Control unit and agricultural machinery

Abstract

The present invention provides a control unit capable of protecting the control unit that drives the motor, and an agricultural machine. [Solution] The control unit 1 is applied to a work machine that includes a starter motor 4 connected to an engine 3, a starter circuit C1 that starts the engine 3 by driving the starter motor 4, and a charging circuit C2 that charges a battery 2 with electricity generated by the starter motor 4 using the power of the engine 3. The control unit 1 includes a control unit 54 that controls the driving of the starter motor 4 through the starter circuit C1, and a switching unit 8 that switches from an engine start state S1 in which the starter motor 4 is connected to the starter circuit C1 to a battery charging state S2 in which the starter motor 4 is connected to the charging circuit C2. The control unit 54 controls the switching unit 8 to switch from the engine start state S1 to the battery charging state S2 when predetermined conditions regarding the rotation state of the starter motor 4 are met after the start of driving of the starter motor 4.

Description

[Technical Field]

[0001] The present invention relates to a control unit and an agricultural working machine. [Background Art]

[0002] Patent Document 1 describes a mower including a power mechanism unit. The power mechanism unit includes an engine, a first motor, a first pulley, a second pulley, and a first belt. The engine has a rotating shaft capable of transmitting power to the outside, and the rotating shaft is inserted into the first pulley to transmit rotation of the engine. The first motor has a rotating shaft capable of transmitting power to the outside, and the rotating shaft is inserted into the second pulley to transmit rotation of the first motor. The first belt is looped around the first pulley and the second pulley, and is provided so as to enable power transmission between the first pulley and the second pulley. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2022-120740 [Summary of the Invention] [Problems to be Solved by the Invention]

[0004] In the mower described above, the first motor rotates when electric power is supplied thereto. When starting the engine, a control unit of the power mechanism supplies electric power to drive the first motor, whereby the power of the first motor is transmitted to the second pulley via the rotating shaft, causing the second pulley to rotate. Power is transmitted to the first pulley via the first belt looped around the second pulley. The engine rotates via the rotating shaft inserted into the first pulley, and the engine is started.

[0005] After the engine starts, during normal operation, the engine's power is transmitted to the first pulley via the rotating shaft, causing the first pulley to rotate. Power is then transmitted to the second pulley via the first belt, which is wrapped around the first pulley. The first motor rotates via the rotating shaft inserted into the second pulley, and the first motor continuously generates electricity.

[0006] By the way, in the lawnmower described in Patent Document 1, the first motor is used in common when starting the engine and when generating electricity. When generating electricity, the first motor can generate a large amount of power. Therefore, the large amount of power generated by the first motor may flow to the control unit that supplies power to the first motor. In order to reliably protect the control unit, it is desirable to be able to suppress the flow of large amounts of power to the control unit.

[0007] The present invention aims to provide a control unit capable of protecting the control unit that drives the motor, and an agricultural machine. [Means for solving the problem]

[0008] [1] A control unit (1) according to one aspect of the present invention is applied to a work machine that includes a motor (4) connected to an engine (3), a starting circuit (C1) that starts the engine (3) by driving the motor (4), and a charging circuit (C2) that charges a battery (2) with electricity generated by the motor (4) using the power of the engine (3), and comprises a control unit (54) that controls the driving of the motor (4) through the starting circuit (C1), and a switching unit (8) that switches from a first state (S1) in which the motor (4) is connected to the starting circuit (C1) to a second state (S2) in which the motor (4) is connected to the charging circuit (C2), wherein the control unit (54) controls the switching unit (8) to switch from the first state (S1) to the second state (S2) when predetermined conditions regarding the rotation state of the motor (4) are met after the motor (4) has started to be driven.

[0009] According to the control unit (1) [1], one motor (4) enables both the starting of the engine (3) and the charging of the battery (2). Since the starting circuit (C1) is connected to the control unit, in the first state, the control unit may be affected by the power generated by the motor (4). After the motor (4) starts to drive, if predetermined conditions regarding the rotational state of the motor (4) are met (for example, the rotational speed of the motor (4) reaches a certain level or higher, the engine (3) reaches a certain number of rotations, or a certain amount of time has elapsed since the motor (4) started to drive, etc.), the control unit (1) switches the motor (4) to a second state in which it is connected to the charging circuit (C2). This disconnects the control unit from the motor (4) and protects the control unit. While the engine (3) is in a stable normal operating state, the battery (2) is charged through the motor (4) and the charging circuit (C2).

