Impact tool and method for manufacturing an output block

Abstract

The object of the present disclosure is to provide an impact tool having a magnetostrictive sensor, and to increase the mechanical strength of an output block to be sufficient for the output block to withstand an impact caused by an impact operation. The impact tool includes a motor, an output block (8), a hammer, and a magnetostrictive sensor. The magnetostrictive sensor includes a magnetostrictive member and a coil portion covering the magnetostrictive member. The output block (8) includes a jaw block (81) and a main body block (82). The jaw block (81) includes anvil jaws (812) for the hammer jaws to strike. The jaw block (81) has been subjected to a quenching treatment. The main body block (82) includes a thermal spray portion (821) and is coupled to the jaw block (81). The surface of the thermal spray portion (821) includes a magnetostrictive member made of a magnetostrictive material.

Description

Technical Field

[0001] This disclosure generally relates to an impact tool and a method for manufacturing an output block. More specifically, this disclosure relates to an impact tool and a method for manufacturing an output block used in such an impact tool, the impact tool comprising a hammer and an output block comprising an anvil for impact by the hammer. Background Technology

[0002] Japanese Patent Application Publication No. 2021-070108 discloses an electric tool (impact tool) comprising a motor, an impact mechanism, an output shaft, and a torque measuring unit. The impact mechanism receives power from the motor to generate an impact force. The end of the tool is held on the output shaft. The impact mechanism includes a hammer and an anvil. The output shaft is subjected to rotational impact about its axis by the impact mechanism. The torque measuring unit measures the torque applied to the output shaft as the measured torque. The torque measuring unit may be, for example, a magnetostrictive strain sensor (magnetostrictive sensor) capable of detecting torsional strain. Summary of the Invention

[0003] The problem the invention aims to solve

[0004] In the power tool disclosed in Japanese Patent Application Publication No. 2021-070108, a load is applied to the output block (which in this case includes an anvil) by an impact mechanism through an impact operation involving the generation of rotational impact. Therefore, the output block sometimes needs to have its mechanical strength sufficiently increased to withstand such impact.

[0005] Therefore, the object of the present invention is to provide an impact tool including a magnetostrictive sensor and an output block, and also to provide a method for manufacturing the output block used in such an impact tool, wherein the mechanical strength of the output block is increased to a level sufficient to enable the output block to withstand impacts caused by impact operations.

[0006] Solution for solving the problem

[0007] The impact tool according to a first aspect of this disclosure includes a motor, an output block, a hammer, and a magnetostrictive sensor. An end tool is held on the output block. The hammer receives power from the motor and impacts the output block. The magnetostrictive sensor includes a magnetostrictive member and a coil portion covering the magnetostrictive member. The hammer includes a hammer body and a hammer claw connected to the hammer body. The output block includes a claw block and a body block. The claw block includes an anvil for impact by the hammer claw. The claw block has been hardened. The body block includes a thermally sprayed portion and is coupled to the claw block. The surface of the thermally sprayed portion includes a magnetostrictive member made of a magnetostrictive material.

[0008] In the impact tool according to the second aspect of this disclosure, which can be implemented in conjunction with the first aspect, the output block further includes an end block. The end tool is held on the end block. The end block is coupled to the body block. The end block has undergone hardening treatment.

[0009] In the impact tool according to the third aspect of this disclosure, which can be implemented in conjunction with the second aspect, the body block and the end block are connected to each other by press fit.

[0010] In the fourth impact tool according to the disclosure, which can be implemented in combination with any of the first to third aspects, the body block and the claw block are connected to each other by press-fitting.

[0011] A method for manufacturing an output block according to a fifth aspect of this disclosure is designed to manufacture an output block used in impact tools to hold an end tool. The output block includes: a claw block, which includes an anvil; and a body block. The method includes a first step, a second step, and a third step. The first step includes subjecting the claw block to a quenching treatment. The second step includes thermally spraying a magnetostrictive material onto the surface of a thermally sprayed portion forming a predetermined portion of the body block, thereby forming a magnetostrictive member on the surface. The third step includes joining the body block and the claw block together after the first and second steps have been performed.

[0012] In a method for manufacturing an output block according to a sixth aspect of this disclosure, which can be implemented in conjunction with the fifth aspect, the output block further includes an end block. An end tool is held on the end block and is to be coupled to a body block. The method further includes: a fourth step comprising subjecting the end block to a quenching treatment; and a fifth step comprising coupling the body block to the end block after the second and fourth steps have been performed.

[0013] The effects of the invention

[0014] This disclosure achieves the advantage of providing an impact tool comprising a magnetostrictive sensor and an output block, wherein the mechanical strength of the output block is increased to a level sufficient to enable the output block to withstand impacts caused by impact operations. Attached Figure Description

[0015] Figure 1 This is an exploded perspective view of the output block of the impact tool according to the first embodiment, viewed from the rear side at an angle.

[0016] Figure 2 This is an exploded perspective view of the impact tool's output block, viewed from the front side at an angle.

