JP2008271675A - Small carrier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small carrier 1 which can run a motor 34 stably at a low speed even in such a state that it is loaded with a cargo, without using an encoder in the self-propelled wheel device 32 of the small carrier 1 which is driven by a DC magnet motor 34. <P>SOLUTION: The small carrier 1 is provided with a current detector 39 which detects a current flowing in the motor 34, a storage means 46 which memorizes a map representing the relation among the revolution, torque and current of the motor 34, a speed setting means, and a governor control means 43 which controls the current so that it may keep the revolution of the motor 34 by computing it from the above map so that it may be the speed set by the above speed setting means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a small transporter having a self-propelled wheel device driven by an electric motor. More specifically, the present invention relates to a technique for controlling a small transporter having a self-propelled wheel device.

Conventionally, the technique of the self-propelled wheel apparatus of the small transporter using an electric motor is publicly known. For example, it is like the technique described in Patent Document 1.
JP 2003-221195 A

  The motor used in the conventional self-propelled wheel device of the small transporter including the configuration disclosed in Patent Document 1 described above is provided with a rotation speed detection means so as to control the speed to a set speed. . That is, when the speed is set by the speed setting means provided on the handle, the inverter performs frequency conversion to change the rotation speed of the electric (AC) motor, but it is set to be in an unloaded state. It is possible to travel at speed. However, it is difficult for an AC motor to travel at a predetermined low speed with a load placed.

  The present invention provides a small transporter that can stably run a motor at a low speed even when a load is placed without using an encoder.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  In other words, according to the first aspect of the present invention, the motor is driven by the motor including a motor, a battery for supplying a direct current to the motor, and means for controlling the current to change the rotation speed of the motor so as to control the speed. A small-sized transporter, wherein current value detection means for detecting a current value flowing through the motor, storage means for storing a map of the relationship between the rotation speed, torque and current of the motor, speed setting means, Control means for controlling the current of the motor so as to maintain the number of rotations of the motor calculated from the map so as to be the speed set by the speed setting means.

  According to a second aspect of the present invention, in the small transporter according to the first aspect, when the travel stop operation is performed, the control means performs a deceleration control of the motor so that the rotation speed of the motor becomes zero, and the electric brake It is provided with the stop means operated as.

  According to a third aspect of the present invention, in the small transporter according to the second aspect, the motor includes an electromagnetic brake, and the control unit operates the electromagnetic brake after a predetermined time elapses after the electric brake is operated. It is provided with a stopping means.

  According to a fourth aspect of the present invention, in the small transporter according to the first aspect, the control means includes a current limiting means for stopping energization when the current value detected by the current value detection means exceeds a set value. It is.

  In claim 5, in the small transporter according to claim 2 or 3, when the main power is turned off, the control means turns off the electric brake and the motor is rotatable. Is.

  According to a sixth aspect of the present invention, in the small transporter according to the first aspect, when a plurality of traveling operation means for operating the rotation direction of the motor are provided, and the control means selects the forward and backward movements simultaneously, The motor is controlled so as not to rotate.

  According to a seventh aspect of the present invention, in the small transporter according to the first aspect, the motor is configured by a DC motor, and includes means for charging the battery with power generation energy supplied from the motor at the time of slope or blacking. Is.

  As effects of the present invention, the following effects can be obtained.

  Since it comprises like Claim 1, the encoder which detects the rotation speed of a motor becomes unnecessary, and cost reduction can be achieved. In addition, it is possible to run at a constant speed even if the load increases, and in particular, it was difficult to run at a very low speed with a conventional AC motor under a load. It becomes.

  Since the self-propelled wheel device is decelerated using the motor as an electric brake, it is not necessary to provide a separate brake device, and the number of parts can be reduced.

  Since the electric brake is activated and the electromagnetic brake is activated after a lapse of a predetermined time, it can be smoothly stopped.

  Since the current limiting circuit limits the value of the current flowing through the motor to a predetermined value or less, the overcurrent can be prevented and the small transporter can be operated more safely.

  Since the power supply is turned off, it can be freely moved manually without being braked, and can be easily moved manually even when the battery is discharged.

  According to the sixth aspect of the present invention, when the forward and backward operations are simultaneously performed, the motor is not rotated, so that an erroneous operation can be prevented and the small transporter can be operated safely.

  According to the seventh aspect of the present invention, since the power generation energy of the motor is charged into the battery, the travel distance in one charge is increased, so that the small transporter can be operated efficiently.

