Work equipment

Abstract

Provided is a work machine in which a substrate that comprises a plurality of relays for switching between a delta connection and a star connection is disposed at a suitable location. A stator substrate 27 comprises: relays RY1–RY3 that turn on if a stator coil connection is a delta connection; and relays RY4, RY5 that turn on if the stator coil connection is a star connection. The stator substrate 27 is disposed at one end section of the stator in a motor shaft direction. A U-phase power source line connection section 67U, a V-phase power source line connection section 67V, and a W-phase power source line connection section 67W are disposed with mutual separation in a motor circumferential direction. The relay RY1 is located between the U-phase power source line connection section 67U and the V-phase power source line connection section 67V; the relays RY2, RY4 are located between the V-phase power source line connection section 67V and the W-phase power source line connection section 67W; and the relays RY3, RY5 are located between the W-phase power source line connection section 67W and the U-phase power source line connection section 67U.

Description

Technical Field

[0001] The present invention relates to a working machine.

Background Art

[0002] Patent Document 1 discloses an electric tool as a working machine in which the winding connection method of a motor can be switched between series connection and parallel connection in accordance with the type (power supply voltage) of a connected power supply. Further, Patent Document 1 discloses that a substrate mounted with a relay for switching the connection method is attached to an end portion of the motor (an end portion of a stator).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0004] The present inventor has recognized that the following problems arise when introducing a connection switching technique that enables switching of a winding connection method between delta connection and star connection into a working machine. · Problem 1: To provide a working machine in which a substrate provided with a plurality of relays for switching between delta connection and star connection is arranged at an appropriate position. · Problem 2: To provide a working machine that can be easily assembled even when the substrate provided with the plurality of relays for switching between delta connection and star connection is provided at the end portion of the stator. · Problem 3: To provide a working machine having a configuration that can withstand a large current while the plurality of relays for switching between delta connection and star connection are provided on the substrate. · Problem 4: To provide a working machine in which an increase in size is suppressed.

[0005] The present invention aims to solve at least one of the above problems 1 to 4.

Means for Solving the Problems

[0006] One aspect of the present invention is a work machine. This work machine is A motor having a stator containing multiple windings, A drive unit that drives the motor, Multiple relays capable of switching the winding connection method between delta connection and star connection, A second circuit board equipped with the aforementioned multiple relays, Multiple power lines are provided to electrically connect the second substrate and the drive unit, and to serve as power supply paths from the drive unit to the multiple windings. A work machine having, The second substrate is positioned at one end of the stator in the axial direction of the motor, and multiple power supplies to which the multiple power lines are connected are connected. line Having a connecting part, The plurality of power line connection points are arranged spaced apart from each other in the circumferential direction of the motor. The present invention is characterized in that at least one of the multiple relays is located between the multiple power line connection points in the circumferential direction.

[0008] The present invention may also be described as "electric work machine," "power tool," "electric equipment," etc., and such descriptions are also valid embodiments of the present invention. [Effects of the Invention]

[0009] According to the present invention, at least one of the above problems 1 to 4 can be solved. [Brief explanation of the drawing]

[0010] [Figure 1] A left side view of a part of the work machine 1 according to Embodiment 1 of the present invention, shown in cross-section. [Figure 2] (A) is a cross-sectional view of section AA in Figure 1. (B) is an enlarged view of section B in Figure 2(A). [Figure 3] A perspective view of the motor 30 and its surrounding components in the work machine 1. [Figure 4]Top view of the motor 30 and its peripheral configuration. [Figure 5] Upper cross-sectional view of the motor 30 and its peripheral configuration. [Figure 6] View of the stator board 27 of the work machine 1 as seen from the left side. [Figure 7] Circuit block diagram of the work machine 1. [Figure 8] (A) is a circuit diagram of the motor connection circuit 46 in FIG. 7. (B) is a circuit diagram showing the motor connection circuit 46 of FIG. 7 separately on the stator 45 side and the stator board 27 side. [Figure 9] Diagram explaining the winding process of the stator 45. [Figure 10] A circuit diagram showing the energization circuit to each coil of relays RY1 to RY5 shown in FIG. 8, and the connection relationship by the first conductive pattern 91 to the sixth conductive pattern 96 on the stator board 27. [Figure 11] Component arrangement diagram on the left surface of the stator board 27. [Figure 12] A component arrangement diagram on the right surface of the stator board 27, which is a component arrangement diagram viewed from the left side through the stator board 27. [Figure 13] Diagram explaining the wiring pattern of the first layer of the stator board 27. [Figure 14] Diagram explaining the wiring pattern of the second layer of the stator board 27. [Figure 15] Diagram explaining the wiring pattern of the third layer of the stator board 27. [Figure 16] Diagram explaining the wiring pattern of the fourth layer of the stator board 27. [Figure 17] A simplified circuit block diagram of the work machine 1 in the case where the 36V step-down circuit 82 and the 24V step-down circuit 83 shown in FIG. 10 are provided on the inverter board 23, relating to Embodiment 1. [Figure 18] A simplified circuit block diagram in the case where the 36V step-down circuit 82 and the 24V step-down circuit 83 shown in FIG. 10 are provided on the stator board 27, relating to Embodiment 2. [Figure 19] A circuit diagram showing the energization circuit to each coil of relays RY1 to RY5 in Embodiment 3, and the connection relationship by the first conductive pattern 101 to the sixth conductive pattern 106 on the stator board 127. [Figure 20] Component layout diagram for the left side of the stator board 127. [Figure 21] This is a component layout diagram of the right side of the stator board 127, viewed from the left side through the stator board 27. [Figure 22] Diagram illustrating the wiring pattern of the first layer of the stator board 127. [Figure 23] Diagram illustrating the wiring pattern of the second layer of the stator board 127. [Figure 24] Diagram illustrating the wiring pattern of the third layer of the stator board 127. [Figure 25] Diagram illustrating the wiring pattern of the fourth layer of the stator board 127. [Figure 26] A circuit diagram showing the power supply circuit to each coil of relays RY1 to RY5 in Embodiment 4. [Figure 27] A circuit diagram showing the power supply circuit to each coil of relays RY1 to RY5 in Embodiment 5. [Figure 28] Circuit diagram of the motor connection circuit in Embodiment 6. [Figure 29] (A) is an explanatory diagram of the arrangement of the stator coil in Embodiment 7. (B) is an explanatory diagram of the wiring pattern of the stator board 427 in Embodiment 7. [Figure 30] A circuit diagram showing the energizing circuits to each coil of relays RY1 to RY5 in Embodiment 8, and the connection relationships between the first conductive patterns 201 to the sixth conductive patterns 206 on the stator board 527. [Figure 31] (A) is an explanatory diagram of the arrangement of the stator coil in Embodiment 8. (B) is an explanatory diagram of the wiring pattern of the stator board 527 in Embodiment 8. [Modes for carrying out the invention]

[0011] (Embodiment 1) Figures 1 to 17 relate to a work machine 1 according to Embodiment 1 of the present invention. Figures 1 and 2(A) define the mutually orthogonal front-back, up-down, and left-right directions in the work machine 1. The work machine 1 is a tabletop cutting machine (tabletop circular saw).

[0012] The work machine 1 has a base 2, a turntable 3, and a fence 4. The base 2 and turntable 3 constitute the base section. The base 2 is placed on a workbench or the like. The turntable 3 is embedded in the center of the base 2 and is rotatable relative to the base 2 by a pivot axis parallel to the vertical direction. The upper surface of the turntable 3 is the mounting surface (base surface) on which the workpiece, such as wood, is placed. The upper surface of the base 2 and the upper surface of the turntable 3 are substantially flush with each other. The fence 4 is provided on the upper surface of the base 2. By bringing the workpiece into contact with the fence 4, stable cutting work becomes possible.

