JPH0748862A - Speed control device for working machine - Google Patents

Abstract

PURPOSE:To attain the proper traveling speed in any working environment or the traveling environment. CONSTITUTION:An EEPROM is used for a memory section 94. A maintenance man writes the exciting current value of a solenoid valve 4 into the memory section 94 for a high-speed switch 101 and a low-speed switch 102 respectively via a computer 20 before the start of the work. When the operator of a working machine selects one of the switches 101, 102 according to the working environment or the traveling environment during the work, a controller 91 extracts the corresponding exciting current value from the memory section 94, excites the solenoid valve 4 accordingly, and tilts the swash plate 2a of a travel motor 2. A specific speed characteristic is obtained for the operation quantity of an operation lever 6L. Optional speed characteristics can be obtained by the writing into the memory section 94.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work machine speed control device for controlling a running speed of a work machine having a running function.

[0002]

2. Description of the Related Art Work machines such as hydraulic excavators and cranes are equipped with a hydraulic motor (running motor), and are supplied with pressure oil from a hydraulic pump to rotate the work machine. Drive control of such a traveling motor will be described with reference to the drawings.

FIG. 6 is a diagram showing a conventional drive motor drive control. In this figure, 1 is a hydraulic pump, 1a is a variable displacement mechanism of the hydraulic pump 1 (hereinafter represented by a swash plate),
Reference numeral 2 is a traveling motor, 2a is a variable displacement mechanism of the traveling motor 2 (also represented by a swash plate), 3 is a tilt control piston for tilting the swash plate 2a, and 4 is an electromagnetic control for driving the tilt control piston 3. It is a valve. Reference numeral 5 is a control valve interposed between the hydraulic pump 1 and the traveling motor 2, 6 is a pilot valve for operating the control valve 5, and 6L is an operating lever for the traveling motor 2. Reference numeral 7 is a pilot pump, and 8 is a relief valve of the pilot circuit.

A control unit 9 is composed of a microcomputer and comprises a control section 91, a storage section 92, and an output section 93. Control unit 91
Performs various controls according to the program. The storage unit 92 is composed of a read-only memory (ROM),
Two kinds of exciting current values for the solenoid valve 4, eg 700 m
A and 500 mA are stored in advance. The output unit 93 generates a current according to the signal from the control unit 91, and supplies this to the solenoid valve 4. A traveling speed changeover switch 10 includes a high speed switch 101 and a low speed switch 102.

The operator of the working machine operates either the high speed switch 101 or the low speed switch 102 of the traveling speed changeover switch 10 in consideration of the working environment and the traveling environment before starting the work by the working machine. The control unit 91 determines which of the high speed switch 101 and the low speed switch 102 has been operated, and in response to this, extracts the corresponding excitation current value from the storage unit 92 and outputs it to the output unit 93. In the above example, when the high speed switch 101 is operated, the exciting current value of 700 mA is taken out, and when the low speed switch 102 is operated, the exciting current value of 500 mA is taken out. The output unit 93 outputs the extracted exciting current value to the solenoid valve 4 as an actual current.

The solenoid valve 4 operates according to the output exciting current (the opening becomes larger when the exciting current is large), and accordingly the tilt control piston 3 is driven to tilt the swash plate 2a. Eventually, the swash plate 2a is tilted in response to the operation of the high-speed switch 101 or the low-speed switch 102, and the tilt of the high-speed switch 101 is small and the tilt of the low-speed switch 102 is large.

When the operator operates the operation lever 6L in this state, the pilot valve 6 is operated, the control valve 5 is switched, and the pressure oil of the hydraulic pump 1 is supplied to the traveling motor 2 so that the working machine travels. in this case,
Although the traveling speed changes according to the operation amount of the operation lever 6L, the traveling speed is low when the tilt of the swash plate 2a is large and the traveling speed is high when the tilt of the swash plate 2a is small even with the same operation amount. This allows the operator to drive the work machine according to the environment.

[0008]

By the way, if the work site is a flat ground or an ordinary sloping ground, the structure shown in FIG. 6 does not cause any particular inconvenience. However, a problem arises when the work is performed at a site with a narrow steep slope such as forest road construction. This will be described with reference to FIG.

