JPH02289706A - Speed control device for rotary snowplow - Google Patents

Abstract

PURPOSE:To enable the control of the optimal condition at any time and improve the snow removing efficiency by setting the optimal control characteristic for respective combinations of travelling speed stage, and speed stage of a snow removing device and snow removing cross-sectional area, and performing control on the basis of them. CONSTITUTION:The optimal control characteristic for respective conditions corresponding to the combination of speed stage of a travelling transmission 3, speed stage of a transmission 7 for a snow removing device and snow removing cross-sectional area are set on the basis of theory and result of experiment. When the load of the snow removing device 9 is light and the engine speed N is larger than the reference speed N0, the HST swash plate angle theta is maintained at a constant value theta0 so as to prevent the higher speed than required. When the engine speed N is between the reference speed N0 and the engine speed NL unsuitable for snow removing work, the HST swash plate angle theta is reduced in proportion to the lowering amount of the engine speed N. Further, when the engine speed N is fallen below the engine speed NL, the HST swash plate angle theta is made 0.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a speed control device for a low-rise snowplow.

<Prior art> Snow removal work using a snowplow requires complicated operations such as adjusting travel speed, changing direction, and controlling the snow removal device in response to changes in load, surrounding traffic conditions, roadside conditions, etc. Therefore, a high level of skill is required for talented beret players.

In particular, the running speed needs to be adjusted frequently while monitoring snow conditions and changes in engine rotational speed to prevent engine overload and the resulting clogging of the snow chute. If the snow removal is done at a speed that allows the engine output to be used, the operation will be easier, or the snow removal efficiency will be reduced.

Therefore, in order to reduce the burden on the operator of a low-speed snowplow, changes in the engine rotation speed corresponding to changes in the load on the snowplow are detected, and based on this signal, the HST (HydroStatic
A technology has been proposed to automatically control the traveling speed and prevent engine overload by adjusting the swash plate angle of the transmission (Japanese Patent Laid-Open No. 58-146).
No. 608, Japanese Utility Model Application Publication No. 17753/1983, Japanese Patent Application Publication No. 175404/1982, Japanese Patent Application Publication No. 1987/106006
(see publication).

Problems to be Solved by the Invention> However, in the above-mentioned prior art, the speed stage of the traveling transmission,
Since control is performed using fixed control characteristics without considering the speed stage and snow removal cross-sectional area of the snow removal device transmission, the following problems occur.

That is, in the snow removal device of a rotary snowplow, snow shoveled by an auger is taken into a blower and blown away from a chute (snow thrower). The snow throwing distance varies depending on the site conditions (road and surrounding conditions). Set the speed of the snow removal device transmission depending on the distance you want to throw snow.

When you change the speed stage of the snow removal device, the amount of snow removed by the blower (the amount of snow that can be processed by the blower) changes based on the power distribution.
The relationship can be expressed as Qb: amount of snow removed by the blower is: reduction ratio N of the transmission for the snow removal device: engine rotational speed. That is, it is proportional to the square of the reduction ratio of the snow removal transmission and inversely proportional to the engine rotation speed.

Based on equation (1), the relationship between the snow removal cross-sectional area and vehicle speed when the engine speed is constant and the amount of snow removed by the blower is the standard, and the speed gear of the snow removal equipment transmission is used as a parameter.
An example is shown in FIG.

In the area above the curve in Figure 5, the power required for the snow removal device increases, causing an overload on the engine.
Snow removal becomes impossible, the chute becomes clogged, and the shear bottle breaks.

Therefore, the snow removal speed (vehicle speed) has an upper limit determined by the speed gear of the snow removal device transmission and the snow removal cross-sectional area. For example, if the speed stage of the transmission for a snow removal device is set to 1st speed, the snow throwing distance may be small, so the load is small and the upper limit of the vehicle speed can be increased. Further, when the speed of the transmission for the snow removal device is set to third speed, the snow throwing distance becomes longer and the snow removal load increases, so the upper limit of the vehicle speed must also be lowered.

However, in the conventional technology, the upper limit of the vehicle speed is not determined according to the speed stage of the snow removal equipment transmission, so when snow removal is started by automatic driving or due to unevenness of snow, the load on the snow removal equipment becomes smaller, and the load on the snow removal equipment decreases. The vehicle speed will automatically increase. If this happens, the next time the load increases, the upper limit of the vehicle speed corresponding to the load may be exceeded, causing the above-mentioned problems.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a speed control device for a low-rise snowplow that prevents engine overload, prevents clogging of the snow chute, and enables efficient snow removal.

