Manufacturing method for impact tools and output blocks

Abstract

To provide a magnetostrictive sensor in an impact tool and increase strength of an output block against an impact occurring during an impact operation.SOLUTION: An impact tool includes a motor, an output block 8, a hammer, and a magnetostrictive sensor. The magnetostrictive sensor includes a magnetostrictive material part and a coil portion covering the magnetostrictive material part. The output block 8 includes a claw block 81 and a body block 82. The claw block 81 includes an anvil claw 812 against which a hammer claw collides. The claw block 81 has been subjected to quenching treatment. The body block 82 includes a thermally sprayed portion 821. In the thermally sprayed portion 821, a magnetostrictive material is thermally sprayed onto a surface to form the magnetostrictive material part. The body block 82 is coupled to the claw block 81.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure generally relates to a method for manufacturing an impact tool and an output block, and more particularly to an impact tool including a hammer and an output block having an anvil claw against which the hammer collides, and a method for manufacturing the output block used in this impact tool.

Background Art

[0002] The power tool (impact tool) described in Patent Document 1 includes a motor, an impact mechanism, an output shaft, and a torque measurement unit. The impact mechanism obtains power from the motor and generates an impact force. The output shaft holds a tip tool. The impact mechanism includes a hammer and an anvil. The output shaft is subjected to a rotational impact about the axis by the impact mechanism. The torque measurement unit measures the torque applied to the output shaft as a measured torque. The torque measurement unit is, for example, a magnetostrictive strain sensor (magnetostrictive sensor) capable of detecting torsional strain.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the power tool described in Patent Document 1, due to the impact of the impact operation accompanied by the generation of a rotational impact in the impact mechanism, a load is applied to the output block (here, the output block includes an anvil). Therefore, there has been a demand for improving the strength of the output block against such impacts.

[0005] This disclosure aims to provide an impact tool equipped with a magnetostrictive sensor and having increased strength of the output block against impacts generated during impact operation, and a method for manufacturing the output block used in this impact tool. [Means for solving the problem]

[0006] An impact tool according to one aspect of the present disclosure comprises a motor, an output block, a hammer, and a magnetostrictive sensor. The output block holds the tool tip. The hammer receives power from the motor and strikes the output block. The magnetostrictive sensor has a magnetostrictive material portion and a coil portion covering the magnetostrictive material portion. The hammer has a hammer body and a hammer claw connected to the hammer body. The output block has a claw block and a body block, The tip block and The claw block includes an anvil claw that the hammer claws strike. The claw block is heat-treated. The main body block includes a thermal sprayed portion. The thermal sprayed portion has a magnetostrictive material sprayed onto its surface to form the magnetostrictive material portion. The main body block is It is a separate component from the aforementioned claw block. It is connected to the aforementioned claw block. The tip block holds the tip tool and is a separate component from the main body block, and is connected to the main body block. The tip block is heat-treated.

[0007] A method for manufacturing an output block according to one aspect of this disclosure is a method for manufacturing an output block used in an impact tool to hold a tip tool. The output block comprises a claw block including an anvil claw, a main body block, A tip block that holds the aforementioned tip tool and is connected to the main body block, The manufacturing method comprises: a first step of heat-treating the claw block; a second step of thermal spraying a magnetostrictive material onto the surface of a thermal spray portion which is a predetermined part of the main body block to form a magnetostrictive material portion on the surface; and a third step of connecting the main body block to the claw block after the first and second steps. A fourth step of heat treatment of the tip block, and a fifth step of connecting the main body block to the tip block after the second and fourth steps, It holds. [Effects of the Invention]

[0008] This disclosure has the advantage of providing an impact tool that incorporates a magnetostrictive sensor while also increasing the strength of the output block against the shock generated during impact operation. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is an exploded view of the output block of an impact tool according to Embodiment 1, as seen from the rear. [Figure 2] Figure 2 is an exploded view of the output block of the same impact tool, viewed from the front. [Figure 3] Figure 3 is an exploded view of the output block, hammer, and transmission shaft of the same impact tool. [Figure 4] Figure 4 is a side cross-sectional view of the same impact tool. [Figure 5] Figure 5 is a side cross-sectional view of the main part of the impact tool shown above. [Figure 6] Figure 6 is a flowchart showing the manufacturing method of the output block of the impact tool described above. [Figure 7] Figure 7 is an exploded view of the output block of the impact tool according to Embodiment 2, as seen from the rear. [Figure 8] Figure 8 is a flowchart showing the manufacturing method of the output block of the impact tool described above. [Modes for carrying out the invention]