[0013] The work implement 1 has a holder 5. The holder 5 is connected to the rear end of the turntable 3 via an inclined shaft 6 and rises upward from the rear end of the turntable 3. The inclined shaft 6 is a shaft that is approximately parallel to the upper surface of the turntable 3 and parallel to the side surface of the cutting blade 20. The axis of the inclined shaft 6 and the upper surface of the turntable 3 are at approximately the same position in the vertical direction. The holder 5 can be tilted relative to the turntable 3 by a predetermined angle, for example, within a range of 45 degrees, to the left or right of the inclined shaft 6. The tilted position of the holder 5 can be fixed and released by a clamp lever (not shown).

[0014] The work machine 1 has a cutting section 10. The cutting section 10 is connected to the upper part of the holder 5 via a pivot shaft 9 and extends forward and upward. The pivot shaft 9 is a shaft that is substantially parallel to the rotation axis of the cutting blade 20. The cutting section 10 can swing up and down around the pivot shaft 9. A spring (not shown) is provided around the pivot shaft 9 to bias the cutting section 10 upward relative to the holder 5. Figure 1 shows the cutting section 10 in the upper limit position of its swing. The cutting section 10 is connected to the holder 5 via a slide rail (not shown) and is slidable in the front-rear direction relative to the holder 5 by the support of the slide rail.

[0015] The cutting section 10 has a gear case (saw cover) 11 and a housing 12. The gear case 11 is made of metal, such as aluminum. The gear case 11 covers the upper outer circumference of the cutting blade 20. The housing 12 is made of resin, for example, and is connected to the gear case 11 and located to the left of the gear case 11. The housing 12 has a handle housing 13 and a motor housing 17.

[0016] The grip portion of the handle housing 13 is equipped with a trigger switch 14 (drive operation unit) that allows the operator to switch the motor 30 on and off. The rear of the motor housing 17 is a battery pack mounting section 16, where the battery pack 15 can be attached and detached. The work machine 1 operates on the power of the battery pack 15. As shown in Figure 2(A), the motor housing 17 is formed by combining the motor housing 21 and the cover 22 with screws or the like.

[0017] The motor housing 21 is a non-divided cylindrical body with its central axis parallel to the left-right direction. The left-side opening of the motor housing 21 is covered by a cover 22. The motor housing 21 houses the motor 30 and the stator board 27. An air intake 18 (air vent) is provided on the left side of the cover 22 to take in the cooling air generated by the fan 50, which will be described later.

[0018] The cut section 10 has a motor 30. The motor 30 is a 4-pole, 6-slot brushless motor. The motor 30 has a motor shaft 31, a rotor core 32, a rotor magnet 33, a stator core 34, a left insulator 35, a right insulator 36, and a stator coil 37 (winding).

[0019] The motor shaft 31 extends perpendicular to the side of the cutting blade 20. The left portion of the motor shaft 31 is supported by the left bearing 26. The left bearing 26 is held in the bearing holder portion 25 of the motor housing 21. The right portion of the motor shaft 31 is supported by the right bearing 51.

[0020] The rotor core 32 is substantially cylindrical and is mounted around the motor shaft 31, rotating integrally with the motor shaft 31. The rotor magnets 33 are inserted into and held within the rotor core 32. Four rotor magnets 33 are provided around the rotor core 32 at, for example, 90-degree intervals. As shown in Figure 5, a sensor magnet 42 is provided on the left end face of the rotor core 32. There are four sensor magnets 42, each positioned in the same circumferential position as the rotor magnets 33. The magnetic pole surfaces of the sensor magnets 42 are the face facing the rotor core 32 and the face opposite it. The magnetic field generated by the sensor magnets 42 is detected by the Hall IC 29, which will be described later. The rotor core 32, rotor magnets 33, and sensor magnets 42 constitute the rotor of the motor 30.

[0021] The stator core 34 is held in the motor housing 21. As shown in Figure 9, the stator core 34 has a yoke portion 62 and a teeth portion 63. The yoke portion 62 is a cylindrical portion that coaxially surrounds the rotor core 32. The teeth portion 63 protrudes radially inward from the yoke portion 62. Six teeth portions 63 are provided around the stator core 34 at, for example, 60-degree intervals. A stator coil 37 is wound around each teeth portion 63. There are two stator coils 37 for each of the U-phase, V-phase, and W-phase, and in Figures 8(A), (B), and 9, the stator coils 37 are distinguished as U-phase stator coils U1 and U2, V-phase stator coils V1 and V2, and W-phase stator coils W1 and W2.

[0022] The left insulator 35 is, for example, a molded resin body and is located to the left of the stator core 34, interposed between the stator coil 37 and the stator core 34. As shown in Figure 4, the left insulator 35 acts as a guide for the jumper wire 40 that connects the stator coils 37 of the same phase in the circumferential direction of the motor shaft 31, located to the left of the stator core 34. The left insulator 35 holds the connect plate 41, which will be described later. The right insulator 36 is, for example, a molded resin body and is located to the right of the stator core 34, interposed between the stator coil 37 and the stator core 34. The stator core 34, left insulator 35, right insulator 36, stator coil 37, and connect plate 41 constitute the stator of the motor 30.

[0023] The rotation of the motor 30, that is, the rotation of the motor shaft 31, is transmitted forward by the winding transmission mechanism 52, and is further reduced by the reduction mechanism 53 before being transmitted to the cutting blade 20.

[0024] The cut section 10 has a stator board 27 (sensor board) as a second board. As shown in Figure 3, the stator board 27 is fixed to the left end of the left insulator 35 in a position perpendicular to the motor shaft 31 by, for example, three screws 38. That is, the stator board 27 is positioned at one end of the stator in the axial direction of the motor 30. The stator board 27 is a roughly disc shape with a smaller diameter than the stator of the motor 30.

[0025] Five relays 28 are provided on the left side of the stator board 27. In Figures 8(A) and 8(B), the five relays are distinguished as relays RY1 to RY5. As shown in Figure 5, the relay 28 is turned on by passing current through a relay coil 56 wound around an iron core 55, which serves as a magnetic core, causing a movable contact 59 to contact a fixed contact 60. When the current to the relay coil 56 is stopped, the movable contact 59 separates from the fixed contact 60 due to the elastic force of the leaf spring 58, and the relay 28 turns off. The relay 28 here is a through-hole mounting type. That is, the terminals of the relay 28 are electrically connected to the stator board 27 by soldering or the like, passing through the through-holes of the stator board 27.

[0026] As shown in Figures 5 and 6, a Hall IC 29, which serves as a magnetic sensor, is provided on the right side of the stator board 27, that is, on the side of the stator board 27 opposite to the side on which the relay 28 is mounted. The Hall IC 29 is located inward from the relay 28 in the radial direction of the motor shaft 31. Note that Figure 6 shows the left side of the stator board 27, and the Hall IC 29 provided on the right side of the stator board 27 is indicated by a dashed line. Three Hall ICs 29 are provided at 60-degree intervals in the circumferential direction of the motor shaft 31.

[0027] The electrical connection between the stator board 27 and the stator coils 37 is made by metal connect plates 41, as shown in Figures 3, 4, and 6. The connect plates 41 are, for example, fusing terminals. The connect plates 41 are held in place by, for example, integral molding with the left insulator 35. Six connect plates 41 are provided around the motor shaft 31 at, for example, 60-degree intervals. In Figure 3, each connect plate 41 is shown in an open state before the stator coils 37 are wrapped around or hooked onto it. As shown in Figure 4, jumper wires 40 connecting stator coils 37 of the same phase, or the ends of the stator coils 37, are wrapped around or hooked onto each connect plate 41. Each connect plate 41 is electrically connected to the stator board 27 in a closed state, as shown in Figure 4. In Figures 6 and 9, the six connect plates 41 are distinguished as connect plates 41U1, 41U2, 41V1, 41V2, 41W1, and 41W2, according to the phases of the corresponding stator coils 37.

