JP3202636U - Hydraulic drive work machine - Google Patents

Abstract

Provided is a hydraulically-driven work machine that enables stable operation of work equipment without using an oil amount sensor. A hydraulic pump for supplying hydraulic oil in a tank to a hydraulic actuator, position detectors 32 to 35 for detecting an operation position of the hydraulic actuator, and a control means 18 for controlling a discharge flow rate of the hydraulic pump are provided. The control means 18 estimates the amount of oil in the tank from the operating position of the work equipment detected by the position detectors 32 to 35, and when the amount of oil in the tank is less than the reference value, restricts the flow rate of hydraulic oil supplied to the actuator. To enlarge. When the amount of oil in the tank is less than the reference value, the oil temperature is likely to rise, but the flow rate restriction of the working oil is expanded, so that the oil temperature rise can be suppressed. Since the amount of oil in the tank is estimated from the operating position of each work device, it is not necessary to use an oil amount sensor, and manufacturing costs can be suppressed. [Selection] Figure 1

Description

  The present invention relates to a hydraulic drive working machine. More specifically, the present invention relates to a hydraulic drive working machine such as a mobile crane or an aerial work vehicle.

  In hydraulic drive work machines such as mobile cranes and aerial work vehicles, many actuators such as hydraulic cylinders and hydraulic motors are used to operate work equipment such as booms and winches. In order to drive these hydraulic actuators, it is indispensable to supply and discharge the hydraulic oil discharged from the pump. However, when the hydraulic oil to be supplied and discharged reaches a high temperature, problems such as damage to the hydraulic actuator occur.

  Therefore, conventionally, as in Patent Document 1, an oil temperature sensor is installed in the hydraulic oil tank to detect the oil temperature, and when the oil temperature is high, a countermeasure is taken to regulate the hydraulic oil supply amount. By doing this, measures such as predicting oil temperature rise in advance and avoiding high-load operation were taken.

  However, small hydraulic drive work machines such as truck-mounted cranes and truck-mounted aerial work platforms have a small hydraulic oil tank capacity, so depending on the operating state of each hydraulic actuator, the rate of change in the amount of oil in the tank is large. The amount of oil in the tank may be less than expected. And since oil temperature is easy to rise, so that there is little oil quantity, unexpected oil temperature rise may occur.

  For such a problem, an oil amount sensor that detects the oil amount in the tank may be used. However, since the oil amount sensor is expensive, the manufacturing cost of the hydraulically driven working machine is increased.

JP 2013-221527 A

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a hydraulically-driven work machine that enables stable operation of work equipment without using an oil amount sensor that increases the manufacturing price.

A hydraulic drive working machine according to a first device includes a hydraulic actuator that operates a working device of the hydraulic drive work machine, a hydraulic pump that supplies hydraulic oil in a tank to the hydraulic actuator, and a position that detects an operating position of the hydraulic actuator. A detector and control means for controlling the discharge flow rate of the hydraulic pump, the control means estimating the amount of oil in the tank from the current operating position of the work equipment detected by the position detector, When the amount of oil in the tank is less than or equal to a reference value, the restriction on the flow rate of hydraulic oil supplied to the actuator is expanded.
The hydraulic drive working machine of the second device is provided with an oil temperature sensor for detecting the oil temperature of the hydraulic oil in the first device, and the control means is configured such that the oil temperature detected by the oil temperature sensor has a reference value. The flow rate restriction of the hydraulic oil supplied to the actuator is expanded when exceeding.
In the hydraulic drive work machine of the third device, in the first or second device, in order to expand the flow rate regulation, a) starting the flow rate regulation, starting the oil temperature of the hydraulic oil from a lower temperature; b) regulating the flow rate. It is characterized by including both or any one of enlarging the reduction amount of the supply flow rate by.

According to the first device, when the amount of oil in the tank is less than the reference value, although the oil temperature is likely to rise, the restriction on the flow rate of the working oil is expanded, so that the oil temperature rise can be suppressed. In addition, since the oil amount in the tank is estimated by detecting the current operation position of each work device with the position detector inherent in the hydraulically driven work machine, the oil amount in the tank is estimated. There is no need to use a quantity sensor. For this reason, manufacturing cost can be suppressed.
According to the second device, the flow rate of the hydraulic oil is regulated after detecting the rise of the hydraulic oil temperature, so that the high-speed operation with high work efficiency is performed and the oil temperature is kept high until the oil temperature does not reach the reference high temperature. When the temperature of the oil becomes high, the restriction on the flow rate of the hydraulic oil is expanded, so that an increase in oil temperature can be suppressed.
According to the third device, the flow rate regulation is performed by a) starting from a lower temperature and b) increasing the reduction amount of the supply flow rate, so that any method can achieve the effect of suppressing the oil temperature rise, and both If they are combined, the oil temperature rise can be more effectively suppressed.

