JP3548401B2 - Rotary snowplow - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rotary snowplow that controls a traveling hydraulic pump by electric swash plate control by selecting one of two systems, a pedal and a lever.
[0002]
[Prior art]
In a rotary snowplow that travels using a traveling hydraulic pump controlled by a mechanical swash plate, the vehicle speed is adjusted by changing the tilt angle of the traveling hydraulic pump swash plate by a link mechanism such as a push-pull wire. . As a result, the amount of hydraulic oil discharged from the hydraulic pump changes, and this is sent to the hydraulic motor to change the vehicle speed.
[0003]
Adjustment of the vehicle speed is mainly performed by a semi-fixed manual lever called a forward / reverse lever in medium and large vehicles. On the other hand, a pedal-type is adopted in a small-sized vehicle that is occupied by one person. This is because the room is small and the operator needs to perform steering (handle), adjusting the vehicle speed, throwing snow by chute operation, raising and lowering the snow removing device, etc. simultaneously and in parallel, and both hands are blocked. In addition, it is necessary to adjust the vehicle speed with a foot pedal. Note that the upper and lower limits of the engine speed are set in advance by a separately provided semi-fixed lever.
[0004]
[Problems to be solved by the invention]
The vehicle speed adjustment using a pedal is easy to handle because it is close to the feeling of a passenger car, but the speed during the snow removal operation is very low at several km / h. If it is too fast, snow clogging due to overload tends to occur. Performing such delicate speed adjustment by pedal operation with the foot requires a great deal of skill, and since the pedal is returned by the spring force, it must be held by the foot. The fatigue was great.
[0005]
The advantage of the forward / reverse lever is that the friction plate retains its position even after the hand is released, so that the operator does not need to constantly touch it and is less fatigued. Further, delicate speed adjustments are empirically easier with hands, and furthermore, forward / backward movement can be performed with one lever (without switching operation). On the other hand, in the case of a pedal, it is necessary to switch between forward and reverse travel in advance using another switch or the like.
[0006]
In view of the above circumstances, the present inventor has started development of a novel rotary snowplow that combines a pedal and a forward / reverse lever in response to the strong needs of the operator. However, in developing such a type of rotary snowplow, the present inventor has recognized that it is necessary to solve the following technical problems.
[0007]
(1) When developing a rotary snowplow that uses both pedals and forward and backward levers, if this is configured with a conventional mechanical wire link mechanism, the mechanism becomes very complicated and the operating force becomes heavy. Subtle vehicle speed adjustment becomes difficult.
[0008]
(2) When traveling with a normal pedal, the forward / reverse lever is set to the neutral position, but when the travel mode is switched from the pedal to the forward / backward lever, the operator incorrectly moves the forward / backward lever position. If the switching is performed without noticing, there is a danger that the vehicle may suddenly start, or in the worst case, the forward and the reverse may be reversed, contrary to the operator's will (the problem of incorrect starting). This is because, unlike the pedal, the forward / reverse lever mechanically retains its position, so that the operator who is immersed in snow removal work touches the forward / reverse lever by mistake and moves the traveling mode back and forth from the pedal without noticing it. One reason is the careless switching to the lever.
[0009]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a rotary snow plow having a function of controlling the vehicle speed by using a pedal and a forward / reverse lever, and having a function of preventing erroneous starting when the driving mode is switched from the pedal to the forward / backward lever. Is to provide cars.
[0010]
[Means for Solving the Problems]
The inventor has devised the following solution to the problem (1).
・ Employs a traveling hydraulic pump controlled by an electric swash plate and eliminates the mechanical link mechanism such as the conventional push-pull wire.
A sensor (for example, a rotation angle sensor such as a potentiometer) that outputs a vehicle speed signal (for example, voltage) according to the operation amount is installed on the pedal and the forward / reverse lever.
-A switch (running mode selection switch) for switching the vehicle speed signal between the pedal and the forward / reverse lever is installed.
When a signal from each of the sensors is a voltage signal, a traveling amplifier (analog type: voltage / current conversion amplifier) for converting the signal into a prescribed current signal is provided.
As described above, the traveling control adopts the all-electronic traveling control system.
[0011]
The traveling amplifier converts the input voltage from a sensor such as a potentiometer into a prescribed current value and supplies the current value to a proportional valve for controlling a swash plate of a hydraulic pump. Therefore, when the traveling mode is switched from the pedal to the forward / reverse lever, if the operator mistakenly moves the forward / backward lever to a position other than the neutral position, the above-described problem of erroneous starting occurs.