[0010] [2] The control unit (1) described in [1] further includes a monitoring unit (51) that monitors the rotational speed of the motor (4), and the control unit (54) may control the switching unit (8) to switch from the first state (S1) to the second state (S2) when the rotational speed of the motor (4) monitored by the monitoring unit (51) becomes greater than the rotational speed of the motor (4) corresponding to the rotational speed of the engine (3) when the engine (3) is started. With this configuration, when the rotational speed of the motor (4) becomes large, it is possible to quickly switch to the second state (S2). In other words, it is possible to switch to the second state (S2) before the motor (4) generates a large amount of power. Therefore, the control unit (54) can be protected.

[0011] [3] In the control unit (1) described in [2] above, the monitoring unit (51) monitors the rotation direction of the motor (4), and the control unit (54) may control the switching unit (8) to switch from the first state (S1) to the second state (S2) if the rotation direction of the motor (4) is reversed. With this configuration, the rotation direction of the engine (3) can be monitored by monitoring the rotation direction of the motor (4). If the rotation direction of the motor (4) is reversed, the rotation direction of the engine (3) is also reversed, and there is a possibility that the engine (3) is experiencing a rotational abnormality. The control unit (54) controls the switching unit (8) to switch from the first state (S1) to the second state (S2) if the rotation direction of the motor (4) is reversed, so safety can be ensured by switching to the second state (S2) without continuing to start the engine (3) with the motor (4) in a state where there is an abnormality.

[0012] [4] In any one of the control units (1) described in [1] to [3] above, the switching unit (8) may have a relay circuit (C3) that includes a switch (81) for switching between a first state (S1) and a second state (S2). With this configuration, the relay circuit (C3) switches between the first state (S1) and the second state (S2), so that the first state (S1) and the second state (S2) can be switched using physical contacts. Therefore, the flow of power to the control unit (54) when switched to the second state (S2) can be further suppressed. Thus, the control unit (54) that drives the motor (4) can be protected.

[0013] [5] In the control unit (1) described in [4] above, the switch (81) may be a normally closed switch that maintains the second state (S2) when de-energized. With this configuration, even if power cannot be supplied to the relay circuit (C3), the switch (81) maintains the second state (S2) when de-energized, so the power generated by the motor (4) is less likely to flow to the control unit (54). Therefore, the control unit (54) that drives the motor (4) can be protected.

[0014] [6] An agricultural machine according to one aspect of the present invention comprises an engine (3) whose output power is used for agricultural work, a motor (4) which starts the engine (3) and generates electricity when power is transmitted from the engine (3), a power transmission unit which transmits the power of the engine (3) and the motor (4) to each other, a battery (2) which is charged with electricity generated by the motor (4), a starting circuit (C1) which starts the engine (3) by driving the motor (4), a charging circuit (C2) which charges the battery (2) with electricity generated by the motor (4) using the power of the engine (3), and any one of the control units (1) to (5).

[0015] According to the agricultural machine (100) in [6], by applying the control unit (1) described above, it is possible to start the engine (3) and charge the battery (2) with a single motor (4) while protecting the control unit (54).

[0016] [7] The agricultural implement (100) described in [6] above is further equipped with a recoil starter (7) for starting the engine (3), and the control unit (54) may control the switching unit (8) to switch from the first state (S1) to the second state (S2) when the recoil starter (7) is operated. With this configuration, the engine (3) can be started without driving the motor (4). And, since the control unit (54) controls the switching unit (8) to switch from the first state (S1) to the second state (S2) when the recoil starter (7) is operated, it is possible to switch to the second state (S2) when the engine (3) is started by the recoil starter (7). Therefore, the control unit (54) that drives the motor (4) can be protected. [Effects of the Invention]

[0017] According to the present invention, the control unit that drives the motor can be protected. [Brief explanation of the drawing]

[0018] [Figure 1]Figure 1 is a perspective view of an agricultural working machine to which a control unit according to an embodiment of the present invention is applied. [Figure 2] Figure 2 is a block configuration diagram of the agricultural working machine in an engine started state. [Figure 3] Figure 3 is a block configuration diagram of the agricultural working machine in a charged state. [Figure 4] Figure 4 is a flowchart showing a control method for the agricultural working machine. [Figure 5] Figure 5 is a flowchart showing a motor drive processing method. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same reference numerals are assigned to the same elements, and overlapping descriptions are omitted.