[0010] In each of the embodiments described below, the manufacturing methods for the impact tool and output block of this disclosure will be explained with reference to the drawings. However, each of the embodiments described below is only a part of the various embodiments of this disclosure. Each of the embodiments described below can be modified in various ways depending on the design, etc., as long as the objectives of this disclosure are achieved. In addition, the figures described in each of the embodiments described below are schematic diagrams, and the ratios of the size and thickness of each component in the figures do not necessarily reflect the actual dimensional ratios.

[0011] (Embodiment 1) (Summary) As shown in FIGS. 1 and 4, the impact tool 1 of the present embodiment includes a motor 3, an output block 8, a hammer 9, and a magnetostrictive sensor 5. The output block 8 holds the tip tool. The hammer 9 obtains power from the motor 3 and collides with the output block 8. The magnetostrictive sensor 5 has a magnetostrictive material portion 51 and a coil portion 52 that covers the magnetostrictive material portion 51. The hammer 9 has a hammer body 90 and a hammer claw 95 (see FIG. 3) connected to the hammer body 90. The output block 8 has a claw block 81 and a main body block 82. The claw block 81 includes an anvil claw 812 against which the hammer claw 95 collides. The claw block 81 is quenched. The main body block 82 includes a sprayed portion 821. The sprayed portion 821 has a magnetostrictive material sprayed on its surface to form the magnetostrictive material portion 51. The main body block 82 is connected to the claw block 81.

[0012] If the claw block 81 and the main body block 82 are made of one member, not only the main body block 82 but also the claw block 81 will be heated in the process of spraying the magnetostrictive material, and the effect of improving the impact resistance of the claw block 81 by the quenching process may decrease. On the other hand, in the present embodiment, by making the claw block 81 and the main body block 82 separate members, the impact resistance of the claw block 81 can be maintained.

[0013] Thus, in the present embodiment, it is possible to achieve both forming the magnetostrictive material portion 51 in the sprayed portion 821 of the main body block 82 and enhancing the impact resistance of the claw block 81 by the quenching process. That is, it is possible to provide an impact tool 1 that includes the magnetostrictive sensor 5 and has an increased strength of the output block 8 against the impact generated during the impact operation.

[0014] Also, in the impact tool ¹, the torque can be measured by the magnetostrictive sensor 5, and the motor 3 can be controlled based on the measured torque.

[0015] (Details) (1) Structure In the following description, the direction in which the claw block 81 of the output block 8 and the tip portion 823 described later are arranged side by side is defined as the front-rear direction. The tip portion 823 side when viewed from the claw block 81 is defined as the front, and the claw block 81 side when viewed from the tip portion 823 is defined as the rear. Also, in the following description, the direction in which the body portion 21 and the grip portion 22 described later are arranged side by side is defined as the vertical direction. The body portion 21 side when viewed from the grip portion 22 is defined as the upper side, and the grip portion 22 side when viewed from the body portion 21 is defined as the lower side. However, these definitions are not intended to define the usage direction of the impact tool 1.

[0016] The impact tool 1 of the present embodiment is a portable electric tool. As shown in FIG. 4, the impact tool 1 includes a housing 2, a motor 3, a transmission mechanism 4, an operation unit 24, a magnetostrictive sensor 5, a circuit unit 6, and a control unit 7. The transmission mechanism 4 includes an output block 8 and a hammer 9.

[0017] The housing 2 houses the motor 3, the transmission mechanism 4, the magnetostrictive sensor 5, the circuit unit 6, and the control unit 7. The housing 2 has a body portion 21, a grip portion 22, and a mounting portion 23. The shape of the body portion 21 is cylindrical. The grip portion 22 protrudes from the body portion 21. More specifically, the grip portion 22 protrudes from the side surface of the body portion 21. The tip of the grip portion 22 on the side opposite to the side connected to the body portion 21 is connected to the mounting portion 23.

