JP2009078812A - Swing control device for industrial vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To regulate or allow swing of a frame in accordance with a vehicle state to maintain the stable posture of a vehicle, in the industrial vehicle in which the frame is swingably supported with respect to a rear axle. <P>SOLUTION: In this swing control device, the frame 1 is swingably supported with respect to the rear axle 9 around a support pin 10. A hydraulic cylinder 13 is interposed between one end part of the rear axle 9 and the frame 1, and a solenoid selector valve 18, an accumulator 19 and pressure sensors 20, 21 are provided on oil passages 16, 17 connecting an upper chamber 13a to a lower chamber 13b of the hydraulic cylinder 13. The swing control device is provided with a controller 22 for operating and switching the solenoid selector valve 18 to a shutoff position 18a or a communication position 18b in accordance with change in a swing angle of the frame 1 and change in pressure of the upper and lower chambers 13a, 13b of the hydraulic cylinder 13 to regulate and allow the swing of the frame 1 in both of clockwise and counterclockwise directions. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a swing control device for an industrial vehicle, and more particularly to a swing control device that restricts or allows swinging of a frame relative to a rear axle in an industrial vehicle such as a forklift.

  An example of this type of industrial vehicle is a forklift. FIG. 13 shows an outline of a general forklift. In this figure, 1 is a frame, 2 is a mast that is erected on the front side of the frame 1 so as to be pivotable in the front-rear direction, 3 is a fork for cargo handling that rises and falls along the mast 2, and 4 is a lift fork. The lift cylinder 5 is a tilt cylinder that tilts the mast 2 back and forth. Reference numeral 6 denotes a front wheel which is a traveling drive wheel of the forklift, 7 denotes a rear wheel which is a steering wheel, and 8 denotes a steering handle of the forklift.

  14 and 15 show a conventional forklift swinging device, wherein 9 is a rear axle on which the left and right rear wheels 7 and 7 are mounted, and 10 is provided on both front and rear sides of a substantially central portion in the longitudinal direction of the rear axle 9. The support pins 11 are support supports for holding the support pins 10 and 10 on the frame 1. Reference numeral 12 denotes a stopper fixed on both sides of the lower surface of the frame 1, and is provided so as to have a predetermined gap from the upper surface of the rear axle 9 in a normal traveling state. The frame 1 can swing with respect to the rear axle 9 until it comes into contact with the upper surface of the rear axle 9.

  Thus, even when the road surface on which the forklift travels is uneven or the road surface is inclined, the frame 1 swings left and right around the support pin 10 of the rear axle 9, so that the front The wheel 6 and the rear wheel 7 can touch the road surface and travel stably.

  As described above, the conventional forklift is configured such that the frame can swing with respect to the rear axle. However, when the forklift turns, centrifugal force and inertial force act on the vehicle, and the lateral force is the center between the front wheels. As shown in FIG. 16, the frame swings with respect to the rear axle, and the front wheel on the turning center side rises from the road surface, as shown in FIG. The posture may become unstable.

  Also, in high load handling work, lateral force acts on the vehicle due to the shift of the center of gravity of the load to the left and right, the backlash and deflection of the mast, and so on. May swing and the front wheel on the side opposite to the side to which the lateral force is applied may float from the road surface and the vehicle posture may become unstable.

  On the other hand, a device for restricting the swing of the frame has been proposed (for example, Japanese Patent Laid-Open No. 10-58935). However, since the road surface on which an industrial vehicle such as a forklift travels is not necessarily flat, the frame is horizontal. However, if the frame is restricted from swinging when the rear axle is swinging significantly due to unevenness or inclination of the road surface, when the road surface in contact with the rear axle returns to the horizontal position, In the opposite case, the frame is fixed while being oscillated in the lateral direction, and the posture of the vehicle becomes unstable compared to an industrial vehicle that is not equipped with a device that restricts oscillating.

  Therefore, in an industrial vehicle in which the frame is supported so as to be able to swing with respect to the rear axle, a solution is made to hold or stabilize the posture of the vehicle by restricting or allowing the frame to swing according to the state of the vehicle. The technical problem which should arise arises, and this invention aims at solving this subject.

The present invention has been proposed in order to achieve the above object, and the invention according to claim 1 is directed to an industrial vehicle in which a frame is swingably supported at a substantially central portion of a rear axle. A hydraulic cylinder is interposed between the end and the frame, and an electromagnetic switching valve that switches between connection and disconnection of the hydraulic oil in an oil passage connecting the upper chamber and the lower chamber of the hydraulic cylinder, and supply and discharge of the hydraulic oil And an accumulator for detecting the swing load of the hydraulic cylinder, and switching the electromagnetic switching valve according to the swing angle of the frame and the swing load of the hydraulic cylinder to thereby swing the frame. Provided is a swing control device for an industrial vehicle, which is provided with a control means that can be regulated and that has a control means that allows return to the opposite side even when the swing of the frame is restricted.
According to a second aspect of the present invention, when the frame swings over a certain amount with respect to the rear axle and is in a swing restricting state, the hydraulic cylinder is caused by a pressure difference between the upper chamber and the lower chamber of the hydraulic cylinder. The invention according to claim 1, further comprising a control means for detecting the load direction of the sway and temporarily canceling the swing restriction state when a load is applied in a direction returning to the horizontal state. It is.

