Magnetic drill press

Abstract

To determine whether a magnetic drill press is in a stable state.SOLUTION: A magnetic drill press includes a motor, a drill unit, a main body portion, a magnetic base, and a sensor. The drill unit includes at least a spindle configured to hold a tip tool in a removable manner. The spindle is configured to be driven rotationally around a first axis by the motor. The main body portion supports the drill unit in a manner that the drill unit may move in a first direction parallel to a first axis. The magnetic base is configured to be coupled to the main body portion and selectively fixed to a processed material by magnetic force. The sensor is configured to detect at least one of information corresponding to falling of the magnetic drill press, information corresponding to vibration of the drill unit, and information corresponding to the attitude of the magnetic drill press.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a magnetic drilling machine. [Background technology]

[0002] A magnetic drilling machine is a device that is fixed to a workpiece made of a magnetic substance by magnetic force, and drills holes in the workpiece while moving a rotary blade axially relative to the workpiece (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-157471 A Summary of the Invention [Problem to be solved by the invention]

[0004] Because a magnetic drilling machine is a relatively heavy piece of equipment, it is desirable for the magnetic drilling machine to be maintained stable during use.

[0005] In view of the above-mentioned circumstances, one non-limiting object of the present disclosure is to make it possible to determine whether a magnetic drill press is in a stable state. [Means for solving the problem]

[0006] According to one non-limiting aspect of the present disclosure, a magnetic drilling machine is provided, comprising a motor, a drill unit, a body, a magnetic base, and a sensor. The drill unit includes at least a spindle. The spindle is configured to removably hold a tool tip. The spindle is configured to be rotationally driven by the motor around a first axis. The body supports the drill unit so as to be movable in a first direction parallel to the first axis. The magnetic base is coupled to the body and configured to be selectively fixed to a workpiece by a magnetic force. The sensor is configured to detect at least one of information corresponding to a drop of the magnetic drilling machine, information corresponding to vibration of the drill unit, and information corresponding to an attitude of the magnetic drilling machine.

[0007] The magnetic drilling machine of this embodiment can detect at least one of information corresponding to the fall of the magnetic drilling machine, information corresponding to the vibration of the drill unit, and information corresponding to the posture of the magnetic drilling machine by the sensor. These pieces of information are useful information indicating whether the magnetic drilling machine is in a stable state. Therefore, by effectively utilizing the information detected by the sensor, it can contribute to the improvement of the magnetic drilling machine.

[0008] According to another non-limiting aspect of the present disclosure, there is provided a magnetic drilling machine including a motor, a drill unit, an intermediate section, a magnetic base, and an acceleration sensor or an angular velocity sensor. The drill unit includes at least a spindle configured to removably hold a tool tip and configured to be rotationally driven by the motor. The intermediate section movably supports the drill unit. The magnetic base is coupled to the intermediate section and configured to be selectively fixed to a workpiece by magnetic force.

[0009] The magnetic drilling machine of this embodiment can detect information about the movement or posture of the magnetic drilling machine by an acceleration sensor or an angular velocity sensor. This information is useful information indicating whether the magnetic drilling machine is in a stable state or not. Therefore, by effectively utilizing the information detected by the sensor, it is possible to contribute to the improvement of the magnetic drilling machine. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of a magnetic drilling machine according to a first embodiment. [Diagram 2] FIG. 2 is another perspective view of the magnetic drilling machine. [Diagram 3] FIG. 2 is a left side view of the magnetic drilling machine. [Figure 4] FIG. [Diagram 5] FIG. 11 is a perspective view of a magnetic drilling machine according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In a non-limiting embodiment of the present disclosure, the magnetic drilling machine may further include a control device configured to control the operation of the magnetic drilling machine based on the information detected by the sensor. The control device may be embodied, for example, by at least one processor / processing circuit and a memory. The control device may be configured to stop driving the motor when the information indicates that the magnetic drilling machine has fallen. According to this embodiment, it is possible to prevent the tip tool from being rotated when the magnetic drilling machine has fallen and is separated from the workpiece.

[0012] In addition to or instead of the above embodiment, the control device may be configured to stop driving the motor when the information indicates vibration of the drill unit exceeding a predetermined threshold. Since the drill unit is supported on the body so as to be movable in the first direction, for example, an unexpected backlash may occur due to loosening of the connection of the support structure caused by operation, which may cause vibration of the drill unit. The greater the vibration, the lower the accuracy of the hole formed by the tool tip. According to this embodiment, when the vibration becomes severe enough, the motor is stopped, so that the user can check the backlash of the support structure and take necessary measures.

[0013] In addition to or instead of the above embodiment, the sensor may be capable of detecting a first position when the magnetic base is placed on the workpiece and a second position different from the first position as the position of the magnetic drilling machine. When the information indicates that the magnetic drilling machine is in the second position, the control device may be configured to control the operation of the magnetic drilling machine in a manner different from that when the information indicates that the magnetic drilling machine is in the first position. When the magnetic drilling machine is in the first position in which the magnetic base is placed on the workpiece (supported by the workpiece), it can be said that the magnetic drilling machine is in a stable state compared to when it is in other positions. Therefore, by differentiating the operation control when the magnetic drilling machine is in the first position and when it is in the second position of the control device, rational control can be realized.