[0028] The cut section 10 has an inverter board 23 (main board) as the first board and a board case 24 that houses and holds it. The board case 24 is located to the left of the bearing holding section 25. The inverter board 23 is held in the board case 24 in a position perpendicular to the motor shaft 31, to the left of the bearing holding section 25. The inverter board 23 and the board case 24 are located to the left of the motor housing 21 and have dimensions larger than the left opening of the motor housing 21 when viewed from the axial direction of the motor shaft 31. As shown in Figures 2(A) and (B), a switching element 49 for supplying current to the stator coil 37 is provided on the left side of the inverter board 23. The switching element 49 corresponds to the switching elements Q1 to Q6 such as FETs that constitute the inverter circuit 47 shown in Figure 7. Note that the switching element 49 is not shown in Figure 3. In addition, circuit components such as a microcontroller that constitute the calculation unit 80 shown in Figure 7 are also mounted on the inverter board 23, but these circuit components are not shown in Figure 3.

[0029] The electrical connection between the inverter board 23 and the stator board 27 is made by the U-phase power line 43U, the V-phase power line 43V, and the W-phase power line 43W shown in Figure 6. The U-phase power line 43U extends from the interconnection point of the switching elements Q1 and Q4 shown in Figure 7 on the inverter board 23 and is electrically connected to the stator board 27. The V-phase power line 43V extends from the interconnection point of the switching elements Q2 and Q5 shown in Figure 7 on the inverter board 23 and is electrically connected to the stator board 27. The W-phase power line 43W extends from the interconnection point of the switching elements Q3 and Q6 shown in Figure 7 on the inverter board 23 and is electrically connected to the stator board 27.

[0030] The cut section 10 has a fan 50. The fan 50 is a centrifugal fan, mounted on the motor shaft 31 to the right of the stator core 34, and rotates integrally with the motor shaft 31. The flow of cooling air generated by the fan 50 is shown by arrows in Figure 2(A). The cooling air enters the cover 22 from the intake port 18 of the cover 22, cools the inverter board 23 and switching element 49, then flows around to the right of the inverter board 23 to cool the stator board 27 and relay 28, and further cools the motor 30 before being drawn into the fan 50. That is, the relay 28 is located downstream of the switching element 49 in the flow of the cooling air. The gap between the inner edge of the through hole 44 in the center of the stator board 27 shown in Figure 2(B) and the outer surface of the motor shaft 31, and the gap between the notch 39 at the left end of the left insulator 35 shown in Figure 3 and the stator board 27, become air passages through which the cooling air, after cooling the stator board 27 and relay 28, flows towards the motor 30. The cooling air drawn into the fan 50 flows centrifugally, is guided by the inner wall of the housing 12, flows to the right, and is exhausted to the outside of the housing 12 through an exhaust port (not shown).

[0031] Figure 7 is a circuit block diagram of the work machine 1. Figures 8(A) and 8(B) show the specific configuration of the motor connection circuit 46 in Figure 7. The motor connection circuit 46 includes U-phase stator coils U1 and U2, V-phase stator coils V1 and V2, W-phase stator coils W1 and W2, and relays RY1 to RY5. Relays RY1 to RY5 are connection switching units that switch the connections of the U-phase stator coils U1 and U2, V-phase stator coils V1 and V2, and W-phase stator coils W1 and W2 (hereinafter referred to as "stator coil connections") between delta connections and star connections (Y connections), and are examples of second switch units. The nominal heat resistance temperature of relays RY1 to RY5 (hereinafter referred to as "relay heat resistance temperature") is higher than the nominal heat resistance temperature of the switching elements Q1 to Q6 of the inverter circuit 47 (hereinafter referred to as "FET heat resistance temperature").

[0032] When the stator coil is connected in a delta configuration as the first connection, relays RY1 to RY3 are ON (conductive), and relays RY4 and RY5 are OFF (disconnected). When the stator coil is connected in a star configuration as the second connection, relays RY1 to RY3 are OFF (disconnected), and relays RY4 and RY5 are ON (conductive). Relays RY1 to RY3 are relays for delta connections and are examples of the first connection. Relays RY4 and RY5 are relays for star connections and are examples of the second connection.

[0033] The inverter circuit 47 is a drive unit that converts the DC output of the battery pack 15 into AC and supplies it to the motor connection circuit 46 to drive the motor 30. The inverter circuit 47 includes three-phase bridge-connected switching elements Q1 to Q6 such as FETs and IGBTs. Switching elements Q1 to Q6 are examples of the first switch section. The resistor 48 is provided in the path of the current flowing through the motor connection circuit 46 (hereinafter referred to as "motor current"). The current detection circuit 71 detects the motor current by the voltage drop across the resistor 48 and transmits it to the calculation unit 80. The voltage detection circuit 72 detects the output voltage of the battery pack 15 (hereinafter referred to as "battery voltage") and transmits it to the calculation unit 80. The manipulated variable detection circuit 73 detects the on / off state and manipulated variable of the trigger switch 14 and transmits it to the calculation unit 80.

[0034] The thermistor 75, acting as a temperature sensing element, is provided on the inverter board 23 and is located near one of the switching elements Q1 to Q6. It outputs a signal corresponding to the temperature of the switching element (hereinafter referred to as "FET temperature"). The temperature detection circuit 74 detects the temperature of the switching element based on the signal from the thermistor 75 and transmits it to the calculation unit 80. Note that the switching elements Q1 to Q6 are identical elements with common on-resistance and heat resistance temperatures, and their temperature changes are substantially the same. Therefore, it is sufficient to monitor the temperature change of just one of the switching elements Q1 to Q6.

[0035] The rotor position detection circuit 76 detects the rotor rotation position of the motor 30 based on the output signal of the Hall IC 29 and transmits it to the calculation unit 80. The rotation speed detection circuit 77 detects the rotation speed of the motor 30 (hereinafter referred to as "motor rotation speed") based on the output signal of the rotor position detection circuit 76 and transmits it to the calculation unit 80. The relay drive circuit 78 controls the on / off state of the relays 28 (relays RY1 to RY5) according to the control of the calculation unit 80. The control signal output circuit 79 controls the on / off state of the switching elements Q1 to Q6 of the inverter circuit 47 according to the control of the calculation unit 80.

[0036] The calculation unit 80 is a control unit that controls the overall operation of the work machine 1. The calculation unit 80 monitors the motor current, battery voltage, on / off state and operation amount of the trigger switch 14, FET temperature, rotor rotation position, and motor rotation speed, and controls the drive of the inverter circuit 47 (PWM control) via the control signal output circuit 79 in response to the operation of the trigger switch 14, thereby controlling the drive of the motor 30.

[0037] The calculation unit 80 has an overload protection function (overcurrent protection function) that stops the power supply to the motor 30 by turning off all switching elements Q1 to Q6 even when the trigger switch 14 is ON if the motor current meets the overload protection operating conditions (overcurrent protection operating conditions). The overload protection operating conditions are, for example, when the motor current exceeds the overload protection threshold (overcurrent protection threshold).

[0038] The calculation unit 80 has a high-temperature protection function that, when the FET temperature meets the high-temperature protection operating conditions, turns off all switching elements Q1 to Q6 and stops the power supply to the motor 30, even when the trigger switch 14 is ON. The high-temperature protection operating conditions are, for example, when the FET temperature exceeds a predetermined temperature (high-temperature protection threshold).

[0039] In the overload protection function and the high-temperature protection function, turning off all switching elements Q1 to Q6 to stop the power supply to the motor 30 is an example of controlling the system so that no current flows through relays RY1 to RY5 (the power supply to relays RY1 to RY5 is cut off). The calculation unit 80 may turn off all relays RY1 to RY5 instead of, or in addition to, turning off all switching elements Q1 to Q6.

[0040] When the motor 30 is driven, both the FET temperature and the temperatures of relays RY1 to RY5 (hereinafter referred to as "relay temperature") rise. For this reason, it is conceivable to implement both a control that monitors the FET temperature to prevent it from exceeding the FET's heat resistance temperature, and a control that monitors the relay temperature to prevent it from exceeding the relay's heat resistance temperature. However, if thermistors 75 for FET temperature monitoring and thermistors for relay temperature monitoring are provided separately, it may increase costs, enlarge the stator board 27 for thermistor mounting, and ultimately enlarge the work machine 1.

