Working machine
Patent Information
- Application Number
- JP2025524048
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Filing Date
- 2025-11-27
- Publication Date
- 2026-03-04
Abstract
Description
Work equipment
[0001] The present invention relates to a work machine such as a driving machine.
[0002] One example of a work machine is a driving tool that has a driver blade that strikes a fastener, a coil spring that can expand and contract in the vertical direction, and a plunger that engages with the driver blade and can move in the vertical direction due to the biasing force of the coil spring.
[0003] As an example of such a fastener driving machine, Patent Document 1 discloses a fastener driving machine that includes an ejection section that positions a fastener to be struck by a driver blade, and a magazine that can accommodate multiple fasteners and feeds the fasteners toward the ejection section.
[0004] Japanese Patent Application Laid-Open No. 2022-107504
[0005] In the driving machine described in the above-mentioned Patent Document 1, when a nail (fastener) is placed in the ejection section, there is a possibility that the nail may become jammed in the ejection section.
[0006] When a nail gets stuck in the ejector, it often happens that the nail gets caught between the ejector and the plunger, which is biased by the coil spring. In this case, removing the nail from the ejector is difficult because the plunger is under load due to the bias of the coil spring.
[0007] As a result, there is a risk that the efficiency of the nail driving tool will decrease due to nail jamming, and the convenience of the nail driving tool may be reduced.
[0008] An object of the present invention is to provide a work machine with improved convenience.
[0009] The working machine of the present invention includes a motor, an ejection unit that supports a fastener so as to be ejectable, a striking unit that is movable in a first direction and a second direction opposite to the first direction and that can strike the fastener supported by the ejection unit by moving in the first direction, a biasing unit that biases the striking unit in the first direction, a control unit that controls whether to drive or stop the motor, and a rotating unit that rotates in a third direction when the motor is driven, and the striking unit is engaged with the rotating unit so that the rotating unit rotates in the third direction. The motor moves from the first position to the second position in the second direction against the biasing force of the biasing part, and when the engagement with the rotating part is released at the second position, the motor moves in the first direction from the second position to the third position by the biasing force of the biasing part, striking the stopper, thereby performing an impact operation.The control unit supplies power of a first power value to the motor when the impact operation is performed, and when it detects a malfunction of the impact part, supplies power of a second power value smaller than the first power value to the motor.
[0010] According to the present invention, the convenience of the work machine can be improved.
[0011] 1 is a right side view showing the internal structure of a working machine according to an embodiment of the present invention. FIG. 2 is a view showing the structure of a main part of the working machine shown in FIG. 1 at a standby position, where (a) is a left side view and (b) is a view seen from an arrow A in (a). FIG. 3 is a view showing the structure of a main part of the working machine shown in FIG. 1 at top dead center, where (a) is a left side view and (b) is a view seen from an arrow A in (a). FIG. 4 is a view showing the structure of a main part of the working machine shown in FIG. 1 at bottom dead center during normal operation, where (a) is a left side view and (b) is a view seen from an arrow A in (a). FIG. 5 is a time chart showing the relationship between time and displacement of a main part of the working machine according to an embodiment of the present invention during normal operation. FIG. 6 is a view showing the structure of a main part of the working machine shown in FIG. 1 when a nail jam occurs, where (a) is a left side view and (b) is a view seen from an arrow A in (a). FIG. 7 is a view showing the structure of a main part of the working machine shown in FIG. 1 when a nail jam occurs, where (a) is a left side view and (b) is a view seen from an arrow A in (a). 1A and 1B are diagrams showing the structure of the main parts of the working machine shown in Fig. 1 at the time of re-engagement after the nail jam has been released, where (a) is a left side view and (b) is a view as seen from the arrow A in (a). Fig. 1B is a time chart showing the relationship between time and displacement in the main parts of the working machine of the embodiment of the present invention at the time of the occurrence of a nail jam. Fig. 1C is a flowchart showing motor control in the impact operation of the working machine of the embodiment of the present invention.
[0012] A working machine according to an embodiment of the present invention will be described with reference to the drawings. In Figures 1 to 4 and 6 to 8, a first direction B1 is defined as a downward direction, and a second direction B2 opposite to the first direction B1 is defined as an upward direction.
[0013] The working machine of this embodiment is for striking fasteners, and will be described by taking a driving machine 10 that strikes and drives fasteners such as nails 22, for example. The working machine may also be a nail gun. FIG. 1 is a diagram showing the internal structure of the driving machine 10 of one embodiment. The driving machine 10 includes a housing 11. The housing 11 includes a main body 12, a motor case 14, a handle 15, and an attachment portion 16.
[0014] The main body 12 has a cylindrical shape extending in the up-down direction M1. The motor case 14 has a tubular shape extending rearward from the main body 12 in the front-to-rear direction N1. The handle 15 also has a tubular shape extending rearward from the main body 12. The handle 15 is located above the motor case 14. The mounting portion 16 connects the rear end of the motor case 14 and the rear end of the handle 15.
[0015] The main body 12 houses a winding gear 35, a plunger 40, a driver blade 41, a spring (biasing member) 45, a counterweight 50, and the like, which will be described later with reference to FIG.
[0016] An ejection unit 13 that supports nails (fasteners) 22 so that they can be ejected is provided below the main body 12. A magazine 19 that can hold a plurality of nails 22 is attached below the motor case 14. The nails 22 held by the magazine 19 are sent out to the ejection unit 13 one by one.
