Work machine

Abstract

Provided is a work machine capable of appropriately detecting a state in which a work machine main body swings. A working machine 1 is provided with a microcomputer 29 for controlling the driving of a motor 6. When the centrifugal force direction acceleration applied to the acceleration sensor (24) exceeds a centrifugal force direction acceleration threshold value, the microcomputer (29) reduces the number of revolutions of the motor (6) or stops the motor (6). The microcomputer (29) sets the condition that the load current of the motor (6) exceeds the current threshold (not in the no-load state) as the condition required for the operation of the swing suppression function.

Description

Technical Field

[0001] The invention relates to an operating machine such as a hammer drill. Background Art

[0002] Patent document 1 below discloses a working machine having the following function: when a rotating top tool is caught by a workpiece and the working machine body is swung, the motor is stopped. The working machine includes an acceleration sensor for detecting the sway of the working machine body, and when the acceleration in the left-right direction detected by the acceleration sensor exceeds a threshold value, the driving of the motor is stopped.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-150897 Summary of the invention

[0006] Problems to be solved by the invention

[0007] The acceleration in the left-right direction is the largest at the moment when the working machine body starts to sway, and tends to decrease with the passage of time. Therefore, when using the acceleration in the left-right direction to detect the swaying of the working machine body, when a short time has passed since the working machine body started to sway, it is difficult to judge whether the working machine body is not swaying or swaying at a constant speed. In addition, when the swaying speed increases slowly, it is difficult to judge whether the working machine body is swaying. In order to detect swaying, the swaying speed can also be calculated, but it is necessary to calculate the integral of the acceleration in the left-right direction, and the error is likely to become large.

[0008] An object of the present invention is to provide a working machine capable of appropriately detecting a state in which a working machine body is swaying.

[0009] Technical means of solving problems

[0010] One embodiment of the present invention is a working machine. The working machine includes: a motor; a top tool that rotates around a rotation axis by a driving force of the motor; a housing that supports the motor and the top tool; a control unit that controls the driving of the motor; and a detection unit that is supported by the housing and can detect the acceleration generated by itself, and the control unit controls the driving of the motor based on the radial acceleration generated in the radial direction around the rotation axis relative to the detection unit.

[0011] The present invention can be expressed as "electric working machine", "electric tool", "electric equipment" or the like, and items expressed in this way are also effective as embodiments of the present invention.

[0012] Effects of the Invention

[0013] According to the present invention, it is possible to provide a working machine capable of appropriately detecting a state in which a working machine body is swaying. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] [ Figure 1 ] is a right side sectional view of the working machine 1 according to an embodiment of the present invention.

[0015] [ Figure 2 ] is a circuit block diagram of the working machine 1.

[0016] [ Figure 3 ] (A) is a schematic diagram showing an example of a situation when the working machine 1 is working. (B) is a schematic diagram showing a situation when the working machine 1 is working as viewed from the concrete side. Figure 3 (A) is a schematic diagram of the working machine 1 in the state.

[0017] [ Figure 4 ] is a time diagram of the load current of the motor 6, the angle of the working machine body, the acceleration detection value in the X-axis direction obtained by the acceleration sensor 24, and the acceleration detection value in the Z-axis direction obtained by the acceleration sensor 24 when the working machine 1 is in high-speed mode and in normal cutting, that is, when the top tool 19 is not locked.

[0018] [ Figure 5 ] is a time diagram of the load current of the motor 6, the angle of the working machine body, the acceleration detection value in the X-axis direction obtained by the acceleration sensor 24, and the acceleration detection value in the Z-axis direction obtained by the acceleration sensor 24 when the working machine 1 is in high-speed mode, the top tool 19 is locked midway, and the swing suppression function is not operated.

[0019] [ Figure 6 ] is a time diagram of the load current of the motor 6, the angle of the working machine body, the acceleration detection value in the X-axis direction obtained by the acceleration sensor 24, and the acceleration detection value in the Z-axis direction obtained by the acceleration sensor 24 when the working machine 1 is in low-speed mode and in normal cutting, that is, when the top tool 19 is not locked.

[0020] [ Figure 7 ] is a time diagram of the load current of the motor 6, the angle of the working machine body, the acceleration detection value in the X-axis direction obtained by the acceleration sensor 24, and the acceleration detection value in the Z-axis direction obtained by the acceleration sensor 24 when the working machine 1 is in low speed mode, the top tool 19 is locked midway, and the swing suppression function is not operated.

