JP2022107927A - Electric mower - Google Patents

Abstract

To provide an electric mower in which tangling of weeds can be easily and properly eliminated by reverse driving.SOLUTION: The electric mower includes a rotary blade, a motor, a power supply part, a main operation part, a switch operation part, a setting operation part, and a control part. When the switch operation part is operated to a normal rotation state and the main operation part is operated to a driving state, the control part controls the power supply part by making, as a control target, a first control target value that is based on a control reference value set by the setting operation part. When the switch operation part is operated to a reverse rotation state and the main operation part is operated to the driving state, the control part controls the power supply part by making, as a control target, a second control target value that is based on the control reference value set by the setting operation part and reduces a rotation state amount of the rotary blade more than the first control target value.SELECTED DRAWING: Figure 3

Description

The present invention relates to an electric lawn mower.

Electric lawn mowers are widely used as devices for cutting weeds and the like that have grown on the ground. Patent Document 1 discloses an example of a conventional electric lawn mower. In the electric lawn mower disclosed in the document, when the rotary blade is rotated in the normal direction, energization to the motor is controlled based on the control target value adjusted by the adjuster. On the other hand, when rotating the rotary blade in the reverse direction, energization to the motor is controlled based on a predetermined constant reverse control target value regardless of the control target value set by the adjustment unit.

Japanese Patent No. 6085469

One of the main purposes of rotating the rotary blade in the reverse direction when using the electric lawn mower is to eliminate so-called weed entanglement, i.e., weeds entangle the rotary blade or the like. The state of weed entanglement varies depending on the type of weeds growing on the spot, the amount of weeds entangled with the rotary blade, and the like. If the reverse rotation control target value is constant when rotating the rotary blade in the reverse direction, the rotation speed is insufficient and grass entanglement cannot be sufficiently eliminated, or the rotation speed is excessive, causing unintended scattering. It is feared that it will occur. In addition, when the rotary blade is fixed by a screw, there is a possibility that the fixation of the rotary blade may be weakened by an excessive number of revolutions. Furthermore, there is a problem that energy is wasted when the rotary blade is reversed at a high rotation speed that is unnecessary for eliminating grass entanglement.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electric lawn mower that can more easily and appropriately eliminate grass entanglement during reverse driving.

The electric lawn mower provided by the present invention includes a rotary blade that performs a mowing function by rotating in a forward direction, a motor that drives the rotary blade in forward and reverse directions, and power that is supplied to the motor. a power supply unit, a main operation unit for operating the motor to drive and stop, a switching operation unit for switching the rotation direction of the rotary blade, a setting operation unit for setting a control reference value for the rotation state of the rotary blade, and the a control unit that controls the power supply unit based on the operation states of the main operation unit, the switching operation unit, and the setting operation unit; and when the main operation unit is operated to the driving state, the power supply unit is controlled with a first control target value based on the control reference value set by the setting operation unit as a control target, and the switching operation unit When the main operation unit is operated to the reverse rotation state and the main operation unit is operated to the drive state, the rotation state amount of the rotary blade is higher than the first control target value based on the control reference value set by the setting operation unit. The power supply unit is controlled with a second control target value that reduces the .

According to the present invention, grass entanglement can be eliminated more easily and appropriately during reverse drive.

Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

1 is a perspective view showing an example of an electric lawn mower according to the present invention; FIG. 1 is a system configuration diagram showing an example of an electric lawn mower according to the present invention; FIG. 4 is a flow chart showing an example of the operation of the electric lawn mower according to the present invention; 4 is a graph showing one setting example of the control target value of the electric lawn mower according to the present invention. FIG. 5 is a graph showing another setting example of the control target value of the electric lawn mower according to the present invention; FIG.

Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

The terms "first", "second", etc. in this disclosure are merely used to distinguish the terms from each other, and are not intended to impose a permutation of their objects.

1 and 2 show an example of an electric mower according to the present invention. The electric lawn mower A1 of this embodiment includes a rotary blade 1, a motor unit 20, a power supply section 3, a control section 4, a main power supply operation section 50, a main operation section 51, a switching operation section 52, a setting operation section 53, and an energization lamp 60. , a forward/reverse rotation lamp 62 , a speed display lamp 63 , a body case 71 , a shaft 72 , a first handle 73 and a second handle 74 .

The rotary blade 1 is a blade that performs a mowing function by rotating in the forward rotation direction F. As shown in FIG. The rotary blade 1 has a disc shape as a whole, and a plurality of blade portions are arranged on the outer peripheral portion.

The motor unit 20 is a unit containing the motor 2, and is connected to the rotary blade 1 via a drive shaft (not shown). The motor 2 is a drive source that rotationally drives the rotary blade 1, and is, for example, a brushless motor driven by three-phase AC power.

