Load device

Abstract

The present disclosure addresses the problem of providing a load device that is used for performing a tightening operation via an electric tool. A load device (1) comprises a placement part (3), an input part (4), and a load part (5). The placement part (3) has a recess and a through hole (321). An electric tool is placed in the recess. The electric tool has a tool housing that houses a motor, and an output shaft that protrudes from the tool housing. The output shaft is passed through the through hole (321). The placement part (3) restricts rotation of the tool housing when the electric tool is placed in the recess. The input part (4) is connected to the output shaft that has been passed through the through hole (321), and is supported so as to be rotatable in the direction of rotation of the output shaft. The load part (5) is connected to the input part (4), and increases a load when the input part (4) rotates, as the input part (4) rotates in the direction of rotation.

Description

Load device

[0001] The present disclosure generally relates to a load device, and more particularly to a load device used in a power tool.

[0002] Patent Document 1 discloses a diagnostic method for diagnosing a power tool unit. This diagnostic method has a storage step and a determination step. In the storage step, a physical quantity related to the power tool unit measured by the measurement unit is stored in the storage unit. In the determination step, based on the physical quantity stored in the storage unit, replacement information regarding whether the tip tool needs to be replaced is obtained.

[0003] Japanese Unexamined Patent Application Publication No. 2024 - 6727

[0004] By the way, it is desired to more easily perform a diagnosis for grasping the state of a power tool unit (power tool) as described in Patent Document 1.

[0005] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a load device used for performing a tightening operation by a power tool.

[0006] A load device according to an aspect of the present disclosure includes an installation part, an input part, and a load part. The installation part has a concave part and a through hole. The power tool is installed in the concave part. The power tool has a tool housing that houses a motor and an output shaft that protrudes from the tool housing. The output shaft passes through the through hole. The installation part restricts the rotation of the tool housing when the power tool is installed in the concave part. The input part is connected to the output shaft that has passed through the through hole and is rotatably supported in the rotation direction of the output shaft. The load part is connected to the input part and increases the load when the input part rotates as the input part rotates in the rotation direction.

[0007] Figure 1 is a block diagram of a load system according to one embodiment. Figure 2 is a perspective view showing the external appearance of the load system in a power tool. Figure 3 is a perspective view showing the external appearance of the load device in the load system. Figure 4 is a cross-sectional view taken along line A-A in Figure 3. Figure 5 is a plan view of the load device. Figure 6 is an exploded perspective view of the main part of the load device. Figure 7 is a flowchart showing the operation of the load system. Figure 8 is a block diagram of the load system according to modification 1 of the above. Figure 9 is a cross-sectional view of the load device according to modification 2 of the above. Figure 10 is a schematic diagram showing the main part of the load device according to modification 3 of the above. Figure 11 is a schematic diagram showing the main part of the load device according to modification 4 of the above. Figure 12 is a schematic diagram showing the arrangement of multiple disc springs in a load device according to another modification of the above.

[0008] Preferred embodiments of this disclosure will be described in detail below with reference to the drawings. Common elements in the embodiments described below are denoted by the same reference numerals, and redundant descriptions of common elements may be omitted. The embodiments and modifications described below represent only a portion of the various embodiments of this disclosure. Furthermore, the embodiments and modifications described below can be modified in various ways depending on the design, etc., as long as the objectives of this disclosure are achieved. It is also possible to combine the configurations of the embodiments and modifications as appropriate.

[0009] The figures described in this disclosure are schematic diagrams, and the ratios of the size and thickness of each component in each figure do not necessarily reflect the actual dimensional ratios. Furthermore, the arrows indicating directions in the drawings are examples only and are not intended to specify the direction of use for the load device 1 or the power tool 7. Also, the arrows indicating directions in the drawings are for illustrative purposes only and do not represent actual structures.

[0010] (1) Overview First, an overview of the load device 1 of the load system 100 according to this embodiment will be described with reference to Figures 1 to 5.

[0011] As shown in Figure 1, the load system 100 of this embodiment comprises a load device 1 and a power tool 7.

[0012] The power tool 7 includes a motor 71, a tool housing 700 (see Figure 2) that houses the motor 71, and an output shaft 73 that protrudes from the tool housing 700.

[0013] As shown in Figure 4, the load device 1 comprises an installation section 3, an input section 4, and a load section 5.

[0014] The mounting section 3 has a first recess 32 (recess) in which the power tool 7 is installed, and a through hole 321 through which the output shaft 73 of the power tool 7 passes. The mounting section 3 restricts the rotation of the tool housing 700 when the power tool 7 is installed in the first recess 32.

[0015] The input unit 4 is mechanically connected to the output shaft 73, which passes through the through hole 321 of the mounting unit 3. The input unit 4 is rotatably supported in the rotational direction D3 (see Figure 5) of the output shaft 73.

[0016] The load unit 5 is mechanically connected to the input unit 4. The load unit 5 increases the load on the input unit 4 as it rotates in the rotational direction D3.

[0017] According to the load device 1 of this embodiment, a tightening operation can be performed using the load device 1 with the power tool 7. This makes it possible to perform a tightening operation on the load device 1 for diagnostic purposes, such as determining the condition of the power tool 7, without using a workpiece that is the target of work on an assembly line, thus making it easier to diagnose the condition of the power tool 7.

[0018] (2) Details The detailed configuration of the load system 100 according to this embodiment will be described below with reference to Figures 1 to 6.

[0019] (2.1) Configuration of the load system The load system 100 of this embodiment is used, for example, in an assembly line in a factory where workpieces are assembled. More specifically, the load system 100 is used to diagnose the condition of the power tools 7 used in the assembly line.

[0020] As shown in Figure 1, the load system 100 according to this embodiment comprises a load device 1 and a power tool 7.

[0021] (2.2) Configuration of the power tool The power tool 7 comprises a motor 71, an impact mechanism 72, an output shaft 73, a motor rotation measurement unit 74, a memory unit 75, a display unit 76, a processing unit 77, an inverter circuit unit 78, and a communication unit 79.

[0022] Motor 71 is, for example, a brushless motor. Motor 71 has a motor shaft and converts the power supplied from the power supply 710 (see Figure 2) into rotational driving force for the motor shaft.

[0023] The impact mechanism 72 generates a pulsed rotational impact force from the power of the motor 71. The impact mechanism 72 comprises a drive shaft, a reduction gear, a hammer, an anvil, and a spring. The drive shaft is positioned between the motor shaft and the output shaft 73 of the motor 71.

[0024] The reduction gear reduces the rotational driving force of the motor shaft of the motor 71 by a predetermined reduction ratio and transmits it to the drive shaft.

[0025] The hammer moves relative to the anvil and, powered by the motor 71, applies rotational impact to the anvil. The hammer is movable in the axial direction of the drive shaft and is rotatable relative to the drive shaft. As the hammer moves toward or away from the anvil along the axial direction of the drive shaft, the hammer rotates relative to the drive shaft. The hammer is also rotatable relative to the spring.

[0026] The anvil is formed integrally with the output shaft 73. The anvil faces the hammer in the axial direction of the drive shaft. When the impact mechanism 72 is not performing a striking motion, the drive shaft, hammer, and anvil rotate together as a single unit.

[0027] The spring is sandwiched between the gearbox and the hammer. The spring is, for example, a conical spring. The spring applies a force to the hammer in the direction toward the output shaft 73, along the axial direction of the drive shaft.

[0028] In the following, when the hammer moves toward the anvil in the axial direction of the drive shaft, it will be referred to as "the hammer moving forward." Conversely, when the hammer moves toward the anvil in the axial direction of the drive shaft, it will be referred to as "the hammer moving backward."

[0029] In the impact mechanism 72, the striking action begins when the load torque exceeds a predetermined value. That is, as the load torque increases, the component of the force generated between the hammer and the anvil that pushes the hammer backward also increases. When the load torque exceeds a predetermined value, the hammer moves backward while compressing the spring. Then, the hammer rotates as it moves backward. After that, the hammer moves forward due to the restorative force from the spring. Then, the hammer delivers a rotational blow to the anvil approximately every half rotation of the drive shaft.

[0030] In this way, the impact mechanism 72 repeatedly applies rotational impact to the anvil with a hammer. The torque generated by this rotational impact allows for a stronger tightening of fastening members such as screws, bolts, or nuts.

[0031] Furthermore, if the impact mechanism 72 repeatedly performs impact operations, at least one of the hammer and the anvil may wear down, and this wear may reduce the tightening torque.

[0032] An end tool, such as a socket, is attached to the output shaft 73. The output shaft 73 transmits the rotational driving force transmitted from the drive shaft to the end tool. This causes the end tool to rotate. As the end tool rotates while in contact with the fastening member, it becomes possible to tighten or loosen the fastening member. The output shaft 73 also transmits the rotational impact force (impact force) transmitted from the impact mechanism 72 to the end tool.

[0033] The motor rotation measurement unit 74 measures the rotation angle of the motor 71. For example, a photoelectric encoder or a magnetic encoder can be used as the motor rotation measurement unit 74.

[0034] The communication unit 79 includes an interface configured to communicate with other devices. In this embodiment, the communication unit 79 includes an interface capable of wired communication with the load device 1 installed in the installation unit 3.

[0035] The memory unit 75 is composed of a device selected from ROM (Read Only Memory), RAM (Random Access Memory), or EEPROM (Electrically Erasable Programmable Read Only Memory), etc. The memory unit 75 stores information used to diagnose wear and deterioration of the impact mechanism 72 (i.e., wear and deterioration of the hammer and anvil).

[0036] The display unit 76 displays the results of the wear and deterioration diagnosis of the impact mechanism 72. The display unit 76 has, for example, an LED (Light Emitting Diode) and displays the results of the deterioration diagnosis performed by the processing unit 77.