[0041] Therefore, the work machine 1 is configured such that the FET temperature satisfies the high-temperature protection activation condition before the relay temperature reaches the relay heat resistance temperature. In other words, when the FET temperature exceeds a predetermined temperature (high-temperature protection threshold), the relay temperature is configured to be lower than the relay heat resistance temperature. Under this configuration, the work machine 1 does not have a dedicated thermistor for monitoring the relay temperature, and the calculation unit 80 indirectly controls the relay temperature to not exceed the relay heat resistance temperature by controlling the FET temperature to not exceed the FET heat resistance temperature.

[0042] As shown in Figures 8(A) and (B), the U-phase stator coils U1 and U2 are connected in parallel to each other, the V-phase stator coils V1 and V2 are connected in parallel to each other, and the W-phase stator coils W1 and W2 are connected in parallel to each other. Figure 8(B) shows that the parallel connection (parallel wiring) of the stator coils of each phase is completed on the stator 45 side, that is, it is achieved without relying on the conductive pattern (wiring pattern) of the stator board 27. As a result, only six connect plates 41 are needed, and the complexity of the conductive pattern on the stator board 27 is suppressed.

[0043] Figure 9 is an explanatory diagram of the winding process of the stator 45. In this example, the starting point of the wire that will become the stator coil is wrapped around the connect plate 41U2, the stator coil U2 is wound, it is rotated 180 degrees clockwise in Figure 9 and hooked onto the connect plate 41U1, the stator coil U1 is wound, it is rotated 180 degrees clockwise in Figure 9 and hooked onto the connect plate 41U2. As a result, the U-phase stator coils U1 and U2 are connected in parallel to each other.

[0044] Next, the wire attached to the connect plate 41U2 is routed 60 degrees clockwise in Figure 9, attached to the connect plate 41W1, wound around the stator coil W1, routed 180 degrees clockwise in Figure 9, attached to the connect plate 41W2, wound around the stator coil W2, routed 180 degrees clockwise in Figure 9, and attached to the connect plate 41W1. This connects the W-phase stator coils W1 and W2 in parallel.

[0045] Next, the wire hooked onto the connect plate 41W1 is routed 60 degrees clockwise in Figure 9, hooked onto the connect plate 41V2, and the stator coil V2 is wound around it. The wire is then routed 180 degrees clockwise in Figure 9, hooked onto the connect plate 41V1, and the stator coil V1 is wound around it. The wire is then routed 180 degrees counterclockwise in Figure 9, and the end of the winding is wrapped around the connect plate 41V2. This results in the V-phase stator coils V1 and V2 being connected in parallel.

[0046] The above winding process can be performed using an automatic winding machine (not shown). Next, the unnecessary parts of the wire (the dashed lines in Figure 9), namely the parts that pass between connect plates 41U2 and 41W1, and the parts that pass between connect plates 41W1 and 41V2, are cut and removed. This completes the connection shown within the dashed lines of the stator 45 in Figure 8(B). The jumper wires 40 and each connect plate 41 that connect stator coils of the same phase are examples of common connection parts. In the above winding process, there is no particular limitation on which stator coil to start winding from.

[0047] Figure 10 is a circuit diagram showing the energizing circuits to each coil of relays RY1 to RY5 shown in Figure 8, and the connection relationships between the first conductive patterns 91 to the sixth conductive patterns 96 on the stator board 27.

[0048] The inverter board 23 is equipped with a power supply 81 for the control circuit, a 36V step-down circuit 82 as the first step-down circuit, and a 24V step-down circuit 83 as the second step-down circuit. The power supply 81 for the control circuit generates 5V DC from the battery voltage and supplies it as a power supply voltage to the calculation unit 80 shown in Figure 7, etc., and also supplies it to the stator board 27. The battery voltage is 40V as an example here. The battery voltage is an example of a power supply voltage supplied from an external source.

[0049] The 36V step-down circuit 82 steps down the battery voltage to 36V DC and supplies it to the coils of relays RY1 to RY3. The coils of relays RY1 to RY3 and the delta-side relay switching circuit 85 are connected in series between the output terminal of the 36V step-down circuit 82 and ground. The on / off state of the delta-side relay switching circuit 85 is controlled by relay operation signals from the calculation unit 80 shown in Figure 7. When the delta-side relay switching circuit 85 is on (conducting), a voltage of 12V is applied to the coils of relays RY1 to RY3, and relays RY1 to RY3 are each turned on (conducting). Here, as an example, the coil rated voltage (the optimal voltage applied to the coil to turn on the relay) of relays RY1 to RY3 is set to 12V each. The delta-side relay switching circuit 85 is provided on the stator board 27 and constitutes part of the relay drive circuit 78 shown in Figure 7.

[0050] The 24V step-down circuit 83 steps down the battery voltage to 24V DC and supplies it to the coils of relays RY4 to RY5. The step-down rate of the 24V step-down circuit 83 (40V → 24V) is higher than that of the 36V step-down circuit 82 (40V → 36V). The coils of relays RY4 to RY5 and the star-side relay switching circuit 86 (Y-side relay switching circuit) are connected in series between the output terminal of the 24V step-down circuit 83 and ground. The on / off state of the star-side relay switching circuit 86 is controlled by the relay operation signal from the calculation unit 80 shown in Figure 7. When the star-side relay switching circuit 86 is on (conducting), a voltage of 12V is applied to the coils of relays RY4 to RY5, and relays RY4 to RY5 are turned on (conducting). Here, as an example, the coil rated voltage of relays RY4 to RY5 is assumed to be 12V each. The star-side relay switching circuit 86 is provided on the stator board 27 and constitutes part of the relay drive circuit 78 shown in Figure 7.

[0051] The Hall IC signal detection circuit 84 is a circuit that outputs the signals from the three Hall ICs 29 shown in Figure 7 to the inverter board 23.

[0052] As shown in Figures 10 and 13 to 16, the stator substrate 27 is provided with a ground pattern 87 and first to sixth conductive patterns 91 to 96, which are patterns through which high currents flow. In Figures 13 to 16, the ground pattern 87 and first to sixth conductive patterns 91 to 96 are shown by hatching. The ground pattern 87 and first to sixth conductive patterns 91 to 96 are conductive patterns for high currents.

[0053] The first conductive pattern 91 electrically connects the U-phase power line connection section 67U to which the U-phase power line 43U is connected, one end of the relay RY1, and the connect plate 41U1 to each other.

[0054] The second conductive pattern 92 electrically connects the V-phase power line connection section 67V to which the V-phase power line 43V is connected, one end of the relay RY2, and the connect plate 41V1 ​​to each other.

[0055] The third conductive pattern 93 electrically connects the W-phase power line connection section 67W to which the W-phase power line 43W is connected, one end of the relay RY3, and the connect plate 41W1 to each other.

[0056] The fourth conductive pattern 94 electrically connects the other end of relay RY1, the connect plate 41W2, and one end of relay RY5 to each other.

[0057] The fifth conductive pattern 95 electrically connects the other end of relay RY2, the connect plate 41U2, and one end of relay RY4 to each other.

[0058] The sixth conductive pattern 96 electrically connects the other end of each of the relays RY3 to RY5 to the connect plate 41V2.

[0059] As shown in Figures 13 to 16, the ground pattern 87 and the first to sixth conductive patterns 91 to 96 are provided across the first (left side), second, third, and fourth (right side) conductive layers of the stator substrate 27, overlapping each other via insulating layers and electrically connected to each other via through-holes. The pattern shapes of the ground pattern 87 and the first to sixth conductive patterns 91 to 96 (as viewed from a direction perpendicular to the stator substrate 27) are identical and overlapping in the first to third layers. In the fourth layer, some conductive patterns are removed compared to the first to third layers due to the provision of conductive patterns for signals.

[0060] Figure 11 is a component layout diagram of the left side of the stator board 27.

[0061] The U-phase power line connection section 67U, the V-phase power line connection section 67V, and the W-phase power line connection section 67W are arranged spaced apart from each other in the circumferential direction of the motor 30.

