WO2018062293A1 - Work machine - Google Patents

Abstract

A work machine has an output shaft to which a tip tool can be attached and which is driven to rotate by a predetermined drive power source, a cover for covering at least a part of an outer periphery of the tip tool attached to the output shaft, a detector that detects that the work machine is bounced off of a workpiece by a reaction force applied from the workpiece to the tip tool, and a cover moving mechanism that moves the cover to a protective position covering the outer periphery of the tip tool when the detector detects that the work machine is bounced off.

Description

Working machine Cross-reference of related applications

This international application claims priority based on Japanese Patent Application No. 2016-189968 filed with the Japan Patent Office on September 28, 2016, and is based on Japanese Patent Application No. 2016-189968. The entire contents are incorporated herein by reference.

The present disclosure relates to a work machine capable of cutting a workpiece with a tip tool attached to an output shaft.

For example, in a work machine such as a grinder that can cut a workpiece by rotating a cutting tool (cutting blade) for cutting, when the tip tool is rotated and brought into contact with the workpiece, A reaction force is applied to the tip tool, and the work machine may be rebounded from the workpiece.

When such rebounding (hereinafter also referred to as kickback) occurs, the work implement moves against the user's intention, and if the tip tool rotates, the workpiece and surrounding members will be damaged. Sometimes.

Therefore, in this type of work machine, it has been proposed to detect the occurrence of kickback and stop the driving of the motor (see, for example, Patent Document 1).

Japanese Patent Publication No. 64-6898

However, even if the occurrence of kickback is detected and the driving of the motor is stopped as in the proposed device, it takes time for the motor to actually stop. For this reason, it is conceivable that the tip tool hits the workpiece or a surrounding member after the kickback has occurred and before the motor stops, and is damaged by the rotation of the tip tool.

Also, with the proposed apparatus, even if the motor can be stopped suddenly after the kickback has occurred, the tip tool cannot be prevented from hitting the workpiece or surrounding members. Therefore, in this case, it is conceivable that the tip tool whose rotation has been stopped after the kickback has occurred hits the surrounding member and damages the surrounding member. In addition, the tip tool itself may be damaged.

In one aspect of the present disclosure, in a work machine capable of cutting a workpiece by rotating the tip tool, the tip tool is prevented from hitting surrounding members when rebounded by a reaction force applied from the workpiece during cutting. It is desirable to be able to do so.

In the working machine according to one aspect of the present disclosure, a tip tool for cutting a workpiece can be attached, an output shaft that is rotationally driven by a predetermined driving force source, and an outer periphery of the tip tool attached to the output shaft A cover for covering at least a part of the cover.

Also, the work machine is provided with a detection unit that detects that the work machine is rebounded from the work material (ie, kickback) by a reaction force applied to the tip tool from the work material. When the detection unit detects kickback, the cover moving mechanism closes the cover and moves the cover to a protection position that covers the outer periphery of the tip tool.

Therefore, according to the working machine of the present disclosure, when a kickback occurs during the work of cutting the workpiece, the cover is moved to the protection position that covers the outer periphery of the tip tool in a wider range and is covered with the cover. It is possible to suppress the outer peripheral portion of the tip tool from hitting surrounding members.

For this reason, it can suppress that a tip tool hits a surrounding member with generation | occurrence | production of a kickback, a surrounding member is damaged, or a tip tool itself is damaged.
Here, the cover moving mechanism includes an urging member that urges the cover toward the protection position, and a movable portion that engages the cover to position the cover at a retracted position away from the protection position. Also good.

In this case, when the detection unit detects that the work machine is rebounded from the workpiece (that is, kickback), the movable unit releases the engagement with the cover and applies the biasing member. You may be comprised so that a cover may be moved to a protection position with force.

On the other hand, the cover moving mechanism engages with the rotating member and moves the cover to the protection position when the detection unit detects that the work implement is rebounded from the workpiece (that is, kickback). It may be configured.

In this case, the cover moving mechanism may include an electromagnetic clutch that moves the cover to the protection position by energizing the rotating member by energization, and a control unit that controls energization of the electromagnetic clutch.

When the kickback is detected by the detection unit, if the control unit energizes the electromagnetic clutch to engage the cover with the rotating member, the cover is attached to the rotating member via the electromagnetic clutch. Engagement can move the cover to the protected position.