[0021] [ Figure 8 ] is a control flow chart of the working machine 1. DETAILED DESCRIPTION

[0022] Figure 11 is a right side cross-sectional view of the working machine 1 according to the embodiment of the present invention. Figure 1 , define mutually orthogonal front and rear, up and down directions of the working machine 1. In addition, the direction perpendicular to the front and rear direction and the up and down direction is defined as the left and right direction. The front and rear direction is a direction parallel to the axial direction of the top tool 19. The up and down direction is a direction parallel to the axial direction of the output shaft 6a of the motor 6. The left and right direction is defined based on the operator observing the front.

[0023] The working machine 1 is a drilling tool, specifically a hammer drill. The working machine 1 can perform chiseling, drilling, and crushing operations on a target material (cutting material) such as concrete or stone by applying a rotational force and / or a striking force to a top tool 19. The working machine 1 includes a main body 2 and a dust collecting unit 3. The main body 2 has a main body shell 4. The dust collecting unit 3 can be detachably mounted on the main body shell 4.

[0024] The main body shell 4 is composed of a main body 4a, and a handle 4b. The main body 4a accommodates and holds the motor 6, the speed reduction mechanism 7, the intermediate shaft 8, the tool holding part 12, the reciprocating bearing 13, the cylinder 14, the main base plate 20, etc. The handle 4b is connected to the main body 4a via a vibration-proof mechanism so as to be relatively movably connected. A battery pack 10 as a power source is detachably connected to the rear lower part of the handle 4b. A trigger switch 9 is provided on the handle 4b for the operator to instruct the drive and stop of the motor 6. In addition, an operating panel 23 is provided on the main body 4a for the operator to switch the rotation mode of the motor 6 between the high-speed mode and the low-speed mode. The structure of the rotation striking mechanism (power transmission mechanism) that uses the rotation of the motor 6 to rotate and / or strike the top tool 19 is well known, so the following is limited to a simple description.

[0025] The motor 6 is a brushless electric motor. The rotation of the output shaft 6a of the motor 6 is decelerated by the speed reduction mechanism 7 located above the motor 6 and the rotation direction is changed by 90 degrees, and then the rotation is transmitted to the intermediate shaft 8. The axial direction of the intermediate shaft 8 is parallel to the front-rear direction. The first clutch mechanism 11a switches whether the rotation of the intermediate shaft 8 is transmitted to the reciprocating bearing 13. The second clutch mechanism 11b switches whether the rotation of the intermediate shaft 8 is transmitted to the cylinder 14. The transmission and interruption of the rotation based on the first clutch mechanism 11a and the second clutch mechanism 11b can be switched by the operator through a change lever (not shown).

[0026] The working machine 1 has three operation modes: a striking mode, a rotating striking mode, and a rotating mode. The operation mode is determined by the operation of the shift lever. In the striking mode, the rotation transmission based on the first clutch mechanism 11a is effective, and the rotation transmission based on the second clutch mechanism 11b is invalid. In the rotating striking mode, the rotation transmission of both the first clutch mechanism 11a and the second clutch mechanism 11b is effective. In the rotating mode, the rotation transmission based on the first clutch mechanism 11a is invalid, and the rotation transmission based on the second clutch mechanism 11b is effective.

[0027] A piston 15 is provided in the cylinder 14. In the striking mode or the rotary striking mode, the reciprocating bearing 13 converts the rotation of the intermediate shaft 8 into reciprocating movement in the front-rear direction and transmits it to the piston 15. An air chamber 16 and a striker (striking member) 17 are provided in the piston 15 in order from the rear. A second hammer (intermediate member) 18 is provided in front of the striker 17.

[0028] The air in the air chamber 16 is compressed by the forward movement of the piston 15, and the pressure (positive pressure) of the compressed air moves the striker 17 forward. The striker 17 moving forward strikes the second hammer 18, and the second hammer 18 moving forward due to the striking force strikes the top tool 19.

[0029] The air in the air chamber 16 expands due to the rearward movement of the piston 15, and the striker 17 moves rearward by the pressure (negative pressure) of the expanded air. In this way, the striker 17 is reciprocated back and forth by the change (compression / expansion) of the air pressure in the air chamber 16 caused by the reciprocating movement of the piston 15, and the striker 17 hits the second hammer 18, and the second hammer 18 hits the top tool 19.

