JP7453015B2 - Travel control device for aerial work vehicles - Google Patents

Description

TECHNICAL FIELD The present invention relates to a travel control device for an aerial work vehicle that is configured to allow travel operations to be performed from a workbench provided at the tip of a boom.

An example of an aerial work vehicle includes a traveling body that has wheels and can travel, a rotating body that is installed on the traveling body so that it can rotate horizontally, and a boom that is installed on the rotating body so that it can be raised and retracted. 2. Description of the Related Art A self-propelled aerial work vehicle is known that includes a work platform that is rotatably supported at the tip of a boom. For example, as described in Patent Document 1, such a high-altitude work vehicle includes: An operating device is provided on the work platform, and by operating the operating device, it is possible to perform the rotating operation of the revolving body, the raising and lowering operation of the boom, and the rotating (oscillating) operation of the work platform. , it is also configured to allow the traveling body to travel. The operating device is also provided with a travel lever that extends upward and can be tilted forward or backward from a neutral state, and a steering lever that can be tilted left or right. It is configured to move the wheels forward or backward, to control their traveling speed, and to change the steering angle of the wheels in accordance with the tilting operation of the steering lever.

Japanese Patent Application Publication No. 2001-180899

In the self-propelled aerial work vehicle described in Patent Document 1, depending on the steering angle of the steering wheel, the traveling speed of the vehicle body becomes lower than the traveling speed at which it can safely turn (permissible traveling speed). It is restricted as follows. However, in general, in this type of self-propelled aerial work vehicle, the steering angle always changes at a constant speed regardless of the traveling speed. The course change of the traveling body responds too sensitively to the operator's steering operation, making it difficult to operate the traveling body, and the work platform supported at the tip of the boom may move suddenly. As a result, there is a problem in that the riding comfort of the worker on the workbench becomes poor.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a travel control device for a high-altitude work vehicle that can improve the operability of a traveling body.

In order to solve the above problems, a traveling control device for an aerial work vehicle according to the present invention includes: a traveling body that is equipped with steering wheels and can travel; a revolving body that is rotatably provided on the traveling body; a boom that can be raised and lowered freely; a workbench provided at the tip of the boom on which a worker can ride; and a steering operation provided on the workbench and operated by a worker on the workbench. A device (for example, the steering lever 72 in the embodiment), a steering actuator (for example, the steering cylinder 66 in the embodiment) that performs a steering operation of the steering wheel, and an operation of the steering actuator in response to the operation of the steering operation device. A travel control device for an aerial work vehicle comprising: a steering actuator control device (for example, the steering angle control unit 52 in the embodiment) that controls a speed index value indicating a travel speed of the traveling body; The steering actuator control device includes a speed index value detection device (for example, the steering angle control unit 52 in the embodiment) that detects the operation speed of the steering actuator according to the operation of the steering operation device, and The speed index value detected by the value detection device is configured to be corrected to become slower as the speed index value increases .

In the travel control device for an aerial work vehicle having the above configuration, the steering actuator control device controls the steering operation device when the speed index value detected by the speed index value detection device is less than a predetermined value. Preferably , the operating speed of the steering actuator in accordance with the operation is not corrected .

In the travel control device for an aerial work vehicle having the above configuration, preferably, the steering actuator control device detects the operating speed of the steering actuator while the steering operation device is operated by the speed index value detection device. The operating speed is controlled so that the operating speed corresponds to the speed index value detected by.

Furthermore, in the travel control device for a high-altitude work vehicle having the above configuration, preferably a travel operation device (for example, the travel operation lever 71 in the embodiment) provided on the work platform and operated by a worker on the work platform ), and a traveling speed control device (for example, the controller 50 in the embodiment) that controls the traveling speed of the traveling object according to the operation of the traveling operation device, and the speed index value detection device is configured to control the traveling speed of the traveling object according to the operation of the traveling operation device. The speed index value is detected based on the operation of the device.

According to the travel control device for an aerial work vehicle according to the present invention, the steering actuator control device determines the operating speed of the steering actuator in accordance with the operation of the steering operation device based on the speed index value detected by the speed index value detection device. Correct it so that it becomes slower as it increases . As a result , it is possible to prevent the course change of the traveling object from responding too sensitively to the operator 's steering operation when the traveling speed is high, and as a result, the operability of the traveling object can be improved. can.