[0017] A push lever 20 is supported below the main body 12. The push lever 20 is an example of an operating part, and is activated when it comes into contact with a target material into which a nail 22 is driven. The lower end of the push lever 20 is located below the injection part 13. When the lower end of the push lever 20 comes into contact with the target material, the push lever 20 moves in the second direction B2 and is activated (ON), and when the lower end of the push lever 20 moves away from the target material (contact is released), the push lever 20 moves in the first direction B1 due to the biasing force and is released (OFF). Note that, hereinafter, the contact of the lower end of the push lever 20 with the target material will be abbreviated as "the push lever 20 comes into contact with the target material."
[0018] A trigger 21 is supported on the handle 15. The trigger 21 is also an example of an operating unit. The trigger 21 is activated by being operated by an operator. Specifically, when the trigger 21 is pulled by the finger of the operator holding the handle 15, the trigger 21 moves in the second direction B2 and is activated (ON), and when the trigger 21 is no longer pulled by the finger, the trigger 21 moves in the first direction B1 due to a biasing force and is deactivated (OFF).
[0019] Therefore, the push lever 20 and the trigger 21 are an example of an operating portion, and are operated by an operator.
[0020] The motor case 14 houses a motor 25 and a gearbox 30. The motor 25 has a rotor and a stator. When power is supplied, the rotor rotates, causing a motor shaft attached to the rotor to rotate. The motor 25 is, for example, a brushed motor. The gearbox 30 has an input element, a planetary gear mechanism, and an output element. The input element is connected to the motor shaft of the motor 25 and rotates integrally with the motor shaft of the motor 25. The output element is connected to a first rotating shaft 36a of a first gear 36 (see FIG. 2) and rotates integrally therewith. The first gear 36 is part of the winding gear 35. The driving force generated by the rotation of the motor shaft is transmitted to the input element, reduced in speed by the planetary gear mechanism, and transmitted to the output element and then to the first gear 36. The motor 25, the gearbox 30, and the first gear 36 are coaxially arranged from rear to front.
[0021] A battery pack 17 is attached to the attachment portion 16 to supply power to the motor 25. The battery pack 17 is a DC power supply. The battery pack 17 has a plurality of battery cells, and the battery cells may be lithium-ion batteries, nickel-metal hydride batteries, lithium-ion polymer batteries, nickel-cadmium batteries, or the like.
[0022] A controller 18 is disposed inside the mounting portion 16. The controller 18 is an example of a control portion, and controls the driving or stopping of the motor 25.
[0023] 2 is a diagram showing the main parts of the driving tool 10. The main parts of the driving tool 10 are housed in the main body 12, and include a winding gear 35, a plunger 40, a driver blade 41, a spring 45, and a counterweight 50.
[0024] As shown in FIG. 2, the winding gear 35 is an example of a rotating part, and is a gear that rotates in a third direction B3 when the motor 25 is driven, and can rotate in a fourth direction B4 opposite to the third direction B3 when the motor 25 is stopped.
[0025] The winding gear 35 includes three gears: a first gear 36 located in the lower stage, a second gear 37 located in the middle stage, and a third gear 38 located in the upper stage. The first gear 36 is rotatably supported by a first rotating shaft 36a, the second gear 37 is rotatably supported by a second rotating shaft 37a, and the third gear 38 is rotatably supported by a third rotating shaft 38a. The first rotating shaft 36a, the second rotating shaft 37a, and the third rotating shaft 38a are attached to a holding plate 39 (see FIG. 1) that extends in the up-down direction M1.
[0026] The first gear 36 meshes with the second gear 37, and the second gear 37 meshes with the third gear 38. Therefore, as shown in FIG. 2, when the first gear 36 rotates counterclockwise, the second gear 37 rotates clockwise and the third gear 38 rotates counterclockwise. The rotation direction of the winding gear 35 in this case is defined as the "third direction B3." On the other hand, when the first gear 36 rotates clockwise, the second gear 37 rotates counterclockwise and the third gear 38 rotates clockwise. The rotation direction of the winding gear 35 in this case is defined as the "fourth direction B4."
[0027] 2, a first cam roller 36b, which is eccentric with respect to the first rotation shaft 36a, is provided on the front surface of the first gear 36. A second cam roller 37b and a third cam roller 37c, which are eccentric with respect to the second rotation shaft 37a, are provided on the front surface of the second gear 37. A fourth cam roller 38b and a fifth cam roller 38c, which are eccentric with respect to the third rotation shaft 38a, are provided on the front surface of the third gear 38. Each cam roller is capable of rotating on its own axis while revolving around its respective rotation shaft.
[0028] 1, a top holder 48 is fixed to the upper part of the main body 12, and a bottom holder 49 is fixed to the lower part. A guide bar 47 is provided between the top holder 48 and the bottom holder 49. The upper end of the guide bar 47 is fixed to the top holder 48, and the lower end of the guide bar 47 is fixed to the bottom holder 49.
[0029] As shown in Figure 2(b), there are two guide bars 47, one on the left and one on the right. A guide shaft 46 is provided between the two guide bars 47. The upper end of the guide shaft 46 is fixed to a top holder 48, and the lower end of the guide shaft 46 is fixed to a bottom holder 49. The plunger 40 and a counterweight 50 are disposed between the two guide bars 47. The counterweight 50 is located above the plunger 40.
[0030] The plunger 40 is movable in a first direction B1 and a second direction B2 along a guide shaft 46 and a guide bar 47. A driver blade 41 is fixed to the plunger 40. The driver blade 41 is movable together with the plunger 40 in the first direction B1 and the second direction B2. The lower end of the driver blade 41 protrudes from the main body 12 shown in FIG. 1 , and can strike the nail 22 supported by the ejection unit 13 by moving in the first direction B1. The plunger 40 and the driver blade 41 are an example of a striking unit 55.