[0017] Figure 3 It is an exploded 3D view of the impact tool's output block, hammer, and drive shaft;

[0018] Figure 4 This is a side cross-sectional view of the impact tool;

[0019] Figure 5 This is a side cross-sectional view of the main parts of the impact tool;

[0020] Figure 6 This is a flowchart illustrating the process of manufacturing the output block of an impact tool;

[0021] Figure 7 This is an exploded perspective view of the output block of the impact tool according to the second embodiment, viewed from the rear side at an angle; and

[0022] Figure 8 This is a flowchart illustrating the process of manufacturing the output block of an impact tool. Detailed Implementation

[0023] Exemplary embodiments of the impact tool and method for manufacturing the output block according to the present disclosure will now be described with reference to the accompanying drawings. Note that the embodiments described below are merely exemplary embodiments among the various embodiments of the present disclosure and should not be construed as limiting. Rather, the exemplary embodiments can be readily modified in various ways depending on design choices or any other factors without departing from the scope of the present disclosure. The drawings referenced in the following description of the embodiments are schematic representations. Therefore, the ratios of the dimensions (including thickness) of the corresponding components shown in the drawings do not always reflect their actual dimensional ratios.

[0024] (First Implementation)

[0025] (Overview)

[0026] like Figure 1 and Figure 4 As shown, the impact tool 1 according to an exemplary embodiment includes a motor 3, an output block 8, a hammer 9, and a magnetostrictive sensor 5. The output block 8 holds the end tool. The hammer 9 receives power from the motor 3 and impacts the output block 8. The magnetostrictive sensor 5 includes a magnetostrictive member 51 and a coil portion 52 covering the magnetostrictive member 51. The hammer 9 includes a hammer body 90 and a hammer claw 95 connected to the hammer body 90 (see [link to documentation]). Figure 3 The output block 8 includes a claw block 81 and a main body block 82. The claw block 81 includes an anvil 812 for impact by the hammer claw 95. The claw block 81 has been hardened. The main body block 82 includes a thermally sprayed part 821 and is connected to the claw block 81. The surface of the thermally sprayed part 821 includes a magnetostrictive member 51 made of magnetostrictive material.

[0027] If the claw block 81 and the main body block 82 are formed as a single integral component, then during the thermal spraying of the magnetostrictive material, not only the main body block 82 but also the claw block 81 will be heated, which may reduce the effect of increasing the impact resistance of the claw block 81 achieved by the quenching process. Conversely, according to this embodiment, the claw block 81 and the main body block 82 are set as two independent components, thereby maintaining the impact resistance of the claw block 81.

[0028] Therefore, this embodiment can form a magnetostrictive member 51 on the thermally sprayed portion 821 of the main body block 82, and simultaneously increase the impact resistance of the claw block 81 through quenching treatment. In other words, this makes it possible to provide an impact tool 1 including a magnetostrictive sensor 5 and an output block 8, wherein the mechanical strength of the output block 8 is increased to a level sufficient to allow the output block 8 to withstand the impact caused by the impact operation.

[0029] Furthermore, the impact tool 1 can enable the magnetostrictive sensor 5 to measure torque and control the motor 3 based on the measured torque.

[0030] (detail)

[0031] (1) Structure

[0032] In the following description, the orientation of the claw block 81 and its end portion 823 (described later) of the output block 8 arranged side by side will be defined as the "front-to-back direction," where the end portion 823 is considered to be located in front of the claw block 81, and the claw block 81 is considered to be located in rear of the end portion 823. Furthermore, in the following description, the orientation of the cylinder portion 21 and the gripping portion 22 (described later) arranged one on top of the other will be defined as the "up-down direction," where the cylinder portion 21 is considered to be located above the gripping portion 22, and the gripping portion 22 is considered to be located below the cylinder portion 21. However, these definitions should not be construed as limiting the direction in which the impact tool 1 should be used.

[0033] The impact tool 1 according to this embodiment is a portable power tool. For example... Figure 4 As shown, the impact tool 1 includes a housing 2, a motor 3, a transmission mechanism 4, an operating component 24, a magnetostrictive sensor 5, a circuit section 6, and a control unit 7. The transmission mechanism 4 includes an output block 8 and a hammer 9.

[0034] The housing 2 houses the motor 3, the transmission mechanism 4, the magnetostrictive sensor 5, the circuit section 6, and the control unit 7. The housing 2 includes a cylindrical portion 21, a gripping portion 22, and an attachment portion 23. The cylindrical portion 21 is cylindrical. The gripping portion 22 protrudes from the cylindrical portion 21. More specifically, the gripping portion 22 protrudes from the side of the cylindrical portion 21. The end portion of the gripping portion 22 opposite to the portion connected to the cylindrical portion 21 is connected to the attachment portion 23.