The rotating member may be any member that is rotated by a predetermined driving force source. For example, an output shaft to which the tip tool is attached may be used as the rotating member.
The cover moving mechanism may be configured to move the cover to the protection position by frictionally engaging the cover with the rotating member.

In this way, after moving the cover to the protection position, it is not necessary to stop the rotating member in order to position the cover at the protection position, so that the configuration of the cover moving mechanism can be simplified.

It is sectional drawing showing the structure of the marunoco of 1st Embodiment. It is a side view showing the state which saw the saw saw shown in FIG. 1 from the left direction. It is a block diagram showing the structure of the whole drive system of a motor. It is a flowchart showing the cover closing control process performed in a control part. It is sectional drawing showing the structure around the spindle of the grinder of 2nd Embodiment. It is a top view showing the state which looked at the wheel cover of the grinder from the gear housing side. It is a top view showing the state which closed the auxiliary cover in the wheel cover of FIG. It is a block diagram showing the structure of the movable part provided in the wheel cover.

DESCRIPTION OF SYMBOLS 1 ... Marunouchi, 2 ... Motor, 4 ... Rotating shaft, 8 ... Handle part, 10 ... Main body case, 12 ... Gear mechanism, 14 ... Output shaft, 16 ... Saw blade, 20 ... Saw blade case, 24 ... Support member, 26 DESCRIPTION OF SYMBOLS ... Cover, 27 ... Mounting part, 28, 82 ... Energizing member, 30 ... Electromagnetic clutch, 32 ... Coil, 36 ... Gutter, 38 ... Ring member, 39 ... Plate, 40 ... Operation switch, 42 ... Switch detection circuit, 46, 87 ... rectifying / smoothing circuit, 48, 88 ... DC / DC converter, 50 ... circuit board, 52, 96 ... driving circuit, 54 ... control circuit, 56 ... acceleration sensor, 58 ... transmitter, 60 ... grinder, 61 ... Motor housing 62 ... Gear housing 64 ... Spindle 70 ... Tip tool 72 ... Wheel cover 78 ... Movable part 80 ... Auxiliary cover 84 ... Generator 86 ... Roller 90 ... Acti Eta, 92 ... receiving unit, 94 ... determining unit.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
[First Embodiment]
As shown in FIGS. 1 and 2, the working machine 1 of this embodiment includes a body case 10 in which a motor 2 as a driving force source is housed, and a gear that transmits the rotation of the motor 2 to a saw blade 16. The mechanism 12 is housed, and a saw blade case 20 formed so as to cover a part of the saw blade 16 is provided.

The main body case 10 is provided with a handle portion 8 for a user to hold so as to protrude in a direction perpendicular to the rotating shaft 4 of the motor 2.
The rotating shaft 4 of the motor 2 is rotatably fixed by a bearing provided in the saw blade case 20 on the side opposite to the saw blade case 20 of the main body case 10. Note that a fan 6 that generates cooling air by rotation is provided on the rotating shaft of the motor 2.

On the opposite side of the saw blade case 20 from the main body case 10, an output shaft 14 for fixing the disk-shaped saw blade 16 is fixed via a bearing 23 and a support member 24.
The saw blade 16 is sandwiched between annular gripping members 19A and 19B formed so that the position facing the center of the plate surface of the saw blade 16 is hollow, and abuts against a flange 36 provided around the tip of the output shaft 14. As a result, the output shaft 14 is disposed at the end opposite to the main body case 10.

Further, the saw blade 16 passes the bolt 18 through the hollow portions of the clamping members 19A and 19B, and the bolt 18 is screwed into a screw hole provided at the tip of the output shaft 14 to be tightened. It is fixed.

The support member 24 is attached to the saw blade case 20 so that the center axis of the output shaft 14 is parallel to the center axis of the rotation shaft 4 of the motor 2 while the output shaft 14 is rotatably supported via the bearing 23. It is fixed.

In the saw blade case 20, the output shaft 14 and the rotating shaft 4 of the motor 2 are connected via a reduction gear mechanism 12. For this reason, the output shaft 14 is rotationally driven by the motor 2 and rotates the saw blade 16.

The saw blade case 20 is formed so as to cover substantially half of the outer periphery of the saw blade 16 fixed to the output shaft 14, and the outer periphery of the support member 24 that supports the output shaft 14 is provided on the outer periphery of the saw blade 16. A cover 26 for covering the remaining part is provided.