[0018] A rechargeable battery pack is detachably attached to the mounting portion 23. The impact tool 1 operates using the battery pack as a power source. That is, the battery pack is a power source that supplies current to drive the motor 3. The battery pack is not a component of the impact tool 1. However, the impact tool 1 may include a battery pack. The battery pack includes a battery pack formed by connecting a plurality of secondary batteries (for example, lithium-ion batteries) in series, and a case that houses the battery pack.

[0019] The operating section 24 protrudes from the grip section 22. The operating section 24 receives input for controlling the rotation of the motor 3. In this disclosure, "rotation of the motor 3" refers to the rotation of the drive shaft 311 of the motor 3. The motor 3 can be switched on or off by pulling the operating section 24. The rotation speed of the motor 3 can also be adjusted by the amount of pull on the operating section 24. The greater the amount of pull, the faster the rotation speed of the motor 3. The control unit 7 rotates or stops the motor 3 and controls the rotation speed of the motor 3 according to the amount of pull on the operating section 24.

[0020] The tool tip is held in the output block 8. More specifically, the tool tip is detachable from the output block 8. The tool tip is mounted to the output block 8 via a chuck. However, the tool tip may also be mounted directly to the output block 8.

[0021] The output block 8 receives power from the motor 3 and rotates together with the cutting tool. The rotation speed of the cutting tool is controlled by controlling the rotation speed of the motor 3 through operation of the control unit 24.

[0022] The tip tool is not a component of the impact tool 1. However, the impact tool 1 may be equipped with a tip tool.

[0023] The cutting tool is, for example, a screwdriver bit. The cutting tool engages with the screw (bolt or screw, etc.) being worked on. By rotating the cutting tool while it is engaged with the screw, it becomes possible to tighten or loosen the screw.

[0024] In this embodiment, motor 3 is, for example, a brushless motor. Furthermore, motor 3 in this embodiment is a servo motor. The torque and rotational speed of motor 3 change according to the control by the control unit 7 (servo driver). More specifically, the control unit 7 controls the operation of motor 3 by feedback control, which adjusts the torque and rotational speed of motor 3 to approach target values. The control unit 7 can also control the operation of motor 3 based on the torque detected by the magnetostrictive sensor 5.

[0025] The transmission mechanism 4 has an impact mechanism 40. The impact tool 1 of this embodiment is an electric impact driver that performs screw tightening while performing an impact operation by the impact mechanism 40. In the impact operation, the impact mechanism 40 generates a striking force based on the power of the motor 3, and this striking force acts on the tip tool.

[0026] The transmission mechanism 4 preferably includes a planetary gear mechanism 48 in addition to the impact mechanism 40. The impact mechanism 40 includes a transmission shaft 41, a hammer 9, a return spring 43, an output block 8, and two steel balls 49. The rotation of the drive shaft 311 of the motor 3 is transmitted to the transmission 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 transmission shaft 41. The transmission shaft 41 is located between the motor 3 and the output block 8.

[0027] The hammer 9 is made of metal. The hammer 9 receives power from the motor 3 and moves relative to the output block 8, applying a striking force to the output block 8. As shown in Figure 3, the 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 transmission shaft 41 passes.

[0028] The hammer body 90 has two grooves 93 on the inner circumferential surface of the through hole 91. The transmission shaft 41 is cylindrical in shape. The transmission shaft 41 has two grooves 413 on its outer circumferential surface. The two grooves 413 are connected. Two steel balls 49 (see Figure 4) are sandwiched between the two grooves 93 and the two grooves 413. The two grooves 93, the two grooves 413 and the two steel balls 49 constitute a cam mechanism. As the two steel balls 49 move, the hammer 9 is movable in the axial direction of the transmission shaft 41 and is rotatable relative to the transmission shaft 41. As the hammer 9 moves forward or backward along the axial direction of the transmission shaft 41, the hammer 9 rotates relative to the transmission shaft 41.

[0029] The output block 8 is formed from metal. As shown in Figures 1 to 3, the output block 8 has a claw block 81 and a 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 body block 82 includes a thermal spray portion 821, a second connecting portion 822 and a tip portion 823.

