JP2003189402A - Motor-driven working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve handlability of a motor-driven working vehicle by allowing a parked motor-driven working vehicle to be freely pushed/pulled by human power. <P>SOLUTION: The motor-driven working vehicle comprises a control part which releases an electromagnetic brake in ST07 and switches a motor circuit to a condition in which no drive current or short-circuit current flows in a motor in ST08 when three conditions are met: a main switch is on in ST01, a directional speed lever is at neutral position in ST02, and a travel ready lever is at a travel-enabling position in ST03. A parked motor-driven working vehicle can be freely pushed/pulled by human power. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a control technique for stopping an electric work vehicle. 2. Description of the Related Art For example, Japanese Patent Application Laid-Open No.
No. 98407, “Automatic Control Device for Electric Vehicle”
"Conventional technology" is known. According to the prior art described above, according to FIGS. 1 and 3 of the publication, a traveling operation lever 8 capable of designating forward, neutral, and reverse (the reference numerals are those described in the publication. The same applies hereinafter). When the vehicle is moved to the neutral position, the driving of the traveling DC motor 2 is stopped, and the braking by the electromagnetic parking brake 13 is performed after a certain time T1 has elapsed.
Is to stop. [0003] Incidentally, in order to further improve the handleability of the electric work vehicle as in the above-mentioned conventional art,
Even when not working, it is convenient and convenient if the electric work vehicle can be freely moved to any place.
To that end, we want to be able to push and pull freely with human power without relying on power. An object of the present invention is to provide a technique capable of further improving the handleability of an electric work vehicle by allowing a manually operated electric work vehicle to be freely pushed and pulled by human power. is there. [0005] In order to achieve the above object, a first aspect of the present invention is to provide a main power switch and a travel enable command when operating to a travel enabled position and a travel stop when operating to a non-travel enabled position. A travel preparation member that issues a command, a forward speed, a neutral, and a directional speed control member that can designate backward travel; an electric motor that causes the vehicle to run forward or reverse based on the operation of the directional speed control member; An electric work vehicle equipped with an electromagnetic brake for applying a stationary brake such as a parking brake during non-traveling, wherein the electric work vehicle has a condition that a main power switch is on, and a direction speed control member is in a neutral position. And
When the three conditions, that is, the condition that the traveling preparation member is in the traveling position, are satisfied, the electromagnetic brake is released, and the driving circuit and the short-circuit current flow through the driving circuit for the electric motor. A control unit is provided for controlling to switch to a state where no power is supplied. When the main power switch is turned on and the directional speed control member is at the neutral position, the electromagnetic brake is released by operating the travel preparation member to the travelable position. At the same time, the drive circuit for the electric motor switches to a so-called free mode in which no drive current or short-circuit current flows in the electric motor. As a result, the stationary braking of the vehicle is released, and the electric motor is in a free-running state where no current flows. The stopped electric powered vehicle can be pushed and pulled freely by human power. Therefore,
The electric work vehicle when not working can be freely and easily moved to an arbitrary place with only human power. The handleability of the electric work vehicle is further improved. Barn, warehouse,
It is extremely easy to carry in and carry out the work to and from the truck bed. An embodiment of the present invention will be described below with reference to the accompanying drawings. Note that "before", "after",
“Left”, “right”, “up”, and “down” follow directions viewed from the operator, where L indicates left and R indicates right. Also, the drawings should be viewed in the direction of reference numerals. FIG. 1 is a plan view of a snow blower according to the present invention. A snow blower 10 as an electric vehicle has an engine 12 mounted on a body 11 and an auger 13 and a blower as a working unit at the front of the body 11. 14, crawlers 15 </ b> L and 15 </ b> R are arranged on the left and right sides of the body 11, and an operation panel 16 is arranged on the rear part of the body 11.