[0062] In the circumferential direction of the motor 30, relay RY1 is located between the U-phase power line connection 67U and the V-phase power line connection 67V, relays RY2 and RY4 are located between the V-phase power line connection 67V and the W-phase power line connection 67W, and relays RY3 and RY5 are located between the W-phase power line connection 67W and the U-phase power line connection 67U. In other words, in the circumferential direction of the motor 30, at least one of relays RY1 to RY5 is located between the U-phase power line connection 67U, the V-phase power line connection 67V, and the W-phase power line connection 67W, respectively.

[0063] In the circumferential direction of the motor 30, relays RY2, RY4, RY3, RY5, and RY1 are arranged in that order. That is, relays RY1 to RY3, which are for delta connection, and relays RY4 to RY5, which are for star connection, are arranged alternately in the circumferential direction of the motor 30.

[0064] Relays RY1 and RY3 have their longitudinal directions approximately parallel to the radial direction of the motor 30. Relays RY2, RY4, and RY5 have their longitudinal directions approximately parallel to the circumferential direction of the motor 30. In the circumferential direction of the motor 30, relays RY1 and RY5 are adjacent to each other, relays RY3 and RY4 are adjacent to each other, and relays RY3 and RY5 are adjacent to each other. In other words, relays whose longitudinal directions are approximately parallel to the radial direction of the motor 30 and relays whose longitudinal directions are approximately parallel to the circumferential direction of the motor 30 are adjacent to each other in the circumferential direction of the motor 30.

[0065] Figure 12 is a component layout diagram of the right side of the stator board 27, viewed from the left side through the stator board 27. Three Hall ICs 29 are arranged in the circumferential direction of the motor 30. Two of the Hall ICs 29 are located within the range of relays RY2 and RY4 in the circumferential direction of the motor 30, and are located inside relays RY2 and RY4 in the radial direction of the motor 30.

[0066] Figure 17 is a simplified circuit block diagram of the work machine 1 when the 36V step-down circuit 82 and 24V step-down circuit 83 shown in Figure 10 are provided on the inverter board 23. When the 36V step-down circuit 82 and 24V step-down circuit 83 are provided on the inverter board 23, space for the 36V step-down circuit 82 and 24V step-down circuit 83 is not required on the stator board 27, so the area of ​​the ground pattern 87 and the first conductive patterns 91 to the sixth conductive patterns 96 can be increased (the pattern width can be increased), and the allowable current value can be increased.

[0067] This embodiment provides the following effects and benefits.

[0068] (1) Relays RY1 to RY5 for switching the stator coil connection between a delta connection as the first connection and a star connection are provided on the stator board 27, and the stator board 27 is positioned at one end of the stator in the axial direction of the motor 30. Therefore, it is possible to provide a work machine 1 in which the stator board 27 equipped with relays RY1 to RY5 for switching between delta and star connections is positioned in an appropriate location.

[0069] (2) The U-phase power line connection section 67U, the V-phase power line connection section 67V, and the W-phase power line connection section 67W are spaced apart from each other in the circumferential direction of the motor 30, with relay RY1 located between the U-phase power line connection section 67U and the V-phase power line connection section 67V, relays RY2 and RY4 located between the V-phase power line connection section 67V and the W-phase power line connection section 67W, and relays RY3 and RY5 located between the W-phase power line connection section 67W and the U-phase power line connection section 67U. As a result, each of the U-phase power line connection section 67U, V-phase power line connection section 67V, and W-phase power line connection section 67W is positioned close to the relay to which it will be connected from among relays RY1 to RY5. Therefore, the ground pattern 87 and each of the first conductive patterns 91 to the sixth conductive patterns 96 can be made to have the same shape and overlap across the first to third layers of the stator board 27, and can be electrically connected to each other. Therefore, even though the outer diameter of the stator board 27 is limited by the inner diameter of the motor housing 21, it is possible to increase the effective pattern width (product of the pattern width of each layer and the number of layers) of the ground pattern 87 and the first conductive patterns 91 to the sixth conductive patterns 96, through which high currents flow, while mounting relays RY1 to RY5. Thus, it becomes possible to reduce power loss in the stator board 27 and increase the allowable current value of the stator board 27. In addition, it is easier to secure the pattern distance (distance between different potentials) of the ground pattern 87 and the first conductive patterns 91 to the sixth conductive patterns 96 through which high currents flow.

[0070] (3) The coils of relays RY1 to RY3 are connected in series with each other and receive power from the 36V step-down circuit 82. Similarly, the coils of relays RY4 to RY5 are connected in series with each other and receive power from the 24V step-down circuit 83. Therefore, the step-down range of the 36V step-down circuit 82 and the 24V step-down circuit 83 is smaller compared to a step-down circuit that steps down the battery voltage to 12V, which is the coil rating voltage of one relay. Thus, power consumption and heat generation due to step-down are suppressed, and the 36V step-down circuit 82 and the 24V step-down circuit 83 can be made smaller.

[0071] (4) Relays RY1 to RY5 are arranged such that relays whose longitudinal direction is approximately parallel to the radial direction of the motor 30 and relays whose longitudinal direction is approximately parallel to the circumferential direction of the motor 30 are adjacent to each other in the circumferential direction of the motor 30. Therefore, compared to cases where the longitudinal directions of all relays are parallel to the circumferential direction of the motor 30, or parallel to the radial direction of the motor 30, or parallel to each other, the layout of each conductive pattern and through holes for screw fastening on the stator board 27 becomes easier.

[0072] (5) A 36V step-down circuit 82 and a 24V step-down circuit 83 are provided on the inverter board 23. As a result, space is not required on the stator board 27 for the 36V step-down circuit 82 and the 24V step-down circuit 83. Therefore, the area of ​​the ground pattern 87 and the first conductive patterns 91 to the sixth conductive patterns 96 provided on the stator board 27 can be increased (the pattern width can be increased), which makes it possible to reduce power loss and increase the allowable current value.

[0073] (6) As shown in Figures 8(B) and 9, the parallel connections of the U-phase stator coils U1 and U2 (hereinafter referred to as "U-phase parallel connection"), the parallel connections of the V-phase stator coils V1 and V2 (hereinafter referred to as "V-phase parallel connection"), and the parallel connections of the W-phase stator coils W1 and W2 (hereinafter referred to as "W-phase parallel connection") are each completed on the stator 45 side, without relying on the conductive pattern of the stator board 27. Therefore, compared to the case in which the connections between stator coils in each parallel connection are configured by the conductive pattern of the stator board 27, the number of connect plates 41 is reduced, the complexity of the conductive pattern of the stator board 27 is suppressed, and the number of conductive patterns through which large currents flow is reduced. As a result, the stator board 27 can be made smaller, and cost increases and product size increases are suppressed. On the other hand, the interconnection configuration between the U-phase parallel connection, the V-phase parallel connection, and the W-phase parallel connection, i.e., the stator coil connection, is not fixed on the stator 45 side, so the stator coil connection can be dynamically switched by relays RY1 to RY5 provided on the stator board 27.

[0074] (7) As shown in Figure 9, the stator winding process is efficient because all slots are wound at once and then the unnecessary parts are removed. In addition, the connect plate 41 allows for the connection of stator coils of the same phase while also providing electrical connection to the stator board 27, thus suppressing an increase in the number of components and simplifying the structure.

[0075] (8) As shown in Figure 2(A), the switching element 49 is positioned upwind of the cooling airflow above the relay 28. Therefore, the cooling airflow can cool the high-heat-generating switching element 49 before it cools the relay 28 and its temperature rises, effectively suppressing the rise in FET temperature.

[0076] (9) The motor housing 21 that holds the stator core 34 is a single (non-divided) component. Therefore, compared to the case where the motor housing 21 has a two-part structure, for example, the coaxial accuracy between the bearing holding portion 25 of the motor housing 21 and the stator core 34 is improved, and the coaxial accuracy between the motor shaft 31 and the stator core 34 is improved.