  According to the first aspect of the present invention, a hydraulic cylinder is interposed between a frame swingable with respect to the rear axle and one end of the rear axle, and an oil passage connecting the upper chamber and the lower chamber of the hydraulic cylinder is provided. An electromagnetic switching valve, an accumulator, and a means for detecting the swing load of the hydraulic cylinder are provided, and the switching of the electromagnetic switch valve is controlled according to the swing angle of the frame and the swing load of the hydraulic cylinder, thereby restricting the swing of the frame. Or, because it is configured to allow, when the frame swings more than a certain amount with respect to the rear axle, it will be in the “bidirectional regulation” operation mode, and further the state where the frame is about to return to the horizontal state from the state where it swings greatly While detecting this, the posture of the vehicle can be stabilized by releasing the “bidirectional restriction” and allowing the swing. In other words, the load direction of the hydraulic cylinder is detected based on the pressure difference between the upper chamber and the lower chamber of the hydraulic cylinder, and when the load is applied to the safe side, the swing regulation is canceled to stabilize the vehicle.

  Further, the invention according to claim 2 measures the cylinder upper and lower chamber pressures during the cargo handling restriction operation and the travel restriction operation, and detects the load direction of the hydraulic cylinder by the differential pressure between the upper and lower chamber pressures. Since the swing restriction state is temporarily released when a load is applied in the direction returning to the horizontal state, the posture of the vehicle can be stabilized.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows the rocking | fluctuation control apparatus of Embodiment 1 of this invention. Explanatory drawing which shows the rocking | fluctuation control apparatus of Embodiment 2 of this invention. Explanatory drawing which shows the rocking | fluctuation control apparatus relevant to this invention. The top view of the rear axle which shows the assembly structure of a steering angle sensor. The longitudinal cross-sectional view of the rear axle of the kingpin part which shows the assembly structure of a steering angle sensor. (A) The front view which shows the assembly structure of a rocking angle sensor. (B) The side view which shows the assembly structure of a rocking angle sensor. The map figure which shows the necessity judgment of the rocking | fluctuation control with respect to a lifting height and a loading load. The map figure which shows the necessity judgment of the rocking | fluctuation control with respect to a running speed and a steering angle. The map figure which shows the necessity judgment of the rocking | fluctuation control with respect to driving speed and steering angular velocity. The map figure which shows rocking | fluctuation regulation with respect to the rocking | swiveling angle and pressure difference in Embodiment 1 and Embodiment 2, and cancellation | release of restriction | limiting. (A) thru | or (c) are explanatory drawings regarding the rocking | fluctuation and restriction | limiting of a flame | frame. The map figure which shows the operation | movement mode of the rocking angle and rocking | fluctuation regulation shown in FIG. The side view which shows the outline | summary of the general forklift which is an example of an industrial vehicle. The front view of the rear axle which shows the rocking device of the conventional forklift. The longitudinal side view of the rear axle which shows the rocking device of the conventional forklift. The rear view of the forklift truck which shows the state which the frame rock | fluctuated.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The swing control device for a forklift will be described as an example of an industrial vehicle. However, the outline of the forklift is the same as that shown in FIG. 13, and therefore the description thereof will be omitted. Use the same symbols.

  FIG. 1 shows Embodiment 1 of the present invention, in which 13 is a double rod type hydraulic cylinder, and the rod side of the hydraulic cylinder 13 is fixed to either the left or right end of the rear axle 9. The head of the hydraulic cylinder 13 is supported by a bracket 15 fixed on the lower surface of the frame 1. In the middle of an oil passage 16 communicating with the upper chamber 13a of the hydraulic cylinder 13 and an oil passage 17 communicating with the lower chamber 13b, an electromagnetic switching valve 18 at a 3-port 2 position is provided, and hydraulic oil is provided in the oil passage 16 and the oil passage 17. An accumulator 19 for supplying / discharging is disposed. When the hydraulic oil leaks from the hydraulic circuit, the oil in the accumulator 19 is supplied to the oil passages 16 and 17, and when the hydraulic oil in the hydraulic circuit thermally expands, the oil is absorbed by the accumulator 19. A pressure sensor 20 is provided in the oil passage 16 as means for detecting the pressure in the upper chamber 13a of the hydraulic cylinder 13, and a pressure sensor 21 is provided in the oil passage 17 as means for detecting the pressure in the lower chamber 13b. The detection signals of these pressure sensors 20, 21 are input to the controller 22, and the pressures in the upper chamber 13a and the lower chamber 13b are calculated.