It is a block diagram which shows the control part which concerns on 1st Embodiment of this invention. It is a block diagram which shows the control part which concerns on 2nd Embodiment of this invention. It is explanatory drawing of flow control, (A) shows the case where there is much oil amount, (B) shows the case where there is little oil amount. It is explanatory drawing which shows the relationship between the operating condition of a hydraulic actuator, and the amount of oil in a tank. 1 is a hydraulic circuit diagram of a truck-mounted crane that is an example of a hydraulically driven working machine. (A) is a side view of a truck-mounted crane, (B) is a front view of an outrigger device.

Next, an embodiment of the present invention will be described with reference to the drawings.
The hydraulically-driven work machine according to the present invention is a mobile crane such as a load-type truck crane, an aerial work vehicle, or the like, but is not limited thereto, and includes any work machine.
Hereinafter, a truck-mounted crane will be described as an example.

  A truck-mounted crane to which the present invention is applied is one in which a small crane 40 is mounted on a vehicle frame 53 between a cab 51 and a loading platform 52 of a general-purpose truck 50 as shown in FIG. . In the small crane 40, a post 43 is erected on the upper surface of a gantry 41 via a swivel base 42, and a telescopic boom 44 is attached to the upper end of the post 43, and the undulation between the boom 44 and the swivel base 42 is performed. A cylinder 23 is interposed. Further, as shown in FIG. 6B, the small crane 40 includes an outrigger 46, and the outrigger 46 includes an outer box 47 that is horizontally mounted on the vehicle frame 53, and an inner box 48 that is inserted into the inner box 48 and can be extended. The jack 49 is vertically attached to the tip of the inner box 48. As other forms, there are a rear frame in which a small crane is mounted on the vehicle frame behind the loading platform, and a small crane mounted on the inside of the loading platform.

  As shown in FIG. 5, a hydraulic circuit 10 for a small crane of a truck-mounted crane includes a plurality of hydraulic actuators 21 to 25, a hydraulic pump 12 that supplies hydraulic oil to the hydraulic actuators 21 to 25, and hydraulic actuators 21 to 21. And a hydraulic valve unit 13 interposed between the hydraulic pump 12 and the hydraulic pump 12.

  Each hydraulic actuator includes a boom telescopic hydraulic cylinder 22 for extending and retracting a boom 44 of a small crane, a boom raising and lowering hydraulic cylinder 23 for raising and lowering the boom 44, a winch hydraulic motor 21 for winding and unwinding a hook, and a swing for turning a post 43. The hydraulic cylinder 25 for outriggers, the hydraulic cylinder 24 for outriggers which extend / contract the outrigger 46, etc. are shown. 5 shows only one outrigger hydraulic cylinder 24 in FIG. 5, but actually, as shown in FIG. 4, the two jack cylinders 24a for the jack 49 and the overhang for extending the inner box 48 are provided. And a cylinder 24b.

  Returning again to FIG. The hydraulic pump 12 sucks the hydraulic oil stored in the oil tank 14 and supplies the hydraulic oil to the hydraulic valve unit 13 via the oil passage 15.

  The hydraulic valve unit 13 includes a plurality of switching control valves 13a to 13e that control supply and discharge of hydraulic oil to and from the hydraulic actuators 21 to 25. Each of the switching control valves 13a to 13e is a 3-position 6-port switching control valve, and has a carry-over oil passage that communicates at its neutral position and is shut off at the switching position. The carry-over oil passages of the switching control valves 13a to 13e are connected in series to return the hydraulic oil supplied from the hydraulic pump 12 to the oil tank 14. Each of the switching control valves 13 a to 13 e has a P port connected to the pump oil passage 15 and a T port connected to the oil tank 14. Furthermore, a pair of control ports of each switching control valve 13a-13e are connected to the corresponding hydraulic actuators 21-25.