[0037] The processing unit 77 includes a computer system having one or more processors and memory. At least some of the functions of the processing unit 77 are realized when the processor of the computer system executes a program recorded in the memory of the computer system. The program may be recorded in memory, provided via a telecommunication line such as the Internet, or provided on a non-temporary recording medium such as a memory card.

[0038] The processing unit 77 includes a current measurement unit 770, a first control unit 771, a second control unit 772, a deterioration diagnosis unit 773, a notification unit 774, and a prediction unit 775. The power tool 7 also includes an inverter circuit unit 78 and a plurality (two in Figure 1) of current sensors SE1 and SE2.

[0039] Each of the multiple current sensors SE1 and SE2 includes, for example, a Hall element current sensor or a shunt resistor element. The multiple current sensors SE1 and SE2 measure the current supplied from the power supply 710 to the motor 71 via the inverter circuit 78. Here, the motor 71 is supplied with three-phase current (U-phase current, V-phase current, and W-phase current), and the multiple current sensors SE1 and SE2 measure the current of at least two phases. In this embodiment, current sensor SE1 measures the U-phase current and outputs a first current measurement value, and current sensor SE2 measures the V-phase current and outputs a second current measurement value.

[0040] The current measurement unit 770 measures the q-axis current supplied to the motor 71. Furthermore, the current measurement unit 770 measures the d-axis current supplied to the motor 71. The current measurement unit 770 measures the d-axis current corresponding to the magnetic field component and the q-axis current corresponding to the torque component by performing a coordinate transformation on the first and second current measurements taken by the multiple current sensors SE1 and SE2 based on the rotation angle of the motor 71 measured by the motor rotation measurement unit 74.

[0041] The second control unit 772 calculates the difference between the d-axis current command value and the d-axis current value measured by the current measurement unit 770. Based on the calculated difference, the second control unit 772 determines the magnitude of the d-axis current of the motor 71.

[0042] As shown in Figure 1, the first control unit 771 includes a first current control unit 771a and a second current control unit 771b.

[0043] The first current control unit 771a calculates the angular velocity (angular velocity of the motor shaft), which is the rotational speed of the motor 71, by differentiating the rotation angle of the motor 71 measured by the motor rotation measurement unit 74 with respect to time. The first current control unit 771a calculates the difference between the rotational speed command value obtained according to the amount of pull of the trigger 709 and the calculated rotational speed of the motor 71. Based on the calculated difference, the first current control unit 771a determines a q-axis current command value to instruct the motor 71 to output a q-axis current value. The first current control unit 771a determines the q-axis current command value such that the difference or deviation between the rotational speed command value and the rotational speed of the motor 71 is small.

[0044] The second current control unit 771b calculates the difference between the q-axis current command value obtained by the first current control unit 771a and the value of the q-axis current measured by the current measurement unit 770. The second current control unit 771b obtains the duty ratio related to the switching of the inverter circuit unit 78 based on the calculated difference and the value obtained by inversely transforming the magnitude of the d-axis current obtained by the second control unit 772. The inverter circuit unit 78 performs a switching operation based on the duty ratio obtained by the second current control unit 771b.

[0045] The deterioration diagnosis unit 773 diagnoses the progress state of the wear deterioration of the impact mechanism 72 using the q-axis current measured by the current measurement unit 770. The deterioration diagnosis unit 773 determines that the wear deterioration of the impact mechanism 72 is progressing when the q-axis current measured by the current measurement unit 770 has a downward trend.

[0046] More specifically, the deterioration diagnosis unit 773 diagnoses the progress state of the wear deterioration of the impact mechanism 72 based on at least one value among the instantaneous torque value, angular momentum, instantaneous power, work amount, and q-axis current average value obtained from the q-axis current measured by the current measurement unit 770. The deterioration diagnosis unit 773 determines that the q-axis current has a downward trend when at least one value among the instantaneous torque value, angular momentum, instantaneous power, work amount, and q-axis current average value obtained from the q-axis current measured by the current measurement unit 770 has a downward trend. Further, the deterioration diagnosis unit 773 determines that there is a downward trend when the value obtained by dividing at least one value among the instantaneous torque value, angular momentum, instantaneous power, work amount, and q-axis current average value obtained from the q-axis current measured by the current measurement unit 770 by the reference value is less than or equal to a predetermined value.

[0047] For example, the deterioration diagnosis unit 773 calculates the instantaneous torque value τ(t) obtained from the q-axis current measured by the current measurement unit 770 using the following formula (1).

[0048]

[0049] Here, Pn is the number of pole pairs, φa is the flux linkage, iq(t) is the q-axis current, id(t) is the d-axis current, Ld is the d-axis inductance, and Lq is the q-axis inductance. The number of pole pairs "Pn", the flux linkage "φa", the d-axis inductance "Ld", and the q-axis inductance "Lq" are pre-stored in the memory unit 75.

[0050] The deterioration diagnosis unit 773 diagnoses the wear and deterioration of the impact mechanism 72 based on the instantaneous torque value τ(t) obtained from the q-axis current measured by the current measurement unit 770. The deterioration diagnosis unit 773 determines that the q-axis current is decreasing if the instantaneous torque value τ(t) is decreasing. The deterioration diagnosis unit 773 determines that the instantaneous torque value τ(t) is decreasing if the decrease in the instantaneous torque value τ(t) continues for a predetermined period of time. Furthermore, the deterioration diagnosis unit 773 determines that the instantaneous torque value τ(t) is decreasing if the value obtained by dividing the instantaneous torque value τ(t) by a reference value for the instantaneous torque value τ(t) is less than or equal to a predetermined value. The reference value for the instantaneous torque value τ(t) may be stored in the storage unit 75 at the time of manufacture or shipment of the power tool 7, or the instantaneous torque value calculated when the power tool 7 is first operated after purchase may be stored in the storage unit 75 as the reference value for the instantaneous torque value τ(t).

[0051] Furthermore, the deterioration diagnosis unit 773 calculates angular momentum by integrating the instantaneous torque value τ(t) over time. Based on the angular momentum obtained from the q-axis current measured by the current measurement unit 770, the deterioration diagnosis unit 773 diagnoses the progress of wear deterioration of the impact mechanism 72. The deterioration diagnosis unit 773 determines that the q-axis current is decreasing when the angular momentum is decreasing. The deterioration diagnosis unit 773 determines that the angular momentum is decreasing when the decrease in angular momentum continues for a predetermined period of time. In addition, the deterioration diagnosis unit 773 determines that the angular momentum is decreasing when the value obtained by dividing the angular momentum by a reference value for angular momentum is less than or equal to a predetermined value. The reference value for angular momentum may be stored in the memory unit 75 at the time of manufacture or shipment of the power tool 7, or the angular momentum calculated when the power tool 7 is first operated after purchase may be stored in the memory unit 75 as the reference value for angular momentum.

[0052] Furthermore, the deterioration diagnosis unit 773 calculates the instantaneous power (τ(t) × ω(t)) obtained from the q-axis current measured by the current measurement unit 770 using the following equation (2) which uses the instantaneous torque value τ(t) and the rotational speed ω(t) of the motor 71.

[0053]

[0054] The deterioration diagnosis unit 773 diagnoses the wear and deterioration of the impact mechanism 72 based on the instantaneous power obtained from the q-axis current measured by the current measurement unit 770. The deterioration diagnosis unit 773 determines that the q-axis current is decreasing if the instantaneous power is decreasing. The deterioration diagnosis unit 773 determines that the instantaneous power is decreasing if the decrease in instantaneous power continues for a predetermined period of time. Furthermore, the deterioration diagnosis unit 773 determines that the instantaneous power is decreasing if the value obtained by dividing the instantaneous power by a reference value for instantaneous power falls below a predetermined value. The reference value for instantaneous power may be stored in the storage unit 75 at the time of manufacture or shipment of the power tool 7, or the instantaneous power calculated when the power tool 7 is first operated after purchase may be stored in the storage unit 75 as the reference value for instantaneous power.

[0055] Furthermore, the deterioration diagnosis unit 773 can calculate the amount of work by integrating the instantaneous power over time. Based on the amount of work obtained from the q-axis current measured by the current measurement unit 770, the deterioration diagnosis unit 773 diagnoses the progress of wear and deterioration of the impact mechanism 72. The deterioration diagnosis unit 773 determines that the q-axis current is decreasing when the amount of work is decreasing. The deterioration diagnosis unit 773 determines that the amount of work is decreasing when the decrease in the amount of work continues for a predetermined period of time. In addition, the deterioration diagnosis unit 773 determines that the amount of work is decreasing when the value obtained by dividing the amount of work by a reference value for the amount of work falls below a predetermined value. In this case, the reference value for the amount of work may be stored in the storage unit 75 at the time of manufacture or shipment of the power tool 7, or the amount of work calculated when the power tool 7 is first operated after purchase may be stored in the storage unit 75 as the reference value for the amount of work.

[0056] Furthermore, the deterioration diagnosis unit 773 determines that the q-axis current is decreasing if the average value of the q-axis current is decreasing. The deterioration diagnosis unit 773 determines that the average value of the q-axis current is decreasing if the decrease in the average value of the q-axis current continues for a predetermined period of time. Also, the deterioration diagnosis unit 773 determines that the average value of the q-axis current is decreasing if the value obtained by dividing the average value of the q-axis current by a reference value for the average value of the q-axis current is less than or equal to a predetermined value. In this case, the reference value for the average value of the q-axis current may be stored in the storage unit 75 at the time of manufacture or shipment of the power tool 7, or the average value of the q-axis current calculated when the power tool 7 is first operated after purchase may be stored in the storage unit 75 as the reference value for the average value of the q-axis current.

[0057] If the deterioration diagnosis unit 773 determines that wear deterioration of the impact mechanism 72 is progressing, the notification unit 774 notifies the outside that wear deterioration of the impact mechanism 72 is progressing.