[0020] As shown in Figure 1, the agricultural working machine 100 is, for example, an unmanned and travelable mower. The agricultural working machine 100 includes, for example, a vehicle body 101 having two pairs of drive wheels W. The vehicle body 101 may be capable of autonomous traveling, or may travel by being operated by an operator. The vehicle body 101 freely travels not only on a flat working surface but also on working surfaces of any three-dimensional shape, including surfaces of mountains or hills that include slopes. The agricultural working machine 100 is, for example, a radio-controlled mower. In addition to the vehicle body 101, the agricultural working machine 100 includes a radio-controlled transmitter (not shown) and the like.

[0021] The vehicle body 101 has, for example, a vehicle body frame 102 having a rectangular outer shape. The vehicle body 101 has a drive motor 103 that drives each of the two pairs of drive wheels W. The drive motor 103 is connected to each drive wheel W. That is, in the agricultural working machine 100 of the present embodiment, the power source of each drive wheel W is the corresponding drive motor 103. The vehicle body 101 has two batteries 2 that supply electric power to the four drive motors 103.

[0022] The vehicle body 101 also has a work section (not shown) used for agricultural work. The vehicle body 101 has multiple cutting blades as the work section. The multiple cutting blades are attached to the lower part (underside) of the vehicle frame 102. The cutting blades are rotated in a predetermined direction by the engine 3, which will be described later, to perform the work of cutting grass. The output shaft of the engine 3 is connected to the rotation shaft of the cutting blade directly or indirectly via a reduction gear or the like. The cutting blades rotate continuously while the vehicle body 101 is running. The vehicle frame 102 is equipped with the two batteries 2, the engine 3, a fuel tank for storing gasoline which is the fuel for the engine 3, etc. The axles of the four drive wheels W are also supported by the vehicle frame 102.

[0023] The vehicle body 101 performs turns using a skid steer system. That is, the four drive wheels W are not steerable, and turns are performed by utilizing the speed difference of each drive wheel W. The vehicle body 101 is controlled by a main control unit 5, which will be described later. The main control unit 5 is mounted, for example, on the vehicle frame 102, adjacent to one of the batteries 2. The "main control unit" will be abbreviated as MCU in the following description.

[0024] The vehicle body 101 has an engine 3. As described above, at least a portion of the power output by the engine 3 is used to rotate the workpiece (for agricultural work). The engine 3 is, for example, a two-stroke engine. The engine 3 has known components such as reciprocating members such as a cylinder and piston (not shown), rotating members such as a crankshaft, and a fuel supply mechanism such as a carburetor. The engine 3 may also be a four-stroke engine. The engine 3 has a rotating shaft (not shown) that can transmit power to the outside. The vehicle body 101 is equipped with a recoil starter 7 that can manually start the engine 3. The recoil starter 7 has the same shaft as the engine 3.

[0025] The vehicle body 101 includes a starter motor (motor) 4 that starts the engine 3 and generates electricity, and a power transmission unit 6 that transmits power from the engine 3 and the starter motor 4 to each other. The starter motor 4 is connected to the engine 3 by the power transmission unit 6. The power transmission unit 6 has a first pulley 61 that rotates with the engine 3, a second pulley 62 that rotates with the starter motor 4, and a belt 63 that transmits power from the first pulley 61 and the second pulley 62 to each other. The rotating shaft of the engine 3 is inserted into the first pulley 61. The starter motor 4 has a rotating shaft (not shown) that can transmit power to the outside. The rotating shaft of the starter motor 4 is inserted into the second pulley 62. The outer diameter of the first pulley 61 is larger than the outer diameter of the second pulley 62. An example of the belt 63 is a V-belt.

