JP2007046389A - Snow plow - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the workability of a snow plow having an engine-driven snow removal operation part on a self-travellable frame. <P>SOLUTION: This snow plow 10 comprises an engine 14 driving the snow removal operation part 13 such as an auger installed on the frame 19, electric motors 21L, 21R changing the traveling speeds of traveling parts 11L, 11R for traveling the frame, and a control part 61 controlling the traveling speeds by linking the engine to the electric motors. When the control part receives a start command for the snow removal operation part by the operation of an auger switch 44 or a speed change command for the engine by the operation of a throttle lever 52, it maintains the controlled state of the electric motors immediately before receiving the command over a specified period of time from a time point when it receives the command. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a snowplow having a self-propelled machine body equipped with an engine-driven snow removal working unit.

Some snowplows equipped with an engine-driven snow removal unit, such as an auger type snowplow, increase the load on the snowplow operation unit depending on the running speed and work conditions. The auger type snow remover is a working machine that scrapes snow with a front auger while moving forward to remove snow. As the running speed increases, the amount of snow removed by the auger also increases. As a result, the load on the auger increases. As such an auger type snow removal machine, various types are known (see, for example, Patent Document 1-2).
Japanese Utility Model Publication No. 3-32617 JP 2002-142307 A

  The conventional auger type snowplows shown in Patent Document 1 and Patent Document 2 are such that a machine body equipped with a snow removal working part is caused to travel by a traveling part, and the snow removal working part is driven by an engine.

As an example of a conventional auger type snowplow, the conventional technique shown in Patent Document 2 will be described with reference to FIG. FIG. 10 is a schematic view of a conventional auger snowplow.
A conventional auger type snow removal machine 100 includes a snow removal working unit 103 composed of an auger 101 and a blower 102, an engine 105 that drives the snow removal working unit 103 via a clutch 104, left and right traveling units 106, 106 composed of crawlers, and a traveling unit 106. The left and right electric motors 107 and 107 that drive the motor 106, the left and right brakes 108 and 108 that brake the traveling units 106 and 106, the control unit 109 that controls the electric motors 107 and 107 and the brakes 108 and 108, and the control unit 109 Various operation members 111, 113, 114, 114 for issuing an operation signal are provided.

By operating the throttle lever 111, the opening degree of the throttle valve 112 of the engine 105 can be adjusted. As the throttle valve 112 is opened, the rotational speed of the engine 105 increases.
The control unit 109 controls the rotation direction and rotation speed of the left and right electric motors 107 and 107 according to the operation of the accelerator lever 113, and controls the left and right brakes 108 and 108 according to the operation of the speed adjustment operation levers 114 and 114. To do.
As described above, the auger type snow remover 100 is a working machine in which the snow removal working unit 103 is driven by the engine 105 and the traveling units 106 and 106 are driven by the electric motors 107 and 107.

  By operating a clutch operating member (not shown) to turn on the clutch 104, the snow removal working unit 103 can be driven by the power of the engine 105 to perform snow removal work. The rotational speed of the engine 105 decreases according to the load applied to the snow removal working unit 103. In order to maintain this rotational speed, the opening degree of the throttle valve 112 automatically increases according to the degree of decrease. The control unit 109 controls to decrease the traveling speed of the traveling units 106 and 106 by decreasing the speed of the electric motors 107 and 107 in accordance with a decrease in the rotational speed of the engine 105 or an increase in the opening degree of the throttle valve 112. To do. That is, the snow remover travels at a traveling speed corresponding to the snow removal load.

Next, characteristics of a general snowplow when the traveling units 106 and 106 are of an electric motor drive system will be described based on FIG. 11 with reference to FIG.
FIG. 11 is a characteristic diagram of a conventional snow remover, in which the horizontal axis represents elapsed time, and the characteristic is shown by associating the opening Str of the throttle valve 112 with the actual speed Tr of the electric motors 107 and 107.

  At time t11 when the clutch 104 is switched on, the snow removal working unit 103 is subjected to a very large load. As a result, the rotational speed of the engine 105 temporarily decreases rapidly and then increases. As the rotational speed of the engine 105 changes suddenly, the opening degree Str of the throttle valve 112 also changes suddenly. The control unit 109 temporarily changes the actual speed Tr of the electric motors 107 and 107 temporarily in response to a sudden change in the rotational speed of the engine 105 or a sudden change in the opening degree Str of the throttle valve 112.

  In general, since the traveling speed of the auger type snow remover 100 is low, such a change in traveling speed is not a concern at all for workers who are relatively used to snow removal work. On the other hand, for beginners who are unfamiliar with snow removal work, it is more preferable to run as stably as possible to improve workability.

  The same applies to time points t12 and t13 when the opening degree Str of the throttle valve 112 is adjusted by operating the throttle lever 111. This is because the operation of the throttle lever 111 by a beginner unfamiliar with work is not necessarily smooth.

  This invention makes it a subject to provide the technique which can improve the workability | operativity of the snowplow provided with the engine-driven snow removal operation part in the self-propelled machine body.