[0058] If the deterioration diagnosis unit 773 determines that the impact mechanism 72 is not experiencing wear and deterioration, the notification unit 774 notifies an external party (for example, the operator of the power tool 7) by lighting up the LED on the display unit 76 in a display mode indicating that the impact mechanism 72 is not experiencing wear and deterioration. If the deterioration diagnosis unit 773 determines that the impact mechanism 72 is not experiencing wear and deterioration, the notification unit 774 notifies an external party that the impact mechanism 72 is not experiencing wear and deterioration by lighting up the LED on the display unit 76 in blue.

[0059] In other words, the notification unit 774 controls the display mode of the display unit 76 according to the judgment result of the deterioration diagnosis unit 773.

[0060] The prediction unit 775 predicts the occurrence of an abnormality due to the wear and deterioration of the impact mechanism 72, based on multiple measurement results of the q-axis current measured by the current measurement unit 770 in a time series. The prediction unit 775 uses a trained model that takes multiple measurement results of the q-axis current as input and outputs the timing of the abnormality to predict the occurrence of an abnormality due to the wear and deterioration of the impact mechanism 72.

[0061] As shown in Figure 2, the power tool 7 further comprises a tool housing 700. The tool housing 700 has a body portion 701, a grip portion 702, and a mounting portion 703.

[0062] The body portion 701 is formed in a cylindrical shape (here, cylindrical). The grip portion 702 protrudes from a part of the circumferential surface of the body portion 701 in one direction (downward in Figure 2). The mounting portion 703 is provided so that the power supply 710 can be detachably attached. In other words, the body portion 701 and the mounting portion 703 are connected by the grip portion 702.

[0063] The fuselage section 701 houses the motor 71, the impact mechanism 72, and a portion of the output shaft 73. The output shaft 73 protrudes from one end face of the fuselage section 701 in the axial direction along the axial direction D2.

[0064] The fuselage portion 701 of this embodiment has a rear fuselage portion 704 and a front fuselage portion 705. The rear fuselage portion 704 is the rear part of the fuselage portion 701 and is connected to the front fuselage portion 705 by a screw X1. The rear fuselage portion 704 is the part that is further from the output shaft 73 than the front fuselage portion 705. The front fuselage portion 705 is the front part of the fuselage portion 701 and is connected to the rear fuselage portion 704 by a screw X1. The output shaft 73 protrudes from one end face of the front fuselage portion 705 along the axial direction D2.

[0065] The front fuselage section 705 has a plurality of (three in the example in Figure 2) front connecting sections 707. In this embodiment, however, the front fuselage section 705 has four front connecting sections 707. The front connecting sections 707 protrude from the side surface of the front fuselage section 705 along the radial direction of the fuselage section 701. The four front connecting sections 707 are arranged along the circumferential direction of the fuselage section 701. Through holes are formed in the front connecting sections 707 for passing screws X1, and the screws X1 connect them to the rear connecting section 706, which will be described later.

[0066] The rear fuselage section 704 has a plurality of (three in the example in Figure 2) rear connecting sections 706. In this embodiment, however, the rear fuselage section 704 has four rear connecting sections 706. The rear connecting sections 706 protrude from the side surface of the rear fuselage section 704 along the radial direction of the fuselage section 701. The four rear connecting sections 706 are arranged along the circumferential direction of the fuselage section 701. The four rear connecting sections 706 correspond one-to-one with the four front connecting sections 707. The rear connecting sections 706 have screw holes corresponding to screws X1, and are connected to the corresponding front connecting sections 707 by screws X1.

[0067] In the following description, the front connecting portion 707 and the rear connecting portion 706, which are connected by a screw X1, may be referred to as the connecting portion 708. The connecting portion 708 is a protrusion provided on the tool housing 700. The shape of the connecting portion 708 is cylindrical, aligned with the axial direction D2 of the output shaft 73.

[0068] The grip portion 702 is the part that the operator holds when performing work. The grip portion 702 is equipped with a trigger 709. The trigger 709 is a switch for controlling the on / off operation of the motor 71. The trigger 709 has an initial position and an on position, and the motor 71 operates when the operator pushes or pulls the trigger 709 to the on position. In addition, the motor 71's rotation speed can be adjusted according to the amount of pull (operation) of the trigger 709.

[0069] The mounting portion 703 is formed in a flat rectangular parallelepiped shape. The power supply 710 is detachably mounted on one side of the mounting portion 703 opposite to the grip portion 702.

[0070] The power supply 710 is a battery pack. The power supply 710 is composed of, for example, a lithium-ion battery. The power supply 710 supplies power to the motor 71, memory unit 75, display unit 76, processing unit 77, and communication unit 79, etc. In other words, the power supply 710 is a power source that supplies power to the motor 71.

[0071] (2.3) Configuration of the Load Device Next, the configuration of the load device 1 of this embodiment will be described with reference to Figures 1 and 3 to 6. The load device 1 is a device that functions as a load for the tightening operation by the power tool 7. More specifically, the load device 1 functions as a load that simulates the object to be tightened, such as a screw, in the tightening operation by the power tool 7.

[0072] As shown in Figures 3 and 4, the load device 1 comprises a device housing 2, an installation section 3, an input section 4, a load section 5, and a base section 6.

[0073] In the following description, the direction D1 in which the installation section 3, input section 4, load section 5, and base section 6 are aligned is defined as the vertical direction. The direction from the installation section 3 towards the load section 5 is defined as downward, and the direction from the load section 5 towards the installation section 3 is defined as upward. Furthermore, the direction in which the front plate 21 and rear plate 23 of the device housing 2 are aligned is defined as the front-to-back direction. The direction from the front plate 21 towards the rear plate 23 is defined as rearward, and the direction from the rear plate 23 towards the front plate 21 is defined as forward. Furthermore, the direction in which the pair of side plates 22 of the device housing 2 are aligned is defined as the left-to-right direction. The vertical direction, the front-to-back direction, and the left-to-right direction are mutually orthogonal.

[0074] In this disclosure, "orthogonal (perpendicular)" means not only a state where the angle between two objects is exactly 90 degrees, but also a state where the two objects intersect within a certain range of difference. In other words, the angle between two orthogonal objects falls within a certain range of difference from 90 degrees (for example, 5 degrees or less). That is, "orthogonal" in this disclosure includes cases where the angle between two objects is between 85 degrees and 95 degrees.

[0075] The device housing 2 houses the input unit 4, the load unit 5, and the base unit 6. The device housing 2 is a rectangular box shape with an open bottom. The device housing 2 is made of synthetic resin. This makes it possible to reduce the weight of the load device 1.

[0076] As shown in Figure 4, the device housing 2 has a front plate 21, a pair of side plates 22, a rear plate 23, a top plate 24, and a flange portion 25. When the front plate 21, the pair of side plates 22, the rear plate 23, the top plate 24, and the flange portion 25 are combined, the device housing 2 is a rectangular box shape with an open bottom. In this embodiment, the device housing 2 is configured to be disassembled into the front plate 21, the pair of side plates 22, the rear plate 23, the top plate 24, and the flange portion 25.

[0077] The upper plate 24 has a plate-like shape with the normal of its main surface aligned in the vertical direction. An opening 241 is formed in the center of the upper plate 24, penetrating it in the vertical direction. When the power tool 7 is installed in the installation section 3, the output shaft 73 of the power tool 7 passes through the opening 241.

[0078] The front plate 21 is combined with the upper plate 24 so as to protrude downward from the front end of the upper plate 24. The shape of the front plate 21 is that of a plate with the normal of its main surface aligned in the front-to-back direction. An opening 211 is formed in the center of the front plate 21. The opening 211 is an opening that exposes at least a part of the load section 5 to the outside. The size of the opening 211 is large enough to allow the disc spring 52, which will be described later, to pass through. This allows, for example, an operator to adjust the number of disc springs 52 in the load section 5 without disassembling the device housing 2. In other words, an operator can adjust the amount of load during the tightening operation of the power tool 7 without disassembling the device housing 2.

[0079] The rear plate 23 is assembled with the upper plate 24 so as to protrude downward from the rear end of the upper plate 24. The shape of the rear plate 23 is that of a plate with the normal of its main surface aligned in the front-to-back direction.

[0080] One of the pair of side plates 22 is combined with the top plate 24 so as to protrude downward from the right end of the top plate 24, and the other of the pair of side plates 22 is combined with the top plate 24 so as to protrude downward from the left end of the top plate 24. The shape of the pair of side plates 22 is that of a plate with the normal of its main surface aligned in the front-to-back direction. An opening 221 is formed in the center of each of the pair of side plates 22. The opening 221 is an opening that exposes at least a part of the load section 5 to the outside. The size of the opening 221 is large enough to allow the disc spring 52 to pass through. This allows, for example, an operator to adjust the number of disc springs 52 in the load section 5 without disassembling the device housing 2. In other words, an operator can adjust the amount of load during the tightening operation of the power tool 7 without disassembling the device housing 2.

[0081] The shape of the flange portion 25 is rectangular. The normal to the main surface of the flange portion 25 is aligned in the vertical direction. The flange portion 25 is combined with the front plate 21, the pair of side plates 22, and the rear plate 23 so as to protrude outward from the lower ends of the front plate 21, the pair of side plates 22, and the rear plate 23.

[0082] The mounting portion 3 is positioned so as to rest on the upper plate 24 of the device housing 2. The mounting portion 3 is made of, for example, synthetic resin. However, the mounting portion 3 may be made of metal. The mounting portion 3 has a base portion 30, a first recess 32 (recess), a through hole 321, a plurality (four in the example of Figure 3) second recesses 322, and a plurality (four in the example of Figure 3) claw portions 33.

