CN100566126C - Walk-behind self-propelled snow removing machine - Google Patents

Abstract

A kind of walk-behind self-propelled snow removing machine comprises: be arranged on snow removal unit ability of posture control part on this operation part in a side of operation part; Be installed in the walking preparation bar that a safety pole on the operating handle constitutes by opposite side in this operation part; Be arranged on this operation part and mode selection switch before bar is prepared in this walking, this mode selection switch is used for selecting a kind of operator scheme in plurality of optional snow removing operator scheme, and this multiple snow removing operator scheme is based on this body speed of travel, engine speed and throttle opening and predefined in control unit; Described multiple snow removing operator scheme comprises: thus by operator's manual operation carry out control first control model, carry out second control model that the speed of travel that control makes body moderately reduces with respect to the increase of throttle opening and the speed of travel that makes described body to increase the 3rd control mould that reduces with respect to throttle opening biglyyer than the degree under second control model.

Description

Walking self-propelled snow plow

technical field

The present invention relates to a walk-behind self-propelled snow removal machine having: an engine-driven snow removal unit provided at the front end of a body; unit; and left and right operating handles extending rearward from the body so that an operator can control operations of the snow removing unit and the walking unit by grasping the handles by hand while walking behind the snow blower.

Background technique

A pedestrian-type self-propelled snow blower of a related type is known as a disclosure in Japanese Patent Publication (JP-A) No. 2000-54335. As shown in FIG. 27, the disclosed snow blower 220 includes an operating portion 221 mounted to extend between left and right handles 222L and 222R. The operating part 221 includes an operating panel, which is provided with: a throttle lever 223 for adjustably controlling the throttle opening of the engine 224; Speed control lever 225; And multifunctional lever 227, this multifunctional lever 227 is used for controlling the rolling and pivoting of snow removal unit 228 and is arranged on the left and right clutch (not shown) between engine 224 and left and right traveling unit 229L and 229R shown) switching operation (engagement and disengagement).

During snow removal operations, the load on snow removal unit 228 may vary due to, for example, the physical properties and characteristics of the snow to be removed. For example, when the load on the snow removal unit 228 increases, the rotation speed of the engine 224 and the travel speed of the body 226 are reduced. In this case, the operator may know that the load on the snow removal unit 228 has increased by sensing a decrease in the walking speed of the snow removal machine 220 . To avoid undue reductions in road speed (which would result in inefficient snow removal operations), the operator, upon sensing a reduction in road speed, may shift the throttle lever in a direction that increases the throttle opening of the engine 224, thereby increasing engine speed (engine power). Since switching of the throttle control lever depending on the sensing ability of the operator occurs frequently during the snow removal operation, the efficiency and quality of completion of the snow removal operation largely depends on the skill of the operator.

According to improvements proposed heretofore, the engine speed and the travel speed of the snow blower are controlled to vary as the load on the snow removal unit changes. The proposed improvements are not completely satisfactory in terms of the operability and user convenience of the operating part and the efficiency of the snow removal operation. Typical examples of this prior improvement are disclosed in Japanese Utility Model Laid-Open Publication (JP-U-A) No. 3-32617 and Japanese Patent Laid-Open Publication (JP-A) No. 2005-42310.

Contents of the invention

It is therefore an object of the present invention to provide a walk-behind self-propelled snow blower that is easy to use for all operators regardless of their skill level, is highly user-friendly and can be realized with a good quality of finish Efficient snow removal operations.

According to the present invention, there is provided a walk-type self-propelled snow removal machine, which includes: a body with a front end and a rear end; a snow removal unit disposed at the front end of the body for performing snow removal operations; disposed on the body for An engine driving the snow removal unit; a walking unit arranged on the body and driven to make the body walk; left and right operating handles extending upward and backward from the rear of the body, the operation A handle is arranged on each side of the body longitudinal centerline; a control unit for controlling the operation of the snow removal unit and the walking unit; installed to extend between the left and right operating handles for use by the operator an operation part that operates to provide instructions to the control unit; a snow removal unit posture control member provided on the operation part on one side of the longitudinal centerline of the body, the control part being operated by an operator to control the The attitude of the snow removal unit; the walking preparation lever pivotally mounted on one of the left and right side operating handles on the other side of the longitudinal centerline of the body, the walking preparation lever for being grasped by the operator to make The body is in a state of preparing to walk, and when the walking preparation lever is released by the operator, the body will automatically be in a state of being unable to walk; and the mode selection is arranged on the operating part and before the walking preparation lever a switch for operation by an operator to select a snow removal mode of operation from a plurality of selectable snow removal modes of operation based on a combination of the vehicle's travel speed, engine speed, and engine speed The relative throttle opening is pre-set in the control unit; the plurality of selectable snow plowing operation modes include: a first control mode in which control is performed manually by an operator based on engine speed; a second control mode , wherein control is performed so that the walking speed of the body is moderately decreased with respect to an increase in the throttle opening degree; and a third control mode, wherein control is performed so that the walking speed of the body is reduced more than that in the second control mode The degree obtained under the greater degree decreases with respect to the increase in throttle opening. This first control mode is the "manual" control mode and thus is most suitable for use by a skilled operator. This second control mode is the "power" and "semi-automatic" control modes and thus is most suitable for use by semi-skilled operators. This third control mode is an "automatic" control mode and thus best suited for use by unskilled operators.

With the mode selection switch thus arranged, it is possible to set various selectable snow removal operation modes most suitable for skilled operators, semi-skilled operators, and unskilled operators. Therefore, this snow blower is highly user-friendly.

The snow blower may further include an adjustment member disposed on the operation part near the mode selection switch, the adjustment member being operated by an operator to adjust engine power and a snow throwing distance of the snow removal unit. By arranging the adjustment member and the mode selection switch close to each other in this way, the respective functions of the adjustment member and the mode selection switch can be easily interlocked to thereby improve the operability of the operation portion. This increases the efficiency of snow removal operations. In a preferred form of the invention, said adjusting member is arranged between said mode selection switch and a walking ready lever as seen in the longitudinal direction of said body.

In a preferred form, the first control mode is set such that the rate of decrease in the walking speed of the body is set to increase as the engine speed decreases. The second control mode is set such that the rate of decrease of the walking speed of the body (which increases as the throttle opening increases) is set such that the rate of decrease within the first throttle opening range is less than In the second throttle opening range, the first throttle opening range is defined between a fully closed throttle position and a first intermediate position of partial opening, the first intermediate position of partial opening being set at the fully closed throttle position Between the first intermediate position and the fully open position, the second throttle opening range is defined between the first intermediate position and the fully open throttle position. The third control mode is set such that the rate of decrease of the walking speed of the body (which increases as the throttle opening increases) is set such that the rate of decrease is greater than In a second throttle opening range, the first throttle opening range is defined between a fully closed throttle position and a second intermediate partially open position disposed in the fully closed position and a fully open throttle position, the second throttle opening range is defined between the second intermediate position and the fully open throttle position.

When used by a skilled operator, the first control mode may allow the operator greater freedom in operating the snow blower. When used by a semi-skilled operator, the second control mode enables quick and efficient snow removal operations. Even when used by an unskilled operator, said third control mode enables the unskilled operator to perform the snow removal operation with the greatest ease and with a good quality of finish.

The walking self-propelled snow blower may further comprise a battery for supplying power to the walking unit, in which case the plurality of selectable snow removal operating modes selectable by a mode selection switch preferably includes a fourth control mode, Control is performed in the control mode to operate the traveling unit using only electric power supplied from a battery when the engine is in an off state. The fourth control mode, when selected, results in lower fuel costs, longer engine life and quieter travel of the snow blower.

In a preferred form of the invention, the control unit has the function to activate all electrical systems of the snow blower only when the main switch of the snow blower has been switched to the ON position and the mode of operation has been approved by the operator When the manual operation of the mode selection switch is switched to the fourth control mode, the engine is turned off or the engine is kept in the off state. The control unit may also have a function of automatically starting the engine when the operation mode is switched from the fourth control mode to another control mode by the mode selection switch. Preferably, the main switch also has a start position that instructs the control unit to start the engine, and wherein the control unit also has a mode of operation that is switched from the fourth control mode to another control mode only by the mode selection switch and The function of starting the engine when the main switch has been switched to the start position. With the main switch thus arranged, the operator can certainly know the mode change from this fourth control mode to another control mode.

Preferably, the operation part includes: a direction speed control lever manually operable to reciprocate between a forward walking position and a backward walking position through a neutral position so as to adjustably set the walking direction and the walking direction of the body. speed; and a manually operable drive command switch to provide commands to said control unit to enable power to be delivered from the engine to the snow removal unit. The mode select switch is manually operable to select an automatic position to perform automatic setting of the engine speed and body travel speed, or a manual position to allow an operator to perform manual settings of the engine speed and body travel speed. The control unit has the function that if the mode selection switch is set to the automatic position, the direction speed control lever has been shifted from the neutral position toward the forward travel position and the drive command switch is in the ON state, then Increase engine speed to snow removal operating range.

By setting the mode selection switch at the automatic position to perform automatic control of the engine speed and body walking speed, when the drive command switch is activated by setting the direction speed control lever at the forward walking position, the engine speed will automatically increase. Large enough for snow removal operations. Accordingly, the snow blower 10 begins to travel forward while driving the snow removal unit with the engine operating at a higher speed within the snow removal operating range. In this case, however, since the control does not require the operator to perform a separate operation to switch the throttle lever in the direction of increasing the throttle opening, the snow removal operation can be performed with improved efficiency.

In a preferred form of the invention, the function of the control unit to increase the engine speed to the snow removal operating range is inhibited if the operator releases the ready-to-go lever. By thus disabling the engine speed increasing function of the control unit 61, fuel costs can be saved and the service life of the engine can be extended.

Description of drawings

Some preferred embodiments of the invention will be described in detail below, by way of example only, with reference to the accompanying drawings, in which:

Fig. 1 is a side view of a walking type self-propelled snow blower according to an embodiment of the present invention;

Fig. 2 is a schematic top view of the snow blower, showing the general structure of the control system;

Fig. 3 is a perspective view showing an operating portion of the snow blower;

Fig. 4 is a top view of the operating part;

Fig. 5 is a schematic diagram showing the operation of the direction speed control lever of the operation section;

6 is a flowchart representing a main control program executed in the control unit of the snow blower for controlling the operation of an engine and a motor for respectively driving the snow removal unit and the traveling unit of the snow blower;

FIG. 7 is a flowchart representing a subroutine executed to realize the first control mode shown in FIG. 6;

FIG. 8 is a view showing a load control map used in the first control mode;

FIG. 9 is a flowchart representing a subroutine executed to realize the second control mode shown in FIG. 6;

Fig. 10 is similar to Fig. 8 and is a view showing a load control map used in the second control mode;

FIG. 11 is a flowchart representing a subroutine executed to realize the third control mode shown in FIG. 6;

Fig. 12 is similar to Fig. 8 and is a view showing a load control map used in the third control mode;

13A to 13C are perspective views representing the sequence of operations to be completed by an operator to place the snow blower in a ready-to-go condition;

14A to 14C are perspective views representing the sequence of operations to be completed by an operator to cause the snow blower to begin snow removal operations;

15A to 15C are perspective views showing various operations performed by the operator to control the posture of the snow blower including the ejector;

16A to 16C are perspective views showing various operations performed by the operator to change the engine speed and the direction of travel of the snow blower;

Fig. 17 is a view similar to Fig. 3, showing an operation part according to a modified example of the present invention;

Fig. 18 is a plan view of the operating part of the modification;

FIG. 19 is a flow chart showing a main control program executed in the control unit based on a switch signal from a mode selection switch provided on the operation portion shown in FIG. 17;

FIG. 20 is a flowchart representing a subroutine executed to realize the fourth control mode shown in FIG. 19;

FIG. 21 is a flowchart representing a modification subroutine executed to realize the fourth control mode shown in FIG. 19;

Figure 22 is a view similar to Figure 2 but showing a modified form of the control system;

Fig. 23 is a flowchart representing a control program executed in the control unit to perform snow removal operations according to three different control modes of the present invention;

24 is a flowchart representing a control program executed in the control unit to continuously monitor the ON/OFF state of an augor switch of the snow blower;

25 is a flow chart representing a control routine executed within the control unit to continuously monitor the state of the snow plow's travel ready lever;

Figure 26 is a flowchart similar to the flowchart shown in Figure 23, representing a modified control program according to the present invention; and

Fig. 27 is a schematic top view of a conventional snow blower.

