ELECTRIC WORK MACHINE

An electric work machine avoids lowering the visibility of a workpiece by an operator. An electric work machine includes a motor, an output unit operable with a rotational force from the motor, a light emitter at least partially surrounding the output unit, an optical member including an outer cylinder located radially outward from the light emitter, and a light transmitter located frontward from the light emitter to allow light emitted from the light emitter to pass through, and a light shield located radially outward from the outer cylinder.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese Patent Application No. 2022-130714, filed on Aug. 18, 2022, the entire contents of which are hereby incorporated by reference.

BACKGROUND

1. Technical Field

The present disclosure relates to an electric work machine.

2. Description of the Background

In the technical field of electric work machines, known lighting systems for power tools are described in U.S. Patent Application Publication No. 2016/0354889 (hereafter, Patent Literature 1).

BRIEF SUMMARY

In Patent Literature 1, the lighting systems for power tools include one or more chip-on-board (COB) light-emitting diodes (LEDs). The COB LEDs emit light with high luminance. When light emitted from the COB LEDs at least partially reaches the eyes of an operator, such light may cause glare to the operator and thus lower the visibility of a workpiece.

One or more aspects of the present disclosure are directed to avoiding lowering the visibility of a workpiece by an operator.

A first aspect of the present disclosure provides an electric work machine, including:a motor;an output unit operable with a rotational force from the motor;a light emitter at least partially surrounding the output unit;an optical member includingan outer cylinder located radially outward from the light emitter, anda light transmitter located frontward from the light emitter, the light transmitter being configured to allow light emitted from the light emitter to pass through; anda light shield located radially outward from the outer cylinder.

The electric work machine according to the above aspect of the present disclosure can avoid lowering the visibility of a workpiece by an operator.

DETAILED DESCRIPTION

One or more embodiments will now be described with reference to the drawings. In the embodiments, the positional relationships between the components will be described using the directional terms such as right and left (or lateral), front and rear (or frontward and rearward), and up and down (or vertical). The terms indicate relative positions or directions with respect to the center of an electric work machine.

Electric Work Machine

FIG.1is a perspective view of an electric work machine1according to an embodiment as viewed from the front.FIG.2is a side view of an upper portion of the electric work machine1.FIG.3is a longitudinal sectional view of the upper portion of the electric work machine1.FIG.4is a horizontal sectional view of the upper portion of the electric work machine1.

The electric work machine1according to the present embodiment is a power tool including a motor6as a power source. A direction parallel to a rotation axis AX of the motor6is referred to as an axial direction for convenience. A direction about the rotation axis AX is referred to as a circumferential direction or circumferentially, or a rotation direction for convenience. A direction radial from the rotation axis AX is referred to as a radial direction or radially for convenience. A position nearer the rotation axis AX in the radial direction, or a radial direction toward the rotation axis AX, is referred to as radially inward for convenience. A position farther from the rotation axis AX in the radial direction, or a radial direction away from the rotation axis AX, is referred to as radially outside or radially outward for convenience. The rotation axis AX in the present embodiment extends in the front-rear direction. A first axial direction is from the rear to the front. A second axial direction is from the front to the rear.

The electric work machine1according to the present embodiment is an impact tool as an example of a power tool. The electric work machine1is hereafter referred to as an impact tool1as appropriate.

The impact tool1according to the present embodiment is an impact driver as an example of a screwing tool. The impact tool1includes a housing2, a rear cover3, a hammer case4, a case cover5, a motor6, a reducer7, a spindle8, a striker9, an anvil10, a tool holder11, a fan12, a battery mount13, a trigger lever14, a forward-reverse switch lever15, a hand mode switch button16, and a light unit18.

The housing2is formed from a synthetic resin. The housing2in the present embodiment is formed from nylon. The housing2includes a left housing2L and a right housing2R. The right housing2R is located on the right of the left housing2L. The left housing2L and the right housing2R are fastened together with multiple screws2S. The housing2includes a pair of housing halves.

The housing2includes a motor compartment21, a grip22, and a battery holder23.

The motor compartment21is cylindrical. The motor compartment21accommodates the motor6, a part of a bearing box24, and a rear portion of the hammer case4.

The grip22protrudes downward from the motor compartment21. The trigger lever14is located in an upper portion of the grip22. The grip22is grippable by an operator.

The battery holder23is connected to the lower end of the grip22. The battery holder23has larger outer dimensions than the grip22in the front-rear direction and in the lateral direction.

The rear cover3is formed from a synthetic resin. The rear cover3is located behind the motor compartment21. The rear cover3accommodates at least apart of the fan12. The fan12is located circumferentially inward from the rear cover3. The rear cover3covers an opening in the rear end of the motor compartment21. The rear cover3is fastened to the rear end of the motor compartment21with screws3S.

The motor compartment21has inlets19. The rear cover3has outlets20. Air outside the housing2flows into an internal space of the housing2through the inlets19, and then flows out of the housing2through the outlets20.

The hammer case4serves as a gear case accommodating the reducer7. The hammer case4accommodates the reducer7, the spindle8, the striker9, and at least a part of the anvil10. The hammer case4is formed from a metal. The hammer case4in the present embodiment is formed from aluminum. The hammer case4is cylindrical.