In the travel control device for an aerial work vehicle having the above configuration, when the speed index value detected by the speed index value detection device is less than a predetermined value, the steering actuator control device controls the operation of the steering operation device. It is preferable that the operating speed of the steering actuator is not corrected in accordance with the steering actuator. When the vehicle is traveling at a low speed, there is no risk of the vehicle changing course responding too sensitively, so conventional steering control is performed.

Furthermore, in the travel control device for a high-altitude work vehicle configured as described above, a travel operation device operated by a worker on the work platform is provided on the work platform, and the travel speed of the traveling object is controlled in accordance with the operation of the travel operation device. The vehicle may be configured to include a traveling speed control device for controlling the vehicle, and the speed index value detection device may detect the speed index value based on the operation of the traveling operation device. In this case, there is no need to separately add a meter for measuring the traveling speed of the traveling object, so an increase in manufacturing costs and manufacturing steps can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view and a plan view of a self-propelled aerial work vehicle, which is an example of an aerial work vehicle according to the present invention. FIG. 2 is a block diagram showing an operation control configuration of the above-mentioned aerial work vehicle. It is a hydraulic circuit diagram showing a part of the steering control configuration of the above-mentioned aerial work vehicle. It is a graph showing the relationship between the amount of operation of the travel control lever of the above-mentioned aerial work vehicle and the flow rate of hydraulic oil for displacing the steering angle.

Embodiments of the present invention will be described below with reference to the drawings. As an example of the vehicle for aerial work according to the present invention, a self-propelled vehicle for aerial work 1 is shown in FIG. The aerial work vehicle 1 includes a traveling body 10 configured to be able to run, a revolving body 20 provided on the upper part of the traveling body 10 and capable of turning in the horizontal direction, and a revolving body 20 provided on the upper part of the revolving body 20 and capable of raising and lowering. It is configured to include a boom 30 and a workbench 40 provided at the tip of the boom 30.

The traveling body 10 includes a pair of left and right steering wheels 12 (a left steering wheel 12L and a right steering wheel 12R) rotatably provided on a traveling body frame 11, and a pair of left and right drive wheels 13 (a left drive wheel 13L and a right drive wheel). 13R). Note that, as shown in FIG. 1(a), the traveling body 10 is moving toward the left in the drawing as forward movement, and moving toward the right in the drawing is called backward movement. The steering operation (displacement operation of the steering angle) of the left steering wheel 12L and the right steering wheel 12R is configured to be performed by the steering device 60. The steering device 60 includes a steering bracket 61 that is pivotally connected to the vehicle frame 11 by a king pin 62 and rotatably supports the corresponding steered wheel 12, and a force that rotates the steering bracket 61 about the king pin 62 (as well as It has a knuckle arm 63 for transmitting a force for steering the steering wheel 12.

Here, the steering bracket 61, king pin 62, and knuckle arm 63 are provided corresponding to the left steering wheel 12L and the right steering wheel 12R, respectively, and the steering bracket 61, king pin 62, and knuckle arm 63 for the left steering wheel 12L are provided. The character "left" is added to the beginning of each name, and "L" is added to the end of each code. Each symbol is written with the character "right" added to the beginning and "R" added to the end of each code. Note that in FIG. 1(b), the left knuckle arm 63L is hidden behind a steering cylinder 66 and a steering arm 67, which will be described later.

The left knuckle arm 63L and the right knuckle arm 63R are connected by a tie rod 64. Specifically, one end of the tie rod 64 is rotatably fixed to the left knuckle arm 63L by a left connecting pin 65L, and the other end of the tie rod 64 is rotatably fixed to the right knuckle arm 63R by a right connecting pin 65R. ing. As described above, since the left and right knuckle arms are connected by the tie rod 64, each steering bracket rotates in conjunction with each other (and the steering angle of the steering wheel 12 is displaced in conjunction with each other). ing.

