JP6092005B2 - Mower - Google Patents

Description

  The present invention relates to a mower that can cut a weed on a slope, a pasture, etc.

There is a walking type mower disclosed in Patent Document 1 as a mower that mows grass with a cutting blade that rotates while traveling. This mower is equipped with a front and rear traveling wheels and a steering handle on a mowing portion that pivotally accommodates a cutting blade that is driven to rotate about a vertical axis within a housing, and an engine is disposed above the mowing portion. It is installed.
The mowing unit is provided with a drive shaft that is arranged in a vertical orientation and is rotationally driven by the power of the engine, and a disc-shaped rotary substrate that is fixed to the drive shaft. It is pivotally supported by the outer periphery, and rotates about the vertical axis when the rotary substrate is rotationally driven by the drive shaft. Note that Patent Document 1 discloses using an electric motor instead of an engine.

JP 2007-053993 A

  Grass mowers that use engines or mowers that use electric motors have been developed to provide rotational drive to the cutting blades, but because the engines and electric motors were operated at the rated speed, grass, etc. In some cases, it was not possible to obtain proper rotation of the cutting blade in response to changes in volume. Further, since the rotational speed is constant and rated, it may not be possible to match the walking sensation of the worker in mowing work.

  Therefore, in view of the above problems, the present invention provides a mower capable of adjusting the rotation speed of an electric motor to change the speed of a cutting blade and the speed of a traveling machine body when mowing. Objective.

The technical means taken by the present invention to solve the technical problems are characterized by the following points.
The mower includes an electric motor that transmits power to a rotating shaft that rotates the cutting blade , a traveling machine that travels by power branched from the rotating shaft, and a control device that controls the rotational speed of the electric motor , A steering handle attached to the traveling machine body includes a rotation speed adjustment unit that adjusts a target rotation speed of the electric motor, and the control device has a control map for controlling the electric motor, and the control map is A torque curve indicating the torque of the electric motor, wherein the torque is the actual rotational speed when the actual rotational speed of the electric motor is within a setting range of a target rotational speed set by the rotational speed adjusting unit. When the actual rotational speed falls below the minimum value of the target rotational speed set by the rotational speed adjusting unit, the torque is increased from the value at the minimum value to the actual rotational speed. Characterized in that it has an increased and the torque curve increases at a slower rate than the rate of increase in the said set range as the number of rolling is reduced.

In addition, the control map includes an electric motor corresponding to a lowering operation region that is a region in which the torque is controlled when the actual rotational speed falls below a minimum value of a target rotational speed set by the rotational speed adjusting unit. An electric motor corresponding to a weak magnetic field region that is a region in which the torque is weakened and controlled by magnetic field control when the actual rotational speed is within the target rotational speed range set by the rotational speed adjustment unit. The rotation speed adjustment unit adjusts the target rotation speed within a rotation speed range of the electric motor corresponding to the weakening magnetic field region .

The rotation speed adjustment unit includes an operation member that adjusts the target rotation speed by rotation or movement, and a support unit that supports the operation member so that the operation member can be rotated or moved, and the support unit includes the operation member. The low display portion indicating that the target rotational speed set in step S is the lowest, the high display portion indicating that the target rotational speed set in the operation member is the highest, and the target rotational speed set in the operation member are the low display. A recommended mark indicating that the rotational speed is between the target rotational speed indicated by the section and the target rotational speed indicated by the high display section, so that the speed of the traveling machine body is set to a recommended speed recommended during mowing work. and having a recommendation mark of pointing to the target speed.

The present invention has the following effects.
Conductive by adjusting the rotational speed of the dynamic motor can be appropriately changed the running speed of the rotation and the running body of the cutting blade, for example, or to increase or decrease the rotation of the cutting blade in response to changes in the volume of the grass or the like, mowing In operation, the traveling speed of the traveling machine body can be increased or decreased in accordance with the walking speed of the worker.

In addition, the mowing operation can be performed while rotating the electric motor at a high speed, and the finish of the mowing trace can be made beautiful.
Further, when a load is involved in the mowing work, the mowing work can be performed while maintaining a high torque.
In addition, the mowing operation can be performed at a comfortable speed that matches the walking sensation of the operator when mowing.