FIG. 7 is a side view of the hydraulic excavator on a steep slope. In this figure, 11 is a lower traveling body of the hydraulic excavator, which is driven by a traveling motor. Reference numeral 12 denotes an upper swing body which is rotatably supported by the lower traveling body 11, 13 denotes a boom (a work mechanism other than the boom is not shown),
Reference numeral 14 indicates a driver's cab, and 15 indicates an operator. 6L is the same operation lever as shown in FIG. Reference numeral 17 indicates a steep slope on which the hydraulic excavator travels, and 18 indicates a horizontal line. In the case of a steep slope as shown in the figure, the operator 15 naturally takes the low speed switch 1
02 is operated to increase the tilt of the swash plate 2a, and the traveling motor 2 is set to rotate at a low speed.

However, when descending such a steep slope, the operator is inevitably in a forward leaning posture, and the weight of the operator 15 is applied to the operating lever 6L during traveling, so that the operating lever 6L is likely to become a full lever and the operating lever 6L Therefore, it is difficult to perform accurate speed control. If the operating lever 6L becomes a full lever, the speed becomes too fast, which is dangerous, and in some cases, there is a possibility that the driver may overstep the forest road and fall to the cliff, resulting in a personal injury.

An object of the present invention is to solve the above-mentioned problems in the prior art and to provide a speed control device for a working machine capable of arbitrarily obtaining a traveling speed suitable for the environment in any environment. It is in.

[0012]

In order to achieve the above object, the present invention provides a traveling motor driven by a hydraulic pump, a speed control mechanism for controlling the rotation speed of the traveling motor, and a high speed of the traveling motor. In a working machine including a speed characteristic setting unit that sets a side speed characteristic and a low speed side speed characteristic, and a control unit that controls the speed control mechanism according to the speed characteristic set by the speed characteristic setting unit, in the control unit, A storage unit that stores values corresponding to each speed characteristic set in the speed characteristic setting unit, is electrically rewritable, and retains stored contents even when the power is cut off; and the value is written in the storage unit And a connection section for connecting a computer.

[0013]

Before the work by the working machine is started, a computer is connected to the connecting portion, and the computer is used to write the speed characteristic suitable for the working environment or the traveling environment, that is, the value for controlling the speed control mechanism in the storage portion. . When performing work,
The operator can safely drive the work machine only by setting the speed characteristic with the speed characteristic setting unit.

[0014]

The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a diagram showing a speed control device for a working machine according to a first embodiment of the present invention. In this figure, the same or equivalent parts as those shown in FIG. Reference numeral 94 is a storage unit corresponding to the storage unit 92 shown in FIG. 6. The storage unit 92 is constituted by a ROM, whereas the storage unit 94 of the present embodiment is electrically rewritable, In addition, it is composed of a memory element, such as an EEPROM, which retains the stored contents even when the power is cut off. Two
Reference numeral 0 is a portable computer having a display unit 201 and a keyboard 202, 21A is a connector connected to the storage unit 94, and 21B is a connector connected to the computer 20 and electrically coupled to the connector 21A.

Next, the operation of this embodiment will be described. At an appropriate time before starting the work of the work machine, the maintenance staff of the manufacturer of the work machine carries the work with the computer 20 to which the connector 21B is connected at the request of the owner of the work machine or at the time of maintenance patrol. Go to the machine and connect connector 21B to connector 21A. The connector 21A is installed at an appropriate place on the work machine, for example, near a chair in the cab. Next, the maintenance staff listens to the working environment, the traveling environment, the wishes of the operator, etc. from the owner or the operator, and the exciting current values corresponding to the high speed switch 101 and the low speed switch 102 are operated by the connector 21B while operating the keyboard 202 of the computer 20. Storage unit 9 via 21A
Write to 4. As a result, the storage section 94 stores the exciting current value corresponding to the traveling speed most suitable for the work and traveling to be performed.

When the operator operates either the high speed switch 101 or the low speed switch 102, the control section 91 extracts the corresponding exciting current value from the storage section 94 and outputs it to the output section 93. The output unit 93 converts the current value into an actual current, supplies it to the solenoid valve 4, and causes the tilt control piston 3 to tilt the swash plate 2a. That is,
The swash plate 2a is a high speed switch 101 or a low speed switch 102.
It is tilted so that the speed characteristic set by is obtained.

For example, it is assumed that the storage section 94 stores the above-described current values of 700 mA and 500 mA. In this state, when the next work site of the work machine is a steep slope such as a forest road, the above current values stored in the storage unit 94 are not appropriate, and the current values for further lower speed are desirable. In this case, the maintenance person uses the computer 20 to write in the storage unit 94, instead of the above current value, a current value suitable for a work site to be worked, for example, 300 mA and 100 mA. As a result, the tilting of the swash plate 2a becomes even larger than in the case of tilting, and the operating lever 6
Even if the operation amount of L is the same, the traveling speed can be made lower than in the previous case, and safety can be ensured.