The hammer case4includes a rear cylinder4A, a front cylinder4B, and an annular portion4C. The front cylinder4B is located frontward from the rear cylinder4A. The rear cylinder4A has a larger outer diameter than the front cylinder4B. The rear cylinder4A has a larger inner diameter than the front cylinder4B. The annular portion4C connects the front end of the rear cylinder4A and the rear end of the front cylinder4B.

The hammer case4connects to a front portion of the motor compartment21. The bearing box24is fastened to a rear portion of the rear cylinder4A. The reducer7is at least partially located inside the bearing box24. The bearing box24includes threads on its outer circumference. The rear cylinder4A has threaded grooves on the inner circumference of the rear portion. The threads on the bearing box24are engaged with the threaded grooves on the rear cylinder4A to fasten the bearing box24and the hammer case4together. The hammer case4is held between the left housing2L and the right housing2R. A part of the bearing box24and the rear portion of the rear cylinder4A are accommodated in the motor compartment21. The bearing box24is fixed to the motor compartment21and the hammer case4.

The case cover5covers at least a part of the surface of the hammer case4. The case cover5in the present embodiment covers the surface of the rear cylinder4A. The case cover5is formed from a synthetic resin. The case cover5in the present embodiment is formed from a polycarbonate resin. The case cover5protects the hammer case4. The case cover5prevents contact between the hammer case4and objects around the impact tool1. The case cover5prevents contact between the operator and the hammer case4.

The motor6is a power source for the impact tool1. The motor6generates a rotational force. The motor6is an electric motor. The motor6is an inner-rotor brushless motor. The motor6includes a stator26and a rotor27. The stator26is supported by the motor compartment21. The rotor27is at least partially located inward from the stator26. The rotor27rotates relative to the stator26. The rotor27rotates about the rotation axis AX extending in the front-rear direction.

The stator26includes a stator core28, a front insulator29, a rear insulator30, and multiple coils31.

The stator core28is located radially outward from the rotor27. The stator core28includes multiple steel plates stacked on one another. The steel plates are metal plates formed from iron as a main component. The stator core28is cylindrical. The stator core28includes multiple teeth to support the coils31.

The front insulator29is located on the front of the stator core28. The rear insulator30is located on the rear of the stator core28. The front insulator29and the rear insulator30are electrical insulating members formed from a synthetic resin. The front insulator29partially covers the surfaces of the teeth. The rear insulator30partially covers the surfaces of the teeth.

The coils31are attached to the stator core28with the front insulator29and the rear insulator30in between. The coils31surround the teeth on the stator core28with the front insulator29and the rear insulator30in between. The coils31and the stator core28are electrically insulated from each other with the front insulator29and the rear insulator30. The coils31are connected to one another with fusing terminals38.

The rotor27rotates about the rotation axis AX. The rotor27includes a rotor core32, a rotor shaft33, a rotor magnet34, and a sensor magnet35.

The rotor core32and the rotor shaft33are formed from steel. In the present embodiment, the rotor core32and the rotor shaft33are integral with each other. The rotor shaft33includes a front portion protruding frontward from the front end face of the rotor core32. The rotor shaft33includes a rear portion protruding rearward from the rear end face of the rotor core32.

The rotor magnet34is fixed to the rotor core32. The rotor magnet34is cylindrical. The rotor magnet34surrounds the rotor core32.

The sensor magnet35is fixed to the rotor core32. The sensor magnet35is annular. The sensor magnet35is located on the front end face of the rotor core32and the front end face of the rotor magnet34.

A sensor board37is attached to the front insulator29. The sensor board37is fastened to the front insulator29with a screw29S. The sensor board37includes an annular circuit board, a magnetic sensor37A, and a resin-molded body37B. The magnetic sensor37A is supported on the circuit board. The resin-molded body37B covers the magnetic sensor37A. The sensor board37at least partially faces the sensor magnet35. The magnetic sensor37A detects the position of the sensor magnet35to detect the position of the rotor27in the rotation direction.

The rotor shaft33includes the rear portion rotatably supported by a rotor bearing39. The rotor bearing39includes a front portion rotatably supported by a rotor bearing40. The rotor bearing39is held by the rear cover3. The rotor bearing40is held by the bearing box24. The front end of the rotor shaft33is located in an internal space of the hammer case4through an opening in the bearing box24.

A pinion gear41is located on the front end of the rotor shaft33. The pinion gear41is connected to at least a part of the reducer7. The rotor shaft33is connected to the reducer7with the pinion gear41.

The reducer7transmits a rotational force from the motor6to the spindle8and the anvil10. The reducer7is accommodated in the rear cylinder4A in the hammer case4. The reducer7includes multiple gears. The reducer7is located frontward from the motor6. The reducer7connects the rotor shaft33and the spindle8together. The rotor27drives the gears in the reducer7. The reducer7transmits rotation of the rotor27to the spindle8. The reducer7rotates the spindle8at a lower rotational speed than the rotor shaft33. The reducer7includes a planetary gear assembly.