It is a whole side view in the walking type mower of the present invention. It is the same whole top view. It is a schematic system diagram in a walking type mower. It is the figure which put together the output characteristic of an engine, and the output characteristic of an electric motor. It is the figure which showed the control map of the electric motor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, the walk-type mower 1 that can cut the sloped grass is roughly divided into a traveling machine body F with front and rear wheels 2 mounted thereon, an electric motor M, and the power of the electric motor M. A rotating cutting blade body 3 is provided. A steering handle H is rotatably attached to the traveling machine body F.

As shown in FIG. 2, the state in which the steering handle H is set in the direction indicated by the two-dot chain line is a standard work state in which an operator can easily accompany, and for convenience of explanation, the traveling direction is set to the front-rear direction (left and right in FIG. 2). Direction), the side where the steering handle H is unevenly distributed is called the left side of the traveling machine body F, and the opposite side is called the right side.
The traveling machine body F connects the left and right side walls 20 with a connecting plate 21 and front and rear handles 22, forms an opening 24 into which the driving case 23 is inserted and arranged in the connecting plate 21, and is omitted in plan view so as to straddle the driving case 23 from the side. A V-shaped pipe frame 25 is fixed to the upper surface of the connecting plate 21. You may form the connection board 21 by multiple sheets in the front-back direction. The pipe frame 25 protrudes from one (left side) side wall 20, and a support base 26 to which the steering handle H is attached is provided on the protruding portion. A steering handle H is supported on the support base 26 so as to be swingable about the vertical axis 11 and the horizontal axis 12.

  The steering handle H is configured by connecting a loop-shaped handle portion H2 to a handle body H1 made of a round pipe material and formed to be foldable in the middle. A work operation lever 7 is rotatably supported on the handle portion H2, and the work operation lever 7 is biased by a spring or the like so as to be separated from the loop handle portion H2. For example, when the operator grips the work operation lever 7 and swings the work operation lever 7 close to the grip portion of the loop handle portion H2 against the spring force, a start switch provided on the control handle H When S is turned on (ON) and the work operation lever 7 is released, the work operation lever 7 is separated from the loop handle portion H2, and the start switch S is turned off (OFF).

As shown in FIG. 2, the drive case 23 is inserted into the opening 24 from above and attached to the left and right side walls 20 and the connecting plate 21, and the electric motor M is attached to the upper part of the drive case 23. The rear side of the electric motor M, the control device 50 is provided, a battery 51 for supplying electric power to the electric motor M and the control unit 50 or the like is provided on the front side. The electric motor M, the control device 50, and the battery 51 are covered with a cover that extends from the front side to the rear side of the traveling machine body F.

Next, the driving system of the walking mower will be described in detail with reference to FIGS.
As shown in FIG. 3, the drive transmission shaft 13 and the cutting blade shaft 4 are rotatably supported by the drive case 23. The output shaft M1 of the electric motor M is connected to the upper part of the drive transmission shaft 13 through a cylinder coupling 27. That is, the output shaft M1 of the electric motor M is connected to the drive transmission shaft 13 without passing through the speed reducer. The lower part of the drive transmission shaft 13 is connected to the cutting blade shaft 4 via a cutting blade clutch C. The lower portion of the cutting blade shaft 4 protrudes downward from the drive transmission shaft 13, and the cutting blade body 3 is detachably attached to the lower portion of the cutting blade shaft 4. That is, the drive transmission shaft 13 and the cutting blade shaft 4 constitute a rotating shaft that transmits rotational power to the cutting blade body 3 (cutting blade 3C), and the power of the electric motor M is transmitted to the rotating shaft (the driving transmission shaft 13 and the cutting blade shaft 3). The cutting blade shaft 4) is directly transmitted to the cutting blade body 3 (cutting blade 3C).

  As shown in FIG. 1, the cutting blade body 3 is provided with a support 3 </ b> A formed in a disc and having a central portion attached to the cutting blade shaft 4, and is erected on the upper surface of the support 3 </ b> A at equal intervals in the circumferential direction. Blade 3B and a cutting blade 3C attached to the outer periphery of the support 3A. Therefore, the cutting blade body 3 (the cutting blade 3C) can be rotated by rotationally driving the drive transmission shaft 13 in a state where the driving transmission shaft 13 and the cutting blade shaft 4 are connected by the cutting blade clutch C.

