body of the shovel. A pair of frames 2, 2 are provided on the left and right sides of the vehicle body 1, and crawlers 3, 3 are wound around these frames 2, 2, respectively. A swivel base 4 is placed on the vehicle body 1, and the swivel base 4 is provided with a driver's seat 5 and an engine compartment 6. Note that a diesel engine 7, for example, is provided within the engine room 6. A boom 8 is pivotally supported on the swivel base 4 so that it can be raised and lowered, and an arm 10 is rotatably attached to the tip of the boom 8 via a pin 9. Also arm 10
A bucket 13 is rotatably supported at the tip of the bucket via a pin 11 and a link 12. The boom 8, arm 10, and bucket 13 are operated by a boom cylinder 14, an arm cylinder 15, and a bucket cylinder 16, each of which is a hydraulic cylinder.

A noise detector 17 is provided in the engine room 6, and a noise level setting device 18 is provided in the driver's seat 5. The detector 17 is provided to detect noise emitted by the engine 7 as well as external noise,
The setting device 18 can be set to a predetermined noise level depending on the surrounding environment of the work site and the work time period. The detector 17 and setter 18 are connected to comparators 19 and 20, respectively. In addition,
21 is an amplifier, and 22 is an attenuator.

One comparator 19 compares the noise value detected by the detector 17 with a damped noise set value obtained by attenuating the noise set value set by the setting device 18 to a predetermined level by the attenuator 22. When the noise value becomes larger than the attenuation noise setting value, the comparator 19 outputs an alarm signal. The comparator 19 is connected to, for example, a warning lamp 23 disposed inside the driver's seat 5, so that the warning lamp 23 can be turned on by the above-mentioned warning signal.

The other comparator 20 compares the noise value with the noise setting value, and is configured so that when the noise value becomes larger than the noise setting value, a predetermined control signal is output from the comparator 20. It's getting old. The control signal from the comparator 20 is then transmitted to the engine control mechanism 24. This control mechanism 24 includes a cylinder control servo valve 25, an air tank 26, and a pneumatic cylinder 27 for returning and rotating the accelerator lever.
The comparator 20 is connected to the servo valve 25. Servo valve 25 is comparator 2
is operated in response to a control signal of 0, and
The port t and the air tank 26 are connected by an air pipe 28. This air tank 2
Compressed air having a predetermined pressure is always stored in the chamber 6 by a compressor (not shown).
Port c of the servo valve 25 and the pneumatic cylinder 27 are connected by an air pipe 29. Note that port a of the servo valve 25 is open to the atmosphere. The pneumatic cylinder 27 is a single-acting cylinder with a return spring, and its rod 27a can be engaged with and detached from an accelerator lever 30 disposed within the driver's seat 5. That is, an engaging portion 27b that can fit into the accelerator lever 30 is formed at the tip of the rod 27a.
When the lever 7a is extended, the engaging portion 27b engages with the accelerator lever 30 to rotate the accelerator lever 30 in the α direction shown in FIG. Note that a spring plate 3 is attached to the base of the accelerator lever 30 as shown in FIG.
1, and this accelerator lever 30 can be fixed at any position by the frictional force of the spring plate 31. This accelerator lever 30 is connected to a speed control lever 32 that operates the speed control section of the engine 7, and this speed control lever 32 is connected to the accelerator lever 30.
It is designed to rotate in conjunction with the That is, when the accelerator lever 30 is rotated in the α direction, the maximum rotational speed of the engine 7 decreases via the speed control lever 32, and conversely, when the accelerator lever 30 is rotated in the β direction, the maximum rotation speed of the engine 7 decreases. The maximum rotation speed of the engine is increasing. Note that 33 is a stopper that restricts rotation of the speed control lever 32.

Next, the operation of this noise control device will be explained.