The body case 71 is a member containing the power supply unit 3 and the like, and is, for example, a resin molded product.

The shaft 72 is an elongated support structure member and is made of metal, resin, or the like, for example. The motor unit 20 is fixed to one end of the shaft 72, and the body case 71 is fixed to the other end.

The first handle 73 and the second handle 74 are parts held by the user of the electric lawn mower A1. A first handle 73 and a second handle 74 protrude from the shaft 72 in opposite directions. In this embodiment, the first handle 73 is intended to be gripped by the user's right hand, and the second handle 74 is intended to be gripped by the user's left hand. In this embodiment, a main operation unit 51, a main power supply operation unit 50, a switching operation unit 52, a setting operation unit 53, an energization lamp 60, a forward/reverse rotation lamp 62, and a speed display lamp 63 are attached to the first handle 73. It is Further, in the present embodiment, a battery 31, which will be described later, is attached to the body case 71. As shown in FIG.

The power supply unit 3 is for supplying electric power for driving the motor 2 . The specific configuration of the power supply unit 3 is not limited at all, and in this embodiment, it has a battery 31, a gate driver 32 and a plurality of switching elements 33, as shown in FIG.

The battery 31 stores electric power supplied by the power supply unit 3 . The specific configuration of the battery 31 is not limited at all, and in the present embodiment, it is a lithium ion battery that can be attached to and detached from the main body case 71 . The output voltage of battery 31 is, for example, 13-21 or 26-42V.

The gate driver 32 is a driver that performs switching of the plurality of switching elements 33 and is connected to gate terminals of the plurality of switching elements 33 . The plurality of switching elements 33 are semiconductor elements such as MOSFETs, and constitute a bridge circuit.

The power supply unit 3 converts the DC power of the battery 31 into three-phase AC power through a bridge circuit including a plurality of switching elements 33 under gate control of the gate driver 32 , and outputs the three-phase AC power to the motor 2 . The output voltage of the power supply unit 3 is, for example, 18 to 30 V (effective value).

The control section 4 controls the power supply section 3 based on the operating states of the main operating section 51 , the switching operating section 52 and the setting operating section 53 . In the present embodiment, the control unit 4 transmits a control command to the gate driver 32 of the power supply unit 3 to perform drive control of the motor 2 with a control target value, which will be described later, as a target. The control unit 4 is connected with a main power supply operation unit 50 , a main operation unit 51 , a switching operation unit 52 , a setting operation unit 53 , an energization lamp 60 , a forward/reverse rotation lamp 62 and a speed display lamp 63 .

The main power supply operation unit 50 is an operation unit for switching between power ON, in which the electric lawn mower A1 can operate, and power OFF, in which it cannot operate.

The main operation unit 51 is an operation unit that switches between driving and stopping the motor 2 when the power of the main power supply operation unit 50 is ON. In this embodiment, the main operation unit 51 is attached to the first handle 73 and is operated by being grasped by the user's right hand.

The switching operation portion 52 is an operation portion for switching the rotation direction of the rotary blade 1 between the forward rotation direction F and the reverse rotation direction R. As shown in FIG. The switching operation unit 52 is attached to the first handle 73, for example, and is a push button, a rotary switch, or the like.

The setting operation section 53 is an operation section for setting a control reference value for the rotating state of the rotary blade 1 . The setting operation unit 53 is attached to the first handle 73, for example, and is a push button, a rotary switch, or the like. The setting operation unit 53 is configured to enable an operation to set the control reference value to a desired state, and a configuration that allows selection of a plurality of positions or a configuration that allows the setting value to be continuously varied is appropriately selected. .

The energizing lamp 60 lights up when the main power source operation unit 50 selects power ON, and has a built-in light source such as an LED or a light bulb. The energizing lamp 60 is attached to the first handle 73, for example.

The normal/reverse rotation lamp 62 has a different lighting state corresponding to the selection of the rotation direction of the rotary blade 1 by the switching operation section 52, and has a built-in light source such as an LED or a light bulb. The forward/reverse rotation lamp 62 is attached to the first handle 73, for example.

The speed display lamp 63 lights up corresponding to the number of rotations, which is the rotation state quantity of the rotary blade 1, and has a built-in light source such as an LED or a light bulb. The speed display lamp 63 is attached to the first handle 73, for example.

Next, an operation example of the electric lawn mower A1 will be described below.