[0030] The first connecting portion 811 has a cylindrical shape. That is, the first connecting portion 811 has a through hole in its center. The first connecting portion 811 is a boss having a gear-shaped groove 8110 on the inner surface of the through hole that engages with the spline shaft.

[0031] The two anvil claws 812 project radially from the first connecting portion 811. One of the two anvil claws 812 projects in the opposite direction to the other. The two anvil claws 812 are located in front of the hammer body 90 and face the hammer body 90.

[0032] The external shape of the thermal sprayed portion 821 of the main block 82 is cylindrical. The surface of the thermal sprayed portion 821 is covered with a magnetostrictive material portion 51 (see Figure 4). However, the magnetostrictive material portion 51 is not shown in Figures 1 to 3. The axial direction of the thermal sprayed portion 821 is along the front-rear direction. The first end (rear end) of the thermal sprayed portion 821 is connected to the second connecting portion 822. The second end (front end) of the thermal sprayed portion 821 is connected to the tip portion 823.

[0033] The second connecting portion 822 is connected to the first connecting portion 811. The second connecting portion 822 is a spline shaft that fits into the groove portion 8110 of the first connecting portion 811. The general shape of the second connecting portion 822 is cylindrical, and the shape of the second connecting portion 822 in a cross section perpendicular to its axis is gear-like.

[0034] The tip portion 823 has a cylindrical shape. The tip portion 823 has a through hole 8230 for connecting to a chuck.

[0035] As shown in Figure 3, the main body block 82 is connected to the claw block 81. As a result, the thermal spray section 821 protrudes forward from the claw block 81.

[0036] More specifically, the second connecting portion 822 of the main body block 82 is passed through the through hole in the center of the first connecting portion 811 and engages with the groove portion 8110. This connects the second connecting portion 822 to the first connecting portion 811. In other words, the main body block 82 is connected to the claw block 81.

[0037] It is preferable that the main body block 82 and the claw block 81 are connected by press-fitting. This reduces rattle between the main body block 82 and the claw block 81. By reducing rattle, energy transfer loss between the main body block 82 and the claw block 81 is reduced. Therefore, the impact received by the claw block 81 from the hammer 9 is more easily manifested as distortion in the magnetostrictive material portion 51 provided in the main body block 82, thereby improving the sensitivity of the magnetostrictive sensor 5.

[0038] Furthermore, the spline shape of the first connecting portion 811 and the second connecting portion 822 allows for a strong connection between the claw block 81 and the main body block 82.

[0039] As shown in Figures 4 and 5, the return spring 43 is positioned behind the hammer 9. In this embodiment, the return spring 43 is a conical coil spring. The hammer 9 receives a forward force from the return spring 43. The hammer 9 is rotatable relative to the return spring 43. The impact mechanism 40 further includes a ring 42 sandwiched between the hammer 9 and the return spring 43.

[0040] When the impact mechanism 40 is not performing an impact operation, the two hammer pawls 95 of the hammer 9 and the two anvil pawls 812 of the output block 8 are in contact in the rotational direction of the transmission shaft 41, and the hammer 9 and the output block 8 rotate together as a single unit. Therefore, at this time, the transmission shaft 41, the hammer 9, and the output block 8 rotate together as a single unit.

[0041] The impact mechanism 40 performs an impact operation when a torque condition related to the magnitude of the torque applied to the main body block 82 of the output block 8 (hereinafter referred to as load torque) is met. The impact operation is an operation in which a striking force is applied from the hammer 9 to the output block 8. In this embodiment, the torque condition is that the load torque is equal to or greater than a predetermined value. That is, as the load torque increases, the component of the force generated between the hammer 9 and the output block 8 that causes the hammer 9 to retract also increases. When the load torque is equal to or greater than a predetermined value, the hammer 9 retracts while compressing the return spring 43. As the hammer 9 retracts, the two hammer claws 95 of the hammer 9 move over the two anvil claws 812 of the output block 8, causing the hammer 9 to rotate. After that, the hammer 9 moves forward, receiving the return force from the return spring 43. Then, when the transmission shaft 41 has rotated approximately half a turn, the two hammer claws 95 of the hammer 9 collide with the side surfaces 8120 of the two anvil claws 812 of the output block 8. In the impact mechanism 40, the two hammer claws 95 of the hammer 9 collide with the two anvil claws 812 of the output block 8 each time the transmission shaft 41 rotates approximately half a turn. In other words, each time the transmission shaft 41 rotates approximately half a turn, the hammer 9 applies a striking force (rotational striking force) to the output block 8.