First, before carrying out civil engineering cargo handling work, the set value of the noise level setting device 18 disposed in the driver's seat 5 is set to an allowable noise level according to the surrounding environment (work place) and work time. After this, accelerator lever 3
0 in the β direction to increase the rotational speed of the engine 7, that is, the output of the engine 7, and perform the above work. During this work, the noise detector 17 installed inside the engine cover 6 is detecting external noise as well as the noise of the engine 7, and the detected noise value detected by the detector 17 is input to the comparators 19 and 20. be done. Further, among these comparators 19 and 20, one comparator 19 is input with an attenuated noise level value obtained by attenuating the set noise level value set by the setting device 18 by the attenuator 22, and the other The set noise level value is input to the comparator 20 as it is. One comparator 19 compares the detected noise value with the attenuated noise level value, and when the detected noise value becomes larger than the attenuated noise level, an alarm signal is output from the comparator 19 and the alarm lamp is turned on. 23 to warn the operator. The other comparator 20 compares the detected noise value with the set noise level value, and when the detected noise value becomes larger than the set noise level, the comparator 20 outputs an engine control signal. This control signal is transmitted to the servo valve 25 of the engine control mechanism 24 to operate the servo valve 25, and via the servo valve 25, the air tank 2
6 is fed into the pneumatic cylinder 27 for returning and rotating the accelerator lever, and this pneumatic cylinder 27 is extended. When the cylinder 27 is extended, the rod 27a engages and presses the accelerator lever 30 through an engaging portion 27b formed at its tip, thereby rotating the accelerator lever 30 in the α direction. . When the accelerator lever 30 is rotated in the α direction, the speed control lever 32 of the engine 7 is rotated in a predetermined direction to lower the rotational speed of the engine 7, and the noise generated from the engine 7 is reduced.

In this way, when the noise of the engine 7 is reduced and the external noise is also reduced, and the noise value detected by the detector 17 becomes lower than the set noise level, the comparator 20 The output of the engine control signal stops and the servo valve 25
is operated in the opposite direction by the force of the return spring, thereby stopping the supply of compressed air from the air tank 26 to the air cylinder 27, and conversely, the compressed air sent into this pneumatic cylinder 27 is transferred to port a of the servo valve 25. The pneumatic cylinder 27 for returning the accelerator lever is contracted by the return force of the spring, and the rod 27a is released into the atmosphere through the accelerator lever 3.
0 and move back. When the cylinder 27 disengages from the accelerator lever 30, the accelerator lever 30 can again be rotated in the β direction, that is, in the direction of increasing the rotation speed of the engine 7. It is also possible to increase the output of the engine 7 by raising the value.

In other words, this noise control device does not set the maximum engine speed in advance as in the past, but instead detects noise using the noise detector 17 and automatically adjusts the speed when the detected noise value exceeds the set noise level. The number of revolutions of the engine 7 is lowered to reduce the noise generated by the civil engineering cargo handling machine.
By detecting the noise that is actually occurring and controlling the rotational speed of the engine 7 in this way, it is possible to reliably suppress the noise around the work site to below an allowable level in any work environment. In other words,
When the work site is in the suburbs, the noise emitted by the civil engineering and material handling machines is spread over a wide area, so the noise around the work site is almost never louder than the noise emitted by the civil engineering and material handling machines themselves. When the site is in an urban area, the noise emitted by civil engineering equipment is reflected by the valleys of buildings, etc.
Although the noise around the work site is louder than the noise emitted by the civil engineering and cargo handling equipment itself, the above noise control device detects the actual noise being generated and automatically controls the noise level when the detected noise value exceeds the set noise level. The number of revolutions of the engine 7 is lowered to reduce the noise generated by the civil engineering and cargo handling equipment, so whether you are working in an urban area or in the suburbs, the noise around the work site can be reduced depending on the environment and working hours. It is possible to reliably suppress the noise level to below the permissible noise level.
Moreover, in the above-mentioned noise control device, control of the engine 7 is canceled when the detected noise value becomes lower than the set noise level, so after the control of the engine 7 is canceled, the rotation speed of the engine 7 is restarted. If the rotation speed of the engine 7 is increased too much and the noise exceeds the set noise level, the engine control mechanism 24 will operate again to lower the rotation speed of the engine 7. , it is possible to increase the working capacity of the civil engineering material handling machine to the maximum extent within the range where the noise does not exceed the permissible level. Furthermore, in the above embodiment,
Since the warning lamp 23 is first turned on before the engine control mechanism 24 operates, the operator is notified that the noise level is close to the permissible level, and the engine 7 It is also possible to stop the rotation speed from increasing.