It is a walk-behind work machine that will take you from behind. Hereinafter, the main part will be described in detail. The operation panel 16 will be described in detail with reference to FIG. [0009] A part of the output of the engine 12
To supply the obtained electric power to the battery (see reference numeral 43 in FIG. 4) disposed below the operation panel 16 and to the left and right traveling motors described later. The remainder of the output of the engine 12 is used for rotation of the blower 14 and the auger 13 as a working unit via the electromagnetic clutch 18 and the belt 19. The auger 13 has a function of collecting the snow accumulated on the ground at the center, and the blower 14 receiving the snow projects the snow via the shooter 21 to a desired position around the body 11. 22
Denotes an auger housing, which is a cover member surrounding the auger 13. The left crawler 15L is wound around a driving wheel 23L and an idle wheel 24L. In the present invention, the driving wheel 23L is rotated forward and reverse by a left traveling motor 25L. The right crawler 15R is also wound around the driving wheel 23R and the idle wheel 24R. In the present invention, the driving wheel 23R is rotated forward and reverse by the right traveling motor 25R. In the conventional snow blower, one engine (gasoline engine or diesel engine) is used to cover the working part system (auger rotating system) and the traveling system (crawler driving system). The drive system (auger rotation system) is driven by an electric motor (travel motors 25L, 25L).
R) drives a traveling system (crawler drive system). Based on the belief that an electric motor is appropriate for fine running speed control, turning control, and forward / reverse switching control, a working unit system that receives a sudden load change is suitable for a powered internal combustion engine. I did that. FIG. 2 is a view taken in the direction of arrow 2 in FIG.
Has a main switch 28 on the side in front of the operation box 27,
An engine choke 29, a clutch operation button 31 and the like are provided.
The operation box 2 includes an auger housing attitude adjusting lever 33, a directional speed lever 34 as a directional speed control member related to the traveling system, and an engine throttle lever 35 related to the working unit system.
7 is provided with a grip 36R and a right turning operation lever 37R on the right side, and a left side of the operation box 27 is provided with a grip 36L, a left turning operation lever 37L and a traveling preparation lever 38. Although the left and right turning operation levers 37L and 37R are similar to brake levers, a complete braking effect cannot be obtained as described later. By operating the travel motor 25L,
Since it is used to turn the body by reducing the rotation of 25R, it was decided to call it a turning operation lever instead of a brake lever. The main switch 28 is a well-known main power switch capable of starting the engine by inserting and turning a main key. By pulling the engine choke 29, the concentration of the air-fuel mixture can be increased. The snow throwing direction adjusting lever 32 is a lever operated when changing the direction of the shooter (21 in FIG. 1). The auger housing attitude adjusting lever 33 is an auger housing (2 in FIG. 1).
This lever is operated when changing the posture of 2). The operation of the other members will be described with reference to FIG. FIG. 3 is a view taken in the direction of the arrow 3 in FIG. 2, and the potentiometer 39
The angle of the L arm 39a can be rotated to the position of the imaginary line. The potentiometer 39L is a device that emits electric information according to the rotational position of the arm 39a. The travel preparation lever 38 is a travel preparation member acting on the switch means 42. When the spring 41 pulls the state (free state) as shown in FIG. Become. When the travel preparation lever 38 is lowered clockwise in the drawing to the travelable position with the left hand of the operator, the switch means 42 is turned off. In this way, the switch means 42 can detect whether the travel preparation lever 38 is gripped. Thus, the travel preparation lever 38 as a travel preparation member is
The switch 42 issues a travel enable command when operated to the runnable position, and issues a travel stop command from the switch 42 when operated to the non-runnable position. FIG. 4 is a control system diagram of the snow blower according to the present invention, which shows devices and information transmission paths in the control unit 44 built in or attached to the operation panel. Generally, squares indicate devices and circles indicate drivers. . And the engine 1 surrounded by the imaginary line frame
2. The electromagnetic clutch 18, the blower 14, and the auger 13 are a working unit system 45, and the other is a traveling system. 43 is a battery. Although the flow of the command is indicated by a broken line in the control unit 44 for the sake of convenience, this is merely a reference description. First, the operation of the working unit system will be described. By inserting a key into the main switch 28 and turning it to a start position, the engine 12 is started by rotation of a cell motor (not shown). The engine throttle lever 35 is connected to a throttle valve 4 with a throttle wire (not shown).