  Here, when the solenoid 23 of the electromagnetic switching valve 18 is excited by the current from the controller 22, the electromagnetic switching valve 18 is switched from the cutoff position 18a to the communication position 18b. Accordingly, the hydraulic oil in the upper chamber 13a and the lower chamber 13b flows in and out of the hydraulic cylinder 13 and the hydraulic cylinder 13 can be expanded and contracted, and the accumulator 19 communicates with the oil passages 16 and 17 so that the hydraulic oil is accumulated in the accumulator 19. Will be supplied and discharged. In this case, the frame 1 can be swung in the left-right direction with respect to the rear axle 9, that is, in both the clockwise and counterclockwise directions around the support pin 10 (hereinafter, this operation mode is changed). This is called “deregulation”.

  On the other hand, when the current from the controller 22 is stopped and the solenoid 23 is de-energized, the electromagnetic switching valve 18 is switched to the cutoff position 18a. Accordingly, the hydraulic oil in the upper chamber 13a and the lower chamber 13b of the hydraulic cylinder 13 cannot flow in and out, and the hydraulic cylinder 13 cannot be expanded or contracted. In such a case, the swinging of the frame 1 in both the clockwise and counterclockwise directions with respect to the rear axle 9 is restricted (hereinafter, this operation mode is referred to as “bidirectional restriction”).

  Here, the sensors other than the pressure sensors 20 and 21 will be described. As a means for detecting the swing angle of the frame 1 with respect to the rear axle 9, a swing angle sensor 24 is provided above the support support 11, and the vehicle As means for detecting the steering angle, a steering angle sensor 26 is provided on the king pin 25 of the rear axle 9. Reference numeral 27 denotes a speed sensor attached to a speed reduction mechanism (not shown) such as a transmission or a differential gear in order to detect the traveling speed of the vehicle. Reference numeral 28 denotes a hydraulic circuit such as a lift cylinder 4 to detect a load. A load sensor 29 is provided (not shown), and 29 is a lift sensor attached to the mast 2 in order to detect the lift of the loaded load.

  FIG. 2 shows a second embodiment of the present invention, and the same components as those of the first embodiment shown in FIG. In the drawing, reference numeral 31 denotes a single rod type hydraulic cylinder, and the rod side of the hydraulic cylinder 31 is supported by a bracket 14 fixed to either the left or right end of the rear axle 9, and the hydraulic cylinder 31 The head side is supported by a bracket 15 fixed on the lower surface of the frame 1. In the middle of the oil passage 16 communicating with the upper chamber 31a of the hydraulic cylinder 31 and the oil passage 17 communicating with the lower chamber 31b, electromagnetic switching valves 32 and 33 at two ports and two positions are provided in series. An accumulator 19 is disposed between When the hydraulic oil leaks from the hydraulic circuit, the oil in the accumulator 19 is supplied to the oil passages 16 and 17, and when the hydraulic oil in the hydraulic circuit thermally expands, the oil is absorbed into the accumulator 19 and the hydraulic cylinder. The function is to supply and discharge the differential volume of 31 rods.

  When the solenoid 34 of one electromagnetic switching valve 32 is excited by the current from the controller 22, the electromagnetic switching valve 32 is switched from the cutoff position 32a to the communication position 32b, and the solenoid 35 of the other electromagnetic switching valve 33 is switched to the controller 22. When excited by the current from the electromagnetic switching valve 33, the electromagnetic switching valve 33 is switched from the cutoff position 33a to the communication position 33b. Therefore, when both the electromagnetic switching valves 32 and 33 are switched to the communication positions 32b and 33b, the hydraulic oil in the upper chamber 31a and the lower chamber 31b of the hydraulic cylinder 31 flows in and out, so that the hydraulic cylinder 31 can be expanded and contracted. At the same time, the accumulator 19 communicates with the oil passages 16 and 17, and hydraulic oil is supplied to and discharged from the accumulator 19. In this case, the operation mode of “restriction release” in which the frame 1 can swing clockwise and counterclockwise with respect to the rear axle 9 is set.

  On the other hand, when the solenoids 34 and 35 are de-excited by the current from the controller 22, the electromagnetic switching valves 32 and 33 are switched to the cutoff positions 32a and 33a, respectively. Therefore, the hydraulic oil in the upper chamber 31a and the lower chamber 31b of the hydraulic cylinder 31 cannot flow in and out, and the hydraulic cylinder 31 cannot be expanded or contracted. In such a case, the operation mode of “bidirectional regulation” in which the swing of the frame 1 with respect to the rear axle 9 is regulated.