[0077] (Embodiment 2) Figure 18 is a simplified circuit block diagram relating to Embodiment 2, in which the 36V step-down circuit 82 and the 24V step-down circuit 83 shown in Figure 10 are provided on the stator board 27. When the 36V step-down circuit 82 and the 24V step-down circuit 83 are provided on the stator board 27, the circuits constituting the winding switching function are consolidated on the stator board 27, making it easier to deploy the stator board 27 as a board that consolidates the winding switching function to various models (the versatility of the stator board 27 is increased). In addition, the wiring between the stator board 27 and the inverter board 23 can be reduced. Other aspects of this embodiment are the same as those of Embodiment 1, and it provides the same effects as Embodiment 1.

[0078] (Embodiment 3) Figures 19 to 25 relate to Embodiment 3 of the present invention. The differences from Embodiment 1 will be explained below.

[0079] Figure 19 is a circuit diagram showing the energizing circuits to each coil of relays RY1 to RY5 in Embodiment 3, and the connection relationships between the first conductive patterns 101 to the sixth conductive patterns 106 on the stator board 127.

[0080] As shown in Figures 19 and 22-25, the stator substrate 127 is provided with first conductive patterns 101 to 6th conductive patterns 106 and a ground pattern 107, which are patterns through which large currents flow. In Figures 22-25, the first conductive patterns 101 to 6th conductive patterns 106 and the ground pattern 107 are shown by hatching.

[0081] The first conductive pattern 101 electrically connects the U-phase power line connection section 67U to which the U-phase power line 43U is connected, one end of the relay RY1, and the connect plate 41U1 to each other.

[0082] The second conductive pattern 102 electrically connects the V-phase power line connection section 67V to which the V-phase power line 43V is connected, one end of the relay RY2, and the connect plate 41V1 ​​to each other.

[0083] The third conductive pattern 103 electrically connects the W-phase power line connection section 67W to which the W-phase power line 43W is connected, one end of the relay RY3, and the connect plate 41W1 to each other.

[0084] The fourth conductive pattern 104 electrically connects the other ends of relays RY1, RY4, and RY5 to the connect plate 41W2.

[0085] The fifth conductive pattern 105 electrically connects the other end of relay RY2, the connect plate 41U2, and one end of relay RY4 to each other.

[0086] The sixth conductive pattern 106 electrically connects the other end of relay RY3, the connect plate 41V2, and one end of relay RY5 to each other.

[0087] As shown in Figure 22, the first conductive pattern 101 and the third conductive pattern 103 are provided on the first layer (left side) of the stator substrate 127. As shown in Figure 23, the second conductive pattern 102, the fourth conductive pattern 104, the fifth conductive pattern 105, and the sixth conductive pattern 106 are provided on the second layer of the stator substrate 127.

[0088] As shown in Figures 22 and 23, the first conductive pattern 101 of the first layer and the fourth conductive pattern 104 of the second layer partially overlap each other with an insulating layer in between. Also, the third conductive pattern 103 of the first layer and the second conductive pattern 102, the fourth conductive pattern 104, and the sixth conductive pattern 106 of the second layer partially overlap each other with an insulating layer in between.

[0089] As shown in Figures 22 to 25, the ground pattern 107 is provided across the first to fourth layers of the stator substrate 127, and is electrically connected to each other by through-holes in the overlapping portions separated by the insulating layer. As shown in Figure 24, the third layer is entirely covered by the ground pattern 107, except for areas where insulation from the ground pattern 107 is required. As shown in Figure 25, the fourth layer is provided with conductive patterns for signals in addition to the ground pattern 107.

[0090] Figure 20 is a component layout diagram of the left side of the stator board 127.

[0091] The U-phase power line connection section 67U, the V-phase power line connection section 67V, and the W-phase power line connection section 67W are arranged in close proximity to each other in the circumferential direction of the motor 30. In the circumferential direction of the motor 30, relays RY2, RY4, RY5, RY3, and RY1 are arranged in order, with the U-phase power line connection section 67U, the V-phase power line connection section 67V, and the W-phase power line connection section 67W located between relays RY1 and RY2. In the circumferential direction of the motor 30, relays RY1 to RY3 are positioned close to the U-phase power line connection section 67U, the V-phase power line connection section 67V, and the W-phase power line connection section 67W, while relays RY4 and RY5 are positioned further away from the U-phase power line connection section 67U, the V-phase power line connection section 67V, and the W-phase power line connection section 67W. The relative positions of relays RY1-RY3 and relays RY4 and RY5 with respect to the U-phase power line connection 67U, V-phase power line connection 67V, and W-phase power line connection 67W may be reversed.

[0092] Relays RY1-RY3 and RY5 have their longitudinal directions approximately parallel to the circumferential direction of the motor 30. Relay RY4 has its longitudinal direction approximately parallel to the radial direction of the motor 30. In the circumferential direction of the motor 30, relays RY2 and RY4 are adjacent to each other, and relays RY4 and RY5 are adjacent to each other. In other words, relays whose longitudinal direction is approximately parallel to the radial direction of the motor 30 and relays whose longitudinal direction is approximately parallel to the circumferential direction of the motor 30 are adjacent to each other in the circumferential direction of the motor 30.

[0093] Figure 21 is a component layout diagram of the right side of the stator board 127, viewed from the left side through the stator board 127. Three Hall ICs 29 are arranged in the circumferential direction of the motor 30. Two of the Hall ICs 29 are located within the range of relays RY1 and RY2 in the circumferential direction of the motor 30, and are located inside relays RY1 and RY2 in the radial direction of the motor 30.

[0094] In this embodiment, the effective pattern width of the first conductive patterns 101 to the sixth conductive patterns 106 is smaller than that of the first conductive patterns 91 to the sixth conductive patterns 96 in Embodiment 1. On the other hand, since the U-phase power line connection section 67U, the V-phase power line connection section 67V, and the W-phase power line connection section 67W are arranged in close proximity to each other in the circumferential direction of the motor 30, the U-phase power line 43U, the V-phase power line 43V, and the W-phase power line 43W are arranged in a concentrated layout. As a result, it is possible to suppress the difficulty of connecting the U-phase power line 43U, the V-phase power line 43V, and the W-phase power line 43W to the inverter board 23 while mounting relays RY1 to RY5 on the stator board 127, and thus suppress the deterioration of assembly ease. Other aspects of this embodiment are the same as in Embodiment 1 and produce the same effects.

[0095] (Embodiment 4) Figure 26 is a circuit diagram showing the energization circuit to each coil of relays RY1 to RY5 in Embodiment 4. The differences from Embodiment 1 will be explained below.

[0096] The inverter board 123 is the same as the inverter board 23 in Figure 10, but with the 36V step-down circuit 82 replaced by a 12V step-down circuit 90. The 12V step-down circuit 90 steps down the battery voltage to 12V DC and supplies it to the coil of relay RY1. In this embodiment, the 24V step-down circuit 83 corresponds to the first step-down circuit, and the 12V step-down circuit 90 corresponds to the second step-down circuit.

[0097] The stator board 227 differs from the stator board 27 in Figure 10 in that the connection relationships of the coils of relays RY1 to RY5 are reversed. The coil of relay RY1 and the delta-side relay switching circuit 85 are connected in series between the output terminal of the 12V step-down circuit 90 and ground. The coils of relays RY2 to RY3 and the delta-side relay switching circuit 85 are connected in series between the output terminal of the 24V step-down circuit 83 and ground, and the coils of relays RY4 to RY5 and the star-side relay switching circuit 86 (Y-side relay switching circuit) are connected in parallel with relays RY2, etc. Since relays RY2 to RY3 and relays RY4 to RY5 are never turned on simultaneously, relays RY2 to RY3 and relays RY4 to RY5 share the 24V step-down circuit 83 as the power source for their coils.

[0098] According to this embodiment, the 36V step-down circuit 82 of Embodiment 1 is replaced with a 12V step-down circuit 90, resulting in a larger step-down range, but it can effectively handle a decrease in battery voltage. Specifically, although the battery voltage fluctuates in the range of 30 to 40V depending on the remaining charge of the battery pack 15, the 12V step-down circuit 90 can output 12V even when the battery voltage falls below 36V, thus effectively handling a decrease in battery voltage. Furthermore, since the coils of relays RY2 to RY3 and relays RY4 to RY5 receive power from a common 24V step-down circuit 83, the number of step-down circuits can be kept from increasing. Other aspects of this embodiment are the same as those of Embodiment 1, and it provides the same effects and advantages.