[0026] The starter motor 4 is driven by power supplied to it. The starter motor 4 is, for example, a brushless motor. The starter motor 4 is driven by power supplied from the battery 2. Three-phase AC power is supplied to the starter motor 4. When power is supplied to the starter motor 4 while the engine 3 is stopped, the starter motor 4 rotates. When the starter motor 4 rotates, power is transmitted to the engine 3 via the second pulley 62, belt 63, and first pulley 61. When power is transmitted to the engine 3 and the engine 3 rotates at a predetermined rotational speed or higher, the engine 3 starts.

[0027] On the other hand, the starter motor 4 can function as a generator when power from the engine 3 is transmitted to it and it is rotated. After the engine 3 starts, as the engine 3 rotates, power is transmitted to the starter motor 4 via the first pulley 61, belt 63, and second pulley 62. When power is transmitted to the starter motor 4 and the starter motor 4 rotates, the starter motor 4 generates electricity. The starter motor 4 functions as a generator and produces three-phase alternating current power. The electricity generated by the starter motor 4 is used to charge the battery 2.

[0028] As shown in Figures 2 and 3, the vehicle body 101 has a switchable circuit. Specifically, the vehicle body 101 has a starting circuit C1 that starts the engine 3 by driving the starter motor 4, and a charging circuit C2 that charges the battery 2 with the power generated by the starter motor 4 using the power of the engine 3. The vehicle body 101 switches between an engine starting state S1 (first state) in which the starter motor 4 is connected to the starting circuit C1, and a battery charging state S2 (second state) in which the starter motor 4 is connected to the charging circuit C2. Figure 2 shows the engine starting state S1, and the flow of current for starting the engine 3 is shown by a thick line. Figure 3 shows the battery charging state S2, and the flow of current for charging the battery 2 is shown by a thick line. In Figures 2 and 3, the direction of the power flow transmitted by the power transmission unit 6 is indicated by arrows. That is, in Figure 2, the power of the starter motor 4 is transmitted to the engine 3, and in Figure 3, the power of the engine 3 is transmitted to the starter motor 4.

[0029] The vehicle body 101 includes a control unit 1 that controls the switching between the engine starting state S1 and the battery charging state S2, a rectifier 9, and a DC converter 10. The rectifier 9 converts the AC voltage generated by the starter motor 4 into a DC voltage. The DC converter 10 converts the voltage of the power supplied from the rectifier 9. The power converted by the DC converter 10 is used to charge the battery 2.

[0030] The control unit 1 includes an MCU 5 that performs driving control and work control, and a switching unit 8 that switches the connection destination of the starter motor 4. The MCU 5 is a controller that communicates with the radio control transmitter and controls various parts of the vehicle body 101. The MCU 5 performs CAN communication. The MCU 5 is a computer that has a ROM (Read Only Memory) for storing programs, a RAM (Random Access Memory) for temporarily storing data, a storage medium such as an HDD (Hard Disk Drive), a processor such as a CPU (Central Processing Unit), and a communication circuit such as a wireless LAN. The switching unit 8 includes switching units 8U, 8W, and 8V corresponding to the U phase, V phase, and W phase, respectively.

[0031] The starting circuit C1 consists of a battery 2, an MCU 5, a switching unit 8, and wiring connecting them. The battery 2 has a positive terminal and a negative terminal. The MCU 5 has terminals 5a and 5b. The switching units 8U, 8W, and 8V each have terminals 8a and 8b, respectively. The starting motor 4 has terminals 4U, 4V, and 4W connected to each of the three phases.

[0032] The positive terminal of battery 2 is connected to terminal 5a of MCU 5. The negative terminal of battery 2 is grounded. Terminal 5b of MCU 5 is connected to terminal 8b of the switching units 8U, 8V, and 8W, respectively. Terminal 8a of switching unit 8U is connected to terminal 4U of starter motor 4. Terminal 8a of switching unit 8V is connected to terminal 4V of starter motor 4. Terminal 8a of switching unit 8W is connected to terminal 4W of starter motor 4.

[0033] The charging circuit C2 consists of a switching unit 8, a rectifier 9, a DC converter 10, a battery 2, and wiring connecting them. In the battery charging state S2, the starter motor 4 is connected to the MCU 5. The switching units 8U, 8V, and 8W each have a terminal 8c. The rectifier 9 has terminals 9U, 9V, and 9W, as well as a positive terminal and a negative terminal. The DC converter 10 has a positive terminal and a negative terminal on the input side, and a positive terminal and a negative terminal on the output side.