  Driving means 16 such as an engine or an electric motor is connected to the hydraulic pump 12 and is driven by the driving means 16. The drive means 16 is connected to a rotation speed control means 17 such as an engine control unit or an inverter, and the rotation speed control means 17 controls the rotation speed of the drive means 16. Further, a control means 18 for instructing the rotational speed of the driving means 16 is connected to the rotational speed control means 17.

  Therefore, the rotation speed control means 17 controls the rotation speed of the drive means 16 according to the instruction of the control means 18, thereby controlling the rotation speed of the hydraulic pump 12. In general, the discharge flow rate of a hydraulic pump increases or decreases in proportion to the rotation speed. Therefore, the discharge flow rate of the hydraulic pump 12 can be controlled by the control means 18.

Next, based on FIG. 4 and FIG. 6, the relationship between the expansion / contraction position of the work equipment such as a boom and the tank oil amount will be described.
When the boom extendable hydraulic cylinder 22 is extended, the boom 44 is extended, but a large amount of hydraulic oil is supplied into the hydraulic cylinder 22. In this state, the amount of oil in the tank 14 decreases.
When the boom hoisting hydraulic cylinder 23 is extended, the boom 44 stands up. However, since a large amount of hydraulic oil is supplied into the hydraulic cylinder 23, the amount of oil in the tank is reduced by that amount.

  When the outrigger overhang hydraulic cylinder 24b is extended, the overhang width between the left and right jacks increases, but the hydraulic oil is supplied into the hydraulic cylinder 24b, so the amount of oil in the tank decreases. When the outrigger jack hydraulic cylinder 24a is extended, the jack extends downward and jacks up the vehicle body. However, hydraulic oil is supplied into the hydraulic cylinder 24a. The amount decreases.

  When each of the hydraulic cylinders 22, 23, and 24 is contracted, the boom contracts and collapses, and the outriggers are retracted. The hydraulic oil in each of the hydraulic cylinders 22, 23, and 24 is returned to the tank 14. As a result, the amount of oil in the tank increases.

  As described above, the amount of oil in the tank fluctuates depending on the operating state of each hydraulic actuator. However, if the winch hydraulic motor 21 is driven to wind up / down with a high load while the amount of oil in the tank is decreasing, the oil amount is reduced. The temperature tends to rise. The oil temperature rise is not limited to the winch drive, and for example, the oil temperature easily rises when the boom 44 is repeatedly expanded, undulated and turned.

  The oil temperature of the hydraulic oil in the tank 14 can be detected by a known oil temperature sensor 19. The oil temperature sensor 19 is connected to the control means 18 and inputs the detected oil temperature to the control means 18.

  The oil temperature sensor 19 is not particularly restricted as long as the oil temperature can be detected. The oil temperature can be measured most accurately in the tank 14, but hydraulic oil supply piping and return piping close to the tank 14 may be used.

The control system will be described with reference to FIG.
The following position detector is input to the control means 18.
1. A length detector 32 that detects the extension / contraction length of the boom 44.
Known length detectors include a reel-type detector that feeds a measurement wire in conjunction with the boom length, a stage detection switch that detects an extended boom stage position, and the like.

2. Angle detector 33 for detecting the undulation angle of boom 44
There are a weight-type angle detector attached to the side wall of the boom 22, a reel-type detector in which a measurement wire is drawn out according to the amount of extension of the undulation cylinder, and the like.

3. Raising detector 34 for detecting the raising state of the left and right jacks 48
A pressure sensor 34 for detecting the internal pressure of the jack hydraulic cylinder, a strain detector using a load cell, or the like can be used.

4). Overhang detector 35 for detecting the overhanging state of the left and right jacks 48
An overhang detection switch 35 that detects the overhang position of the outrigger overhang beam, a reel type detector in which a measurement wire is fed out in conjunction with the beam length, or the like can be used.

The control means 18 is composed of a known computer or the like and performs the following control operation.
(1) Oil amount estimation The oil amount in the tank 14 is estimated from the current operation position of each work device such as the boom 44 and the outrigger 48 detected by the position detectors 32, 33, 34, and 35.
(2) Comparison When the amount of oil in the tank 14 is equal to or higher than the reference value, the flow rate restriction when the oil temperature rises does not have to be expanded. Expanding.
In order to expand the flow rate regulation, either or both of a) starting the flow rate regulation, starting the oil temperature of the hydraulic oil from a lower temperature, and b) increasing the reduction amount of the supply flow rate by the flow rate regulation. Including.