[0014] In addition to or instead of the above embodiment, the magnetic drilling machine may further include a first detector configured to detect the fastener when the fastener is attached to the main body or the magnetic base. The fastener is configured to connect the main body or the magnetic base to the workpiece. The control device may be configured to drive the motor regardless of the detection result of the first detector when the information indicates that the magnetic drilling machine is in the first position. The control device may further be configured to drive the motor on condition that the fastener is detected by the first detector when the information indicates that the magnetic drilling machine is in the second position. The fastener is an auxiliary device used to prevent the magnetic drilling machine from coming off the workpiece. In this embodiment, when the magnetic drilling machine is in the second position, the motor is not driven unless the fastener is attached, so that the magnetic drilling machine can be prevented from being driven in an unstable state. In addition, for example, a microswitch or a load sensor can be adopted as the first detector.

[0015] In addition to or instead of the above embodiment, the magnetic drilling machine may further include an indicator configured to notify the detection information detected by the sensor or information based on the detection information. According to this embodiment, the user can easily recognize the state of the magnetic drilling machine by the information notified by the indicator and take appropriate measures.

[0016] In addition to or instead of the above embodiment, the sensor may be an acceleration sensor or an angular velocity sensor. According to this embodiment, at least one of information corresponding to the drop of the magnetic drilling machine, information corresponding to the vibration of the drill unit, and information corresponding to the posture of the magnetic drilling machine can be detected using an existing sensor that is easily available.

[0017] In addition to or instead of the above embodiment, the sensor may be a single (only one) acceleration sensor configured to detect information corresponding to the drop of the magnetic drill press, information corresponding to the vibration of the drill unit, and information corresponding to the attitude of the magnetic drill press. According to this embodiment, it is possible to detect multiple types of information useful for controlling the magnetic drill press with fewer parts than when each piece of information is detected by a separate sensor.

[0018] In addition to or instead of the above embodiment, the magnetic drilling machine may further include a second detector configured to detect that the tool bit held by the spindle is within a predetermined distance from the workpiece. The control device may be configured to drive the motor at a predetermined first speed in response to the second detector detecting that the tool bit is within the predetermined distance from the workpiece. According to this embodiment, the motor can be driven at a rotational speed appropriate for the processing operation in response to the tool bit approaching the workpiece and being positioned within the predetermined distance as the drill unit moves.

[0019] In addition to or instead of the above embodiment, the magnetic drilling machine may further include a motor switch configured to be manually operated by a user. The control device may be configured to start driving the motor at a second speed slower than the first speed in response to the motor switch being turned on, and then change the rotation speed of the motor to the first speed in response to the second detector detecting that the tool tip is within a predetermined distance from the workpiece. According to this embodiment, it is possible to reduce wasteful power consumption compared to a case in which the motor is immediately started to be driven at the first speed in response to the switch being turned on. Note that the first speed may be any speed higher than the second speed, but is preferably the maximum speed of the motor.

[0020] In addition to or instead of the above embodiment, the spindle may have an insertion hole extending along the first axis and configured to receive a part of a pilot pin held by the tool bit so as to be movable along the first axis. The second detector may be a load sensor arranged in the insertion hole of the spindle so as to receive the load of the pilot pin. The pilot pin is a well-known component for aligning the rotation axis of the spindle of the magnetic drilling machine to a desired position, and is removably held by the tool bit for use. According to this embodiment, it is possible to detect that the tool bit is within a predetermined distance from the workpiece based on the load received by the load sensor from the pilot pin.

[0021] In addition to or instead of the above embodiment, the second detector may be a distance sensor or a proximity sensor disposed in the drill unit, which can detect with a simple configuration that the tool bit is within a predetermined distance from the workpiece.

[0022] Representative and non-limiting embodiments of the present disclosure will be described in detail below with reference to the drawings.

[0023] First Embodiment A magnetic drilling machine 1A according to a first embodiment will be described with reference to Figs. 1 to 4. The magnetic drilling machine 1A is a portable electric tool. More specifically, the magnetic drilling machine 1A is an electric tool configured to drill holes in a workpiece made of a magnetic material (e.g., iron) using an electric drill while being fixed to the workpiece using magnetic force. The magnetic drilling machine 1A is also called a magnetic drill or a magnetic drilling device.

[0024] First, a schematic configuration of the magnetic drilling machine 1A will be described. As shown in FIG. 1 and FIG. 2, the magnetic drilling machine 1A includes a magnetic base 2 configured to be selectively fixed to a workpiece by magnetic force, a main body 3 connected to the magnetic base 2, and a drill unit 4 supported by the main body 3. The drill unit 4 includes a spindle 41 configured to removably hold a tip tool 91 (e.g., an annular cutter, a twist drill bit). The drill unit 4 is supported by the main body 3 so as to be movable in a direction substantially parallel to the rotation axis R1 of the spindle 41 relative to the main body 3. The drill unit 4 moves in response to a handle 32 provided on the main body 3 being manually operated by a user. While the drill unit 4 is moved in a direction approaching the workpiece, a hole is formed in the workpiece by the tip tool 91 rotated together with the spindle 41.

