JP2002087789A - Battery-driven working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery-driven working machine capable of extending a work time by a D.C. electric motor 14 by minimizing the consumption of a battery 13 in a battery-driven working machine provided with the D.C. electric motor 14 driven by the battery 13, a hydraulic pump 15 driven by the D.C. electric motor 14, and plural hydraulic actuators 7, 8 and 9 driven by discharge oil from the hydraulic pump 15. SOLUTION: This working machine is characterized by comprising a hydraulic actuator demand flow rate detection means 20 for detecting a demand flow rate required for driving the respective hydraulic actuators 7, 8 and 9, a chopper circuit 21 interlaid between the battery 13 and the D.C. electric motor 14, and a control means 22 for outputting a control signal to the chopper circuit 21 so as to change the duty ratio of the chopper circuit 21 by receiving the respective signals from the hydraulic actuator demand flow rate detection means 20 to relate them to the respective demand flow rates of the respective hydraulic actuators.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a battery, a DC electric motor driven by the battery, a hydraulic pump driven by the DC electric motor, and a plurality of hydraulic actuators driven by oil discharged from the hydraulic pump. The present invention relates to a battery-operated working machine, comprising: operating means for controlling the driving of a plurality of hydraulic actuators; and driving the plurality of hydraulic actuators based on the operation of the operating means.

[0002]

2. Description of the Related Art As a battery working machine of this type, a
There is an aerial work vehicle A as shown in the figure. In this aerial work vehicle A, a swivel base 2 is disposed on a vehicle 1 so as to be freely rotatable, and a telescopic boom B is disposed on the swivel base 2 so as to be able to undulate. The telescopic boom B has a base boom 3 with an intermediate boom 4 and a leading boom 5 sequentially and telescopically inserted therein, and a telescopic driving device (not shown) such as a telescopic hydraulic cylinder 7 disposed between the respective booms. B is made extendable. An undulating hydraulic cylinder 8 is disposed between the base boom 3 and the swivel base 2 at appropriate positions, so that the telescopic boom B can be undulated. Vehicle 1 and turntable 2
A turning drive device (not shown) that turns the telescopic boom B with respect to the vehicle 1 by the turning hydraulic motor 9 or the like.
Is placed.

At the tip of the telescopic boom B, there is provided a bucket 6 which can be swung in a horizontal plane, and an operator riding on the bucket 6 has an operating lever 10A,
By operating 11A and 12A (described later), the telescopic boom B is telescopically moved, raised and lowered, and turned, and the bucket 6 is moved to a target position.
To work at heights. That is, as shown in FIG. 4, in order to drive each hydraulic actuator of the telescopic hydraulic cylinder 7, the up-and-down hydraulic cylinder 8, and the turning hydraulic motor 9, the operating means 10, 11, 12 correspond to each hydraulic actuator. It has.

The operating means 10 includes an operation command unit 10B for detecting the operation direction and the operation amount of the operation lever 10A, a controller 10D for receiving a signal from the operation command unit 10B to drive and control the extendable hydraulic cylinder 7, and a control valve. 10C. Similarly, the operation means 11 includes an operation command device 11B for detecting the operation direction and the operation amount of the operation lever 11A, a controller 11D for receiving a signal from the operation command device 11B and driving and controlling the hydraulic cylinder 8 for raising and lowering, and a control valve. 11C. The operation means 12 includes an operation command device 12B for detecting an operation direction and an operation amount of the operation lever 12A, a controller 12D for receiving a signal from the operation command device 12B to drive and control the turning hydraulic motor 9, and a control valve 12C. It consists of.

[0005] By the way, such work with the aerial work vehicle A is used when performing electric work such as electric poles. In this case, since the aerial work vehicle A is installed on a road and work is performed. In the daytime, traffic is heavy, so nighttime work is often performed. However, when working at night, noise became a problem, and aerial work vehicles A
In this case, a DC electric motor using a battery is used as a power source instead of the engine as a noise source. That is, as shown in FIG. 4, an aerial work vehicle provided with a hydraulic source C for driving a hydraulic pump 15 via a DC electric motor 14 driven by a battery 13 is used.