Means for Solving the Problem 〉 As shown in Fig. 1.2, the means for solving the problem according to the present invention includes an engine 1, a distributor 2 that distributes the output of the engine 1 to the traveling device side and the snow removal device side. , an HST 5 driven by one output of the distributor 2, a traveling transmission 3 to which the output of the HST 5 is input, and a snow removal device transmission 7 driven by the other output of the distributor 2. In the rotary snow removal vehicle, a travel lever position detector AI detects the speed gear of the travel transmission 3, and a snow removal lever position detector A2 detects the speed gear of the snow removal device transmission 7 described in 1rj.
Based on the signals from the rotational speed detector A4 that detects the rotational speed N of the engine 1, the travel lever position detector AI, the snow removal lever position detector A2, the rotational speed detection 5A4, and the snow removal cross-sectional area setting device IO. A microcomputer 11 is provided for automatically controlling the swash plate angle θ of the HST 5 under the following conditions (a) to (d).

Condition (a) NL≦N≦No, θ-θ0-K (No-N) Same (b) N>N. So, θ=θ.

Same (c) If N < N L, θ10 Same (d)
θ in almost inverse proportion to an increase in the speed stages of the traveling transmission 3 and the snow removal device transmission 7 and an increase in the set value of the snow removal cross-sectional area setting device IO. decrease.

however, K is a constant, No is the standard rotational speed of the engine, NL is an engine rotation speed inappropriate for snow removal work.

<Operation> In the problem solving means described above, control characteristics are set for each combination of travel speed stage, snow removal device speed stage, and snow removal cross-sectional area, and the basic form thereof is as shown in FIG.

In FIG. 3, the load on the snow removal device is light and the engine rotation speed is the reference rotation speed N. When it is larger than , the HST oblique angle θ is kept constant so as not to increase the speed more than necessary.

N. to the rotation speed NL, which is inappropriate for snow removal work,
Decrease the HST swash plate angle θ in proportion to the decrease in engine speed.

When the engine speed is below NL, the HST swash plate angle θ is kept at zero.

The traveling lever position detector Al detects the setting of the traveling speed gear, and the snow removal lever position detector A2 detects the setting of the speed gear of the blower of the snow removal device, and inputs them to the microcomputer I1.

On the other hand, information on the snow removal cross-sectional area is input from the snow removal cross-sectional area setting device IO.

The microcomputer 11 selects N from pre-stored data based on the information on the travel speed stage, blower speed stage, and snow removal cross-sectional area. SNL, θ. , K to set control characteristics suitable for the working conditions.

Changes in the engine rotational speed due to changes in the load of the snow removal device are detected by the rotational speed detector A4 and input manually to the microcomputer 11. Microcomputer 11
calculates the HST swash plate angle θ corresponding to the engine rotational speed input from the above set control characteristics and performs control.

In this way, the basic form of the control characteristics as shown in Fig. 3 is set, and the No. , NL, Qo and K are determined and set as their respective control characteristics.

Therefore, in any combination, it is possible to always achieve optimal control, which allows efficient snow removal without causing any problems.

Example Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram of the power system of a low-rise snowplow.

The output of the engine I is distributed and transmitted to the traveling device side and the snow removal device side by the distributor 2. There is a traveling transmission 3 on the traveling device side, and the traveling speed can be changed by a lever 4 operated by the driver.

There is an HST 5 between the distributor 2 and the driving transmission 3, and an operating lever 6 that moves a swash plate for changing the discharge amount of the variable capacity bomb controls the forward and backward movement of the front wheels W1 and the rear wheels W2 of the vehicle and the above-mentioned driving speed stage. It is possible to adjust the speed within a range corresponding to the settings.

On the other hand, there is a snow removal device transmission 7 on the snow removal device side, and the speed stage of the snow removal device 9 can be changed by a lever 8 in order to change the snow throwing distance.

FIG. 2 is a block diagram showing the configuration of a speed control device for a rotary snowplow according to the present invention. In the figure, a travel lever position detector A1 detects the setting of the travel speed gear from the position of the travel speed gear changeover lever 4.

The snow removal lever position detector A2 detects the speed stage of the snow removal device (rower and blower) from the position of the snow removal device speed change lever 8.