Below, the control apparatus of the small transporter which has the self-propelled wheel apparatus based on this invention is demonstrated with reference to drawings.
1 is a side view of a small transporter having a self-propelled wheel device, FIG. 2 is a front view of the small transporter having a self-propelled wheel device, FIG. 3 is a side view of the self-propelled wheel device, and FIG. 4 is a self-propelled wheel device. FIG. 5 is a schematic configuration diagram of a control means showing an embodiment of the present invention, FIG. 6 is a diagram showing an example of a map, and FIG. 7 is a schematic configuration diagram of a motor drive circuit.
In the following, the front and rear direction is determined with the right direction in FIG. 1 as the front and the left direction as the rear. Moreover, the direction orthogonal to the front-rear direction and the horizontal direction is defined as the left-right direction.

  First, the small transporter 1 will be described with reference to FIGS. 1 and 2. As shown in FIGS. 1 and 2, the small transporter 1 is configured as a small forklift. In the figure, reference numeral 2 denotes a movable base on which the front wheels 3 and 3 and the rear wheels 4 and 5 are installed. Reference numerals 6 and 6 denote masts which are erected substantially in parallel on both sides of the rear part of the base 2. Is a caster support portion provided on each of the left and right rear ends of the base, 8 is a load receiving fork supported by the masts 6 and 6 so as to be able to be raised and lowered, and 9 is erected on the base 2 between the masts 6 and 6 Lifting cylinders 10, 10 are load chains that are stretched between the load receiving fork 8 and the lifting cylinder 9 via a sprocket 12 that is supported by the piston rod 11 of the lifting cylinder 9, and 13 is the lifting cylinder 9 at the upper part thereof. This is a hydraulic drive box in which an elevating lever 14 for operation control is disposed.

  A hydraulic pump that operates the elevating cylinder 9, an electric motor that drives the hydraulic pump, a battery 15, and the like are disposed in the hydraulic drive box 13.

  A rear wheel 5 is disposed on the left and right sides of the rear portion of the base 2, and a self-propelled wheel device 32 described later is disposed on the left and right other sides. The rear wheel 5 is rotatably supported on a support bracket 17 by an axle 16. A pivot shaft 18 erected at the center of the horizontal portion of the support bracket 17 is fitted to the caster support portion 7 and is supported around the axis of the pivot shaft 18 so that the direction can be changed.

  Next, the operation handle 19 will be described with reference to FIGS. 3 and 4. The operation handle 19 includes an operation unit 20, substantially U-shaped handles 21, 21, a control box 22, a handle shaft 23, a support plate 24, a control means 25, a horn 26, and the like. . The handles 21 and 21 are fixed to the left and right sides of the operation unit 20, respectively. On the left side and right side of the operation unit 20, a pair of left and right traveling operation means 27 serving as speed setting means for switching forward and backward (rotation direction of the motor 34) and setting the traveling speed (the number of rotations of the motor 34) are provided. The power button 28 is disposed at the front right side position to enable ON / OFF operation of the main power source, and the upper limit of the traveling speed set by the speed setting means 27 is switched to two levels at the front side left side position. A high / low switching button 41 is provided. By operating the height switching button 41, a height switching switch 48 described later is turned ON / OFF, and the upper limit speed of the small transporter 1 is set. However, this arrangement position is not limited. The upper side of the control box 22 is attached to the lower side of the operation unit 20 via the operation unit support shaft 29. The control box 22 is provided with a control device 25, a horn 26, and the like. The upper end portion of the handle shaft 23 is fixed to the lower side portion of the control box 22, and the lower end portion thereof is fixed to the support plate 24. A horn button 30 and a collision sensor 31 are installed on the upper side of the operation unit 20. By the operation of the horn button 30, a horn switch 47 described later is turned on, and the horn 26 sounds.

  Next, the self-propelled wheel device 32 will be described based on FIGS. 1 to 4. The self-propelled wheel device 32 includes a support bracket 33, a rear wheel 4, a motor 34 including a DC magnet motor, a turning shaft 35, and the like. A lower portion of the support plate 24 is connected to a position below the front portion of the support bracket 33 so as to be rotatable by a horizontal shaft 36. The pivot shaft 35 is erected vertically at the center of the horizontal portion of the support bracket 33. By fitting the swivel shaft 35 to the caster support portion 7 so as to be rotatable, the caster support portion 7 is supported around the axis of the swivel shaft 35 so that the direction of the swivel shaft 35 can be changed, and can be detachably attached. The rear wheel 4 is rotatably supported by an axle 37 below the support bracket 33. The motor 34 is attached to one end side of the axle 37, and a speed reducer 38 is attached to the other end side. The rear wheel 4 is rotationally driven by the motor 34 via a speed reducer 38. However, the electromagnetic brake 42 may be configured to be retrofitted to the motor 34.

  Next, a control configuration of a small transporter having a self-propelled wheel device according to an embodiment of the present invention will be described with reference to FIG.