In the invention which concerns on Claim 1, the engine which drives snow removal operation | work parts, such as an auger with which the airframe was equipped, the electric motor which changes the travel speed of the traveling part which drive | runs an airframe, these engines and an electric motor are related. In a snowplow equipped with a controller that controls the running speed,
When the control unit receives an operation command of the snow removal working unit based on the operation or an engine speed change command, the control unit controls the control state of the electric motor immediately before receiving the command over a certain time from the time of receiving these commands. It is characterized by being configured to maintain.

  In the invention according to claim 2, in claim 1, when an input signal issued from the engine to the control unit is temporarily disturbed with an operation command of the snow removal working unit or an engine speed change command for a certain period of time. In addition, it corresponds to the time until the disturbance is eliminated.

  According to a third aspect of the present invention, in the first or second aspect, the control unit is configured to continuously control the electric motor in association with the engine when the engine is in operation. .

In the invention according to claim 1, when the operator performs an operation for operating the snow removal work unit or an operation for changing the engine speed, the control unit issues an operation command for the snow removal work unit or an engine speed change command. When received, the electric motor is controlled while maintaining the control state immediately before receiving the command for a certain time from that point.
In this way, the control unit stably controls the electric motor by ignoring signal fluctuations associated with any load fluctuations over a certain period of time from when the command is received. Therefore, temporary fluctuations in the traveling speed in the snowplow can be suppressed, and the traveling state can be made more stable. As a result, the workability of the snowplow can be further improved.

In the invention which concerns on Claim 2, when the operator performs operation which operates a snow removal operation part, or operation which changes the rotation speed of an engine, the input which an engine emits to a control part with each instruction | command at that time Since the signal was temporarily disturbed, the optimal “certain time” was set taking into consideration the time until the disturbance was resolved. This fixed time is very small.
Thus, based on the load characteristics of the snowplow and the characteristics of the engine mounted on it, a “certain time” corresponding to the time until the temporary disturbance of the input signal is eliminated is set. Only the control state immediately before receiving the command was maintained.
If the “certain time” is too short, the disturbance of the input signal has not been eliminated, and is thus affected. On the other hand, if the “certain time” is too long, the old control state is maintained even though the disturbance of the input signal is eliminated, and the response to the command is inferior.
On the other hand, in the invention according to claim 2, since the optimal “certain time” is set based on the load characteristics of the snowplow and the characteristics of the engine mounted thereon, it is possible to further stabilize the running state. In addition, it is possible to ensure sufficient response to commands.

  In the invention according to claim 3, when the engine is operating, the electric motor is continuously controlled in relation to the engine. For this reason, when the control unit receives an operation command for the snow removal working unit or an engine speed change command regardless of the load state of the engine, the control unit always operates in the control state immediately before receiving the command for a certain time from that point. The electric motor can be controlled. Therefore, it is possible to always suppress the temporary fluctuation of the traveling speed of the snowplow due to the behavior of the engine and to always stabilize the traveling state.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. “Front”, “Rear”, “Left”, “Right”, “Up”, “Down” follow the direction viewed from the operator, Fr is front, Rr is rear, Le is left, Ri is right Indicates.
FIG. 1 is a side view of a snow removal machine (work machine) according to the present invention. FIG. 2 is a schematic plan view and control system diagram of the snowplow according to the present invention.

  As shown in FIGS. 1 and 2, the snowplow 10 includes a vehicle body that includes an auger-type working unit 13 and an engine 14 that drives the working unit 13 on a traveling frame 12 that includes left and right traveling units 11L and 11R. The rear part of the frame 15 is mounted so that it can swing up and down, the front part of the vehicle body frame 15 is moved up and down by the lift drive mechanism 16, and the left and right operation handles 17L and 17R are extended from the rear part of the traveling frame 12 to the upper rear part. The operation handles 17L and 17R are provided with grips 18L and 18R at the tips of the operation handles 17L and 17R.

  Such a snow removal machine 10 is said to be an auger type snow removal machine. Hereinafter, the working unit 13 is referred to as a snow removal working unit 13. An operator can operate the snow removal machine 10 with the operation handles 17L and 17R while walking with the snow removal machine 10.

The combined structure of the traveling frame 12 and the vehicle body frame 15 forms an airframe 19. The traveling frame 12 includes left and right electric motors 21L and 21R that drive the traveling units 11L and 11R. The left and right traveling units 11L and 11R include left and right crawler belts 22L and 22R, left and right driving wheels 23L and 23R disposed at the rear as traveling wheels, and left and right rolling wheels 24L and 24R disposed at the front. .
The left crawler belt 22L can be driven via the left driving wheel 23L by the driving force of the left electric motor 21L. The right crawler belt 22R can be driven via the right drive wheel 23R by the driving force of the right electric motor 21R.

  The snow removal working unit 13 includes an auger housing 25, a blower case 26 integrated with the back surface of the auger housing 25, an auger 27 provided in the auger housing 25, a blower 28 provided in the blower case 26, and a shooter 29.