The cover 26 is fixed to the outer periphery of the support member 24 so as to be rotatable around the output shaft 14 through an attachment portion 27 formed in an annular shape so as to surround the outer periphery of the support member 24. The cover 26 is formed so as to be able to cover substantially the entire outer periphery of the saw blade 16 released from the saw blade case 20 by rotating around the output shaft 14.

The attachment part 27 of the cover 26 is urged by an urging member 28 formed of a coil spring in a direction covering the outer periphery of the saw blade 16 (direction of arrow A shown in FIG. 2). For this reason, the cover 26 is normally held at a protective position that covers substantially the entire outer periphery of the saw blade 16 by the urging force of the urging member 28, and is rotated against the urging force of the urging member 28. The outer periphery of the saw blade 16 can be exposed.

Then, when the cover 26 is opened and the outer periphery of the saw blade 16 is exposed as described above, the workpiece can be cut by rotating the saw blade 16 and contacting the workpiece. The cover 26 is movable from the protection position to a retracted position that exposes substantially the entire outer periphery of the saw blade 16 protruding from the saw blade case 20.

Further, the saw blade case 20 is provided with a plate-like base 22 for contacting the upper surface of the workpiece to be cut. The base 22 is a member for adjusting the protruding amount of the saw blade 16 from the contact surface with the workpiece (in other words, the cutting depth of the workpiece).

Next, a bobbin 34 around which a coil 32 constituting the electromagnetic clutch 30 is wound is provided at the outer peripheral portion of the output shaft 14 between the flange 36 and the support member 24. Is provided with an annular member 38 that forms a magnetic path by energizing the coil 32.

The annular member 38 is connected to the mounting portion 27 of the cover 26 via the plate 39. When the coil 32 is energized, the annular member 38 has a magnetic path from the mounting portion 27 of the cover 26 to the flange portion 36 via the plate 39. The hook portion 36 and the attachment portion 27 of the cover 26 are engaged with each other.

That is, when the output shaft 14 is rotating in the direction of cutting the workpiece, when the coil 32 is energized, the electromagnetic clutch 30 engages the output shaft 14 and the cover 26, and the output shaft 14. The cover 26 can be moved to the protected position by the rotation of.

Further, since the flange portion 36 and the attachment portion 27 of the cover 26 are frictionally engaged by the magnetic force generated by energization of the coil 32, when the cover 26 moves to the protection position when the output shaft 14 rotates, The rotation of the output shaft 14 can be suppressed by the frictional force.

Next, the configuration of the drive system that drives the motor 2 in the marnoco 1 of the present embodiment will be described.
As shown in FIG. 2, the handle portion 8 is provided with an operation switch (so-called trigger switch) 40 for a user to operate with a finger while holding the handle portion 8. Further, the handle portion 8 includes a rectifying / smoothing circuit 46 that generates a DC voltage for driving the motor by rectifying and smoothing an AC voltage input from the power cord 44 via the fuse 45 (see FIG. 3). Is provided.

As shown in FIG. 3, an operation switch 40 is provided in the output path of the DC voltage from the rectifying and smoothing circuit 46. When the operation switch 40 is operated and turned on, the DC voltage is applied to the drive circuit 52 of the motor 2. Is supplied.

The drive circuit 52 is a full bridge provided with switching elements for connecting the terminals of each phase of the motor 2 (three-phase motor in the figure) to the positive side and the negative side of the power supply path from the rectifying and smoothing circuit 46, respectively. A circuit (so-called inverter circuit) is used.

The drive circuit 52 is mounted on the circuit board 50 together with a switch detection circuit 42 that detects the operation amount of the operation switch 40 and a control circuit 54 that controls the drive of the motor 2 via the drive circuit 52. In addition, this circuit board 50 is being fixed to the internal space of the connection part to the main body case 10 of the saw blade case 20, as shown in FIG.

The circuit board 50 includes a DC / DC converter 48 that generates a power supply voltage (DC constant voltage) Vcc for driving the control circuit 54 from a DC voltage generated by the rectifying and smoothing circuit 46, and an acceleration sensor 56. Has also been implemented.

When the acceleration sensor 56 comes into contact with the workpiece while the saw blade 16 is rotated to cut the workpiece, the marnoco 1 is rebounded from the workpiece by the reaction force received from the workpiece. This is a sensor for detecting this, and corresponds to the detection unit of the present disclosure.