Detailed ways

Referring now to the drawings and in particular to FIG. 1 , a snow blower 10 according to an embodiment of the present invention is shown in left side view. The snow blower 10 is a so-called walking type self-propelled type, which includes a walking frame 12 equipped with left and right walking units 11L and 11R, a main body frame 15 equipped with a snow removal unit 13 and an internal combustion engine 14, and a main frame 15 from the rear of the main body frame 15. Left and right operating handles 17L and 17R extending backward and upward. The main body frame 15 has a rear end that is pivotably connected to the walking frame 12, and a front end that is adapted to move up and down by the pivot drive mechanism 16, so that when the pivot drive mechanism 16 is actuated, the The main body frame 15 including the snow removal unit 13 pivotally moves up and down around the rear end portion of the main body frame 15 . The operating handles 17L and 17R have left and right handles 18L and 18R at their distal or free ends for gripping by the operator. During the snow removal operation, the operator manipulates operating members (described later) in the operation portion while walking behind the snow remover, so as to control the operations of the snow removal unit 13 and the walking units 11L, 11R.

The walking frame 12 and the main body frame 15 together form a machine body 19 . As shown in FIGS. 1 and 2, the traveling frame 12 is provided with left and right motors 21L and 21R for driving the left and right traveling units 11L and 11R, respectively. Each walking unit 11L, 11R comprises a drive wheel 23L, 23R rotatably mounted on the rear end of the walking frame 12, an idler wheel 24L, 24R rotatably mounted on the front end of the walking frame 12, and a trailer Tracks 22L, 22R between drive wheels 23L, 23R and idler wheels 24L, 24R. The left electric motor 21L is coupled with the left driving wheel 23L, so that the left crawler belt 22L can be driven by power transmitted from the left electric motor 21L through the left driving wheel 23L. Also, the right electric motor 21R is combined with the right driving wheel 23R, so that the right crawler belt 22R can be driven by power transmitted from the right electric motor 21R through the right driving wheel 23R.

The snow removal unit 13 includes an auger 27 rotatably arranged in the auger housing 25, a blower 28 rotatably arranged in a blower housing 26 integrally formed with the rear wall of the auger housing 25, and an auger 28 arranged in the blower housing. Injector 29 on the outlet portion of body 26. The auger housing 25 includes a scraper 35 provided on a lower end thereof, and left and right sleds 36L and 36R provided behind the scraper 35 .

As shown in FIG. 1 , the engine 14 is provided to be operated as a power source for driving the snow removal unit 13 through an electromagnetic clutch 31 and a power transmission mechanism 32 . The electromagnetic clutch 31 is coupled to the crankshaft 14 a of the engine 14 . The power transmission mechanism 32 includes a belt drive mechanism for transmitting power from the electromagnetic clutch 31 to the auger drive shaft 33 . The auger drive shaft 33 is connected to drive the auger 27 and the blower 28 . Through this structure, the power of the engine 14 can be continuously transmitted to the auger 27 and the blower 28 of the snow removal unit 13 through the crankshaft 14a, the electromagnetic clutch 31 and the auger transmission shaft 33 . The auger 27 gathers the snow accumulated on the ground toward the center of the snow blower 10 , and the blower 28 receives the collected snow and throws the collected snow through the ejector 29 to a desired location around the machine 10 .

The pivot drive mechanism 16 includes an electro-hydraulic cylinder actuator having a piston that is reciprocatable to extend and retract from the cylinder under the action of a hydraulic force generated within the cylinder by a hydraulic pump. The hydraulic pump is driven by an electric motor 16a (FIG. 2) embedded in the side of the cylinder as a drive source. One of the piston and the cylinder of the electro-hydraulic cylinder actuator (pivot drive mechanism) 16 is connected to the walking frame 12 , and the other of the piston and the cylinder is connected to the main body frame 15 .

The auger housing 25 and the blower housing 26 are movably mounted on the main frame 15 so that they can roll relative to the main frame 15 around the axis of the auger drive shaft 33 via a rolling drive mechanism 38 ( FIG. 2 ). To this end, the auger drive shaft 33 extending in the front-rear or longitudinal direction of the machine 10 is rotatably supported or journalled on the auger housing 25 or the blower housing 26, and the blower housing 26 is rotatably mounted on the front end portion of the main body frame 15 so as to roll relative to the main body frame 15 .

In addition, since the main body frame 15 is pivotally connected to the walking frame 12 as described above, the auger housing 25 can not only move up and down but also roll left and right relative to the walking frame 12 . Roll drive mechanism 38 includes an electro-hydraulic cylinder actuator having a piston that is reciprocable to extend and retract from the cylinder under the action of hydraulic pressure generated within the cylinder by a hydraulic pump. The pump is driven by a motor 38a (FIG. 2) embedded in the side of the cylinder as a drive source. One of the piston and the cylinder of the electro-hydraulic cylinder actuator (pivot drive mechanism) 38 is connected to the main body frame 15, and the other of the piston and the cylinder is connected to the blower housing 26 integrally formed with the auger housing 25 superior.

The snow blower 10 also includes an operating section 40 provided between the left and right operating handles 17L and 17R, a control unit 61 and a battery 62 vertically arranged one below the other in a specified order.

As shown in FIGS. 3 and 4 , the operating section 40 includes a control box 41 mounted to extend between the left and right operating handles 17L and 17R, a walking preparation unit pivotally mounted on the left operating handle 17L near the left handle 18L. A lever (safety lever) 42 and a left turn control lever 43L, and a right turn control lever 43R pivotally mounted on the right operating handle 17R in the vicinity of the right handle 18R. In the illustrated embodiment, the walk ready lever 42 is disposed directly above the left handle 18L, and the left and right turn control levers 43L and 43R are disposed directly below the left and right handles 18L and 18R, respectively.

A walking ready lever (safety lever) 42 is arranged for actuating its associated switch 42a (Fig. 2). The switch 42a will be referred to as a "walking ready switch". Under the force or bias of a return spring (not shown) acting between the walking preparation lever 42 and the left operating handle 17L, the walking preparation lever 42 is normally disposed at the non-operating position shown in FIG. At , the lever 42 moves upward away from the left handle 18L and the walking preparation switch 42a is in the OFF state. When the operator forces the walking preparation lever 42 downward toward the left handle 18L against the bias of the return spring while gripping the left handle 18L, the walking preparation switch 42 a is turned on by the walking preparation lever 42 . When the force or pressure on the walking ready lever 42 is released, the walking ready lever 42 will return to its initial inoperative position shown in FIG. 3 due to the force of a return spring not shown, so the walking ready switch 42a is turned off.

Left and right turn control levers 43L and 43R are arranged to actuate their respective associated rotary switches 43La and 43Ra (FIG. 2). By the force or bias of return springs, not shown, the left and right rotational control levers 43L, 43R are each normally disposed in the inoperative position shown in FIG. Spaced away from the respective handle 18L, 18R and the associated switch 43La, 43Ra is in the open state. When the operator grasps the left turn control lever 43L and the left handle 18L together, the left turn control lever 43L is pulled up toward the left handle 18L against the bias of the return spring, so the left turn switch 43La is controlled by turning left. The lever 43L is turned on. Likewise, when the operator grasps the right turn control lever 43R and the right handle 18R together, the right turn control lever 43R is pulled upwardly toward the right handle 18R against the bias of the return spring, thereby turning on or actuating the right turn switch 43Ra. When the upward pull or pressure on each respective rotation control lever 43L, 43R is released, the rotation control lever 43L, 43R returns to its initial inoperative position of FIG. 3 under the force of the return spring, thereby enabling the associated rotation The switches 43La, 43Ra are turned off.

As shown in FIG. 3, the control box 41 has a main switch 44 and an auger switch (also referred to as a "clutch operation switch" or "clutch operation switch" or " Drive command switch") 45. The main switch 44 is a rotary switch having at least two positions, an on position and an off position, selectable by rotating the knob along a circular arc. When the main switch 44 is turned on or activated, it starts the engine 14 to run. Similar to a conventional vehicle ignition switch, the main switch 44 may have three positions, an off position, an on position, and a start position. The auger switch 45 is a push button switch that can be operated to engage and disengage the electromagnetic clutch 31 by a manual holding action. The auger switch 45 , when activated, sends a signal to the control unit 61 instructing the control unit 61 to enable power transmission from the engine 14 to the snow removal unit 13 . Therefore, the auger switch 45 functions as a drive command switch.

On the upper surface 41B of the control box 41, a mode selection switch 51, a throttle lever (regulator) 52, a direction speed control lever 53, a reset switch 54, and an auger shell posture control are arranged from left to right in FIG. Lever (snow plow unit attitude control) 55 and injector control lever 56. The mode selection switch 51 , the throttle lever 52 and the direction speed control lever 53 are disposed on the left side of the longitudinal centerline CL of the snow blower 10 , and the direction speed control lever 53 is adjacent to the longitudinal centerline CL. On the other hand, the reset switch 54, the auger casing attitude control lever 55 and the injector control lever 56 are arranged on the right side of the longitudinal centerline CL, and the reset switch 54 is adjacent to the longitudinal centerline CL.

The mode selection switch 51 is a manually operable multi-position switch provided for selecting an optional travel control mode (snow removal operation mode) to be set in the control unit 61 . In the illustrated embodiment, the mode selection switch 51 comprises a rotary switch having a knob 51a manually operable to rotate about its own axis in a first An angular movement is performed between the three positions arranged in sequence of the control position P1 , the second control position P2 and the third control position P3 . The mode selection switch 51 has three switch positions corresponding to the first, second and third control positions P1, P2 and P3 of the knob 51a, respectively. In the individual switch positions, the mode selector switch 51 generates different switching signals.

The selectable travel control modes selectable by the mode selection switch 51 may be determined according to the skill of the operator engaged in the snow removal operation and the conditions of the snow to be removed. More specifically, the first control position P1 is a "manual" position where the engine speed, throttle opening and travel speed of the snow blower can be manually set by an operator. The second control position P2 is the "power" position, where the engine speed and throttle opening can be manually set by the operator, but the travel speed is automatically set regardless of the operator's desire. In this "power" position, the operator is allowed to vary the throwing distance at his discretion. The third control position P3 is the "automatic" position, where the engine speed, throttle opening and walking speed are automatically set.