As shown in FIG. 1, the engine 14 is a snow removal drive source that drives the snow removal working unit 13 via an electromagnetic clutch 31 and a transmission mechanism 32.
The transmission mechanism 32 is a belt-type transmission mechanism that transmits power from the electromagnetic clutch 31 attached to the crankshaft 14 a of the engine 14 to the auger transmission shaft 33 using a belt. The power of the engine 14 is transmitted to the auger 27 and the blower 28 through a path of the crankshaft 14 a → the electromagnetic clutch 31 → the transmission mechanism 32 → the auger transmission shaft 33. The snow collected by the auger 27 can be blown away by the blower 28 via the shooter 29.
The auger housing 25 includes a scraper 35 and left and right sleds 36L and 36R at the rear lower end.

  The elevating drive mechanism 16 is an actuator in which a piston can advance and retreat from a cylinder. This actuator is a type of electric hydraulic cylinder in which a piston is extended and contracted by hydraulic pressure generated from a hydraulic pump (not shown) by an electric motor 16a (see FIG. 2). The electric motor 16 a is an elevating drive source that is integrated into the side of the cylinder of the elevating drive mechanism 16.

Such a snowplow 10 has a configuration in which the auger housing 25 and the blower case 26 are attached to the traveling frame 12 so as to be able to roll, and the auger housing 25 is rolled left and right (rolled) by a rolling drive mechanism 38.
More specifically, the auger transmission shaft 33 extending in the front-rear direction is rotatably supported by the auger housing 25 and the blower case 26, and the blower case 26 is attached to the front end portion of the vehicle body frame 15 so as to be rotatable left and right (rollable). is there.

  As described above, the traveling frame 12 has a configuration in which the vehicle body frame 15 is attached. For this reason, the auger housing 25 and the blower case 26 are attached to the traveling frame 12 so as to be able to roll. As a result, the auger housing 25 can be lifted and lowered with respect to the traveling frame 12.

  The rolling drive mechanism 38 is an actuator capable of moving a piston back and forth from a cylinder. This actuator is a type of electric hydraulic cylinder in which a piston is extended and contracted by hydraulic pressure generated from a hydraulic pump (not shown) by an electric motor 38a (see FIG. 2). The electric motor 38 a is a rolling drive source that is integrated into the side of the cylinder of the rolling drive mechanism 38.

  By the way, an operation unit 40, a control unit 61, and a battery 62 are arranged between the left and right operation handles 17L and 17R. Hereinafter, the operation unit 40 will be described.

  FIG. 3 is a perspective view of the operation unit according to the present invention. FIG. 4 is a plan view of the operation unit according to the present invention. 3 and 4, the operation unit 40 includes an operation box 41 provided between the left and right operation handles 17L and 17R, a travel preparation lever 42 provided on the left operation handle 17L in the vicinity of the grip 18L, and a left side. Turning control lever 43L and a right turning operation lever 43R attached to the right operation handle 17R in the vicinity of the grip 18R.

  The travel preparation lever 42 is a travel preparation member that acts on the switch 42a (see FIG. 2), and the switch 42a is turned off when the free spring shown in FIG. If the travel preparation lever 42 is grasped with the operator's left hand and lowered to the grip 18L side, the switch 42a is turned on.

The left and right turning operation levers 43L and 43R are turning operation members that are respectively operated by the hands holding the left and right grips 18L and 18R, and are mechanisms that act on the corresponding turning switches 43La and 43Ra (see FIG. 2).
When these left and right turning operation levers 43L and 43R are brought into a free state shown in the figure by the pulling action of the return spring, the turning switches 43La and 43Ra are turned off. If the operator turns the left turning lever 43L with the left hand and raises it to the grip 18L side, the left turning switch 43La is turned on. The same applies to the right turning switch 43Ra. In this way, whether or not the left and right turning operation levers 43L and 43R are being gripped can be detected by the turning switches 43La and 43Ra.

Referring to FIG. 2 as well, the operation box 41 includes a main switch 44 and an auger switch 45 (also referred to as “clutch operation switch 45”) on the back surface 41a (worker side surface).
The engine 14 can be started by turning the main switch 44 on. The auger switch 45 is a manual switch that switches the electromagnetic clutch 31 on and off, and includes, for example, a push button switch.

Further, the operation box 41 has a mode changeover switch 51, a throttle lever 52, a direction speed lever 53, a reset switch 54, an auger housing posture operation lever 55 and a shooter operation lever 56 arranged on the upper surface 41b in this order from the left side to the right side. , Which is provided.
More specifically, a directional speed lever 53 is arranged on the upper surface 41b of the operation box 41 on the left side of the vehicle width center CL, and a reset switch 54 is arranged on the right side of the vehicle width center CL.

  The mode changeover switch 51 is a manual changeover switch that switches the travel control mode in the control unit 61, and is formed of, for example, a rotary switch. It is possible to switch to the first control position P1, the second control position P2, and the third control position P3 by turning the knob 51a counterclockwise. When switching to each of these positions P1, P2, P3, the mode changeover switch 51 issues a corresponding switch signal.

  The first control position P1 is a switch position for causing the control unit 61 to perform control in the “first control mode”. The second control position P2 is a switch position for causing the control unit 61 to perform control in the “second control mode”. The third control position P3 is a switch position for causing the control unit 61 to perform control in the “third control mode”.