The reducer7includes multiple planetary gears42and an internal gear43. The planetary gears42surround the pinion gear41. The internal gear43surrounds the planetary gears42. The pinion gear41, the planetary gears42, and the internal gear43are accommodated in the hammer case4and the bearing box24. Each planetary gear42meshes with the pinion gear41. The planetary gears42are rotatably supported by the spindle8with a pin42P. The spindle8is rotated by the planetary gears42. The internal gear43includes internal teeth that mesh with the planetary gears42. The internal gear43is fixed to the bearing box24. The internal gear43is constantly nonrotatable relative to the bearing box24.

When the rotor shaft33rotates as driven by the motor6, the pinion gear41rotates, and the planetary gears42revolve about the pinion gear41. The planetary gears42revolve while meshing with the internal teeth on the internal gear43. The revolving planetary gears42rotate the spindle8connected to the planetary gears42with the pin42P at a lower rotational speed than the rotor shaft33.

The spindle8rotates with a rotational force from the motor6. The spindle8is located frontward from at least a part of the motor6. The spindle8is located frontward from the stator26. The spindle8is at least partially located frontward from the rotor27. The spindle8is at least partially located in front of the reducer7. The spindle8is rotated by the rotor27. The spindle8rotates with a rotational force from the rotor27transmitted by the reducer7.

The spindle8includes a flange8A and a spindle shaft8B. The spindle shaft8B protrudes frontward from the flange8A. The planetary gears42are rotatably supported by the flange8A with the pin42P. The rotation axis of the spindle8aligns with the rotation axis AX of the motor6. The spindle8rotates about the rotation axis AX.

The spindle8is rotatably supported by a spindle bearing44. The spindle bearing44is held by the bearing box24. The spindle8includes a ring portion8C protruding rearward from the rear of the flange8A. The spindle bearing44is located inward from the ring portion8C. In the present embodiment, the spindle bearing44includes an outer ring connected to the ring portion8C and an inner ring supported by the bearing box24.

The striker9is driven by the motor6. A rotational force from the motor6is transmitted to the striker9through the reducer7and the spindle8. The striker9strikes the anvil10in the rotation direction in response to the rotational force of the spindle8rotated by the motor6. The striker9includes a hammer47, balls48, and a coil spring49. The striker9including the hammer47is accommodated in the hammer case4.

The hammer47is located frontward from the reducer7. The hammer47is accommodated in the rear cylinder4A. The hammer47surrounds the spindle shaft8B. The hammer47is held by the spindle shaft8B. The balls48are between the spindle shaft8B and the hammer47. The coil spring49is supported by the flange8A and the hammer47.

The hammer47is rotated by the motor6. A rotational force from the motor6is transmitted to the hammer47through the reducer7and the spindle8. The hammer47is rotatable together with the spindle8in response to the rotational force of the spindle8rotated by the motor6. The rotation axis of the hammer47and the rotation axis of the spindle8align with the rotation axis AX of the motor6. The hammer47rotates about the rotation axis AX.

The balls48are formed from a metal such as steel. The balls48are between the spindle shaft8B and the hammer47. The spindle8has a spindle groove8D. The spindle groove8D receives at least parts of the balls48. The spindle groove8D is on the outer circumferential surface of the spindle shaft8B. The hammer47has a hammer groove47A. The hammer groove47A receives at least parts of the balls48. The hammer groove47A is on the inner surface of the hammer47. The balls48are between the spindle groove8D and the hammer groove47A. The balls48can roll along the spindle groove8D and the hammer groove47A. The hammer47is movable together with the balls48. The spindle8and the hammer47are movable relative to each other in the axial direction and in the rotation direction within a movable range defined by the spindle groove8D and the hammer groove47A.

The coil spring49generates an elastic force for moving the hammer47forward. The coil spring49is between the flange8A and the hammer47. An annular recess47C is located on the rear surface of the hammer47. The recess47C is recessed frontward from the rear surface of the hammer47. A washer45is received in the recess47C. The rear end of the coil spring49is supported by the flange8A. The front end of the coil spring49is received in the recess47C and supported by the washer45.

The anvil10is an output unit of the impact tool1that operates with a rotational force from the motor6. The anvil10rotates with a rotational force from the motor6. The anvil10is at least partially located frontward from the hammer47. The anvil10has a tool hole10A to receive a tip tool90. The tip tool90is, for example, a screwdriver bit. The anvil10has the tool hole10A in its front end. The tip tool90is attached to the anvil10. The anvil10has a recess10B on its rear end. The spindle shaft8B includes a protrusion on its front end. The recess10B on the rear end of the anvil10receives the protrusion on the front end of the spindle shaft8B.

The anvil10includes a rod-like anvil shaft10C and anvil projections10D. The tool hole10A is located in the front end of the anvil shaft10C. The tip tool90is attached to the anvil shaft10C. The anvil projections10D are located on the rear end of the anvil10. The anvil projections10D protrude radially outward from the rear end of the anvil shaft10C.

The anvil10is rotatably supported by anvil bearings46. The rotation axis of the anvil10, the rotation axis of the hammer47, and the rotation axis of the spindle8align with the rotation axis AX of the motor6. The anvil10rotates about the rotation axis AX. The anvil bearings46are located inward from the front cylinder4B. The anvil bearings46are held by the front cylinder4B in the hammer case4. The anvil bearings46support the anvil shaft10C. In the present embodiment, two anvil bearings46are arranged in the front-rear direction.