FIG. 2 is a characteristic diagram of the traveling speed, in which the abscissa represents the operation amount of the traveling lever and the ordinate represents the traveling speed of the work machine. In the figure, A and B indicate a current value 700 in the storage unit 94.
A traveling speed characteristic when mA and 500 mA are written, A is a traveling speed characteristic when the high speed switch 101 is operated, and B is a traveling speed characteristic when the low speed switch 102 is operated. Further, C and D are traveling speed characteristics when current values of 300 mA and 100 mA are written in the storage unit 94, C is a traveling speed characteristic when the high speed switch 101 is operated, and D is when the low speed switch 102 is operated. Is a traveling speed characteristic of.

As described above, in the present embodiment, since the storage element, eg, the EEPROM, which can be electrically rewritten in the storage section and retains the stored contents even when the power is cut off, is used in the storage section. The exciting current value for making the traveling speed suitable for the working environment and traveling environment can be arbitrarily written, and the optimal traveling speed at the work site can be obtained.

In addition, since the storage unit uses a storage element that retains the stored contents even when the power is turned off, no attention is required when replacing or inspecting the battery. Is effective when used for frequent hydraulic excavators.

FIG. 3 is a diagram showing a speed control device for a working machine according to a second embodiment of the present invention. In this figure, parts that are the same as or equivalent to the parts shown in FIG. In the first embodiment, the output of the solenoid valve 4 is used to control the swash plate 2a of the traveling motor 2, but in the present embodiment, it is used to control the swash plate 1a of the hydraulic pump 1. That is, in FIG. 3, reference numeral 30 denotes a tilt control piston of the swash plate 1 a, and the tilt control piston 30 is controlled by the solenoid valve 4. In this way, by controlling the swash plate 1a, the hydraulic pump 1
Since the discharge flow rate of the high speed switch 10 is also controlled,
By selecting 1 or the low speed switch 102, the rotation speed of the traveling motor 2, that is, the traveling speed of the work machine can be controlled. The effect of this embodiment is the same as the effect of the first embodiment.

FIG. 4 is a diagram showing a speed control device for a working machine according to a third embodiment of the present invention. In this figure, the same or equivalent parts as those shown in FIGS. 1 and 3 are designated by the same reference numerals, and the description thereof will be omitted. In the second embodiment, the output of the solenoid valve 4 is used to control the swash plate 1a of the hydraulic pump 1, but in the present embodiment, it is used to control the throttle valve that controls the discharge flow rate of the hydraulic pump 1. That is, in FIG. 4, 40 is a throttle valve interposed between the hydraulic pump 1 and the control valve 5. By controlling the throttle of the throttle valve 40 by the output of the solenoid valve 4, the traveling motor 2 can be operated in exactly the same manner as in the second embodiment.
The rotation speed of the work machine, that is, the traveling speed of the work machine can be controlled. The effect of this embodiment is the same as the effect of the first embodiment.

FIG. 5 is a diagram showing a speed control device for a working machine according to a fourth embodiment of the present invention. In this figure, the same or equivalent parts as those shown in FIGS. 1, 3 and 4 are designated by the same reference numerals and the description thereof will be omitted. In the third embodiment, the output of the solenoid valve 4 is used to control the throttle valve 40 that controls the discharge flow rate of the hydraulic pump 1. However, in the present embodiment, the solenoid valve 4 is not used and the hydraulic pump 4 is not used. A means for controlling the discharge flow rate of No. 1 by a control valve of an electromagnetic / hydraulic control system driven by an exciting current from the control unit 9 is used. The electromagnetic / hydraulic control type control valve is a type of control valve that introduces pilot pressure corresponding to an input signal into its pilot port.

In FIG. 5, reference numeral 50 is a control valve of the electromagnetic / hydraulic control system, which is used in place of the control valve 5 in the previous embodiments. Reference numeral 60 is a traveling electric lever, and 60L is an operating lever thereof, and the traveling electric lever 60 outputs an electric signal according to the operation amount and the operating direction of the operation lever 60L. Reference numeral 95 is a storage unit corresponding to the storage unit 94 in each of the above-described embodiments, but the excitation current of the solenoid valve 4 is written in the former, whereas
In the storage unit 95 of the present embodiment, the attenuation rate for the operation amount signal from the traveling electric lever 60 is written in association with the high speed switch 101 and the low speed switch 102.