[0030] In the rotary striking mode or the rotary mode, the air cylinder 14 is driven to rotate via the intermediate shaft 8. The tool holding portion 12 provided in front of the air cylinder 14 rotates together with the air cylinder 14. The top tool 19 is held by the tool holding portion 12 and extends forward from the main body housing 4, and rotates together with the tool holding portion 12. The rotation axis of the top tool 19 is coaxial with the rotation axis of the air cylinder 14, and is hereinafter referred to as the "rotation axis". The top tool 19 receives the driving force of the motor 6 and rotates around the rotation axis.

[0031] The main substrate 20 is supported by the main body casing 4 below the motor 6 in a posture perpendicular to the up-down direction.

[0032] Figure 2: is a circuit block diagram of the working machine 1. The working machine 1 includes a current detection circuit 22, an acceleration sensor 24 as a detection unit, a voltage detection circuit 25, an inverter circuit 26, a rotor position detection circuit 27, a temperature detection circuit 28, and a microcomputer 29 (microcomputer or microcontroller) as a control unit on a main substrate 20. That is, the acceleration sensor 24 is provided in the main body 4a of the main body case 4. The acceleration sensor 24 may also be provided in the handle 4b.

[0033] The current detection circuit 22 detects the load current (hereinafter referred to as "load current") flowing in the motor 6, and sends it to the microcomputer 29. The current detection circuit 22 and the acceleration sensor 24 together constitute a detection unit. The acceleration sensor 24 can detect the acceleration generated by itself. The voltage detection circuit 25 detects the output voltage of the battery pack 10 and sends it to the microcomputer 29. The inverter circuit 26 includes, for example, a switching element such as a field-effect transistor (FET) or an insulated gate bipolar transistor (IGBT) connected via a three-phase bridge, and is a drive circuit that supplies a drive current to the motor 6.

[0034] The rotor position detection circuit 27 detects the rotor rotation position using the output signal of a magnetic sensor 30 such as a Hall integrated circuit (IC) that outputs a signal corresponding to the rotation position (rotor rotation position) of the motor 6, and transmits the signal to the microcomputer 29. The temperature detection circuit 28 detects the temperature of the inverter circuit 26 and transmits the signal to the microcomputer 29.

[0035] The microcomputer 29 controls the inverter circuit 26, for example, by pulse-width modulation (PWM) control, according to the mode set by the operation panel 23 and the operation of the trigger switch 9, and controls the driving of the motor 6. The microcomputer 29 controls the lighting of the light emitting diode (LED) 21 that illuminates the work area or the panel LED provided on the operation panel 23.

[0036] Figure 3 (A) is a schematic diagram showing an example of a situation during operation of the working machine 1 . Figure 3 (B) Viewed from the concrete side Figure 3 (A) is a schematic diagram of the working machine 1. The acceleration sensor 24 is a triaxial acceleration sensor here. Figure 3The XYZ axes shown in (A) and (B) are three orthogonal axes corresponding to the detection axes of the acceleration sensor 24. The X axis is parallel to the left-right direction, the +X direction corresponds to the left direction, and the -X direction corresponds to the right direction. The Y axis is parallel to the front-back direction, the +Y direction corresponds to the front direction, and the -Y direction corresponds to the rear direction. The Z axis is parallel to the up-down direction, the +Z direction corresponds to the down direction, and the -Z direction corresponds to the up direction.

[0037] During the operation performed by the work machine 1, the tip tool 19 may get caught by the object material, such as concrete 50. In this case, the tip tool 19 is locked, and the work machine body (the entire work machine 1 except the tip tool 19) is locked around the tip tool 19 in the locked state. Figure 3 (B) Swing in the direction of rotation shown.

[0038] The work machine 1 has a function of reducing the number of revolutions of the motor 6 or stopping the motor 6 when the work machine body is detected to be swaying (also referred to as a "sway suppression function" in this specification). When the sway suppression function is in operation, it is preferable to stop the motor 6 in terms of the effect of suppressing the swaying of the work machine body, but a certain suppression effect can also be obtained by reducing the number of revolutions of the motor 6 without stopping the motor 6.