The hammer47includes hammer projections47B protruding frontward. The hammer projections47B can come in contact with the anvil projections10D. When the motor6operates with the hammer projections47B and the anvil projections10D in contact with each other, the anvil10rotates together with the hammer47and the spindle8.

The anvil10is strikable by the hammer47in the rotation direction. When, for example, the anvil10receives a higher load in a screwing operation, the anvil10may fail to rotate with power generated by the motor6alone. This stops rotation of the anvil10and the hammer47. The spindle8and the hammer47are movable relative to each other in the axial direction and in the circumferential direction with the balls48in between. When the hammer47stops rotating, the spindle8continues to rotate with power generated by the motor6. When the hammer47stops rotating and the spindle8rotates, the balls48move backward as being guided along the spindle groove8D and the hammer groove47A. The hammer47receives a force from the balls48to move backward with the balls48. In other words, the hammer47moves backward when the anvil10stops rotating and the spindle8rotates. Thus, the hammer projections47B and the anvil projections10D come out of contact with each other.

The coil spring49generates an elastic force for moving the hammer47forward. The hammer47that has moved backward then moves forward under the elastic force from the coil spring49. When moving forward, the hammer47receives a force in the rotation direction from the balls48. In other words, the hammer47moves forward while rotating. The hammer projections47B then come in contact with the anvil projections10D while rotating. Thus, the anvil projections10D are struck by the hammer projections47B in the rotation direction. The anvil10receives power from the motor6and an inertial force from the hammer47. The anvil10thus rotates at high torque about the rotation axis AX.

The tool holder11surrounds a front portion of the anvil10. The tool holder11holds the tip tool90received in the tool hole10A.

The fan12rotates with a rotational force from the motor6. The fan12is located rearward from the stator26in the motor6. The fan12generates an airflow for cooling the motor6. The fan12is fastened to at least a part of the rotor27. The fan12is fastened to the rear portion of the rotor shaft33with a bush12A. The fan12is between the rotor bearing39and the stator26. The fan12rotates as the rotor27rotates. As the rotor shaft33rotates, the fan12rotates together with the rotor shaft33. Air outside the housing2thus flows into the internal space of the housing2through the inlets19to cool the motor6. As the fan12rotates, the air passing through the internal space of the housing2flows out of the housing2through the outlets20.

The battery mount13is located in a lower portion of the battery holder23. A battery pack25is attached to the battery mount13in a detachable manner. The battery pack25serves as a power supply for the impact tool1. The battery pack25includes a secondary battery. The battery pack25in the present embodiment includes a rechargeable lithium-ion battery. The battery pack25is attached to the battery mount13to power the impact tool1. The motor6and the light unit18are each driven by power supplied from the battery pack25.

The trigger lever14is located on the grip22. The trigger lever14is operable by the operator to activate the motor6. The trigger lever14is operable to switch the motor6between the driving state and the stopped state.

The forward-reverse switch lever15is located above the grip22. The forward-reverse switch lever15is operable by the operator. The forward-reverse switch lever15is operable to switch the rotation direction of the motor6between forward and reverse. This switches the rotation direction of the spindle8.

The hand mode switch button16is located above the trigger lever14. The hand mode switch button16is operable by the operator. A circuit board16A and a switch16B are located behind the hand mode switch button16. The switch16B is mounted on the front surface of the circuit board16A. The hand mode switch button16is located in front of the switch16B. When the hand mode switch button16is pushed backward, the switch16B operates to cause the circuit board16A to output an operation signal. The operation signal output from the circuit board16A is transmitted to a controller (not shown). The controller changes the control mode of the motor6in response to the operation signal output from the circuit board16A.

Light Unit

FIG.5is a partial sectional view of the light unit18in the present embodiment.FIG.6is an exploded perspective view of the upper portion of the impact tool1as viewed from the front.FIG.7is a perspective view of the light unit18as viewed from the front.FIG.8is a perspective view of the light unit18as viewed from the rear.FIG.9is an exploded perspective view of the light unit18as viewed from the front.FIG.10is an exploded perspective view of the light unit18as viewed from the rear.

The light unit18emits illumination light. The light unit18illuminates the anvil10and an area around the anvil10with illumination light. The light unit18illuminates an area ahead of the anvil10with illumination light. The light unit18also illuminates the tip tool90attached to the anvil10and an area around the tip tool9) with illumination light.

The light unit18is located at the front of the hammer case4. The light unit18surrounds the front cylinder4B. The light unit18surrounds the anvil shaft10C with the front cylinder4B in between.

The COB LED50includes a substrate51, LED chips52being light emitters, banks54, and a phosphor55. The substrate51is, for example, an aluminum substrate, a glass fabric base epoxy resin substrate (flame retardant 4, or FR-4, substrate), or a composite base epoxy resin substrate (composite epoxy material 3, or CEM-3, substrate). The LED chips52are mounted on the front surface of the substrate51. The LED chips52are connected to the substrate51with gold wires (not shown). The gold wires interconnect the multiple LED chips52. The banks54are located on the front surface of the substrate51. The banks54surround the LED chips52. One bank54is located radially inward from the LED chips52, and the other bank54is located radially outward from the LED chips52. The banks54define a space for the phosphor55. The phosphor55covers the LED chips52between the banks54. A pair of electrodes (not shown) are located outside the banks54on the front surface of the substrate51. The electrodes may be located on the back surface of the substrate51. The pair of electrodes are a positive electrode and a negative electrode. Power output from the battery pack25is supplied to the electrodes. The power supplied to the electrodes is supplied to the LED chips52through the substrate51and the gold wires. The LED chips52emit light with power supplied from the battery pack25. The voltage of the battery pack25is decreased to 5 V by the controller (not shown) and applied to the LED chips52.