[0025] The detailed configuration of the magnetic drilling machine 1A will be described below.

[0026] First, the magnetic base 2 will be described. As shown in Figs. 2 and 3, the magnetic base 2 includes a holder 21 having an abutment surface 211 that can abut against the workpiece, and a magnet 20 supported by the holder 21. In this embodiment, a permanent magnet is used for the magnet 20. The magnet 20 is supported by the holder 21 so as to be rotatable around a rotation axis R2 (see Fig. 3). The rotation axis R2 extends in a direction substantially perpendicular to the rotation axis R1 of the spindle 41. Although detailed illustration and description are omitted because this is a well-known technique, the magnetic force acting on the workpiece changes according to the change in the position of the magnet 20 around the rotation axis R2. When the magnet 20 is placed at a predetermined position around the rotation axis R2, the workpiece is attracted to the abutment surface 211 by the magnetic force generated by the magnet 20 and fixed.

[0027] In the following description, for convenience, the extension direction of the rotation axis R1 of the spindle 41 is defined as the vertical direction of the magnetic drilling machine 1A. In the vertical direction, the side where the abutment surface 211 is located is defined as the lower side of the magnetic drilling machine 1A, and the opposite side is defined as the upper side. In addition, the extension direction of the rotation axis R2 of the magnet 20 is defined as the front-rear direction of the magnetic drilling machine 1A. In the front-rear direction, the side where the spindle 41 is located with respect to the magnetic base 2 is defined as the front side of the magnetic drilling machine 1A, and the opposite side is defined as the rear side. In addition, the direction perpendicular to the rotation axis R1 of the spindle 41 and the rotation axis R2 of the magnet 20 is defined as the left-right direction of the magnetic drilling machine 1A.

[0028] Next, the main body 3 will be described. As shown in Figs. 1 to 3, the main body 3 is connected to the magnetic base 2 on the opposite side to the contact surface 211 in the vertical direction of the magnetic drilling machine 1A. In other words, the main body 3 is disposed above the magnetic base 2. The main body 3 is a support that supports the drill unit 4, and is also called a drill stand.

[0029] A manual operation member 35 for rotating the magnet 20 is disposed at the lower rear end of the main body 3. In this embodiment, the manual operation member 35 is a knob that can rotate around an axis parallel to the rotation axis R2, and is operably connected to the magnet 20. A user can rotate the magnet 20 around the rotation axis R2 by operating the manual operation member 35 (rotating the knob), thereby changing the strength of the magnetic force acting on the workpiece, that is, the degree of fixation of the magnetic base 2 to the workpiece. The manual operation member 35 for rotating the magnet 20 may be, for example, a slide-type lever. The manual operation member 35 may be provided on the magnetic base 2 instead of the main body 3.

[0030] The main body 3 has a battery mounting section 33 configured to detachably receive the battery 93. The battery 93 is, for example, a rechargeable battery that can be used for various electric tools other than the magnetic drilling machine 1A. Since this is a well-known configuration, detailed illustration is omitted, but the battery mounting section 33 includes a pair of rails that can be physically slidably engaged with a pair of grooves formed in the battery 93, and a terminal section having a terminal that can be electrically connected to the terminal of the battery 93. In this embodiment, the battery mounting section 33 is disposed at the rear end of the main body 3, and is configured so that the battery 93 is mounted from above. However, the mounting direction of the battery 93 may be other directions. In addition, the magnetic drilling machine 1A may be configured to operate with power supplied from an external commercial power source via a power cord instead of the battery 93.

[0031] As shown in Fig. 3, a gap (passage) extending in the left-right direction is provided between a part of the main body 3 and a part of the magnetic base 2 in the up-down direction. This gap is a slot 37 for passing the fastener 95. The fastener 95 in this embodiment is a long, thin strap, but other fasteners such as a chain can also be used. The fastener 95 is passed through the slot 37 and tightened around the magnetic base 2 and the workpiece, so that the magnetic drilling machine 1A is securely connected to the workpiece so that it cannot be separated from the workpiece.

[0032] The magnetic drilling machine 1A can be used by placing it on the workpiece with the contact surface 211 of the magnetic base 2 (and thus the tip of the tip tool 91) facing vertically downward, that is, toward the direction of gravity (hereinafter simply referred to as the downward position). When the magnetic drilling machine 1A is in the downward position, the magnetic drilling machine 1A is in a stable state and is unlikely to fall off the workpiece.

[0033] On the other hand, when the magnetic drilling machine 1A is used in a position other than the downward position, if the magnetic force is not fixed / insufficiently, the magnetic drilling machine 1A may fall. In particular, care must be taken when the magnetic drilling machine 1A is used in a position in which the contact surface 211 faces vertically upward, that is, in the direction opposite to the direction of gravity (hereinafter simply referred to as the upward position), or in a position in which the contact surface 211 is approximately parallel to the vertical direction (hereinafter simply referred to as the vertical position), or in a position between these. Therefore, when the magnetic drilling machine 1A is used in the upward position, vertical position, or a position between these, the use of the fixing device 95 is recommended.