For this reason, the acceleration sensor 56 rebounds from the workpiece of the marlinoko 1, for example, in a direction opposite to the contact surface of the base 22 with the workpiece about the output shaft 14 (upward in FIGS. 1 and 2). ) Is provided on the circuit board 50 so as to detect acceleration. A detection signal from the acceleration sensor 56 is also input to the control circuit 54.

The acceleration sensor 56 is not a sensor that detects acceleration in one axis direction, but a sensor that detects acceleration in two or three axes perpendicular to each other, and rebounds from the workpiece (in other words, , Kickback) may be detected.

The control circuit 54 corresponds to a control unit of the present disclosure, and is configured by a microcontroller (MCU: Micro Control Unit) including a CPU, a ROM, a RAM, and the like.
When the operation of the operation switch 40 is detected by the switch detection circuit 42, the control circuit 54 sets an energization current to the motor 2 according to the operation amount, and energizes the motor 2 via the drive circuit 52. Control the current.

As a result, the motor 2 and the saw blade 16 attached to the output shaft 14 rotate at a rotation speed corresponding to the operation amount of the operation switch 40 by the user.
Further, as one of the main routines, the control circuit 54 repeatedly performs the cover closing control shown in FIG. 4 separately from the drive control of the motor 2 as described above.

This cover closing control process detects that kickback has occurred when the motor 2 is driven (in other words, when the workpiece is cut), and energizes the coil 32 of the electromagnetic clutch 30 to place the cover 26 in the protected position. It is processing for moving to.

As shown in FIG. 4, in this cover closing control process, the control circuit 54 first determines whether or not the operation switch 40 is in an on state in S110 (S represents a step). If the operation switch 40 is not in the ON state, the drive of the motor 2 is stopped, and kickback does not occur. Therefore, the cover closing control process is temporarily ended.

If it is determined in S110 that the operation switch 40 is in the ON state, the control circuit 54 proceeds to S120, reads the acceleration from the acceleration sensor 56 as the detection unit, and in S130, the read acceleration is It is determined whether or not a threshold value set in advance for kickback determination has been exceeded. If the acceleration does not exceed the threshold value, the control circuit 54 determines that no kickback has occurred, and once ends the cover closing control process.

On the other hand, if the acceleration exceeds the threshold value, the control circuit 54 determines that kickback has occurred, and proceeds to S140, and energizes the coil 32 of the electromagnetic clutch 30 so that the cover 26 is attached to the output shaft 14. Rotation of the forcibly and instantaneously moves to the protected position.

Next, in S150, it is determined whether or not the operation switch 40 has been turned off to wait for the user to stop operating the operation switch 40. In S150, if it is determined that the operation switch 40 is in the on state, the process proceeds to S140, and energization of the coil 32 of the electromagnetic clutch 30 is continued to hold the cover 26 in the protected position.

Further, when it is determined in S150 that the operation switch 40 has been turned off, the drive of the motor 2 is stopped by the drive control of the motor 2, and thus the coil 32 of the electromagnetic clutch 30 is energized. Stop and temporarily close the cover closing control process.

As described above, in the Marunoco 1 of the present embodiment, when the control circuit 54 detects that a kickback has occurred from the acceleration detected by the acceleration sensor 56 during driving of the motor 2, the control circuit 54 applies to the coil 32 of the electromagnetic clutch 30. Is moved to the protected position.

For this reason, when the cutting operation of the workpiece is performed, when the saw 1 is rebounded from the workpiece, the cover 26 is closed to the protection position, and the saw blade 16 that is the tip tool of the saw 1 hits the surrounding members. The surrounding members can be damaged and the saw blade 16 can be prevented from being damaged.

Further, the marvel 1 of the present embodiment includes a biasing member 28 as a biasing member that biases the cover 26 in the closing direction. For this reason, when kickback occurs, the cover 26 can be moved to the protected position by the urging force of the urging member 28 without using the electromagnetic clutch 30.