[0083] The base portion 30 is shaped like a rectangular parallelepiped. A first recess 32 is formed in the center of the upper surface 31 of the base portion 30, which is indented downwards. The shape of the first recess 32 follows the shape of the front body portion 705 of the tool housing 700 of the power tool 7. As shown in Figure 5, the shape of the first recess 32 is circular when viewed from above. The power tool 7 is installed in the first recess 32 such that the output shaft 73 protrudes downward from the front body portion 705.

[0084] Furthermore, when the power tool 7 is installed in the installation section 3, the axial direction D2 of the output shaft 73 is parallel to the alignment direction D1 of the installation section 3, the input section 4, and the load section 5. In this disclosure, "parallel" means not only a state in which the two do not strictly intersect, but also a state in which the two are aligned within a certain range of difference. For example, in this disclosure, "parallel" includes a state in which the inclination of one with respect to the other is 5 degrees or less. That is, in this disclosure, "parallel" includes a state in which the angle between one and the other is between -5 degrees and 5 degrees.

[0085] A through hole 321 is formed in the bottom surface of the first recess 32, which penetrates the base 30 in the vertical direction. The through hole 321 is a hole through which the output shaft 73 of the power tool 7 passes.

[0086] Multiple second recesses 322 are formed on the edge of the first recess 32. As shown in Figure 5, the second recesses 322 are recesses that are recessed radially outward from the first recess 32. The four second recesses 322 are arranged along the edge of the first recess 32, along the circumferential direction of the edge. The four second recesses 322 are provided at positions corresponding to the four connecting portions 708 (protrusions) of the tool housing 700 of the power tool 7. When the power tool 7 is installed on the installation portion 3, the connecting portions 708 of the tool housing 700 fit into the second recesses 322. As a result, the second recesses 322 restrict the rotation of the tool housing 700 along the rotation direction D3. According to the load device 1 of this embodiment, since the rotation of the tool housing 700 is restricted during the tightening operation of the power tool 7, the tightening operation of the power tool 7 can be stabilized and the accuracy of deterioration diagnosis can be improved.

[0087] Multiple claw portions 33 are provided on the upper surface 31 of the base portion 30. Four claw portions 33 are arranged around the first recess 32 and are aligned along the circumferential direction of the edge. The four claw portions 33 are provided at positions corresponding to the four connecting portions 708 (protrusions) of the tool housing 700 of the power tool 7. The four claw portions 33 include two pairs of claw portions 33, and when viewed from above, the pairs of claw portions 33 face each other with the first recess 32 in between. The shape of the claw portions 33 is L-shaped, protruding upward from the upper surface 31 of the base portion 30 and projecting toward the opposing claw portion 33.

[0088] When the power tool 7 is installed in the mounting section 3, the four claws 33 hook onto the upper ends of the four connecting sections 708 (protrusions) provided on the tool housing 700 of the power tool 7. As a result, in this embodiment, the mounting section 3 restricts the movement of the power tool 7 in the axial direction D2 of the output shaft 73 when the power tool 7 is installed in the first recess 32 of the mounting section 3. With the load device 1 of this embodiment, the movement of the power tool 7 in the axial direction D2 is restricted during the tightening operation of the power tool 7, thereby stabilizing the tightening operation of the power tool 7 and improving the accuracy of deterioration diagnosis.

[0089] Furthermore, the multiple claw portions 33 in this embodiment are configured to be elastically deformable. Therefore, the mounting portion 3 restricts the movement of the power tool 7 in the axial direction D2 by the elastic force with which the multiple claw portions 33 catch on the multiple connecting portions 708 (protrusions) provided on the tool housing 700 of the power tool 7. As a result, the movement of the power tool 7 in the axial direction D2 during the tightening operation of the power tool 7 can be further restricted, the tightening operation of the power tool 7 can be made more stable, and the accuracy of deterioration diagnosis can be further improved.

[0090] Furthermore, the multiple claw portions 33 hook onto the multiple connecting portions 708 (protrusions) of the tool housing 700 due to elastic force, generating sound and vibration when they hook. This allows the operator to be notified that the power tool 7 has been secured by the claw portions 33.

[0091] The input unit 4 is located between the installation unit 3 and the load unit 5 in the alignment direction D1. In other words, the input unit 4 is located below the installation unit 3 and above the load unit 5. As shown in Figure 6, the input unit 4 of this embodiment has a cylindrical body 41 and a cylindrical shaft 54. The body 41 and the shaft 54 ​​are concentric cylinders, and the diameter of the body 41 is larger than the diameter of the shaft 54.

[0092] A downwardly recessed connecting hole 411 is formed on the upper surface of the main body 41. The shape of the connecting hole 411 corresponds to the shape of the output shaft 73 of the power tool 7. The output shaft 73 of the power tool 7 is connected to the connecting hole 411. As shown in Figure 4, the lower surface of the main body 41 is the opposing surface 412. The opposing surface 412 faces the load section 5 in the alignment direction D1.

[0093] The shaft portion 54 protrudes downward from the lower surface of the main body portion 41. In other words, the shaft portion 54 protrudes in a direction toward the load portion 5 from the main body portion 41. A first threaded portion 541 is formed on at least the portion of the shaft portion 54 extending over a predetermined range from the tip (lower end). At least a portion of the tip side (lower end side) of the shaft portion 54 is inserted into the insertion hole 55 of the load portion 5. The first threaded portion 541 of the shaft portion 54 engages with a second threaded portion 551 formed in the insertion hole 55 of the load portion 5.

[0094] In this embodiment, the input unit 4 is supported by the load unit 5 so that it can rotate in the rotational direction D3 of the output shaft 73, by inserting the tip of the shaft 54 ​​into the insertion hole 55 of the load unit 5. The first threaded portion 541 and the second threaded portion 551 tighten (engage) as the input unit 4 rotates in the rotational direction D3.

[0095] The input unit 4 is rotated in the rotational direction D3 by the output shaft 73 of the power tool 7, causing it to be displaced from a first position to a second position in the direction D1 aligned with the load unit 5. The opposing surface 412 of the input unit 4 does not contact the load unit 5 when the input unit 4 is in the first position, and contacts the load unit 5 when the input unit 4 is in the second position. Here, the first position is, for example, the initial position of the input unit 4. The displacement of the input unit 4 from the first position to the second position due to the rotation of the output shaft 73 takes a predetermined amount of time or more, provided that the rotational speed of the output shaft 73 is within a predetermined range. The second position can be adjusted by the number of disc springs 52 of the load unit 5, which will be described later. The period of no load from when the output shaft 73 starts rotating until the input unit 4 is displaced to the second position is sometimes referred to as the "run-up period" in this disclosure.

[0096] Based on the q-axis current measured by the current measurement unit 770 during the warm-up period, for example, the hardness of the grease inside the power tool 7 or the load device 1 can be estimated, and by performing a deterioration diagnosis while taking the hardness of the grease into consideration, the accuracy of the deterioration diagnosis can be further improved. In other words, with the load device 1 of this embodiment, by providing a period of no load during the tightening operation by the power tool 7, the accuracy of the deterioration diagnosis can be further improved.

[0097] Figure 4 shows the case where the input unit 4 is in the second position. In the example in Figure 4, the opposing surface 412 of the input unit 4 is in contact with the bearing mechanism 56 of the load unit 5, which will be described later. The timing at which the input unit 4 comes into contact with the load unit 5 is, in other words, the timing at which the input unit 4 is seated on the load unit 5. In the tightening operation of the power tool 7, which is performed after the input unit 4 is seated on the load unit 5, the tightening torque increases rapidly.

[0098] After the input unit 4 is seated on the load unit 5, the input unit 4 is rotated in the rotational direction D3 by the output shaft 73 of the power tool 7, causing it to be displaced from the second position to the third position in the alignment direction D1. The third position is lower than the second position. In this embodiment, when the input unit 4 is displaced from the second position to the third position, the disc spring 52, which will be described later, is deformed.

[0099] Furthermore, the input unit 4 of this embodiment has a torque diode that restricts rotation in the reverse rotation direction D4 (see Figure 5), which is opposite to the rotation direction D3. The torque diode is, for example, a ratchet mechanism. This prevents the input unit 4 from rotating in the reverse rotation direction D4 if the output shaft 73 of the power tool 7 rotates in the reverse rotation direction D4 due to a setting error by the operator or the like. By preventing the input unit 4 from rotating in the reverse rotation direction D4, it is possible to prevent, for example, the input unit 4 from separating from the load unit 5.

[0100] Furthermore, the input unit 4 in this embodiment is configured to be detachable from the load device 1. This allows the input unit 4 to be replaced if, for example, the input unit 4 becomes deformed due to the tightening action of the power tool 7.

[0101] The load unit 5 is located between the input unit 4 and the base unit 6 in the alignment direction D1. In other words, the load unit 5 is located below the input unit 4 and above the base unit 6. As shown in Figure 6, the load unit 5 of this embodiment has a bearing mechanism 56, a support member 51, a plurality of disc springs 52, and a main body 53. The bearing mechanism 56, the support member 51, the plurality of disc springs 52, and the main body 53 are arranged from top to bottom in the alignment direction D1 in the order of bearing mechanism 56, support member 51, plurality of disc springs 52, and main body 53.

[0102] The support member 51 is formed in a cylindrical shape with a bottom. A through hole is formed in the bottom of the support member 51 through which the shaft portion 54 passes. A bearing mechanism 56 is placed on the upper surface of the bottom of the support member 51.

[0103] The bearing mechanism 56 is positioned between the upper surface of the bottom of the support member 51 and the opposing surface 412 of the main body 41 of the input unit 4. The bearing mechanism 56 reduces the frictional resistance of the main body 41 against the opposing surface 412 when the input unit 4 rotates. The bearing mechanism 56 includes a first washer, a thrust bearing, and a second washer. The thrust bearing is, for example, a thrust needle roller bearing. The thrust bearing is sandwiched between the first washer and the second washer in the vertical direction.