  Although FIG. 3 does not correspond to the embodiment of the present invention, it will be described at the same time because it relates to the present invention. In addition, about the same component as Embodiment 1 shown in FIG. 1 and Embodiment 2 shown in FIG. 2, the same code | symbol is attached | subjected and the description is abbreviate | omitted. In the figure, reference numeral 13 denotes a double rod type hydraulic cylinder, which is located in the middle of an oil passage 16 communicating with the upper chamber 13a of the hydraulic cylinder 13 and an oil passage 17 communicating with the lower chamber 13b at the position of the 2 port 2 position. An electromagnetic switching valve 36 is provided, and an accumulator 19 for supplying and discharging hydraulic oil to and from the oil passage 16 and the oil passage 17 is disposed in parallel with the electromagnetic switching valve 36. Reference numerals 38 and 39 denote throttle valves provided between the accumulator 19 and the upper chamber 13a or the lower chamber 13b of the hydraulic cylinder 13. The throttle valves 38 and 39 are not shut off, but are almost in a closed state. The oil is throttled so that the hydraulic oil is supplied from the accumulator 19 when oil leaks, and the hydraulic oil can be discharged to the accumulator 19 when the hydraulic oil expands.

  When the solenoid 37 of the electromagnetic switching valve 36 is excited by a signal from the controller 22, the electromagnetic switching valve 36 is switched from the cutoff position 36a to the communication position 36b. Accordingly, the hydraulic oil in the upper chamber 13a and the lower chamber 13b flows in and out of the hydraulic cylinder 13, and the hydraulic cylinder 13 can be expanded and contracted. In this case, the operation mode of “restriction release” in which the frame 1 can swing clockwise and counterclockwise with respect to the rear axle 9 is set.

  On the other hand, when there is no signal from the controller 22 and the solenoid 37 is de-energized, the electromagnetic switching valve 36 is switched to the cutoff position 36a. Accordingly, the hydraulic oil in the upper chamber 13a and the lower chamber 13b of the hydraulic cylinder 13 cannot flow in and out, and the hydraulic cylinder 13 cannot be expanded or contracted. In such a case, the operation mode of “bidirectional regulation” in which the swing of the frame 1 with respect to the rear axle 9 is regulated.

  Next, the assembly structure of the steering angle sensor 26 will be described with reference to FIGS. A bell crank 40 is pivotally attached to the center portion of the rear axle 9, brackets 41, 41 are provided at both ends of the rear axle 9, and a knuckle arm 42 for supporting the rear wheels 7, 7 on the brackets 41, 41. , 42 are attached. A king pin 25 is fixed to the knuckle arm 42, and an upper end portion and a lower end portion of the king pin 25 are rotatably supported on the rear axle 9 via bearings 43 and 43. The bell crank 40 is connected to the knuckle arms 42 and 42 via a pair of left and right tie rods 44 and 44. When the steering wheel 8 is operated, the bell crank 40 rotates around the bell crank pin 45 and the tie rods 44, 44 are pushed and pulled in the left-right direction, so that the knuckle arms 42, 42 rotate around the king pins 25, 25. The rear wheels 7 and 7 are steered. The steering angle sensor 26 is attached to either the left or right king pin 25. Thus, when the rear wheels 7 and 7 are steered by operating the steering handle 8, the rotation of the kingpin 25 is transmitted to the steering angle sensor 26, and the rotational displacement of the kingpin 25 is discriminated by the controller 22 to determine the steering angle. Is calculated.

  FIG. 6 shows an assembly structure of the swing angle sensor 24. The swing angle sensor 24 includes a cylindrical main body 24a, a mounting flange 24b provided at the end of the main body 24a, and a horizontal position from the mounting flange 24b. The input plate 24c protrudes, and a link plate 50 is fixed to the tip of the input shaft 24c. A guide hole 51 is formed in the tip of the link plate 50 along the longitudinal direction. The swing angle sensor 24 is bolted to the frame 1 by the mounting flange 24b. On the other hand, an inverted L-shaped arm 52 is erected on the rear axle 9, and a pin 53 is projected from the tip of the arm 52 toward the swing angle sensor 24, and the pin 53 is a guide hole of the link plate 50. 51 is inserted.

  As shown by a two-dot chain line in FIG. 2A, when the frame 1 swings clockwise around the support pin 10 with respect to the rear axle 9, the position of the swing angle sensor 24 is the upper right in the figure. Since the pin 53 of the arm 52 is engaged with the guide hole 51 of the link plate 50, the link plate 50 and the input shaft 24c rotate counterclockwise with respect to the swing angle sensor 24. To do. Therefore, a change in the detection signal of the swing angle sensor 24 is input to the controller 22 and the swing direction and swing angle of the frame 1 with respect to the rear axle 9 (in other words, the swing direction of the rear axle 9 with respect to the frame 1 and Oscillating angle) is calculated.