[0039] The microcomputer 29 detects whether the working machine body is swaying based on the acceleration detection value in the Z-axis direction of the acceleration sensor 24, that is, the radial acceleration (acceleration in the centrifugal force direction) generated in the radial direction with the rotation axis as the center relative to the acceleration sensor 24. The radial acceleration (acceleration in the centrifugal force direction) is the acceleration generated in the direction (+Z direction) away from the rotation axis along the imaginary line (Z-axis line) connecting the acceleration sensor 24 and the rotation axis (or its extension line).

[0040] As a configuration example of the hunting suppression function of the present embodiment, when the centrifugal force direction acceleration exceeds the centrifugal force direction acceleration threshold value as the first threshold value, the microcomputer 29 reduces the number of revolutions of the motor 6 or stops the motor 6 .

[0041] Alternatively, when the centrifugal acceleration exceeds the centrifugal acceleration threshold as the first threshold and the load current exceeds the current threshold as the second threshold, the microcomputer 29 reduces the number of revolutions of the motor 6 or stops the motor 6. The current threshold is set so that the load current exceeds the current threshold unless the top tool 19 is in a no-load state without contact with the workpiece.

[0042] Alternatively, when the centrifugal force direction acceleration exceeds the centrifugal force direction acceleration threshold value as the first threshold value, and the acceleration detection value in the X-axis direction of the acceleration sensor 24, that is, the circumferential acceleration (left-right acceleration) generated in the circumferential direction with respect to the acceleration sensor 24 centered on the rotation axis exceeds the left-right acceleration threshold value as the third threshold value, the microcomputer 29 reduces the number of revolutions of the motor 6 or stops the motor 6. The left-right acceleration threshold value is a threshold value for confirming the generation of the acceleration in the left direction with respect to the acceleration sensor 24, that is, the acceleration in the swing direction of the working machine body due to the reaction when the motor 6 attempts to rotate the top tool 19 in the locked state.

[0043] Furthermore, the so-called "exceeding the threshold value" specifically means "maintaining the state of exceeding the threshold value for a predetermined time". For example, even if the acceleration in the direction of centrifugal force exceeds the first threshold value instantaneously and falls below the first threshold value again within the predetermined time, it is determined that the first threshold value has not been exceeded. Thus, although there is actually no swing, the phenomenon that the value exceeds the threshold value instantaneously due to vibration or the like can be ignored as noise. Of course, it is also possible to ignore the time and determine that "exceeding the threshold value" when the value exceeds the threshold value even for a very short time.

[0044] The microcomputer 29 sets the centrifugal force direction acceleration threshold, the current threshold, and the left-right direction acceleration threshold to different values ​​according to the high-speed mode and the low-speed mode (set in a manner that they become higher in the high-speed mode). For example, the microcomputer 29 sets the current threshold to 8.0 A, the left-right direction acceleration threshold to 1.0 G, and the centrifugal force direction acceleration threshold to 2.0 G in the high-speed mode, and sets the current threshold to 4.0 A, the left-right direction acceleration threshold to 0.5 G, and the centrifugal force direction acceleration threshold to 0.75 G in the low-speed mode.

[0045] Figure 4 The following is a time chart of the load current, the angle of the work machine body, the acceleration detection value in the X-axis direction (lateral acceleration) obtained by the acceleration sensor 24, and the acceleration detection value in the Z-axis direction (centrifugal force direction acceleration) obtained by the acceleration sensor 24 when the work machine 1 is in high-speed mode and in normal cutting, that is, when the top tool 19 is not locked. In addition, Figure 4 to Figure 7 The time diagrams all represent the case where the top tool 19 rotates clockwise. When the top tool 19 rotates counterclockwise, the positive and negative values ​​of the left and right acceleration thresholds are opposite.

[0046] exist Figure 4At time t0, the trigger switch 9 is turned on. The load current temporarily increases from the turning on of the trigger switch 9 (around 20 ms) to 200 ms, that is, when the motor 6 is started, and then stabilizes at around 10 A. The angle of the working machine body is roughly constant, although it varies by about ±1° due to vibrations during operation. The left-right acceleration fluctuates within a range of about ±3 G (G is the acceleration of gravity) due to vibrations during operation, but is roughly zero on average. The centrifugal acceleration fluctuates within a range of about ±1 G due to vibrations during operation, but does not exceed the centrifugal acceleration threshold (2.0 G) and is roughly zero on average.