[0012]
The present inventor has devised the following solution to the problem (2).
That is, in the present invention, even if the above-described erroneous operation is performed, danger is avoided by providing a safety device having the following function separately from the traveling amplifier.
[0013]
-If the forward / reverse lever is at a position other than neutral when the driving mode is switched, the speed automatically decelerates and stops.
After that, it is detected that the forward / reverse lever is once returned to neutral by the operator, and thereafter, the operation of the forward / backward lever is made valid.
Based on the matters described above, the present applicant requests a rotary snowplow having the following configuration in each claim as a means for solving the problem.
[0014]
A rotary snowplow according to claim 1, wherein the vehicle speed pedal is urged to be returned to the neutral position at all times, a forward / reverse lever for maintaining the set position, and a vehicle speed corresponding to the operation amount of the vehicle speed pedal. A pedal sensor (POT1) for outputting a signal, a lever sensor (POT2) for outputting a vehicle speed signal according to the operation amount of the forward / backward lever, and a pedal forward / backward selection switch (4) for selecting forward / reverse when the pedal is operated. ), A vehicle speed signal from the pedal sensor and a vehicle speed signal from the lever sensor to select a traveling mode by selecting a traveling mode, and a vehicle speed signal of the pedal selected by the traveling mode selection switch (5). SG1) or a traveling hydraulic pump provided with an electric swash plate control that is tilted by a vehicle speed signal (SG1) of the forward / reverse lever. When the traveling mode is switched from the pedal to the forward-reverse lever side, and when the forward-reverse lever is at a position other than the neutral position, the driving state of the traveling hydraulic pump is stopped. It has a device (2).
[0015]
The rotary snow plow according to claim 2 is the rotary snow plow according to claim 1, wherein the safety device (2) includes a control means (19) and a stop means (13) controlled by the control means. It is characterized by having. The control means (19) determines whether or not the forward / reverse lever has been selected. The traveling mode determination means (S6) determines whether the traveling mode is from the pedal to the forward / reverse lever. Lever neutral position determining means 1 (S8) for determining whether or not the forward / reverse lever is at the neutral position when it is determined to have switched, and outputting a stop control signal when the forward / reverse lever is not at the neutral position. And The stopping means (13) reduces the current to the swash plate controlling proportional valve of the traveling hydraulic pump according to a stop control signal from the lever neutral position determining means 1 (S8) of the control means (19). And stop the vehicle.
[0016]
According to a third aspect of the present invention, in the rotary snow plow according to the second aspect, the control means (19) includes a lever neutral position determination means 2 (S9). The lever neutral position determining means 2 (S9) determines whether or not the forward / reverse lever has returned to the neutral position one or more times after the stop control signal has been output from the lever neutral position determining means 1 (S8). Outputting a stop control signal to the stop means (13) if the return means has never been returned to the neutral position, and a stop control signal to the stop means if the return means has been returned to the neutral position at least once. Stop the output of
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a circuit block diagram of the traveling amplifier 1 and the safety device 2 in the rotary snowplow of the present embodiment.
[0018]
(1) Traveling amplifier 1
POT1 indicates a rotation angle sensor provided on the pedal, and shows a potentiometer as an example. POT2 indicates a rotation angle sensor provided on the forward / reverse lever, for example, a potentiometer.
[0019]
The POTs 1 and 2 are supplied with stabilized bipolar (±) voltages from the traveling amplifier 1 and generate voltages according to the rotation angles of the pedal and the forward / reverse lever.
[0020]
As the tap voltage of the POT 1 provided on the pedal, a voltage in the range of 0 to + is generated. One is connected to the forward side of the pedal forward / reverse selection switch 4, and the other is input to the traveling amplifier 1. This voltage is converted into a voltage whose voltage polarity is inverted by the voltage polarity inverting unit 3, and is connected to the reverse side of the pedal forward / reverse selection switch 4.
[0021]
This voltage is provided for backward movement by the pedal.
Either the forward or backward voltage of the pedal is selected by the pedal forward / reverse selection switch 4.
[0022]
This voltage (pedal) and the voltage of the POT 2 (rotation angle sensor on the forward / reverse lever side) are connected to the traveling mode selection switch 5, and the selected voltage is input to the traveling amplifier 1. This voltage corresponds to the vehicle speed signal SG1.