  The first control mode is a so-called manual mode in which control is performed manually based on the rotational speed of the engine 14. The second control mode is a so-called power mode in which the traveling speed is controlled to be gradually decreased with respect to the increase amount of the opening degree of the throttle valve 71. The third control mode is a so-called auto mode (automatic mode) in which the traveling speed is controlled so as to decrease more greatly than in the second control mode with respect to the increase amount of the opening degree of the throttle valve 71. . In the second and third control modes, the travel speed may be controlled based on the rotational speed of the engine 14 instead of the opening of the throttle valve 71.

As described above, the load control mode of the control unit 61 is changed to (1) a first manual operation mode used by an advanced user accustomed to work, and (2) a semi-automatic type used by an intermediate worker accustomed to some degree. This mode is set to three modes: a second control mode and (3) an automatic third control mode used by an unfamiliar beginner.
By appropriately selecting these modes, one snowblower 10 can be easily used from beginners to advanced workers in a work mode that is optimal for them.

  The throttle lever 52 is an operating member for controlling the opening and closing of the throttle valve 71 by controlling a control motor 72 of an electronic governor (also referred to as an electric governor). The voltage can be reciprocated in the front-rear direction, and a voltage corresponding to the position is generated by the potentiometer 52a. When the throttle lever 52 is tilted in the direction of the arrow De, the throttle valve 71 can be closed until it is fully closed, and when the throttle lever 52 is tilted in the direction of the arrow In, the throttle valve 71 can be opened until it is fully opened. As a result, the rotational speed of the engine 14 can be adjusted.

  The direction speed lever 53 is an operation member for controlling the rotation of the electric motors 21L and 21R, and details thereof will be described later (see FIG. 5).

  The reset switch 54 (auger original position automatic return switch 54) is a manual switch for returning the attitude (position) of the auger housing 25 to a preset origin, and is composed of, for example, a push button switch. Is provided.

The auger housing posture operation lever 55 is an operation member for changing the posture of the auger housing 25. In other words, the auger housing posture operation lever 55 is an operation member for operating the elevating drive mechanism 16 and the rolling drive mechanism 38 to elevate and roll the auger housing 25 in accordance with the snow surface when the auger 27 performs snow removal work. . When the auger housing posture operation lever 55 is swung to the front side Frs, the rear side Rrs, the left side Les, and the right side Ris, the corresponding switches can be turned on.
The shooter operating lever 56 is an operating member for changing the direction of the shooter 29 (see FIG. 1).

FIG. 5 is an operation explanatory view of the directional speed lever employed in the present invention.
As shown in FIG. 5, the directional speed lever 53 (also referred to as “forward / reverse speed adjustment lever 53”) can be reciprocated back and forth as indicated by arrows Ad and Ba by the operator's hand, and from the “neutral range”. The snowplow 10 (see FIG. 1) can be moved forward by tilting it toward the “forward” side, and in the “forward” region, speed control can be performed so that Lf is forward at low speed and Hf is forward at high speed. Similarly, if the snowplow 10 can be moved backward from the “neutral range” to the “reverse” side, the speed control can also be performed so that Lr is low-speed reverse and Hr is high-speed reverse in the “reverse” region. Yes.

  In this example, as indicated at the left end of the figure, the potentiometer 53a (see FIG. 2) is set so that the maximum reverse speed is 0 V (volt), the maximum forward speed is 5 V, and the neutral range is 2.3 V to 2.7 V. ) To generate a voltage according to the position. The front / rear direction and the high / low speed control can be set with one lever, so the direction speed lever 53 is named.

  Next, the control system of the snow removal machine 10 will be described with reference to FIG. The control system of the snowplow 10 is centralized in the control unit 61. The control unit 61 has a configuration in which a memory 63 is built in, and various information stored in the memory 63 is appropriately read and controlled.

First, the operation of the system of the snow removal working unit 13 will be described.
The intake system of the engine 14 has a configuration in which the throttle valve 71 is controlled to open and close by the control motor 72 and the choke valve 73 is controlled to open and close by the control motor 74. That is, the control motor 72 of the electronic governor 65 automatically adjusts the opening degree of the throttle valve 71 based on the signal from the control unit 61, and the control motor 74 of the electronic governor 65 adjusts the opening degree of the choke valve 73. It is a configuration that automatically adjusts.

The opening of the throttle valve 71 is detected by a throttle position sensor 75, the opening of the choke valve 73 is detected by a choke position sensor 76, and these detection signals are sent to the control unit 61.
The rotation speed (rotation speed) of the engine 14 is detected by the engine rotation sensor 77 and a detection signal is issued to the control unit 61.

  The generator 81 is rotated by a part of the output of the engine 14, and the obtained electric power is supplied to the battery 62 and also supplied to the left and right electric motors 21L and 21R and other electrical components. The remaining output of the engine 14 is used for the rotation of the auger 27 and the blower 28.

  By grasping the travel preparation lever 42 and operating the auger switch 45, the electromagnetic clutch 31 can be connected (turned on), and the auger 27 and the blower 28 can be rotated by the power of the engine 14. The electromagnetic clutch 31 can be turned off by turning the traveling preparation lever 42 free or operating the auger switch 45.