[0034] Terminal 8c of the switching unit 8U is connected to terminal 9U of the rectifier 9. Terminal 8c of the switching unit 8V is connected to terminal 9V of the rectifier 9. Terminal 8c of the switching unit 8W is connected to terminal 9W of the rectifier 9. The positive terminal of the rectifier 9 is connected to the positive input terminal of the DC converter 10. The negative terminal of the rectifier 9 is connected to the positive input terminal of the DC converter 10. The positive output terminal of the DC converter 10 is connected to the positive terminal of the battery 2. The negative output terminal of the DC converter 10 is grounded.

[0035] The switching units 8U, 8V, and 8W each have a relay circuit C3. The relay circuit C3 includes a switch 81 that switches between an engine start state S1 and a battery charging state S2, and a relay unit 82 that switches the destination of switch 81. The switching units 8U, 8V, and 8W each have terminals 8d and 8e. The relay unit 82 is located between terminals 8d and 8e. The MCU 5 has terminal 5c. Terminal 5c is connected to terminal 8d of the switching units 8U, 8V, and 8W. The terminals 5c of the switching units 8U, 8V, and 8W are connected to each other. Terminal 5c is grounded.

[0036] Switch 81 is a normally closed switch. When power is supplied to the relay unit 82, switch 81 connects terminal 8a to terminal 8c. Switch 81 maintains the engine started state S1 when the relay unit 82 is energized. When power is not supplied to the relay unit 82, switch 81 connects terminal 8a to terminal 8b. Switch 81 maintains the battery charged state S2 when the relay unit 82 is not energized.

[0037] The MCU 5 includes a monitoring unit 51 that monitors the state of the starter motor 4, a condition determination unit 52 that determines whether the conditions for switching from the engine starting state S1 to the battery charging state S2 have been met, a calculation unit 53 that performs predetermined calculations, a control unit 54 that controls the starter motor 4 and the switching unit 8, and a storage unit 55 that stores the values ​​monitored by the monitoring unit 51 and the values ​​calculated by the calculation unit 53. The monitoring unit 51 monitors the rotational speed, rotational direction, and number of rotations of the starter motor 4. The rotational speed of the starter motor 4 is the number of times the starter motor 4 rotates per minute. In addition to the rotational speed of the starter motor 4, or instead, the monitoring unit 51 may monitor the rotational speed of the starter motor 4. The rotational direction of the starter motor 4 includes forward rotation, which is the direction in which the starter motor 4 rotates when the starter motor 4 starts the engine 3, and reverse rotation, which is the opposite direction to forward rotation. The number of rotations of the starter motor 4 is the number of times the starter motor 4 has rotated since the start of its operation. Furthermore, the monitoring unit 51 monitors the status of the engine 3 and the starter motor 4 from sensors (not shown) on the vehicle body 101. The monitoring unit 51 also monitors the temperature of the engine 3 and the starter motor 4.

[0038] The condition determination unit 52 determines whether predetermined conditions regarding the rotational state of the starter motor 4 have been met after the starter motor 4 has been driven. The condition determination unit 52 performs a first determination and a second determination. The first determination is whether the rotational speed of the starter motor 4 has become greater than the rotational speed of the motor corresponding to the rotational speed of the engine 3 when the engine 3 is started. The second determination is whether there is an abnormality in the rotational state of the starter motor 4. Specifically, the second determination determines that the rotational state of the starter motor 4 is abnormal when the rotational direction of the starter motor 4 is reversed, and determines that the rotational state of the starter motor 4 is normal when the rotational direction of the starter motor 4 is forward.

[0039] The calculation unit 53 calculates the output value to the starter motor 4. The calculation unit 53 may also calculate the rotational speed of the engine 3 based on the rotational speed of the starter motor 4. The monitoring unit 51 may monitor the rotational speed of the engine 3 calculated by the calculation unit 53 instead of the rotational speed of the starter motor 4. The storage unit 55 stores the rotational speed of the engine 3 at startup as a threshold value. This threshold value is, for example, 2500 [rpm].