[0035] A rechargeable battery pack is removably attached to attachment portion 23. The impact tool 1 is powered by the battery pack. That is, the battery pack is a power source that supplies current for driving the motor 3. In this embodiment, the battery pack is not a constituent element of the impact tool 1. However, this is merely an example and should not be construed as limiting. Alternatively, the impact tool 1 may include a battery pack as one of its constituent elements. The battery pack includes an assembled battery formed by connecting multiple secondary batteries (such as lithium-ion batteries) in series and a housing that houses the assembled battery.

[0036] The operating member 24 protrudes from the gripper 22. The operating member 24 receives operating commands for controlling the rotation of the motor 3. As used herein, "rotation of the motor 3" refers to the rotation of the drive shaft 311 of the motor 3. The on / off state of the motor 3 can be switched by pulling the operating member 24. Furthermore, the rotational speed of the motor 3 can be adjusted by a manipulation variable indicating how deeply the operating member 24 has been pulled. Specifically, the larger the manipulation variable, the higher the rotational speed of the motor 3. In addition, based on the manipulation variable indicating how deeply the operating member 24 has been pulled, the control unit 7 also starts or stops the motor 3 and controls the rotational speed of the motor 3.

[0037] The end effector is held by output block 8. More specifically, the end effector can be attached to and removed from output block 8. In this embodiment, the end effector is attached to output block 8 via a chuck. However, this is merely an example and should not be construed as limiting. Alternatively, the end effector can be directly attached to output block 8.

[0038] The output block 8 receives power from the motor 3 to rotate together with the end tool. Since the rotational speed of the motor 3 is controlled by operating the operating member 24, the rotational speed of the end tool is also controlled.

[0039] In this embodiment, the end tool is not a constituent element of the impact tool 1. However, the impact tool 1 may include the end tool as one of its constituent elements.

[0040] End tools can be, for example, screwdriver bits. The end tool is fitted into a fastening component (such as a bolt or screw) that is the target of the work. Tightening or loosening a screw can be performed by turning the end tool fitted into the screw.

[0041] The motor 3 according to this embodiment can be, for example, a brushless motor. Furthermore, the motor 3 according to this embodiment is a servo motor. The torque and rotational speed of the motor 3 are varied under the control of the control unit 7 (which is a servo driver). More specifically, the control unit 7 controls the operation of the motor 3 through feedback control to bring the torque and rotational speed of the motor 3 closer to the target values. Furthermore, the control unit 7 can control the operation of the motor 3 based on the torque detected by the magnetostrictive sensor 5.

[0042] The transmission mechanism 4 includes an impact mechanism 40. The impact tool 1 according to this embodiment is an electric impact screwdriver used to tighten screws while performing an impact operation using the impact mechanism 40. During the impact operation, the impact mechanism 40 generates an impact force based on the power of the motor 3 and applies the impact force to the end tool.

[0043] The transmission mechanism 4 preferably includes not only the impact mechanism 40 but also a planetary gear mechanism 48. The impact mechanism 40 includes a drive shaft 41, a hammer 9, a return spring 43, an output block 8, and two steel balls 49. The rotational power of the drive shaft 311 of the motor 3 is transmitted to the drive shaft 41 via the planetary gear mechanism 48. The transmission mechanism 4 transmits the torque of the motor 3 to the output block 8 via the drive shaft 41. The drive shaft 41 is installed between the motor 3 and the output block 8.

[0044] Hammer 9 is made of metal. Hammer 9 moves relative to output block 8 and applies an impact force to output block 8 when receiving power from motor 3. Figure 3 As shown, hammer 9 includes a hammer body 90 and two hammer claws 95. The hammer body 90 is disc-shaped. The two hammer claws 95 protrude from the front surface of the hammer body 90. The hammer body 90 has a through hole 91 through which the drive shaft 41 passes.

[0045] The hammer body 90 has two grooves 93 on the inner circumferential surface of the through hole 91. The drive shaft 41 is cylindrical. The outer circumferential surface of the drive shaft 41 has two grooves 413. The two grooves 413 are connected to each other. Two steel balls 49 (see...) Figure 4 The hammer 9 is sandwiched between two slots 93 and two slots 413. The two slots 93, two slots 413, and two steel balls 49 together form a cam mechanism. With the two steel balls 49 rolling, the hammer 9 can move and rotate relative to the drive shaft 41 along its axis. As the hammer 9 moves forward or backward along the axis of the drive shaft 41, it rotates relative to the drive shaft 41.

[0046] Output block 8 is made of metal. For example... Figures 1 to 3 As shown, the output block 8 includes a claw block 81 and a main body block 82. The claw block 81 corresponds to the so-called "anvil" of the impact tool 1. The claw block 81 includes a first connecting portion 811 and two anvil claws 812. The main body block 82 includes a thermal spraying portion 821, a second connecting portion 822, and an end portion 823.

[0047] The first connecting part 811 is cylindrical. That is, the first connecting part 811 has a through hole as its central hole. The first connecting part 811 is a boss with a through hole, and its inner surface has a gear-shaped groove 8110 to be assembled to a spline shaft.