The snow removal cross-sectional area setting device 10 is a setting device for inputting information on the snow removal cross-sectional area into the microcomputer 1l. It is operated by the operator according to the construction method used during the work.

FIG. 3 is a basic characteristic diagram of the control according to the present invention. In these FIGS. 2 and 3, the low-rise snowplow has an engine 1 and a distribution system that distributes the output of the engine 1 between the traveling device side and the snow removal device side. a snow removal machine 2, an HST 5 driven by the output of one of the distributors 2, a traveling transmission 3 to which the output of the HST 5 is input, and a snow remover driven by the output of the other distributor 2. The device is equipped with a transmission 7 for the device.

The speed control device of the present invention includes the traveling transmission 3.
a travel lever position detector AI for detecting the speed stage of the snow removal device transmission 7, a snow removal lever position detector A2 for detecting the speed stage of the snow removal device transmission 7, and a rotation speed detector for detecting the rotation speed N of the engine l. A4 and these travel lever position detectors A
I, the HS based on the signals from the snow removal lever position detector A2, the rotation speed detector A4, and the snow removal cross-sectional area setting device 10.
A microcomputer 1l is provided to automatically control the swash plate angle θ of T5 under the following conditions (a) to (d).

Condition (a) If NL≦N≦No, θ-θ. -K(NoN
) Same (b) If N > No, θ-0.

Same (c) If N < N L, θ=0 Same (d)
θ in almost inverse proportion to an increase in the speed stages of the traveling transmission 3 and the snow removal device transmission 7 and an increase in the set value of the snow removal cross-sectional area setting device 10. decrease. However, K is a constant, No is the reference rotational speed of the engine 1, and NL is the rotational speed of the engine 1 unsuitable for snow removal work.

For example, the speed stage of the traveling transmission 3 is set to 1st gear (reduction ratio 4.1
69) to second speed (reduction ratio 2.277), θ. from rlJ to IO. It is reduced at a rate of 546J. The speed stage of the snow removal device transmission 7 is set to 1st speed (reduction ratio 2.
263) to second speed (reduction ratio 1.816), θ. is reduced from "l" by the ratio of two, such as [0.643j. Furthermore, when the set value of the snow removal cross-sectional area setter 10 is increased by N times, θ0 is decreased to 17H.

FIG. 4 is a flowchart showing an outline of a program for achieving the above control according to the present invention.

Generally, the load on a snow removal device is a function of the specific gravity of snow, the snow removal cross-sectional area, the snow removal speed (traveling speed), and the blower speed. In order to increase the snow throwing distance, the blower must be rotated at high speed.
In other words, it is necessary to reduce the product of the snow removal cross-sectional area and the snow removal speed. In addition, when changing the driving speed stage, the vehicle speed, or HST, is
There is a limit to the maximum value of the swash plate angle. In this way, the range of the HST swash plate angle that should be controlled in order to prevent engine overload varies depending on the combination of the travel speed stage, the snow removal device speed stage, and the snow removal cross-sectional area.

On the other hand, if the snow removal device is driven into snow at high speed when the power distribution requires snow removal at a low speed, a large load will suddenly be applied to the snow removal device, which may cause the shear pin at the blower inlet to break.

In this way, applying a shocking load has the risk of causing a failure of the vehicle, and is not desirable from a control standpoint. Also, the auger may become clogged with snow, making it impossible to remove snow.

In view of the above points, in the present invention, control characteristics are set for each combination of travel speed stage, snow removal device speed stage, and snow removal cross-sectional area, and the basic form thereof is as shown in FIG. In FIG. 3, N. is the reference engine rotation speed for control purposes, which is set from both the viewpoint of snow removal efficiency and problems with snow removal operations such as clogged snow chute. The load on the snow removal device is light and the engine rotation speed is the reference rotation speed N.

When the HST swash plate angle θ is larger than , the HST swash plate angle θ is kept constant so as not to increase the speed more than necessary. N. to a rotational speed NL that is inappropriate for snow removal work, the HST swash plate angle θ is decreased in proportion to the decrease in engine rotational speed. K in the arithmetic expression shown in FIG. 3 is a proportionality constant. When the engine speed is below NL, the HST swash plate angle θ is kept at zero.

Switching between manual operation and automatic operation is performed by two clutches CI and C2 operated by an operator.