  In this way, the swing angle sensor 24 is located away from the support pin 10 that is the swing center of the rear axle 9, and the support pin 10, the input shaft 24c of the swing angle sensor 24, and the link plate 50. By installing the guide hole 51 and the pin 53 of the arm 52 in a straight line, the rotation angle of the swing angle sensor 24 is amplified, and an accurate swing angle can be detected by an inexpensive sensor. it can. Even if the swing angle of the rear axle 9 is ± 3 °, for example, the rotation angle of the pin 53 with respect to the input shaft 24c of the swing angle sensor 24 is amplified to ± 45 °, for example. The swing angle can be accurately detected with a general sensor without using the. Further, since the support pin 10, the input shaft 24c of the swing angle sensor 24, the guide hole 51 of the link plate 50, and the pin 53 of the arm 52 are installed in a straight line, the clockwise direction and the counterclockwise direction are provided. The rotation angle of the rocking angle sensor 24 becomes symmetrical, and the positive and negative values of the rocking angle are the same, so that the determination is easy.

  Further, since no linkage is used, there are few errors, adjustment of the linkage is unnecessary, the number of assembly steps can be reduced by reducing the number of parts, and an accurate swing angle can be detected with a simple and inexpensive configuration. In assembly, the swing angle sensor 24 is attached to the frame 1 and the arm 52 with the pin 53 is attached to the rear axle 9, so that the swing angle can be accurately detected with a very simple structure. is there.

  Thus, the controller 22 initializes the failure flag f when the control system is started up, and the pressure sensors 20 and 21, the swing angle sensor 24, the steering angle sensor 26, the speed sensor 27, the load sensor 28, and the lift height sensor 29. A detection signal is read, and whether or not there is a failure is determined by verifying whether or not the input value from each sensor is a value generated at the time of failure, disconnection or short circuit.

  Here, in the first embodiment shown in FIG. 1 and the second embodiment shown in FIG. 2, when the pressure sensors 20, 21 are normal, the pressures of the oil passage 16 and the oil passage 17 are determined from the respective input values. And the pressure difference between the upper chamber 13a and the lower chamber 13b of the hydraulic cylinder 13 or the pressure difference between the upper chamber 31a and the lower chamber 31b of the hydraulic cylinder 31 is calculated. This pressure difference p is a pressure difference obtained by subtracting the pressure in the lower chamber from the pressure in the upper chamber. When the input values from the pressure sensors 20 and 21 are values such as failure or disconnection, “0” is input to the pressure difference p, and “failure of the pressure sensor 20 (or 21)” is input to the failure flag f.

  When the swing angle sensor 24 is normal, the swing angle y of the frame 1 with respect to the rear axle 9 is calculated from the input value. The swing angle y is a positive value when the frame 1 swings clockwise. When the input value from the swing angle sensor 24 is a value such as failure or disconnection, “error” is input to the swing angle y, and “failure of the swing angle sensor 24” is input to the failure flag f.

  When the steering angle sensor 26 is normal, the steering angle r, the steering direction d, and the steering angular velocity dr are calculated from the input values. The steering angle r here is not the turning angle of the kingpin 25 but the absolute value of the actual steering angle of the vehicle, and the steering angular velocity dr is the rate of change of the actual steering angle with respect to time. When the input value from the steering angle sensor 26 is a value such as failure or disconnection, the “maximum steering angle” is input to the steering angle r, the “error” is input to the steering direction d, and the steering angular velocity dr is set. “Maximum steering angular velocity” is input, and “failure of the steering angle sensor 26” is input to the failure flag f.

  Similarly, when the speed sensor 27 is normal, the traveling speed v of the vehicle is calculated from the input value. When the input value from the speed sensor 27 is a value such as failure or disconnection, “maximum speed” is input to the traveling speed v, and “failure of the speed sensor 27” is input to the failure flag f. Further, when the load sensor 28 is normal, the loaded load w is calculated from the input value. When the input value from the load sensor 28 is a value such as failure or disconnection, “maximum load” is input as the loaded load w, and “failure of the load sensor 28” is input as the failure flag f.

  Further, when the lift height sensor 29 is normal, the lift height h of the loaded load is calculated from the input value. When the input value from the lift sensor 29 is a value such as failure or disconnection, “highest value” is input to the lift height h, and “failure of the lift sensor 29” is input to the failure flag f. For example, if three lift sensors, low lift, medium lift and high lift, are installed, a. Lifting height below the low lifting height, b. Elevation from low to medium height, c. Elevation from mid-high to high It is possible to output higher and higher lifts and four levels of lift. However, if the middle lift sensor fails, the lift is less than the lower lift, the lift from the lower lift to the higher lift, Outputs higher and higher lifts and three levels of lift.

  Moreover, the controller 22 investigates the failure of each solenoid 23, 34, 35, 37 by verifying the energization state of the solenoids 23, 34, 35, and 37 of each electromagnetic switching valve. When any of the solenoids is faulty, “Solenoid 24 (or 34, 35, 37) is faulty” is input to the fault flag f. When a faulty sensor or solenoid is input to the fault flag f, a fault lamp (not shown) provided on the instrument panel is turned on, and a fault location is indicated on the LED or LCD (both not shown). Is displayed.