Next, the operation of the traveling units 11L and 11R will be described.
The snow remover 10 of the present invention includes left and right electromagnetic brakes 82L and 82R as brakes corresponding to parking brakes for ordinary vehicles. Specifically, the left and right electric motors 21L and 21R are braked by the left and right electromagnetic brakes 82L and 82R. These electromagnetic brakes 82L and 82R are in a brake state (on state) under the control of the control unit 61 during parking. Therefore, the electromagnetic brakes 82L and 82R are released by the following procedure.

  When the two conditions of the main switch 44 being in the ON position and the travel preparation lever 42 being gripped are satisfied and the directional speed lever 53 is switched to forward or reverse, the electromagnetic brakes 82L and 82R are in the OFF state. become.

  The control unit 61 that has obtained the position information of the directional speed lever 53 from the potentiometer 53a rotates the left and right electric motors 21L and 21R via the left and right motor drivers 84L and 84R, and rotates the rotation speed (the number of rotations) of the electric motors 21L and 21R. ) Is detected by the motor rotation sensors 83L and 83R, and feedback control is executed based on the detection signals so that the rotation speed becomes a predetermined value. As a result, the left and right drive wheels 21L, 21R rotate in a desired direction at a predetermined speed and enter a traveling state.

  Braking while driving is performed according to the following procedure. Motor drivers 84L and 84R include regenerative brake circuits 85L and 85R and short-circuit brake circuits 86L and 86R. The short circuit brake circuits 86L and 86R are brake means.

While holding the left turning lever 43L and turning on the left turning switch 43La, the control unit 61 activates the left regenerative brake circuit 85L based on the switch-on switch signal, and the left electric motor Decrease the speed of 21L.
While gripping the right turning operation lever 43R and turning on the right turning switch 43Ra, the control unit 61 operates the right regenerative brake circuit 85R based on the switch-on switch signal, and the right electric motor Decrease the speed of 21R.
That is, the snowplow 10 can be turned left only while the left turning lever 43L is being gripped. Further, the snowplow 10 can be turned to the right only while holding the right turning operation lever 43R.

  The travel can be stopped by either (1) releasing the travel preparation lever 42, (2) returning the main switch 44 to the OFF position, or (3) returning the direction speed lever 53 to the neutral position. it can.

  By swinging the auger housing posture operation lever 55 back and forth, the electric motor 16a rotates forward and backward, and the piston of the elevating drive mechanism 16 expands and contracts. As a result, the auger housing 25 and the blower case 26 move up and down. The elevation position of the auger housing 25 is detected by a height position sensor 87 (vertical movement detection unit 87), and a detection signal is issued to the control unit 61.

  By swinging the auger housing posture operation lever 55 left and right, the electric motor 38a rotates in the forward direction, and the piston of the rolling drive mechanism 38 is expanded and contracted. As a result, the auger housing 25 and the blower case 26 roll left and right. The rolling position of the auger housing 25 is detected by a rolling position sensor 88 (left / right tilt detection unit 88), and the detection signal is sent to the control unit 61.

  Next, a control flow when the control unit 61 shown in FIG. 2 is a microcomputer will be described with reference to FIGS. In the figure, STxx indicates a step number. Step numbers that are not specifically described proceed in numerical order. Hereinafter, a description will be given with reference to FIGS.

FIG. 6 is a control flowchart (No. 1) of the control unit according to the present invention.
ST01: The engine 14 is started by starting the main switch 44.
ST02: The operation amount Sr of the throttle lever 52 is read. As for the operation amount Sr, a voltage corresponding to the position of the throttle lever 52 may be detected by the potentiometer 52a.
ST03: Replace the old manipulated variable Sb value of the throttle lever 52 with the new manipulated variable Sr value and write it to the memory 63. That is, the operation amount Sr read in ST02 is set as the value of the old operation amount Sb.

ST04: The operation amount Rop of the direction speed lever 53 is read. Regarding the operation amount Rop, a voltage corresponding to the position of the directional speed lever 53 may be detected by the potentiometer 53a.
ST05: The target speed Ts of the electric motors 21L and 21R is obtained from the operation amount Rop of the directional speed lever 53.
ST06: The opening degree Str of the throttle valve 71 is measured. The opening degree Str may be measured by the throttle position sensor 75.

ST07: Based on the correction map (see FIG. 8), the deceleration correction coefficient Rd of the electric motors 21L, 21R with respect to the opening degree Str of the throttle valve 71 at that time is obtained. Details of the correction map will be described later.
ST08: The target speed Ts is corrected by the deceleration correction coefficient Rd. That is, the original target speed Ts obtained from the operation amount Rop of the directional speed lever 53 is corrected by multiplying by the deceleration correction coefficient Rd, and this corrected value is set as a new target speed Ts (Ts = Ts × Rd). .
ST09: The actual speed Tr of the electric motors 21L and 21R (actual rotational speed Tr; hereinafter referred to as “actual speed Tr”) is measured. The actual speed Tr may be measured by the motor rotation sensors 83L and 83R, for example.

ST10: After the forward control of the electric motors 21L and 21R is executed by PID control so that the actual speed Tr of the electric motors 21L and 21R becomes the corrected target speed Ts, the process proceeds to ST11 in FIG. The traveling units 11L and 11R travel forward.
In this way, by constantly measuring the change in the opening Str of the throttle valve 71 and correcting the target speed Ts in accordance with the opening Str, the speeds of the electric motors 21L and 21R are controlled, whereby the traveling units 11L and 11R. Control the running speed of the car.