Further, the left steering bracket 61L is provided with a steering arm 67 for connecting to a steering cylinder 66 that is a drive source for displacing the steering angle of the left and right steering wheels 12, and the steering cylinder 66 and the steering arm 67 are connected to each other by cylinder connection. They are connected by a pin 68. As a result, the left steering bracket 61L rotates about the left king pin 62L in accordance with the expansion and contraction of the rod of the steering cylinder 66. Further, the movement of the left steering bracket 61L is transmitted to the right knuckle arm 63R via the tie rod 64, and the right steering bracket 61R rotates about the right king pin 62R in conjunction with the movement of the left steering bracket 61L. . In the steering device 60 shown in FIG. 1B, when the cylinder rod of the steering cylinder 66 extends from the neutral position, the steering angle of the steering wheel 12 is aligned with the center line (see FIG. (b) If the traveling body 10 is displaced to the left from the dashed dotted line) and moves forward in this state, the traveling direction of the traveling body 10 will turn to the right. Further, when the cylinder rod of the steering cylinder 66 contracts from the neutral position, the steering angle of the steering wheel 12 is displaced from the center line to the right when looking in the direction of the rotating body 20 from the workbench 40, and when moving forward in this state, The traveling direction of the traveling body 10 is to turn to the left.

A turning mechanism 15 is provided at the center of the upper part of the traveling body frame 11, and the turning mechanism 15 is configured to turn the rotating body 20 in the direction shown by arrow A in FIG. 1(b). The swing mechanism 15 includes an outer ring fixed to the traveling body frame 11, an inner ring that engages with the outer ring and is fixed to the swing structure 20, and various actuators (described later) provided in the swing structure 20 that are supplied with hydraulic oil. It has a rotary center joint (not shown) for supplying. A boom 30 is provided on the upper part of the revolving structure 20, and is rotatable (undoable) about a pivot pin 34 in the direction shown by arrow A in FIG. 1(a). The boom 30 has a base end boom 31 pivotally connected to the revolving body 20, an intermediate boom 32 nestedly combined with the base end boom 31, and a tip boom 33, and these booms are configured to be extendable and retractable. ing. A vertical post 37 is provided at the tip of the tip boom 33 so as to be swingable in the vertical direction by means of a pivot pin 33a.

A workbench 40 is provided on the top of the vertical post 37 so as to be pivotable (swingable) about the pivot pin 37a in the direction shown by arrow C in FIG. 1(b). The workbench 40 has a substantially rectangular workfloor 41 on which a worker M can ride, and a handrail 42 erected around the workfloor 41. The workbench 40 is provided with an operating device 70 for controlling the traveling of the traveling body 10, the operation of the boom 30, and the like.

Next, a control device that controls traveling of the traveling body 10 and controls the operation of the rotating body 20, the boom 30, and the workbench 40 based on the operation of the operating device 70 will be described with reference to FIG. This control device controls various actuators that operate the traveling body 10, the rotating body 20, the boom 30, and the workbench 40, and includes the operation device 70 provided on the workbench 40 described above and the various actuators described above. Hydraulic unit 80 supplies hydraulic oil to various actuators as a drive source, and hydraulic oil is supplied from hydraulic unit 80 to various actuators in response to operations on various operating levers provided on rotating body 20 and provided on operating device 70. and a controller 50 that controls the.

The actuators included in the aerial work vehicle 1 include a travel drive actuator for driving the travel body 10 and an upper drive actuator for driving the movement of the revolving body 20, boom 30, and work platform 40. There is. In this embodiment, the traveling drive actuators include a traveling actuator that moves the traveling body 10 forward or backward in a predetermined speed range, a steering actuator that performs a steering operation of the steering wheels 12, and a brake that brakes the traveling body 10 while traveling. It is equipped with an actuator. The travel motor 16 shown in FIG. 2 corresponds to a travel actuator, the steering cylinder 66 corresponds to a steering actuator, and the brake cylinder 18 corresponds to a braking actuator. Further, as an actuator for driving the upper part, a swing motor 26, a boom hoisting cylinder 35, a boom telescoping cylinder 36, and a swinging motor 46 are provided.

The travel motor 16 transmits the rotation of the motor shaft driven by the hydraulic pressure of the supplied hydraulic oil to the drive wheels 13 (see FIG. 1), and rotates the drive wheels 13 in the normal direction by rotating the motor shaft in the normal or reverse direction. or reverse, thereby moving the traveling body 10 (see FIG. 1) forward or backward. Furthermore, the running speed of the traveling body 10 is changed by controlling the rotational speed of the motor shaft. The brake cylinder 18 is a negative brake that brakes and locks the rotation of the motor shaft of the travel motor 16 by the force of a built-in spring and brakes the rotation of the drive wheels 13 when it is not supplied with hydraulic oil. The steering cylinder 66 is a single rod cylinder having two ports, and the tip of the cylinder rod is connected to a steering arm 67 (see FIG. 1(b)), and the steering wheel 12 is operated by expansion and contraction of this cylinder rod. let