However, the urging force of the urging member 28 may not move the cover 26 to the protection position instantaneously.
On the other hand, in the marnoco 1 of the present embodiment, when the kickback occurs, the cover 26 and the output shaft 14 are engaged by energizing the electromagnetic clutch 30, so that the cover 26 can be moved more securely to the protection position. Can do. For this reason, when the kickback occurs, the saw blade 16 can be covered with the cover 26, and the saw blade 16 can be prevented from directly hitting surrounding members.
[Second Embodiment]
As shown in FIG. 5, a grinder 60 that is a working machine of the present embodiment includes a motor housing 61 that houses a motor that is a driving force source, a gear housing 62, and a wheel cover 72.

The motor housing 61 is a substantially cylindrical housing and houses a motor. The motor is accommodated in the motor housing 61 so that the rotation axis thereof is coincident with or parallel to the central axis of the motor housing 61, and the tip of the rotation axis of the motor protrudes toward the gear housing 62.

A rear cover is provided on the opposite side of the motor housing 61 from the gear housing 62. A power cord is pulled out from the rear cover in the same manner as the handle portion 8 of the marnoco 1, and a circuit board on which a control circuit for driving and controlling the motor is mounted is housed in the rear cover.

Next, the gear housing 62 is provided on the side opposite to the rear cover of the motor housing 61 and accommodates a spindle 64 as an output shaft. The spindle 64 is rotatably provided in the gear housing 62 via the internal housing 66.

Further, the spindle 64 is arranged so that the center axis is substantially orthogonal to the rotation axis of the motor. Therefore, the spindle 64 is provided with a bevel gear 68 that converts the rotation of the motor into the rotation of the spindle 64 by meshing with the bevel gear provided on the rotation shaft of the motor.

One end of the spindle 64 protrudes to the outside from the inner housing 66 (in other words, the gear housing 62), and an inner flange 68 for positioning and fixing the disc-shaped tip tool 70 is provided at the protruding portion. ing.

Further, a lock nut 69 is screwed to the outer peripheral portion at the tip of the inner flange 68 of the spindle 64. The lock nut 69 is a member for sandwiching the tip tool 70 with the inner flange 68.

In the grinder 60 configured as described above, the user can hold and operate the grinder 60 by holding the motor housing 61 or the rear cover. Specifically, by turning on an operation switch (not shown) provided on the side wall of the motor housing 61, the motor is driven by the control circuit in the rear cover, and the spindle 64 is driven by the rotational output of the motor. As a result, the tip tool 70 can be rotated.

Therefore, if the tip tool 70 is fixed to the spindle via the lock nut 69, the tip tool 70 can be rotated to perform operations such as grinding, polishing, and cutting. As the tip tool 70 used in the grinder 60 as described above, a grinding wheel, a cutting blade, a wire brush, and the like can be given.

The wheel cover 72 is a member for protecting the user from dust and the like scattered from the workpiece during operations such as grinding, polishing, and cutting. For this reason, the wheel cover 72 has a semicircular shape so as to cover a part (specifically, approximately half) of the outer periphery of the tip tool 70 fixed to the spindle 64 from the gear housing 62 side.

The wheel cover 72 shown in FIG. 5 is a member used when cutting the workpiece, and the outer peripheral portion of the wheel cover 72 is bent so as to surround the outer peripheral edge of the tip tool 70.

The wheel cover 72 is fixed to a portion of the inner housing 66 where the spindle 64 protrudes. That is, in the inner housing 66, the attachment site for attaching the wheel cover 72 is cylindrical so as to surround the spindle 64 concentrically with the central axis of the spindle 64.

As shown in FIG. 6, the wheel cover 72 is provided with a semicircular arc-shaped attachment portion 74 so as to surround the periphery of the attachment portion. An annular fastening member 76 is provided around the attachment portion 74 of the wheel cover 72.

The tightening member 76 has a part of the annular ring that is open, the open end of which is connected by a male screw and a nut, and the inner diameter of the annular ring can be reduced by a lever. Since this configuration is well known, detailed description thereof is omitted here.

Next, the wheel cover 72 is provided with an auxiliary cover 80 for covering an open region of the tip tool 70 that cannot be covered by the wheel cover 72 (in other words, a processing region of the workpiece). The auxiliary cover 80 is a member corresponding to the cover of the present disclosure, and is a rail formed on the wheel cover 72 so as to cover the wheel cover 72 from the outside and move along the outer periphery of the wheel cover 72 around the spindle 64. It is slidably fixed to the portion 72A.