[0099] (Embodiment 5) Figure 27 is a circuit diagram showing the power supply circuit to each coil of relays RY1 to RY5 in Embodiment 5. The differences from Embodiment 4 will be explained below.

[0100] Inverter board 223 is the same as inverter board 123 in Figure 26, but with the 24V step-down circuit 83 replaced by 12V step-down circuits 98 and 99. The 12V step-down circuits 98 and 99 step down the battery voltage to 12V DC and supply it to the coils of relays RY2 to RY5. In this embodiment, the 12V step-down circuits 98 and 99 correspond to the first and second step-down circuits, and the 12V step-down circuit 90 corresponds to the third step-down circuit.

[0101] The stator board 327 differs from the stator board 227 in Figure 26 in that the connection relationships of the coils of relays RY1 to RY5 have been changed.

[0102] The coil of relay RY2 and the delta-side relay switching circuit 85 are connected in series between the output terminal of the 12V step-down circuit 98 and ground. In addition, the coil of relay RY4 and the star-side relay switching circuit 86 (Y-side relay switching circuit) are connected in series in parallel with relay RY2, etc. Since relays RY2 and RY4 are never turned on at the same time, relays RY2 and RY4 share the 12V step-down circuit 98 as the power source for their coils.

[0103] The coil of relay RY3 and the delta-side relay switching circuit 85 are connected in series between the output terminal of the 12V step-down circuit 99 and ground. In addition, the coil of relay RY5 and the star-side relay switching circuit 86 (Y-side relay switching circuit) are connected in series in parallel with relay RY3, etc. Since relays RY3 and RY5 are never turned on at the same time, relays RY3 and RY5 share the 12V step-down circuit 99 as the power source for their coils.

[0104] According to this embodiment, the 24V step-down circuit 83 of Embodiment 4 is replaced by 12V step-down circuits 98 and 99. Although the step-down range is larger and the number of step-down circuits increases, it can also suitably accommodate the use of a battery pack with a lower rated voltage as a power source, such as a battery pack with a rated voltage of 18V. Other aspects of this embodiment are the same as those of Embodiment 4, and it provides the same effects.

[0105] (Embodiment 6) Figures 28(A) and (B) are circuit diagrams of the motor connection circuit in Embodiment 6. Figure 28(A) shows the delta connection state, and Figure 28(B) shows the star connection (Y connection) state. The following will mainly explain the differences from Embodiment 1. Relay RY6 is a C-contact relay and also performs the functions of relays RY2 and RY4 in Figure 8(A), which are A-contact relays. Relay RY7 is a C-contact relay and also performs the functions of RY1 and RY5 in Figure 8(A), which are A-contact relays. According to this embodiment, the total number of relays can be reduced by using C-contact relays. Also, since only three relays are needed, only one 36V step-down circuit is needed to supply power to the relay coils, thus reducing the number of step-down circuits. Other aspects of this embodiment are the same as those of Embodiment 1 and produce the same effects.

[0106] (Embodiment 7) Figure 29(A) is an explanatory diagram of the arrangement of U-phase stator coils U1, U2, V-phase stator coils V1, V2, and W-phase stator coils W1, W2 in Embodiment 7. Figure 29(B) is an explanatory diagram of the wiring pattern of the stator board 427 in Embodiment 7. The differences from Embodiment 1 will be explained below.

[0107] The arrangement shown in Figure 29(A) is the same as the arrangement of Embodiment 1 shown in Figure 9, but with the positions of the V-phase stator coils V1 and V2 swapped. In the case of the stator coil arrangement shown in Figure 29(A), even if the U-phase power line connection part 67U, the V-phase power line connection part 67V, and the W-phase power line connection part 67W are arranged in close proximity to each other in the circumferential direction of the motor 30, as shown in Figure 29(B), the first conductive pattern 91 to the sixth conductive pattern 96 can be arranged together in a single layer, as in Embodiment 1. Therefore, similar to Embodiment 1, the first conductive pattern 91 to the sixth conductive pattern 96 can be stacked with the same shape across the first to third layers of the stator substrate 427 and electrically connected to each other, thereby reducing power loss in the stator substrate 427 and increasing the allowable current value of the stator substrate 427. In Figure 29(B), the position of the connect plate 41W1 is moved away from the edge of the stator substrate 427, thereby passing the second conductive pattern 92 between the connect plate 41W1 and the edge of the stator substrate 427 and securing the area of ​​the second conductive pattern 92. Other aspects of this embodiment are the same as those of Embodiment 1, and it provides the same effects and advantages.

[0108] (Embodiment 8) Figure 30 is a circuit diagram showing the energizing circuits to each coil of relays RY1 to RY5 and the connection relationships by the first conductive patterns 201 to the sixth conductive patterns 206 on the stator board 527 in Embodiment 8. Figure 31(A) is an explanatory diagram of the arrangement of U-phase stator coils U1 to U3, V-phase stator coils V1 to V3, and W-phase stator coils W1 to W3 in Embodiment 8. Figure 31(B) is an explanatory diagram of the wiring pattern of the stator board 527 in Embodiment 8. The following will mainly explain the differences from Embodiment 1. Embodiment 8 corresponds to the motor 30 of Embodiment 1 with 9 slots.

[0109] The first conductive pattern 201 electrically connects the U-phase power line connection section 67U to which the U-phase power line 43U is connected, one end of the relay RY1, and the connect plate 41U1 to each other.

[0110] The second conductive pattern 202 electrically connects the V-phase power line connection section 67V to which the V-phase power line 43V is connected, one end of the relay RY2, and the connect plate 41V1 ​​to each other.

[0111] The third conductive pattern 203 electrically connects the W-phase power line connection section 67W to which the W-phase power line 43W is connected, one end of the relay RY3, and the connect plate 41W1 to each other.

[0112] The fourth conductive pattern 204 electrically connects the other end of relay RY1, one end of relay RY5, and the connect plate 41W3 to each other.

[0113] The fifth conductive pattern 205 electrically connects the other ends of relays RY2, RY4, and RY5 to the connect plate 41U3.

[0114] The sixth conductive pattern 206 electrically connects the other end of relay RY3, the connect plate 41V3, and one end of relay RY4 to each other.

[0115] As shown in Figure 31(B), the first conductive patterns 201 to the sixth conductive patterns 206 can be arranged in a single layer, similar to Embodiment 1. Therefore, similar to Embodiment 1, the first conductive patterns 201 to the sixth conductive patterns 206 can be stacked in the same shape across the first to third layers of the stator substrate 527 and electrically connected to each other, thereby reducing power loss in the stator substrate 527 and increasing the allowable current value of the stator substrate 527. Other aspects of this embodiment are the same as those of Embodiment 1 and produce the same effects.

[0116] Although the present invention has been described above using embodiments as examples, the present invention is not limited to these embodiments. Various modifications are possible to each of the matters specifically described in the embodiments within the scope of the claims.