[0006]

By the way, the hydraulic power source C using such a DC electric motor 14 is supplied from the hydraulic pump 15 so that it can be driven at a predetermined speed when the actuators 7, 8, and 9 are at the maximum load. The DC electric motor 14 having the ability to secure the discharge pressure and the discharge oil amount is employed. However, when the telescopic boom 3 is driven down or down, the load becomes relatively light. Therefore, the discharge pressure and the discharge oil amount may be lower at a lower pressure than at the maximum load. , 8, and 9 are driven at the maximum speed so that the DC electric motor 14 is driven. Therefore, the discharge pressure and the discharge oil amount at a relatively light load may be lower at a lower pressure than at the maximum load, and the surplus oil amount is returned from the relief valve 16 to the tank. Was driven in some cases. In addition, when the DC electric motor 14 is driven more than necessary, the capacity of the battery is unnecessarily reduced at an early stage, which leads to shortening of the working time by the DC electric motor 14. An object of the present invention is to provide a battery-powered working machine that addresses such a problem.

[0007]

In order to achieve the above-mentioned object, a battery-powered working machine according to the present invention is provided with the following means for solving the problems.

(1) The first aspect of the present invention is a battery-driven working machine according to the present invention, comprising a battery, a DC electric motor driven by the battery, a hydraulic pump driven by the DC electric motor, and discharge from the hydraulic pump. A plurality of hydraulic actuators driven by oil, and operating means for driving and controlling the plurality of hydraulic actuators, respectively, in a battery-powered working machine configured to drive the plurality of hydraulic actuators based on the operation of the operating means, Hydraulic actuator required flow rate detecting means for detecting a required flow rate required to drive the hydraulic actuator, a chopper circuit inserted between the battery and the DC electric motor, and a signal from each of the hydraulic actuator required flow rate detecting means. Chopper circuit data related to the required flow rate of each hydraulic actuator A control means for outputting a control signal to the chopper circuit so as to change the duty ratio is provided.

(2) Invention of Claim 2 In the construction of the invention of Claim 1, the battery-driven working machine of the present invention is a working machine having a telescopic boom that can be raised and lowered, and the plurality of hydraulic actuators are provided with a telescopic boom. A hydraulic cylinder for expanding and contracting and a hydraulic cylinder for raising and lowering the telescopic boom, wherein the required flow rate detecting means for each hydraulic actuator detects a required flow rate of each hydraulic actuator when driving the hydraulic cylinder for expanding and lowering and the hydraulic cylinder for raising and lowering. It is characterized in that it is configured to perform.

(3) The battery-operated working machine according to the third aspect of the present invention provides a battery, a DC electric motor driven by the battery, a hydraulic pump driven by the DC electric motor, and discharge from the hydraulic pump. A plurality of hydraulic actuators driven by oil, and operating means for driving and controlling the plurality of hydraulic actuators, respectively, in a battery-powered working machine configured to drive the plurality of hydraulic actuators based on the operation of the operating means, Hydraulic actuator required flow rate detecting means for detecting a required flow rate required to drive the hydraulic actuators, load pressure detecting means for detecting a load pressure required to drive the respective hydraulic actuators, and between the battery and the DC electric motor. Chopper circuit interposed in each of the above, each of the load pressure detecting means and each of the hydraulic pressures The chopper circuit receives a signal from the actuator required flow rate detecting means and changes the duty ratio of the chopper circuit in relation to the maximum load pressure and the required flow rate of each hydraulic actuator among the load pressures detected by the respective load pressure detecting means. A control means for outputting a control signal is provided.

(4) The invention according to claim 4 In the invention according to claim 3, the battery-powered working machine according to the present invention is a working machine having a telescopic boom which can be raised and lowered, and the plurality of hydraulic actuators are provided with a telescopic boom. A telescopic hydraulic cylinder for expanding and contracting and an undulating hydraulic cylinder for raising and lowering a telescopic boom, wherein the load pressure detecting means detects a load pressure of each hydraulic actuator when driving the telescopic hydraulic cylinder and the undulating hydraulic cylinder, Each hydraulic actuator required flow rate detecting means is configured to detect a required flow rate of each hydraulic actuator when driving the telescopic hydraulic cylinder and the undulating hydraulic cylinder.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a battery-powered working machine according to the present invention will be described below with reference to FIGS. A case where the embodiment of the battery-driven working machine according to the present invention is applied to the aerial work vehicle A described in the related art will be described below. Therefore, reference numerals 1 to 16, reference numerals A and B, reference numerals 10A to 10
C, symbols 11A to 11C, symbols 12A to 12C
In the following description, the same reference numerals are used, and the detailed description is omitted. (1st Embodiment) 20 is each operation command device 10B, 11
B is a hydraulic actuator required flow rate detecting means that receives signals from B and 12B and detects a required flow rate required to drive each hydraulic actuator. The hydraulic actuator required flow rate detecting means 20 includes the operation command devices 10B, 11B,
The required flow rate required to drive each hydraulic actuator is calculated from a signal based on the operation direction and operation amount of each hydraulic actuator from 12B. The hydraulic actuator required flow rate detecting means 20 previously stores the required flow rate required for each hydraulic actuator based on the operation direction and the operation amount, and is required to drive each hydraulic actuator from the operation direction and the operation amount signal. The required flow rate may be obtained.