8, the engine throttle lever 35
, The opening of the throttle valve 48 can be controlled. Thereby, the rotation speed of the engine 12 can be controlled. By operating the clutch operation button 31 while holding the travel preparation lever 38, the electromagnetic clutch 18 is connected at the will of the operator, and the blower 14 and the auger 1 are connected.
3 can be turned. The electromagnetic clutch 18 can be disengaged by either releasing the travel preparation lever 38 or operating the clutch operation button 31. Next, the operation of the traveling system will be described. The snow blower of the present invention includes left and right electromagnetic brakes 51L and 51R as brakes equivalent to a parking brake of a normal vehicle, and these electromagnetic brakes 51L and 51R are controlled by the control unit 44 during parking. In state.
Therefore, the electromagnetic brakes 51L and 51R are released in the following procedure. Under the condition that the main switch 28 is in the start position (on), the traveling preparation lever 3
When the user grips 8, the electromagnetic brakes 51L and 51R enter the released (non-brake) state. FIG. 5 is an explanatory view of the operation of the directional speed lever employed in the present invention. The directional speed lever 34 can be reciprocated by the operator's hand as indicated by an arrow, and moves forward from the "neutral range". Side, the vehicle can move forward, and in the “forward” area, Lf moves forward at a low speed, H
Speed control can also be performed so that f advances at high speed. Similarly, if the vehicle is tilted toward the "reverse" side from the "neutral range", the vehicle can be moved backward. In the "reverse" region, speed control can also be performed such that Lr is at a low speed reverse and Hr is at a high speed reverse. In this example, as shown at the left end of the figure, the position of the potentiometer was adjusted so that the maximum reverse speed was 0 V (volt), the maximum forward speed was 5 V, and the neutral range was 2.3 V to 2.7 V. Generate voltage. With one lever, you can set the forward / backward direction and high / low speed control,
The directional speed lever 34 was named. Returning to FIG. 4, the control unit 44, which has obtained the position information of the directional speed lever 34 from the potentiometer 49, turns the left and right traveling motors 25L, 25R via the left and right motor drivers 52L, 52R, and the traveling motor 25L. , 2
The rotation speed of 5R is detected by the rotation sensors 53L and 53R, and feedback control is performed based on the signals so that the rotation speed becomes a predetermined value. As a result, the left and right driving wheels 23L, 23R rotate in a desired direction at a predetermined speed,
It becomes a running state. The braking during running is performed in the following procedure. In the present invention, the motor drivers 52L and 52R include regenerative braking circuits 54L and 54R. In general terms, the electric motor rotates by supplying electric energy from the battery to the electric motor. A generator, on the other hand, is a means of converting rotation into electrical energy. Therefore, in the present invention, the traveling motors 25L and 25R are changed to generators by electric switching to generate power. If the generated voltage is higher than the battery voltage, the electric energy can be stored in the battery 43. This is the operating principle of the regenerative brake. The degree of grip of the left turning operation lever 37L is detected by a potentiometer 39L, and in response to this detection signal, the control unit 44 activates the left regenerative brake circuit 54L to reduce the speed of the left traveling motor 25L. The degree of grip of the right turning operation lever 37R is detected by the potentiometer 39R, and the control unit 44 activates the right regenerative brake circuit 54R in response to the detection signal, and the right traveling motor 25R
Decrease speed. That is, the user can make a left turn by gripping the left turn operation lever 37L, and can make a right turn by gripping the right turn operation lever 37R. The traveling can be stopped by any of the following. Return the main switch 28 to the off position.
The directional speed lever 34 is returned to the neutral position. Release the travel preparation lever 38. The short-circuit brake circuit 55L is a circuit that literally short-circuits both poles of the traveling motor 25L, and this short-circuit causes the traveling motor to be in a sudden braking state. Since the same applies to the short-circuit brake circuit 55R, the description is omitted. FIGS. 6A and 6B are a drive circuit diagram and a mode table for the electric motor employed in the present invention.