The light unit18includes the COB LED50, an optical member57, and a light shield60. The COB LED50includes the substrate51, the multiple LED chips52, the banks54, and the phosphor55.

The substrate51is annular. The substrate51surrounds the anvil shaft10C with the front cylinder4B in between. The substrate51includes a ring portion51A and a support51B. The support51B protrudes downward from a lower portion of the ring portion51A.

The LED chips52are located on the front surface of the ring portion51A in the substrate51. The LED chips52at least partially surround the anvil shaft10C with the front cylinder4B in between. The multiple (twelve in the present embodiment) LED chips52are arranged at equal intervals in the circumferential direction of the ring portion51A. The LED chips52are at angular positions of 0°, 30°, 60°, 90°, 120° 150°, 180°, 210°, 240°, 270°, 300°, and 330° about the rotation axis AX. The angular position of 0° is immediately above the rotation axis AX (anvil shaft10C). The angular position of 180° is immediately below the rotation axis AX (anvil shaft10C).

A resistor59is located between two adjacent LED chips52.

The banks54are located on the front surface of the ring portion51A in the substrate51. The banks54protrude frontward from the front surface of the ring portion51A. The banks54define the space for the phosphor55. The banks54are annular. The banks54in the present embodiment have a double annular structure. More specifically, the banks54in the present embodiment include a first bank54and a second bank54. The first bank54is annular and located on the front surface of the ring portion51A. The second bank54is annular and is located radially outward from the first bank54on the front surface of the ring portion51A. The first bank54is located radially inward from the LED chips52. The second bank54is located radially outward from the LED chips52. The LED chips52are between the first bank54and the second bank54.

The phosphor55is located on the front surface of the ring portion51A in the substrate51. The phosphor55is annular. The phosphor55covers the LED chips52between the first bank54and the second bank54.

A pair of lead wires58are connected to the substrate51. The lead wires58are connected to the electrodes described above. The pair of lead wires58are supported on the rear surface of the support51B. The lead wires58may be supported on the front surface of the support51B.

A current output from the battery pack25is supplied to the electrodes through the controller (not shown) and the lead wires58. The voltage of the battery pack25is decreased by the controller (not shown) and applied to the electrodes. The current supplied to the electrodes is supplied to the LED chip52through the substrate51and the gold wires. The LED chips52emit light with the current supplied from the battery pack25.

The optical member57is connected to the COB LED50. The optical member57is fixed to the substrate51. The optical member57is formed from a polycarbonate resin. The optical member57in the present embodiment is formed from a polycarbonate resin containing a white diffusion material. The optical member57is at least partially located frontward from the COB LED50. The optical member57includes an outer cylinder57A, an inner cylinder57B, a light transmitter57C, and a protrusion57D.

The outer cylinder57A is located radially outward from the inner cylinder57B. The outer cylinder57A is located radially outward from the LED chips52. The COB LED50is at least partially located between the outer cylinder57A and the inner cylinder57B in the radial direction. The outer cylinder57A is located radially outward from the ring portion51A in the substrate51. The inner cylinder57B is located radially inward from the ring portion51A in the substrate51. The inner cylinder57B is located radially inward from the LED chips52.

The light transmitter57C is annular. The light transmitter57C is located frontward from the LED chips52. The light transmitter57C connects the front end of the outer cylinder57A and the front end of the inner cylinder57B. The light transmitter57C faces the front surface of the ring portion51A. The light transmitter57C faces the LED chips52. Light emitted from the LED chips52passes through the light transmitter57C and illuminates an area ahead of the light unit18.

The light transmitter57C has an incident surface57E and an emission surface57F. Light from the LED chips52enters the incident surface57E. The light passing through the light transmitter57C is emitted through the emission surface57F. The front surface of the ring portion51A faces the incident surface57E of the light transmitter57C. The incident surface57E faces the LED chips52. The incident surface57E faces substantially rearward. The emission surface57F faces substantially frontward.

The protrusion57D protrudes downward from a lower portion of the outer cylinder57A. The protrusion57D defines an accommodation space inside. The support51B in the substrate51is received in the accommodation space inside the protrusion57D.

The light shield60is located radially outward from the outer cylinder57A in the optical member57. The light shield60has a lower light transmittance than the optical member57. Light emitted from the LED chips52may at least partially pass through the outer cylinder57A. The light shield60blocks light from the LED chips52emitted through the outer circumferential surface of the outer cylinder57A. The light shield60reduces the likelihood that light from the LED chips52emitted through the outer circumferential surface of the outer cylinder57A illuminates an area around the optical member57.

The light shield60is formed from a synthetic resin. The light shield60in the present embodiment is formed from a polycarbonate resin. The light shield60is formed from a polycarbonate resin containing a colored pigment. The colored pigment is, for example, a black pigment or a gray pigment. The light shield60in the present embodiment is formed from a polycarbonate resin containing a black pigment. The light shield60is black. The light shield60may be formed from a polycarbonate resin containing a gray pigment. The light shield60may be gray.