Reference numeral 21 denotes a chopper circuit which is interposed between the battery 13 and the DC electric motor 14 and controls a current supplied from the battery 13 to the DC electric motor 14. Is changed based on a control signal from the control means described below.

Reference numeral 22 denotes a signal received from the hydraulic actuator required flow rate detecting means 20, and each of the hydraulic actuators 7,
The duty of the chopper circuit 21 in relation to the required flow rate Q required to drive each of the hydraulic actuators 7, 8, 9 (for example, based on the calculated total value Q of the required flow rates required to drive each of the hydraulic actuators 7, 8, 9) Control means for outputting a signal for determining the ratio.

The duty ratio determined by the control means 22 is such that as the required flow rate increases, the ratio of the non-supply time to the supply time of the supplied current decreases, and as the required flow rate decreases, the duty ratio decreases with respect to the supply time. The ratio of the non-supply time is set to be long, and the duty ratio is changed continuously or stepwise with respect to a change in the required flow rate. However, the duty ratio depends on each hydraulic actuator 7,
Even if the load when driving 8, 9 is relatively light,
It is determined that the DC electric motor 14 is driven so as to obtain a predetermined load pressure.

When the required flow rate is 0 (each operating lever 1
The duty ratio is set such that the current supplied from the battery 13 to the DC electric motor 14 becomes 0 when the 0A, 11A, and 12A are not operated). That is, when the hydraulic actuators 7, 8, 9 are not driven,
Since the oil discharged from the hydraulic pump 15 only returns to the tank and consumes the battery unnecessarily, the DC electric motor 14 is stopped in this case.

The battery-powered working machine according to the present invention having the above-described structure operates as follows. Now, the telescopic boom B is slightly extended or raised (ie,
When the operating levers 10A and 11A are operated to slightly extend and retract the hydraulic cylinder 7 for expansion and contraction and the hydraulic cylinder 8 for raising and lowering, the hydraulic actuator required flow rate detecting means 20 issues an operation command according to the operating levers 10A and 11A at that time. Vessel 1
In response to signals from 0B and 11B, required flow rates required to drive the hydraulic actuators 7 and 8 are obtained.

The control means 22 receives a signal from the hydraulic actuator required flow rate detecting means 20 and obtains an appropriate duty ratio in relation to the required flow rates required to drive each hydraulic actuator. The duty ratio at this time is set to a ratio such that the non-supply time is longer than the supply time of the supplied current because the required flow rate is small. The chopper circuit 21 receives a signal from the control unit 22 and supplies a current from the battery 13 to the DC drive motor 14 at a duty ratio set by the control unit 22.

Therefore, conventionally, the DC drive motor 14 is driven so as to cope with the case where the hydraulic actuators 7, 8, 9 are driven at the maximum speed, and the hydraulic actuators 7, 8, 9 are driven at a low speed. Although the excess oil was returned to the tank by the relief valve 16 and the current from the batchy 13 was consumed unnecessarily, the duty ratio was determined so that the hydraulic pump 15 supplied a flow rate corresponding to the required flow rate. Since the motor 14 is driven, the operation time of the DC electric motor 14 can be extended correspondingly without consuming wasteful current from the battery 13.

(Second Embodiment) In the first embodiment,
Even when the hydraulic actuators 7, 8, 9 are driven with a relatively light load, the DC motor 14 is driven by setting the duty ratio so that a predetermined load pressure can be obtained. FIG. 2 shows a case where the DC pressure motor 14 is driven more efficiently by detecting the load pressure at the time of driving 7, 8, 9 and will be described below.

Reference numerals 25, 26 and 27 denote load pressure detecting means for detecting load pressures required for driving the hydraulic actuators 7, 8, and 9, respectively. 28 receives a signal from the hydraulic actuator required flow rate detection means 20 and a detection signal from each of the load pressure detection means 25, 26, 27, and receives a load pressure detected by each of the load pressure detection means 25, 26, 27. In relation to the maximum load pressure P and the required flow rate Q required to drive each hydraulic actuator (for example, the product of the maximum load pressure P and the calculated total value Q of the required flow rates required to drive each hydraulic actuator) Based on) chopper circuit 2
Control means for outputting a signal for determining a duty ratio of 1.