[0104] The multiple (eight in the example of Figure 4) disc springs 52 are annular disc springs. That is, when viewed from a direction perpendicular to the arrangement direction D1 (for example, the front-to-back direction), one of the disc springs 52 is convex on either its top or bottom side. In the example of Figure 4, the eight disc springs 52 are arranged such that the convex directions of two adjacent disc springs 52 in the vertical direction are opposite to each other. In this disclosure, an arrangement in which the convex directions of two adjacent disc springs 52 in the vertical direction are opposite to each other is called a "series arrangement". An arrangement in which the convex directions of two adjacent disc springs 52 in the vertical direction are the same is called a "parallel arrangement".

[0105] Furthermore, the uppermost disc spring 52 is positioned so as to be convex downwards, and the lowermost disc spring 52 is positioned so as to be convex upwards. The number of disc springs 52 and the direction of their convexity can be adjusted (set) as appropriate by, for example, the operator. By setting the number of disc springs 52 and the direction of their convexity, the load amount during the tightening operation of the power tool 7 can be adjusted. The load section 5 has disc springs 52 that are passed through the shaft section 54, thereby increasing the load when the input section 4 rotates as it rotates in the rotational direction D3.

[0106] The main body 53 has a base 531 and a connecting portion 532. The shape of the base 531 is cylindrical along the alignment direction D1. The base 531 has an annular upper surface 534. The upper surface 534 is the upper end of the base 531. The base 531 faces the disc spring 52 in the axial direction (up and down in this embodiment) of the shaft 54. More specifically, the upper surface 534 of the base 531 faces the lowest disc spring 52 among the multiple disc springs 52 in the up and down direction. An insertion hole 55 recessed downwards is formed in the upper surface 534 of the base 531. The shape of the insertion hole 55 is circular. The first threaded portion 541 of the shaft 54 ​​is inserted into the insertion hole 55. A second threaded portion 551 is formed in the insertion hole 55. The second threaded portion 551 corresponds to the first threaded portion 541. The first threaded portion 541 and the second threaded portion 551 tighten (engage) as the input portion 4 rotates in the rotational direction D3.

[0107] The connecting portion 532 protrudes downward from the lower surface of the base portion 531. The shape of the connecting portion 532 is that of a rectangular parallelepiped. The connecting portion 532 is inserted into a connecting hole 62 of the base portion 6, which will be described later. When the connecting portion 532 is inserted into the connecting hole 62 of the base portion 6, the load portion 5 is supported by the base portion 6 with its rotation restricted in the rotation direction D3 and the counter-rotation direction D4.

[0108] Furthermore, the load unit 5 in this embodiment is configured to be detachable from the load device 1. This allows the load unit 5 to be replaced if, for example, the load unit 5 is deformed due to the tightening action of the power tool 7.

[0109] The base portion 6 is located below the load portion 5 in the alignment direction D1. The base portion 6 is fixed to the rear plate 23 of the device housing 2. A downwardly recessed connecting hole 62 is formed on the upper surface 61 of the base portion 6. The shape of the connecting hole 62 is rectangular and corresponds to the shape of the connecting portion 532 of the load portion 5. The connecting portion 532 of the load portion 5 is inserted into the connecting hole 62.

[0110] Furthermore, the base portion 6 of this embodiment is provided with a torque detection unit 15 (see Figure 1). In other words, the load device 1 of this embodiment further includes a torque detection unit 15. The torque detection unit 15 detects the tightening torque when the output shaft 73 of the power tool 7 is rotated while the output shaft 73 of the power tool 7 is connected to the input portion. In other words, the torque detection unit 15 detects the tightening torque of the connecting portion 532 of the load portion 5 inserted into the connecting hole 62 during the tightening operation of the power tool 7. This allows the load device 1 to detect the tightening torque during the tightening operation of the power tool 7.

[0111] Next, other components of the load device 1 will be described. As shown in Figure 1, the load device 1 of this embodiment further comprises a communication unit 11, a notification unit 12, a storage unit 13, a processing unit 14, and an output unit 16.

[0112] The communication unit 11 has an interface that enables communication with the power tool 7. In this embodiment, the communication unit 11 has an interface that enables wired communication with the power tool 7 installed in the installation unit 3. The communication unit 11 receives predetermined information from the power tool 7.

[0113] The processing unit 14 includes a computer system having one or more processors and memory. At least some of the functions of the processing unit 14 are realized when the processor of the computer system executes a program recorded in the memory of the computer system. The program may be recorded in memory, provided via a telecommunication line such as the Internet, or provided on a non-temporary recording medium such as a memory card.

[0114] The processing unit 14 in this embodiment has the same functions as the deterioration diagnosis unit 773 and prediction unit 775 of the power tool 7. In other words, the processing unit 14 uses the q-axis current measured by the current measurement unit 770 of the power tool 7 to diagnose the progress of wear deterioration of the impact mechanism 72.

[0115] More specifically, the processing unit 14 acquires predetermined information from the power tool 7 via the communication unit 11 and diagnoses the wear and deterioration status of the impact mechanism 72 of the power tool 7 based on the predetermined information. The predetermined information in this embodiment includes information on the q-axis current supplied to the motor 71 and information on the rotational speed when the power tool 7 rotates the output shaft 73 until the tightening torque reaches a specified torque, with the output shaft 73 of the power tool 7 connected to the input unit 4. This allows the load device 1 to diagnose the deterioration of the impact mechanism 72 of the power tool 7. However, the predetermined information only needs to include information on the q-axis current and does not need to include information on the rotational speed.

[0116] Furthermore, the processing unit 14 predicts the occurrence of an abnormality due to the wear and deterioration of the impact mechanism 72, based on multiple measurement results of the q-axis current measured by the current measurement unit 770 in a time-series manner. The processing unit 14 uses a trained model, which takes multiple measurement results of the q-axis current as input and outputs the timing of the abnormality, to predict the occurrence of an abnormality due to the wear and deterioration of the impact mechanism 72.

[0117] The notification unit 12 displays the diagnosis result of wear and deterioration of the impact mechanism 72. The notification unit 12 has, for example, an LED and displays the diagnosis result of the deterioration diagnosis performed by the processing unit 14. The notification unit 12 is provided, for example, on the base 6. For example, a through hole is formed in the front plate 21 of the device housing 2 so that the notification unit 12 provided on the base 6 is exposed to the outside of the load device 1. If, for example, the processing unit 14 determines that wear and deterioration of the impact mechanism 72 is not progressing, the notification unit 12 lights up the LED in a display mode indicating that wear and deterioration of the impact mechanism 72 is not progressing. In addition, if the processing unit 14 determines that wear and deterioration of the impact mechanism 72 is not progressing, the notification unit 12 lights up the LED in blue. This makes it possible to notify the operator of the diagnosis result of the deterioration diagnosis. The notification unit 12 may be provided on the device housing 2 or the installation unit 3.

[0118] Furthermore, the notification unit 12 uses an LED to notify the user of the predicted occurrence of an abnormality due to the wear and deterioration of the impact mechanism 72.

[0119] The notification unit 12 may include a display unit such as an LCD (Liquid Crystal Display) instead of or in addition to the LED, or it may have a speaker or the like. For example, the notification unit 12 may notify the results of the degradation diagnosis using a display unit such as an LCD, or it may notify them by sound.

[0120] The memory unit 13 is composed of a device selected from ROM, RAM, or EEPROM, etc. The memory unit 13 stores information used to diagnose wear and deterioration of the impact mechanism 72 (i.e., wear and deterioration of the hammer and anvil).

[0121] The memory unit 13 stores predetermined information acquired by the processing unit 14. The memory unit 13 also stores identification information of the power tool 7 targeted for diagnosis by the processing unit 14, the diagnosis results of the deterioration diagnosis performed by the processing unit 14, and the date and time the processing unit 14 performed the diagnosis. This allows the memory unit 13 to store information regarding measurement results and deterioration diagnosis related to the power tool 7.

[0122] The output unit 16 outputs predetermined information stored in the storage unit 13. For example, the output unit 16 has an interface for outputting predetermined information stored in the storage unit 13 to an external terminal. In this embodiment, the output unit 16 has a USB port to which a USB (Universal Serial Bus) connector is connected. This allows predetermined information stored in the storage unit 13 to be output to an external terminal such as a USB memory device.

[0123] (3) Operation of the load system Next, the operation of the load system 100 will be described with reference to Figure 7.

[0124] First, the operator places (sets) the power tool 7 onto the load device 1. Once the power tool 7 is placed on the load device 1, the load device 1 detects the power tool 7 (step S1). Next, the load device 1 determines the operating mode (step S2). The operating modes of the load device 1 include a diagnostic mode and a test mode. The diagnostic mode is used to diagnose the deterioration of the power tool 7. The test mode is used to accumulate predetermined information about the tightening operation performed by the power tool 7. This predetermined information may include the results of the deterioration diagnosis performed on the power tool 7. The load device 1 determines the operating mode based, for example, on the operator's operation of the load device 1.

[0125] Next, the power tool 7 is operated by the worker to perform a tightening operation and tighten the input section 4 of the load device 1 (step S3). Next, the power tool 7 and the load device 1 communicate via wire (step S4). The load device 1 receives predetermined information from the power tool 7.

[0126] Next, the load device 1 determines whether or not to perform a deterioration diagnosis of the power tool 7 on the load device 1 side (jig side), that is, whether or not the operating mode is the diagnosis mode (step S5). If the load device 1 determines that the operating mode is not the diagnosis mode, that is, the operating mode is the test mode (step S5: No), it stores predetermined information received from the power tool 7 in the storage unit 13 (step S6), and terminates the series of processes shown in Figure 7.