The light shield60includes a cylinder60A and a protrusion60B. The cylinder60A surrounds the outer cylinder57A. The cylinder60A covers the outer circumferential surface of the outer cylinder57A. The protrusion60B protrudes downward from a lower portion of the cylinder60A. The protrusion60B covers the outer surface of the protrusion57D. The protrusion60B covers the protrusion57D from below.

The light shield60is fixed to the optical member57. In the present embodiment, the optical member57and the light shield60are fixed together with a first adhesive70. The first adhesive70is between the outer circumferential surface of the outer cylinder57A and the inner circumferential surface of the cylinder60A.

The light shield60in the present embodiment has grooves60D and60E. The grooves60D and60E are recessed radially outward from the inner circumferential surface of the cylinder60A. The groove60D is located rearward from the groove60E. An abutment surface60C is located at the boundary between the grooves60D and60E in the front-rear direction. The abutment surface60C faces rearward. The abutment surface60C is annular. The optical member57has a facing surface57T facing the abutment surface60C. The optical member57has grooves57V and57W. The grooves57V and57W are recessed radially inward from the outer circumferential surface of the optical member57. The groove57V is located rearward from the groove57W. The facing surface57T is located at the boundary between the grooves57V and57W. The facing surface57T faces frontward. The abutment surface60C and the facing surface57T are in contact with each other. The first adhesive70fills the grooves60D and60E. The first adhesive70fills the grooves57V and57W. The first adhesive70is retained in a space between the groove60D and the groove57V and a space between the groove60E and the groove57W. The optical member57and the light shield60are fixed together with the first adhesive70filling the grooves57V and57W.

The light shield60includes a protrusion60G. The protrusion60G is located frontward from the grooves60D,60E,57V, and57W and protrudes radially inward from the inner circumferential surface of the cylinder60A. The protrusion60G has an inner end in the radial direction in contact with the outer circumferential surface of the optical member57. The protrusion60G surrounds the optical member57. The optical member57is fitted to the inner circumference of the protrusion60G.

The light shield60has a front end60F surrounding the emission surface57F of the light transmitter57C. The front end60F of the light shield60is located frontward from the front end of the light transmitter57C. The front end60F of the light shield60may be aligned with the front end of the light transmitter57C in the front-rear direction. In this structure, light is less likely to leak radially outward from the optical member57.

The light unit18including the COB LED50and the light shield60surrounds the anvil shaft10C in the anvil10. The light unit18surrounds the front cylinder4B in the hammer case4. The inner cylinder57B in the optical member57surrounds the front cylinder4B in the hammer case4. The inner cylinder57B in the optical member57is supported on the front cylinder4B in the hammer case4. The inner cylinder57B in the optical member57is fixed to the front cylinder4B in the hammer case4in a manner immovable in the axial direction.

The substrate51is between the outer cylinder57A and the inner cylinder57B in the radial direction. The substrate51is fixed to the optical member57. As shown inFIG.5, the substrate51and the optical member57are fixed together with a second adhesive75. The second adhesive75fixes the rear surface of the substrate51and the inner circumferential surface of the outer cylinder57A together. The second adhesive75may fix the rear surface of the substrate51and the outer circumferential surface of the inner cylinder57B together. The second adhesive75is light-shielding. The second adhesive75in the present embodiment is a black adhesive.

As shown inFIGS.5and6, the front cylinder4B includes multiple protrusions4D on its outer circumferential surface. The protrusions4D protrude radially outward from the outer circumferential surface of the front cylinder4B. The multiple (four in the present embodiment) protrusions4D are arranged at intervals in the circumferential direction. Each protrusion4D has a surface including a rear surface4E and a slope4F. The rear surface4E faces rearward. The slope4F slopes radially inward toward the front.

The light unit18is supported on the front cylinder4B in the hammer case4. The optical member57includes, on the inner circumference surface of the inner cylinder57B, rear slides57M and front slides57N. The rear slides57M and the front slides57N protrude radially inward from the inner circumferential surface of the inner cylinder57B. The front slides57N are located frontward from the rear slides57M. Four rear slides57M are arranged at intervals in the circumferential direction. The front slides57N are located in front of the four rear slides57M. A recess57K is between each rear slide57M and the corresponding front slide57N. The protrusions4D are received in the recesses57K. Each rear slide57M has a front surface57P in contact with the rear surface4E of the corresponding protrusion4D. Each front slide57N has a slope57Q facing the slope4F of the corresponding protrusion4D.

An insertion opening is between an end of each rear slide57M in a first circumferential direction and the corresponding front slide57N. The protrusions4D are received in the recesses57K through the insertion openings. The protrusions4D are placed through the insertion openings, and then the light unit18is rotated. This causes the protrusions4D to be received in the recesses57K. The optical member57and the front cylinder4B in the hammer case4are thus fixed together. This fixes the light unit18and the hammer case4together.

Light emitted from the LED chips52enters the incident surface57E through the phosphor55. As shown in, for example.FIG.5, the incident surface57E slopes radially inward toward the front. Light incident on the incident surface57E passes through the light transmitter57C and is emitted through the emission surface57F.