Now, the traveling machine body F is equipped with a traveling device 30 that causes the traveling machine body F to travel. The traveling device 30 is configured by mounting the front and rear wheels 2 on the front and rear shafts 5 that are penetrated and supported by the front and rear of the left and right side walls 20. The traveling machine F is provided with a transmission mechanism 31 that transmits power from the drive transmission shaft 13 to the front-rear shaft 5.
The transmission mechanism 31 includes a power extraction unit 32 that extracts the power of the drive transmission shaft 13 and a power transmission unit 33 that transmits the power extracted from the power extraction unit 32 to the front and rear shaft 5.

  The power take-out portion 32 includes a worm gear 32A provided between the output shaft M1 of the electric motor M and the cutting blade clutch C, and a worm wheel 32B meshed with the worm gear 32A. The first gear 34A is rotatably provided on the output shaft 34 of the worm wheel 32B, and the second gear 34B meshes with the first gear 34A. In the power take-out portion 32, the power of the drive transmission shaft 13 is transmitted to the bevel pinion shaft 35 provided on the second gear 34B via the worm gear 32A, the worm wheel 32B, the first gear 34A, and the second gear 34B.

  The power transmission unit 33 switches the forward and backward movement of the front and rear wheels 2 and transmits power by chain driving. Specifically, the power transmission unit 33 includes a forward / reverse engagement body 38 that rotates integrally with the bevel pinion shaft 35, and bevel gears 39A and 39B that selectively engage with each other via a shifter. By switching the meshing of the forward / reverse engagement body 38 with respect to the bevel gears 39A, 39B by the shifter, the rotation direction (forward rotation direction, reverse rotation direction) of the transmission shaft 40 that rotates integrally with the bevel gears 39A, 39B is changed to switch between forward / reverse travel. I do.

The power transmission unit 33 is provided with a drive sprocket 37A that rotates integrally with the transmission shaft 40 that rotates integrally, and a driven sprocket 37B that rotates integrally with the front and rear shafts 5, and drives the drive sprocket 37A and the driven sprocket 37B with a chain. It is the composition to do.
As described above, according to the transmission mechanism 31, the worm gear 32A, the worm wheel 32B, the first gear 34A and the second gear 34B, the bevel pinion shaft 35, the forward and backward meshing body 38, the bevel gears 39A and 39B, the transmission shaft 40, the drive sprocket 37A, The rotational driving force of the drive transmission shaft 13 is transmitted through the driven sprocket 37B and the chain.

Next, the electric control system of the walking mower 1 will be described.
As shown in FIG. 3, the walking mower 1 is equipped with a control device 50 and a battery 51 that supplies electric power to the control device 50, an electric motor, and the like.
The electric motor M is a three-phase induction motor. For example, the electric motor M is a multi-pole (10-pole) brushless motor. An inverter 52 is connected to the electric motor M, and a control device 50 is connected to the inverter 52. The inverter 52 sets the rotational speed of the electric motor M by supplying the electric motor M with a three-phase AC voltage formed by switching the DC voltage of the battery 51.

The control device 50 controls driving of the electric motor M and the like, and includes a CPU and the like. The control device 50 is connected to a rotation speed adjustment unit 53 that sets a target rotation speed of the electric motor M. The control device 50 is connected to an inverter 52 (based on the target rotation speed set by the rotation speed adjustment unit 53 and the like. The electric motor M) is controlled.
As shown in FIG. 2, the rotation speed adjustment unit 53 is attached to the steering handle H. Specifically, the rotation speed adjusting unit 53 is attached to a position (near the handle portion H2) that is the handle main body H1 and that can be operated while the operator holds the handle portion H2. The rotation speed adjustment unit 53 is a variable resistor whose resistance value changes depending on the rotation position, and supports an operation member 53a that rotates to adjust (set) the target rotation speed, and supports the rotation of the operation member 53. And a rectangular support portion 53b.