Further, in the above-mentioned noise control device, when the detected noise value exceeds the set noise level while operating the accelerator lever 30 in the direction (β direction) of increasing the rotation speed of the engine 7, the air pressure for returning the accelerator lever is Since the cylinder 27 operates to return and rotate the accelerator lever 30, the return rotational force generated by the cylinder 27 becomes a resistance to the operation of the accelerator lever 30, and therefore, the operator may notice that the noise increases. It is possible to prevent the rotation speed of the engine 7 from increasing further without realizing it, and the pneumatic cylinder 27 for returning and rotating the accelerator lever engages with the accelerator lever 30 when the detected noise value is lower than the set noise level. Since they do not match, the accelerator lever 30 can be easily operated without being subjected to resistance from the cylinder 27 until the detected noise value exceeds the set noise level.

Note that this invention is not limited to the above embodiment. For example, a noise detector is not necessarily installed in the engine room, but may be installed outside, such as on the body of an excavator. It is possible to effectively detect the noise around the work site and more accurately detect the noise around the work site.

[Effect of idea]

Rather than setting the maximum engine speed in advance as in the past, this idea detects the noise that is actually occurring and reduces the engine speed when the detected noise value exceeds the set noise level. This makes it possible to reliably keep the noise around the work site below the permissible level in any work environment, and the above-mentioned accelerator lever return rotation cylinder has a detection noise value that is lower than the set noise level. It operates when the detected noise level exceeds the set noise level and returns and rotates the accelerator lever, but it does not operate when the detected noise value is lower than the set noise level, so the accelerator can be freely operated until the detected noise value exceeds the set noise level. Since the engine speed can be increased by operating a lever, the working capacity of the civil engineering and material handling machine can be increased to the maximum level without exceeding the allowable noise level. Moreover, in this invention, when the detected noise value exceeds the set noise level while operating the accelerator lever in the direction of increasing the engine speed, the accelerator lever return rotation cylinder operates to return the accelerator lever. Since the cylinder tries to rotate the engine, the return rotational force generated by the cylinder acts as a resistance to the operation of the accelerator lever, and the operator may increase the engine speed even further without noticing that the noise has become louder. Furthermore, since the accelerator lever return rotation cylinder is not engaged with the accelerator lever when the detected noise value is lower than the set noise level, until the detected noise value exceeds the set noise level, The accelerator lever can be easily operated without being subjected to resistance from the cylinder.

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of this invention, with Figure 1 being a side view of the shovel, Figure 2 being a circuit diagram showing the configuration of the noise control device, and Figure 3 being an enlarged view of the middle part of Figure 2. FIG. 7...Engine, 17...Noise detector, 18...
...Noise level setter, 20...Comparator, 25...
Servo valve, 27...Pneumatic cylinder for returning and rotating the accelerator lever, 30...Accelerator lever.

Claims (1)

[Scope of utility model registration request] A noise detector that detects noise during civil engineering cargo handling work, a noise level setting device, and the noise value detected by the noise detector is compared with the noise level set in the setting device, and the detected noise value is the set noise level. The sensor includes a comparator that outputs an engine control signal when the engine exceeds the limit, a cylinder control valve that is activated by the engine control signal from the comparator, and an engaging part that removably engages with the engine's accelerator lever. When the noise value exceeds the set noise level, the control valve is operated to engage the accelerator lever and rotate the accelerator lever back in the direction of lowering the engine speed, and the detected noise value becomes equal to the set noise level. and an accelerator lever return rotation cylinder that moves in the opposite direction by reverse operation of the control valve to release the engagement with the accelerator lever when the accelerator lever becomes lower than the accelerator level. Noise control device.