The swing motor 26 is installed on the swing body 20, and transmits the rotation of the motor shaft to an inner ring that engages with an outer ring fixed to the traveling body frame 11, and rotates the swing motor 26 in the normal or reverse direction. 20 is turned clockwise or counterclockwise with respect to the traveling body 10 (see arrow A in FIG. 1(b)). The boom hoisting cylinder 35 is installed astride between the rotating body 20 and the boom 30, and by extending and contracting the cylinder rod, the boom 30 is hoisted in the direction of arrow A in FIG. 1(a) about the pivot pin 34. The boom telescopic cylinder 36 is provided within the boom 30, and by telescoping the cylinder rod, the intermediate boom 32 and the distal boom 33, which are nested together in the proximal boom 31, are telescopically extended.

The swing motor 46 is provided on the workbench 40, and rotates the workbench 40 relative to the vertical post 37 in the direction of arrow C in FIG. It enables rotation operation (oscillation operation). Furthermore, an upper leveling cylinder (not shown) is provided between the tip of the tip boom 33 and the vertical post 37. A closed circuit is formed between this upper leveling cylinder and a lower leveling cylinder (not shown) installed between the base end boom 31 and the revolving structure 20 using a hydraulic hose. The upper leveling cylinder is expanded and contracted in response to the expansion and contraction of the vertical post 37, so that the vertical post 37 is vertically swung relative to the tip boom 33, so that the floor surface of the workbench 40 is always kept level regardless of the up-and-down angle of the boom 30. Configured to hold the state.

The hydraulic unit 80 that supplies hydraulic oil as a drive source for operating the various actuators described above includes an engine E provided in the revolving body 20, a hydraulic pump P driven by the engine E, a hydraulic oil tank T, and a hydraulic oil tank T. It has a control valve unit 85 that controls the supply direction and supply amount of hydraulic oil supplied from the pump P to each hydraulic actuator. The control valve unit 85 has a plurality of control valves provided corresponding to each hydraulic actuator. These plurality of control valves include a travel control valve V1 for driving and controlling the travel motor 16, a brake control valve V2 for controlling the brake cylinder 18, a steering direction switching valve V3 for controlling the steering cylinder 66, and a steering angular velocity valve V3 for controlling the steering cylinder 66. There are a control valve V4, a swing control valve V5, an undulation control valve V6, a telescopic control valve V7, and an oscillation control valve V8.

The operating device 70 constituting the control device shown in FIG. ), a swing operation lever 73 that performs the rotation operation of the rotating body 20, a boom operation lever 74 that performs the raising/lowering and extending/contracting operations of the boom 30, and a swing operation (swivel operation) of the work platform 40. It has a swing operation lever 75. Each of these operating levers is located at a neutral position in which the lever is vertically oriented when not in operation, and is configured to be tiltable in a direction determined for each operating lever based on this neutral position. has been done. Further, the controller 50 controls each control valve in the control valve unit 85 in response to the tilting operation of each operating lever described above.

Hereinafter, control of each control valve in response to a tilting operation of each operating lever will be explained. First, the travel control lever 71 can be tilted forward and backward from the neutral position, and when the travel control lever 71 is tilted forward, the controller 50 controls the travel body 10 to move at a speed corresponding to the tilt angle of the lever. The travel control valve V1 controls the supply direction and flow rate of hydraulic oil to the travel motor 16 so that the vehicle moves forward. On the other hand, when the travel control lever 71 is tilted backward, the direction of supply of hydraulic oil to the travel motor 16 is opposite to that when the travel control lever 71 is tilted forward. The travel control valve V1 is controlled to control the flow rate of hydraulic oil so that the travel control valve V1 moves backward at a speed corresponding to the tilt angle of the lever.

Further, when the traveling operation lever 71 is operated to tilt in either the front or rear direction from the neutral state, the controller 50 opens the brake control valve V2 and supplies hydraulic oil to the brake cylinder 18. As a result, the brake lock state on the motor shaft of the travel motor 16 is released, and the motor shaft becomes rotatable. On the other hand, when the traveling operation lever 71 is in the neutral position or when it returns to the neutral position from the tilted state, the controller 50 closes the brake control valve V2 and controls the brake cylinder 18. Stop the oil supply. As a result, the motor shaft of the travel motor 16 enters a braking lock state, and the rotation of the drive wheels 13 is braked.