[0040] The control unit 54 includes a motor control unit 56 and a circuit control unit 57. The motor control unit 56 controls the drive of the starting motor 4 through the starting circuit C1. The motor control unit 56 supplies power to the starting motor 4 in an amount corresponding to the output value calculated by the calculation unit 53. The circuit control unit 57 controls the switching unit 8 by controlling the on / off switching of the power supply to the relay unit 82. After the starting motor 4 starts to drive, if predetermined conditions regarding the rotation state of the starting motor 4 are met, the circuit control unit 57 controls the switching unit 8 to switch from the engine starting state S1 to the battery charging state S2.

[0041] The circuit control unit 57 controls the switching unit 8 to switch from the engine starting state S1 to the battery charging state S2 when the rotational speed of the starting motor 4, as monitored by the monitoring unit 51, becomes greater than the rotational speed of the motor corresponding to the rotational speed of the engine 3 at startup. The circuit control unit 57 also controls the switching unit 8 to switch from the engine starting state S1 to the battery charging state S2 when the rotational direction of the starting motor 4 is reversed (the rotational direction is reversed).

[0042] Next, the control method of the control unit 1 will be explained with reference to Figures 4 and 5. The control method of the agricultural machine 100 is started, for example, when the MCU 5 receives a start command transmitted from the radio control transmitter. As shown in Figure 4, first the MCU 5 performs ADC processing (step S01). More specifically, the monitoring unit 51 monitors measured values ​​regarding the state of the engine 3 and the state of the starter motor 4. Next, the MCU 5 checks the CAN message (step S02). More specifically, the MCU 5 checks whether the CAN message contains a request to drive the starter motor 4.

[0043] Next, the monitoring unit 51 monitors the status of the starting motor 4 (step S03). Specifically, the monitoring unit 51 monitors the rotational speed and rotational direction of the starting motor 4. The rotational speed of the starting motor 4 monitored by the monitoring unit 51 is stored in the storage unit 55.

[0044] Next, the MCU 5 performs the drive process for the starter motor 4 (step S04). As shown in Figure 5, the condition determination unit 52 determines whether or not there is a request to drive the starter motor 4 in the CAN message received by the MCU 5 (step S41). If the condition determination unit 52 determines that there is a request to drive the starter motor 4 (step S41: YES), the condition determination unit 52 determines whether or not the rotational speed of the starter motor 4 is less than or equal to the rotational speed of the starter motor 4 corresponding to the rotational speed of the engine 3 when the engine 3 is started (step S42).

[0045] If the condition determination unit 52 determines that the rotational speed of the starter motor 4 is less than or equal to the rotational speed of the starter motor 4 corresponding to the rotational speed of the engine 3 when the engine 3 is started (step S42: YES), the condition determination unit 52 determines whether or not there is an abnormality in the rotational state of the starter motor 4 (step S43). If the condition determination unit 52 determines that there is no abnormality in the rotational state of the starter motor 4 (step S43: YES), the circuit control unit 57 maintains the engine start state S1 (step S44). Subsequently, the calculation unit 53 calculates the output value for the starter motor 4 from the motor control unit 56 (step S45).

[0046] If the condition determination unit 52 determines that there is no request to drive the starter motor 4 (step S41: NO), if the condition determination unit 52 determines that the rotational speed of the starter motor 4 is greater than the rotational speed of the motor corresponding to the rotational speed of the engine 3 when the engine 3 is started (step S42: NO), or if the condition determination unit 52 determines that there is an abnormality in the rotational state of the starter motor 4 (step S43: NO), the circuit control unit 57 controls the switching unit 8 to switch from the engine starting state S1 to the battery charging state S2 (step S46). An abnormality in the rotational state of the starter motor 4 may be caused by, for example, an abnormal rotation of the engine 3 (kickback, i.e., a kickback). In this case, the system is made safer by switching to the battery charging state S2 without continuing to start the engine using the starter motor 4. Subsequently, the calculation unit 53 sets the output value of the motor control unit 56 to zero (step S47).

[0047] Next, the motor control unit 56 outputs the output value calculated by the calculation unit 53 to the starting motor 4 (step S48). Returning to Figure 4, the MCU 5 performs a system reset SWDT check (step S05). The MCU 5 measures time. If steps S01 to S04 are not completed after a predetermined time has elapsed since the MCU 5 started measuring time, the control method of the control unit 1 is reset. If steps S01 to S04 are completed within a predetermined time since the MCU 5 started measuring time, the MCU 5 resets the measured time and starts measuring time again. The control unit 1 repeatedly executes steps S01 to S05.