In addition, on the plate surface of the wheel cover 72 on the gear housing 62 side, the engaging member 78A is engaged with a notch 80A formed in the auxiliary cover 80, so that the auxiliary cover 80 is retracted from the tip tool 70. A movable portion 78 is provided for positioning.

The movable portion 78 normally projects the engagement member 78A by the maximum amount outward of the wheel cover 72, and if necessary, the engagement member 78A is moved to the movable portion 78 side by an actuator 90 (see FIG. 8) described later. The amount of protrusion can be minimized.

The wheel cover 72 is provided with a biasing member 82 that biases the auxiliary cover 80 in a direction in which the auxiliary cover 80 protrudes from the wheel cover 72. In this embodiment, the urging member 82 is configured by a coil spring disposed along the inner peripheral surface of the wheel cover 72.

Further, in the auxiliary cover 80, a notch 80 </ b> A that can be engaged with the engaging member 78 </ b> A of the movable portion 78 is provided at an end position opposite to the side protruding from the wheel cover 72 by the biasing member 82. ing. And the protrusion 81 for a user to rotate the auxiliary | assistant cover 80 with a finger | toe is provided in the edge part position.

Accordingly, the user picks up the protrusion 81 and moves the auxiliary cover 80 toward the wheel cover 72 against the urging force of the urging member 82, thereby engaging the notch 80A as shown in FIG. The auxiliary cover 80 can be positioned at the retracted position by engaging the member 78A.

In this state, if a drive command for the actuator 90 is input to the movable portion 78 from the outside, the engagement member 78A is pulled to the movable portion 78 side, and the engagement between the engagement member 78A and the auxiliary cover 80 is engaged. Canceled. Then, as shown in FIG. 7, the auxiliary cover 80 protrudes from the wheel cover 72 by the urging force of the urging member 82 and is positioned at a protection position that covers the outer periphery of the tip tool.

Therefore, also in the grinder 60 of this embodiment, the circuit board provided in the rear cover is configured in the same manner as in the first embodiment shown in FIG. 3, and the control circuit 54 detects the occurrence of kickback via the acceleration sensor 56. In this case, the movable part 78 may be driven.

That is, in this case, when the kickback occurs, the engagement between the engaging member 78A of the movable portion 78 and the notch 80A of the auxiliary cover 80 is released, and the auxiliary cover 80 covers the outer periphery of the tip tool 70. It can be moved to the protected position.

By the way, in order to enable the control circuit 54 to drive the movable portion 78 in this way, the movable portion 78 provided on the wheel cover 72 detachably attached to the main body of the grinder 60 and the main body side of the grinder 60 are provided. It is necessary to electrically connect the control circuit 54. If this connection is made by wire, the wiring of the signal line becomes troublesome.

Therefore, in the present embodiment, as indicated by a dotted line in FIG. 3, the control circuit 54 is provided with a transmission unit 58 that wirelessly transmits a drive command (in other words, an engagement release command). The movable part 78 is connected wirelessly.

Therefore, as shown in FIG. 8, the movable unit 78 is provided with a receiving unit 92, a determining unit 94, and a driving circuit 96 for the actuator 90 in addition to the actuator 90.
Here, the reception unit 92 is for receiving a transmission signal from the transmission unit 58 on the control circuit 54 side, and the determination unit 94 determines whether or not the received signal is a drive command from the control circuit 54. It is for judging.

When the determination unit 94 determines that the drive command from the control circuit 54 has been received, the drive circuit 96 drives the actuator 90 to retract the engagement member 78A, and engage the engagement member 78A and the auxiliary cover 80. Release the engagement.

If wireless communication is performed between the movable portion 78 and the control circuit 54 in this way, there is no need to wire a signal line between the main body side of the grinder 60 and the wheel cover 72, but the grinder 60 It becomes impossible to supply electric power to the movable part 78 from the main body side.

For this reason, the movable part 78 may incorporate a battery to secure a power source for driving the internal circuit, but in this case, it is necessary to replace the battery.
Therefore, in the present embodiment, as shown in FIGS. 5 to 7, the wheel cover 72 is provided with a generator 84 provided with a roller 86 that is in contact with the spindle 64 and rotates by the rotation of the spindle 64. 84 is used as a power source for the movable portion 78.