[0042] In this way, the impact mechanism 40 repeatedly collides with the hammer 9 and the output block 8. The torque generated by these collisions allows the screw to be tightened more strongly compared to when there are no collisions.

[0043] As shown in Figure 4, the impact tool 1 further includes a bearing 16. The bearing 16 is housed in the housing 2. The bearing 16 is in contact with the main body block 82 of the output block 8. More specifically, the bearing 16 is in contact with the portion of the main body block 82 in front of the thermal spray section 821 (the tip portion 823). The bearing 16 rotatably holds the output block 8.

[0044] As shown in Figure 5, the magnetostrictive sensor 5 includes a magnetostrictive material section 51, a coil section 52, and a coil bobbin 53.

[0045] The magnetostrictive material portion 51 is formed on the surface of the thermal spray portion 821. As the magnetostrictive material constituting the magnetostrictive material portion 51, for example, an iron-cobalt alloy, an iron-nickel alloy, or a nickel-based ferrite can be used.

[0046] The coil bobbin 53 is fixed to the housing 2. The coil bobbin 53 is located behind the bearing 16. The coil section 52 includes one or more coils wound around the coil bobbin 53. The coil section 52 surrounds the magnetostrictive material section 51.

[0047] When torque is applied to the output block 8, distortion occurs in the thermal spray portion 821 of the output block 8, and a corresponding distortion occurs in the magnetostrictive material portion 51. The magnetostrictive sensor 5 detects the change in the permeability of the magnetostrictive material portion 51 in response to the distortion of the magnetostrictive material portion 51 caused by the torque applied to the output block 8 using the coil portion 52, and outputs a voltage signal proportional to the distortion as the detection result.

[0048] The circuit unit 6 (see Figure 4) includes, for example, a substrate and an electrical circuit mounted on the substrate. The circuit unit 6 is electrically connected to the coil unit 52. The circuit unit 6 supplies current to the coil unit 52. The circuit unit 6 also measures the strain of the output block 8. Specifically, the circuit unit 6 acquires a voltage signal from the coil unit 52 that is proportional to the strain generated in the output block 8 and the magnetostrictive material unit 51, and calculates the strain of the output block 8 based on the voltage signal.

[0049] (2) Manufacturing method Next, a method for manufacturing the output block 8 will be described with reference to Figure 6. Note that the flowchart shown in Figure 6 is merely one example of the manufacturing method according to this disclosure, and the order of processing may be changed as appropriate, or processing may be added or omitted as appropriate.

[0050] First, the molded claw block 81 and body block 82 are subjected to a quenching treatment (step ST1). Next, the claw block 81 and body block 82 are subjected to a tempering treatment (step ST2). The quenching temperature in the quenching treatment is higher than the tempering temperature in the tempering treatment.

[0051] Next, magnetostrictive material is sprayed onto the sprayed portion 821 of the main block 82 (step ST3). In other words, heated magnetostrictive material is sprayed onto the sprayed portion 821 and solidified to form a film of magnetostrictive material on the surface of the sprayed portion 821. This film is the magnetostrictive material portion 51 (see Figure 5). The surface temperature of the main block 82 while the magnetostrictive material is being sprayed is lower than the quenching temperature. Also, the surface temperature of the main block 82 while the magnetostrictive material is being sprayed is higher than the tempering temperature.

[0052] Next, the claw block 81 is connected to the main body block 82 (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.

[0053] Through the above process, output block 8 is manufactured.

[0054] In the process of thermal spraying magnetostrictive material, the component to which the magnetostrictive material is sprayed becomes hot, which can cause annealing and reduce the mechanical strength of the component. Therefore, in this embodiment, the claw block 81 and the main body block 82 are made into separate components, and in the process of thermal spraying the magnetostrictive material, the magnetostrictive material is sprayed only onto the main body block 82. As a result, a reduction in the mechanical strength of the claw block 81 can be avoided. In particular, since the claw block 81 contains (two) anvil claws 812 that collide with the hammer 9, it requires a higher mechanical strength than the main body block 82. In this embodiment, the mechanical strength of the claw block 81 can be ensured, and the reliability of the impact tool 1 can be increased.