Specifically, the operation member 53a is formed of a cylindrical knob portion that rotates about the vertical axis 54, and the support portion 53b includes a variable resistance element whose resistance value changes depending on the rotation position of the vertical axis 54 inside. It is composed of a rectangular frame body provided.
The knob portion 53a is rotatable within a predetermined range, and an indicator portion 56 indicating a rotation position (operation position) is shown on the upper surface thereof. The support portion 53b supports the knob portion 53a by attaching the central portion of the knob portion 53a to the vertical axis 54. On the upper surface of the support portion 53b, there is provided a rotation display portion 55 indicating the degree (degree) of the target rotational speed indicated by the indicator portion 56 of the knob portion 53a.

  The rotation display section 55 is provided with a band-shaped level display body 55a indicating the target rotational speed of the electric motor M along the outer periphery of the knob section 53a on the upper surface of the support section 53b. A low display portion 55b indicating that the target rotational speed of the electric motor M is the lowest is displayed on one end side of 55a, and a high display portion 55c indicating the highest target rotational speed is displayed on the other end side of the level display body 55a. It is comprised by doing. A recommendation mark 55d is displayed in the middle of the level display body 55a. The recommended mark 55d indicates a position where the number of rotations of the electric motor M is recommended for mowing work (recommended number of rotations). As described later, when the recommended number of rotations is set, the traveling machine body F at the time of mowing is used. Is a comfortable speed that matches the walking sensation of the worker when mowing.

  According to the rotation speed adjustment unit 53, when the index unit 56 (the operation position of the knob unit 53a) of the knob unit 53a is aligned with the low display unit 55b, the electric motor can be selected among the target rotation speeds set by the rotation speed adjustment unit 53. When the target rotational speed of M is set to the lowest rotational speed and the indicator portion 56 of the knob portion 53a is set to the high display portion 55c, the target rotational speed of the electric motor M is set among the target rotational speeds set by the rotational speed adjusting portion 53. When the rotational speed is set to the highest rotational speed and the index portion 56 of the knob portion 53a is set to the recommended mark 55d, the target rotational speed of the electric motor M is recommended among the target rotational speeds set by the rotational speed adjusting section 53. The number of rotations is set. The position of the low display portion 55b, the position of the high display portion 55c, and the position of the recommendation mark 55d are set based on various conditions such as the characteristics of the electric motor M and mowing work.

Next, setting of the target rotational speed of the electric motor M will be described.
In determining the target rotational speed of the electric motor M and its control method, a mower equipped with an engine is referred to, and in particular, the output, rotational speed, torque, and the like of the engine are taken into consideration. FIG. 4 shows the rotation speed, output and torque characteristics of the electric motor M mounted on the mower of the present invention, and the conventional engine rotation speed, output and torque characteristics. As shown in FIG. 4, in a mowing machine equipped with a conventional engine, the mowing operation is performed by increasing the engine speed to the maximum speed of 9000 rpm, and the output and torque are as shown in FIG. . On the other hand, in the lower-time operation region, which will be described later, the output characteristics of the electric motor (the increasing tendency of the torque and the output with respect to the rotational speed) tend to be almost the same as that of the engine. Specifically, in the electric motor M, in the region where the rotational speed is 2200 rpm to 3700 rpm (the operation region during reduction), the curve indicating the output and torque is substantially similar to the curve indicating the engine output and torque.

  In addition, the mower of the present invention equipped with the electric motor M can obtain an output and torque even in a higher rotation range, that is, in a range where the rotational speed exceeds 3700 rpm, compared with the conventional engine. I am doing so. That is, as shown in FIG. 4, in the conventional engine, the maximum rotational speed was 9000 rpm, but in the electric motor M, the rotational speed is increased to 3600 rpm, which corresponds to the engine rotational speed of 9000 rpm, to 4600 rpm. To be able to.