[0048] Two anvils 812 protrude from the first connecting portion 811 and extend along the radius of the first connecting portion 811. One of the two anvils 812 protrudes toward the opposite end of the other anvil 812. The anvils 812 are located in front of the hammer body 90 and face the hammer body 90.

[0049] The thermally sprayed portion 821 of the main body block 82 is cylindrical in appearance. The surface of the thermally sprayed portion 821 is covered with a magnetostrictive member 51 (see...). Figure 4Note that in Figures 1 to 3 The magnetostrictive member 51 is omitted from the illustration. The axis of the thermal spraying section 821 is aligned with the front-to-back direction. The first end (rear end) of the thermal spraying section 821 is connected to the second connecting section 822. The second end (front end) of the thermal spraying section 821 is connected to the end section 823.

[0050] The second connecting part 822 is connected to the first connecting part 811. The second connecting part 822 is a spline shaft to be assembled into the groove 8110 of the first connecting part 811. The second connecting part 822 is generally cylindrical. When cut along a plane that intersects the central axis of the second connecting part 822 at a right angle, the second connecting part 822 is gear-shaped.

[0051] The end portion 823 is cylindrical in appearance. The end portion 823 has a through hole 8230 for connection to the chuck.

[0052] like Figure 3 As shown, the main body block 82 is connected to the claw block 81, so that the thermal spraying part 821 protrudes forward from the claw block 81.

[0053] More specifically, the second connecting portion 822 of the main body block 82 passes through the central through hole of the first connecting portion 811 to be fitted into the groove portion 8110. In this way, the second connecting portion 822 is connected to the first connecting portion 811. That is, the main body block 82 is connected to the claw block 81.

[0054] The main body block 82 and the claw block 81 are preferably connected to each other by a press fitting. This reduces the backlash between the main body block 82 and the claw block 81, thereby reducing energy transfer losses between them. As a result, it makes it easier to represent the impact received by the claw block 81 from the hammer 9 as strain of the magnetostrictive member 51 provided for the main body block 82, thus helping to increase the sensitivity of the magnetostrictive sensor 5.

[0055] Furthermore, the first connecting part 811 and the second connecting part 822 are spline-shaped, thereby allowing the claw block 81 and the main body block 82 to be firmly connected to each other.

[0056] like Figure 4 and Figure 5 As shown, the return spring 43 is arranged behind the hammer 9. According to this embodiment, the return spring 43 is a conical helical spring. The hammer 9 receives a forward biasing force from the return spring 43. The hammer 9 can rotate relative to the return spring 43. The impact mechanism 40 also includes a ring 42 disposed between the hammer 9 and the return spring 43.

[0057] When the impact mechanism 40 is not performing an impact operation, the hammer 9 and the output block 8 rotate together while the two hammer claws 95 of the hammer 9 and the two anvil claws 812 of the output block 8 remain in contact with each other in the rotation direction of the drive shaft 41. Therefore, at this time, the drive shaft 41, the hammer 9, and the output block 8 rotate together.

[0058] When a torque condition is met regarding the magnitude of the torque applied to the main body block 82 of the output block 8 (hereinafter referred to as "load torque"), the impact mechanism 40 begins to perform an impact operation. The impact operation is the operation of applying an impact force from the hammer 9 to the output block 8. In this embodiment, the torque condition is the condition that the load torque becomes equal to or greater than a predetermined value. That is, as the load torque increases, the force component having the direction of retraction of the hammer 9 increases relative to the force generated between the hammer 9 and the output block 8. When the load torque increases above the predetermined value, the hammer 9 retracts while compressing the return spring 43. Furthermore, as the hammer 9 retracts, the hammer 9 rotates, and simultaneously the two hammer claws 95 of the hammer 9 pass over the two anvils 812 of the output block 8. Thereafter, the hammer 9 advances upon receiving a restoring force from the return spring 43. Then, when the drive shaft 41 rotates approximately half a revolution, the two hammer claws 95 of the hammer 9 strike the sides 8120 of the two anvils 812 of the output block 8. In the impact mechanism 40, whenever the drive shaft 41 rotates approximately half a revolution, the two hammer claws 95 of the hammer 9 strike the two anvil claws 812 of the output block 8. That is, whenever the drive shaft 41 rotates approximately half a revolution, the hammer 9 applies an impact force (rotational impact force) to the output block 8.

[0059] As can be seen, in this impact mechanism 40, the impact between the hammer 9 and the output block 8 occurs repeatedly. The torque generated by these impacts allows the screw to be tightened more securely than if there were no impact between the hammer 9 and the output block 8.

[0060] like Figure 4 As shown, the impact tool 1 also includes a bearing 16. The bearing 16 is housed in the housing 2. The bearing 16 contacts the main body block 82 of the output block 8. More specifically, the bearing 16 contacts the portion of the main body block 82 located in front of the thermal spraying section 821 (i.e., the end portion 823). The bearing 16 holds the output block 8 in a rotatable position.