When the mode selection switch 51 is switched to assume the first control position P1 (ie "manual" position), the switch 51 sends a switch signal to the control unit 61 instructing the control unit 61 to perform control operations in the first control mode. Likewise, when the mode selection switch 51 is switched to assume the second control position P2 (ie "power" position), the switch 51 sends a switch signal to the control unit 61 instructing the control unit 61 to perform control operations in the second control mode. When the mode selection switch 51 is switched to assume the third control position P3 (ie the "automatic" position), the switch 51 sends a switch signal to the control unit 61 instructing the control unit 61 to perform control operations in the third control mode. The first, second and third control mode operations will be described in detail later.

The throttle control lever 52 is an adjusting member, which can be manually operated by the operator to adjust the engine power by controlling the opening degree of the throttle valve 71 ( FIG. 2 ), which is controlled by the electronic governor 65 (Figure 2) in the control motor 72 (Figure 2) to achieve. The throttle lever 52 can be moved by the operator between a forward-most position (full throttle position) and a rear-most position (full throttle position) along the front-to-back direction (longitudinal direction) of the snow blower as indicated by arrows In and De. convert. The throttle lever 52 is connected to a potentiometer 52a such that the potentiometer 52a produces an output potential or voltage corresponding to the current position of the throttle lever 52 . When the throttle lever 52 is in the frontmost full throttle position, the throttle valve 71 is fully opened, and when the throttle lever 52 is in the rearmost full throttle position, the throttle valve 71 is fully closed. By controlling the opening degree of the throttle valve 71 in this way, the number of revolutions of the engine 14 (or engine speed) can be adjusted.

The direction speed control lever 53 is an operating member for controlling the direction and speed of the motors 21L and 21R, as will be described in more detail with reference to FIG. 5 .

The reset switch 54 is used to restore the initial posture of the auger casing 25 . In the illustrated embodiment, reset switch 54 comprises a manual push button switch with indicator light 57 . When the reset switch 54 is pressed, the auger casing 25 is restored to its preset initial posture.

The auger casing posture control lever 55 is an operating part, which is used to control the posture of the auger casing 25 according to the snow surface conditions. In the illustrated embodiment, the auger housing attitude control lever 55 comprises a joystick whose back and forth movement operates the pivot drive mechanism 16 to pivot the auger housing 25 up and down, and whose lateral movement causes the roll The drive mechanism 38 operates to roll the auger housing 25 left and right. The joystick (auger shell posture control lever) 55 is provided with four electronic switches (not shown), and the four electronic switches are set so that when the joystick 55 is operated to move forward direction Frs, backward direction Rrs, left Turned on or activated when leaning in the direction Les and rightwards in the direction Ris.

The injector operating lever 56 is an operating member for changing the orientation of the injector 29 ( FIG. 1 ). In the depicted embodiment, injector lever 56 also comprises a joystick.

Fig. 5 schematically shows the operation of the direction speed control lever 53 of the snow blower. As shown in this figure, the directional speed lever 53 is manually operable to move back and forth through three consecutive ranges "forward", "neutral" and "reverse". Direction speed lever 53 is normally set in a neutral position within the "neutral" range, and when shifted from this neutral position toward the "advance" range as indicated by arrow Ad, snow blower 10 (FIG. 1) can move in the forward direction. Exercise or walk. Alternatively, snow blower 10 may move or travel in a reverse or reverse direction when direction speed lever 53 is shifted from the neutral position toward the "reverse" range. In addition, the forward travel speed of the snow blower 10 can be adjustably changed between a high speed Hf and a low speed Lf by switching the directional speed control lever 53 back and forth within the "forward" range. Likewise, the reverse travel speed of the snow blower 10 can be adjustably changed between a low speed Lr and a high speed Hr by switching the direction speed control lever 35 back and forth within the "reverse" range.

In the described embodiment, the voltage corresponding to each position of the direction speed control lever 53 is generated by the potentiometer 53a (FIG. 2) in such a way that 0 V corresponds to the maximum reverse travel speed and 5 V corresponds to the maximum forward travel speed. , while 2.3V to 2.7V corresponds to the neutral range. In this way, the single direction speed control lever 53 can adjustably set the traveling direction and speed of the snow blower 10 .

Referring to Fig. 2, the control system of the snow blower will be explained. The control system is enhanced by the control unit 61 . The control unit 61 has a storage device or memory 63 incorporated therein for storing various information. The control unit 61 operates to perform various controls based on desired information items read out or retrieved from the memory 63, which will be described below.

First, the operation of the snow removal unit 13 will be explained. The engine 14 has: an intake system including a throttle valve 71 whose opening and closing operation is controlled by a control motor 72 of the electronic governor 65; and a choke valve 73 which is controlled by a control motor 74 of the electronic governor 65 Open and close operations. The electronic governor 65 and the control unit 61 are connected so that the electronic governor 65 can operate the respective control motors 72, 74 based on signals supplied from the control unit 61 to automatically control the opening degree of the throttle valve 71 and the opening of the choke valve 73. Spend. The opening of the throttle valve 71 is detected by a throttle position sensor 75 , and the opening of the choke valve 73 is detected by a choke position sensor 76 . Detection signals indicating the opening degrees of the throttle valve 71 and the choke valve 73 are transmitted from the corresponding position sensors 75 , 76 to the control unit 61 .

The rotational speed (number of revolutions) of the engine 14 is detected by an engine speed sensor 77 . A detection signal from the engine speed sensor 77 is supplied to the control unit 61 .

As the engine 14 turns, the output of the engine 14 is used to drive or turn the generator 81 . Electric power generated by the generator 81 is supplied to the battery 62 , the left and right motors 21L and 21R, and other electrical equipment of the snow blower 10 . The remainder of the output from the engine 14 is supplied to the auger 27 and the blower 28 through the electromagnetic clutch 31 to rotate them.

When the operator activates the auger switch 45 while grasping the walking preparation lever (safety lever) 42 , the electromagnetic clutch 31 is engaged, and the auger 27 and the blower 28 are driven to rotate by the power of the engine 14 . When the operator releases the grip on the walk ready lever (safety lever) 42 thereby allowing the lever 42 to return to its original or free position, or optionally depresses the auger switch 45 again, the electromagnetic clutch 31 returns to disengaged state.

Next, operations of the traveling units 11L and 11R will be explained. Snow blower 10 includes left and right electromagnetic brakes 82L and 82R that function similarly to the parking brakes of a conventional motor vehicle. More specifically, the respective rotation shafts of the left and right electric motors 21L and 21R are kept braked by electromagnetic brakes 82L and 82R. During the stop of the snow blower 10 , the electromagnetic brakes 82L and 82R are in a braking state under the control of the control unit 61 . The electromagnetic brakes 82L and 82R can be brought into a non-braking or releasing state as follows.

Once the direction speed control lever 53 is shifted to the forward or reverse travel position while the main switch 44 is on and the travel preparation lever (safety lever) 42 is gripped by the operator, the electromagnetic brakes 82L, 82R are released. The control unit 61 drives the left and right motors 21L and 21R to rotate through the left and right motor drivers 84L and 84R based on the information on the position of the direction speed control lever 53 received from the potentiometer 53a, and based on the detection of the motor speed sensors 83L and 83R The signal performs feedback control so that the rotational speeds of the respective electric motors 21L and 21R take predetermined values. As a result, the left and right drive wheels 23L, 23R can turn in a desired direction and at a desired speed.

Braking during travel of the snow blower 10 will be achieved in the following manner. Each of the motor drivers 84L and 84R includes a regenerative braking circuit 85L, 85R and a short circuit braking circuit 86L, 86R. The short-circuit braking circuits 86L, 86R constitute braking means.

When the operator grasps the left turn control lever 43L and the left handle 18L together so as to keep the associated rotary switch 43La in the ON state, the control unit 61 activates the left regenerative braking circuit 85L based on the ON signal from the rotary switch 43La to The rotation speed of the left electric motor 21L is reduced. Also, when the operator grasps the right turning lever 43R and the right handle 18R together so as to keep the associated turning switch 43Ra in the ON state, the control unit 61 starts the right regenerative braking based on the ON signal from the turning switch 43Ra Circuit 85R to reduce the speed of the right motor 21R. Therefore, the snow blower 10 turns to the left only when the operator grasps the left turning control lever 43L and the left handle 18L together, and turns to the left only when the operator grasps the right turning control lever 43R and the right handle 18R together. Turn right.

The snow blower 10 can then be stopped from traveling by releasing the travel ready lever (safety lever) 42 and switching the main switch 44 back to the off state or switching the directional speed control lever 53 back to the neutral position.

When the auger housing posture control lever or joystick 55 is pivotally moved back and forth, the motor 16a of the pivot drive mechanism 16 rotates forward and reverse, thereby reciprocating the piston to extend and retract the pivot drive mechanism 16 The cylinder block of the electrohydraulic cylinder actuator. As a result, the auger housing 25 and the blower housing 26 pivotally move up and down. The vertical position of the auger housing 25 is detected by the auger height sensor 87 , and a detection signal from the auger height sensor 87 is supplied to the control unit 61 .

When the auger housing posture control lever or joystick 55 pivots left and right, the motor 38a of the rolling drive mechanism 38 rotates forward and reverse, thereby causing the piston to reciprocate to extend and retract the rolling drive mechanism 38. The cylinder block of the solenoid cylinder actuator. As a result, the auger housing 25 and the blower housing 26 are rolled left and right about the longitudinal centerline CL ( FIG. 4 ) of the snow blower 10 . The roll position of the auger 25 is detected by a roll position sensor 88 , and a detection signal from the roll position sensor 88 is supplied to the control unit 61 .

Referring now to FIGS. 6 to 12 , in order to achieve snow removal operation using the snow removal unit 13 while the snow remover 10 is traveling in the forward direction with the direction speed control lever 53 in the "forward" range and the auger switch 45 in the on state, it will be described. An embodiment of the control performed by the control unit 61 under the condition. The control unit 61 comprises a microcomputer and the control sequence implemented by the microcomputer is started when the main switch 44 is switched from the off position to the on position and is terminated when the main switch is switched back to the off position.

FIG. 6 is a flowchart showing a main routine executed by the control unit 61 to control the engine 14 and the motors 21L and 21R of the snow blower 10 .

Step ST01 of FIG. 6 reads a switch signal from the mode selection switch 51 . Then, step ST02 determines the current position P of the mode selection switch 51 . If the current position P is the first control position P1, control proceeds to step ST03. If the current position P is the second control position P2, control proceeds to step ST04. Alternatively, if the current position P is the third control position P3, control proceeds to step ST05.

Step ST03 executes the first control mode for controlling the engine 14 and the electric motors 21L and 21R. After execution, control returns to step ST01. The manner in which the first control mode is executed will be described later with reference to FIGS. 7 and 8 .

Step ST04 executes the second control mode for controlling the engine 14 and the electric motors 21L and 21R. After execution, control returns to step ST01. The manner in which the second control mode is executed will be described later with reference to FIGS. 9 and 10 .

Step ST05 executes a third control mode for controlling the engine 14 and the electric motors 21L and 21R. After execution, control returns to step ST01. The manner in which the third control mode is executed will be described later with reference to FIGS. 11 and 12 .

FIG. 7 is a flowchart representing a subroutine executed by the control unit 61 to execute the first control mode (step ST03 of FIG. 6 ) for controlling the operations of the engine 14 and the electric motors 21L and 21R.

Step ST101 of FIG. 7 reads the actuation amount (Sop) of the throttle lever 52 represented by the voltage value output by the potentiometer 52 according to the current position of the throttle lever 52 . Then, step ST102 determines the target engine speed (Es) based on the throttle lever actuation amount (Sop).