[0023]
FIG. 2 shows the relationship between the output voltage (vehicle speed signal SG1) of the two rotation angle sensors POT1 and POT2 and the vehicle speed in the forward and backward directions.
[0024]
The vehicle speed signal SG1 is input to the low-pass filter unit 6 of the traveling amplifier 1 and, after cutting off electrical high-frequency noise, is stabilized by the voltage buffer unit 7 to reduce the output impedance.
[0025]
In the time constant circuit 8, an integration circuit is formed by the resistor R1 and the capacitor C1, and a constant gradient is given to a change in the voltage of the vehicle speed signal SG1 when the voltage increases and decreases, so that the change in the vehicle speed does not become steep. Like that.
[0026]
The voltage / current converter 9 generates a bipolar current proportional to the voltage of the vehicle speed signal SG1, and outputs the current to an electric proportional valve solenoid 10 built in for driving the swash plate of the traveling hydraulic pump.
[0027]
The solenoid current detection resistor 11 detects a feedback current from the electric proportional valve solenoid 10 as a voltage.
[0028]
This voltage is fed back to the voltage / current converter 9, and the circuit compensates the solenoid current to a constant value with respect to a current change due to a change in the internal resistance of the electric proportional valve solenoid 10.
[0029]
The brake switch 12 is turned on when the brake is depressed, and drives a stop relay 13 as stop means in the traveling amplifier 1, and the contact of the relay 13 short-circuits the input of the time constant circuit 8 to the ground. As a result, the electric charge of the capacitor C1 of the time constant circuit 8 is discharged via the resistor R1, so that the input voltage of the voltage / current converter 9 decreases with a slope and finally reaches 0V. In response, the current of the electric proportional valve solenoid 10 also decreases to 0 A. That is, by depressing the brake, the vehicle decelerates and stops at a constant speed during traveling. When the vehicle is stopped, the brake is given priority even if the pedal or the forward / reverse lever is operated while the brake is being depressed.
[0030]
The stabilized power supply unit 14 generates and supplies positive and negative stabilized predetermined voltages to the potentiometers (rotation angle sensors POT1 and POT2) and each internal circuit.
[0031]
(2) Safety device 2
The safety device 2 includes, for example, a CPU (arithmetic unit) 20, an A / D converter 21, an input unit 22, a read-only memory (ROM) 23 for storing a control program, and rewriting for control and data storage. It is constituted by a one-chip microcomputer 19 as a control means having a possible memory (RAM) 24, an output section 25 having an open collector output, and an oscillation section 26 in one.
[0032]
The voltage of the selected vehicle speed signal SG1 of the pedal or the forward / reverse lever after the low-pass filter 6 of the traveling amplifier 1 is input to the A / D converter 21 and A / D converted internally.
[0033]
The output unit 25 is configured by an open collector output transistor whose output is turned on / off by a calculation unit in the CPU as shown in FIG. 3, and is wired OR-coupled to the stop relay 13 in the traveling amplifier 1.
[0034]
Since the output unit 25 is an open collector, when the output is OFF, the output unit 25 is disconnected without being electrically involved in the brake signal. (Does not affect the brake signal)
[0035]
The power-on reset circuit 27 generates a reset signal for resetting the one-chip microcomputer 19 when power is turned on.
[0036]
The operation of the safety device 2 focusing on the operation of the one-chip microcomputer 19 will be described. FIG. 4 shows a control flowchart.
[Step 1] (S1)
After the power is turned on, the control program is started by the power ON reset signal.
[0037]
[Step 2] (S2)
The RAM 24 is initialized.
[0038]
[Step 3] (S3)
A forward / reverse lever neutral detection flag (F) for storing that the forward / reverse lever has become neutral is initialized. (0: Neutral not detected 1: Neutral detected)
The data (F) is stored in the RAM 24.
[0039]
[Step 4] (S4)
By turning off the output, the line of the brake signal BK of the stop relay 13 on the traveling amplifier 1 side is electrically disconnected. (Will be irrelevant)
[0040]
[Step 5] (S5)
Read the selection signal of the forward / reverse lever.
[0041]
[Step 6] (S6)
Check that the forward / reverse lever is selected.
If not selected, it returns to the initial state.
If it has been selected, the process proceeds to step 7.
[0042]
[Step 7] (S7)
The voltage of the vehicle speed signal SG1 of the forward / reverse lever is A / D converted by the A / D converter 21 and read.
[0043]
[Step 8] (S8)
From that value, check if the forward / reverse lever is neutral.