Next, a control method for restricting or allowing the swing of the frame 1 with respect to the rear axle 9 by the swing control device of the present invention will be described. The controller 22 detects the lifting height h and the loading load w during the cargo handling operation, and as shown in FIG. 7, in which area of the preset map the intersection of the lifting height h and the loading load w exists. To detect. For example, when the intersection of the lift height h and the loaded load w is within the A1 region, it is determined that the swing restriction is not necessary, and “release” is input to the cargo handling restriction flag f _n . On the other hand, when the intersection of the lift height h and the loaded load w is within the A3 region, it is determined that the swing restriction is necessary, and “restriction” is input to the cargo handling restriction flag f _n . The A2 area is a hysteresis area provided to prevent frequent repetition of “restriction” and “cancellation”. When entering the A2 area from the A1 area or the A3 area, the cargo handling restriction flag up to that point is entered. Hold f _n .

  In addition, the controller 22 determines a necessity of swing regulation in the traveling state, and a plurality of maps set in advance based on the lifting height h and the load w, for example, the traveling speed v and the steering as shown in FIG. A map showing the relationship between the angle r and a map showing the relationship between the running speed v and the steering angular speed dr as shown in FIG. 9 are set. The steering angular velocity dr detected by the steering angle sensor 26 is compared with the steering direction d. When the steering angular velocity dr is a value that decreases the steering angle r, 0 is input to the steering angular velocity dr, and the steering angular velocity dr Is a numerical value that increases the steering angle r, the detected value of the steering angular velocity dr is replaced with an absolute value.

For example, when the intersection of the traveling speed v and the steering angle r is within the region B1 in FIG. 8, it is determined that the swing restriction is not necessary, and “release” is input to the travel restriction flag f _S1 . On the other hand, when the intersection of the travel speed v and the steering angle r is within the B3 region, it is determined that the swing restriction is necessary, and “restriction” is input to the travel restriction flag f _S1 . On the other hand, when the intersection of the traveling speed v and the steering angular speed dr is within the region C1 in FIG. 9, it is determined that the swing restriction is not necessary, and “release” is input to the travel restriction flag f _S2 . On the other hand, when the intersection of the travel speed v and the steering angular speed dr is within the C3 region, it is determined that the swing restriction is necessary, and “restriction” is input to the travel restriction flag f _S2 . The B2 region and the C2 region are hysteresis regions provided to prevent frequent repetition of “regulation” and “cancellation”, and when entering the B2 region from the B1 region or the B3 region, or C1 When entering the C2 area from the area or the C3 area, the cargo handling restriction flag f _S1 or f _S2 is held.

In the first embodiment shown in FIG. 1 and the second embodiment shown in FIG. 2, the controller 22 travels when both the travel restriction flags f _S1 and f _S2 are “released”. enter the "release" in the regulation flag f _S, otherwise enter the "regulation" in the driving restriction flag f _S. Further, the swing control based on the cargo handling restriction flag f _{n in which} the swing direction of the frame 1 is unclear is preferentially processed rather than the swing control based on the travel restriction flag f _S. That is, when both the cargo handling restriction flag f _n and the travel regulation flag f _S are “restricted”, the operation mode determined from the cargo handling restriction flag f _n is prioritized. However, when “error” is input to the swing angle y, the operation mode based on the cargo handling restriction flag f _n is not adopted, and the swing control is performed using only the operation mode based on the travel restriction flag f _S.

Thus, when the cargo handling restriction flag f _n is set to “restricted”, the swing of the frame 1 is restricted in the “bidirectional restriction” operation mode. When the controller 22 is functioning “bidirectional regulation”, as shown in FIG. 10, the swing angle y swings large by y5 or more and the pressure difference p between the pressure sensors 20 and 21 increases by p1 or more. Alternatively, as long as the swing angle y swings smaller than −y5 and the pressure difference p between the pressure sensors 20 and 21 becomes smaller than −p1, the operation mode is changed to “restriction release” and the frame 1 swings. Allow movement.

  For example, as shown in FIG. 11 (a), even if the frame 1 is horizontal, if the rear axle 9 swings to the right due to unevenness or an inclined surface of the road surface, the swing angle y becomes a negative value. At the same time, the pressure in the upper chamber 13a becomes larger than the pressure in the lower chamber 13b as the hydraulic cylinder 13 tends to contract, and the pressure difference p increases in the positive direction. .