[0055] Furthermore, if the surface of the output block 8 is carburized, the possibility of the carburized layer on the surface of the claw block 81 being altered by heat during the process of thermal spraying the magnetostrictive material can be reduced.

[0056] Furthermore, if the main body block 82 is subjected to a heat treatment after being sprayed with magnetostrictive material, the heat treatment may alter the magnetostrictive material portion 51, potentially impairing the function of the magnetostrictive sensor 5 that detects the strain of the output block 8. In contrast, in this embodiment, the function of the magnetostrictive sensor 5 can be maintained by spraying the magnetostrictive material onto the main body block 82 after the heat treatment.

[0057] Thus, the manufacturing method of the output block 8 in this embodiment is a method for manufacturing an output block 8 used in an impact tool 1 to hold the tip tool. The manufacturing method includes a first step (step ST1) of quenching a claw block 81 including an anvil claw 812. The manufacturing method further includes a second step (step ST3) of spraying a magnetostrictive material onto the surface of a thermal spray portion 821, which is a predetermined part of the main body block 82, to form a magnetostrictive material portion 51 on the surface. The manufacturing method further includes a third step (step ST4) of connecting the main body block 82 with the claw block 81. After the first and second steps are carried out, the third step is carried out. More specifically, after the quenching treatment in the first step is completed and the tempering treatment is also completed, the third step is carried out.

[0058] (Modified version of Embodiment 1) The following are examples of modifications of Embodiment 1. These modifications may be implemented by combining them as appropriate.

[0059] The output block 8 may have other structures in place of or in addition to the through-hole 8230 as a structure for connecting to a chuck or tip tool.

[0060] In Embodiment 1, the claw block 81 and the main body block 82 are connected with the main body block 82 inserted inside the claw block 81. However, the connection is not limited to this, and the claw block 81 may be connected with the claw block 81 inserted inside the main body block 82. Alternatively, the claw block 81 and the main body block 82 may be connected without insertion. For example, they may be connected by a projection extending from one of the claw block 81 and the main body block 82 being held by the other.

[0061] It is not essential that the first connecting portion 811 and the second connecting portion 822 have a spline shape. For example, the first connecting portion 811 and the second connecting portion 822 may be connected by inserting the second connecting portion 822, which has a cylindrical external shape, into the cylindrical first connecting portion 811.

[0062] The number of anvil claws 812 is not limited to two; it may be one or three or more. The number of hammer claws 95 is not limited to two; it may be one or three or more.

[0063] In the manufacturing method of the output block 8, the step of heat-treating the main block 82 is not essential.

[0064] (Embodiment 2) The output block 8A of the impact tool according to Embodiment 2 will be described below with reference to Figures 7 and 8. Components similar to those in Embodiment 1 are denoted by the same reference numerals and their description is omitted.

[0065] (1) Structure As shown in Figure 7, the output block 8A of this embodiment further includes a tip block 83. The tip block 83 holds the tip tool. The tip block 83 is connected to the main body block 82A. The tip block 83 is heat-treated.

[0066] In other words, the output block 8A includes a claw block 81, a main body block 82A, and a tip block 83. The configuration of the claw block 81 is the same as in Embodiment 1.

[0067] The main body block 82A has a thermal spray section 821, a second connecting section 822, and a third connecting section 824. The tip block 83 has a tip section 831 and a fourth connecting section 832.

[0068] The axial direction of the thermal spray section 821 is aligned with the front-rear direction. The first end (rear end) of the thermal spray section 821 is connected to the second connecting section 822. The second end (front end) of the thermal spray section 821 is connected to the third connecting section 824.

[0069] The third connecting portion 824 is connected to the fourth connecting portion 832. The third connecting portion 824 is a spline shaft that fits into the groove portion 8320 of the fourth connecting portion 832. The general shape of the third connecting portion 824 is cylindrical, and the shape of the third connecting portion 824 in a cross section perpendicular to its axis is gear-like.