If it is neutral (0 V), the routine proceeds to step 11, sets the flag F (1: neutral detection), and proceeds to step 4. (The flag F is stored in the RAM 24.)
If it is not neutral, go to step 9.
[0044]
[Step 9] (S9)
By checking the flag F, it is checked whether neutral has been detected at least once since the forward / reverse lever was selected.
F is 0: never neutral after selecting the forward / reverse lever (→ go to step 10)
F was 1: neutral after selecting the forward / reverse lever (→ go to step 4)
[0045]
[Step 10] (S10)
When the output is turned on, the line of the brake signal BK of the stop relay 13 of the travel amplifier 1 is forcibly grounded to operate, and the vehicle is stopped.
Proceed to step 5 and repeat until the forward / reverse lever is neutral.
[0046]
In the present embodiment, the description is made on the premise of a small-sized rotary snowplow (single-passenger), but the present invention is not limited to this, and can be applied to all types and sizes of rotary snowplows.
[0047]
It is possible in the future that medium and large rotary snowplows may need to use both pedals and forward / reverse levers. For example, there is a possibility that there is a shortage of workers due to the aging of the operators, and that currently two passengers are replaced by one passenger. In this case, the working environment is the same as that of a small rotary snowplow even with a large rotary snowplow.
[0048]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the rotary snowplow of the present invention, there is provided a means for adjusting the vehicle speed of two systems of a forward / reverse lever and a pedal, and a safety for preventing erroneous starting when switching from the pedal to the forward / backward lever during traveling is prevented. Since the device is provided, the means for adjusting the vehicle speed can be freely switched to any system as required, and when the vehicle is switched from the pedal to the forward / reverse lever during traveling, the operator incorrectly positions the forward / backward lever. Even when moving, safety is ensured because no problem of false start occurs.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a main part according to an embodiment of the present invention.
FIG. 2 is a diagram showing a relationship between output voltages (vehicle speed signal SG1) of rotation angle sensors POT1 and POT2 and vehicle speeds in forward and backward directions.
FIG. 3 is a diagram illustrating an example of a specific configuration of an output unit in a one-chip microcomputer that is a control unit according to the embodiment of the present invention;
FIG. 4 is a flowchart illustrating an example of a control procedure according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF REFERENCE NUMERALS 1 traveling amplifier 2 safety device 4 pedal forward / backward selection switch 5 traveling mode selection switch 10 electric proportional valve solenoid 13 stop relay 19 as stop means one-chip microcomputer 20 as control means CPU
POT1 Rotation angle sensor as pedal sensor POT2 Rotation angle sensor as lever sensor

Claims (3)

A vehicle speed pedal that is biased to always return to the neutral position;
A forward / reverse lever that holds the set position,
A pedal sensor that outputs a vehicle speed signal according to the operation amount of the vehicle speed pedal;
A lever sensor that outputs a vehicle speed signal according to the operation amount of the forward / reverse lever,
A pedal forward / backward selection switch for selecting forward / reverse when operating the pedal;
A driving mode selection switch that selects a driving mode by switching a vehicle speed signal from the pedal sensor and a vehicle speed signal from the lever sensor,
A traveling hydraulic pump including an electric swash plate control tilted by a vehicle speed signal of the pedal or the vehicle speed signal of the forward / reverse lever selected by the traveling mode selection switch,
A safety device configured to stop the driving state of the traveling hydraulic pump when the traveling mode is switched from the pedal to the forward / reverse lever side, and when the forward / backward lever is at a position other than the neutral position. When,
Rotary snowplow with a. The safety device,
Traveling mode determining means for determining whether or not the forward / reverse lever is selected; and when the traveling mode determining means determines that the traveling mode has been switched from the pedal to the forward / reverse lever, the forward / reverse lever is neutral. Control means having lever neutral position determining means 1 for determining whether or not the lever is in a position and outputting a stop control signal when the forward / reverse lever is not in the neutral position;
Stopping means for stopping the traveling hydraulic pump by a stop control signal from the lever neutral position determining means 1 of the control means;
The rotary snowplow according to claim 1, comprising: After the stop control signal is output from the lever neutral position determining means 1, it is determined whether the forward / reverse lever has been returned to the neutral position one or more times by the operator. If the lever has not been returned to the neutral position at least once, Outputs a stop control signal to the stop means, and, when returning to the neutral position one or more times, stops the output of the stop control signal to the stop means. 3. The rotary snowplow according to claim 2, wherein

Images