[0047] Figure 5 This is a time diagram of the load current, the angle of the work machine body, the acceleration detection value in the X-axis direction (left-right acceleration) obtained by the acceleration sensor 24, and the acceleration detection value in the Z-axis direction (centrifugal force direction acceleration) obtained by the acceleration sensor 24 when the work machine 1 is in high-speed mode, the top tool 19 is locked midway, and the swing suppression function is not operated.

[0048] exist Figure 5 At time t0, the trigger switch 9 is turned on, at time t1 (around 40 ms), the top tool 19 is fixed to the object material, at time t3 (around 150 ms), the operator starts pressing the work machine body, and at time t5 (around 270 ms), the work machine body stops when the swing exceeds 40° slightly.

[0049] The left-right acceleration instantly jumps to about 8 G just after time t1 and decreases to near 0, then increases to about 5 G, then decreases, and becomes 0 at time t3. The left-right acceleration becomes - after time t3 due to the force of the operator trying to stop the working machine body, and becomes 0 at time t5.

[0050] The centrifugal acceleration starts to rise from time t1, and at time t5, just before the operator starts to press the work machine body, that is, when the swing angular velocity of the work machine body centered on the top tool 19 reaches the maximum, it reaches a peak value slightly exceeding 2.5 G (a peak value exceeding the centrifugal acceleration threshold value). The centrifugal acceleration decreases after time t3 in accordance with the operator's deceleration of the swing speed of the work machine body, and becomes 0 at time t5.

[0051] Figure 6It is a time diagram of the load current, the angle of the working machine body, the acceleration detection value in the X-axis direction (left-right acceleration) obtained by the acceleration sensor 24, and the acceleration detection value in the Z-axis direction (centrifugal force direction acceleration) obtained by the acceleration sensor 24 when the working machine 1 is in low-speed mode and during normal cutting, that is, when the top tool 19 is not locked.

[0052] exist Figure 6 , at time t0, the trigger switch 9 is turned on. The load current temporarily increases from the turning on of the trigger switch 9 (around 20 ms) to 320 ms, that is, when the motor 6 is started, and then stabilizes at a certain value. Although the angle of the working machine body has a touch of about ±1° due to vibrations during operation, etc., it is roughly constant. Although the left and right accelerations vibrate within the range of about ±1.5 G due to vibrations during operation, etc., they are roughly zero on average. Although the acceleration in the centrifugal force direction vibrates within the range of about ±0.7 G due to vibrations during operation, etc., it does not exceed the centrifugal force direction acceleration threshold (0.75 G) and is roughly zero on average.

[0053] Figure 7 This is a time diagram of the load current, the angle of the work machine body, the acceleration detection value in the X-axis direction (left-right acceleration) obtained by the acceleration sensor 24, and the acceleration detection value in the Z-axis direction (centrifugal force direction acceleration) obtained by the acceleration sensor 24 when the work machine 1 is in low-speed mode, the top tool 19 is locked midway, and the swing suppression function is not operated.

[0054] exist Figure 7 At 0 ms, the trigger switch 9 is turned on, at time t7 (around 40 ms), the top tool 19 is fixed to the object material, at time t9 (around 280 ms), the operator starts pressing the work machine body, and at time t11 (around 400 ms), the work machine body stops when the swing exceeds 35°.

[0055] The left-right acceleration instantly jumps to about 4 G just after time t7 and drops to near 0, then slowly rises from 0 as an average value while vibrating, and returns to 0 at time t9. The left-right acceleration becomes - after time t9 due to the force of the operator trying to stop the main body of the work machine, and becomes 0 at time t11.

[0056] The centrifugal acceleration starts to rise from time t7, and at time t9, just before the operator starts to press the work machine body, that is, when the swing angular velocity of the work machine body centered on the top tool 19 reaches the maximum, it reaches a peak value slightly exceeding 0.8 G (a peak value exceeding the centrifugal acceleration threshold value). After time t9, the centrifugal acceleration decreases in accordance with the operator's deceleration of the swing speed of the work machine body, and becomes 0 at time t11.