Here, the duty ratio determined by the control means 28 decreases the ratio of the non-supply time to the supply time of the supplied current as the required flow rate increases, and decreases the supply time as the required flow rate decreases. The ratio of the non-supply time is set to be longer in the same manner as in the first embodiment. However, in the case of the present embodiment, each hydraulic actuator 7,
The duty ratio is determined also on the basis of the load pressure necessary for driving 8, 9. That is, the duty ratio is determined corresponding to the maximum load pressure among the hydraulic actuators 7, 8, 9 to be driven, and any of the hydraulic actuators 7, 8, 9 is required to drive each of the hydraulic actuators 7, 8, 9. , 9 require only a small load pressure, the duty ratio of the current supplied to the DC electric motor 14 is set so as to increase the ratio of the non-supply time to the current supply time.

When the required flow rate is 0 (each operating lever 1
0A, 11A, and 12A are not operated), the duty ratio is set such that the current supplied from the battery 13 to the DC electric motor 14 is 0, which is the same as the control means 22 of the above-described embodiment. It is.

The battery-operated working machine according to the present invention having the above-described structure operates as follows. Now, the telescopic boom B is slightly driven to reduce or fall down (ie,
When each of the operation levers 10A and 11A is operated to slightly reduce the expansion / contraction hydraulic cylinder 7 and the up / down hydraulic cylinder 8, the hydraulic actuator required flow rate detecting means 20 issues an operation command in accordance with each of the operation levers 10A and 11A at that time. Vessel 1
In response to signals from 0B and 11B, required flow rates required to drive the hydraulic actuators 7 and 8 are obtained.

Further, each load pressure detecting means 25, 26
Each load pressure for detecting the load pressure required to drive each of the hydraulic actuators 7 and 8 is detected, and the detected signal is output to the control means 28.

The control means 28 receives the signal from the hydraulic actuator required flow rate detecting means 20 and the load pressure detecting means 2
5 and 26, each load pressure detecting means 25,
A signal for determining the duty ratio of the chopper circuit 21 is output in relation to the maximum load pressure among the load pressures detected at 26 and the required flow rates required to drive each hydraulic actuator. At this time, the duty ratio is such that the telescopic boom B is slightly driven to reduce or fall down, so that the load pressures detected by the load pressure detecting means 25 and 26 are small and the required flow rate is small, so that the DC The duty ratio of the current supplied to the motor 14 is set so as to increase the ratio of the non-supply time to the supply time.

The chopper circuit 21 receives a signal from the control means 28, and receives a signal from the battery 13 at the duty ratio set by the control means 28 as described above.
Supply current to

Therefore, conventionally, the DC drive motor 14 is driven so as to cope with the case where each of the hydraulic actuators 7, 8, 9 is driven at the maximum speed. In this case, each of the hydraulic actuators 7, 8, 9 is driven. When the valve 9 was driven at a low speed, the excess oil was returned to the tank by the relief valve 16 and the current from the batchy 13 was consumed unnecessarily, but the load pressure and the required flow rate required by the hydraulic actuators 7 and 8 were met. Since the DC drive motor 14 is driven by determining the duty ratio, the work time by the DC electric motor 14 can be extended correspondingly without wasting current from the battery 13.

In the above embodiment, each load pressure detecting means 25, 26 directly detects the load pressure required to drive each hydraulic actuator 7, 8, but the state of the telescopic boom B is detected (expanded or contracted). Detecting the state of the telescopic boom B by detecting the telescopic length, undulation angle, and turning angle of the boom B)
The load pressure required to drive each of the hydraulic actuators 7, 8, 9 according to the state of the telescopic boom B is stored in advance as data, and the state of the telescopic boom B is detected (the telescopic length of the telescopic boom B, The state of the telescopic boom B is detected by detecting the angle and the turning angle, and the hydraulic actuators 7,
The load pressure required to drive the motors 8 and 9 may be obtained.

In the above embodiment, the case where the telescopic hydraulic cylinder 7 and the undulating hydraulic cylinder 8 are driven has been described, but the same applies to the case where the turning hydraulic motor 9 is driven. The aerial work vehicle A is provided with many hydraulic actuators in addition to the above-described hydraulic actuators 7, 8, and 9, and detects a required flow rate and a load pressure when the hydraulic actuators are driven. The duty ratio may be determined by the control means 22 or the control means 28 in consideration of the flow rate and the load pressure.