[0031] The counterweight 50 reduces the recoil when the striking portion 55 strikes the nail 22. The counterweight 50 is movable in a first direction B1 and a second direction B2 along the guide shaft 46 and the guide bar 47. The counterweight 50 is a member that moves in conjunction with the striking portion 55, and moves in the opposite direction to the plunger 40. Specifically, when the plunger 40 moves in the second direction B2, the counterweight 50 moves in the first direction B1, and when the plunger 40 moves in the first direction B1, the counterweight 50 moves in the second direction B2.
[0032] A spring 45 is provided between the plunger 40 and the counterweight 50. The upper end of the spring 45 is fixed to the counterweight 50, and the lower end of the spring 45 is fixed to the plunger 40. The spring 45 is, for example, a compression coil spring. The spring 45 is an example of a biasing portion, and biases the plunger 40 in the first direction B1 and biases the counterweight 50 in the second direction B2.
[0033] A lower bumper 44 is provided between the bottom holder 49 and the plunger 40. The lower bumper 44 absorbs part of the kinetic energy of the plunger 40 moving in the first direction B1 due to the biasing force of the spring 45, thereby preventing damage to the plunger 40. The lower bumper 44 is fixed to the upper surface of the bottom holder 49.
[0034] An upper bumper 52 is provided between the top holder 48 and the counterweight 50. The upper bumper 52 absorbs part of the kinetic energy of the counterweight 50 moving in the second direction B2 due to the biasing force of the spring 45, thereby preventing damage to the counterweight 50. The upper bumper 52 is fixed to the underside of the top holder 48.
[0035] The guide shaft 46 is inserted through the lower bumper 44 , the plunger 40 , the spring 45 , the counterweight 50 , and the upper bumper 52 .
[0036] A first rack 42 and a second rack 43 are fixed to the plunger 40. A first cam roller 36b provided on the first gear 36 is engageable with the first rack 42. A second cam roller 37b and a third cam roller 37c provided on the second gear 37 are engageable with the second rack 43. The first cam roller 36b, the second cam roller 37b, and the third cam roller 37c are examples of engaging portions, and are engageable with the plunger 40 via the first rack 42 or the second rack 43. The engaging portions rotate in the third direction B3 (i.e., the first gear 36 counterclockwise and the second gear 37 clockwise) about the first rotation shaft 36a or the second rotation shaft 37a while engaged with the plunger 40, thereby moving the plunger 40 in the second direction B2.
[0037] A third rack 51 is fixed to the counterweight 50. A fourth cam roller 38b and a fifth cam roller 38c provided on the third gear 38 are engageable with the third rack 51. The fourth cam roller 38b and the fifth cam roller 38c rotate in the third direction B3 (i.e., the third gear 38 rotates counterclockwise) about the third rotation shaft 38a while engaged with the counterweight 50 via the third rack 51, thereby moving the counterweight 50 in the first direction B1.
[0038] A latch 53 is attached to the left guide bar 47 shown in Figure 2(b). The latch 53 is rotatable around a support shaft 54 relative to the guide bar 47. The support shaft 54 is located within the range of the third gear 38 in the up-down direction M1. The latch 53 is biased clockwise by a torsion coil spring.
[0039] The latch 53 has a hook 53a and an arm 53b. The hook 53a and the arm 53b are arranged in the longitudinal direction of the latch 53, separated by the support shaft 54. The hook 53a is located between the top holder 48 and the support shaft 54 in the vertical direction M1. The hook 53a is capable of engaging with and disengaging from an engaging pin 50a provided on the counterweight 50. The arm 53b is located between the bottom holder 49 and the support shaft 54 in the vertical direction M1. The arm 53b is capable of contacting and separating from the plunger 40.
[0040] As shown in FIG. 1 , a top dead center switch 60 is provided at the top of the main body 12. The top dead center switch 60 is a detector that detects the position of the counterweight 50. Because the counterweight 50 and the striking unit 55 are both wound up by the winding gear 35 and operate in tandem, the top dead center switch 60 can indirectly detect the position of the striking unit 55 based on the detection of the position of the counterweight 50. Specifically, when the counterweight 50 is at the top dead center (the lower end of the counterweight 50's vertical movement range), the top dead center switch 60 comes into contact with a protrusion 50 b on the counterweight 50, turning on and sending an on signal to the controller 18. When the counterweight 50 is at the top dead center, the plunger 40 is located at a predetermined position (fourth position) between the top dead center and bottom dead center. In other words, the controller 18 detects that the plunger 40 is located at the predetermined position (fourth position) by detecting the on signal sent from the top dead center switch 60.
[0041] 2 shows the plunger 40 in a state where it is in a plunger standby position (first position), while Fig. 3 shows the plunger 40 in a state where it is in a plunger top dead center (second position), and Fig. 4 shows the plunger 40 in a state where it is in a plunger bottom dead center (third position).
[0042] The striking unit 55, which includes the plunger 40 and the driver blade 41, is engaged with the winding gear 35 and rotates in the third direction B3, causing the striking unit 55 to move in the second direction B2 against the biasing force of the spring 45 from the plunger standby position (first position) in Fig. 2 to the plunger top dead center (second position) in Fig. 3. Furthermore, when the striking unit 55 is disengaged from the winding gear 35 at the plunger top dead center (second position) in Fig. 3, the striking unit 55 is moved in the first direction B1 by the biasing force of the spring 45 from the plunger top dead center (second position) in Fig. 3 to the plunger bottom dead center (third position) in Fig. 4, thereby striking the nail 22.
[0043] In the driving tool 10 of this embodiment, the controller 18 supplies power of a first power value to the motor 25 when the impact unit 55 is performing a normal impact operation. On the other hand, when the controller 18 detects a malfunction of the impact unit 55, it controls the motor 25 to supply power of a second power value that is smaller than the first power value.