(A), an electric motor 25L as a traveling motor
The high frame (upper half of the circuit) of the driving circuit 56 is connected to the power supply 58, the low frame (lower half of the circuit) is dropped to the ground 59, the E drive element 61 is provided in the left high frame, and the left The F drive element 62 is arranged, the G drive element 63 is arranged on the right high frame, and the H drive element 64 is arranged on the right low frame (E to H are added for convenience). Diodes 65 to 68 are provided as a bypass circuit.
The E to H drive elements 61 to 64 perform on / off control electrically by a driver (not shown). Hereinafter, the electric motor 25L
Is simply referred to as a motor circuit 56. The same applies to the traveling motor 25R, and illustration and description are omitted. The power supply 58 is connected to the battery 43 of FIG.
Is equivalent to The E to H drive elements 61 to 64 are F
A field effect transistor called ET is preferred. FETs are voltage-driven, high impedance elements, whereas ordinary transistors are low-impedance elements that work with current. Since the impedance is high, it can be said that the element is suitable for being interposed in the motor circuit 56 as shown in the figure. (B) is a mode table in the circuit of the traveling motor. The mode name is shown on the left, and the states of the E to H drive elements are shown on the right by ON or OFF. In the short-circuit brake mode in the first row, the F drive element and the H drive element
N, and turn off the E drive element and the G drive element. In (a), the power supply 58 and the traveling motor 25L are disconnected, and a short circuit is formed on the low frame side. As a result, the traveling motor 25L is suddenly braked. This state is called a short-circuit brake. In the forward mode in the second row, the E drive element and the H drive element are turned on, and the F drive element and the G drive element are turned off. In (a), the current is E
Since the drive element 61, the travel motor 25L, and the H drive element 64 flow in this order, the travel motor rotates forward. In the reverse mode in the third row, the rotation is reversed.
In the free mode in the fourth row, all of the E to H drive elements were turned off. Since all the current including the driving current and the short-circuit current does not flow through the traveling motor, the traveling motor can idle freely. In the forward mode and the reverse mode,
The traveling motor can be controlled. For example, in the forward mode, a pulse width modulation signal (PWM signal) for control is issued to the E drive element to perform forward rotation control of the traveling motor. In the reverse mode, the control drive PW is applied to the G drive element.
By issuing the M signal, the reverse rotation control of the traveling motor is performed. Next, a control flow when the control unit 44 shown in FIG. 4 is a microcomputer will be described with reference to FIG.
It will be described based on. In the figure, STxx indicates a step number. Step numbers that are not particularly described proceed in numerical order. FIG. 7 is a control flowchart of the control unit according to the present invention. ST01: Check whether the main switch is on. If YES, proceed to ST02; if NO, ST
Go to 05. ST02: It is checked whether or not the direction speed lever (reference numeral 34 in FIG. 4) is at the neutral position. If YES, the process proceeds to ST03, and if NO, the process proceeds to ST04. ST03: It is checked whether or not the travel preparation lever (reference numeral 38 in FIG. 4) is at a travelable position (a travelable position by gripping). If NO, proceed to ST05, if YES, ST
Proceed to 07. ST04: It is checked whether or not the travel preparation lever is at the travelable position. If YES, the process proceeds to ST09, and if NO, the process proceeds to ST11. ST05: Electromagnetic brake (reference numeral 51 in FIG. 4)
L, 51R) is switched to a braking state, that is, a braking state. ST06: The motor circuit (reference numeral 56 in FIG. 6) is switched to the free mode. ST07: The electromagnetic brake is switched to the non-braking state, that is, the released state. ST08: Switch the motor circuit to the free mode. ST09: The electromagnetic brake is switched to the non-braking state. ST10: The traveling of the electric motor is controlled by switching the motor circuit to the forward mode or the reverse mode. That is, a PWM signal for control is issued to the motor circuit to execute the rotation control of the electric motor. ST11: The electromagnetic brake is switched to the braking state. ST12: Switch the motor circuit to the short-circuit brake mode. The above control flow will be organized and described based on the following table. [Table 1] In this table, the control modes of the first row, the control modes of the second row,... Are described in order from the top, and the control modes of each row will be described. In the control mode in the first row, when the main switch is off, the electromagnetic brake is brought into the braking state and the motor circuit is switched to the free mode. The control mode of this first row is ST0
1, ST05 and ST06. In the control mode of the second row, there are three conditions: a condition that the main switch is on, a condition that the directional speed lever is in the neutral position, and a condition that the traveling preparation lever is in the non-traveling position. When the condition is satisfied, the electromagnetic brake is brought into the braking state and the motor circuit is switched to the free mode. The control modes in the second row are ST01, ST02, ST03, ST05, ST0.