[0127] On the other hand, if the load device 1 determines that the operating mode is diagnostic mode (step S5: Yes), the load device 1 performs a deterioration diagnosis of the impact mechanism 72 based on the q-axis current information and rotational speed information included in the predetermined information (step S7). After performing the deterioration diagnosis, the load device 1 stores the diagnosis result of the deterioration diagnosis in the storage unit 13 (step S8).

[0128] Next, the load device 1 predicts the occurrence of an abnormality due to the progression of wear and deterioration of the impact mechanism 72, based on multiple diagnostic results of the accumulated deterioration diagnosis (step S9). In other words, the load device 1 predicts the occurrence of an abnormality due to the progression of wear and deterioration of the impact mechanism 72, based on multiple measurement results of the q-axis current in a time series. The multiple diagnostic results of the accumulated deterioration diagnosis are diagnostic results corresponding to the identification information of the power tool 7 installed in the installation section 3.

[0129] Next, the load device 1 notifies the notification unit 12 of at least one of the deterioration diagnosis results and the abnormality occurrence prediction results (step S10), and then terminates the series of processes shown in Figure 7.

[0130] Note that the flowchart shown in Figure 7 is merely an example, and the order of processing may be changed as appropriate, or processes may be added or deleted as appropriate.

[0131] (4) Modifications Below are some modifications of the above embodiment.

[0132] (4.1) Modification 1 As shown in Figure 8, the load system 100 of Modification 1 further comprises a server 8.

[0133] Server 8 manages multiple power tools 7. More specifically, in the modified example 1, Server 8 manages the wear and deterioration status of multiple power tools 7. Server 8 includes a communication unit 81, a control unit 83, and a storage unit 82.

[0134] The communication unit 81 has an interface that enables communication with the power tool 7 and the load device 1. More specifically, the communication unit 81 has an interface configured to enable wireless communication with the power tool 7 and the load device 1. The communication unit 81 receives predetermined information about the power tool 7, the results of deterioration diagnosis, and the prediction results of abnormal occurrences from the power tool 7 or the load device 1.

[0135] The storage unit 82 is composed of a device selected from ROM, RAM, or EEPROM, etc. The storage unit 82 stores predetermined information about the power tool 7, the results of the deterioration diagnosis, and the prediction results of the occurrence of abnormalities, etc., in association with the identification information of the power tool 7.

[0136] The control unit 83 includes a computer system having one or more processors and memory. At least some of the functions of the control unit 83 are realized when the processor of the computer system executes a program recorded in the memory of the computer system. The program may be recorded in memory, provided via a telecommunication line such as the Internet, or provided on a non-temporary recording medium such as a memory card.

[0137] The control unit 83 has a deterioration diagnosis unit 773. The function of the deterioration diagnosis unit 773 is the same as that of the deterioration diagnosis unit 773 of the power tool 7. The control unit 83 may also have the function of a prediction unit 775.

[0138] The communication unit 79 of the power tool 7 in Modification 1 has an interface configured to enable wireless communication with the server 8 and the load device 1. The communication unit 79 transmits predetermined information about the power tool 7, the results of the deterioration diagnosis, and the prediction results of the occurrence of abnormalities to the server 8.

[0139] The communication unit 11 of the load device 1 in Modification 1 has an interface configured to enable wireless communication with the power tool 7, the server 8, and other load devices 1. In other words, the load device 1 in Modification 1 includes a wireless communication unit configured to enable wireless communication with the server 8 that manages the power tool 7, or with other load devices 1.

[0140] For example, the communication unit 11 transmits the diagnostic results of a degradation diagnosis performed by the load device 1 or the prediction results of an abnormality occurrence to the server 8 or another load device 1. The communication unit 11 also transmits predetermined information about the power tools 7 stored in the storage unit 13 to the server 8 or another load device 1. This makes it easy for the server 8 to manage multiple power tools 7.

[0141] (4.2) Modification 2 In the above embodiment, an example was given in which the input unit 4 has a shaft portion 54 and the load unit 5 has an insertion hole 55. However, it is sufficient if one of the input unit 4 and the load unit 5 has a cylindrical shaft portion 54 and the other of the input unit 4 and the load unit 5 has an insertion hole 55.

[0142] As shown in Figure 9, in the modified example 2 of the load device 1, the load section 5 has a shaft section 54, and the input section 4 has an insertion hole 55. Similar to the above embodiment, a first threaded section 541 is formed on at least the portion of the shaft section 54 extending over a predetermined range from the tip. The first threaded section 541 of the shaft section 54 is inserted into the insertion hole 55, and a second threaded section 551 corresponding to the first threaded section 541 is formed.

[0143] The insertion hole 55 is formed on the lower surface of the main body 41. In the modified example 2, the insertion hole 55 is recessed upward. A second threaded portion 551 is formed in the insertion hole 55. The shaft portion 54 of the load portion 5 is inserted into the insertion hole 55. As a result, the input portion 4 is supported by the load portion 5 in a state where it can rotate in the rotational direction D3.

[0144] The shaft portion 54 protrudes upward from the upper surface 534 of the base portion 531. In other words, the shaft portion 54 protrudes from the base portion 531 of the load portion 5 toward the input portion 4. The shape of the shaft portion 54 is cylindrical along the alignment direction D1. A first threaded portion 541 is formed on at least the portion of the shaft portion 54 extending over a predetermined range from the tip (upper end). At least a portion of the tip side (upper end side) of the shaft portion 54 is inserted into the insertion hole 55 of the input portion 4. The first threaded portion 541 of the shaft portion 54 engages with the second threaded portion 551 formed in the insertion hole 55. The first threaded portion 541 and the second threaded portion 551 tighten (engage) as the input portion 4 rotates in the rotation direction D3.

[0145] Similar to the above embodiment, the load unit 5 has a disc spring 52 that passes through the shaft 54. As a result, the load unit 5 increases the load on the input unit 4 as it rotates in the rotational direction D3.

[0146] (4.3) Modification 3 As shown in Figure 10, the shaft portion 54 of Modification 3 is magnetized such that the magnetization direction is along the radial direction of the shaft portion 54. In addition, each of the multiple (only one is shown in Figure 10) disc springs 52 is magnetized such that the magnetization direction is along the radial direction of the disc spring 52. The radial direction of the shaft portion 54 and the radial direction of the disc springs 52 are perpendicular to the vertical direction and are radial directions centered on the center 542 of the shaft portion 54.

[0147] In the modified example 3, the shaft portion 54 is a radially magnetized magnet. However, it is not necessary for the entire shaft portion 54 to be a radially magnetized magnet; the shaft portion 54 may have a radially magnetized magnet.

[0148] Furthermore, the disc spring 52 in the modified example 3 is a radially magnetized magnet. However, it is not necessary for the entire disc spring 52 to be a radially magnetized magnet; the disc spring 52 may have a radially magnetized magnet.

[0149] In the third modified example, the radially outer magnetic pole of the shaft portion 54 and the radially inner magnetic pole of the disc spring 52 are the same pole (N pole in the example of Figure 10). As a result, the shaft portion 54 and the disc spring 52 repel each other in the radial direction, and the displacement of the disc spring 52 relative to the shaft portion 54 in the radial direction can be suppressed.

[0150] Furthermore, because adjacent disc springs 52 repel each other in the vertical direction, the load on the power tool 7 during the tightening operation can be increased.

[0151] Furthermore, the radially outer magnetic pole of the shaft portion 54 and the radially inner magnetic pole of the disc spring 52 may be opposite poles. When the radially outer magnetic pole of the shaft portion 54 and the radially inner magnetic pole of the disc spring 52 are opposite poles, the shaft portion 54 and the disc spring 52 attract each other, which can suppress the displacement of the disc spring 52 relative to the shaft portion 54 in the radial direction.

[0152] (4.4) Modified Example 4 As shown in Figure 11, the main body 53 of the load unit 5 in Modified Example 4 has a plurality of (four in the example of Figure 11) first fitting portions 533. More specifically, the plurality of first fitting portions 533 are formed on the upper surface 534 of the base portion 531 of the main body 53.

[0153] The multiple first fitting portions 533 are protrusions that project upward from the upper surface 534. Each of the multiple first fitting portions 533 is formed along the radial direction of the upper surface 534 (i.e., the radial direction of the main body portion 53). The multiple first fitting portions 533 are arranged at equal intervals (i.e., equal angular intervals) in the circumferential direction of the upper surface 534 (i.e., the circumferential direction of the main body portion 53).

[0154] In the example shown in Figure 11, four disc springs 52 are positioned above the main body 53. The four disc springs 52 are arranged in parallel in an upward-convex direction. However, the number and arrangement of the disc springs 52 can be adjusted (set) as appropriate.

[0155] Each of the multiple disc springs 52 in Modification 4 has a main body portion 521, a plurality of (four in the example of Figure 11) second fitting portions 522, and a plurality of (four in the example of Figure 11) third fitting portions 523.

[0156] The main body portion 521 has an annular plate shape. When viewed from a direction perpendicular to the alignment direction D1 (for example, the front-to-back direction), the main body portion 521 has a mountain-like shape with one side convex in either the up or down direction. In the example in Figure 11, the disc spring 52 is arranged such that the main body portion 521 is convex in the upward direction.

[0157] The main body 521 has a first surface 524 and a second surface 525. The first surface 524 is the outer surface. The second surface 525 is the surface opposite the first surface 524 and is the inner surface. In the example in Figure 11, the first surface 524 is the top surface and the second surface 525 is the bottom surface.

[0158] The multiple second fitting portions 522 are recesses formed on the second surface 525 of the main body portion 521. Each of the multiple second fitting portions 522 is formed along the radial direction of the second surface 525 (i.e., the radial direction of the disc spring 52). The multiple second fitting portions 522 are arranged at equal intervals (i.e., equal angular intervals) in the circumferential direction of the second surface 525 (i.e., the circumferential direction of the disc spring 52).