[0044] 2(a), the plurality of nails 22 stored in the magazine 19 shown in Fig. 1 are connected with an adhesive, and this is called the nail connecting body 23. That is, the impacting portion 55 moves downward due to the biasing force of the spring 45, and the impacting portion 55 strikes one nail 22 located at the extreme end of the nail connecting body 23. The struck nail 22 peels off and separates from the nail connecting body 23 and is driven into the mating material.
[0045] 2 to 5, an example of a normal impact operation of the impact unit 55 will be described. In this embodiment, a case will be described in which the plunger 40 is kept waiting at a position between the bottom dead center and the top dead center in order to shorten the time from when the motor 25 is driven until the plunger 40 reaches the top dead center.
[0046] FIG. 2 is a diagram showing a state in which the plunger 40 is disposed at the plunger standby position (first position) (time t0 in FIG. 5 ). That is, in the state shown in FIG. 2 , the plunger 40 and the counterweight 50 are disposed at their respective standby positions as shown in FIG. 5 . At this time, as shown in FIG. 2( b ), the second rack 43 of the plunger 40 is engaged with the third cam roller 37 c of the second gear 37, and further, the third rack 51 of the counterweight 50 is engaged with the fifth cam roller 38 c of the third gear 38. Furthermore, when the plunger 40 is disposed at the plunger standby position (first position), the top dead center switch 60 is in the ON state as shown in FIG. 5 .
[0047] When the plunger 40 is in the standby state shown in FIG. 2 , the switches of the trigger 21 and the push lever 20 shown in FIG. 1 are turned ON, and a predetermined first power value is supplied from the battery pack 17 to the motor 25, causing the motor 25 to rotate. As the motor 25 rotates, the winding gear 35 rotates in the third direction B3 (i.e., the first gear 36 rotates counterclockwise, the second gear 37 rotates clockwise, and the third gear 38 rotates counterclockwise). At this time, as shown in FIG. 5 , the power of the predetermined first power value (motor current) supplied to the motor 25 is at a duty of 100%. At this time, the load of the spring 45 continues to increase, and the motor load torque also increases. The plunger 40 is pushed up by the third cam roller 37c of the second gear 37 and begins to move from the plunger standby position in the second direction B2 (upward). Meanwhile, the counterweight 50 starts to move in the first direction B1 (downward) from the counterweight standby position.
[0048] 2 (time t0 in FIG. 5), when the winding gear 35 rotates in the third direction B3, the third cam roller 37c of the second gear 37, which is engaged with the second rack 43 of the plunger 40, revolves, causing the plunger 40 to move in the second direction B2 (upward) against the biasing force of the spring 45. Also, the fifth cam roller 38c of the third gear 38, which is engaged with the third rack 51 of the counterweight 50, revolves, causing the counterweight 50 to move in the first direction B1 (downward) against the biasing force of the spring 45.
[0049] Furthermore, as the plunger 40, which is in contact with the arm 53b, continues to move in the second direction B2 (upward), the latch 53 further rotates counterclockwise around the support shaft 54 against the biasing force of the spring 45. As a result, the hook 53a engages with the engagement pin 50a, causing the counterweight 50 to reach the counterweight bottom dead center, and the movement of the counterweight 50 in the first direction B1 (downward) is stopped (time t1 in FIG. 5).
[0050] Even after the movement of the counterweight 50 in the first direction B1 is stopped, the motor 25 continues to rotate, and the plunger 40 continues to move in the second direction B2 (upward). Note that the motor load torque shown in Fig. 5 reaches a maximum at time t1 because the movement of the counterweight 50 in the first direction B1 is stopped at time t1, and then begins to decrease due to the influence of the component force.
[0051] Next, as shown in FIG. 3 , the rotation of the winding gear 35 in the third direction B3 causes the plunger 40 to reach the plunger top dead center (second position) (time t2 in FIG. 5 ). When the plunger 40 reaches the plunger top dead center (second position), the spring load reaches its maximum. Then, as shown in FIG. 3( b), the rotation of the winding gear 35 rotates the second gear 37, which disengages the third cam roller 37c of the second gear 37 from the second rack 43 of the plunger 40. The plunger 40 is then released in the first direction B1 (downward). That is, when the plunger 40 is released, the impact portion 55, including the plunger 40, is forcefully released in the first direction B1 (downward) by the biasing force of the spring 45. This gradually reduces the spring load, and the motor load torque becomes zero.
[0052] When the impact portion 55 is released, as shown in Figure 5, the plunger 40 moves toward the plunger bottom dead center, and the counterweight 50 also moves in the second direction B2 (upward) slightly after the impact portion 55 is released (time t3 in Figure 5).
[0053] Thereafter, the plunger 40, which moves vigorously in the first direction B1 due to the biasing force of the spring 45, and the driver blade 41 fixed to the plunger 40 strike the nail 22 supported by the ejection part 13 in Fig. 1 at the plunger bottom dead center (third position) shown in Fig. 4, driving it into the mating material (time t4 in Fig. 5). At this time, as shown in Fig. 4(a), the driver blade 41 strikes one nail 22 located at the endmost part of the nail connecting body 23. The nail 22 struck by the driver blade 41 peels off and separates from the nail connecting body 23, and is driven into the mating material.
[0054] After the driver blade 41 drives the nail 22, the plunger 40 collides with the lower bumper 44 and reaches the plunger bottom dead center (third position). At this time, the lower bumper 44 absorbs part of the kinetic energy of the plunger 40. Then, as shown in FIG. 4B, the first rack 42 of the plunger 40 engages with the first cam roller 36b of the first gear 36. As shown in FIG. 5, the spring load becomes 0 (zero) at the plunger 40 bottom dead center.
[0055] When the plunger 40 reaches the bottom dead center (third position), the top dead center switch 60 is switched OFF.