Subsequently, step ST103 reads the actuation amount (Rop) of the direction speed control lever 53 represented by the voltage value output by the potentiometer 53 a according to the current position of the direction speed control lever 53 . Then, step ST104 determines the target traveling speed (Ms) of the motors 21L and 21R for traveling the snow blower 10 based on the direction speed lever actuation amount (Rop).

Subsequently, step ST105 selectively reads out or retrieves data on the first reference acceleration and the first reference deceleration stored in the memory 63 . The first reference acceleration is a constant used as a reference for performing acceleration control of the motors 21L and 21R. Also, the first reference deceleration is a constant for performing deceleration control of the motors 21L and 21R.

Subsequently, step ST106 selectively reads out or retrieves data on the first reference PID from the memory 63 . The first reference PID is a PID constant used as a reference for performing the PID control of the rotational speeds of the electric motors 21L and 21R.

Then, step ST107 detects the actual rotation number Ne of the engine 14 (ie, the actual engine rotation speed) by reading the output signal of the engine speed sensor 77 .

Subsequently, step ST108 selectively reads or retrieves the first load control map from the memory 63 . As shown in FIG. 8, the first load control map represents a correspondence relationship established between actual engine speed Ne (rpm) on the Y axis and deceleration Rd (%) of traveling units 11L and 11R on the X axis. The term "deceleration Rd" refers to the rate of decrease in the rotational speeds of the motors 21L and 21R (ie, the rate of decrease in the travel speeds of the travel units 11L and 11R), and is also referred to as a "deceleration correction coefficient". If Mnr represents the actual rotational speed of the electric motors 21L and 21R, the actual rotational speed Mbr decreases at the deceleration rate Rd. More specifically, the rotational speeds Mdr of the electric motors 21L and 21R after deceleration can be obtained by the following expression.

Mdr=Mnr×(100-Rd)/100

The performance characteristic of the first load control map is represented by a linear or straight line drawn for establishing the correlation between the actual engine speed Ne and the deceleration Rd so that when Ne is equal to the target engine speed Es, Rd is 0%, and When Ne drops to 0rmp, Rd is Rd1%. Rd1 is set to have a relatively small value. With the first load control map thus prepared, the deceleration of the rotation speeds of the electric motors 21L and 21R (ie, the deceleration of the travel speeds of the traveling units 11L and 11R) slightly increases as the actual engine rotation speed Ne decreases.

In particular, when the snow blower 10 travels with the motors 21L and 21R operating at the actual rotation speed Mnr, the deceleration Rd=0% does not cause any deceleration in the rotation speeds of the motors 21L and 21R, so that the rotation speed Mdr after deceleration is equal to Mnr. Alternatively, if Rd=Rd1%, then Mdr=Mnr×(100−Rd)/100. Also, if Rd=100%, Mdr=0, which means that the rotation speeds of the motors 21L and 21R are reduced to 0, and the snow blower 10 stops traveling.

Referring back to FIG. 7 , step ST108 is followed by step ST109 in which the rotational speed of the engine 14 is controlled based on the target engine rotational speed Es. In the next step ST110, the rotational speeds of the motors 21L and 21R are controlled based on the target walking speed Ms, the first reference acceleration or deceleration, the first reference PID and the first load control map (FIG. 8). Motor rotational speed control is performed in such a manner that when the actual engine rotational speed Ne is shown to decrease relative to the target engine rotational speed Es, the rotational speeds of the electric motors 21L and 21R (i.e., the traveling speeds of the traveling units 11L and 11R) according to the speed shown in FIG. The first load control chart slows down. After the motor rotational speed control performed at step ST110, control returns to step ST03 shown in FIG. 6 .

FIG. 9 is a flowchart showing a subroutine executed by the control unit 61 to execute the second control mode (step ST04 in FIG. 6 ) for controlling the operations of the engine 14 and the electric motors 21L and 21R.

Step ST201 of FIG. 9 reads the actuation amount (Rop) of the direction speed control lever 53, and in the next step ST202, the target walking speed Ms of the motors 21L and 21R is determined from the direction speed control lever actuation amount (Rop).

Then, step ST203 selectively reads out or retrieves data on the second reference acceleration and the second reference deceleration stored in the memory 63 . The second reference acceleration is a constant used as a reference for performing acceleration control of the motors 21L and 21R. Also, the second reference deceleration is a constant for performing deceleration control of the motors 21L and 21R.

Subsequently, step ST204 selectively reads out or retrieves data on the second reference PID from the memory 63 . The second reference PID is a PID constant used as a reference for performing PID control of the rotational speeds of the electric motors 21L and 21R.

Then, step ST205 detects the opening Sa of the throttle valve 71 by reading the output signal of the throttle valve position sensor 75 .

Subsequently, step ST206 selectively reads or retrieves the second load control map from the memory 63 . As shown in FIG. 10, the second load control map represents the correspondence established between the opening Sa (%) of the throttle valve 71 on the Y axis and the deceleration Rd (%) of the traveling units 11L and 11R on the X axis. . The throttle valve opening Sa has a first range defined between a fully closed position (Sa=0%) of the throttle valve 71 and a partially opened intermediate position (Sa=Sa2%), and a second range. The open intermediate position is between the fully closed position and the fully open position (Sa=100%) of the throttle valve 71 , and the second range is defined between the intermediate position and the fully open position of the throttle valve 71 . The intermediate position is located near the fully open position. The second load control chart has performance characteristics represented by lines that curve upward at their mid-positions. The performance characteristic line of the second load control map is determined such that the rate of decline (i.e. deceleration) Rd of the rotational speed of the motors 21L and 21R (i.e. the deceleration Rd of the traveling speed of the traveling units 11L and 11R) is set at the first The throttle opening range is smaller than that in the second throttle opening range, and the drop rate increases as the throttle opening Sa increases.

More specifically, the deceleration Rd of the rotational speeds of the electric motors 21L and 21R (that is, the deceleration of the traveling speeds of the traveling units 11L and 11R) is set so that Rd is 0 when the throttle opening Sa increases from 0% to Sa1%. %, Rd is Rd2% when Sa is Sa2%, and Rd is Rd3% when Sa is 100%, wherein Sa1 is less than Sa2, Rd2 is less than Rd3 and Rd3 is less than 100%.

In this portion of the first throttle opening range extending between Sa1% and Sa2%, the gradient of the performance characteristic line of the second load control map (shown as the first line segment Q1) is greater than that between Sa2% and 100% The gradient (shown by the second line segment Q2 ) in the second throttle opening range extending therebetween is steeper or larger.

As described above, in the first throttle opening range defined between the fully closed position (Sa=0%) and the partially opened intermediate position (Sa=Sa2%) of the throttle valve 71, the rotational speeds of the electric motors 21L and 21R are The deceleration Rd of the travel unit 11L and 11R (that is, the deceleration of the traveling speed of the traveling units 11L and 11R) is set to increase at the first rate as the throttle valve opening Sa increases. The deceleration Rd of the rotational speeds of the electric motors 21L and 21R is within the second throttle opening degree range defined between the partially open intermediate position (Sa=Sa2%) and the fully open position (Sa=100%) of the throttle valve 71 It is set to increase with increasing throttle opening Sa at a second rate greater than the first rate achieved in the first throttle opening range.

When the actual rotational speed Ne of the engine 14 falls due to an increase in the load on the snow removal unit 13, the opening Sa of the throttle valve 71 increases. In this case, according to the second load control map, the rotation speeds of the electric motors 21L and 21R (ie, the traveling speeds of the traveling units 11L and 11R) are appropriately decreased compared to the increase of the throttle opening Sa.

Referring back to FIG. 9 , step ST206 is followed by step ST207 in which the rotational speed of the engine 14 is controlled based on the target engine rotational speed Es. In the next step ST208, the rotational speeds of the motors 21L and 21R are controlled based on the target walking speed Ms, the second reference acceleration or deceleration, the second reference PID, and the second load control map (FIG. 10). Motor rotational speed control is performed in such a manner that when the actual engine rotational speed Ne decreases as the load increases, the rotational speeds of the electric motors 21L and 21R, that is, the walking speeds of the traveling units 11L and 11R are controlled according to the first load shown in FIG. Figure slows down. After the rotation speed control of the electric motors 21L and 21R at step ST208, the control returns to step ST04 shown in FIG. 6 .

FIG. 11 is a flowchart representing a subroutine executed by control unit 61 to execute the third control mode (step ST05 in FIG. 6 ) for controlling the operations of engine 14 and electric motors 21L and 21R.

Step ST301 of FIG. 11 reads or retrieves the target rotational speed Es of the engine 14 from the memory 63 . Then, step ST302 reads the actuation amount (Rop) of the direction speed control lever 53, and in the next step ST303, the target walking speed Ms of the motors 21L and 21R is determined from the direction speed control lever actuation amount (Rop).

Then, step ST304 selectively reads out or retrieves the data on the third reference acceleration and the third reference deceleration stored in the memory 63 . The third reference acceleration is a constant used as a reference for performing acceleration control of the motors 21L and 21R. Also, the third reference deceleration is a constant for performing deceleration control of the motors 21L and 21R.

Subsequently, step ST305 selectively reads or retrieves data on the third reference PID from the memory 63 . The third reference PID is a PID constant used as a reference for performing the rotational speed PID control of the electric motors 21L and 21R.

Then, step ST306 detects the opening Sa of the throttle valve 71 by reading the output signal of the throttle valve position sensor 75 .

In the next step S307, predetermined speed limits are set with respect to the rotational speeds of the electric motors 21L and 21R. In the third control mode, the rotation speeds of the motors 21L and 21R are limited so as to reduce the traveling speeds of the traveling units 11L and 11R to about half. This setting ensures that the snow blower 10 can travel with higher stability, thereby achieving a snow removal operation with higher accuracy than the first and second control modes, which will be described later.

Subsequently, step ST308 selectively reads or retrieves the third load control map from the memory 63 . As shown in FIG. 12, the third load control map represents the correspondence established between the opening Sa (%) of the throttle valve 71 on the Y axis and the deceleration Rd (%) of the traveling units 11L and 11R on the X axis. . The throttle valve opening Sa has a first range defined between a fully closed position (Sa=0%) of the throttle valve 71 and a partially opened intermediate position (Sa=Sa4%), and a second range. The open intermediate position is between the fully closed position and the fully open position (Sa=100) of the throttle valve 71 , and the second range is defined between the partially open intermediate position and the fully open position of the throttle valve 71 . The third load control chart has performance characteristics represented by lines that curve upward at their intermediate positions. The performance characteristic line of the 3rd load control map is determined as the deceleration Rd of the rotating speed of motor 21L and 21R (that is, the deceleration Rd of the walking speed of traveling unit 11L and 11R) is set to be in the first throttle opening range than in The second throttle opening range is large, and the deceleration increases as the throttle opening Sa increases.

More specifically, the deceleration Rd of the rotational speeds of the electric motors 21L and 21R (that is, the deceleration of the traveling speeds of the traveling units 11L and 11R) is set so that Rd is 0 when the throttle opening Sa increases from 0% to Sa3%. %, Rd is Rd4% when Sa is Sa4%, and Rd is 100% when Sa is 100%, wherein Sa3 is less than Sa4, and Rd4 is less than 100%.

In the portion of the first throttle opening range extending between Sa3% and Sa4%, the gradient of the performance characteristic line of the third load control map (as indicated by the first line segment Q3) ratio is between Sa4% and 100% The gradient in the extended second throttle opening range (as indicated by the second line segment Q4 ) is more gradual or smaller.