[0061] like Figure 5 As shown, the magnetostrictive sensor 5 includes a magnetostrictive member 51, a coil portion 52, and a coil holder 53.

[0062] A magnetostrictive member 51 is formed on the surface of the thermally sprayed portion 821. Examples of magnetostrictive materials for the magnetostrictive member 51 include iron-cobalt based alloys, iron-nickel based alloys, and nickel-based ferrites.

[0063] The coil holder 53 is fixed to the housing 2. The coil holder 53 is arranged behind the bearing 16. The coil portion 52 includes one or more coils wound around the coil holder 53. The coil portion 52 surrounds the magnetostrictive member 51.

[0064] When a torque is applied to the output block 8, strain is induced in the thermally sprayed portion 821 of the output block 8, and thus strain is also induced in the magnetostrictive member 51. The magnetostrictive sensor 5 causes the coil portion 52 to detect the change in the permeability of the magnetostrictive member 51 caused by the strain induced in the magnetostrictive member 51 when the torque is applied to the output block 8, and outputs a voltage signal proportional to the strain as the detection result.

[0065] Loop section 6 (see) Figure 4 This includes, for example, a substrate and circuitry mounted on the substrate. The loop section 6 is electrically connected to the coil section 52. The loop section 6 allows current to flow through the coil section 52. Furthermore, the loop section 6 measures the strain of the output block 8. That is, the loop section 6 obtains a voltage signal from the coil section 52 that is proportional to the strain induced in the output block 8 and the magnetostrictive member 51, and calculates the strain of the output block 8 based on this voltage signal.

[0066] (2) Manufacturing method

[0067] Next, we will refer to Figure 6 This describes the method used to manufacture output block 8. Note that... Figure 6 The flowchart shown only illustrates an exemplary process of the manufacturing method according to this disclosure. Therefore, Figure 6 The processing steps shown can be performed in different orders as appropriate, additional processing steps can be performed as needed, or they can be omitted as appropriate. Figure 6 At least one of the processing steps shown.

[0068] First, the formed claw block 81 and main body block 82 are quenched (in step ST1). Next, the claw block 81 and main body block 82 are tempered (in step ST2). The quenching temperature in the quenching process is higher than the tempering temperature in the tempering process.

[0069] Next, the magnetostrictive material is thermally sprayed onto the thermally sprayed portion 821 of the main body block 82 (in step ST3). Specifically, by spraying and curing the heated magnetostrictive material onto the thermally sprayed portion 821, a magnetostrictive material film is formed on the surface of the thermally sprayed portion 821. This film is the magnetostrictive component 51 (see...). Figure 5 When the magnetostrictive material is thermally sprayed onto the main body block 82, the surface temperature of the main body block 82 is lower than the quenching temperature. Conversely, when the magnetostrictive material is thermally sprayed onto the main body block 82, the surface temperature of the main body block 82 is higher than the tempering temperature.

[0070] Next, the claw block 81 and the main body block 82 are connected to each other (in step ST4). More specifically, the second connecting portion 822 of the main body block 82 is inserted into the first connecting portion 811 of the claw block 81 by press fitting.

[0071] Output block 8 is manufactured by performing these processing steps.

[0072] In the thermal spraying of magnetostrictive material, the component targeted for the spraying of the magnetostrictive material is subjected to such a high temperature that annealing may occur, leading to a decrease in the mechanical strength of the component. Therefore, in this embodiment, the claw block 81 and the main body block 82 are configured as two independent components, and the thermal spraying of the magnetostrictive material involves spraying the magnetostrictive material only onto the main body block 82. This allows it to avoid a decrease in the mechanical strength of the claw block 81. In particular, the claw block 81 includes two anvil claws 812 for impacting the hammer 9, and therefore needs to have a higher mechanical strength than the main body block 82. This embodiment ensures sufficient mechanical strength for the claw block 81, thereby improving the reliability of the impact tool 1.

[0073] Furthermore, since the surface of the output block 8 has already undergone carburizing treatment, this can also reduce the possibility that the carburized layer on the surface of the claw block 81 may change its properties due to the heat in the thermal spraying magnetostrictive material processing step.

[0074] Furthermore, if the main body block 82 is subjected to quenching after the magnetostrictive material has been thermally sprayed onto it, the quenching process may alter the properties of the magnetostrictive member 51 and impair the ability of the magnetostrictive sensor 5 to detect the strain of the output block 8. Conversely, by thermally spraying the magnetostrictive material onto the main body block 82 after quenching, this embodiment allows the magnetostrictive sensor 5 to retain its capability.

[0075] As can be seen, the method for manufacturing the output block 8 according to this embodiment is designed to manufacture an output block 8 used in an impact tool 1 to hold the end tool. The manufacturing method includes a first step (step ST1), which includes subjecting a claw block 81, including an anvil 812, to a quenching process. The manufacturing method also includes a second step (step ST3), which includes thermally spraying a magnetostrictive material onto the surface of a thermally sprayed portion 821 forming a predetermined portion of the main body block 82, thereby forming a magnetostrictive member 51 on that surface. The manufacturing method also includes a third step (step ST4), which includes connecting the main body block 82 and the claw block 81 to each other. The third step is performed after the first and second steps have been performed. More specifically, the third step is performed only after not only the quenching process in the first step but also the tempering process has been completed.