  In such a state, as shown in FIG. 5B, when the road surface is horizontal or reversely inclined, the rear axle 9 is restricted while the frame 1 is swung counterclockwise. On the contrary, the posture of the vehicle becomes unstable. At that time, the pressure of the upper chamber 13a becomes smaller than the pressure of the lower chamber 13b as the hydraulic cylinder 13 tries to extend due to the horizontal restoring force of the frame 1, and the pressure difference p increases in the negative direction. While the swing angle y of the frame 1 is smaller than −y5 and the state in which the frame 1 is returning to the horizontal direction is detected (when the pressure difference p is smaller than −p1), the operation mode is set to “ Change to “Release Regulation”.

  Therefore, the swing of the frame 1 with respect to the rear axle 9 is allowed, and the posture of the vehicle is stabilized as shown in FIG. It should be noted that when the rear axle 9 swings downward to the left with respect to the frame 1, regulation is performed in contrast to the case where the rear axle 9 swings downward to the right.

On the other hand, when the cargo handling restriction flag f _n is set to “release” or the swing angle y is “error”, the operation mode is determined based on the travel restriction flag f _S. When the travel restriction flag f _S is set to “cancel”, the operation mode is “restriction release”, and when the travel restriction flag f _S is set to “restriction”, the operation mode is “bidirectional restriction”. Regulate rocking. When the “bidirectional regulation” is functioning, the controller 22 is configured such that the swing angle y is smaller than −y5 and the pressure of the pressure sensors 20 and 21 when the vehicle turns right and as shown in FIG. While the difference p is smaller than −p1, the operation mode is changed to “restriction release” to allow the frame 1 to swing.

  On the other hand, the controller 22 oscillates when the vehicle turns counterclockwise while the “bidirectional regulation” is functioning, and as shown in FIG. When the pressure difference p between the pressure sensors 20 and 21 becomes larger than p1, the operation mode is changed to “restriction release” and the frame 1 is allowed to swing.

  Further, when the “bidirectional regulation” is functioning and the vehicle goes straight, and as shown in FIG. 10, the swing angle y swings smaller than −y5 and the pressure difference between the pressure sensors 20, 21 While p is smaller than -p1, or while the rocking angle y is swung more than y5 in the clockwise direction and the pressure difference p between the pressure sensors 20, 21 is larger than p1, the operation mode is set to “regulation”. Change to “Release” to allow the frame 1 to swing.

  Thus, in the first and second embodiments, when the frame 1 swings more than a certain amount with respect to the rear axle 9 and enters the “bidirectional regulation” operation mode, the frame 1 swings greatly. While detecting the state of returning to the horizontal state from the above state, the posture of the vehicle can be stabilized by releasing the “bidirectional restriction” and allowing the swing. That is, the load direction of the hydraulic cylinder 13 or 31 is detected by the pressure sensors 20 and 21, and when a load is applied on the safe side, the swing regulation is canceled to stabilize the vehicle.

In the swing restricting device related to the present invention shown in FIG. 3, the controller 22 determines that the travel restricting flag f is when both the travel restricting flags f _S1 and f _S2 are “released”. “Release” is input to _S. Otherwise, “restriction” is input to the travel restriction flag f _S. Further, the swing control based on the cargo handling restriction flag f _{n in which} the swing direction of the frame 1 is unclear is preferentially processed rather than the swing control based on the travel restriction flag f _S. That is, when both the cargo handling restriction flag f _n and the travel regulation flag f _S are “restricted”, the operation mode determined from the cargo handling restriction flag f _n is prioritized. However, when “error” is input to the swing angle y, the operation mode based on the cargo handling restriction flag f _n is not adopted, and the swing control is performed using only the operation mode based on the travel restriction flag f _S.

Thus, when the cargo handling restriction flag f _n is set to “restrict”, the operation mode of the swing control is determined by the detected value of the swing angle y as shown in FIG. When the swing angle y is swinging more than y2 in the clockwise direction, the “restriction” operation mode is set. When the swing angle y is from 0 to y1, swing is controlled by the “bidirectional control” operation mode. To do. When the swing angle y is between y1 and y2, the previous operation mode is maintained. When the swing angle y swings counterclockwise, regulation is performed in contrast to the case where the swing angle y swings clockwise. Note that the controller 22 when the running restriction flag f _S is set to "cancel" is an operating mode "deregulation", when the running restriction flag f _S is set to "regulation" is the operating mode ""Bidirectionalregulation".

  As described above, in the swing regulating device shown in FIG. 3, when the frame 1 swings more than a certain amount with respect to the rear axle 9 and enters the “bidirectional regulation” operation mode, the frame 1 is largely shaken. In the moved state, the operation mode is changed to “restriction release” and the frame 1 is allowed to swing, so that the posture of the vehicle can be stabilized. Further, since the throttle valves 38 and 39 are provided between the accumulator 19 and the upper chamber 13a and the lower chamber 13b of the hydraulic cylinder 13, respectively, when the electromagnetic switching valve 36 is switched to the shut-off position 36a, The hydraulic oil in the chamber 13a and the lower chamber 13b is prevented from flowing in and out. The increase in hydraulic pressure can be absorbed by the accumulator 19 when the hydraulic passages 16 and 17 expand, and the hydraulic oil can be replenished from the accumulator 19 when oil leaks. Thus, a simple hydraulic circuit configuration is achieved, the size of the hydraulic cylinder 13 can be reduced, and the manufacturing cost of the hydraulic circuit can be reduced.