The steering lever 72 can be tilted left and right from the neutral position, and the controller 50 causes the steering lever 72 to turn to the left when the vehicle 10 moves forward with the steering lever 72 tilted to the left. When the traveling body 10 moves forward in a state where it is tilted to the right, the steering angle of the steered wheels 12 is changed so that it turns to the right. The steering angle operation of the steered wheels 12 is performed by the steering angle control section 52 in the controller 50 controlling the steering direction switching valve V3 and the steering angle speed control valve V4. The details of the control of the steering direction switching valve V3 and the steering angle speed control valve V4 by the steering angle control section 52 will be described in detail later.

The swing operating lever 73 is configured to be tiltable in the left and right directions from the neutral position, and the controller 50 causes the swing body 20 to rotate clockwise in FIG. 1(b) when the operating lever is tilted in the right direction. , when the lever is tilted to the left, the spool movement direction and valve opening of the swing control valve V5 are controlled so that the swing body 20 rotates counterclockwise in FIG. 1(b), and the swing motor is controlled. 26. The boom operating lever 74 is configured to be tiltable in the front-rear and left-right directions from the neutral position, and when the boom operating lever 74 is tilted in the front-rear direction, the controller 50 controls the spool movement direction of the undulation control valve V6. The control lever is switched in accordance with the tilting direction of the operating lever, and the valve opening is controlled to a predetermined degree, and the boom hoisting cylinder 35 is driven to cause the boom 30 to be hoisted.

On the other hand, when the boom operating lever 74 is tilted in the left-right direction, the controller 50 switches the spool movement direction of the telescopic control valve V7 according to the tilting direction of the operating lever, and adjusts the valve opening to a predetermined valve opening degree. The boom 30 is telescopically operated by controlling the boom telescoping cylinder 36. The swing operating lever 75 is configured to be tiltable in the left and right directions from the neutral position, and the controller 50 is configured such that when the operating lever is tilted to the right, the workbench 40 moves in the direction of arrow U in FIG. 1(b). The spool movement direction and valve opening degree of the oscillation control valve V8 are controlled counterclockwise in the direction and until the spool is oriented at an angle corresponding to the tilt angle of the operating lever. Further, when the swing operation lever 75 is tilted to the left, the controller 50 causes the workbench 40 to rotate clockwise in the direction of arrow C in FIG. The spool moving direction and valve opening degree of the swing control valve V8 are controlled until the swing control valve V8 faces the specified angle.

Next, details of the control of the steering direction switching valve V3 and the steering angle speed control valve V4 by the steering angle control section 52 will be described in detail with reference to FIGS. 3 and 4. First, with reference to FIG. 3, the hydraulic circuit of the portion related to the operation control of the steering cylinder 66 will be described. In FIG. 3, the steering direction switching valve V3 is a directional switching valve with 4 ports and 3 positions, and the spool position (hereinafter referred to as "normal position") when the steering direction switching valve V3 is not under any control is as follows. All ports are open. At this time, the position of the cylinder rod of the steering cylinder 66 is such that the steering angle of the steered wheels 12 is in the straight-ahead direction (hereinafter also referred to as the "straight-ahead position"). Note that a holding valve (not shown) is provided in each of the two hydraulic paths connecting the steering cylinder 66 and the steering direction switching valve V3, so that the steering direction switching valve V3 is in an all-port open state. Even if this occurs, the cylinder rod of the steering cylinder 66 is configured to maintain its current position (that is, maintain the current steering angle of the steered wheels 12).

In this state, for example, if the steering lever 72 is tilted to the right, the steering angle control unit 52
In the diagram, the solenoid on the left side is energized to move the spool from the normal position to the right, so that the P port (hydraulic oil supply port) and A port are connected, and the B port and T port (hydraulic oil supply port) are connected. (port that returns to the hydraulic oil tank T). Thereby, the hydraulic oil supplied to the P port is output from the A port, and moves the cylinder rod of the steering cylinder 66 in the extending direction. On the other hand, when the steering lever 72 is tilted to the right, the steering angle control unit 52 excites the solenoid on the right side in the figure to move the spool from the normal position to the left, and connects the P port and B Switch to the position where the port is connected, and the A port and T port are connected. Thereby, the hydraulic oil supplied to the P port is output from the B port, and moves the cylinder rod of the steering cylinder 66 in the direction of contraction.