[0034] As shown in Fig. 3, in this embodiment, a microswitch 53 configured to detect the attachment of the fixture 95 is disposed on the upper surface of the magnetic base 2 within the slot 37. The microswitch 53 is normally kept off and is configured to be turned on when the fixture 95 is passed through the slot 37 and tightened around the magnetic base 2 and the workpiece. The microswitch 53 is electrically connected to a controller 50 (see Fig. 4) described later, and outputs a signal indicating the on / off state. Note that a load sensor may be used to detect the attachment of the fixture 95 instead of the microswitch 53.

[0035] The following describes the connection structure between the main body 3 and the drill unit 4. As described above, the drill unit 4 is connected to the main body 3 so as to be movable in the up and down directions relative to the main body 3. More specifically, as shown in Figures 1, 3 and 4, the main body 3 and the drill unit 4 are connected via a rail 30 provided on the main body 3 and a rack 47 provided on the drill unit 4.

[0036] The rail 30 is disposed at the front end of the main body 3 and extends linearly in the vertical direction. The rack 47 is rod-shaped and extends vertically, disposed at the rear end of the drill unit 4 (specifically, fixed to the rear end of the housing 40 described later), and engaged with the rail 30 so as to be slidable in the vertical direction. Although detailed illustration is omitted, teeth of the rack 47 are formed on the rear surface of the rack 47. The rack 47 meshes with the pinion 321. The pinion 321 is operably connected to the handle 32 that can be manually operated by the user. When the pinion 321 is rotated in response to manual operation of the handle 32, the drill unit 4 having the rack 47 is moved linearly in the vertical direction relative to the main body 3.

[0037] Thus, in this embodiment, the rack 47 and the pinion 321 constitute a movement mechanism of the drill unit 4 relative to the main body 3. The rack 47 also constitutes a part of a connecting structure that connects the drill unit 4 and the main body 3 so as to be relatively movable in the up-down direction. However, the connecting structure and the moving mechanism between the drill unit 4 and the main body 3 are not limited to this example, and any known connecting structure and moving mechanism may be adopted. For example, a feed screw mechanism including a feed screw shaft and a nut may be adopted as the moving mechanism of the drill unit 4. Also, for example, the connecting mechanism and the moving mechanism may be provided separately.

[0038] The drill unit 4 will be described in detail below. As shown in Fig. 4, the drill unit 4 of this embodiment includes a housing 40, a spindle 41, a motor 43, and a controller 50. The spindle 41, the motor 43, and the controller 50 are accommodated in the housing 40.

[0039] The spindle 41 is supported rotatably around a rotation axis R1 relative to the housing 40. A lower end of the spindle 41 protrudes downward from the lower end of the housing 40. The lower end of the spindle 41 has a tool attachment portion 410 configured to removably hold the tool tip 91. The tool attachment portion 410 is also called a chuck, an arbor, or the like. The tool attachment portion 410 holds the tool tip 91 such that the central axis of the tool tip 91 coincides with the rotation axis R1.

[0040] The spindle 41 has an insertion hole 415 that extends linearly upward along the rotation axis R1 from the lower end of the spindle 41. The insertion hole 415 is configured to receive the pilot pin 92. A spring 416 for biasing the pilot pin 92 is housed in the insertion hole 415.

[0041] The pilot pin 92 is a well-known part used as an auxiliary to align the rotation axis R1 of the spindle 41, and therefore the center of a hole formed in the workpiece by the tool tip 91, to a desired point on the workpiece. The pilot pin 92 is inserted into a through hole 911 of the tool tip 91 and is held so as to be linearly movable along the central axis of the tool tip 91. When the tool tip 91 holding the pilot pin 92 is attached to the tool attachment portion 410 of the spindle 41, the upper end of the pilot pin 92 is positioned within the insertion hole 415, and the pilot pin 92 is urged downward by a spring 416.

[0042] In the initial state where no upward force is applied to the pilot pin 92, the lower end of the pilot pin 92 protrudes downward from the lower end of the tip tool 91. Therefore, the user can align the magnetic drilling machine 1A with respect to the workpiece using the tip of the pilot pin 92 as a mark. The pilot pin 92 is pressed against the workpiece during the drilling operation and is pushed upward against the biasing force of the spring 416.

[0043] The motor 43 is operably connected to the spindle 41 and configured to rotate and drive the spindle 41. In this embodiment, an output shaft 431 of the motor 43 extends parallel to the spindle 41 and is connected to the spindle 41 via a reduction gear train.

[0044] The controller 50 is a control device configured to control the operation of the magnetic drilling machine 1A. The controller 50 includes at least a control circuit mounted on a circuit board. In this embodiment, the controller 50 is configured by a microcomputer including a CPU and a memory.

[0045] In this embodiment, the controller 50 is electrically connected to the motor 43 , the motor switch 44 , the acceleration sensor 51 , the microswitch 53 , the load sensor 55 , and the indicator lamp 59 .

[0046] The motor switch 44 is configured to be manually operated by a user to instruct the start of the motor 43. As shown in Figs. 1 and 4, in this embodiment, the motor switch 44 is disposed at the upper end of the housing 40. The motor switch 44 is configured to be switched on and off in response to manual operation by the user. A signal indicating the on / off state output from the motor switch 44 is used by the controller 50 to control the start and stop of driving of the motor 43.