When the user selects the main power supply operation unit 50 to turn on the power, the power supply unit 3, the control unit 4, etc. are energized and become operable. As shown in FIG. 3, the control unit 4 acquires the state of the switching operation unit 52 in step S1. When the forward rotation direction F is selected by the switching operation unit 52 (step S1: Yes), the control unit 4 sets the first control target value (step S2). The first control target value is set based on the control reference value set by the setting operation unit 53, and is a quantitative or qualitative rotation state quantity when rotating the rotary blade 1 in the forward rotation direction F. It is a reference value for controlling to

Here, that the first control target value is set based on the control reference value means that the first control target value and the control reference value have a correlation. corresponds to the magnitude (high or low) of the control reference value.

Further, the rotation state quantity of the rotary blade 1 is a state quantity representing the degree of rotation of the rotary blade 1 and is a control target of the motor 2 . The rotation state quantity is mainly the number of revolutions, but is not limited at all. Further, when the control unit 4 duty-controls the power supply to the motor 2 by the power supply unit 3, the duty ratio may be employed as the rotation state quantity. In the following, a case in which the number of rotations N is employed as the rotation state quantity will be described.

FIG. 4 shows the relationship between the control reference value of the setting operation unit 53 and the rotation speed N, which is an example of the rotation state quantity. In this example, the setting operation unit 53 is configured so that three states of "strong", "medium", and "weak" can be selected as the setting reference value. When the control reference value is "strong," the first control target value is set to the highest rotational speed N1s, and when the control reference value is "weak," the first control target value is set to the lowest rotational speed N1w. is set to Further, when the control reference value is "middle", the first control target value is set to the rotation speed N1m between the rotation speed N1s and the rotation speed N1w. Note that the options by the setting operation unit 53 are not limited to the three of "strong", "medium", and "weak", and may be two or four or more. Furthermore, the control reference value set by the setting operation unit 53 may be configured to be selected from stepless values as in an example described later.

Next, when an operation to select driving is performed by the main operation unit 51 (step S4: Yes), the control unit 4 rotates the rotary blade 1 in the forward rotation direction F with the first control target value as the control target. Secondly, the power supply to the motor 2 by the power supply unit 3 is controlled. For this control, for example, by detecting the energization state of the motor 2 or detecting the rotation speed N of the rotary blade 1, feedback control using these information may be performed.

Thus, when the forward rotation direction F is selected by the switching operation unit 52, the rotary blade 1 is set to one of the rotational speeds N1s, N1m and N1w and driven to rotate.

On the other hand, when the reverse rotation direction R is selected by the switching operation unit 52 (step S1: No), the control unit 4 sets the second control target value (step S3). The second control target value is set based on the control reference value set by the setting operation unit 53, and quantitatively or qualitatively determines the rotation state quantity when rotating the rotary blade 1 in the reverse direction R. It is a reference value for control. Also, the second control target value is set to a value that reduces the rotational state quantity of the rotary blade 1 more than the above-described first control target value.

For example, in the example shown in FIG. 4, the second control target values are the rotation speeds N2s, N2m, and N2w corresponding to the control reference values "strong", "medium", and "weak" set by the setting operation unit 53. are set respectively. The rotation speed N2s is the highest, the rotation speed N2w is the lowest, and the rotation speed N2m is a value between the rotation speed N2s and the rotation speed N2w. Further, the rotation speed N2s is lower than the rotation speed N1s, the rotation speed N2m is lower than the rotation speed N1m, and the rotation speed N2w is lower than the rotation speed N1w. The specific relationship between the first control target value and the second control target value is not limited at all. The value may be a value obtained by multiplying the first control reference value by a constant coefficient less than 1 (for example, about 20%).

Next, following step S3, when an operation to select driving is performed by the main operation unit 51 (step S4: Yes), the control unit 4 rotates the rotary blade 1 in the reverse direction with the second control target value as the control target. Power supply to the motor 2 by the power supply unit 3 is controlled so that the motor 2 is driven to rotate in the R direction. For this control, for example, by detecting the energization state of the motor 2 or detecting the rotation speed N of the rotary blade 1, feedback control using these information may be performed.

FIG. 5 shows another example of the relationship between the control reference value, the first control target value, and the second control target value. In this example, the setting operation unit 53 sets the control reference value to a stepless continuous value between 0% and 100%. In step S2, the first control target value is set to a continuous value based on this control reference value. In this example, the first control target value is set to a value having a direct proportional relationship with the control reference value. On the other hand, in step S3, the second control target value is set to a continuous value based on the control reference value. Although the second control reference value has a correlation with the control reference value, it is not in a direct proportional relationship. That is, the second control reference value is such that the coefficient by which the first control target value is multiplied decreases as the control reference value increases. Note that, unlike this example, the second control target value may be a value obtained by multiplying the first control target value by a constant coefficient.