[0056] On the other hand, the counterweight 50 reaches the counterweight top dead center (time t5 in FIG. 5) with a slight delay after the plunger 40 reaches the plunger bottom dead center (third position).
[0057] In the driving tool 10 of this embodiment, when the plunger 40 reaches the plunger bottom dead center (third position) (time t4 in FIG. 5 ), the controller 18 determines whether the top dead center switch 60 has switched from ON to OFF within a predetermined time (threshold time) from the start of the motor 25. For example, the predetermined time (threshold time) from the start of the motor is set to 135 msec, and the controller 18 determines whether the top dead center switch 60 has switched from ON to OFF within this predetermined time. In other words, based on the detection result of the top dead center switch 60, the controller 18 determines whether the operation of the striking unit 55 is causing a malfunction such as a nail jam.
[0058] If the top dead center switch 60 switches from ON to OFF within the above-mentioned predetermined time, the controller 18 determines that no malfunction such as nail jamming has occurred, and continues to supply power at 100% duty as motor current.
[0059] As an example, if the top dead center switch 60 switches from ON to OFF 110 msec after the motor is started, the controller 18 determines that a nail jam has not occurred because the top dead center switch 60 switched from ON to OFF within a predetermined time (135 msec), and continues to supply power at 100% duty. However, if the top dead center switch 60 does not switch from ON to OFF within the predetermined time after the motor is started, the controller 18 determines that a nail jam has occurred, and reduces the power supply to the motor to a duty rate lower than 100% to control the motor 25 to rotate at a slower speed than normal. Control of the motor 25 when a nail jam occurs will be described in detail below in the section on operation when a nail jam occurs.
[0060] As described above, when the controller 18 determines that no malfunction such as nail jamming has occurred, it continues to supply power to the motor at a duty of 100%.
[0061] Subsequently, as shown in FIG. 4, with the plunger 40 at its bottom dead center and the counterweight 50 at its top dead center, the windup gear 35 further rotates in the third direction B3.
[0062] Then, due to the revolution of the first cam roller 36b engaged with the first rack 42, the plunger 40 begins to move in the second direction B2 (upward) against the biasing force of the spring 45 (time t6 in FIG. 5). As a result, the spring load and motor load torque begin to increase. Also, slightly after the plunger 40 starts to move in the second direction B2 (upward), the counterweight 50 starts to move in the first direction B1 (downward) from the counterweight top dead center (time t7 in FIG. 5).
[0063] As the counterweight 50 continues to move in the first direction B1 (downward) from the counterweight top dead center, at time t8 in Figure 5, the counterweight 50 switches the top dead center switch 60 from OFF to ON. Then, slightly after the top dead center switch 60 switches from OFF to ON, the motor is stopped (time t9 in Figure 5).
[0064] After the motor is de-energized, the plunger 40 is pushed up in the second direction B2 (upward) by inertia (in the range P1 in FIG. 5 ) and reaches the standby position (first position) of the plunger 40 shown in FIG. 2 (time t10 in FIG. 5 ). At this time, the counterweight 50 also reaches the weight standby position.
[0065] Next, an example of the operation of the striking unit 55 when a nail jam occurs (when the striking unit 55 malfunctions) will be described with reference to Figures 6 to 10. Here, as with the above, a case will be described in which the plunger 40 is kept waiting at a position between the plunger bottom dead center and the plunger top dead center. Note that the operation of the striking unit 55 from when the plunger 40 moves from the plunger waiting position to the plunger top dead center until it is released at the top dead center is the same as the operation shown in Figures 2 and 3.
[0066] That is, in the state shown in Fig. 2, the plunger 40 and the counterweight 50 are each disposed in a standby position as shown in Fig. 9. At this time, as shown in Fig. 2(b), the second rack 43 of the plunger 40 and the third cam roller 37c of the second gear 37 are engaged, and further, the third rack 51 of the counterweight 50 and the fifth cam roller 38c of the third gear 38 are engaged. Furthermore, when the plunger 40 is disposed in the plunger standby position (first position), the top dead center switch 60 is in an ON state as shown in Fig. 5.
[0067] When the trigger switch 61 and push lever switch 62 shown in FIG. 1 are turned ON and a predetermined first power value is supplied from the battery pack 17 to the motor 25 while the plunger 40 is in the standby state shown in FIG. 2 , the motor 25 rotates (step S1 “Start” in FIG. 10 ). As the motor 25 rotates, the winding gear 35 rotates in the third direction B3 (i.e., the first gear 36 rotates counterclockwise, the second gear 37 rotates clockwise, and the third gear 38 rotates counterclockwise). At this time, as shown in FIG. 9 , the power (motor current) of the predetermined first power value supplied to the motor 25 is at a duty of 100%. The load of the spring 45 continues to increase, and the motor load torque also increases. The plunger 40 is pushed up by the third cam roller 37c of the second gear 37 and begins to move in the second direction B2 (upward) from the plunger standby position. Meanwhile, the counterweight 50 starts to move in the first direction B1 (downward) from the counterweight standby position.
[0068] 2 (time t0 in FIG. 9 ), when the winding gear 35 rotates in the third direction B3, the third cam roller 37c of the second gear 37, which is engaged with the second rack 43 of the plunger 40, revolves, causing the plunger 40 to move in the second direction B2 (upward) against the biasing force of the spring 45. Also, the fifth cam roller 38c of the third gear 38, which is engaged with the third rack 51 of the counterweight 50, revolves, causing the counterweight 50 to move in the first direction B1 (downward) against the biasing force of the spring 45.
[0069] Furthermore, as the plunger 40, which is in contact with the arm 53b, continues to move in the second direction B2 (upward), the latch 53 further rotates counterclockwise around the support shaft 54 against the biasing force of the spring 45. As a result, the hook 53a engages with the engagement pin 50a, causing the counterweight 50 to reach the counterweight bottom dead center, and the movement of the counterweight 50 in the first direction B1 (downward) is stopped (time t11 in FIG. 9 ).