Since the manual clutch CI is connected to the HST operating lever 6, manual operation is the same as in the case without the control device of the present invention. Further, the automatic clutch C2 is connected to a DC motor l3 controlled by a control device.

The traveling lever position detector AI detects the setting of the traveling speed stage, and the snow removal lever position detector A2 detects the setting of the speed stage of the snow removal equipment blower, and manually inputs the information to the microcomputer 1l.
- On the other hand, information on the snow removal cross-sectional area is input from the snow removal cross-sectional area setting device IO. The microcomputer 11 selects N from pre-stored data based on the information on the travel speed stage, blower speed stage, and snow removal cross-sectional area. , NL, θ. ,K
Select to set the control characteristics that suit your work conditions.

Changes in the engine rotational speed due to changes in the load of the snow removal device are detected by the rotational speed detector A4 and input to the microcomputer 11. Microcomputer 11
calculates the HST swash plate angle θ corresponding to the engine speed input from the above set control characteristics, and calculates the servo amplifier 1
Output as the target value of 2. The servo amplifier 12 compares the target value output from the microcomputer 11 with the actual value of the I{ST swash plate angle θ detected by the angle detector A3, and drives the DC motor 13 to adjust the angle. Control θ. An outline of a series of processing in the microcomputer 11 is shown in FIG.

<Effects> As is clear from the above explanation, according to the present invention, the H
The control characteristics of the ST swash plate angle are set, and because the control characteristics do not increase the speed more than necessary even under no-load conditions, the influence of inertia of the vehicle body can be minimized, resulting in highly accurate stability. It is possible to realize controlled control, and no shocking load is applied.

Furthermore, according to the present invention, it is possible to prevent overloading of the rotary snowplow engine and the resulting clogging of the snow throwing chute, and it is also possible to remove snow efficiently, which significantly reduces the burden on the operator. can.

Furthermore, secondarily, since the operator can concentrate on turning and operating the snow throwing ute, it also contributes to the safety of snow removal work.

In addition, it is a mechanism that simply adds an automatic control system to the conventional HST control system, so even if a problem occurs with the automatic system, it can be operated manually.

[Brief explanation of the drawing]

Figure 1 is a block diagram of the power system of a rotary snowplow, Figure 2
The figure is a block diagram showing the configuration of the speed control device of the rotary snowplow according to the present invention, and FIG. 3 is a basic characteristic diagram of the control according to the present invention.
FIG. 4 is a flowchart showing an outline of a program for achieving the control of the present invention, and FIG. 5 is a snow removal amount curve diagram. 1: Engine, 2: Distributor, 3: Traveling transmission, 4: Traveling speed gear switching lever, 5: HST, 6: Operation lever,
7: Transmission for snow removal equipment, 8: Lever for switching speed level of snow removal equipment, 9: Snow removal equipment, 10: Snow removal cross-sectional area setting device, 11: Microcomputer, θ: Swash plate angle, N: Rotation speed, A1
: Travel lever position detector, A2: Snow removal lever position detector, A3: Angle detector, A4: Rotation speed detector. Applicant Toyo Yusoki Co., Ltd.

Claims (1)

[Claims] An engine (1), a distributor (2) that distributes the output of the engine (1) to the traveling device side and the snow removal device side, and is driven by the output of one of the distributors (2). HST (5) to be
A traveling transmission (3) into which the output of the HST (5) is input.
and a snow removal device transmission (7) driven by the output of the other side of the distributor (2), a travel lever position for detecting the speed gear of the travel transmission (3). a detector (A1) and the snow removal device transmission (7);
), a snow removal lever position detector (A2) that detects the speed stage of the engine (1), a rotation speed detector (A4) that detects the rotation speed (N) of the engine (1), and a travel lever position detector (A2) that detects the speed stage of the engine (1).
A1), the swash plate angle (θ) of the HST (5) is set under the following conditions ( A speed control device for a rotary snowplow, characterized in that a microcomputer (11) for automatic control is provided below (a) to (d). Condition (a) When NL≦N≦N_0, θ=θ_0-K(N_0-N) Same (b) When N>N_0, θ=θ_0 Same (c) When N<NL, θ=0 Same (d) Driving transmission (3), transmission for snow removal equipment (7)
θ_0 is decreased in approximately inverse proportion to an increase in the speed stage and an increase in the set value of the snow removal cross-sectional area setting device (10). However, K is a constant, N_0 is the reference engine speed, and NL is the engine speed that is inappropriate for snow removal work.