[0057] Figure 8 This is a control flow chart of the working machine 1. The microcomputer 29 obtains acceleration data, that is, the acceleration detection value obtained by the acceleration sensor 24 (S1). The microcomputer 29 substitutes the acceleration detection value in the Z-axis direction (centrifugal force direction acceleration) contained in the acceleration data into the acceleration initial value (S3). When the motor 6 is not in the startup state (No in S5), the microcomputer 29 returns to S1. The centrifugal force direction acceleration just after the motor 6 is started is set in the acceleration initial value. In addition, the acceleration initial value can also be set to zero.

[0058] When the motor 6 is in the activated state (Yes in S5 ), the microcomputer 29 acquires acceleration data ( S7 ) and substitutes a value obtained by subtracting the acceleration initial value set in S3 from the centrifugal force direction acceleration included in the acceleration data into the determination value.

[0059] If the determination value does not exceed the centrifugal acceleration threshold value (No in S11 ), the microcomputer 29 returns to S7 . If the determination value exceeds the centrifugal acceleration threshold value (Yes in S11 ), the microcomputer 29 checks whether the load current exceeds the current threshold value ( S13 ).

[0060] When the load current does not exceed the current threshold value (No in S13 ), the microcomputer 29 returns to S7 . This can suppress the operation of the swing suppression function when the operator moves the working machine body when the motor 6 is rotated in a no-load state.

[0061] When the load current exceeds the current threshold value (Yes in S13), the microcomputer 29 calculates the swing direction of the working machine body based on the acceleration detection value in the X-axis direction (left-right acceleration) included in the acceleration data, and confirms whether the swing direction is opposite to the rotation direction of the top tool (S15). More specifically, when the motor 6 rotates in the direction in which the top tool 19 rotates counterclockwise when viewed from the rear, it is confirmed whether the acceleration in the clockwise direction (i.e., the left acceleration) exceeds the threshold value. In addition, when the motor 6 rotates in the direction in which the top tool 19 rotates clockwise when viewed from the rear, it is confirmed whether the acceleration in the counterclockwise direction (i.e., the right acceleration) exceeds the threshold value.

[0062] The microcomputer 29 calculates the swing direction of the working machine body, and returns to S7 when the swing direction is not opposite to the rotation direction of the top tool (No in S15). This can prevent the swing suppression function from malfunctioning when the operator swings the working machine body in a direction different from the direction in which the acceleration is estimated to occur when the top tool 19 is locked, for example.

[0063] When the swing direction of the working machine body is opposite to the rotation direction of the tool tip (Yes in S15 ), the microcomputer 29 reduces the number of revolutions of the motor 6 or stops the motor 6 ( S17 ).

[0064] According to this embodiment, the following effects can be achieved.

[0065] (1) The microcomputer 29 controls the driving of the motor 6 based on the radial acceleration (centrifugal acceleration) generated in the radial direction with respect to the acceleration sensor 24 and centered on the rotation axis. Specifically, when the centrifugal acceleration exceeds the centrifugal acceleration threshold, the microcomputer 29 reduces the number of revolutions of the motor 6 or stops the motor 6. Therefore, the state of the swing of the working machine body can be appropriately detected, and the operation of the swing suppression function can be appropriately performed.

[0066] Here, as a comparison, a case where it is determined whether the working machine body is swaying by determining whether the left-right acceleration exceeds a threshold value is studied. The left-right acceleration shows a large value instantaneously when the top tool 19 is locked, but decreases thereafter. Therefore, it is difficult to distinguish the instantaneous large value of the left-right acceleration caused by the locking of the top tool 19 from the instantaneous large value caused by noise or instantaneous vibration. In addition, if you want to make a judgment after the instantaneous large value has passed, the left-right acceleration will decrease with the passage of time. Therefore, the more time passes, the more difficult it is to distinguish whether the working machine body is not swinging or the swinging speed is approximately constant. In the case of deriving the swinging speed of the working machine body based on the left-right acceleration, it is necessary to calculate the integration of the left-right acceleration, but since the error contained in the detection value of the left-right acceleration itself is also integrated, the error becomes larger.