In the mower of the present invention equipped with the electric motor M, the rotational speed exceeding 3700 rpm corresponding to the maximum rotational speed (9000 rpm) of the conventional engine is adjusted (set) by the rotational speed adjusting unit 53.
More specifically, the low display portion 55b (the portion indicating that the lowest rotation speed is set in the rotation speed adjustment section 53) is provided at a position where the target rotation speed of the electric motor M is “3700 rpm”, and the high display section 55c (a portion indicating that the rotation speed adjustment unit 53 sets the highest rotation speed) is provided at a position where the target rotation speed of the electric motor M is “4600 rpm”.

  Accordingly, when the index portion 56 of the knob portion 53a is set to the low display portion 55b, the target rotational speed of the electric motor M is set to 3700 rpm, and a torque similar to the maximum rotational speed (9000 rpm) in the engine type is output. Is possible. In the state where the index portion 56 of the knob portion 53a is aligned with the low display portion 55b and the rotational speed of the electric motor M is 3700 rpm, the mowing machine equipped with the electric motor M has a cutting blade as compared with the engine-type mower. Although a torque similar to that of the engine of 3C (at the time of mowing) can be secured, the traveling (mowing speed) of the traveling machine body F (the traveling device 30) during the mowing operation is slightly slowed.

  Therefore, the recommended speed at which the mowing speed of the traveling machine body F (traveling apparatus 30) is recommended, that is, the rotational speed (target rotational speed) of the electric motor M at which the speed is almost the same as that of the engine-type mower is recommended mark 55d. Shown by. That is, when the target rotational speed of the electric motor M is matched with the rotational speed indicated by the recommendation mark 55d, the speed of the traveling machine body becomes the recommended speed in mowing work. Therefore, it is possible to efficiently mow large-volume grass and the like at a speed that the operator feels just right.

  On the other hand, in the state where the index unit 56 of the rotation speed adjustment unit 53 is set to the high display unit 55c, the rotation speed of the electric motor M can be further increased. Therefore, for example, in mowing work, the area of mowing or mowing For example, when the volume is large, the electric motor M can be rotated at high speed to quickly cut the grass. Further, by setting the rotation speed of the electric motor M to the high display portion 55c side (4600 rpm), the mowing speed at the time of mowing and the moving speed while moving on the road can be increased.

As described above, according to the mower of the present invention equipped with the electric motor M, the target rotational speed of the electric motor M is set by rotating the knob portion 53a from the low display portion 55b to the high display portion 55c. Mowing work can be performed while changing between 3700 rpm and 4600 rpm.
Now, in the situation where the mowing operation is performed, the load applied to the cutting blade 3C fluctuates. As a result, even if the target rotational speed of the electric motor M is adjusted by the knob 53a, the actual rotational speed of the electric motor M is changed. Will change. The actual number of revolutions of the electric motor is called the actual number of revolutions.

Next, the control when the actual rotational speed is lower than the target rotational speed of the electric motor M will be described.
As shown in FIG. 5, the control device 50 includes a control map 60 for controlling the electric motor M. FIG. 5 excludes the characteristics of the engine of FIG. 4, and the torque and output characteristics of the electric motor are the same. In FIG. 5, when the electric motor M is controlled, the controller 50 performs the magnetic field control to increase the rotational speed of the electric motor M to 3700 rpm or higher.

  When the actual rotational speed of the electric motor M is within the range of the target rotational speed set by the rotational speed adjusting unit 53 during the mowing operation, the control device 50 causes the electric motor M to perform the weak magnetic field control. That is, the inverter 52 is controlled. For example, when the actual rotational speed of the electric motor M is within the range of 3600 rpm (low speed side) indicated by the low display portion 55 b to 4600 rpm indicated by the high display portion 55 c, the control device 50 causes the weakening magnetic field of the control map 60. The torque and output of the electric motor M are controlled according to the curve Q1 shown in the region. That is, when the load applied to the cutting blade 3C is small and the actual rotational speed of the electric motor M is within the target rotational speed set by the rotational speed adjusting unit 53, the rotational speed of the electric motor M is reduced to 3700 rpm by the weakening magnetic field vector control. Maintain above.