[0070] Even after the movement of the counterweight 50 in the first direction B1 is stopped, the motor 25 continues to rotate, and the movement of the plunger 40 in the second direction B2 (upward) continues. Note that the motor load torque shown in Fig. 9 reaches a maximum at time t11 because the movement of the counterweight 50 in the first direction B1 is stopped at time t11, and then continues to decrease due to the influence of the component force.
[0071] Next, as shown in FIG. 3 , the rotation of the winding gear 35 in the third direction B3 causes the plunger 40 to reach the plunger top dead center (second position) (time t12 in FIG. 9 ). When the plunger 40 reaches the plunger top dead center (second position), the spring load reaches its maximum. Then, as shown in FIG. 3( b), the rotation of the winding gear 35 rotates the second gear 37, which disengages the third cam roller 37c of the second gear 37 from the second rack 43 of the plunger 40. The plunger 40 is then released in the first direction B1 (downward). That is, when the plunger 40 is released, the impact portion 55, including the plunger 40, is forcefully released in the first direction B1 (downward) by the biasing force of the spring 45. This gradually reduces the spring load, and the motor load torque becomes zero.
[0072] When the striking portion 55 is released, the plunger 40 moves toward the plunger bottom dead center, as shown in Figure 9. At this time, the counterweight 50 remains at the counterweight bottom dead center because the engagement between the protrusion 50b and the latch 53 is not released.
[0073] Thereafter, as shown in FIG. 9 , the controller 18 determines whether a malfunction such as nail jamming has occurred during a predetermined time tX1. That is, the "detection of top dead center switch switching" of step S2 in FIG. 10 is executed. Here, the controller 18 determines whether the top dead center switch 60 has switched from ON to OFF after a predetermined time tX1 has elapsed (within the threshold time) since the motor was energized. For example, the predetermined time (threshold time) tX1 from the start of the motor is set to 135 msec, and the controller 18 determines whether the top dead center switch 60 has switched from ON to OFF within this predetermined time. In other words, based on the detection result of the top dead center switch 60, the controller 18 determines whether the operation of the striking unit 55 is causing a malfunction such as nail jamming.
[0074] If the top dead center switch 60 is switched from ON to OFF within the above-mentioned predetermined time (YES), the controller 18 determines that no malfunction such as nail jamming has occurred, and continues to supply power to the motor at 100% duty.
[0075] As an example, if the top dead center switch 60 switches from ON to OFF 110 msec after the motor is started (YES), the controller 18 determines that no nail jamming has occurred because the top dead center switch 60 switched from ON to OFF within the predetermined time, and continues to supply power at 100% duty. That is, the "normal winding operation" of step S3 in FIG. 10 is executed. Specifically, after the striking part 55 is released, the controller 18 determines that no nail jamming has occurred, and the driver blade 41 drives the nail 22, while the plunger 40 reaches the plunger bottom dead center. The plunger 40 is then wound up by the winding gear 35, and power is stopped after a threshold time has elapsed, but inertia causes it to reach the plunger standby position ("return" of step S4 in FIG. 10).
[0076] On the other hand, if a nail jam occurs after the striking part 55 is released as shown in FIG. 6 (time tX2 in FIG. 9), the plunger 40 stops at a position between the plunger top dead center and the plunger bottom dead center. At this time, the counterweight 50 is not launched because the latch 53 remains disengaged. If the top dead center switch 60 does not switch from ON to OFF within the predetermined time (e.g., 135 msec) after the motor is started, i.e., if the determination in step S2 of FIG. 10 "Detection of Top Dead Center Switch Switching" is NO, the controller 18 determines that a malfunction such as a nail jam has occurred. In other words, if the top dead center switch 60 does not detect the position of the striking part 55 within the predetermined time after the motor 25 is driven, the controller 18 determines that a malfunction such as a nail jam has occurred in the striking part 55. In other words, if the top dead center switch 60 does not detect the position of the impact portion 55 within the above-mentioned specified time after driving the motor 25, the controller 18 determines that the engagement between the impact portion 55 and the winding gear 35 has been released and that the impact portion 55 is stopped above the bottom dead center of the plunger.
[0077] Next, if the controller 18 determines that the operation of the striking unit 55 is causing a malfunction, it brakes the rotation of the motor 25 (step S5 "BRAKE" in FIG. 10). Here, the motor power supply is reduced to a duty ratio less than 100%, causing the motor 25 to rotate at a slower speed than normal (time t13 in FIG. 9). For example, the motor power supply is reduced to a duty ratio of approximately 20%, and the motor 25 is driven for a predetermined time while braking. That is, the motor power supply is reduced to a duty ratio of approximately 20%, causing the motor 25 to rotate at a low speed for a predetermined time while braking (range P2 in FIG. 9). The predetermined time is, for example, approximately one second (step S6 "DRIVE FOR A PRECISE TIME AT DUTY THRESHOLD %" in FIG. 10).
[0078] By reducing the duty of the power supply to the motor to about 20% and rotating the motor 25 at a low speed, the winding gear 35 continues to rotate, but after the point at which a nail jam occurs, as shown in Figure 7, the winding gear 35 does not engage with the plunger 40 or the counterweight 50, so the winding gear 35 continues to rotate idly (time tX3 in Figure 9). At this time, because the winding gear 35 does not engage with the plunger 40 or the counterweight 50, the motor load torque is also 0 (zero) (range P3 in Figure 9). In other words, because the winding gear 35 does not engage with the plunger 40 or the counterweight 50, the motor load torque becomes 0 (zero), and the motor 25 can continue to rotate.