That is, the generator 84 generates AC power by the rotation of the roller 86. For this reason, the movable part 78 includes a rectifying / smoothing circuit 86 that rectifies and smoothes the output (AC) from the generator 84, and a power supply voltage Vd (for driving the internal circuit) from the output (DC) from the rectifying and smoothing circuit 86. A DC / DC converter 88 that generates a DC constant voltage is provided.

For this reason, in the grinder 60 of the present embodiment, the movable part 78 is not provided with a signal line between the main body side of the grinder 60 and the movable part 78, and without incorporating a battery in the movable part 78. It can be operated.

As mentioned above, although embodiment of this indication was described, the working machine of this indication is not limited to the above-mentioned embodiment, and can take various modes.
For example, in the above embodiment, an example in which kickback is detected using the acceleration sensor 56 has been described. However, an angular velocity sensor that detects an angular velocity around a predetermined axis is used as the detection unit for detecting kickback. You may make it do.

In addition, the kickback is not detected directly using the acceleration sensor or the angular velocity sensor, but is detected from the rotation fluctuation of the motor or the output shaft as described in Patent Document 1. Also good.

In the first embodiment, the example in which the output shaft 14 is used as the rotating member for moving the cover 26 to the protection position has been described. However, the cover 26 is used by using a rotating member different from the output shaft 14. You may make it move to a protection position.

Further, in each of the above embodiments, the cover 26 or the auxiliary cover 80 as a cover of the present disclosure is compared with the saw blade case 20 or the wheel cover 72 that is a main cover that covers a part of the saw blade 16 or the tip tool 70. The example provided so that a movement was possible was demonstrated. However, the cover of the present disclosure may be configured to cover the entire area or substantially the entire area of the tip tool, and the entire cover may be moved between the protection position and the retracted position.

In the above-described embodiment, the marnoco 1 and the grinder 60 have been described as examples of the working machine according to the present disclosure. However, the present disclosure may be performed when the tip tool attached to the output shaft is rotated and brought into contact with the workpiece. In addition, the present invention can be applied to any work machine that may cause a kickback.

Further, in the above-described embodiment, it has been described that the marunoco 1 and the grinder 60 are AC-driven work machines provided with the power cord 44. It may be a DC-driven (in other words, rechargeable) working machine that operates in response to the above.

In the above-described embodiment, the electric working machine including a motor as a driving force source has been described. Even a machine can be applied in the same manner as in the above embodiment.

Further, a plurality of functions of one component in the above embodiment may be realized by a plurality of components, and one function of one component may be realized by a plurality of components. Further, a plurality of functions possessed by a plurality of constituent elements may be realized by one constituent element, or one function realized by a plurality of constituent elements may be realized by one constituent element. Moreover, you may abbreviate | omit a part of structure of the said embodiment. In addition, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of the other embodiment. In addition, all the aspects included in the technical idea specified only by the wording described in the claims are embodiments of the present disclosure.

Claims (6)

An output shaft that can be attached with a tip tool for cutting a workpiece and is rotationally driven by a predetermined driving force source, and a cover for covering at least a part of the outer periphery of the tip tool attached to the output shaft A working machine equipped with
A detection unit for detecting that the work machine is rebounded from the workpiece by a reaction force applied to the tip tool from the workpiece;
A cover moving mechanism that closes the cover and moves to a protective position that covers the outer periphery of the tip tool, when the detection unit detects that the work machine is rebounded from the workpiece;
Working machine equipped with. The cover moving mechanism is
A biasing member that biases the cover toward the protection position;
By engaging the cover, the cover is positioned at a retracted position away from the protection position, and when the detection unit detects that the work machine is rebounded from the workpiece, the cover A movable part that releases the engagement with the biasing member and moves the cover to the protection position by the biasing force of the biasing member;
The working machine according to claim 1, comprising: The cover moving mechanism is configured to engage the rotating member and move the cover to the protection position when the detection unit detects that the work machine is bounced off the workpiece. The working machine according to claim 1. The cover moving mechanism is
An electromagnetic clutch that engages the cover with the rotating member by energization and moves the cover to the protection position;
A controller that energizes the electromagnetic clutch and engages the cover with the rotating member when the detection unit detects that the work machine is rebounded from the workpiece;
The working machine according to claim 3, comprising: The working machine according to claim 3 or 4, wherein the rotating member is the output shaft. 6. The working machine according to claim 3, wherein the cover moving mechanism is configured to frictionally engage the cover with the rotating member.

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