[0159] The multiple first fitting portions 533 of the main body 53 correspond one-to-one with the multiple second fitting portions 522 of the lowest-positioned disc spring 52 among the multiple disc springs 52. The multiple first fitting portions 533 and the multiple second fitting portions 522 of the lowest-positioned disc spring 52 among the multiple disc springs 52 engage with each other. The engagement of the multiple first fitting portions 533 of the main body 53 with the multiple second fitting portions 522 of the highest-positioned disc spring 52 among the multiple disc springs 52 positions the lowest-positioned disc spring 52 relative to the main body 53. This suppresses misalignment of the disc spring 52 relative to the shaft 54 ​​in the radial direction.

[0160] The multiple third fitting portions 523 are protrusions that project from the first surface 524 of the main body portion 521. Each of the multiple third fitting portions 523 is formed along the radial direction of the first surface 524 (i.e., the radial direction of the disc spring 52). The multiple third fitting portions 523 are arranged at equal intervals (i.e., equal angular intervals) in the circumferential direction of the first surface 524 (i.e., the circumferential direction of the disc spring 52).

[0161] Multiple third fitting portions 523 and multiple second fitting portions 522 correspond one-to-one. Multiple third fitting portions 523 engage with multiple second fitting portions 522 of other disc springs 52 adjacent to each other in the vertical direction (the upper disc spring 52 in the example of Figure 11). The engagement of the multiple third fitting portions 523 and the multiple second fitting portions 522 positions two disc springs 52 adjacent to each other in the vertical direction. This suppresses misalignment of the disc springs 52 relative to the shaft portion 54 in the radial direction.

[0162] Modification 4 illustrates a case where the first fitting portion 533 is a convex portion, the second fitting portion 522 is a concave portion, and the third fitting portion 523 is a convex portion. However, the first fitting portion 533 may be a concave portion, the second fitting portion 422 may be a convex portion, and the third fitting portion 523 may be a concave portion.

[0163] The support member 51 positioned above the multiple disc springs 52 may have multiple first fitting portions 533. More specifically, multiple first fitting portions 533 may be formed on the lower surface of the support member 51. The multiple first fitting portions 533 of the support member 51 and the multiple second fitting portions 522 of the uppermost disc spring 52 among the multiple disc springs 52 are fitted together, thereby positioning the uppermost disc spring 52 among the multiple disc springs 52 with respect to the support member 51. This makes it possible to suppress misalignment of the disc springs 52 with respect to the shaft portion 54 in the radial direction.

[0164] Modification 4 illustrates a case where there are multiple first fitting portions 533, second fitting portions 522, and third fitting portions 523. However, each of the first fitting portion 533, second fitting portion 522, and third fitting portion 523 may be a single fitting portion.

[0165] Modification 4 illustrates a case where the first fitting portion 533, the second fitting portion 522, and the third fitting portion 523 are formed along the radial direction. However, the first fitting portion 533, the second fitting portion 522, and the third fitting portion 523 may also be formed along the circumferential direction.

[0166] (4.5) Other Modifications The fact that multiple functions of the load system 100 are integrated into a single housing is not an essential configuration for the load system 100, and the components of the load system 100 may be distributed across multiple housings. Furthermore, at least some of the functions of the load system 100, for example, some of the functions of the load device 1, may be realized by the cloud (cloud computing), etc.

[0167] In the above embodiment, at least some of the functions of the load system 100, which are distributed across multiple devices, may be consolidated into a single housing. For example, some of the functions of the load system 100, which are distributed across the load device 1 and the power tool 7, may be consolidated into a single housing.

[0168] In the above embodiment, a case is illustrated in which multiple (eight in the example of Figure 4) disc springs 52 are arranged in series. However, as mentioned above, the number of disc springs 52 and the direction of the convex direction of the disc springs 52 can be adjusted (set) as appropriate by, for example, an operator. For example, multiple disc springs 52 may be arranged in parallel. Also, as shown in Figure 12, a group of disc springs 52A including multiple (five in the example of Figure 12) disc springs 52 arranged in parallel may be arranged in series with the group of disc springs 52A.

[0169] (Modes) As is clear from the embodiments and modifications described above, the load device (1) according to the first mode comprises an installation part (3), an input part (4), and a load part (5). The installation part (3) has a recess (first recess 32) and a through hole (321). An electric power tool (7) is installed in the recess. The electric power tool (7) has a tool housing (700) that houses a motor (71), and an output shaft (73) that protrudes from the tool housing (700). The output shaft (73) passes through the through hole (321). The installation part (3) restricts the rotation of the tool housing (700) when the electric power tool (7) is installed in the recess. The input part (4) is connected to the output shaft (73) that passes through the through hole (321) and is supported so as to be rotatable in the rotational direction (D3) of the output shaft (73). The load unit (5) is connected to the input unit (4), and the load on the input unit (4) increases as it rotates in the rotational direction (D3).

[0170] According to this embodiment, a tightening operation can be performed by the power tool (7) using the load device (1). This makes it easier to perform diagnostics to understand the condition of the power tool (7), for example.

[0171] In the load device (1) according to the second embodiment, the mounting portion (3) further has a second recess (322) as in the first embodiment. The second recess (322) is a different recess from the first recess (32) and is formed in the first recess (32). The mounting portion (3) restricts the rotation of the tool housing (700) by fitting the second recess (322) with a protrusion (connecting portion 708) provided on the tool housing (700) of the power tool (7).

[0172] According to this embodiment, the tightening operation of the power tool (7) can be stabilized, and for example, the accuracy of deterioration diagnosis can be improved.

[0173] In the third embodiment of the load device (1), in the first or second embodiment, the installation part (3) restricts the movement of the power tool (7) in the axial direction (D2) of the output shaft (73) when the power tool (7) is installed in the recess (first recess 32).

[0174] According to this embodiment, the tightening operation of the power tool (7) can be stabilized, and for example, the accuracy of deterioration diagnosis can be improved.

[0175] In the load device (1) according to the fourth embodiment, the mounting part (3) further has a plurality of claw parts (33). The mounting part (3) restricts the movement of the power tool (7) in the axial direction (D2) of the output shaft (73) by having the plurality of claw parts (33) catch on a plurality of protrusions (connecting parts 708) provided on the tool housing (700) of the power tool (7).

[0176] In the fifth embodiment of the load device (1), the plurality of claw portions (33) are configured to be elastically deformable, as in the fourth embodiment. The mounting portion (3) restricts the movement of the power tool (7) in the axial direction (D2) of the output shaft (73) by the plurality of claw portions (33) elastically catching on a plurality of protrusions (connecting portions 708) provided on the tool housing (700) of the power tool (7).

[0177] According to this embodiment, the tightening operation of the power tool (7) can be made more stable, and for example, the accuracy of deterioration diagnosis can be further improved.

[0178] In the sixth embodiment of the load device (1), in any of the first to fifth embodiments, the input section (4) has a cylindrical shaft section (54) into which a first threaded section (541) is formed over a predetermined range from at least the tip. The load section (5) has an insertion hole (55) into which the first threaded section (541) of the shaft section (54) is inserted, and into which a second threaded section (551) corresponding to the first threaded section (541) is formed. The first threaded section (541) and the second threaded section (551) tighten as the input section (4) rotates in the rotational direction (D3). The load section (5) has a disc spring (52) that passes through the shaft section (54), thereby increasing the load on the input section (4) as it rotates in the rotational direction (D3).

[0179] In the seventh embodiment of the load device (1), in any of the first to fifth embodiments, the load portion (5) has a cylindrical shaft portion (54) into which a first threaded portion (541) is formed over a predetermined range from at least the tip. The input portion (4) has an insertion hole (55) into which the first threaded portion (541) of the shaft portion (54) is inserted, and into which a second threaded portion (551) corresponding to the first threaded portion (541) is formed. The first threaded portion (541) and the second threaded portion (551) tighten as the input portion (4) rotates in the rotational direction (D3). The load portion (5) has a disc spring (52) that passes through the shaft portion (54), thereby increasing the load when the input portion (4) rotates as it rotates in the rotational direction (D3).

[0180] The load device (1) according to the eighth embodiment further comprises a device housing (2) that houses an input unit (4) and a load unit (5) according to the sixth or seventh embodiment. The device housing (2) has openings (211; 221) that expose at least a portion of the load unit (5) to the outside. The size of the openings (211; 221) is such that a disc spring (52) can pass through.

[0181] According to this embodiment, for example, an operator can adjust the number of disc springs (52) in the load section (5) without disassembling the device housing (2).

[0182] In the ninth embodiment of the load device (1), in any of the sixth to eighth embodiments, the input unit (4) is rotated in the rotational direction (D3) by the output shaft (73), thereby displacing it from a first position to a second position in the direction of alignment (D1) with the load unit (5). The input unit (4) further has a facing surface (412) that faces the load unit (5) in the direction of alignment (D1). The facing surface (412) does not contact the load unit (5) when the input unit (4) is in the first position, but contacts the load unit (5) when the input unit (4) is in the second position.

[0183] According to this embodiment, by providing a period of no load during the tightening operation by the power tool (7), the accuracy of deterioration diagnosis can be further improved, for example.

[0184] In the load device (1) according to the tenth embodiment, in any of the sixth to ninth embodiments, the shaft portion (54) is magnetized such that the magnetization direction is along the radial direction of the shaft portion (54). The shape of the disc spring (52) is annular. The disc spring (52) is magnetized such that the magnetization direction is along the radial direction of the disc spring (52).

[0185] According to this embodiment, misalignment of the disc spring (52) with respect to the shaft portion (54) can be suppressed.