As described above, in the first throttle opening range defined between the fully closed position (Sa=0%) and the partially open intermediate position (Sa=Sa4%) of the throttle valve 71, the rotational speeds of the electric motors 21L and 21R are The deceleration Rd of the travel unit 11L and 11R (that is, the deceleration of the traveling speed of the traveling units 11L and 11R) is set to increase at the first rate as the throttle valve opening Sa increases. The deceleration Rd of the rotational speeds of the electric motors 21L and 21R is within the second throttle opening degree range defined between the partially open intermediate position (Sa=Sa4%) and the fully open position (Sa=100%) of the throttle valve 71 (i.e., the deceleration of the traveling speeds of the traveling units 11L and 11R) is set to increase with an increase in the throttle opening Sa at a second rate that is smaller than the first achieved in the first throttle opening range. a rate.

When the actual rotational speed Ne of the engine 14 decreases due to an increase in load, the opening Sa of the throttle valve 71 increases. In this case, according to the third load control map, when the throttle opening Sa increases, the rotation speeds of the motors 21L and 21R (ie, the traveling speeds of the traveling units 11L and 11R) rapidly decrease.

Referring back to FIG. 11 , step ST308 is followed by step ST309 in which the rotational speed of the engine 14 is controlled based on the target engine rotational speed Es. In the next step ST310, the rotational speeds of the motors 21L and 21R are controlled based on the target walking speed Ms, the third reference acceleration or deceleration, the third reference PID and the third load control map (FIG. 12). Motor rotational speed control is performed in such a manner that when the actual engine rotational speed Ne decreases due to an increase in load, the rotational speeds of the electric motors 21L and 21R, that is, the traveling speeds of the traveling units 11L and 11R decrease according to the third load control map shown in FIG. slow or lower. After the rotational speed control of the motors 21L and 21R in step ST310, the control returns to step ST05 shown in FIG. 6 .

The constants assigned to the respective reference accelerations and decelerations designated in steps ST105, ST205, and ST304 are set as follows. By using the second reference acceleration and the second reference deceleration as a standard, the first reference acceleration and the first reference deceleration are respectively set to be greater than the second reference acceleration and the second reference deceleration, and the third reference acceleration and the second reference deceleration are set to The three reference decelerations are respectively set to be smaller than the first reference acceleration and the first reference deceleration. In other words, the constants of the first, second and third reference acceleration and deceleration speeds are set in such a manner that the rotational speeds of the electric motors 21L and 21R take a high speed in the first control mode and a middle speed in the second control mode , and take a low speed in the third control mode.

The first, second, and third PID constants used in steps ST106, ST206, and ST305, respectively, for performing walking speed PID (proportional plus integral plus derivative) control are set in such a manner that the first and second The response time in the control mode is shortened, so that the response time in the third control mode is lengthened.

The adjustment of the rotational speed Ne of the engine 14 achieved in each control mode is as follows.

In the first control mode, regardless of the ON/OFF state of the auger switch 45 , the rotational speed Ne of the engine 14 can be adjusted by manually operating the throttle lever 52 at the operator's request. According to the invention, the setting can be modified so that the engine speed Ne can be adjusted only when the auger switch 45 is in the ON state.

In the second control mode, if the auger switch 45 is in the off state, the engine speed Ne remains at a preset given low speed value. Alternatively, when the auger switch 45 is in the ON state, the engine speed Ne can be adjusted by manually operating the throttle lever according to the operator's wishes. In this case, the maximum engine speed can be obtained approximately at maximum engine output.

In the third control mode, when the auger switch 45 is in the OFF state, the engine speed Ne is maintained at a predetermined given lower speed value. Alternatively, when the auger switch 45 is in the ON state, the engine speed Ne is maintained at a predetermined given high speed value substantially corresponding to the maximum torque of the engine 14 .

As can be clearly seen from the foregoing description, in view of the mutual relationship established between the snow removal load and the walking speed, only when the auger switch 45 is in the ON state, the walking speeds of the traveling units 11L and 11R are controlled according to the corresponding load control map .

In the above control program, the left and right motors 21L and 21R can be controlled using pulse width modulation (PWM) in such a manner that the motor drivers 84L and 84R generate pulse signals with pulse width modulation according to the control signal supplied from the control unit 61 to control the rotation of the motors 21L and 21R.

As described so far, the snow blower 10 embodying the present invention includes: the motor 14 mounted on the body 19 for driving the snow removal unit 13; the left and right electric motors 21L and 21R mounted on the body 19 for driving the left and right And right walking unit 11L and 11R so that body 19 can be made snow blower 10 walk along the ground thereby; The electric motors 21L and 21R are operatively connected to each other. The control unit 61 controls the output of the engine 14 and the travel speed of the snow blower 10 based on a plurality of load control modes each corresponding to a load on the snow removal unit 13 . The plurality of load control modes include: a first control mode in which control is performed by an operator based on the rotational speed Ne of the engine 14 through manual operation; a second control mode in which control is performed Thereby, the walking speed of the snow blower 10 is appropriately reduced with respect to the increase of the opening Sa of the throttle valve 71 associated with the engine 14; and a third control mode in which control is performed so that the walking speed of the snow blower 10 The speed decreases with an increase in the opening Sa of the throttle valve 71 to a greater extent than is achieved in the second control mode.

The first control mode is a so-called “manual” mode because it performs control of the walking speed by an operator's manual operation based on the rotational speed Ne of the engine 14 . The rotational speed Ne of the engine 14 tends to decrease as the load on the snow removal unit 13 increases. In this case, the operator can know an increase in the load on the snow removal unit 13 by sensing a decrease in the engine rotational speed Ne. When a decrease in the engine speed Ne is sensed, the operator manually operates the throttle lever 52 in a direction to increase the opening Sa of the throttle valve 71 to such an extent that the engine speed Ne is maintained at a desired value. Since the first control mode is set to perform load control based on the engine rotation speed Ne, this control mode can be used for applications in which the operator can know a change in the load on the snow removal unit 13 . The first control mode allows the operator to fully reflect his wishes or wishes when operating or manipulating the snow blower 10 since the control unit 60 hardly intervenes.

In view of the above, the first control mode should preferably be selected when the operator wishes to operate the snow blower at his own discretion. Therefore, the first control mode is particularly suitable for operation by a skilled operator.

The second control mode is a so-called "power" or "semi-automatic" mode because it performs control in such a way that the walking speed decreases moderately with respect to an increase in the opening Sa of the throttle valve 71 . When the load on the snow removal unit 13 increases, the rotational speed Ne of the engine 14 tends to slow down or decrease. In this case, the operator may manipulate the throttle lever 52 in a direction to increase the opening Sa of the throttle valve 71 in order to maintain the engine speed Ne at a desired value. In the second control mode, the control unit 61 intervenes seldom as long as the power of the engine 14 allows the snow removal unit 13 to operate.

In addition, in the second control mode, the increase in the traveling speed with respect to the opening Sa of the throttle valve 71 is moderately reduced. Therefore, it is preferable to select the second control mode when the operator does not wish a significant deceleration of the walking speed even under heavy load conditions of the snow removal unit 13 . The second control mode is especially suitable for operation by semi-skilled operators or those operators wishing to achieve snow removal operations quickly and efficiently. In the second control mode, the operator can switch the throttle lever 71 in a direction to slow down the engine speed Ne, thereby adjusting the snow throwing distance from the injector 26 .

The third control mode is a so-called "automatic" mode because it performs control in such a way that the walking speed increases with an increase in the opening Sa of the throttle valve 71 to a greater extent than that achieved in the second control mode. The degree is reduced. In the third control mode, if the load on the snow removal unit 13 increases, the opening Sa of the throttle valve 71 is automatically increased to such an extent that the engine speed Ne can be maintained at a desired value. In this case, the increase of the walking speed with respect to the opening Sa of the throttle valve 71 is greatly slowed down. Therefore, when the load on the snow removal unit 13 increases, the traveling speed of the snow removal machine 10 is greatly reduced. The third control mode is preferably selected when the operator wishes to suppress an increase in load on the snow removal unit 13 while allowing some slowing down or reduction of the walking speed. When the third control mode is selected, the operator is assured of the easiest operation of the snow plow and great results.

As the control modes to be realized by the control unit 61, the snow blower 10 embodying the invention has three control modes, namely a manual first control mode especially suitable for skilled operators and a semi-automatic second control mode especially suitable for semi-skilled operators mode, and an automatic third control mode especially suitable for unskilled operators. With such multiple different control modes, snow blower 10 is highly user-friendly to all individual operators of different skill levels.

In a preferred form of the invention, the first control mode is set or arranged such that the rate of decrease in walking speed increases as the rotational speed Ne of the engine 14 decreases. The second control mode is set so that the rate of decrease (i.e. deceleration) of the walking speed is set to be smaller than that in the second range of the throttle opening Sa within the first range of the throttle opening Sa, and the rate of decrease increases with the throttle. The opening Sa of the throttle valve 71 increases, wherein the first throttle opening range is defined between the fully closed position of the throttle valve 71 (throttle fully closed position) and the partially opened intermediate position, and the partially opened intermediate position position between the fully closed position and the fully open position (full throttle position) of the throttle valve 71, and the second throttle opening range is defined between the intermediate throttle position and the fully open throttle position of the throttle valve 71 between. The third control mode is set so that the rate of decline (i.e. deceleration) of the walking speed is set to be greater than that in the second throttle opening range in the first throttle opening range, and the rate of decline increases with the opening of the throttle valve 71. The first throttle opening range is defined between the fully closed position of the throttle valve 71 and the partially open intermediate position, and the partially open second intermediate position is located between the fully closed position and the throttle valve. between the fully open position of the throttle valve 71 , and the second throttle opening range is defined between the second intermediate position of the throttle valve 71 and the fully open throttle valve position.

The first control mode is a mode provided to draw the operator's attention to the occurrence of an inappropriate load. For this reason, the first control mode only needs to increase the rate of decrease or deceleration of the walking speed when the rotational speed Ne of the engine 14 decreases. By selecting the first control mode, when the snow removal unit 13 bears an unsuitable load, the engine speed Ne will be reduced, and the walking speed of the snow removal machine 10 will be reduced due to the increase in deceleration. In this case, the operator can know that an inappropriate load has occurred by sensing a decrease in the travel speed of the snow blower. As a result, the operator can freely operate the snow blower as he wishes according to the load change on the snow removal unit 13 .

When the second control mode is selected, the operator can increase the opening Sa of the throttle valve 71 close to the performance limit of the engine 14, so that the snow removal unit 13 is continuously operated under a high load condition without causing the snow removal machine 10 to travel. A significant reduction in speed occurs (ie, while maintaining the travel speed of snow blower 10 at a substantially constant value). As a result, snow removal operations can be performed quickly and efficiently.

In the second control mode, as can be understood from the second load control map shown in FIG. The deceleration of the velocity increases by a small amount, ie from 0% to Rd2%. In other words, within the first throttle opening range defined between the fully closed position (Sa=0%) and the partially opened intermediate position (Sa=Sa2%) of the throttle valve 71, the rate of decrease in walking speed ( That is, the deceleration rate) Rd is set to increase at the first rate as the opening Sa of the throttle valve 71 increases. In the second throttle opening range defined between the partially opened intermediate position (Sa=Sa2%) and the fully opened position (Sa=100%) of the throttle valve 71, the rate of decrease in walking speed (i.e. deceleration) Rd is set to increase with increasing opening Sa of the throttle valve 71 at a second rate greater than the first rate achieved in the first throttle opening range.