[0076] (Variations of the first embodiment)

[0077] Next, variations of the first embodiment will be listed one by one. The variations described below can be used in combination as appropriate.

[0078] Instead of the through hole 8230, or in addition to the through hole 8230, the output block 8 may have an alternative structure for connection to a chuck or end tool.

[0079] In the first embodiment described above, when the main body block 82 is inserted inside the claw block 81, the claw block 81 and the main body block 82 are connected to each other. However, this is merely an example and should not be construed as limiting. Alternatively, the claw block 81 and the main body block 82 can be connected to each other with the claw block 81 inserted inside the main body block 82. Still alternatively, the claw block 81 and the main body block 82 can be connected to each other in ways other than insertion. For example, the claw block 81 and the main body block 82 can also be connected to each other by having a protrusion extending from one of the members selected from the group consisting of the claw block 81 and the main body block 82 held in place by another member selected from the group consisting of the claw block 81 and the main body block 82.

[0080] The first connecting part 811 and the second connecting part 822 do not necessarily have to be spline-shaped. For example, the first connecting part 811 and the second connecting part 822 can be connected to each other by inserting the cylindrical second connecting part 822 into the cylindrical first connecting part 811.

[0081] The number of anvils 812 provided does not necessarily have to be two; it can be one or more. Similarly, the number of hammers 95 provided does not necessarily have to be two; it can be one or more.

[0082] The quenching process performed on the main block 82 is not a necessary step in the method for manufacturing the output block 8.

[0083] (Second Implementation)

[0084] Next, we will refer to Figure 7 and Figure 8 The output block 8A of the impact tool according to the second embodiment is described below. In the following description, any constituent elements of this second embodiment having the same function as the counterpart of the first embodiment described above will be indicated by the same reference numerals as the counterpart, and their description will be omitted herein.

[0085] (1) Structure

[0086] like Figure 7 As shown, the output block 8A according to this embodiment also includes an end block 83. An end tool is held on the end block 83. The end block 83 is to be connected to the main body block 82A. The end block 83 has undergone hardening treatment.

[0087] That is, the output block 8A includes a claw block 81, a main body block 82A, and an end block 83. The claw block 81 has the same structure as the counterpart of the first embodiment described above.

[0088] The main body block 82A includes a thermal spraying section 821, a second connecting section 822, and a third connecting section 824. The end block 83 includes an end section 831 and a fourth connecting section 832.

[0089] The axis of the thermal spraying section 821 is aligned with the front-to-back direction. The first end (rear end) of the thermal spraying section 821 is connected to the second connecting section 822. The second end (front end) of the thermal spraying section 821 is connected to the third connecting section 824.

[0090] The third connecting part 824 is connected to the fourth connecting part 832. The third connecting part 824 is a spline shaft to be assembled into the groove 8320 of the fourth connecting part 832. The third connecting part 824 is generally cylindrical. When cut along a plane that intersects the central axis of the third connecting part 824 at a right angle, the third connecting part 824 is gear-shaped.

[0091] The end block 83 is cylindrical in appearance. The end portion 831 of the end block 83 has a structure corresponding to that of the end portion 823 according to the first embodiment. The end portion 831 is cylindrical in appearance. The end portion 831 is to be connected to the end tool via a chuck. The end portion 831 has a through hole 8310 for connection to the chuck.

[0092] The fourth connecting part 832 is cylindrical. That is, the fourth connecting part 832 has an opening as its central hole. The fourth connecting part 832 is a boss with an opening, and its inner surface has a gear-shaped groove 8320 to be fitted into the spline shaft (third connecting part 824). The end part 831 and the fourth connecting part 832 are connected to each other in the front-rear direction.

[0093] The main body block 82A is connected to the end block 83. More specifically, the third connecting portion 824 of the main body block 82A is inserted into the opening of the center hole that serves as the fourth connecting portion 832 and fitted into the groove 8320. In this way, the third connecting portion 824 is connected to the fourth connecting portion 832. That is, the main body block 82A is connected to the end block 83. As a result, the end portion 831 protrudes forward from the main body block 82A.

[0094] The main body block 82A and the end block 83 are preferably connected to each other by press fitting. This can reduce the tooth backlash between the main body block 82A and the end block 83.

[0095] In addition, the main body block 82A is also connected to the claw block 81 in the same manner as in the first embodiment described above.

[0096] (2) Manufacturing method

[0097] Next, we will refer to Figure 8 This describes the method used to manufacture output block 8A. Note that... Figure 8 The flowchart shown only illustrates an exemplary process of the manufacturing method according to this disclosure. Therefore, Figure 8 The processing steps shown can be performed in different orders as appropriate, additional processing steps can be performed as needed, or they can be omitted as appropriate. Figure 8 At least one of the processing steps shown.