[0047] As shown in Fig. 4, the acceleration sensor 51 is attached to the housing 40. The acceleration sensor 51 of this embodiment detects information corresponding to the drop of the magnetic drilling machine 1A, information corresponding to the vibration of the drill unit 4, and information corresponding to the attitude of the magnetic drilling machine 1A, and outputs corresponding signals. Specifically, the acceleration sensor 51 is a three-axis acceleration sensor that detects acceleration in each of three mutually orthogonal directions (X-axis, Y-axis, and Z-axis). The signal output from the acceleration sensor 51 is used for the operation control of the magnetic drilling machine 1A by the controller 50, for example, as described below.

[0048] The acceleration sensor 51 can detect, for example, signals indicating the acceleration in each of the three directions as information corresponding to the fall of the magnetic drilling machine 1A. When the magnetic drilling machine 1A is in a free fall state, the acceleration in each of the three directions is zero, and the sum of these is substantially zero. In this embodiment, when the controller 50 determines, based on the signal output from the acceleration sensor 51, that the state in which the sum of the acceleration in the three directions is zero (free fall state) continues for a predetermined time while the motor 43 is being driven, the controller 50 stops the drive of the motor 43. By such control, it is possible to prevent the tip tool 91 from continuing to rotate when the magnetic drilling machine 1A is separated from the workpiece.

[0049] In addition, the acceleration sensor 51 can detect, for example, an acceleration in a direction intersecting the vertical direction as information corresponding to the vibration of the drill unit 4. The vibration of the drill unit 4 is typically caused by a backlash in the connection structure between the main body 3 and the drill unit 4. As described above, in this embodiment, the main body 3 and the drill unit 4 are connected by sliding engagement between the rail 30 and the rack 47. Generally, the backlash is within an allowable range at the time of shipment. However, when the connection loosens and the backlash increases with use of the magnetic drilling machine 1A, the vibration mainly increases in a direction intersecting the vertical direction.

[0050] Therefore, in this embodiment, when the controller 50 determines based on the signal output from the acceleration sensor 51 that the vibration in a predetermined direction (e.g., left-right direction) intersecting the up-down direction during the driving of the motor 43 exceeds a predetermined threshold, the controller 50 stops the driving of the motor 43. This control makes it possible to prevent the magnetic drilling machine 1A from continuing the work in an unstable state. It is also possible to prevent the shape and dimensions of the hole formed by the tip tool 91 from being significantly changed from the original shape and dimensions due to the vibration.

[0051] In addition, the acceleration sensor 51 can detect the pitch angle or the angle of the rotation axis R1 relative to the direction of gravity as information corresponding to the attitude of the magnetic drilling machine 1A. The controller 50 can identify the attitude of the magnetic drilling machine 1A based on the signal output from the acceleration sensor 51. As described above, if the fixing device 95 is not attached when the magnetic drilling machine 1A is used in an upward or vertical position, the possibility of the magnetic drilling machine 1A falling increases. Whether or not the fixing device 95 is attached can be determined from the detection result of the microswitch 53.

[0052] Therefore, in this embodiment, when the controller 50 determines that the magnetic drilling machine 1A is in a downward position, the motor switch 44 is turned on to start driving the motor 43, regardless of the detection result of the microswitch 53. On the other hand, when the controller 50 determines that the magnetic drilling machine 1A is in a position other than the downward position (e.g., an upward position or a vertical position), the controller 50 drives the motor 43 only when it determines that the fixture 95 is attached based on the signal output from the microswitch 53. In other words, when the magnetic drilling machine 1A is in a position other than the downward position and the fixture 95 is not attached, the controller 50 does not drive the motor 43 even if the motor switch 44 is turned on. Therefore, it is possible to prevent the magnetic drilling machine 1A from being driven in an unstable state.

[0053] In this embodiment, three types of information corresponding to the drop of the magnetic drilling machine 1A, the vibration of the drill unit 4, and the posture of the magnetic drilling machine 1A are detected by only one acceleration sensor 51, and are used for controlling the operation of the magnetic drilling machine 1A. Therefore, information useful for controlling the magnetic drilling machine 1A can be detected with a smaller number of parts than when each piece of information is detected by a separate sensor.

[0054] As shown in Fig. 4, the load sensor 55 is attached inside the insertion hole 415 of the spindle 41 described above. More specifically, the load sensor 55 is disposed within the upper end of the insertion hole 415, above the spring 416. The load sensor 55 receives a load as the pilot pin 92 is pressed against the workpiece and compresses the spring 416. The load detected by the load sensor 55 increases as the pilot pin 92 moves upward, that is, as the vertical distance between the tip of the tool bit 91 and the workpiece decreases.

[0055] Therefore, while the controller 50 determines based on the signal output from the load sensor 55 that the detected load is lower than a predetermined threshold, that is, that the tip tool 91 is away from the workpiece by more than a predetermined distance, the controller 50 drives the motor 43 at an initial speed lower than the maximum speed. When the load detected by the load sensor 55 becomes equal to or greater than the predetermined threshold, that is, when the tip tool 91 approaches the workpiece by a predetermined distance, the controller 50 increases the rotation speed of the motor 43 and drives the motor 43 at the maximum speed. The load threshold is preferably set to a load detected by the load sensor 55 when the tip of the tip tool 91 is located 1 to 2 centimeters (cm) above the workpiece, for example.