An example of the above flow rate control will be described in detail with reference to FIG. 3 (A) and 3 (B), symbols W, X, Y, and Z indicate flow rates, and symbols A, B, C, D, and E indicate oil temperatures. The flow rate W side is larger than the Z side, and the oil temperature A side is higher than the E side.
When the amount of oil in the tank is large, as shown in FIG. 3A, the oil can be used at a fixed maximum flow rate W [L / min] until the oil temperature D [° C.] is reached. When the oil temperature exceeds D [° C.], the maximum flow rate decreases linearly, and at the oil temperature C [° C.], the maximum flow rate becomes X [L / min]. Furthermore, when the oil temperature C [° C.] is exceeded, the reduction rate increases, and the maximum flow rate becomes Z [L / min] at the oil temperature B [° C.]. When the oil temperature A [° C.] is reached, the operation itself is stopped.

  When the amount of oil in the tank is small, as shown in FIG. 3B, the flow rate regulation starts early and the regulation value also increases. Specifically, since the regulation starts at the oil temperature E [° C.], it is several degrees earlier than the regulation start temperature D [° C.] when the amount of oil is large. Since the regulation value up to the oil temperature C [° C.] decreases linearly from W [L / min] to Y [L / min], there are many regulations. The maximum flow rate when the oil temperature B [° C.] is reached is Z [L / min], and when the oil temperature A [° C.] is reached, the operation is stopped as in the case where the oil amount is large.

A control procedure using the control device A of FIG. 1 will be described.
The control means 18 estimates the amount of oil in the tank 14 based on the signals from the position detectors 32 to 35. When the amount of oil in the tank is less than the reference value, the oil temperature is likely to rise, so the flow rate regulation of the hydraulic oil is expanded. For example, the flow rate regulation in FIG. In this way, an increase in oil temperature can be suppressed by reducing the hydraulic oil flow rate.

A control procedure using the control device B of FIG. 2 will be described.
In the present embodiment, as shown in FIG. 2, an oil temperature sensor 19 that detects the oil temperature of the hydraulic oil is provided, and the control means 18 detects when the oil temperature detected by the oil temperature sensor 19 exceeds a reference value. In addition, the restriction on the flow rate of hydraulic oil supplied to the actuator is expanded.

  In this embodiment, since the flow rate of the hydraulic oil is regulated after detecting the rise in the hydraulic oil temperature, high-speed operation with high work efficiency is performed and the hydraulic oil is heated to a high temperature while the oil temperature does not reach the reference high temperature. When this happens, the flow restriction of the hydraulic oil is expanded, so that an increase in the oil temperature can be suppressed.

  In each of the above-described embodiments, the amount of oil in the tank is estimated after the current operation position of each work device is detected by the position detectors 32 to 35 originally provided in the hydraulically driven work machine. The manufacturing cost can be suppressed without using an oil amount sensor for detecting the oil amount in the tank 14.

17 Rotational speed control means 18 Control means 32 Length detector 33 Angle detector 34 Rising detector 35 Overhang detector 19 Oil temperature sensor 13 Hydraulic valve unit 21 Winch hydraulic motor 22 Boom telescopic hydraulic cylinder 23 Boom hoisting Hydraulic cylinder 24 Hydraulic cylinder for outrigger 25 Hydraulic motor for turning

Claims (3)

A hydraulic actuator for operating the work equipment of the hydraulic drive work machine;
A hydraulic pump for supplying hydraulic oil in the tank to the hydraulic actuator;
A position detector for detecting an operating position of the hydraulic actuator;
Control means for controlling the discharge flow rate of the hydraulic pump,
The control means estimates the amount of oil in the tank from the current operating position of the work equipment detected by the position detector, and supplies the hydraulic oil to the actuator when the amount of oil in the tank is below a reference value. Hydraulic drive work machine characterized by expanding the flow rate regulation. An oil temperature sensor for detecting the oil temperature of the hydraulic oil;
2. The hydraulic drive working machine according to claim 1, wherein when the oil temperature detected by the oil temperature sensor exceeds a reference value, the control means expands a restriction on a flow rate of hydraulic oil supplied to the actuator. . In order to expand the flow rate regulation, either or both of a) starting the flow rate regulation, starting the oil temperature of the hydraulic oil from a lower temperature, and b) increasing the reduction amount of the supply flow rate by the flow rate regulation. The hydraulic drive work machine according to claim 1, wherein the hydraulic drive work machine is included.

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