[0186] In the load device (1) according to the 11th embodiment, in any of the 6th to 10th embodiments, the load portion (5) has a main body portion (53) facing the disc spring (52) in the axial direction of the shaft portion (54), and the main body portion (53) has a first fitting portion (533). The disc spring (52) has a second fitting portion (522) that fits with the first fitting portion (533).

[0187] According to this embodiment, misalignment of the disc spring (52) with respect to the shaft portion (54) can be suppressed.

[0188] The load device (1) according to the twelfth embodiment comprises a device housing (2) that houses an input unit (4) and a load unit (5) in any of the first to eleventh embodiments. The device housing (2) is made of a resin material.

[0189] According to this embodiment, the load device (1) can be made lighter.

[0190] In the load device (1) according to the 13th embodiment, in any of the first to 12 embodiments, the input unit (4) has a torque diode that restricts rotation in the reverse rotation direction (D4) which is opposite to the rotation direction (D3).

[0191] According to this embodiment, it is possible to suppress the input unit (4) from rotating in the reverse direction (D4).

[0192] The load device (1) according to the 14th embodiment further comprises a torque detection unit (15) in any of the first to 13th embodiments. The torque detection unit (15) detects the tightening torque when the power tool (7) rotates the output shaft (73) while the output shaft (73) of the power tool (7) is connected to the input unit (4).

[0193] According to this embodiment, the tightening torque during the tightening operation of the power tool (7) can be detected by the load device (1).

[0194] In the load device (1) according to the 15th embodiment, the load section (5) is configured to be detachable in any of the first to 14th embodiments.

[0195] According to this embodiment, the load part (5) can be replaced if it becomes deformed or for other reasons.

[0196] The load device (1) according to the 16th embodiment further comprises a communication unit (11), a deterioration diagnosis unit (processing unit 14), and a notification unit (12) in any of the first to 15 embodiments. The communication unit (11) is configured to communicate with an electric tool (7), which is an impact power tool equipped with an impact mechanism (72). The deterioration diagnosis unit obtains predetermined information from the electric tool (7) via the communication unit (11). Based on the predetermined information, the deterioration diagnosis unit diagnoses the progress of wear deterioration of the impact mechanism (72) of the electric tool (7). The notification unit (12) notifies the diagnosis result from the deterioration diagnosis unit. The predetermined information is information on the q-axis current supplied to the motor (71) when the output shaft (73) of the electric tool (7) is connected to the input unit (4) and the electric tool (7) rotates the output shaft (73) until the tightening torque reaches a specified torque.

[0197] According to this embodiment, the load device (1) can perform a deterioration diagnosis of the impact mechanism (72) of the power tool (7). Furthermore, the results of the deterioration diagnosis can be notified to the operator.

[0198] The load device (1) according to the 17th embodiment further comprises a storage unit (13) and an output unit (16) according to the 16th embodiment. The storage unit (13) stores predetermined information acquired by the deterioration diagnosis unit (processing unit 14). The output unit (16) outputs the predetermined information stored in the storage unit (13).

[0199] According to this embodiment, predetermined information can be output to an external terminal such as a USB memory stick.

[0200] The load device (1) according to the 18th embodiment includes a storage unit (13) according to the 16th or 17th embodiment. The storage unit (13) stores identification information of the power tool (7) that the deterioration diagnosis unit (processing unit 14) has diagnosed, the diagnosis results by the deterioration diagnosis unit, and information on the date and time the deterioration diagnosis unit performed the diagnosis.

[0201] According to this embodiment, information regarding deterioration diagnosis can be stored.

[0202] The load device (1) according to the 19th embodiment further comprises a wireless communication unit (communication unit 11) in any of the first to 18th embodiments. The wireless communication unit is configured to communicate wirelessly with a server (8) that manages the power tools (7) or with other load devices (1).

[0203] According to this embodiment, it becomes easy to manage, for example, multiple power tools (7) on the server (8).

[0204] Configurations other than those in the first embodiment are not essential to the load device (1) and can be omitted as appropriate.

[0205] 1 Load device 11 Communication unit (wireless communication unit) 12 Notification unit 13 Memory unit 14 Processing unit (deterioration diagnosis unit) 15 Torque detection unit 16 Output unit 2 Device housing 211 Opening 221 Opening 3 Installation unit 32 First recess (recess) 321 Through hole 322 Second recess 33 Claw unit 4 Input unit 412 Opposing surface 5 Load unit 52 Disc spring 522 Second fitting unit 53 Main body unit 533 First fitting unit 54 Shaft unit 541 First screw unit 55 Insertion hole 551 Second screw unit 7 Power tool 700 Tool housing 708 Connecting unit (protrusion) 71 Motor 72 Impact mechanism 73 Output shaft 773 Deterioration diagnosis unit 8 Server D1 Alignment direction D2 Axial direction D3 Rotation direction D4 Reverse rotation direction

Claims

1. A load device comprising: an installation part having a tool housing for a motor and a recess in which an electric power tool having an output shaft protruding from the tool housing is installed, and a through hole through which the output shaft passes, the installation part restricting the rotation of the tool housing when the electric power tool is installed in the recess; an input part connected to the output shaft passing through the through hole and supported so as to be rotatable in the rotational direction of the output shaft; and a load part connected to the input part, which increases the load on the input part as it rotates in the rotational direction.

2. The loading device according to claim 1, wherein the mounting portion is a recess separate from the first recess which is the recess, and further has a second recess formed in the first recess, and the rotation of the tool housing is restricted when the second recess and a protrusion provided on the tool housing of the power tool are fitted together.

3. The loading device according to claim 1 or 2, wherein the mounting portion restricts the movement of the power tool in the axial direction of the output shaft when the power tool is installed in the recess.

4. The load device according to claim 3, wherein the mounting portion further has a plurality of claw portions, and the plurality of claw portions catch on a plurality of protrusions provided on the tool housing of the power tool, thereby restricting the movement of the power tool in the axial direction of the output shaft.

5. The load device according to claim 4, wherein the plurality of claws are configured to be elastically deformable, and the mounting portion restricts the movement of the power tool in the axial direction of the output shaft by the plurality of claws elastically catching on a plurality of protrusions provided on the tool housing of the power tool.

6. The input portion has a cylindrical shaft portion in which a first threaded portion is formed over a predetermined range from at least the tip; the load portion has an insertion hole into which the first threaded portion of the shaft portion is inserted and into which a second threaded portion corresponding to the first threaded portion is formed; the first threaded portion and the second threaded portion tighten as the input portion rotates in the rotational direction; and the load portion has a disc spring passed through the shaft portion, thereby increasing the load on the input portion as it rotates in the rotational direction, according to any one of claims 1 to 5.

7. The load device according to any one of claims 1 to 5, wherein the load portion has a cylindrical shaft portion into which a first threaded portion is formed over a predetermined range from at least the tip, the input portion has an insertion hole into which the first threaded portion of the shaft portion is inserted and into which a second threaded portion corresponding to the first threaded portion is formed, the first threaded portion and the second threaded portion tighten as the input portion rotates in the rotational direction, and the load portion has a disc spring passed through the shaft portion, thereby increasing the load when the input portion rotates as it rotates in the rotational direction.

8. The load device according to claim 6 or 7, further comprising a device housing for housing the input unit and the load unit, wherein the device housing has an opening formed therein that exposes at least a part of the load unit to the outside, and the size of the opening is such that the disc spring can pass through.

9. The load device according to any one of claims 6 to 8, wherein the input unit is rotated in the rotational direction by the output shaft, thereby displacing it from a first position to a second position in the direction of alignment with the load unit, and further having a facing surface that faces the load unit in the direction of alignment, the facing surface not in contact with the load unit when the input unit is in the first position, and in contact with the load unit when the input unit is in the second position.

10. The load device according to any one of claims 6 to 9, wherein the shaft portion is magnetized such that the magnetization direction is along the radial direction of the shaft portion, the shape of the disc spring is annular, and the disc spring is magnetized such that the magnetization direction is along the radial direction of the disc spring.

11. The load device according to any one of claims 6 to 10, wherein the load portion has a main body portion facing the disc spring in the axial direction of the shaft portion, the main body portion has a first fitting portion, and the disc spring has a second fitting portion that fits with the first fitting portion.

12. The load device according to any one of claims 1 to 11, further comprising a device housing for housing the input unit and the load unit, wherein the device housing is made of a resin material.

13. The load device according to any one of claims 1 to 12, wherein the input section has a torque diode that restricts rotation in the opposite direction to the rotation direction.

14. The load device according to any one of claims 1 to 13, further comprising a torque detection unit for detecting the tightening torque when the power tool rotates the output shaft while the output shaft of the power tool is connected to the input unit.

15. The load device according to any one of claims 1 to 14, wherein the load portion is configured to be detachable.

16. A load device according to any one of claims 1 to 15, further comprising: an impact power tool equipped with an impact mechanism; a communication unit configured to communicate; a deterioration diagnosis unit that acquires predetermined information from the power tool via the communication unit and diagnoses the progress of wear deterioration of the impact mechanism of the power tool based on the predetermined information; and a notification unit that notifies the diagnosis result by the deterioration diagnosis unit, wherein the predetermined information is information on the q-axis current supplied to the motor when the power tool rotates the output shaft until the tightening torque reaches a specified torque, with the output shaft of the power tool connected to the input unit.

17. The load device according to claim 16, further comprising: a storage unit for storing predetermined information acquired by the deterioration diagnosis unit; and an output unit for outputting the predetermined information stored in the storage unit.

18. The load device according to claim 16 or 17, further comprising a storage unit that stores information on the identification of the power tool that the deterioration diagnosis unit has identified as the subject of diagnosis, the diagnosis result by the deterioration diagnosis unit, and the date and time on which the deterioration diagnosis unit performed the diagnosis.

19. The load device according to any one of claims 1 to 18, further comprising a wireless communication unit configured to enable wireless communication with a server for managing the power tool or with other load devices.

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