[0079] Subsequently, as the winding gear 35 continues to rotate (idle) in the third direction B3, the winding gear 35 and the plunger 40 re-engage as shown in FIG. 8 (time t14 in FIG. 9 ). Specifically, the second rack 43 of the plunger 40 re-engages with the third cam roller 37c of the second gear 37. However, the torque output from the motor 25 at this time is smaller than the normal winding torque. In other words, if the power supplied to the motor 25 at 100% duty is defined as a first power value and the power supplied to the motor 25 at 20% duty is defined as a second power value, the torque output by the motor 25 at the second power value is smaller than the torque required to move the striking part 55 in the second direction B2 (upward). As a result, the motor 25 continues to rotate at a low speed with a moderately small output torque. Therefore, the plunger 40 remains stopped at a position between the bottom dead center and the top dead center without being wound up or descending. In other words, the controller 18 drives the motor 25 so that the winding gear 35 engages with the plunger 40, and then stops the motor 25 without moving the plunger 40 upward, thereby restricting the plunger 40 from moving downward.
[0080] Next, the "stop" of the motor 25 is executed as shown in step S7 of Fig. 10. Specifically, the controller 18 supplies power of the second power value at a duty of about 20% to the motor 25 for a predetermined time, and then stops the supply of power to the motor 25. Next, an "error display" is displayed as shown in step S8, and "power off" is executed as shown in step S9. Thereafter, the nail 22 causing the nail jam is removed. At this time, the second rack 43 of the plunger 40 is engaged with the third cam roller 37c of the second gear 37, so the plunger 40 does not fall.
[0081] The driving tool 10 may also include a restricting unit that restricts rotation of the take-up gear 35 in a fourth direction B4, which is opposite to the third direction B3 shown in FIG. 2. An example of such a restricting unit is the gearbox 30 and the first rotating shaft 36a. In this case, the restricting unit stops rotation of the first gear 36 in the fourth direction B4 before the plunger 40 reaches bottom dead center. The gearbox 30 rotatably supports the first gear 36 and also serves as a support unit that stops rotation of the first gear 36 by friction between the gearbox 30 and the first rotating shaft 36a.
[0082] By providing the above-mentioned restricting unit, there is no need to control the motor 25 to stop the rotation of the first gear 36 in the fourth direction B4. There is also no need to provide a brake to stop the rotation of the first gear 36. Furthermore, because the winding gear 35 is configured to be rotatable in the fourth direction B4, which is opposite to the third direction B3, there is no need to provide a one-way clutch to restrict the reverse rotation of the winding gear 35. As a result, it is possible to prevent the driving tool 10 from becoming larger and heavier due to an increase in the number of parts, and to improve the operability of the driving tool 10. However, as another example of the restricting unit, a one-way clutch that prevents the first gear 36 from rotating in the fourth direction B4 may be provided in the gear box 30.
[0083] Furthermore, in the driving tool 10, the winding gear 35 switches between a first state in which it can engage with the striking portion 55 and a second state in which it cannot engage with the striking portion 55 depending on its rotational position, and can switch from the first state to the second state multiple times during one rotation of the winding gear 35. Specifically, the first state is a state in which the winding gear 35 can engage with the striking portion 55 while the striking portion 55 moves from the plunger top dead center (second position) to the plunger bottom dead center (third position) after release, and is a state in which no operational malfunction such as nail jamming has occurred.
[0084] On the other hand, the second state is a state in which the winding gear 35 cannot engage with the striking portion 55 after release while the striking portion 55 moves from the plunger top dead center (second position) to the plunger bottom dead center (third position), resulting in an operational malfunction such as a nail jam. In other words, in the nail driver 10 in which the winding gear 35 is rotated by the drive of the motor 25 and the rotation of the winding gear 35 winds up the plunger 40, the winding gear 35 can switch between the first state and the second state after the striking portion 55 is released, depending on the rotational position of the winding gear 35. During one rotation of the winding gear 35, the winding gear 35 can switch from the first state to the second state multiple times.
[0085] According to the nail driver 10 of this embodiment, even when a nail jam occurs, the winding gear 35 and the plunger 40 re-engage, thereby preventing the winding gear 35, which is the rotating part, from disengaging from the plunger 40, which is the striking part 55. Specifically, when the nail driver 10 detects a nail jam, the duty of the power supplied to the motor 25 is reduced to less than 100%, braking the motor 25 and controlling the motor 25 to rotate at a low speed. When a nail jam occurs, the winding gear 35 and the plunger 40 disengage and the motor load becomes 0 (zero), so the motor 25 rotates at a low speed and the winding gear 35 also continues to rotate (idle). As a result, the winding gear 35 and the plunger 40 re-engage.
[0086] For example, when a nail jam occurs, depending on the timing at which the winding gear 35 stops, the plunger 40 may stop at an intermediate position where it does not engage with the winding gear 35. However, in the nail driver 10 of this embodiment, when a nail jam is detected, the duty of the power supplied to the motor 25 is reduced to less than 100%, so that the motor 25 rotates at a low speed. This causes the winding gear 35 to rotate (idle) while rotating the motor 25 at a low speed, and the winding gear 35 and the plunger 40 can be re-engaged.
[0087] At this time, the motor 25 continues to rotate at a low speed with a moderately small output torque, so that the plunger 40 can be maintained stopped at a position between the plunger bottom dead center and the plunger top dead center without being wound up or descending.
[0088] Therefore, even when the urging force of the spring 45 is applied to the plunger 40, the plunger 40 can be prevented from falling. As a result, the nail 22 caught in the ejection part 13 can be easily removed.
[0089] This reduces the risk of a decrease in the workability of the driving work using the driving machine 10, and improves the convenience of the driving machine 10.