The steering angular speed control valve V4 includes a 2-port, 2-position proportional valve V4a and a 4-port, 2-position pilot switching valve V4b. The normal position of the spool in the proportional valve V4a is a closed state between the hydraulic oil supply port and the output port, and when the steering lever 72 is tilted in either the left or right direction, the steering angle control section 52 By moving the spool to the right in the figure and controlling the opening degree of the valve according to the tilt angle of the travel control lever 71, the flow rate of the hydraulic oil passing through the proportional valve V4a is controlled.

The normal position of the spool in the pilot switching valve V4b is such that the first supply port P1 connected to the output port of the proportional valve V4a communicates with the A port, and the second supply port P1, which is connected to the output port of the proportional valve V4a, communicates with the A port, and the second supply port is supplied with hydraulic oil from the hydraulic pump P. Port P2 and B port are in a closed state. When the spool of the proportional valve V4a is in the normal position, the pilot pressure of the hydraulic oil branched from the path where the hydraulic oil supplied from the hydraulic pump P reaches the second supply port P2 causes the spool to move to the left in the figure. direction, the first supply port P1 and the A port are brought into a closed state, and the second supply port P2 and the B port are brought into communication.

On the other hand, when the spool of the proportional valve V4a moves from the normal position to the right in the figure and hydraulic oil is output from the output port of the proportional valve V4a, the output port of the proportional valve V4a and the pilot switching valve V4b The spool of the pilot switching valve V4b moves to the right in the figure due to the pilot pressure of the hydraulic oil branched from the path between the first supply port P1 and the first supply port P1. Thereby, the first supply port P1 and the A port are communicated, and the second supply port P2 and the B port are in a closed state.

In addition, in the pilot switching valve V4b, when the first supply port P1 and the A port are in a closed state and the second supply port P2 and the B port are in communication, the oil is supplied from the hydraulic pump P. The hydraulic fluid is output to a path for operating other actuators (swivel motor 26, boom hoisting cylinder 35, boom telescoping cylinder 36, and swing motor 46). Furthermore, a two-port, two-position unload valve Vu is provided between the hydraulic path output from the B port of the pilot switching valve V4b and the recirculation path to the hydraulic oil tank T.

When the spool of this unload valve Vu is in the normal position, the supply port and output port are in communication, and the hydraulic oil output from the B port of the pilot switching valve V4b is transferred to the hydraulic oil tank T. It is designed to flow back. Furthermore, when any of the swing operation lever 73, boom operation lever 74, or swing operation lever 75 is tilted, the spool of the pilot switching valve V4b is moved to the left in the figure by the rudder angle control section 52. As a result, passage of hydraulic oil from the first supply port P1 to the A port is blocked, but passage of hydraulic oil from the second supply port P2 to the B port is allowed.

According to the hydraulic circuit shown in FIG. 3, when the steering lever 72 is in the neutral position, if the proportional valve V4a remains open and becomes uncontrollable due to some reason (for example, foreign matter is mixed in), Since the spool of the steering direction switching valve V3 is in the normal position (all ports open), the hydraulic oil supplied from the steering angular velocity control valve V4 flows back to the hydraulic oil tank T as it is. Therefore, even in such a situation, the cylinder rod of the steering cylinder 66 does not change, so the steering angle of the steered wheels 12 does not change even though the steering lever 72 is not operated.

Furthermore, when the steering lever 72 is in the neutral position, for some reason the spool of the steering direction switching valve V3 remains in either the left or right position (i.e., a state in which hydraulic oil can be supplied to the steering cylinder 66) and control becomes impossible. If this happens, the spool of the proportional valve V4a is in the normal position, so the connection between the supply port and the output port of the proportional valve V4a is closed, and the supply from the hydraulic pump P is interrupted. Due to the pilot pressure of the hydraulic oil, the spool of the pilot switching valve V4b moves from the normal position to the left in FIG. The hydraulic oil supplied from the B port to the second supply port P2 flows back to the hydraulic oil tank T from the B port .

Therefore, even if the steering direction switching valve V3 or the proportional valve V4a of the steering angular speed control valve V4 remains open for some reason and becomes uncontrollable when the steering lever 72 is in the neutral position, the steering lever 72 is in the neutral position. The steering angle of No. 12 will not be displaced against the operator's intention.