[0098] First, the formed claw block 81, main body block 82A, and end block 83 are quenched (in step ST1). Next, the claw block 81, main body block 82A, and end block 83 are tempered (in step ST2). The quenching temperature in the quenching process is higher than the tempering temperature in the tempering process.

[0099] Next, the magnetostrictive material is thermally sprayed onto the thermally sprayed portion 821 of the main body block 82A (in step ST3). When the magnetostrictive material is thermally sprayed onto the main body block 82A, the surface temperature of the main body block 82A is lower than the quenching temperature. Furthermore, when the magnetostrictive material is thermally sprayed onto the main body block 82A, the surface temperature of the main body block 82A is higher than the tempering temperature.

[0100] Next, the claw block 81 and the main body block 82A are connected to each other, and the end block 83 and the main body block 82A are also connected to each other (in step ST4). More specifically, the second connecting portion 822 of the main body block 82A is press-fitted into the first connecting portion 811 of the claw block 81. Furthermore, the third connecting portion 824 of the main body block 82A is press-fitted into the fourth connecting portion 832 of the end block 83.

[0101] Output block 8A is manufactured by performing these processing steps.

[0102] In this embodiment, the main body block 82A and the end block 83 are configured as two independent components, and the thermal spraying of the magnetostrictive material involves spraying the magnetostrictive material only onto the main body block 82A. This allows for the avoidance of a decrease in the mechanical strength of the end block 83. In particular, the end block 83 is configured to hold the end tool and receive forces applied directly from the end tool, thus requiring a higher mechanical strength than the main body block 82A. This embodiment ensures sufficient mechanical strength for the end block 83, thereby improving the reliability of the impact tool 1.

[0103] As can be seen, in addition to the first, second, and third processing steps of the method for manufacturing output block 8 according to the first embodiment, the method for manufacturing output block 8A according to this embodiment also includes a fourth and a fifth step. The fourth step includes subjecting the end block 83 to a quenching treatment, and the fifth step includes attaching the main body block 82A to the end block 83. The fifth step is performed after the second and fourth steps have been performed. More specifically, the fifth step is performed only after not only the quenching treatment in the fourth step but also the tempering treatment has been completed. An end tool is held on the end block 83. The end block 83 is to be attached to the main body block 82A.

[0104] (Variation of the second embodiment)

[0105] Next, variations of the second embodiment will be listed one by one. The variations described below can be appropriately combined and used. Furthermore, the variations of the first embodiment described above are also appropriately applied to the second embodiment.

[0106] In the second embodiment described above, when the main body block 82A is inserted inside the end block 83, the main body block 82A and the end block 83 are connected to each other. However, this is merely an example and should not be construed as limiting. Alternatively, the main body block 82A and the end block 83 may be connected to each other when the end block 83 is inserted inside the main body block 82A. Still alternatively, the main body block 82A and the end block 83 may be connected to each other in ways other than insertion. For example, the main body block 82A and the end block 83 may also be connected to each other by having a protrusion extending from one of the members selected from the group consisting of the main body block 82A and the end block 83 held in place by another member selected from the group consisting of the main body block 82A and the end block 83.

[0107] The third connecting part 824 and the fourth connecting part 832 do not necessarily have to be spline-shaped. For example, the third connecting part 824 and the fourth connecting part 832 can be connected to each other by inserting the cylindrical fourth connecting part 832 into the cylindrical third connecting part 824.

[0108] (Summary)

[0109] The above-described embodiments and their variations may be specific implementations of the following aspects of this disclosure.

[0110] The impact tool (1) according to the first aspect includes a motor (3), output blocks (8, 8A), a hammer (9), and a magnetostrictive sensor (5). The end tool is held on the output blocks (8, 8A). The hammer (9) receives power from the motor (3) and strikes the output blocks (8, 8A). The magnetostrictive sensor (5) includes a magnetostrictive member (51) and a coil portion (52) covering the magnetostrictive member (51). The hammer (9) includes a hammer body (90) and a hammer claw (95) connected to the hammer body (90). The output blocks (8, 8A) include a claw block (81) and a main body block (82, 82A). The claw block (81) includes an anvil (812) for the hammer claw (95) to strike. The claw block (81) has been hardened. The main body block (82, 82A) includes a thermally sprayed portion (821) and is connected to the claw block (81). The surface of the thermal spraying section (821) includes a magnetostrictive member (51) made of a magnetostrictive material.

[0111] This construction allows for the formation of a magnetostrictive member (51) on the thermally sprayed portion (821) of the main body blocks (82, 82A), while simultaneously increasing the impact resistance of the claw blocks (81) through quenching treatment. In other words, this enables the provision of an impact tool (1) comprising a magnetostrictive sensor (5) and an output block (8, 8A), the mechanical strength of which is increased sufficiently to allow the output block (8, 8A) to withstand impacts caused by impact operations.