Equivalent to 6. In the control mode of the third row, there are three conditions: a condition that the main switch is ON, a condition that the directional speed lever is in the neutral position, and a condition that the travel preparation lever is in the travelable position. Is satisfied,
The electromagnetic brake is released, that is, brought into a non-braking state, and the motor circuit is switched to the free mode. The motor circuit in the free mode is a state in which the drive current and the short-circuit current do not flow through the electric motor. The control modes in this third row are ST01, ST02, ST03, ST07, ST0
Equivalent to 8. According to the control mode in the third row, the braking operation when the vehicle is stopped is in the released state, and the electric motor is in a free-running state in which no current flows. Stopped electric work vehicle,
It can be pushed and pulled freely by human power. In the control mode in the fourth row, the condition that the main switch is on, the condition that the directional speed lever is in the forward position or the reverse position, and the condition that the travel preparation lever is in the travelable position are as follows. When the three conditions are satisfied, the electromagnetic brake is released and the motor circuit is switched to the forward mode or the reverse mode. This fourth
The row control modes are ST01, ST02, ST04, S
This corresponds to T09 and ST10. According to the control mode in the fourth row, when the direction speed lever is at the forward position, the electric motor is normally rotated to execute forward traveling control. When the directional speed lever is at the reverse position, the electric motor is reversely rotated to execute reverse traveling control. In the control mode of the fifth line, the condition that the main switch is on, the condition that the directional speed lever is in the forward position or the reverse position, and the condition that the travel preparation lever is in the non-travelable position are as follows. When the three conditions are satisfied, the electromagnetic brake is brought into the braking state and the motor circuit is switched to the short-circuit brake mode. The control modes in the fifth row are ST01, ST02, ST0
4, ST11 and ST12. According to the control mode in the fifth row, the electric motor is suddenly braked. In summary, the present invention provides a main power switch (reference numeral 28 in FIG. 4) and a travel preparation command that issues a travel enable command when operated to a travel enabled position and issues a travel stop command when operated to a non-travel enabled position. Member (3 in FIG. 4)
8), a directional speed control member (reference numeral 34 in FIG. 4) capable of designating forward, neutral, and reverse, and a pair of left and right wheels that cause the vehicle to run forward or reverse based on the operation of the directional speed control member Electric motors (reference numerals 25L, 25 in FIG. 4)
R) and a pair of left and right electromagnetic brakes (reference numerals 51L and 51R in FIG. 4) for applying a stationary brake such as a parking brake when the vehicle is not running. In this electric work vehicle, a condition that the main power switch is on (ST01 in FIG. 7) and a condition that the directional speed control member is in the neutral position (ST02 in FIG. 7).