FIG. 7 is a control flowchart (part 2) of the control unit according to the present invention.
ST11: The switch signal of the auger switch 45 is read.
ST12: It is checked whether or not the auger switch 45 is changed from OFF to ON. If NO, the process proceeds to ST13, and if YES, the process proceeds to ST17. When the on-operation of the auger switch 45 is started, the switch signal is reversed from off to on, so that it is determined as YES if an operation command for the snow removal working unit 13 based on the operation is received. That is, the operation command of the snow removal work unit 13 based on the operation is received only when the on operation is started. Although not shown, in the case of YES, the snow removal working unit 13 starts operating when the electromagnetic clutch 31 is turned on from off.

ST13: It is checked whether or not the auger switch 45 is changed from on to off. If NO, the process proceeds to ST14, and if YES, the process proceeds to ST17. When the auger switch 45 is turned off, the switch signal is reversed from on to off. Therefore, it is determined as YES if a stop command for the snow removal working unit 13 based on the operation is received. That is, the stop command for the snow removal work unit 13 based on the operation is received only when the off operation is started. Although not shown, in the case of YES, the operation of the snow removal working unit 13 is stopped when the electromagnetic clutch 31 is turned off from on.
ST14: The operation amount Sr of the throttle lever 52 is read. As for the operation amount Sr, a voltage corresponding to the position of the throttle lever 52 may be detected by the potentiometer 52a.

ST15: It is checked whether or not the operation amount Sr of the throttle lever 52 is inconsistent with the old operation amount Sb. If YES, the process proceeds to ST16, and if NO, the process proceeds to ST21.
When the new operation amount Sr changes with respect to the previous previous operation amount Sb, it is determined as YES because it receives a command to change the rotational speed of the engine 14. That is, it is determined that the throttle lever 52 has been operated.

  If NO is determined here, at the present time, the operation command of the snow removal working unit 13 based on the operation is not received (ST12), the stop command is not received (ST13), and the rotational speed of the engine 14 is not received. Since no change command has been received (ST15), it is determined that there is no temporary disturbance in the input signal issued from the engine 14 to the control unit 61 in accordance with these commands.

ST16: Replace the old operation amount Sb value of the throttle lever 52 with the new operation amount Sr value and write it to the memory 63. That is, the operation amount Sr read in ST14 is set as the value of the old operation amount Sb.
ST17: The count time Tc of the timer built in the control unit 61 is set to 0, and the timer is started.
ST18: Forward control of the electric motors 21L and 21R is executed by PID control so that the actual speed Tr of the electric motors 21L and 21R becomes the corrected target speed Ts. That is, the control state executed in ST10 is continued immediately before the determination of YES in ST12, ST13, or ST15.

ST19: Check whether the count time Tc (elapsed time Tc) has passed a predetermined reference time Ts. If NO, the process returns to ST18. If YES, the process proceeds to ST20.
That is, by repeating ST18 and ST19 until YES, the control state immediately before YES is determined in ST12, ST13 or ST15 is maintained, and the electric motors 21L and 21R are controlled.
Note that ST18 may be abolished if the same effect can be obtained without having ST18. In that case, only ST19 is repeated until it becomes YES.

ST20: The timer is stopped.
ST21: It is checked whether or not the engine 14 is operating. If YES, the process returns to ST04 in FIG. 6, and if NO, the control flow is completed. That is, in the case of YES, the electric motors 21L and 21R are controlled in association with the engine 14 by returning to ST04. For example, a determination of YES is made when the rotation speed of the engine 14 measured by the engine rotation sensor 77 exceeds a reference value.

  As is apparent from the above description, the configuration composed of the set of ST04 to ST10 described above is a load for executing the rotation control of the electric motors 21L and 21R based on the operation amount Rop of the directional speed lever 53 and the opening degree Str of the throttle valve 71. It forms the control unit. Thus, the load control unit always detects the amount of change in the operation amount Rop and the opening degree Str, and controls the traveling speed according to the amount of change.

  Furthermore, the traveling surface on which the snow removal machine 10 travels has irregularities and slopes. When the snowplow 10 travels, traveling resistance corresponding to the road surface condition is generated even when the snow removal work unit 13 is stopped, that is, during non-working. In the present invention, in consideration of such a traveling situation, the snow remover 10 is made to travel more smoothly. For this reason, when the engine 14 is operating, the control unit 61 controls the electric motors 21L and 21R in relation to the engine 14 even when the snow removal work unit 13 is stopped (ST04 to ST10). It was.

  The signal of the throttle valve opening Str is used as an input signal from the engine 14 to the controller 61. Note that the input signal issued from the engine 14 to the control unit 61 may be a signal indicating the rotational speed of the engine 14.

  In the control flow, the drive control method for the left and right electric motors 21L, 21R is, for example, a pulse width modulation method (PWM method) for supplying a pulse voltage to the motor terminals. In response to the control signal of the control unit 61, the motor drivers 84L and 84R can control the rotation of the electric motors 21L and 21R by issuing a pulse signal whose pulse width is controlled.