[0090] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit and scope of the present invention. For example, in the above-described embodiment, the controller 18 determines whether the striking unit 55 is malfunctioning, such as due to a nail jam, based on the threshold time for detecting whether the top dead center switch 60 is switched. In this case, for example, if the battery is depleted and the voltage drops, the top dead center switch 60 may switch after the set predetermined time has elapsed, even if a nail jam has not occurred. Therefore, instead of setting a fixed predetermined time as the threshold time, the threshold time may be changed in accordance with changes in the battery voltage.
[0091] 10... driving machine (work machine), 11... housing, 12... main body, 13... injection unit, 14... motor case, 15... handle, 16... mounting unit, 17... battery pack, 18... controller (control unit), 19... magazine, 20... push lever, 21... trigger, 22... nail (fastener), 23... nail connecting body, 25... motor, 30... gear box, 35... winding gear (rotating unit), 36... first gear, 36a... first rotating shaft, 36b... first cam roller, 37... second gear, 37a... second rotating shaft, 37b... second cam roller, 37c... third cam roller, 38... third gear, 38a... third rotating shaft, 38b... fourth cam roller, 38c... fifth cam roller, 39... retaining plate, 40... plunger, 41... driver blade, 4 2...First rack, 43...Second rack, 44...Lower bumper, 45...Spring, 46...Guide shaft, 47...Guide bar, 48...Top holder, 49...Bottom holder, 50...Counterweight, 50a...Engagement pin, 50b...Convex portion, 51...Third rack, 52...Upper bumper, 53...Latch, 53a...Hook, 53b...Arm, 54...Support shaft, 55 ...impact section, 60...top dead center switch (detection section), B1...first direction, B2...second direction, B3...third direction, B4...fourth direction, M1...up and down direction, N1...front and back direction, P1, P2, P3...range, t0, t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13, t14...time, tX1...predetermined time, tX2, tX3...time
Claims
1. A motor; an ejection section that supports the fastener so that the fastener can be ejected; a striking portion that is movable in a first direction and a second direction opposite to the first direction and that strikes the stopper supported by the ejection portion by moving in the first direction; a biasing portion that biases the striking portion in the first direction; a control unit that controls driving or stopping the motor; a rotating portion that rotates in a third direction when the motor is driven; a detection unit capable of detecting the position of the hitting unit, The hitting part is When the rotating portion rotates in the third direction while being engaged with the rotating portion, the rotating portion moves in the second direction against the biasing force of the biasing portion from the first position to the second position, When the engagement with the rotating portion is released at the second position, the biasing force of the biasing portion moves the stopper from the second position to the third position in the first direction, striking the stopper, and then the stopper is re-engaged with the rotating portion to move to the first position and stop, thereby performing a striking operation. The control unit supplies power of a first power value to the motor when the impact operation is performed, and when it detects a malfunction in which the impact part stops at a position other than the first position, supplies power of a second power value to the motor that is small enough that the rotating part cannot move the impact part.
2. The work machine according to claim 1 , wherein a torque value of the motor output by the electric power of the second electric power value is smaller than a torque value of the motor required to move the impact part in the second direction.
3. The work machine according to claim 2 , wherein the control unit stops the supply of power to the motor after supplying power at the second power value for a predetermined time.
4. The work machine according to claim 1 , further comprising a restricting portion that restricts the rotation of the rotating portion in a fourth direction opposite to the third direction.
5. 5. The work machine according to claim 3 or 4, wherein the rotating unit switches between a first state in which the striking unit can engage with the striking unit while the striking unit moves from the second position to the third position and a second state in which the striking unit cannot engage with the striking unit while the striking unit moves from the second position to the third position, depending on the rotational position of the rotating unit, and the rotating unit switches from the first state to the second state multiple times during one rotation of the rotating unit.
6. The detection unit is capable of detecting that the striking unit is located at a fourth position between the first position and the second position, The work machine according to claim 1 , wherein the control unit determines whether or not the impact unit is malfunctioning based on the detection result of the detection unit.
7. 7. The work machine according to claim 6, wherein if the detection unit does not detect that the impact unit is located at the fourth position within a predetermined time after driving the motor, the control unit determines that the impact unit is malfunctioning.
8. The impact device further includes a counterweight that moves in conjunction with the impact portion, The work machine according to claim 6, wherein the detection unit detects the position of the counterweight, and detects the position of the impact unit based on the detection of the position of the counterweight.
9. A motor; an ejection section that supports the fastener so that the fastener can be ejected; a striking portion that is movable in a first direction and a second direction opposite to the first direction and that strikes the stopper supported by the ejection portion by moving in the first direction; a biasing portion that biases the striking portion in the first direction; a control unit that controls driving or stopping the motor; a rotating portion that rotates in a third direction when the motor is driven; a detection unit capable of detecting the position of the hitting unit, The hitting part is When the rotating portion rotates in the third direction while being engaged with the rotating portion, the rotating portion moves in the second direction against the biasing force of the biasing portion to a top dead center, When the engagement with the rotating portion is released, the biasing force of the biasing portion moves the stopper in the first direction to the bottom dead center and strikes the stopper, and then the stopper re-engages with the rotating portion, moving to the first position and stopping there; When the control unit detects a malfunction in which the impact part stops at a position other than the first position while the impact part is disengaged from the rotating part, the rotating part receives a torque from the motor that is smaller than the torque value required to move the impact part in the second direction, and stops the impact part without moving it in the second direction while engaged with the impact part, thereby restricting the movement of the impact part in the first direction.
10. The work machine described in claim 9, wherein when the control unit detects that the impact portion has stopped on the second direction side of the bottom dead center while disengaged from the rotating portion, it drives the motor to a torque value that is smaller than the torque value of the motor required to move the impact portion in the second direction.