And the condition that the travel preparation member is at the travelable position (ST03 in FIG. 7),
With the electromagnetic brake released (ST07 in FIG. 7),
A control circuit (reference numeral 44 in FIG. 4) controls the drive circuit for the electric motor (reference numeral 56 in FIG. 6) so as to switch to a state in which the drive current and the short-circuit current do not flow in the electric motor (ST08 in FIG. 7). It is characterized by having. Therefore, in FIG. 4, when the main power switch 28 is turned on and the directional speed control member 34 is set to the neutral position, the travel preparation member 38 is operated to the travelable position, whereby the electromagnetic brakes 51L, 51R are operated. Is open. At the same time, the drive circuit (reference numeral 56 in FIG. 6) for the electric motors 25L and 25R switches to a so-called free mode in which the drive current and the short-circuit current do not flow through the electric motors 25L and 25R. As a result, when the vehicle is stopped, the braking is released, and the electric motors 25L and 25R are in a state in which no current flows and are free to spin. The stopped electric powered vehicle can be pushed and pulled freely by human power. The electric work vehicle to which the present invention is applied is not limited to a snow blower, but may be of any type as long as it is an electric vehicle such as an electric carrier, an electric golf cart, or a lawn mower. Although the snow blower of the embodiment has left and right traveling motors, the present invention can be applied to an electric work vehicle in which one traveling motor drives left and right driving wheels. Furthermore, the direction speed lever is one in the embodiment, but the role may be shared by a plurality of levers. The direction / speed control member may be a lever, a dial, a switch or an equivalent. Similarly, the travel preparation member may be a lever, a dial, a switch, or the like. The main power switch is not limited to a switch for starting the engine, and may be any switch that becomes a main switch of a traveling system of the electric work vehicle. According to the present invention, the following effects are exhibited by the above configuration. When the main power switch is turned on and the directional speed control member is set to the neutral position, the travel preparation member is operated to the travelable position to open the electromagnetic brake and to release the electromagnetic brake. Can be switched to a so-called free mode in which the drive current and the short-circuit current do not flow through the electric motor. As a result, the stationary braking of the vehicle is released, and the electric motor is in a free-running state where no current flows. Stopped electric work vehicle,
It can be pushed and pulled freely by human power. Therefore, the electric work vehicle when not working can be freely and easily moved to an arbitrary place with only human power. The handleability of the electric work vehicle is further improved.
For example, it is extremely easy to carry out and carry out work to a barn, a warehouse, a truck bed and the like.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a snow blower according to the present invention. FIG. 2 is a view as viewed in the direction of arrow 2 in FIG. 1 FIG. 3 is a view as viewed in the direction of arrow 3 in FIG. FIG. 5 is an explanatory diagram of the operation of the directional speed lever employed in the present invention. FIG. 6 is a drive circuit diagram and a mode table for an electric motor employed in the present invention. Control Flowchart of Control Unit [Description of References] 10 ... Snow Removal Machine as Electric Work Vehicle, 11 ... Body, 13,
14 ... Auger and blower for snow removal as working part, 23
L, 23R: running wheels; 25L, 25R: running motor as electric motor; 28, main switch as main power switch; 34, directional speed lever as directional speed control member; 38, running preparation lever as running preparation member , 4
4 ... control unit, 51L, 51R ... electromagnetic brake, 56 ... drive circuit (motor circuit) for electric motor.

Continuation of front page    (72) Inventor Tsutomu Inui             1-4-1 Chuo, Wako-shi, Saitama Stock Association             Inside the Honda Research Laboratory F term (reference) 5H115 PA08 PG10 PI16 PU01 PV03                       PV09 PV24 QE12 RB17 SE03                       TR05 TU02 UI34

Claims (1)

Claims: 1. A main power switch, a travel preparation member that issues a travel enable command when operated to a travelable position and issues a travel stop command when operated to a non-travelable position, forward, neutral, and reverse travels. Directional speed control member, an electric motor that causes the vehicle to run forward or reverse based on the operation of the directional speed control member, and an electromagnetic that applies a stationary brake such as a parking brake when the vehicle is not running. An electric work vehicle equipped with a brake, wherein the electric work vehicle has a condition that the main power switch is turned on, a condition that the directional speed control member is at a neutral position, and a condition that the travel preparation member can travel. The electromagnetic brake is released and the drive for the electric motor is released when three conditions are met: Road, and controls so as to switch the state in which the drive current and short-circuit current does not flow to the electric motor, an electric work vehicle which is characterized in that it comprises a control unit.