As described above, since the electric motor M is controlled by the weak magnetic field control when the actual rotational speed of the electric motor is within the range of the target rotational speed set by the rotational speed adjusting unit 53, the high-speed rotation is maintained when the load is small. The mowing work can be done and the finish can be cleaned.
On the other hand, when the mowing operation is being performed, when the actual rotational speed of the electric motor M falls below the minimum value of the target rotational speed set by the rotational speed adjusting unit 53, that is, 3700 rpm ( When the speed is lower than the low speed side), the control device 50 does not perform the magnetic field control and controls the electric motor M with low rotation and high torque. The control device 50 controls the torque and output of the electric motor M in accordance with the curve Q2 indicated in the operating region at the time of lowering instead of the weak magnetic field region of the control map 60. This lowering operation range (2200 to 3699 rpm) is a region where torque can be relatively maintained even at a low rotation. For example, a curve indicating an output (output curve) is up to 3699 rpm as the number of rotations exceeds 2200 rpm. The curve indicating the torque (torque curve) increases gradually from 2200 rpm to 3699 rpm, and the torque decrease with respect to the increase in the rotational speed is small, and the torque is low and high. That is, when the load applied to the cutting blade 3C is large and the actual rotational speed of the electric motor M falls below the minimum value of the target rotational speed set by the rotational speed adjusting unit 53, vector control based on the normal operation range control map 60 is performed. Thus, the rotation speed of the electric motor M is maintained in the range of 2200 to 3699 pm.

As described above, when the actual rotational speed of the electric motor M falls below the minimum value of the target rotational speed set by the rotational speed adjusting unit 53, the electric motor M is controlled with low rotation and high torque, so that the load is large. Sometimes mowing can be done with strong torque by low-speed rotation.
In the above-described embodiment, the operation member 53a is configured by the knob portion that adjusts the target rotational speed by rotating the operation member 53a. However, instead of this, the operation member 53a is laterally (horizontal) with respect to the support portion 53b. You may comprise with the slider which adjusts a target rotational speed by moving to (sliding). Further, the rotational speed, torque, and output characteristics of the electric motor M are not limited to the rotational speeds shown in FIGS.

DESCRIPTION OF SYMBOLS 1 Walking type mower 3C Cutting blade 53 Rotational speed adjustment part H Steering handle F Traveling machine body M Electric motor

Claims (3)

An electric motor that transmits power to a rotating shaft that rotates the cutting blade , a traveling machine that travels by power branched from the rotating shaft, and a control device that controls the rotational speed of the electric motor ,
The steering handle attached to the traveling machine body includes a rotation speed adjustment unit that adjusts a target rotation speed of the electric motor ,
The control device has a control map for controlling the electric motor,
The control map is
A torque curve indicating the torque of the electric motor, wherein the actual rotational speed of the electric motor is within a setting range of a target rotational speed set by the rotational speed adjustment unit; Increases as it decreases,
When the actual rotational speed falls below the minimum value of the target rotational speed set by the rotational speed adjusting unit, the torque increases as the actual rotational speed decreases from the value at the minimum value and the setting A mower having a torque curve that increases at a slower rate than the rate of increase within the range . The control map is
A range of the rotational speed of the electric motor corresponding to the operating region at the time of lowering, which is a region for controlling the torque when the actual rotational speed falls below a minimum value of the target rotational speed set by the rotational speed adjusting unit;
A range of the rotational speed of the electric motor corresponding to the weak magnetic field region, which is a region where the torque is weakened and controlled by magnetic field control when the actual rotational speed is within the range of the target rotational speed set by the rotational speed adjustment unit. Have
2. The mower according to claim 1, wherein the rotation speed adjustment unit adjusts the target rotation speed within a range of a rotation speed of an electric motor corresponding to the weakening magnetic field region . The rotation speed adjustment unit includes an operation member that adjusts the target rotation speed by rotation or movement, and a support unit that supports the operation member so as to rotate or move.
The support portion is set with the low display portion indicating that the target rotational speed set by the operating member is the lowest, the high display portion indicating that the target rotational speed set by the operating member is the highest, and the operating member. A recommended mark indicating that the target rotational speed is a rotational speed between the target rotational speed indicated by the low display portion and the target rotational speed indicated by the high display portion, and the speed of the traveling machine body is reduced during mowing work. mowing machine according to claim 2, characterized in that it comprises a recommendation mark pointing to the target speed to the recommended speed recommended.

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