Next, the action of the electric lawn mower A1 will be described.

According to this embodiment, first, when the rotary blade 1 is rotationally driven in the forward rotation direction F, the first control target value is set based on the control reference value of the setting operation unit 53, and the rotation state of the rotary blade 1 The amount (number of rotations N) is set according to the user's intention. As a result, it is possible to mow appropriately according to the state of the weeds to be mowed.

Next, when the rotary blade 1 is rotationally driven in the reverse direction R, the rotary blade 1 is rotationally driven with the second control target value as the control target. The second control target value is a value based on the control reference value, and is set to a value that makes the rotational speed N of the rotary blade 1 lower (reduces the rotation state quantity) than the first control target value. When the rotary blade 1 is rotated in the forward rotation direction F, i.e., when mowing, if the setting operation unit 53 is set to "strong", weeds and the like are tough and dense. It is assumed that this is a state in which the rotational state quantity of the rotary blade 1 is increased. If grass entanglement occurs in such a state, it is presumed that a large amount of weeds are strongly entangled with the rotary blade 1 . When the setting operation unit 53 is set to “strong” and the reverse rotation direction R is selected by the switching operation unit 52 to rotate the rotary blade 1 in the reverse rotation direction R, the rotary blade 1 rotates at a relatively high rotation speed. It is rotated at a certain rotation speed N2s. As a result, it is possible to smoothly eliminate strong grass entanglement.

On the other hand, the number of rotations N1s in the forward rotation direction F is a number of rotations at which tough and dense weeds can be mowed. If such a rotation speed is applied to the rotary blade 1 rotating in the reverse direction R, it is considered that the rotation speed is excessively high to eliminate grass entanglement, resulting in wasted power. However, the rotation speed N2s is a value lower than the rotation speed N1s when rotating in the forward rotation direction F. Therefore, it is possible to avoid rotating the rotary blade 1 in the reverse rotation direction R at a rotational speed that is excessive for eliminating grass entanglement, thereby suppressing power consumption. Therefore, according to the electric lawn mower A1, it is possible to more easily and appropriately eliminate grass entanglement during reverse driving.

Further, when the rotary blade 1 is attached to the motor unit 20 by screwing a screw or the like, the fastening direction of the screw is such that a load is applied to the screw when the rotary blade 1 is rotationally driven in the forward rotation direction F. It is determined in consideration of the rotational force assumed to be applied. Therefore, if an excessive torque is applied to the screw while the rotary blade 1 is rotating in the reverse direction R, the fastening force of the screw is reduced, and the attachment of the rotary blade 1 may become unstable. . According to this embodiment, the second control target value for rotating the rotary blade 1 in the reverse rotation direction R can be set to a value that is reliably smaller than the first control target value for rotating the rotary blade 1 in the forward rotation direction F. be. As a result, it is possible to avoid a situation in which the attachment of the rotary blade 1 becomes unstable.

The electric lawn mower according to the present invention is not limited to the embodiment described above. The specific configuration of each part of the electric lawn mower according to the present invention can be changed in various ways.

A1 : Electric lawn mower 1 : Rotary blade 2 : Motor 3 : Power supply unit 4 : Control unit 20 : Motor unit 31 : Battery 32 : Gate driver 33 : Switching element 50 : Main power supply operation unit 51 : Main operation unit 52 : Switching operation Part 53: Setting operation part 60: Power supply lamp 62: Forward/reverse rotation lamp 63: Speed display lamp 71: Body case 72: Shaft 73: First handle 74: Second handle F: Forward rotation direction R: Reverse rotation direction N, N1m , N1s, N1w, N2m, N2s, N2w: rotation speed

Claims (1)

A rotating blade that performs a mowing function by rotating in the normal direction,
a motor that drives the rotary blade in forward and reverse directions;
a power supply unit that supplies power to the motor;
a main operation unit for operating the motor to drive and stop;
a switching operation unit for switching the rotation direction of the rotary blade;
a setting operation unit for setting a control reference value for the rotating state of the rotary blade;
a control unit that controls the power supply unit based on the operation states of the main operation unit, the switching operation unit, and the setting operation unit;
The control unit
When the switching operation unit is operated to the normal rotation state and the main operation unit is operated to the drive state, the first control target value based on the control reference value set by the setting operation unit is set as the control target, controlling the power supply unit;
When the switching operation unit is operated to the reverse rotation state and the main operation unit is operated to the drive state, the rotation speed is higher than the first control target value based on the control reference value set by the setting operation unit. An electric lawn mower, wherein the power supply section is controlled with a second control target value that reduces the rotation state quantity of the blade as a control target.

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