Here, the correction map used in ST07 will be described with reference to FIG.
FIG. 8 is an explanatory view of a correction map according to the present invention. The vertical axis on the left side of the figure is the throttle valve opening degree Str (%), and the right vertical axis is the deceleration correction coefficient Rd of the electric motor. The correction map which obtains the deceleration correction coefficient Rd corresponding to degree Str is shown. The scale of the opening degree Str is 0% at the bottom and 100% at the top. The scale of the deceleration correction coefficient Rd is a value with 0.0 on the bottom and 1.0 on the top.

  The solid line rising upward in the figure is the valve opening characteristic line ST, which is a straight line indicating that the opening degree Str of the throttle valve changes in the range of 0 to 100%. The solid line descending to the right is a deceleration characteristic line RT, which is a straight line indicating that the deceleration correction coefficient Rd of the electric motor changes in the range of 1.0 to Rd1. Rd1 is the minimum value of the deceleration characteristic line RT and is a small value close to zero.

  When the opening Str is Str, for example, a horizontal line passing through the Str intersects the valve opening characteristic line ST at an intersection P1, and a vertical line extends vertically from the intersection P1 to reduce deceleration characteristics. Intersects line RT at intersection P2. The value of the deceleration correction coefficient Rd at this intersection P2 is Rd2. That is, the value of the deceleration correction coefficient corresponding to the throttle valve opening Str is Rd2.

Similarly, when Str = 0%, Rd = 1.0, and when Str = 100%, Rd = Rd1. That is, the deceleration correction coefficient Rd is closer to 1 as the opening degree Str of the throttle valve is smaller, and closer to 0 as the opening degree Str is larger.
Thus, the correction map is Rd1 in which the deceleration correction coefficient Rd of the electric motor decreases as the throttle valve opening degree Str increases, and the deceleration correction coefficient when fully opened (Str = 100%) is greater than zero. It has the characteristic of being.

Next, the characteristics of the snowplow 10 having the above configuration will be described with reference to FIG. 9 with reference to FIG.
FIG. 9 is a characteristic diagram of the snowplow according to the present invention. The horizontal axis represents elapsed time, and the characteristic is shown by associating the opening Str of the throttle valve 71 with the actual speed Tr of the electric motors 21L and 21R. is there.

At the time t1 when the auger switch 45 is switched on, that is, at the time t1 when the control unit 61 receives an operation command for the snow removal work unit 13, a very large load is applied to the snow removal work unit 13 temporarily. As a result, the rotational speed of the engine 14 temporarily increases rapidly and then increases. As the rotational speed of the engine 14 changes suddenly, the opening degree Str of the throttle valve 71 also changes suddenly.
Similarly, at the time t2 and t3 when the opening degree Str of the throttle valve 71 is adjusted by the operation of the throttle lever 52, that is, at the time t2 and t3 when the control unit 61 receives the rotation speed change command of the engine 14, The opening degree Str of the valve 71 also changes suddenly temporarily.

  On the other hand, the control unit 61 maintains the control state immediately before receiving the command over a certain time Ts (reference time Ts) from these time points t1, t2 or t3, and sets the actual speed Tr of the electric motors 21L and 21R. Control. That is, although the opening degree Str of the throttle valve 71 is temporarily disturbed with each command, the control unit 61 ignores the fluctuation over a certain time Ts until the disturbance is eliminated, and the electric motors 21L and 21R. The actual speed Tr is controlled stably.

The above description is summarized as follows.
As shown in FIGS. 2 and 6 to 8, the snow removal machine 10 according to the present invention includes an engine 14 that drives a snow removal working unit 13 such as an auger provided in the body 19, and traveling units 11 </ b> L and 11 </ b> R that cause the body 19 to travel. Electric motors 21L and 21R that vary the traveling speed of the motor, and a controller 61 that controls the traveling speed in association with the engine 14 and the electric motors 21L and 21R.

  The control unit 61 receives an operation command for the snow removal working unit 13 based on the operation (ST12), receives a stop command (ST13), or receives a rotation speed change command for the engine 14 (ST15). The control state of the electric motors 21L and 21R immediately before receiving the command is maintained (ST18) over a certain reference time Ts, that is, a certain time Ts from the time when the command is received (ST18). Features.

  According to the present invention, the control unit 61 receives an operation command and a stop command for the snow removal work unit 13 by performing an operation for operating the snow removal work unit 13 or an operation for changing the rotational speed of the engine 14 according to the present invention. When the engine speed change command is received, the electric motors 21L and 21R are controlled while maintaining the control state immediately before receiving the command for a certain time Ts from that time.

  As described above, the control unit 61 stably ignores the signal fluctuations accompanying the load fluctuations over a certain time Ts from the time when the command is received, and stably operates the electric motors 21L and 21R. Control. Therefore, temporary fluctuations in the traveling speed in the snow removal machine 10 can be suppressed, and the traveling state can be made more stable. As a result, the workability of the snow removal machine 10 can be further improved.

  In the present invention, when the input signal issued from the engine 14 to the control unit 61 is temporarily disturbed in accordance with an operation command, a stop command, or an engine speed change command of the snow removal working unit 13 in a certain time Ts, It corresponds to the time until the disturbance is eliminated.