[0048] In this embodiment, the control unit 1 enables both the starting of the engine 3 and the charging of the battery 2 using a single starter motor 4. The power transmission unit 6 has a simple configuration consisting of a belt 63, a first pulley 61, and a second pulley 62. Since the starting circuit C1 is connected to the control unit 1, in the engine starting state S1, the control unit 1 may be affected by the power generated by the starter motor 4. After the starter motor 4 starts driving, if predetermined conditions regarding the rotational state of the starter motor 4 are met (for example, the rotational speed of the starter motor 4 reaches a certain level, the engine 3 reaches a certain number of rotations, or a certain amount of time has elapsed since the start of motor driving, etc.), the control unit 1 switches the starter motor 4 to a battery charging state S2 connected to the charging circuit C2. This disconnects the control unit 1 from the starter motor 4 and protects the control unit 54. While the engine 3 is in a stable normal operating state, the battery 2 is charged through the starter motor 4 and the charging circuit C2.

[0049] The control unit 1 includes a monitoring unit 51 that monitors the rotational speed of the starter motor 4. The control unit 54 controls the switching unit 8 to switch from the engine starting state S1 to the battery charging state S2 when the rotational speed of the starter motor 4, as monitored by the monitoring unit 51, becomes greater than the rotational speed of the starter motor 4 corresponding to the rotational speed of the engine 3 when the engine 3 is started. With this configuration, the system can quickly switch to the battery charging state S2 when the rotational speed of the starter motor 4 increases. In other words, the system can switch to the battery charging state S2 before the starter motor 4 generates a large amount of power. Therefore, the control unit 54 can be protected.

[0050] The monitoring unit 51 monitors the rotation direction of the starter motor 4, and the control unit 54 controls the switching unit 8 to switch from the engine starting state S1 to the battery charging state S2 if the rotation direction of the starter motor 4 is reversed. With this configuration, the rotation direction of the engine 3 can be monitored by monitoring the rotation direction of the starter motor 4. If the rotation direction of the starter motor 4 is reversed, the rotation direction of the engine 3 is also reversed, and there is a possibility that the engine 3 is experiencing a rotational abnormality. The control unit 54 controls the switching unit 8 to switch from the engine starting state S1 to the battery charging state S2 if the rotation direction of the starter motor is reversed, so safety can be ensured by switching to the battery charging state S2 without continuing to start the engine 3 with the starter motor 4 while an abnormality is occurring in the engine 3.

[0051] The switching unit 8 has a relay circuit C3 that includes a switch 81 for switching between the engine starting state S1 and the battery charging state S2. With this configuration, the relay circuit C3 switches between the engine starting state and the battery charging state S2, so the engine starting state S1 and the battery charging state S2 can be switched using physical contacts. Therefore, when the system is switched to the battery charging state S2, the flow of power to the control unit 54 can be further suppressed. Thus, the control unit 54 that drives the starter motor 4 can be protected.

[0052] Switch 81 is a normally closed switch that maintains the battery charge state S2 when de-energized. With this configuration, even if power cannot be supplied to the relay circuit C3, the switch 81 maintains the battery charge state S2 when de-energized, so the power generated by the starting motor 4 is less likely to flow to the control unit 54. Therefore, the control unit 54 that drives the starting motor 4 can be protected.

[0053] The agricultural implement 100 comprises an engine 3 whose output power is used by the agricultural implement 100, a starter motor 4 that starts the engine 3 and generates electricity when power is transmitted from the engine 3, a power transmission unit 6 that transmits power between the engine 3 and the starter motor 4, a battery 2 that is charged with electricity generated by the starter motor 4, a starter circuit C1 that starts the engine 3 by being driven by the starter motor 4, a charging circuit C2 that charges the battery 2 with electricity generated by the starter motor 4 using the power of the engine 3, and a control unit 1.

[0054] According to the agricultural machine 100, by applying the control unit 1, it is possible to start the engine 3 and charge the battery 2 with a single starter motor 4 while protecting the control unit 54.