[0056] In addition, the magnetic drilling machine 1A can selectively attach multiple types of tip tools 91 with different axial lengths, and the load sensor 55 can detect when the tip tool 91 has approached a predetermined distance from the workpiece regardless of the length of the tip tool 91.

[0057] According to such control, after the user turns on the motor switch 44, while the user operates the handle 32 to lower the drill unit 4, the rotation speed of the motor 43 is maintained at a low speed until the tip tool 91 reaches a predetermined distance from the workpiece. This makes it possible to suppress unnecessary power consumption. In particular, when the battery 93 is used as the power source as in this embodiment, there is an advantage that the runtime of the battery 93 can be extended. In addition, since the tip tool 91 rotates at a low speed while approaching the workpiece to a predetermined distance, the rotation speed of the tip tool 91 can be efficiently increased to the maximum speed at the time when the tip tool 91 approaches the workpiece to a predetermined distance.

[0058] Instead of the above-mentioned control, the controller 50 may not start driving the motor 43 until the tool tip 91 reaches a predetermined distance from the workpiece. In this case, there is an advantage in that power consumption can be further reduced compared to when driving at a low speed. Also, a plurality of loads corresponding to different distances between the tool tip 91 and the workpiece may be preset in stages, and the controller 50 may increase the rotation speed of the motor 43 in stages according to the detected load.

[0059] The load sensor 55 can indirectly detect that the distance between the tip of the tool bit 91 and the workpiece is equal to or less than a predetermined distance by detecting the load received from the pilot pin 92. Alternatively, a contact switch may be disposed in the insertion hole 415 of the spindle 41, and a plunger of the switch may be operated by the upper end of the pilot pin 92 when the distance between the tip of the tool bit 91 and the workpiece is equal to or less than the predetermined distance.

[0060] The indicator lamp 59 is a device that notifies the user of information indicating the state of the magnetic drilling machine 1A. As shown in FIG. 1, the indicator lamp 59 in this embodiment is disposed on the upper surface of the housing 40. The indicator lamp 59 is configured with an LED, and is switched between a lighted state and an unlighted state by the controller 50. The indicator lamp 59 is turned on, for example, when an abnormality occurs in the magnetic drilling machine 1A or when it is necessary to prompt the user to take action. Specifically, as described above, the indicator lamp 59 is turned on when the motor 43 is stopped in response to the drop of the magnetic drilling machine 1A or the vibration generation of the drill unit 4, or when the fixing device 95 is not attached. In addition, when there are multiple pieces of information to be notified, multiple LEDs may be provided corresponding to each piece of information.

[0061] <Second embodiment> Hereinafter, a magnetic drilling machine 1B according to a second embodiment of the present disclosure will be described with reference to FIG.

[0062] The magnetic drilling machine 1B of the second embodiment differs from the magnetic drilling machine 1A of the first embodiment in that it includes a distance measuring sensor 57 and a distance setting button 58 instead of the load sensor 55, but the other configurations are substantially the same as those of the magnetic drilling machine 1A. Therefore, in the following description, the same configurations as those of the first embodiment will not be described.

[0063] The distance measuring sensor 57 is attached facing downward to the housing 40 of the drill unit 4. For example, a photoelectric sensor can be used as the distance measuring sensor 57. The distance measuring sensor 57 is electrically connected to the controller 50 and outputs a signal indicating the distance between the distance measuring sensor 57 and the workpiece.

[0064] When the motor switch 44 is turned on, the controller 50 starts driving the motor 43. Specifically, the controller 50 drives the motor 43 at an initial speed lower than the maximum speed while the controller 50 determines that the detected distance is longer than a predetermined reference distance based on the signal output from the distance measuring sensor 57. Alternatively, the controller 50 does not start driving the motor 43 while the controller 50 determines that the detected distance is longer than a predetermined reference distance. When the distance detected by the distance measuring sensor 57 becomes equal to or shorter than the reference distance, the controller 50 increases the rotation speed of the motor 43 and drives the motor 43 at the maximum speed. Note that the reference distance is preferably set to the distance between the distance measuring sensor 57 and the workpiece when the tip of the tip tool 91 is located 1 to 2 cm above the workpiece, for example.

[0065] The distance setting button 58 is an operating member that can be manually operated by the user to set the above-mentioned reference distance. In this embodiment, the distance setting button 58 is arranged at the front end of the housing 40 so as to be pressable, and is electrically connected to the controller 50. As described above, the magnetic drilling machine 1B can selectively mount a plurality of types of tip tools 91 having different axial lengths. Therefore, the memory of the controller 50 stores reference distances corresponding to the respective lengths. By pressing the distance setting button 58, the user can select the type of tip tool 91 to be actually used and set an appropriate reference distance corresponding to the selected type. The controller 50 controls the driving of the motor 43 as described above based on the reference distance set via the distance setting button 58.

[0066] The magnetic drilling machine 1B may be provided with an indicator (for example, an LED lamp, a display) that notifies information about the tip tool 91 selected by the user.