In the snow blower 10 , the rotational speeds of the auger 27 and the blower 28 increase with the rotational speed of the engine 14 . Therefore, the ability of the auger 27 to collect snow and the ability of the blower 28 to throw the collected snow over a distance through the injector 29 (which represent the performance of the snow removal unit 13 ) increases when the engine speed increases. In order to increase the engine speed, the throttle opening Sa should be increased. However, since the deceleration Rd of the traveling speed that increases with the increase of the throttle opening Sa is set relatively small, the traveling speed of the snow blower 10 does not slow down much even if the load on the engine 14 increases.

Therefore, in the second control mode, the opening Sa of the throttle valve 71 can be increased close to the performance limit of the engine 14, so that the snow removal unit 13 can be continuously operated under high load conditions, and at the same time, the walking speed of the snow removal machine 10 can be reduced. maintain a substantially constant value. Therefore, the snow blower 10 can quickly and efficiently complete the snow removal operation.

When the third control mode is selected, a slight increase in the throttle opening Sa can greatly reduce the walking speed of the snow blower 10 . By slowing down the travel speed of the snow blower 10 in this way, the load on the snow removal unit 13 can be reduced, thereby reducing the engine load.

In the third control mode, as can be understood from the third load control map shown in FIG. =Sa4%), the deceleration Rd of the walking speed increases from 0% to Rd4%, and Rd4% approaches 100%. In other words, within the first throttle opening range defined between the fully closed position (Sa=0%) and the partially opened intermediate position (Sa=Sa4%) of the throttle valve 71, the rate of decrease in walking speed ( That is, the deceleration rate) Rd is set to increase at the first rate as the opening Sa of the throttle valve 71 increases. In the second throttle opening range defined between the partially open intermediate position (Sa=Sa4%) and the fully open position (Sa=100%) of the throttle valve 71, the rate of decrease in walking speed (i.e. deceleration) Rd is set to increase with increasing opening Sa of the throttle valve 71 at a second rate that is smaller than the first rate achieved in the first throttle opening range. When Sa=100%, Rd=100%, which means that the snow blower 10 stops walking along the ground.

In the snow blower 10 , the amount of snow to be removed, ie the load on the snow removal unit 13 , increases as the travel speed of the snow blower 10 increases. In order to ensure that the snow removal operation is performed in a stable manner, it is preferable to (a) increase the opening Sa of the throttle valve 71 to maintain the desired rotational speed Ne of the engine 14; or (2) reduce the travel speed of the snow remover 10 to reduce the size of the snow removal unit 13 on the load.

The third control mode is particularly useful for this application, because when the load on the snow removal unit 13 increases, the opening Sa of the throttle valve 71 increases, and the snow blower 10 is at the same time compared with the rate of increase of the opening Sa of the throttle valve 71 . walking speed is reduced even more. By slowing down the traveling speed of the snow blower 10 in this way, it is possible to suppress an undue increase in the load on the snow removal unit 13 and stably achieve a snow removal operation with improved finish quality. Furthermore, since the engine 14 is not being unduly loaded, the fuel economy of the snow blower 10 is good.

By thus providing three different control modes selectable according to the individual operator's skill level, snow blower 10 is very easy to use for all operators including unskilled, semi-skilled and skilled operators. The first, second and third control modes can be easily selected by turning the knob 51a of the mode selection switch 51 to a desired position.

Now, a description will be given of the manner of operating the snow blower with reference to FIGS. 13 to 16 . As shown in FIG. 13A , the operator turns the main switch 44 from the off position to the on position with the right hand 49R in the clockwise direction as indicated by the arrow "a1", thereby starting the engine 14 . Then, the operator turns the knob 51a of the mode selection switch 51 in the counterclockwise direction as indicated by the arrow "a2" with the left hand 49L, thereby setting a desired control mode for the snow removal operation. In the illustrated embodiment, the third control mode (automatic position) P3 (Fig. 3) is selected. Subsequently, as shown in FIG. 13C, the operator grasps the walking preparation lever 42 and the left handle 18L together with the left hand 49L, and while maintaining the grasping of the walking preparation lever 42, the operator controls the speed of the direction as indicated by the arrow "a3". The lever 53 is shifted from the neutral position to the forward travel range (advance position). The snow blower 10 now begins to travel in the forward direction.

As shown in FIG. 14A , the operator then releases the direction speed control lever 53 as indicated by arrow "a4" and grasps the right handle 18R with the right hand 49R. The snow blower 10 continues its travel in the forward direction. Subsequently, the operator presses the auger switch 45 as indicated by arrow "a5" in FIG. 14B , thereby driving the auger 27 ( FIG. 1 ) to rotate using the power from the engine 14 transmitted via the electromagnetic clutch 31 . Snow blower 10 is currently in a state ready to begin snow removal operations. In this case, if the mode selection switch 51 has been set at the first control position (manual position) P1, the operator needs to use his right hand 49R to switch the direction speed control lever back and forth as shown by the arrow "a6" in Fig. 14C 53, thereby adjusting the forward travel speed of the snow blower 10. In all the operations shown in FIGS. 14A to 14C , the walking preparation lever 42 is always in a state of being grasped by the operator.

During snow removal operations, the operator can actuate or switch the auger housing attitude control lever 55 back and forth and side to side with his right hand 49R as indicated by arrow "a7" in FIG. The height and roll of the Dragon 27 (Fig. 2). When the auger 27 is about to return to its initial position, the operator presses the reset switch 54 with his right thumb as shown by the arrow "a8" in Fig. The action of the rolling drive mechanism 38 (FIG. 2) returns to its original position. In addition, the operator can actuate or switch the sprayer operating lever 56 back and forth and side to side with his right hand as indicated by arrow "a9" in FIG. Required desired orientation. During this time, the walking preparation lever 42 is always held by the operator's left hand 49, as shown in FIGS. 15A to 15C.

Since the mode selection switch 51 is set to the third control position (automatic position) P3 as described above with reference to FIG. 13B , the operator does not need to actuate the throttle lever 52 . On the other hand, if the first control position (manual position) P1 has been selected by the mode selection switch 51, the operator needs to actuate the throttle lever 52 with his right hand 49R as indicated by the arrow "a10" in FIG. 16A, In order to adjust the speed of the engine (Fig. 1) according to the conditions of the snow to be cleared. Alternatively, if the second control position (power position) P2 has been selected by the mode selection switch 51, the snow throwing distance from the injector 29 can be adjusted by switching the throttle lever 52 in a suitable manner.

When the operator uses his right hand 49R to switch the speed direction control lever 52 to the reverse travel range (reverse position) through the neutral range, as shown by the arrow "a11" in FIG. walk. Therefore, the operator can interrupt the snow removal operation. If the operator wishes to resume snow removal operations, he or she will use his or her right hand 49R to shift the directional speed control lever 53 from the reverse range through the neutral range to the forward range, as indicated by arrow "a12" in Fig. 16C. During the operations shown in FIGS. 16A to 16C , the walking preparation lever 42 is always gripped by the operator's left hand 49L.

The operator only needs to operate the mode selection switch 51 once before starting the snow removal operation. The go ready lever 42 should remain in the operator's grip during snow removal operations.

As described above, the snow blower 10 according to the present invention includes the mode selection switch 51 provided on the operation portion 40 for the operator to operate the switch to select a snow removal operation mode from a plurality of selectable snow removal operation modes. A variety of selectable snow removal operation modes are preset in the control unit 61 based on the combination of the walking speed of the body, the rotational speed of the engine, and the throttle opening of the engine. A snow blower 10 having such a mode selection switch 51 is user friendly because the operator can select an operating mode that best suits his level of skill in snow removal operations.

The mode selection switch 51 is usually operated once before the start of the snow removal operation, and the walk ready switch is always held by the operator during the snow removal operation. Furthermore, during the snow removal operation, while the operator keeps gripping the walking preparation lever 42 with one hand, the operator frequently actuates the auger housing attitude control lever (snow removal unit attitude control) 55 with the other hand. Therefore, the mode selection switch 51 is preferably located in front of the walking preparation lever 42, so that the mode selection switch 51 and the auger casing posture control lever 55 will not interfere with each other. This increases the efficiency of snow removal operations.

In addition, since the throttle lever (regulator) 52 is located near the mode selection switch 51, this setting allows the operator to adjust the position of the throttle valve 52 to adjust the engine power when the manual position P1 has been selected by the mode selection switch 51, while in the When the power position P2 has been selected by the mode selection switch 51 , the position of the throttle valve 52 is adjusted in order to adjust the snow throwing distance from the injector 29 . With the proximity setting of throttle lever 52 and mode select switch 51, snow blower 10 is able to provide a higher degree of operability.

The mode selection switch 51 preferably comprises a multi-position rotary switch, while the throttle lever 52 is preferably configured to switch back and forth and is disposed between the mode selection switch 51 and the ready-to-go lever 42 . With this arrangement, it is possible to control the manual and power positions P1 and P2 of the mode select switch 51 as well as the engine power and snow throwing distance (which is variable with the position of the throttle lever 52 ) in an interlocking relationship with each other. This will increase the efficiency of snow removal operations.

17 and 18 show an operation section 40' according to a modified example of the present invention. The modified operation section 40' differs from the operation section 40 shown in FIGS. 3 and 4 only in the structures and functions of the main switch 44' and the mode selection switch 51'.

As shown in Figure 17, the master switch 44' is a conventional ignition switch which is activated to start the engine 14 when the operator turns a master key inserted in a keyhole (not shown) in the switch 44'. The main switch 44' has three switch positions, namely an off position, an on position and a starting (starting) position, which are sequentially arranged clockwise around the keyhole in a specified order. Setting the master key to the off position not only shuts off the engine 14 but also shuts down all electrical systems of the snow blower 10 . Switching the master key from the off position to the on position starts all electrical systems in snow blower 10 while leaving engine 14 in an off or stopped state. Setting the master key in the start (start) position starts or starts the engine 14 . Additionally, switching the master key from the start (start) position to the on position changes the started engine 14 directly to its full operation.

When the master key is set to the ON position, the electrical system for supplying power from the battery 62 ( FIG. 2 ) to the motors 21L and 21R is activated so that the snow blower 10 can perform Battery mode walking operation in which the motors 21L and 21R are driven only by electric power supplied from the battery 62 .

The mode selection switch 51' is a manually operable multi-position switch arranged to select an optional travel control mode (snow removal mode of operation) to be set in the control unit 61 (Fig. 2). In the illustrated embodiment, the mode selector switch 51 comprises a rotary switch having a knob 51a' which is manually operable to switch about its own axis between a first control position P1, a second control position P2, a third control position P3 and a second control position P3. Angular movement is performed between four control positions P4, which are successively arranged in a given order around the axis of rotation of the knob 51a'. The mode selection switch 51 has four switch positions corresponding to the first, second, third and fourth control positions P1, P2, P3 and P4 of the knob 51a, respectively. In each switch position, the mode selector switch 51 generates different switching signals.

When the mode selection switch 51' is switched to adopt the first control position P1, it sends a switch signal to the control unit 61, instructing the control unit 61 to perform the control operation in the first control mode. Likewise, when the mode selection switch 51' is switched to adopt the second control position P2, it sends a switch signal to the control unit 61, instructing the control unit 61 to perform control operations in the second control mode. When the mode selection switch 51' is switched to adopt the third control position P3, it sends a switch signal to the control unit 61, instructing the control unit 61 to perform the control operation in the third control mode. When the mode selection switch 51' is switched to adopt the fourth control position P4, it sends a switch signal to the control unit 61, instructing the control unit 61 to perform the control operation in the fourth control mode.