[0112] In the impact tool (1) according to the second aspect, which can be implemented in conjunction with the first aspect, the output block (8A) further includes an end block (83). The end tool is held on the end block (83). The end block (83) is coupled to the body block (82A). The end block (83) has been hardened.

[0113] This structure enables not only the mechanical strength of the claw block (81) to be increased, but also the mechanical strength of the end block (83).

[0114] In the impact tool (1) according to the third aspect, which can be implemented in conjunction with the second aspect, the main block (82A) and the end block (83) are connected to each other by press fit.

[0115] This structure can reduce the tooth gap between the main block (82A) and the end block (83), thereby reducing the energy transfer loss between the main block (82A) and the end block (83).

[0116] In the impact tool (1) according to the fourth aspect, which can be implemented in combination with any of the first to third aspects, the main body block (82, 82A) and the claw block (81) are connected to each other by press fit.

[0117] This structure can reduce the backlash between the main body blocks (82, 82A) and the claw blocks (81), thereby reducing energy transfer losses between the main body blocks (82, 82A) and the claw blocks (81). In addition, it also makes it easier to express the impact received by the claw blocks (81) as the strain of the magnetostrictive member (51), thereby helping to increase the sensitivity of the magnetostrictive sensor (5).

[0118] Note that the constituent elements according to the second to fourth aspects are not necessary constituent elements of the impact tool (1), but can be appropriately omitted.

[0119] The method for manufacturing output blocks (8, 8A) according to the fifth aspect is designed to manufacture output blocks (8, 8A) used in an impact tool (1) to hold the end tool. The output blocks (8, 8A) include: a claw block (81) including an anvil (812); and a body block (82, 82A). The method includes a first step, a second step, and a third step. The first step includes subjecting the claw block (81) to a quenching treatment. The second step includes thermally spraying a magnetostrictive material onto the surface of a thermally sprayed portion (821) forming a predetermined portion of the body block (82, 82A), thereby forming a magnetostrictive member (51) on that surface. The third step includes joining the body block (82, 82A) and the claw block (81) together after the first and second steps have been performed.

[0120] The method provides an impact tool (1) comprising a magnetostrictive sensor (5) and an output block (8, 8A) having increased mechanical strength to such an extent that the output block (8, 8A) can withstand impacts caused by impact operations.

[0121] In the method for manufacturing the output block (8A) according to the sixth aspect, which can be implemented in conjunction with the fifth aspect, the output block (8A) further includes an end block (83). The end block (83) holds an end tool and is to be coupled to the body block (82A). The method further includes: a fourth step comprising subjecting the end block (83) to a quenching process; and a fifth step comprising coupling the body block (82A) to the end block (83) after the second and fourth steps have been performed.

[0122] This method enables not only the mechanical strength of the claw block (81) to be increased, but also the mechanical strength of the end block (83).

[0123] List of reference numerals

[0124] 1. Impact tools

[0125] 3 motors

[0126] 5. Magnetostrictive Sensor

[0127] 8. 8A Output Block

[0128] 9 hammers

[0129] 51 Magnetostrictive Components

[0130] 52 Coil Section

[0131] 81 Claw Blocks

[0132] 82, 82A main blocks

[0133] 83 End Block

[0134] 90 Hammer Body

[0135] 95 Hammer Claw

[0136] 812 Anvil

[0137] 821 Thermal Spraying Department

Claims

1. An impact tool, comprising: motor; The output block is configured to retain the end tool; A hammer, configured to receive power from the motor and strike the output block; as well as A magnetostrictive sensor includes a magnetostrictive member and a coil portion covering the magnetostrictive member. The hammer includes a hammer body and a hammer claw connected to the hammer body. The output block includes: The claw block includes an anvil for impact by the hammer claw and is subjected to quenching treatment; A main body block, including a thermally sprayed section, the main body block being a component independent of the claw block and connected to the claw block, the surface of the thermally sprayed section including a magnetostrictive member made of a magnetostrictive material; and An end block, configured to hold the end tool, is a component independent of the body block and is coupled to the body block. The end block has been quenched.

2. The impact tool according to claim 1, wherein, The main block and the end block are connected to each other by press fitting.

3. The impact tool according to claim 1 or 2, wherein, The main body block and the claw block are connected to each other by press fitting.

4. A method for manufacturing an output block, the output block being used in an impact tool to hold an end-effector, the output block comprising: Claw block, which includes an anvil claw; Main block; And an end block configured to hold the end tool and attach to the body block, the method comprising: The first step includes subjecting the claw block to a quenching process; The second step includes thermally spraying a magnetostrictive material onto the surface of a thermally sprayed portion forming a predetermined portion of the main body block, thereby forming a magnetostrictive member on the surface. The third step includes connecting the main body block and the claw block to each other after the first and second steps have been performed; The fourth step includes subjecting the end block to quenching; and The fifth step includes attaching the body block to the end block after the second and fourth steps have been performed.

Images