When an operator performs an operation for operating / stopping the snow removal working unit 13 or an operation for changing the rotational speed of the engine 14, an input signal issued from the engine 14 to the control unit 61 is accompanied by each command at that time. Since it is temporarily disturbed, the optimum “certain time Ts” is set by fully considering the time until the disorder is resolved. This fixed time Ts can be very small.
In this way, based on the load characteristics of the snowplow 10 and the characteristics of the engine 14 mounted thereon, the “constant time Ts” corresponding to the time until the temporary disturbance of the input signal is eliminated is set. The control state immediately before receiving the command is maintained for a certain time Ts.

If the “certain time Ts” is too short, the disturbance of the input signal has not been eliminated, and is thus affected. On the other hand, if the “certain time Ts” is too long, the old control state is maintained even though the disturbance of the input signal is eliminated, and the response to the command is inferior.
On the other hand, in the present invention, since the optimum “fixed time Ts” is set based on the load characteristics of the snowplow 10 and the characteristics of the engine 14 mounted on the load characteristics, the running state can be further stabilized. At the same time, sufficient response to the command can be secured.

  Further, the control unit 61 is configured to continuously control the electric motors 21L and 21R in relation to the engine 14 (ST04 to ST10) when the engine 14 is in operation (ST21). .

  Therefore, regardless of the load state of the engine 14, the control unit 61 receives an operation command for the snow removal work unit 13 (ST12), receives a stop command (ST13), or issues a rotation speed change command for the engine 14. When received (ST15), the electric motors 21L and 21R can be controlled (ST18) in a control state immediately before receiving the command, always over a certain time Ts from that point (ST17, ST19). Therefore, temporary fluctuations in the traveling speed of the snowplow 10 due to the behavior of the engine 14 can always be suppressed, and the traveling state can be always stabilized.

  As described above, the configuration of the control flow of the control unit 61 described based on FIGS. 6 to 8 is, for example, the second control mode when the mode switch 51 is switched to the second control position P2, or the third control position P3. It is optimal to apply to the third control mode when switching to.

  In the present embodiment, the snow removal machine 10 is not limited to the auger type snow removal machine as long as the load applied to the snow removal work unit 13 increases according to the traveling speed.

Further, the driving source of the traveling units 11L and 11R is not limited to the electric motors 21L and 21R. For example, the engine 14 is used as a driving source, and the power of the engine 14 is transmitted to the traveling units 11L and 11R via a hydrostatic continuously variable transmission. The structure which transmits motive power to 11R may be sufficient. The hydrostatic continuously variable transmission is a well-known continuously variable transmission that can independently rotate the left and right output shafts forward, reverse, and stop with respect to power taken from an input shaft. In the hydrostatic continuously variable transmission, for example, the rotation of the left and right output shafts may be shifted by changing the swash plate on the pump side with the electric motor 21L or 21R.
That is, the electric motors 21L and 21R may be configured to vary the traveling speed of the traveling units 11L and 11R.

  The snow removal machine 10 of the present invention drives the snow removal working unit 13 with the engine 14 and also varies the traveling speed of the traveling units 11L and 11R with the electric motors 21L and 21R, so that the engine 14 and the electric motors 21L and 21R are related. The self-propelled working machine increases the load applied to the snow removal working unit 13 in accordance with the traveling speed. Such a self-propelled working machine is suitable for an auger-type snow removal machine that scrapes and removes snow with a front auger 27 while traveling forward.

1 is a side view of a snowplow according to the present invention. It is a typical top view and control system diagram of the snowplow according to the present invention. It is a perspective view of the operation part which concerns on this invention. It is a top view of the operation part which concerns on this invention. It is action | operation explanatory drawing of the direction speed lever employ | adopted by this invention. It is a control flowchart (the 1) of the control part concerning the present invention. It is a control flowchart (the 2) of the control part which concerns on this invention. It is explanatory drawing of the correction map which concerns on this invention. It is a characteristic view of the snowplow according to the present invention. It is a schematic diagram of the conventional auger type snow removal machine. It is a characteristic view of the conventional snow remover.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Snow removal machine, 11L, 11R ... Traveling part, 13 ... Snow removal working part, 14 ... Engine, 19 ... Airframe, 21L, 21R ... Electric motor, 27 ... Auger, 28 ... Blower, 45 ... Auger switch, 52 ... Throttle lever , 61: control unit, 71: throttle valve, Str: opening of the throttle valve, Ts: fixed time (reference time).

Claims (3)

An engine that drives a snow removal work section such as an auger provided in the airframe, an electric motor that varies the travel speed of the travel section that travels the airframe, and a control that controls the travel speed in association with the engine and the electric motor. In a snowblower equipped with a
When the control unit receives an operation command of the snow removal working unit or an engine speed change command based on an operation, the electric motor immediately before receiving the command for a certain period of time after receiving the command A snow remover configured to maintain the control state of   For a certain period of time, when the input signal issued from the engine to the control unit is temporarily disturbed in accordance with the operation command of the snow removal working unit or the engine speed change command, the disturbance is eliminated. The snow remover according to claim 1, which corresponds to a time until. The snow removal machine according to claim 1 or 2, wherein the control unit is configured to continuously control the electric motor in relation to the engine when the engine is in operation.

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