[0067] In this regard, the acceleration in the direction of centrifugal force is a non-instantaneous large value when the top tool 19 is locked. Therefore, the large value of the acceleration in the direction of centrifugal force caused by the locking of the top tool 19 is easily distinguished from the instantaneous large value caused by noise or instantaneous vibration. In addition, since the rotational speed of the swinging of the working machine body increases with the passage of time, it is not difficult to distinguish whether the working machine body does not swing due to the passage of time or the swinging speed is approximately constant. In addition, the acceleration in the direction of centrifugal force is proportional to the square of the rotational speed of the swinging of the working machine body, and directly corresponds to the rotational speed of the swinging of the working machine body. Therefore, regardless of the integral calculation, the rotational speed of the swinging of the working machine body can be estimated based on the acceleration in the direction of centrifugal force, and the error is small. In this embodiment, by judging whether the working machine body is swinging based on the acceleration in the direction of centrifugal force, the state of the swinging of the working machine body can be appropriately detected.

[0068] (2) The microcomputer 29 sets the load current exceeding the current threshold (not in a no-load state) as a condition required for the operation of the swing suppression function. Therefore, when the motor 6 is rotated in a no-load state, the operation of the swing suppression function when the operator moves the working machine body can be suppressed.

[0069] (3) The microcomputer 29 sets the swing direction of the working machine body opposite to the rotation direction of the top tool as a condition required for the operation of the swing suppression function. Therefore, for example, when the top tool 19 is in a locked state, the operator swings the working machine body in a direction different from the direction in which the acceleration is estimated to occur, and the swing suppression function is prevented from erroneously operating.

[0070] Although the present invention has been described above by taking the embodiments as examples, various modifications can be made to the components and processing steps of the embodiments within the scope of the claims.

[0071] The working machine of the present invention is not limited to a hammer drill, but may be other types of working machines such as a screwdriver drill or a drill. The load current value, acceleration, time, various threshold values, etc., which are exemplified as specific numerical values ​​in the embodiments, do not limit the scope of the invention in any way and may be arbitrarily changed according to the required specifications.

[0072] Explanation of symbols

[0073] 1: Operating machine (hammer drill)

[0074] 2: Main body

[0075] 3: Dust collection unit

[0076] 4: Main body shell

[0077] 6: Motor (electric motor)

[0078] 6a: Output shaft

[0079] 7: Speed ​​reduction mechanism

[0080] 8: Intermediate shaft

[0081] 9: Trigger switch

[0082] 10: Battery Pack

[0083] 11a: First clutch mechanism

[0084] 11b: Second clutch mechanism

[0085] 12: Tool holding part

[0086] 13: Reciprocating bearings

[0087] 14: Cylinder

[0088] 15: Piston

[0089] 16: Air Chamber

[0090] 17: Impactor (striking piece)

[0091] 18: Second Hammer (Middleware)

[0092] 19: Top Tools

[0093] 20: Main base board

[0094] 21: Lighting LED

[0095] 22: Current detection circuit

[0096] 23: Operation panel

[0097] 24: Acceleration sensor

[0098] 25: Voltage detection circuit

[0099] 26: Inverter circuit

[0100] 27: Rotor position detection circuit

[0101] 28: Temperature detection circuit

[0102] 29: Microcomputer (control unit)

[0103] 30: Magnetic sensor

[0104] 50: Concrete (target material)

Claims

1. A working machine, comprising: motor; The top tool is rotated around the rotation axis by the driving force of the motor; a housing supporting the motor and the top tool; A control unit, controlling the driving of the motor; as well as The detection unit is supported by the housing and can detect the acceleration generated by itself. The control unit controls driving of the motor based on radial acceleration generated in a radial direction around the rotation axis with respect to the detection unit. 2 . The working machine according to claim 1 , wherein when the radial acceleration exceeds a first threshold value, the control portion reduces the number of revolutions of the motor. 3 . The working machine according to claim 1 , wherein when the radial acceleration exceeds a first threshold value, the control unit stops the motor.

4. The working machine according to claim 1, wherein the detection unit is also capable of detecting a load current of the motor. The control portion reduces the number of revolutions of the motor when the radial acceleration exceeds a first threshold and the load current exceeds a second threshold. 5 . The working machine according to claim 1 , wherein when the radial acceleration exceeds a first threshold value and the circumferential acceleration generated in a circumferential direction around the rotation axis with respect to the detection portion exceeds a third threshold value, the control portion reduces the number of revolutions of the motor. 6 . The working machine according to claim 1 , wherein the radial acceleration is an acceleration generated in a direction along an imaginary line connecting the detection unit and the rotation axis and in a direction away from the rotation axis.

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