[0070] The tip block 83 has a cylindrical shape. The tip portion 831 of the tip block 83 has a configuration corresponding to the tip portion 823 of Embodiment 1. The tip portion 831 has a cylindrical shape. The tip portion 831 is connected to the tool tip via a chuck. The tip portion 831 has a through hole 8310 for connecting to the chuck.

[0071] The fourth connecting portion 832 has a cylindrical shape. That is, the fourth connecting portion 832 has an opening in the center. The fourth connecting portion 832 is a boss having a gear-shaped groove 8320 on the inner surface of the opening that engages with the spline shaft (third connecting portion 824). The tip portion 831 and the fourth connecting portion 832 are connected in the front-rear direction.

[0072] The main body block 82A is connected to the tip block 83. More specifically, the third connecting portion 824 of the main body block 82A is inserted into the central opening of the fourth connecting portion 832 and engages with the groove portion 8320. This connects the third connecting portion 824 to the fourth connecting portion 832. In other words, the main body block 82A is connected to the tip block 83. As a result, the tip portion 831 protrudes forward from the main body block 82A.

[0073] It is preferable that the main body block 82A and the tip block 83 are connected by press-fitting. This reduces rattle between the main body block 82A and the tip block 83.

[0074] Also, similar to Embodiment 1, the main body block 82A is connected to the claw block 81.

[0075] (2) Manufacturing method Next, a method for manufacturing output block 8A will be described with reference to Figure 8. Note that the flowchart shown in Figure 8 is merely one example of the manufacturing method according to this disclosure, and the order of processing may be changed as appropriate, or processing may be added or omitted as appropriate.

[0076] First, the formed claw block 81, body block 82A, and tip block 83 are subjected to a quenching treatment (step ST1). Next, the claw block 81, body block 82A, and tip block 83 are subjected to a tempering treatment (step ST2). The quenching temperature in the quenching treatment is higher than the tempering temperature in the tempering treatment.

[0077] Next, magnetostrictive material is sprayed onto the thermal spray area 821 of the main block 82A (step ST3). The surface temperature of the main block 82A while the magnetostrictive material is being sprayed is lower than the quenching temperature. Also, the surface temperature of the main block 82A while the magnetostrictive material is being sprayed is higher than the tempering temperature.

[0078] Next, the claw block 81 is connected to the main body block 82A, and the tip block 83 is connected to the main body block 82A (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. Also, the third connecting portion 824 of the main body block 82A is press-fitted into the fourth connecting portion 832 of the tip block 83.

[0079] Through the above process, output block 8A is manufactured.

[0080] In this embodiment, the main body block 82A and the tip block 83 are separate components, and in the process of thermal spraying the magnetostrictive material, the magnetostrictive material is sprayed only onto the main body block 82A. Therefore, a decrease in the mechanical strength of the tip block 83 can be avoided. In particular, since the tip block 83 is configured to hold the tip tool, it is subjected to force directly from the tip tool and requires a higher mechanical strength than that required for the main body block 82A. In this embodiment, the mechanical strength of the tip block 83 can be ensured, and the reliability of the impact tool can be improved.

[0081] Thus, the manufacturing method of the output block 8A in this embodiment further includes, in addition to the first to third steps of the manufacturing method of the output block 8 in Embodiment 1, a fourth step of quenching the tip block 83 and a fifth step of connecting the main body block 82A to the tip block 83. The fifth step is performed after the second and fourth steps have been carried out. More specifically, the fifth step is performed after the quenching in the fourth step, as well as the tempering process, has been completed. The tip block 83 holds the tip tool. The tip block 83 is connected to the main body block 82A.

[0082] (Modified version of Embodiment 2) The following are examples of modifications of Embodiment 2. These modifications may be implemented by combining them as appropriate. Furthermore, the modifications of Embodiment 1 described above can also be applied to Embodiment 2 as appropriate.

[0083] In Embodiment 2, the main body block 82A and the tip block 83 are connected with the main body block 82A inserted inside the tip block 83. However, the connection is not limited to this, and the tip block 83 may be connected with the main body block 82A inserted inside the tip block 83. Alternatively, the main body block 82A and the tip block 83 may be connected without insertion. For example, they may be connected by a projection extending from one of the main body block 82A and the tip block 83 being held by the other.