[0055] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. The present invention can be modified in various ways without departing from its spirit. For example, the switch in the switching unit may be a normally closed switch that maintains a first state when no power is supplied. Separate switches may be provided for the starting circuit C1 and the charging circuit C2, respectively.

[0056] The agricultural implement to which control unit 1 is applied does not have to be a mobile type brush cutter. For example, the agricultural implement may be a backpack type brush cutter, a backpack type sprayer, or the like.

[0057] The control unit 1 may be applied to a different implement than the agricultural implement 100. Those skilled in the art will understand, by referring to this specification and drawings and the common technical knowledge in the art to which the present invention pertains, that any work vehicle or implement equipped with an engine and a starter motor that transmit power to each other can solve the same problems as described above.

[0058] The circuit control unit 57 may control the switching unit 8 to switch from the engine starting state S1 to the battery charging state S2 when the recoil starter 7 is operated.

[0059] The circuit control unit 57 (control unit 54) controls the switching unit 8 to switch from the engine starting state S1 to the battery charging state S2 when the recoil starter 7 is operated. With this configuration, the engine 3 can be started without driving the starter motor 4. Furthermore, since the control unit 54 controls the switching unit 8 to switch from the engine starting state S1 to the battery charging state S2 when the recoil starter 7 is operated, the system can be switched to the battery charging state S2 when the engine 3 is started by the recoil starter 7. Therefore, the control unit 54 that drives the starter motor 4 can be protected. [Explanation of Symbols]

[0060] 1...Control unit, 2...Battery, 3...Engine, 4...Starting motor (motor), 6...Power transmission unit, 7...Recoil starter, 8...Switching unit, 51...Monitoring unit, 54...Control unit, 81...Switch, 100...Agricultural implement, C1...Starting circuit, C2...Charging circuit, C3...Relay circuit, S1...Engine starting state (first state), S2...Battery charging state (second state).

Claims

1. A control unit (1) applied to a work machine comprising an engine (3), a motor (4) connected to an engine (3), a starting circuit (C1) that starts the engine (3) by driving the motor (4), and a charging circuit (C2) that charges a battery (2) with electricity generated by the motor (4) using the power of the engine (3), A control unit (54) controls the drive of the motor (4) through the starting circuit (C1), The system includes a switching unit (8) that switches the motor (4) from a first state (S1) in which it is connected to the starting circuit (C1) to a second state (S2) in which it is connected to the charging circuit (C2), The control unit (54) controls the switching unit (8) to switch from the first state (S1) to the second state (S2) when predetermined conditions regarding the rotation state of the motor (4) are met after the motor (4) starts to be driven.

2. The system further includes a monitoring unit (51) for monitoring the rotational speed of the motor (4), The control unit (1) according to claim 1, wherein the control unit (54) controls the switching unit (8) to switch from the first state (S1) to the second state (S2) when the motor (4), as monitored by the monitoring unit (51), becomes greater than the rotational speed of the motor (4) corresponding to the rotational speed of the engine (3) when the engine (3) is started.

3. The monitoring unit (51) monitors the rotation direction of the motor (4), The control unit (1) according to claim 2, wherein the control unit (54) controls the switching unit (8) to switch from the first state (S1) to the second state (S2) when the rotation direction of the motor (4) is reversed.

4. The control unit (1) according to any one of claims 1 to 3, wherein the switching unit (8) has a relay circuit (C3) including a switch (81) for switching between the first state (S1) and the second state (S2).

5. The control unit (1) according to claim 4, wherein the switch (81) is a normally closed switch that maintains the second state (S2) when not energized.

6. An engine (3) whose output power is at least partially used for agricultural work, The engine (3) is started, and a motor (4) receives power from the engine (3) to generate electricity. A power transmission unit (6) that transmits power from the engine (3) and the motor (4) to each other, The battery (2) is charged with the power generated by the motor (4), A starting circuit (C1) that starts the engine (3) by driving the motor (4), A charging circuit (C2) charges the battery (2) with electricity generated by the motor (4) using the power of the engine (3), A farm implement (100) comprising a control unit (1) according to any one of claims 1 to 3.

7. The engine (3) is further equipped with a recoil starter (7) for starting the engine. The agricultural implement (100) according to claim 6, wherein the control unit (54) controls the switching unit (8) to switch from the first state (S1) to the second state (S2) when the recoil starter (7) is operated.

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