Referring now to FIGS. 19 and 20 , it will be described in order to achieve a snow removal operation with the snow removal unit 13 while the snow remover 10 is traveling in the forward direction when the direction speed control lever 53 is in the "forward" range (see FIG. 5 ) and the auger switch 45 Another example of control performed by the control unit 61 based on an instruction from the modified operation section 51 ( FIG. 17 ) in the condition of being in the ON state.

FIG. 19 is a flowchart representing a main routine executed by the control unit 61 to control the operations of the engine 14 and the motors 21L and 21R of the snow blower 10 .

Step ST1901 of Fig. 19 reads the switch signal from the main switch 44' (Figs. 17 and 18). Then, step ST1902 determines whether the main switch 44' is in the ON position. If the determination in step ST1902 is affirmative (YES), control proceeds to step ST1903. Alternatively, if the determination in ST1902 is negative (NO), control returns to step ST1901.

Step ST1903 reads the switch signal from the mode selection switch 51' (Figs. 17 and 18). Then, step ST1904 determines the current position P of the mode selection switch 51'. If the current position P is the first control position P1, control proceeds to step ST1905. If the current position P is the second control position P2, control proceeds to step ST1906. If the current position P is the third control position P3, control proceeds to step ST1907. Alternatively, if the current position P is the fourth control position P4, control proceeds to step ST1908.

Step ST1905 executes the first control mode for controlling the engine 14 and the electric motors 21L and 21R. After execution of this first control mode, control returns to step ST1903. The first control mode is performed in the same manner as described above with reference to FIGS. 7 and 8 , and further description thereof may be omitted.

Step ST1906 executes the second control mode for controlling the engine 14 and the electric motors 21L and 21R. After executing this second control mode, control returns to step ST1903. The second control is performed in the same manner as described above with reference to FIGS. 9 and 10 , and further description thereof may be omitted.

Step ST1907 executes the third control mode for controlling the engine 14 and the electric motors 21L and 21R. After execution, control returns to step ST1903. The third control mode is performed in the same manner as described above with reference to FIGS. 11 and 12 , and further description thereof may be omitted.

Step ST1908 executes a fourth control mode in which control is performed so that the electric motors 21L and 21R are operated only by electric power supplied from the battery 62 when the engine 14 is in the off state ( FIG. 2 ). After execution of this fourth control mode, control returns to step ST1903. The execution manner of this fourth control mode will be described in more detail below with reference to FIG. 20 .

FIG. 20 is a flowchart representing a subroutine to be executed by the control unit 61 to execute the fourth control mode (step ST1908 of FIG. 19 ).

Step ST401 of FIG. 20 turns off the engine 14 or maintains the off state of the engine 14 . Then, step ST402 reads the signal from each switch, and the signal includes the switch signal from the walking preparation switch 42a (Fig. 2) associated with the walking preparation lever 42 and the switching signal from the mode selection switch 51', and the signal from the indicating direction. The actuation direction of the speed control lever 53 and the output voltage signal of the potentiometer 53a of the actuation amount (Rop) of the speed control lever 53 in the direction. The direction speed control lever actuation direction and actuation amount are determined by the current position of the direction speed control lever 53 and are supplied to the control unit 61 as target walking speed commands for the motors 21L and 21R.

Subsequently, step ST403 determines whether the walking preparation switch 42a is in the ON position (ie, whether the walking preparation lever 42 remains gripped by the operator). If the determination in ST403 is affirmative (YES), control proceeds to step ST404. Alternatively, if the determination in ST403 is negative (NO), control jumps to step ST407.

Step ST404 determines whether the direction speed control lever 53 is in the "forward" walking range or the "reverse" walking range. If the determination is affirmative (YES), control proceeds to step ST405. Alternatively, if the determination is negative (NO), control goes to step ST407.

Step ST405 determines the target walking speed Ms of the motors 21L and 21R based on the actuation amount Pop of the direction speed control lever 53 . Subsequently, step ST406 executes rotation speed control of the electric motors 21L and 21R based on the target walking speed Ms, after which the control proceeds to step ST408.

Step ST407 turns off the motors 21L and 21R, and then control proceeds to step ST408.

Step ST408 determines whether the mode selection switch 51' is in the fourth control position P4. If the determination is affirmative (YES), control returns to step ST402. Alternatively, if the determination is in the negative (NO), control goes to step ST409 where the engine 14 is started or started running. Thereafter, control returns to step 1903 of FIG. 19 .

In the fourth control mode, control is performed so that the electric motors 21L and 21R are operated only by electric power supplied from the battery 62 when the engine 14 is in the non-start state. The snow blower 10 is thus able to travel a shorter distance to thereby perform battery mode travel operation. Because battery-mode travel operation is achieved while engine 14 remains off, fuel costs for engine 14 may be reduced, engine 14 life may be increased, and snowplow 10 operating noise levels may be reduced.

The control unit 61 has a function that only when the main switch 44' has been switched to the on position (ST1902 of FIG. 19) and the operation mode has been switched to the fourth control mode by the operator's manual operation of the mode selection switch 51' (ST904 of FIG. 19 ), the engine 14 is turned off or kept in the off state of the engine 14 (ST401 of FIG. 20 ).

With this arrangement, the operator does not need to perform A separate operation disables the engine 14 from starting. This increases the usability of the snow blower 10 .

In one operation mode, the snow blower 10 performs a snow removal operation with the snow removal unit 13 driven by the engine 14 while the traveling units 11L and 11R are driven to move the snow remover 10 in a desired direction, after which the mode selection switch 51' is activated. Transition to the fourth control position P4, whereby the engine 14 is automatically stopped. Snow blower 10 may continue to travel in the same desired direction until it reaches the desired location.

The control unit 61 also has a function of automatically starting the engine 14 (ST409 of FIG. 20 ) when the operation mode is switched from the fourth control mode to another control mode (ST408 of FIG. 20 ) through the mode selection switch 51'. By automatically starting the engine 14 in this way, the operator does not need to perform a separate operation to start the engine 14 . The snow blower 10 is very easy to use.

Referring now to FIG. 21, a description will be given of a modification of the fourth control mode according to the present invention. FIG. 21 is a flowchart representing a subroutine to be implemented in the control unit 61 to execute the modified fourth control mode. In FIG. 21, steps ST401 to ST408 are the same as those shown in FIG. 20, so that no further description thereof is required. The modified fourth control mode shown in FIG. 21 differs from the fourth control mode in FIG. 20 only in that steps ST501 to ST505 are performed instead of the engine starting step ST409 of FIG. 20 .

If the determination at step ST408 is affirmative (YES), control returns to step ST402. Alternatively, if the determination of step ST408 is negative (NO), control passes to step ST501 where the control unit 61 supplies an alarm signal to the alarm device 58 ( FIG. 22 ) which warns the operator that the engine 14 will is activated. The alarm device 58 may include an indicator light provided on the operation portion 40' as shown in FIG. 22, an alarm sound generator, and the like.

Subsequently, step ST502 reads a switch signal from the main switch 44', and in the next step ST503 it is determined whether the main switch 44' is in an off position, an on position, or a starting (starting) position. If the main switch 44' is in the off position, control proceeds to step ST504. If the main switch 44' is in the ON position, control returns to step ST502. Alternatively, if the main switch 44' is in the start (start) position, control proceeds to step ST505.

Step 504 deactivates the alarm device 58, and thereafter control returns to ST1903 of FIG. 19 .

Step ST505 starts the engine 14 based on a switch signal from the main switch 44' provided at the starting (starting) position. Then, control returns to ST1903 of FIG. 19 . After the engine 14 has achieved steady rotation, the main switch 44' can be switched from the start (start) position to the ON position.

In the modified fourth control mode just described above, the control unit 61 has such a function that only when the operation mode is switched from the fourth control mode to another control mode by the mode selection switch 51' (ST408 of FIG. 21 ) And when the main switch 44' has been switched to the start (start) position (ST503 of FIG. 21 ) to instruct the control unit 61 to start the engine 14, the engine 14 is started (ST505 of FIG. 21 ).

With this arrangement, the operator can A mode change from the fourth control mode to another control mode is definitely known.

FIG. 23 is a flowchart showing a control program executed in the control unit 61 to perform snow removal operations in three different control modes using the snow blower 10 of the structure shown in FIGS. 1 to 5 . In FIG. 23, the control starts operating when the main switch 44 is switched to the on position, and terminates its operation when the main switch 44 is switched to the off position.

Step ST601 reads signals from various switches, including a switch signal from a walk preparation switch 42a (FIG. 2) associated with the walk preparation lever 42, a switch signal from a mode selection switch 51, and a switch signal from an auger switch (drive command switch) 45, and the output voltage signal from the potentiometer 52a associated with the throttle lever 52 and the output voltage signal from the potentiometer 53a associated with the direction speed control lever 53.

Subsequently, step ST602 determines the current position P of the mode selection switch 51 . If the current position P is the first control position ("manual" position) P1, this means that the first control mode ("manual" mode) has been selected. Therefore, control proceeds to step ST603. If the current position P of the mode selection switch 51 is the second control position ("power" or "semi-automatic" position) P2, this means that the second control mode ("power" or "semi-automatic" mode) has been selected. Therefore, control proceeds to step ST604. Alternatively, if the current position P is the third control position ("Auto" position) P3, this means that the third control mode ("Auto" mode) has been selected. Therefore, control proceeds to step ST605.

Step ST603 allows the operator to set the target engine speed Es of the engine 14 by shifting the throttle lever 52 to a desired position. Then, control proceeds to step ST607.

Step ST604 sets the target engine speed Es in the semi-automatic mode. More specifically, if the auger switch (drive command switch) 45 is in a deactivated or off state, the target engine speed Es is set to a given minimum speed set in advance in the control unit 61 . Alternatively, if the auger switch (drive command switch) 45 is in the start or on state, the target engine speed Es is set by switching the throttle lever 52 to the desired position in the same manner as in ST603. Then, control proceeds to step ST607.

Step ST605 determines whether the walking preparation switch 42a is in the OFF state. If the determination is affirmative (Yes), it means that the walking preparation lever 42 is released from the operator's grip, and control proceeds to step ST606. Alternatively, if the determination at ST605 is negative (NO), control proceeds to step ST608.

Step ST606 sets the target engine speed Es of the engine 14 to a given minimum speed Lo which is previously set in the control unit 61 as the target engine speed within the ready-to-work operation range. The minimum rotational speed Lo is determined such that the engine 14 can still produce engine power while running at the minimum speed Lo, which is sufficiently powerful to perform a ready-to-work operation in which engine power is used to control all electrical systems of the snow blower 10 And the battery 62 is charged while the snow removal unit 13 is kept in the closed state.

Step ST607 controls the opening degree of the throttle valve 71 so that the actual rotational speed of the engine 14 is equal to the target engine rotational speed Es set for each selected control mode. To this end, the control motor 72 incorporated in the electronic governor 65 (FIG. 2) is operated to adjust the opening degree of the throttle valve 71 so that the deviation of the actual engine speed from the target engine speed Es becomes zero. Then, control returns to step ST601.