[0067] As described above, in this embodiment, similarly to the first embodiment, after the user turns on the motor switch 44, while the user operates the handle 32 to lower the drill unit 4, the motor 43 is maintained in a low-speed driving state or in a stopped state until the tip tool 91 approaches the workpiece to a certain extent. This makes it possible to reduce unnecessary power consumption. In addition, since the reference distance according to the length of the tip tool 91 actually used can be set, the controller 50 can change the rotation speed of the motor 43 at an appropriate timing.

[0068] In this embodiment, the distance measuring sensor 57 has a relatively long detection distance because of its mounting position in the housing 40. However, if the mounting position can be set lower on the drill unit 4, a proximity sensor with a shorter detection distance than the distance measuring sensor 57 may be used. The controller 50 can increase the rotation speed of the motor 43 as described above in response to the proximity sensor detecting a workpiece within a predetermined distance.

[0069] The correspondence between each component (feature) of the above embodiment and each component (feature) of the present disclosure or invention is shown below. However, each component of the embodiment is merely an example and does not limit each component of the present disclosure or invention.

[0070] Each of the magnetic drilling machines 1A and 1B is an example of a "magnetic drilling machine". The motor 43 is an example of a "motor". The drill unit 4 and the spindle 41 are examples of a "drill unit" and a "spindle", respectively. The main body 3 is an example of a "main body" and a "middle part". The magnetic base 2 is an example of a "magnetic base". The acceleration sensor 51 is an example of a "sensor". The controller 50 is an example of a "control device". The microswitch 53 is an example of a "first detector". The fixture 95 is an example of a "fixture". The indicator lamp 59 is an example of an "indicator". Each of the load sensor 55 and the distance measuring sensor 57 is an example of a "second detector". The motor switch 44 is an example of a "motor switch". The pilot pin 92 is an example of a "pilot pin". The insertion hole 415 is an example of an "insertion hole".

[0071] It should be noted that the above embodiment is merely an example, and the magnetic drilling machine according to the present disclosure is not limited to the magnetic drilling machines 1A and 1B illustrated. For example, non-limiting modifications exemplified below can be added. In addition, at least one of these modifications can be adopted in combination with the magnetic drilling machines 1A and 1B illustrated in the embodiment, and any of the inventions described in the claims.

[0072] For example, the magnetic base 2 only needs to be capable of selectively applying the magnetic force generated by the magnet 20 to the workpiece, thereby attracting and fixing the workpiece to the contact surface 211, and there is no particular limitation on the method of switching the type of magnet 20 and / or the strength of the magnetic force.

[0073] For example, the magnet 20 may be an electromagnet, and the controller 50 may control the energization and deenergization of the electromagnet to switch between a fixed state and an unfixed state. The controller 50 may also control the strength of the magnetic force acting on the workpiece.

[0074] When an electromagnet is used instead of the magnet 20, the manual operation member 35 may be an information input device (for example, a push button switch, a touch screen, etc.) electrically connected to the controller 50. The manual operation member 35 may be provided on the magnetic base 2 instead of the main body 3.

[0075] The motor 43 and / or the controller 50 do not necessarily have to be included in the drill unit 4, and may be housed inside the main body 3. The motor switch 44, the indicator lamp 59, and the distance setting button 58 may also be provided on the main body 3.

[0076] The acceleration sensor 51 may detect only one or two of the three types of information corresponding to the drop of the magnetic drilling presses 1A and 1B, the vibration of the drill unit 4, and the attitude of the magnetic drilling presses 1A and 1B, instead of all three types of information. In response to such a change, the controller 50 may perform only the control corresponding to the detected information among the above-mentioned controls. Also, instead of or in addition to the acceleration sensor 51, another sensor may be adopted. For example, an angular velocity sensor (gyro sensor) may be adopted as a sensor that detects information corresponding to the vibration of the drill unit 4.

[0077] The controller 50 may perform control other than the control exemplified in the embodiment based on the detection result of the acceleration sensor 51 or the sensor of the above modification. The following are non-limiting examples of control that can be adopted.

[0078] For example, when an electromagnet is used in the magnetic base 2, the controller 50 can control the strength of the magnetic force of the electromagnet according to the posture of the magnetic drilling machines 1A, 1B detected by the acceleration sensor 51. Specifically, when it is detected that the magnetic drilling machines 1A, 1B are in a posture between the vertical posture and the upward posture, the controller 50 controls the magnetic force to be the strongest. When it is detected that the magnetic drilling machines 1A, 1B are in a downward posture, the controller 50 controls the magnetic force to be weaker.