It should be noted that the present invention can be implemented with the following modifications, for example, without departing from the spirit of the present invention.
1. Applicable to vehicles that use a rubber mount support mechanism in which a rubber support is interposed in the frame part that supports the support pin of the rear axle.
2. Applies to vehicles that do not have an LED that displays the failure location.
3. Turn on the rocking restriction operation lamp so that the operator can recognize the rocking restriction operation during the rocking restriction operation.
4. Control was used to determine whether or not rocking regulation is necessary by inputting a specific numerical value when the sensor failed, but when the sensor fails, the frame can be swung immediately without judging whether or not rocking regulation is necessary. Control is performed so that the failure is indicated on the lamp.
5. The control used to input a specific numerical value when a sensor failure occurs and judge whether or not rocking regulation is necessary. However, when the sensor fails, the frame can be swung immediately without judging whether or not rocking regulation is necessary. Control is performed to display a failure on the lamp in a possible state.
6. As a lift sensor, use a limit switch, potentiometer, rotary encoder, cylinder built-in stroke sensor, etc.
7. The steering angle sensor is attached to the king pin part of the rear axle. Instead of this sensor, control using the stroke sensor with built-in cylinder of power steering is used.
8. The swing angle sensor is mounted between the rear axle and the frame. Instead of this sensor, control is performed using a cylinder built-in stroke sensor of a hydraulic cylinder used for swing restriction.
9. The steering angular velocity dr and the steering direction d are compared. If the steering angular velocity dr is a value that decreases the steering angle r, 0 is input to the steering angular velocity dr, and if the steering angle r decreases, the steering angular velocity dr Although the control is made to cancel the movement restriction and minimize the swing restriction time, in order to continue the swing restriction even during slalom traveling, the steering angular velocity dr is converted into an absolute value regardless of the steering direction d. Based on the value, it is determined whether or not the swing control is required during traveling. In this case, since the rocking restriction continues even during slalom traveling, the behavior of rocking when the restriction is released and during the restriction is reduced.
10. When the swing angle y is an error, the swing restriction operation mode is determined only by the travel restriction flag f _S without the swing restriction by the cargo handling restriction flag f _n , but the swing angle y is an error. Is a control that immediately stops swing regulation or performs swing regulation by the cargo handling restriction flag f _n .
11. In the first embodiment shown in FIG. 1, instead of connecting the accumulator to the electromagnetic switching valve, a hydraulic circuit in which the accumulator is connected to the upper chamber of the hydraulic cylinder via the throttle valve as in the third embodiment is used. .
12. A map that matches the height and load was selected from multiple maps that were set in advance with the lift and load. However, only one map is registered and used without setting multiple maps.
13. Although swinging is restricted by both the cargo handling restriction flag fn and the traveling flag fs, only one of them is applied.
It will be appreciated that the present invention extends to these modifications.

  When the frame becomes horizontal or reversely inclined, etc., the instability of the vehicle body is corrected by providing limiting means that can regulate the swing of the frame when the posture of the vehicle becomes unstable. It can be applied to possible uses.

1 Frame 9 Rear axle 13 Hydraulic cylinder 13a Upper chamber 13b Lower chamber 16, 17 Oil passage 18 Electromagnetic switching valve 19 Accumulator 20, 21 Pressure sensor 22 Controller 24 Swing angle sensor 31 Hydraulic cylinder 31a Upper chamber 31b Lower chamber 32, 33 Electromagnetic Switching valve 36 Electromagnetic switching valve 38, 39 Throttle valve

Claims (2)

  In an industrial vehicle in which a frame is swingably supported at a substantially central portion of a rear axle, a hydraulic cylinder is interposed between an end of the rear axle and the frame, and an upper chamber and a lower chamber of the hydraulic cylinder are provided. An oil switching valve that switches between connection and disconnection of hydraulic oil, an accumulator that supplies and discharges hydraulic oil, and means for detecting the swing load of the hydraulic cylinder. Control means for switching the electromagnetic switching valve according to the angle and the swing load of the hydraulic cylinder to control the frame swing, and to allow the return to the opposite side when the frame swing is restricted An industrial vehicle swing control device characterized by comprising:   When the frame swings more than a certain amount with respect to the rear axle and is in a swing restricted state, the load direction of the hydraulic cylinder is detected by the pressure difference between the upper chamber and the lower chamber of the hydraulic cylinder, and the horizontal 2. The apparatus according to claim 1, further comprising control means for temporarily canceling the swing restriction state when a load is applied in a direction returning to the state.

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