Further, in the above embodiment, the aerial work vehicle A has been described as an example of a battery-driven working machine having a boom. However, the present invention can also be applied to a working machine having a boom such as a mobile crane or an excavator. Needless to say, the present invention can be applied to other working machines.

[0032]

The battery-operated working machine of the present invention drives a DC electric motor by determining a required flow rate required by each hydraulic actuator or a duty ratio corresponding to a load pressure and a required flow rate of each hydraulic actuator. Therefore, the battery consumption can be prevented as much as possible, and the working time by the DC electric motor can be prolonged accordingly.

[Brief description of the drawings]

FIG. 1 is an explanatory view illustrating a battery-driven working machine according to the present invention.

FIG. 2 is an explanatory diagram illustrating a battery-driven working machine according to the present invention, and is an explanatory diagram illustrating another embodiment.

FIG. 3 is an explanatory view illustrating an aerial work vehicle as a battery-driven work machine.

FIG. 4 is an explanatory view illustrating a conventional battery-driven working machine.

[Explanation of symbols]

 7 Hydraulic Actuator (Hydraulic Cylinder for Telescoping) 8 Hydraulic Actuator (Hydraulic Cylinder for Up / Down) 9 Hydraulic Actuator (Hydraulic Motor for Turning) 10 Operating Means 11 Operating Means 12 Operating Means 13 Battery 14 DC Electric Motor 15 Hydraulic Pump 20 Required Hydraulic Actuator Flow Detecting means 21 Chopper circuit 22 Control means 25 Load pressure detecting means 26 Load pressure detecting means 27 Load pressure detecting means 28 Control means A Aerial work platform B Telescopic boom

Claims (4)

[Claims] 1. A battery, a DC electric motor driven by the battery, a hydraulic pump driven by the DC electric motor, a plurality of hydraulic actuators driven by oil discharged from the hydraulic pump, and a plurality of hydraulic actuators Operating means for controlling each of the hydraulic actuators, and for driving a plurality of hydraulic actuators based on the operation of the operating means, a hydraulic pressure for detecting a required flow rate required to drive each hydraulic actuator, Actuator required flow rate detection means, a chopper circuit interposed between the battery and the DC electric motor, and a signal from each of the hydraulic actuator required flow rate detection means, the duty of the chopper circuit being related to the required flow rate of each hydraulic actuator. Control signal to the chopper circuit to change the ratio A battery-operated working machine comprising a control means for outputting a signal. 2. The work machine having a battery-operated working machine having a telescopic boom that can be raised and lowered, wherein the plurality of hydraulic actuators are a hydraulic cylinder for expanding and contracting a telescopic boom and a hydraulic cylinder for raising and lowering a telescopic boom. ,
2. The battery driving operation according to claim 1, wherein each of the hydraulic actuator required flow rate detecting means is configured to detect a required flow rate of each hydraulic actuator when driving the telescopic hydraulic cylinder and the undulating hydraulic cylinder. Machine. 3. A battery, a DC electric motor driven by the battery, a hydraulic pump driven by the DC electric motor, a plurality of hydraulic actuators driven by oil discharged from the hydraulic pump, and a plurality of hydraulic actuators Operating means for controlling each of the hydraulic actuators, and for driving a plurality of hydraulic actuators based on the operation of the operating means, a hydraulic pressure for detecting a required flow rate required to drive each hydraulic actuator, Actuator required flow rate detection means, load pressure detection means for detecting the load pressure required to drive each hydraulic actuator, a chopper circuit inserted between the battery and the DC electric motor,
The duty of the chopper circuit is determined in relation to the maximum load pressure and the required flow rate of each hydraulic actuator among the load pressures detected by the load pressure detecting means in response to the signals from the load pressure detecting means and the hydraulic actuator required flow rate detecting means. A battery-operated working machine comprising a control unit for outputting a control signal to the chopper circuit so as to change a ratio. 4. The work machine having a battery-operated working machine having a telescopic boom that can be raised and lowered, wherein the plurality of hydraulic actuators are a hydraulic cylinder for expanding and contracting a telescopic boom and a hydraulic cylinder for raising and lowering a telescopic boom. ,
The load pressure detecting means detects a load pressure of each hydraulic actuator when driving the telescopic hydraulic cylinder and the undulating hydraulic cylinder, and each hydraulic actuator required flow rate detecting means drives the telescopic hydraulic cylinder and the undulating hydraulic cylinder. 4. The battery-operated working machine according to claim 3, wherein a required flow rate of each hydraulic actuator is detected when the operation is performed.