Next, the details of the control performed by the steering angle control section 52 on the proportional valve V4a of the steering angular velocity control valve V4 when the steering lever 72 is tilted will be described. When the steering lever 72 is tilted rightward or leftward from the neutral position, the steering angle control unit 52 adjusts the running speed of the traveling body 10 (more precisely, an index value (speed) indicating the traveling speed of the traveling body 10). The opening degree of the proportional valve V4a is adjusted according to the index value)), thereby controlling the flow rate of hydraulic oil supplied to the steering direction switching valve V3. As the speed index value of the traveling body 10, for example, a meter may be provided to measure the traveling speed of the traveling body 10, and the speed information output from the meter may be used as the speed index value. However, in this embodiment, the traveling operation lever 71 The inclination angle is used as the speed index value of the traveling object 10.

Hereinafter, the content of control of the proportional valve V4a according to the inclination angle of the travel control lever 71 will be explained with reference to the graph shown in FIG. In the graph shown in FIG. 4, the horizontal axis shows the opening degree (operation amount) of the travel control lever 71, and the vertical axis shows the flow rate (liters per minute (L/min) of hydraulic oil supplied to the steering direction switching valve V3). ) is shown. Moreover, FIG. 4(a) shows the flow rate of hydraulic oil by the proportional valve V4a with respect to the opening degree of the travel operation lever 71 when the travel mode is set to the low speed mode or the medium speed mode. Further, FIG. 4(b) shows the flow rate of hydraulic oil by the proportional valve V4a with respect to the opening degree of the travel operation lever 71 when the travel mode is set to the high-speed mode.

In this embodiment, there are three running modes: a low speed mode, a medium speed mode, and a high speed mode, and the maximum running speed of the running body 10 is limited to the speed corresponding to each running mode. . In this embodiment, the low speed mode is defined as 1.2 km/h, the medium speed mode as 3.0 km/h, and the high speed mode as 7.2 km/h. As a result, the traveling speed of the traveling body 10 increases according to the opening degree of the traveling operation lever 71, and when the opening degree is 100 (%), the traveling speed of the traveling body 10 changes to the set traveling mode. The vehicle is controlled to reach the corresponding maximum travel speed. Note that the driving mode can be changed by a driving mode changeover switch (not shown) provided on the operating device 70.

First, as shown in FIG. 4(a), when the driving mode is set to low speed mode or medium speed mode, the steering angle control unit 52 controls the steering direction switching valve regardless of the opening degree of the driving operation lever 71. Proportional valve V4a is controlled so that the control flow rate for V3 is constant. However, when the steering lever 72 is tilted to the right, the control flow rate is controlled to 17.6 (L/min), and when the steering lever 72 is tilted to the left, the control flow rate is controlled to 12.6 (L/min). L/min). This is to ensure that when a single rod cylinder is used as the steering cylinder 66, the displacement speed of the steering wheel 12 is the same when the steering angle is displaced to the right and when it is displaced to the left. .

That is, due to the structure of the single-rod cylinder, the volume of hydraulic oil required to move the cylinder rod the same distance is different depending on whether the cylinder rod is extended from the neutral position or when it is retracted. Specifically, more hydraulic oil is required when the cylinder rod is extended than when it is retracted. In this embodiment, when the steering lever 72 is tilted to the right, the steering cylinder 66 is extended, thereby displacing the steering angle of the steered wheels 12 to the left with respect to the forward direction (see FIG. 1(a)). Therefore, the traveling body 10 turns to the right when moving forward. On the other hand, when the steering lever 72 is tilted to the left, the steering cylinder 66 contracts, which causes the steering angle of the steered wheels 12 to shift to the right with respect to the forward direction. It will turn left. Therefore, when the steering lever 72 is tilted to the right than when the steering lever 72 is tilted to the left, hydraulic oil is supplied to the steering direction switching valve V3 (and by extension to the steering cylinder 66) at a faster flow rate. This allows the displacement speed of the steering angle of the steered wheels 12 to be matched in the left-right direction. This makes it possible to eliminate the difference in time required for the steering angle to reach a predetermined angle due to a difference in the steering direction, thereby improving the operability of the traveling body 10.

Next, when the travel mode is set to the high speed mode, the steering angle control section 52 changes the flow rate of hydraulic oil supplied to the steering direction switching valve V3 according to the opening degree of the travel operation lever 71. Specifically, as shown in the graph of FIG. 4(b), when the travel control lever 71 is in the range of 0% to 20%, the proportional valve is controlled so that the control flow rate is the same as in the low speed mode and the medium speed mode. Controls the opening degree of V4a. That is, when the steering lever 72 is tilted to the right, the control flow rate is set to 17.6 (L/min), and when the steering lever 72 is tilted to the left, the control flow rate is set to 12.6 (L/min). /min).