Light incident on the incident surface57E at least partially reaches the slopes57Q. The slopes57Q slope radially inward toward the front. Light reaching the slopes57Q is fully reflected from the slopes57Q, travels forward, and is emitted through the emission surface57F.

In the present embodiment, a sponge ring80is located behind the COB LED50. The sponge ring80has a rear surface supported on the annular portion4C in the hammer case4. The sponge ring80is at least partially compressed and in contact with the light unit18. In the example shown inFIG.5, the sponge ring80is in contact with the inner cylinder57B in the optical member57and the second adhesive75. The light unit18is supported on the compressed sponge ring80and is thus less likely to rattle relative to the hammer case4. The sponge ring80may support the inner cylinder57B.

Assembly Method

To assemble the light unit18, the light shield60is first attached to the optical member57. The optical member57is placed on a predetermined support surface with the emission surface57F facing upward. The first adhesive70is then applied to the outer circumferential surface of the optical member57including the facing surface57T. In the present embodiment, the first adhesive70is applied to the grooves57V and57W. The light shield60is then placed onto the optical member57from above the optical member57. The first adhesive70may be applied to the grooves60D and60E on the light shield60, and then the light shield60may be placed onto the optical member57.

When the light shield60is placed onto the optical member57, the abutment surface60C and the facing surface57T come in contact with each other. A front portion of the optical member57is fitted to the protrusion60G. The optical member57is lightly press-fitted to the inner circumference of the protrusion60G. This causes the first adhesive70to wet and spread in the grooves57V and57W. The first adhesive70applied to the grooves57V and57W is less likely to move upward, and thus does not reach the emission surface57F when the light shield60is placed onto the optical member57. The inner end of the protrusion60G in the radial direction coming in contact with the outer circumferential surface of the optical member57also prevents the first adhesive70applied to the grooves57V and57W from reaching the emission surface57F. The first adhesive70may at least partially flow between a rear end portion (lower end portion) of the outer cylinder57A in the optical member57and a rear end portion of the inner circumferential surface of the light shield60, but does not flow to the emission surface57F. The first adhesive70is thus less likely to stain the emission surface57F. The first adhesive70does not adhere to the emission surface57F and is thus less likely to block light to be emitted through the emission surface57F. The substrate51and the optical member57are fixed together with the second adhesive75.

Once the optical member57, the light shield60, and the COB LED50are fixed together with the first adhesive70and the second adhesive75, the light unit18and the hammer case4are fixed together. As described above, the protrusions4D are placed through the insertion openings between the ends of the rear slides57M in the first circumferential direction and the corresponding front slides57N, and then the light unit18is rotated. This causes the protrusions4D to be received in the recesses57K. This fixes the light unit18and the hammer case4together. The light unit18is at least partially in contact with the sponge ring80supported on the annular portion4C and is thus less likely to rattle relative to the hammer case4. With the inner cylinder57B in the optical member57fixed to the front cylinder4B in the hammer case4, the light unit18is fixed to the hammer case4in the axial direction alone. The hammer case4and the protrusion60B on the light shield60are then held between the left housing2L and the right housing2R. This fixes the hammer case4and the light unit18to the housing2in the rotation direction. The left housing2L and the right housing2R are then fastened together with the screws2S.

Method of Use

The operator operates the trigger lever14to activate the motor6and cause the LED chips52in the COB LED50to emit light. The COB LED50emits light with high luminance and brightly illuminates a workpiece.

When light emitted from the LED chips52at least partially passes through the outer cylinder57A, such light emitted through the outer circumferential surface of the outer cylinder57A may reach the eyes of the operator and cause glare to the operator. This may lower the visibility of a workpiece by the operator. In the present embodiment, the light shield60reduces glare to the operator.

As described above, the impact tool1according to the present embodiment includes the motor6, the anvil10as an output unit, the LED chips52, the optical member57, and the light shield60. The anvil10operates with a rotational force from the motor6. The LED chips52at least partially surround the anvil10. The optical member57includes the outer cylinder57A and the light transmitter57C. The outer cylinder57A is located radially outward from the LED chips52. The light transmitter57C is located frontward from the LED chips52. The light transmitter57C allows light emitted from the light emitter52to pass through. The light shield60is located radially outward from the outer cylinder57A.

In the above structure, when light emitted from the LED chips52at least partially passes through the outer cylinder57A, the light shield60located radially outward from the outer cylinder57A reduces the likelihood that such light passing through the outer cylinder57A reaches the eyes of the operator. This reduces glare to the operator. This structure can thus avoid lowering the visibility of a workpiece by the operator.

The light shield60in the present embodiment has a lower light transmittance than the optical member57.

When light emitted from the LED chips52at least partially passes through the outer cylinder57A, the light shield60with a lower light transmittance reduces the likelihood that such light passing through the outer cylinder57A reaches the eyes of the operator.

The light shield60in the present embodiment is formed from a synthetic resin.

The light shield60is thus less likely to break than a light shield60formed from, for example, glass.

The light shield60in the present embodiment is formed from a polycarbonate resin containing a colored pigment.

The light shield60thus has high strength and is light-shielding.

The light shield60in the present embodiment is black.

The light shield60is thus highly light-shielding.

The impact tool1according to the present embodiment includes the first adhesive70fixing the optical member57and the light shield60together.