[0117] The number of rotor poles, the number of stator slots, the battery voltage, the output voltage of the step-down circuit, etc., which are exemplified as specific numerical values ​​in the embodiments, do not limit the scope of the invention in any way and can be arbitrarily changed to suit the required specifications. The motor 30 may be sensorless driven. That is, the Hall IC 29 may be omitted. The relays RY1 to RY5, which are normally open-contact relays, may be normally closed-contact relays. The work machine of the present invention is not limited to a tabletop cutting machine, but may be other types of cutting machines such as a portable circular saw, or other types of work machines such as a grinder. [Explanation of Symbols]

[0118] 1…Work implement, 2…Base, 3…Turntable, 4…Fence, 5…Holder, 6…Tilting axis, 9…Oscillating axis (shaft), 10…Cutting section (head), 11…Gear case (saw cover), 12…Housing, 13…Handle housing, 14…Trigger switch (drive operation section), 15…Battery pack, 16…Battery pack mounting section, 17…Motor housing, 18…Air intake, 20…Cutting blade (saw blade), 21…Motor housing, 22…Cover, 23…Inverter base Board (1st board), 24...Board case, 25...Bearing holder, 26...Left bearing, 27...Stator board (2nd board), 28...Relay, 29...Hall IC (magnetic sensor), 30...Motor, 31...Motor shaft, 32...Rotor core, 33...Rotor magnet, 34...Stator core, 35...Left insulator, 36...Right insulator, 37...Stator coil, 38...Screw, 39...Notch, 40...Jumper wire, 41,41U1,41U2,41V1,41V2,41W1,41W2…Connect plate, 42…Sensor magnet, 43U…U-phase power line, 43V…V-phase power line, 43W…W-phase power line, 44…Through hole, 45…Stator, 46…Motor connection circuit, 47…Inverter circuit, 48…Resistor, 49…Switching element, 50…Fan, 51…Right bearing, 52…Wound transmission mechanism, 53…Reduction mechanism, 55…Iron core (magnetic core), 56…Relay coil, 58…Leaf spring, 59…Movable contact, 60…Fixed contact, 62…Yoke section, 63…Teeth section, 67U…U-phase power line connection section, 67V…V-phase power line connection Continuation section, 67W...W-phase power line connection section, 71...Current detection circuit, 72...Voltage detection circuit, 73...Operated variable detection circuit, 74...Temperature detection circuit, 75...Thermistor (temperature detection element), 76...Rotor position detection circuit, 77...Rotation speed detection circuit, 78...Relay drive circuit, 79...Control signal output circuit, 80...Calculation unit (control unit), 81...Power supply for control circuit, 82...36V step-down circuit (first step-down circuit), 83...24V step-down circuit (first step-down circuit or second step-down circuit), 84...Hall IC signal detection circuit, 85...Delta-side relay switching circuit, 86...Y-side relay switching Circuit, 87...Ground pattern, 88...Panel board, 89...Battery terminal board, 90...12V step-down circuit (second step-down circuit), 91...First conductive pattern, 92...Second conductive pattern, 93...Third conductive pattern, 94...Fourth conductive pattern, 95...Fifth conductive pattern, 96...Sixth conductive pattern, 98...12V step-down circuit, 99...12V step-down circuit, 101...First conductive pattern, 102...Second conductive pattern, 103...Third conductive pattern, 104...Fourth conductive pattern, 105...Fifth conductive pattern, 106...Sixth conductive pattern, 107...Ground pattern, 123...Inverter board, 127...Stator board, 201...First conductive pattern, 202...Second conductive pattern, 203...Third conductive pattern, 204...Fourth conductive pattern, 205...Fifth conductive pattern, 206...Sixth conductive pattern, 223...Inverter board, 227...Stator board, 327...Stator board, 427...Stator board, 527...Stator board, RY1~RY7...Relays, U1~U3...U-phase stator coils, V1~V3...V-phase stator coils, W1~W3...W-phase stator coils.

Claims

1. A motor having a stator containing multiple windings, A drive unit that drives the motor, Multiple relays capable of switching the winding connection method between delta connection and star connection, A second circuit board equipped with the aforementioned multiple relays, Multiple power lines are electrically connected to the second substrate and the drive unit, and serve as power supply paths from the drive unit to the multiple windings. A work machine having, The second substrate is positioned at one end of the stator in the axial direction of the motor and has a plurality of power line connection portions to which the plurality of power lines are connected. The plurality of power line connection points are arranged spaced apart from each other in the circumferential direction of the motor. In the circumferential direction, at least one of the multiple relays is located between the multiple power line connection points. A work machine characterized by the following features.

2. A work machine according to claim 1, The aforementioned multiple relays are The first relay that turns on when the aforementioned wiring method is a delta connection, It includes a second relay that turns on when the aforementioned wiring configuration is a star connection, The first relay and the second relay are arranged alternately in the circumferential direction. A work machine characterized by the following features.

3. A work machine according to claim 1, A first circuit board equipped with the aforementioned drive unit, It includes a step-down circuit that steps down the power supply voltage supplied from an external source and supplies it to each coil of the plurality of relays, The step-down circuit is arranged on the first substrate. A work machine characterized by the following features.

4. A work machine according to claim 1, The aforementioned multiple relays are When the aforementioned wiring method is a delta connection, a plurality of first relays are turned on, It has a plurality of second relays that turn on when the aforementioned wiring method is a star connection, Each of the coils of the plurality of first relays is connected in series with one another. The coils of the plurality of second relays are connected in series with each other. A work machine characterized by the following features.

5. A work machine according to claim 4, The number of the aforementioned multiple first relays is three. The number of the aforementioned second relays is two. A first step-down circuit that steps down the power supply voltage supplied from an external source and supplies it to each coil of the plurality of first relays, A second step-down circuit that steps down the power supply voltage and supplies it to each coil of the plurality of second relays, the second step-down circuit having a higher step-down rate than the first step-down circuit, A work machine characterized by the following features.

6. A work machine according to claim 1, The second substrate includes a plurality of conductive layers and has a plurality of conductive patterns that electrically connect the plurality of power line connection portions and the plurality of relays. A conductive pattern for electrically connecting any one power line connection and any one relay is provided across two or more layers of the second substrate, overlapping with each other and electrically connected. A work machine characterized by the following features.

7. A work machine according to claim 6, The system includes a plurality of connect plates that electrically connect the plurality of windings and the second substrate, The second substrate has a plurality of conductive patterns that electrically connect the plurality of connect plates and the plurality of relays, A conductive pattern for electrically connecting any one connect plate and any one relay is provided across two or more layers of the second substrate, overlapping with each other and electrically connected. A work machine characterized by the following features.

8. A work machine according to claim 7, The plurality of conductive patterns that electrically connect the plurality of connect plates and the plurality of relays include a conductive pattern that connects to two of the plurality of relays and a conductive pattern that connects to three of the plurality of relays. A work machine characterized by the following features.

9. A work machine according to claim 1, The second substrate has a plurality of power line connection points to which the plurality of power lines are connected, The second substrate is composed of a number of conductive layers, including a first layer provided with a high-current conductive pattern for electrically connecting the plurality of power line connection parts and the plurality of relays, and a second layer provided with a signal conductive pattern different from the high-current conductive pattern. A work machine characterized by the following features.

10. A work machine according to claim 9, The high-current conductive pattern is provided across two or more layers of the second substrate, including the first layer, and overlaps with each other and is electrically connected. A work machine characterized by the following features.

11. A work machine according to claim 1, Two of the aforementioned relays are relays whose longitudinal direction is substantially parallel to the radial direction of the motor, and relays whose longitudinal direction is substantially parallel to the circumferential direction of the motor, and which are adjacent to each other in the circumferential direction. A work machine characterized by the following features.

12. A work machine according to claim 1, It has a step-down circuit that steps down the power supply voltage supplied from an external source and supplies it to each coil of the plurality of relays, The step-down circuit is arranged on the second substrate. A work machine characterized by the following features.

13. A work machine according to claim 1, It has a step-down circuit that reduces the voltage of the power supply supplied from an external source, The aforementioned multiple relays are When the aforementioned wiring method is a delta connection, a plurality of first relays are turned on, It has a plurality of second relays that turn on when the aforementioned wiring method is a star connection, At least one coil of the plurality of first relays and at least one coil of the plurality of second relays receive power from the common step-down circuit. A work machine characterized by the following features.

14. A work machine according to claim 1, The aforementioned multiple relays are Three first relays that turn on when the aforementioned wiring method is a delta connection, It has two second relays that turn on when the aforementioned wiring method is a star connection, The coils of two of the three first relays are connected in series with each other. The coil of the remaining one of the three first relays is connected in parallel to the coils of the two first relays of the three first relays. The coils of the two second relays are connected in series with each other. A work machine characterized by the following features.

15. A work machine according to claim 1, The aforementioned multiple relays are Three first relays that turn on when the aforementioned wiring method is a delta connection, It has two second relays that turn on when the aforementioned wiring method is a star connection, The coils of the three first relays are connected in parallel to each other. The coils of the two second relays are connected in parallel to each other. A work machine characterized by the following features.

Images