Then, when the opening degree of the travel control lever 71 is in the range of 20% to 80%, the opening degree of the proportional valve V4a is corrected so that the control flow rate gradually decreases according to the opening degree. Specifically, when the steering lever 72 is tilted to the right, the control flow rate is within the range of 17.6 to 11.2 (L/min), and when the steering lever 72 is tilted to the left. If the control flow rate is within the range of 12.6 to 6.2 (L/min), the control flow rate is adjusted according to the opening degree of the travel control lever 71 as shown in the graph of FIG. 4(b). , controls the opening degree of the proportional valve V4a.

Furthermore, when the travel control lever 71 is in the range of 80% to 100% opening and the steering lever 72 is tilted to the right, the controlled flow rate is kept constant at 11.2 (L/min). The opening degree of the proportional valve V4a is controlled so that when the steering lever 72 is tilted to the left, the controlled flow rate is constant at 6.2 (L/min). .

In this way, when the steering angle control unit 52 is set to the high-speed mode, the operating speed of the steering wheel 12 is corrected to become slower as the traveling speed of the traveling object 10 increases, so that the steering lever 72 is The course change of the traveling body 10 can be suppressed from reacting too sensitively to the operation, and as a result, the operability of the traveling body 10 can be improved. However, when the opening degree of the travel control lever 71 is within the range of 0% to 20%, the traveling body 10 is traveling at a low speed, and there is no risk of the traveling body responding too sensitively to a change in course. Therefore, the above-mentioned correction for the operating speed of the steered wheels 12 is not performed.

Note that the present invention is not limited to the above embodiments, and can be modified as appropriate without departing from the gist of the present invention. For example, in the present embodiment, actuators that use hydraulic pressure as a drive source, such as the travel motor 16, the steering cylinder 66, and the brake cylinder 18, are used as travel drive actuators for controlling the travel of the travel object 10. However, the present invention is not limited to this, and various actuators such as electric motors and internal combustion engines may be used. Further, in this embodiment, the steering operation is performed using the steering lever 72, but the steering operation may be performed using a steering dial. Furthermore, in the above-described embodiments, an example is given of an aerial work vehicle equipped with a telescoping boom capable of raising and lowering, extending and contracting, and turning. Good too.

1 Aerial work vehicle 10 Traveling body 12 Steering wheel 20 Swivel body 30 Boom 40 Work platform 50 Controller 52 Rudder angle control section (speed index value detection device, steering actuator control device)
66 Steering cylinder (steering actuator)
70 Operation device 71 Travel operation lever (travel operation device)
72 Steering lever (steering operation device)

Claims (4)

A running body equipped with a steering wheel and capable of running;
a rotating body rotatably provided on the traveling body;
a boom provided on the revolving body such that it can be raised and lowered;
a work platform provided at the tip of the boom on which a worker can board;
a steering operation device provided on the workbench and operated by a worker on the workbench;
a steering actuator that performs a steering operation of the steering wheel;
A travel control device for an aerial work vehicle, comprising: a steering actuator control device that controls the operation of the steering actuator in accordance with an operation of the steering operation device;
comprising a speed index value detection device for detecting a speed index value indicating the traveling speed of the traveling object,
The steering actuator control device corrects the operating speed of the steering actuator in response to the operation of the steering operation device so that it becomes slower as the speed index value detected by the speed index value detection device increases. A travel control device for an aerial work vehicle characterized by: The steering actuator control device is configured not to correct the operating speed of the steering actuator according to the operation of the steering operation device when the speed index value detected by the speed index value detection device is less than a predetermined value. The travel control device for a vehicle for working at high altitudes according to claim 1. The steering actuator control device controls the operating speed of the steering actuator to be an operating speed corresponding to the speed index value detected by the speed index value detection device while the steering operation device is being operated . The traveling control device for an aerial work vehicle according to claim 1 . a traveling operation device provided on the workbench and operated by a worker on the workbench;
a traveling speed control device that controls the traveling speed of the traveling body according to the operation of the traveling operation device,
The travel control device for a vehicle for aerial work according to any one of claims 1 to 3 , wherein the speed index value detection device detects the speed index value based on an operation of the travel operation device.

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