The optical member57and the light shield60are thus fixed together with the first adhesive70.

The first adhesive70in the present embodiment is between the outer circumferential surface of the outer cylinder57A and the inner circumferential surface of the light shield60.

The first adhesive70is thus less likely to be exposed on the outer circumferential surface of the light shield60.

The optical member57in the present embodiment has the grooves57V and57W recessed radially inward from the outer circumferential surface of the optical member57. The grooves57V and57W receive the first adhesive70.

Thus, an appropriate amount of the first adhesive70is placed in the grooves57V and57W.

The light shield60in the present embodiment includes the protrusion60G located frontward from the grooves57V and57W. The protrusion60G protrudes radially inward from the inner circumferential surface of the light shield60.

The protrusion60G prevents the first adhesive70from flowing out. The first adhesive70is thus less likely to overflow to the front end of the light shield60or to the front end of the optical member57. For example, the first adhesive70is applied to the grooves57V and57W on the optical member57, and the light shield60is then attached to the outer circumference of the optical member57. This reduces overflowing of the first adhesive70.

The protrusion60G in the present embodiment has the inner end in contact with the optical member57.

This effectively reduces the likelihood that the first adhesive70leaks to the front end of the light shield60or to the front end of the optical member57.

The protrusion60G in the present embodiment surrounds the optical member57. The optical member57is fitted to the protrusion60G.

The optical member57is fitted to the protrusion60G and is thus fixed to the light shield60. The optical member57in the present embodiment is lightly press-fitted to the protrusion60G.

The light shield60in the present embodiment has the front end60F surrounding the emission surface57F of the light transmitter57C.

The light shield60does not block light emitted through the emission surface57F of the light transmitter57C, thus allowing a workpiece to be illuminated appropriately.

In the present embodiment, the light shield60has the front end60F aligned with or located frontward from the front end of the light transmitter57C in the front-rear direction.

The light shield60thus sufficiently covers the outer circumferential surface of the optical member57.

The impact tool1according to the present embodiment includes the substrate51surrounding the anvil10and including the ring portion51A. The LED chips52are located on the front surface of the ring portion51A.

The substrate51and the LED chips52are included in the COB LED50. A workpiece is thus illuminated with light with high luminance.

The impact tool1according to the present embodiment includes the second adhesive75fixing the substrate51and the optical member57together.

The COB LED50and the optical member57are thus fixed together with the second adhesive75.

The second adhesive75in the present embodiment fixes the rear surface of the substrate51and the inner circumferential surface of the outer cylinder57A together.

This reduces the likelihood of the LED chips52being covered with the second adhesive75.

The second adhesive75in the present embodiment is light-shielding.

Light emitted from the LED chips52is thus less likely to leak from the rear of the substrate51to an area around the impact tool1. For example, with the case cover5being transparent, light from the LED chips52leaking rearward from the substrate51is blocked by the second adhesive75and is thus less likely to leak through the case cover5to the area around the impact tool1.

The impact tool1according to the present embodiment includes the phosphor55covering the LED chips52.

The phosphor55increases the luminance of light emitted from the LED chips52. The phosphor55also protects the LED chips52.

The optical member57in the present embodiment includes the inner cylinder57B located radially inward from the ring portion51A. The light transmitter57C connects the front end of the outer cylinder57A and the front end of the inner cylinder57B.

The outer cylinder57A in the optical member57is located radially outward from the ring portion51A, and the inner cylinder57B in the optical member57is located radially inward from the ring portion51A, thus stabilizing the connection between the substrate51and the optical member57.

Other Embodiments

In the above embodiment, the light shield60is formed from a polycarbonate resin containing a colored pigment. The light shield60may include a black coating applied on the surface of its polycarbonate resin member. The light shield60may be formed from rubber, an elastomer, or a metal.

In the above embodiment, the impact tool1is an impact driver. The impact tool1may be an impact wrench.

In the above embodiment, the electric work machine1is an impact tool as an example of a power tool. The power tool is not limited to an impact tool. Examples of the power tool include a driver drill, an angle drill, a screwdriver, a hammer, a hammer drill, a circular saw, and a reciprocating saw.

The electric work machine1may not be a power tool.FIG.11is a perspective view of an electric work machine100according to another embodiment as viewed from the front. The electric work machine100shown inFIG.11is an air duster. The electric work machine100includes a housing200, a battery mount130, a trigger switch140, an output unit1000, and a light unit18. The housing200includes a motor compartment210, a grip220, and a battery holder230. The grip220extends downward from a lower portion of the motor compartment210. The battery holder230connects to a lower portion of the grip220. The motor compartment210accommodates a motor and a fan (not shown inFIG.11). The trigger switch140is located on the grip220. The battery mount130is located in a lower portion of the battery holder230. The battery mount130receives a battery pack25. The output unit1000operates with a rotational force from the motor. The output unit1000is located frontward from the front end of the motor compartment210. When the motor rotates, the fan rotates, thus jetting air from a jet opening1000A in the output unit1000. The light unit18described in the above embodiment may surround the output unit1000in the electric work machine100.

In the above embodiment, the electric work machine (denoted with, for example, 1) may use utility power (alternating current power supply) in place of the battery pack25.

REFERENCE SIGNS LIST