The control means 25 includes a travel operation means 27, a current detection device 39 for detecting a current value flowing through the motor 34, a brake operating means 40 for operating the motor 34 and the electromagnetic brake 42, a horn switch 47, a height switching switch 48, and a key switch. 51 and the battery 15. The traveling operation means 27 includes a forward switch 50, a reverse switch 49, a variable resistor 54, a reverse switch 53, and the like. The current detection device 39 can also be obtained by detecting and calculating the voltage applied to the resistor. By operating the power button 28, the key switch 51 is turned ON / OFF, and the electric brake described later is turned ON / OFF.
The control means 25 includes storage means (RAM or ROM) 46, motor drive means 45, governor control means 43, current limiting means 44, and the like.
The storage means 46 stores a current value flowing through the motor 34, a map representing the correspondence relationship between the motor rotation rate, efficiency, power and torque, a control program and a calculation program, which will be described later. The governor control means 43 causes a current to flow through the motor driving means 45 so that the rotation speed of the motor 34 becomes the rotation speed (target rotation speed) set by the travel operation means 27, and also controls the rotation speed. By doing so, it works as an electric brake. The current limiting means 44 limits the value of the current flowing through the motor 34 from exceeding a set value. The motor driving means 45 includes a chopper (or inverter) circuit, controls the current, and also functions as a regenerative circuit when traveling on a slope or during blacking. Blacking refers to a case where the electric motor decelerates, or a case where the forward switch 50 is turned OFF and the reverse switch 49 is turned ON during the forward movement to reverse the rotation direction of the motor 34.

  The operation of the self-propelled wheel device 1 using the above configuration will be described below.

When one or both forward positions of the travel operation means 27 and 27 are pushed, the forward switch 50 is turned on, and the rotational speed of the motor 34 can be changed according to the rotation angle of the travel operation means 27. That is, the variable resistor 54 is connected to the rotating shaft of the traveling operation means 27. The rotation position of the travel operation means 27 becomes a set speed, and the motor 34 smoothly rotates from the rotation speed 0 to reach the set rotation speed. Then, the current detection device 39 detects the current value flowing through the motor 34. Then, the governor control means 43 calculates the rotation speed from the map stored in the storage means 46 based on the current value. When the speed set by the travel operation means 27 in the governor control means 43 is different from the speed obtained from the current detection device 39, the motor drive means is set so as to be the speed set by the travel operation means 27. Control the current to 45. Thus, feedback control is performed so as to maintain the rotational speed. Therefore, even when the torque is changed by placing a load on the load receiving fork 8, the current corresponding to the torque is calculated from the map and feedback controlled so as to be maintained at the set rotational speed.
The reverse switch 49 is also turned on when one or both rear positions of the travel operation means 27 and 27 are pressed, and the same operation is performed thereafter.

  Further, when the hand is released from the travel operation means 27, the forward switch 50 is automatically returned to the OFF position by an urging means (not shown), the forward switch 50 is turned OFF, and the motor 34 is decelerated and stopped. The motor 34 is controlled to act as an electric brake and stopped.

  Further, when the electromagnetic brake 42 is attached to the motor 34, the electric brake is activated, and the brake actuating means 40 is activated and the electromagnetic brake 42 is applied after a predetermined time has elapsed. The same applies when the reverse switch 49 is turned off.

  The current limiting means 44 controls the value of the current flowing through the motor 34 to a set value or less.

When the self-propelled wheel device 32 is stopped, the key switch 51 is turned off and the electric brake is turned off when the power button 28 is turned off. That is, since the motor 34 is freely rotatable, the self-propelled wheel device 32 is freed from braking and is allowed to run.
When the power button 28 is turned on, the key switch 51 is turned on and the electric brake is turned on. When the travel operation means 27 is operated to turn on the forward switch 50 or the reverse switch 49, the braking of the electric brake is released and the motor 34 rotates.

  Further, when the self-propelled wheel device 32 is stopped, when the forward switch 50 and the reverse switch 49 are simultaneously turned on by pressing one forward position of the traveling operation means 27, 27 and pressing the other rear position, the electric brake is activated. In operation, the motor 34 does not rotate and the self-propelled wheel device 32 remains stopped.

  As described above, the battery 15 that supplies DC power to the motor 34, the small-sized transporter 1 that travels by the operation of the motor 34, the current value detection device 39 that detects the current value flowing through the motor 34, and the motor 34. The speed of the motor 34 is calculated from the map so that the speed is set by the storage means 46, the speed setting means, and the speed setting means. By providing the control means 25 including the governor control means 43 for controlling the current so as to maintain the current, the motor 34 can be accurately controlled to the set rotational speed. That is, since the map can be used to control the current flowing through the motor 34 and the rotation speed of the motor 34 can be controlled to be constant, there is no need to use an encoder. And even if load changes, such as putting a load on the small transporter 1 at an ultra-low speed, the rotation speed of the motor 34 can maintain a constant speed.