[0079] Although the illustration is omitted because it is a well-known configuration, a container for storing a cooling liquid can be attached to the magnetic drilling machines 1A and 1B. However, since the container is assumed to be used when the magnetic drilling machines 1A and 1B are in a downward position, the cooling liquid may leak when the magnetic drilling machines 1A and 1B are used in an upward or vertical position. Therefore, the magnetic drilling machines 1A and 1B may further include a detector (e.g., a microswitch, a load sensor) that detects the attachment of the container. The controller 50 may report appropriate information based on the detection result of this detector and the position of the magnetic drilling machines 1A and 1B detected by the acceleration sensor 51. Specifically, when it is detected that the container is attached and that the magnetic drilling machines 1A and 1B are in a position between the vertical position and the upward position, the controller 50 reports an error. For example, an indicator lamp 59 may be used for the report. [Explanation of symbols]

[0080] 1A, 1B: magnetic drill press, 2: magnetic base, 20: magnet, 21: holder, 211: contact surface, 3: main body, 30: rail, 32: handle, 321: pinion, 33: battery mounting part, 35: manual operation member, 37: slot, 4: drill unit, 40: housing, 41: spindle, 410: tool mounting part, 415: insertion hole, 416: spring, 43: motor, 431: output shaft, 44: motor switch, 47: rack, 50: controller, 51: acceleration sensor, 53: microswitch, 55: load sensor, 57: distance measuring sensor, 58: distance setting button, 59: indicator lamp, 91: tip tool, 911: through hole, 92: pilot pin, 93: battery, 95: fixture

Claims

1. A magnetic drilling machine, A motor; a drill unit configured to removably hold a tool bit and including at least a spindle configured to be rotatably driven by the motor about a first axis; a body portion supporting the drill unit so as to be movable in a first direction parallel to the first axis; a magnetic base coupled to the body portion and configured to be selectively secured to a workpiece by magnetic force; A magnetic drilling machine comprising a sensor configured to detect at least one of information corresponding to a fall of the magnetic drilling machine, information corresponding to vibration of the drill unit, and information corresponding to the posture of the magnetic drilling machine.

2. 2. The magnetic drilling machine according to claim 1, A control device configured to control an operation of the magnetic drilling machine based on information detected by the sensor, The magnetic drilling machine, characterized in that the control device is configured to stop driving the motor when the information indicates that the magnetic drilling machine has fallen.

3. The magnetic drilling machine according to claim 1 or 2, A control device configured to control an operation of the magnetic drilling machine based on information detected by the sensor, The magnetic drilling machine, characterized in that the control device is configured to stop driving the motor if the information indicates vibration of the drill unit exceeding a predetermined threshold.

4. The magnetic drilling machine according to any one of claims 1 to 3, A control device configured to control an operation of the magnetic drilling machine based on information detected by the sensor, The sensor is capable of detecting, as the posture of the magnetic drilling machine, a first posture when the magnetic base is placed on the workpiece and a second posture different from the first posture, The control device is configured to control the operation of the magnetic drilling machine in a manner different from when the information indicates that the magnetic drilling machine is in the second position, when the information indicates that the magnetic drilling machine is in the first position.

5. 5. The magnetic drilling machine according to claim 4, a first detector configured to detect a fastener configured to couple the body or the magnetic base to the workpiece when the fastener is attached to the body or the magnetic base; The control device includes: When the information indicates that the magnetic drilling machine is in the first attitude, the motor is driven regardless of the detection result of the first detector; and A magnetic drilling machine characterized in that, when the information indicates that the magnetic drilling machine is in the second position, the motor is driven on the condition that the fixing device is detected by the first detector.

6. The magnetic drilling machine according to any one of claims 1 to 5, A magnetic drilling machine further comprising an indicator configured to report detection information detected by the sensor or information based on the detection information.

7. The magnetic drilling machine according to any one of claims 1 to 6, The magnetic drilling machine is characterized in that the sensor is an acceleration sensor or an angular velocity sensor.

8. 8. The magnetic drilling machine according to claim 7, A magnetic drilling machine characterized in that the sensor is a single acceleration sensor configured to detect information corresponding to the fall of the magnetic drilling machine, information corresponding to the vibration of the drill unit, and information corresponding to the posture of the magnetic drilling machine.

9. The magnetic drilling machine according to any one of claims 1 to 8, A control device configured to control an operation of the magnetic drilling machine based on information detected by the sensor, a second detector configured to detect when the tool bit held by the spindle is within a predetermined distance from the workpiece; The control device is configured to drive the motor at a predetermined first speed in response to detection by the second detector that the tool tip is within the predetermined distance from the workpiece.

10. 10. The magnetic drilling machine according to claim 9, a motor switch configured to be manually operated by a user; The control device is configured to start driving the motor at a second speed slower than the first speed in response to the motor switch being turned on, and then change the rotational speed of the motor to the first speed in response to the second detector detecting that the tool tip is within the specified distance from the workpiece.

11. The magnetic drilling machine according to claim 9 or 10, the spindle has an insertion hole extending along the first axis and configured to receive a portion of a pilot pin held by the tool bit so as to be movable along the first axis; A magnetic drilling machine characterized in that the second detector is a load sensor arranged within the insertion hole of the spindle so as to receive a load from the pilot pin.

12. The magnetic drilling machine according to claim 9 or 10, A magnetic drilling machine characterized in that the second detector is a distance measuring sensor or a proximity sensor arranged in the drill unit.

13. A motor; A drill unit including at least a spindle configured to removably hold a tool bit and to be rotatably driven by the motor; an intermediate portion that movably supports the drill unit; a magnetic base coupled to the intermediate portion and configured to be selectively secured to a workpiece by magnetic force; A magnetic drilling machine equipped with an acceleration sensor or an angular velocity sensor.

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