As in the previous embodiments, the maintenance personnel use the computer 20 to store the above-mentioned attenuation rate in the storage unit 95 (for example, the value corresponding to the high speed switch 101 is 100%, the value corresponding to the low speed switch 102 is 50%, etc.) before starting the work. Write any value). When the operator operates the operation lever 60L during work, the traveling electric lever 60 outputs an electric signal proportional to the operation amount. The control unit 91 takes in the electric signal, and then the high speed switch 101 or the low speed switch 1
The attenuation rate according to the operation of 02 is taken out from the storage unit 95, multiplied by the electric signal, and the multiplication value is output to the output unit 93.

The output unit 93 creates an exciting current corresponding to the multiplied value and outputs it to the control valve 50 of the electromagnetic / hydraulic control system. As a result, the control valve 50 of the electromagnetic / hydraulic control system is driven by an amount corresponding to the exciting current, and controls the discharge flow rate from the hydraulic pump 1. For example, in the case of the forest road work described above, when the operator operates the low speed switch 102, the control unit 91 causes 50% in the above example.
Is taken out, and this is multiplied by the output of the traveling electric lever 60. Therefore, when the operator operates the operation lever 60L, the work machine travels at half the normal traveling speed. The effect of the present embodiment is also the same as the effect of the first embodiment, and since the writing to the storage unit is the attenuation rate with respect to the normal traveling speed, it has the effect of facilitating the setting.

In the description of each of the above-described embodiments, the example in which the maintenance staff of the work machine manufacturing company writes in the storage unit is described, but this is because the danger at the time of self-writing is taken into consideration and the If there is no fear, anyone who has knowledge of the writing method using the computer 20, such as the owner, manager, and operator of the work machine, can write. Further, in the description of the above embodiment, an example in which a computer is carried and connected to a connector for writing is described, but the computer may be attached to a work machine.
However, in this case, it is necessary to take measures against dust and vibration. Furthermore, in the description of the above embodiments, an example in which a computer is connected by a connector has been described, but it is also possible to connect the computer to the interface of the control unit and perform writing via the control unit.

[0028]

As described above, according to the present invention, a memory element that is electrically rewritable in the memory section and retains the stored contents even when the power is cut off is used, and the speed characteristic setting section uses the memory element. Since an arbitrary value is written by the computer as the set characteristic, the traveling speed suitable for the working environment or the traveling environment can be arbitrarily obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a speed control device for a work machine according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating traveling speed characteristics of the device shown in FIG.

FIG. 3 is a diagram showing a speed control device for a working machine according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a speed control device for a working machine according to a third embodiment of the present invention.

FIG. 5 is a diagram showing a speed control device for a working machine according to a fourth embodiment of the present invention.

FIG. 6 is a diagram showing a conventional speed control device for a work machine.

FIG. 7 is a side view showing a working state of the hydraulic excavator.

[Explanation of symbols]

 1 Hydraulic Pump 2 Travel Motor 2a Swash Plate 3 Tilt Control Piston 4 Solenoid Valve 5 Control Valve 6L Operating Lever 9 Control Unit 91 Control Unit 93 Output Unit 94 Storage Unit 10 Travel Speed Change Switch 20 Computer 21A, 21B Connector

Claims (6)

[Claims] 1. A traveling motor driven by a hydraulic pump, a speed control mechanism for controlling the rotation speed of the traveling motor, and a speed characteristic setting section for setting a high speed side speed characteristic and a low speed side speed characteristic of the traveling motor. In a working machine including a control unit that controls the speed control mechanism according to the speed characteristic set by the speed characteristic setting unit, the control unit corresponds to each speed characteristic set in the speed characteristic setting unit. A work characterized in that a storage unit that stores a value, is electrically rewritable, and retains the stored content even when the power is cut off, and a connection unit that connects a computer that writes the value to the storage unit are provided. Machine speed controller. 2. The work machine according to claim 1, wherein the speed control mechanism is a tilt control piston of a displacement control mechanism of the running motor and a solenoid valve for controlling the tilt control piston. Speed control device. 3. The working machine according to claim 1, wherein the speed control mechanism is a tilt control piston of a variable displacement mechanism of the hydraulic pump and a solenoid valve for controlling the tilt control piston. Speed control device. 4. The speed of a working machine according to claim 1, wherein the speed control mechanism is a throttle valve that limits the supply of the amount of oil to the traveling motor and an electromagnetic valve that controls the throttle valve. Control device. 5. The speed control device for a working machine according to claim 1, wherein the speed control mechanism is a control valve of an electromagnetic / hydraulic control system that controls supply of an amount of oil to the traveling motor. 6. The EE according to claim 1, wherein the storage unit is EE.
A speed control device for a working machine, which is a PROM.