  Further, by operating the motor 34 as an electric brake as a stopping means during braking of the self-propelled wheel device 32, it is not necessary to provide a separate brake device, so that the number of parts can be reduced.

  Further, when the electromagnetic brake 42 is attached to the motor 34, a signal is sent to the brake operating means 40 after a predetermined time elapses after the electric brake is operated, and the electromagnetic brake 42 is operated, whereby the small transporter 1 can be stopped smoothly and can be operated smoothly.

  Further, by providing the control means 25 with current limiting means 44 for preventing the current value detected by the current detection device 39 from exceeding the set value, the value of the current flowing through the motor 34 is set below the set value. Therefore, the small transporter 1 can be safely operated without burning the motor or causing an overcurrent to flow through the motor driving means 45 or the like.

  When the power button 28 is turned off, the electric brake is turned off, so that the small transporter 1 can be easily moved manually even when the battery is discharged.

  Also, a plurality of travel operation means 27, 27 for operating the rotation direction of the motor 34 are provided, and when the forward switch 50 and the reverse switch 49 are simultaneously turned on by the travel operation means 27, 27, the electric brake is activated. Thus, the motor 34 is not rotated, so that erroneous operation can be prevented and the self-propelled wheel device 32 can be operated safely.

  Further, when the vehicle travels on a slope or the like, the motor 34 acts as a generator, and the energy generated when the motor 34 acts as a generator is charged in the battery.

FIG. 7 shows a motor drive circuit, semiconductor elements 71, 72, 73, 74 such as electronic governors and transistors that can be turned on and off, and diodes 75, 76, 77, which allow current to flow in one direction. 78 is bridge-connected. In such a configuration, when the motor 34 is operated to run, the drive control circuit turns on the semiconductor elements 71 and 74 and the semiconductor elements 72 and 73 alternately while controlling the current for a predetermined time. , And control to achieve the set number of rotations. At this time, a current flows like a dotted line or an alternate long and short dash line.
On the other hand, during traveling such as going down a hill, the torque is reduced and the semiconductor elements 71, 72, 73, 74 are turned off, so that the motor 34 in FIG. A current flows like a two-dot chain line, and the battery 15 can be charged.

  Thus, by charging the battery 15 with the power generation energy of the motor 34, the travel distance in one charge is extended, and the small transporter 1 can be operated efficiently.

The side view of the small conveying machine which has a self-propelled wheel apparatus. The front view of the small conveying machine which has a self-propelled wheel apparatus. The side view of a self-propelled wheel device. The top view of a self-propelled wheel device. The schematic block diagram of the control means which shows one Example of this invention. The figure which showed an example of the map. The schematic block diagram of a motor drive circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 15 Battery 19 Operation handle 25 Control means 32 Self-propelled wheel apparatus 34 DC magnet motor 39 Current detection apparatus 40 Brake operation means 42 Electromagnetic brake 43 Governor control means 44 Current limiting means 45 Motor drive means 46 Memory | storage means 51 Key switch 53 Reverse switch 54 Variable resistance

Claims (7)

A small transporter driven by the motor, comprising: a motor; a battery for supplying a direct current to the motor; and a means for controlling the current and changing a rotation speed of the motor to enable speed control, Current value detection means for detecting a current value flowing through the motor, storage means for storing a map of the relationship between the rotation speed, torque and current of the motor, speed setting means, and speed set by the speed setting means And a control device for controlling the current of the motor so as to maintain the rotational speed of the motor calculated from the map. 2. The small transporter according to claim 1, wherein when the travel stop operation is performed, the control unit includes a stop unit that controls the motor to decelerate and operate as an electric brake so that the number of rotations of the motor becomes zero. 3. The small transporter according to claim 2, wherein the motor includes an electromagnetic brake, and the control unit includes a stopping unit that operates the electromagnetic brake after a predetermined time elapses after the electric brake is operated. 2. The small transporter according to claim 1, wherein the control unit includes a current limiting unit that stops energization when a current value detected by the current value detection unit exceeds a set value. The small transporter according to any one of claims 2 and 3, wherein when the main power is turned off, the control means turns off the electric brake and the motor is rotatable. 2. The small-sized vehicle according to claim 1, wherein a plurality of travel operation means for operating the rotation direction of the motor are provided, and the control means controls the motor not to rotate when the travel operation means selects forward and reverse at the same time. Transporter. 2. The small transporter according to claim 1, wherein the motor is a direct current motor, and includes means for charging the battery with power generation energy supplied from the motor during a slope or blacking.