Step ST608 determines the current position of the direction speed control lever 53 . If the direction speed control lever 53 is currently in the neutral position, it is determined that the closing control will be effected. Therefore, control proceeds to step ST606. Alternatively, if the direction speed control lever 53 is currently located at the forward walking position, it is determined that the forward walking control will be implemented. Therefore, control proceeds to step ST609. Alternatively, if the direction speed control lever 53 is currently located in the reverse position, it is determined that reverse travel control will be implemented. Therefore, control proceeds to ST606.

Step ST609 determines whether the auger switch (drive command switch) 45 is in the OFF state. If the determination is affirmative (YES), control proceeds to step ST606. Alternatively, if the determination is negative (NO), control proceeds to step ST610.

Step ST610 sets the target engine speed Es of the engine 14 to a given maximum speed Hi which is preset in the control unit 61 as the target engine speed within the snow removal operation range. The maximum engine speed Hi is determined such that the engine 14 can generate engine power sufficient for the snow removal unit 13 to perform snow removal operation smoothly and reliably when operating at the maximum speed Hi.

As just described above with reference to FIG. 23, the control unit 61 has the function that if the mode selection switch 44 has been set to the "automatic" position (ST602), the direction speed control lever 53 has been shifted from the neutral position toward the forward travel position. (ST608), and the auger switch (drive command switch) 45 is in the ON state (ST609), the rotational speed of the engine 14 is increased to the snow removal operation range (ST610).

By setting the mode selection switch 51 at the automatic position to carry out the automatic control of the rotating speed of the engine 14 and the walking speed of the body 19, when the auger switch (drive command switch) 45 is set at the direction speed control lever 53 of the forward walking position When starting, the engine speed will automatically increase to the snow removal operating range. Accordingly, the snow blower 10 starts to travel forward while the snow removal unit 13 is driven by the engine 14 operating at a higher speed within the snow removal operation range. In this case, however, since the control does not require the operator to perform a separate operation to shift the throttle lever 52 in the direction of increasing the throttle opening, the snow removal operation can be achieved with improved efficiency.

When the walking preparation switch 42a is in the off or off state (i.e. when the operator releases the walking preparation lever (safety lever) 42, the prohibition control unit 61 increases the speed of the transmitter to the above-mentioned function of the snow removal operation range. By prohibiting the control The engine speed increase function of the unit 61 saves fuel costs and extends the life of the engine 14 .

FIG. 24 is a flowchart showing a control program executed in the control unit 61 for performing continuous monitoring of the state of the auger switch (drive command switch) 45 .

Step ST701 determines whether the auger switch 45 is in an off state or in an invalid state. If the determination at ST701 is affirmative (YES), control proceeds to step ST702. Alternatively, if the determination at step ST701 is negative (NO), control proceeds to step ST703.

ST702 disables the electromagnetic clutch 31 so that the clutch is disconnected or disengaged. Thereafter, control returns to ST701.

Step ST703 activates the electromagnetic clutch 31 to thereby place the clutch in an on or engaged state. Then, control returns to ST701.

FIG. 25 is a flowchart showing a control routine executed in the control unit 61 to continuously monitor the state of the walking preparation lever 42 .

Step ST801 determines whether the walking preparation lever 42 is in a disconnected or released state. If the determination in ST801 is affirmative (YES), control proceeds to step ST802. Alternatively, if the determination in step ST801 is negative (NO), control proceeds to step ST803.

Step ST802 turns off the motors 21L and 21R or maintains the off state of the motors 21L and 21R. Then, control returns to ST801.

Step ST803 determines the current position of the direction speed control lever 53 . If the direction speed control lever 53 is currently in the neutral position, this means that the closing control will be performed. Therefore, control continues to step ST802. If the direction speed control lever 53 is currently in the forward travel position, this means that the forward travel control will be performed. Therefore, control proceeds to step ST804. Alternatively, if the direction speed control lever 53 is currently in the reverse position, this means that reverse travel control will be implemented. Therefore, control proceeds to ST805.

Step ST804 drives the motors 21L and 21R to rotate in the forward direction, so that the snow blower travels in the forward direction. Control then returns to ST801.

Step ST805 drives the motors 21L and 21R to move in the reverse or backward direction, so that the snow blower 10 travels in the backward direction. Control then returns to ST801.

The control program shown in FIG. 23 can be modified as shown in FIG. 26 . In the modified control program shown in FIG. 26, if the determination in ST602 indicates that the mode selection switch 51 is set at the second control position ("power" or "semi-automatic" position) P2 to If the control is executed in the "control mode", the control proceeds to ST605 in the same manner as realized in the "automatic" control mode. Therefore, in the "power" or "semi-automatic" control mode, when the auger switch (drive command switch) 45 is activated by setting the direction speed control lever 53 in the forward travel position, the engine speed is automatically increased to the snow removal operation range . If the ready-to-go lever 42 is off or released, no automatic increase in engine speed will occur.

The snow removal unit 13 of the snow remover 10 is by no means limited to the so-called "auger type" comprising a combined auger and blower as in the illustrated embodiment, but may comprise other types of snow removal units as long as the load on the snow removal unit varies with The traveling speed of the snow blower 10 may be increased.

In addition, the power source for driving the traveling units 11L and 11R should not be limited to the electric motors 21L and 21R as in the illustrated embodiment, but may include a hydrostatic motor configured to transmit power from the engine 14 to the traveling units 11L and 11R. Force continuously variable transmission (not shown). Hydrostatic continuously variable transmissions are known per se and have an input shaft for receiving engine power and are capable of moving in forward and reverse directions at continuously variable speeds independently of each other in response to engine power received from the input shaft Rotate and stop left and right output shafts.

The electro-hydraulic cylinder actuators used for the pivot drive mechanism 16 and roll drive mechanism 38 may be replaced by conventional hydraulic cylinder actuators (not shown) that can be driven under the control of a separate hydraulic unit.

Claims (10)

1. A walk-type self-propelled snow removal machine, including: a body (19) having a front end and a rear end; a snow removal unit (13) arranged at the front end of the body for performing snow removal operations; An engine (14) arranged on the body for driving the snow removal unit; a walking unit (11L, 11R) arranged on the body and drivable to make the body walk; left and right operating handles (17L, 17R) extending upwardly and rearwardly from the rear of the body, the operating handles being arranged one on each side of the longitudinal centerline (CL) of the body; a control unit (61) for controlling the operation of said snow removal unit and travel unit; an operating portion (40) mounted to extend between said left and right operating handles for being operated by an operator to provide instructions to said control unit; A snow removal unit posture control part (55) is provided on the operation part on one side of the longitudinal center line of the body, and the snow removal unit posture control part (55) is used to be operated by an operator to control the posture of the snow removal unit ; a walking preparation lever pivotally mounted on one of the left and right operating handles on the other side of the longitudinal centerline of the body, the walking preparation lever for being grasped by an operator to place the body in walking preparation state, the walking ready lever automatically renders the body in a non-walking state when released from the grip by the operator; and a mode selection switch (51) provided on the operating part and located in front of the walking preparation lever, the mode selection switch (51) is used to be operated by the operator to select one snow removal operation mode from a plurality of selectable snow removal operation modes operating modes, the plurality of snow removal operating modes are preset in the control unit based on a combination of the walking speed of the body, the engine speed and the opening of the throttle valve (71) associated with the engine; The multiple selectable snow removal operation modes include: a first control mode, in which an operator performs control through manual operation based on the rotational speed of the engine (14); a second control mode, in which the second control mode mode, execute control so that the walking speed of the body (19) decreases moderately with respect to the increase in throttle (71) opening; and the third control mode, execute control under the third control mode, thereby making The walking speed of the body (19) is reduced relative to the increase in the throttle opening to a greater extent than is achieved in the second control mode. 2. The pedestrian-type self-propelled snow blower according to claim 1, characterized in that it further comprises an adjustment member (52) arranged on the operation part (40) and located near the mode selection switch (51) , the adjusting member (52) is used to be operated by an operator to adjust the power of the engine (14) and the snow throwing distance of the snow removal unit (13). 3. The pedestrian-type self-propelled snow blower according to claim 2, characterized in that, the adjustment member (52) is set at the position of the mode selection switch (51) when viewed along the longitudinal direction of the body (19). and between the walking preparation rod (42). 4. The pedestrian-type self-propelled snow blower according to claim 1, characterized in that the first control mode is set to set the rate of decrease of the walking speed of the body (19) to follow the engine (14 ) speed decreases and increases; the second control mode is set to set the decrease rate of the walking speed of the body so that the rate of decrease in the first throttle opening range is smaller than that in the second throttle opening range Within the range, said drop rate increases with increasing throttle (71) opening, said first throttle opening range is defined between the fully closed position of the throttle and a first partially open first intermediate position, The partially open first intermediate position is located between the fully closed position and the fully open position of the throttle valve, and the second throttle opening range is defined between the first intermediate position and the fully open position of the throttle valve; said The third control mode is set to set the rate of decrease of the walking speed of the body to be larger in the first throttle opening range than in the second throttle opening range, and the rate of decrease increases with the increases with increasing throttle opening, said first throttle opening range being defined between a fully closed position of the throttle valve and a second intermediate position of partial opening at which the throttle valve The second throttle opening range is defined between a second intermediate position of the throttle valve and a fully open position. 5. The pedestrian-type self-propelled snow blower according to claim 1, further comprising a battery (62) for supplying power to the walking unit (11L, 11R), wherein the mode selection switch can The selected plurality of optional snow removal operation modes further includes a fourth control mode in which control is performed so that the travel unit is powered only by power supplied from a battery when the engine (14) is in an off state. operate. 6. The pedestrian-type self-propelled snow blower according to claim 5, further comprising a main switch (44') having a plurality of selectable switch positions manually selectable by the operator, the switch positions including the starting an on position for all electrical systems of the snow plow (10), and an off position for shutting off the electrical systems of the snow plow, wherein the control unit (61) has the function that only when the main switch has been activated The engine (14) is turned off or remains off when the on position is switched to the on position and the operating mode has been switched to the fourth control mode by manual operation of the mode selector switch by the operator. 7. The pedestrian-type self-propelled snow blower according to claim 6, characterized in that, the control unit (61) also has the function of switching from the fourth control mode to another control mode when the operation mode is switched from the fourth control mode to another control mode through the mode selection switch. When automatically starting the function of the engine (14). 8. The walk-type self-propelled snow blower according to claim 6, characterized in that the main switch (44') also has a start position instructing the control unit (61) to start the engine (14), wherein the Said control unit (61) also has the function of starting the engine only when the operation mode has been switched from the fourth control mode to another control mode by said mode selection switch and the main switch has been switched to the start position. 9. The pedestrian-type self-propelled snow blower according to claim 1, characterized in that, the operating part (40) includes: a direction speed control lever (53), which can be manually operated to move forward and backward reciprocating movement between the positions through the neutral position, for adjustably setting the walking direction and walking speed of the body (19); and a drive command switch (45), which can be manually operated to send 61) Provide instructions to enable power transmission from the engine (14) to the snow removal unit (13), wherein said mode selection switch (51) is manually operable to select an automatic position to perform said engine (14) speed and body walk Automatic setting of speed, or select the manual position to allow the operator to manually set the engine speed and body walking speed, wherein the control unit has such a function that if the mode selection switch has been set to automatic position, the directional speed control lever has been shifted from the neutral position toward the forward travel position, and the drive command switch is in the ON state, increasing the engine speed to the snow removal operating range. 10. The walking type self-propelled snow blower according to claim 9, characterized in that if the operator releases the walking preparation lever (42), the control unit (61) increases the speed of the engine (14) to Functions in the operating range are disabled.

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