[0084] It is not essential that the third connecting portion 824 and the fourth connecting portion 832 have a spline shape. For example, the third connecting portion 824 and the fourth connecting portion 832 may be connected by inserting the cylindrical fourth connecting portion 832, which has an external cylindrical shape, into the cylindrical third connecting portion 824.

[0085] (summary) Based on the embodiments described above, the following aspects are disclosed.

[0086] An impact tool (1) according to the first embodiment comprises a motor (3), output blocks (8, 8A), a hammer (9), and a magnetostrictive sensor (5). The output blocks (8, 8A) hold the tip tool. The hammer (9) receives power from the motor (3) and collides with the output blocks (8, 8A). The magnetostrictive sensor (5) has a magnetostrictive material part (51) and a coil part (52) that covers the magnetostrictive material part (51). The hammer (9) has a hammer body (90) and hammer claws (95) connected to the hammer body (90). The output blocks (8, 8A) have claw blocks (81) and body blocks (82, 82A). The claw block (81) includes an anvil claw (812) into which the hammer claw (95) collides. The claw block (81) is hardened. The main body block (82, 82A) includes a thermal spray section (821). The thermal spray section (821) has a magnetostrictive material sprayed onto its surface to form a magnetostrictive material section (51). The main body block (82, 82A) is connected to the claw block (81).

[0087] According to the above configuration, it is possible to simultaneously form a magnetostrictive material portion (51) on the thermal spray portion (821) of the main body block (82, 82A) and to enhance the impact resistance of the claw block (81) by hardening. In other words, it is possible to provide an impact tool (1) that is equipped with a magnetostrictive sensor (5) while increasing the strength of the output block (8, 8A) against the impact generated during impact operation.

[0088] Furthermore, in the impact tool (1) according to the second embodiment, in the first embodiment, the output block (8A) further comprises a tip block (83). The tip block (83) holds the tip tool. The tip block (83) is connected to the main block (82A). The tip block (83) is hardened.

[0089] According to the above configuration, the strength of not only the claw block (81) but also the tip block (83) can be increased.

[0090] Furthermore, in the impact tool (1) according to the third embodiment, the main body block (82A) and the tip block (83) are connected by press-fitting, as in the second embodiment.

[0091] According to the above configuration, rattling between the main body block (82A) and the tip block (83) is suppressed, thereby reducing energy transfer loss between the main body block (82A) and the tip block (83).

[0092] Furthermore, in the impact tool (1) according to the fourth embodiment, in any one of the first to third embodiments, the main body block (82, 82A) and the claw block (81) are connected by press-fitting.

[0093] According to the above configuration, rattle between the main body block (82, 82A) and the claw block (81) is suppressed, thereby reducing energy transfer loss between the main body block (82, 82A) and the claw block (81). In addition, this makes it easier for the impact received by the claw block (81) to manifest as distortion in the magnetostrictive material part (51), thereby improving the sensitivity of the magnetostrictive sensor (5).

[0094] The configurations other than those in the first embodiment are not essential to the impact tool (1) and can be omitted as appropriate.

[0095] Furthermore, the manufacturing method for the output block (8, 8A) according to the fifth embodiment is a manufacturing method for the output block (8, 8A) used in an impact tool (1) to hold the tip tool. The output block (8, 8A) comprises a claw block (81) including an anvil claw (812) and a main body block (82, 82A). The manufacturing method comprises a first step of heat treatment of the claw block (81), a second step of thermal spraying a magnetostrictive material onto the surface of a thermal spray portion (821) which is a predetermined part of the main body block (82, 82A) to form a magnetostrictive material portion (51) on the surface, and a third step of connecting the main body block (82, 82A) to the claw block (81) after the first and second steps.

[0096] According to the above configuration, it is possible to provide an impact tool (1) that is equipped with a magnetostrictive sensor (5) while increasing the strength of the output blocks (8, 8A) against the shock generated during impact operation.

[0097] Furthermore, in the manufacturing method of the output block (8A) according to the sixth embodiment, the output block (8A) further comprises a tip block (83) in the fifth embodiment. The tip block (83) holds the tip tool and is connected to the main body block (82A). The manufacturing method further comprises a fourth step of heat treatment of the tip block (83), and a fifth step of connecting the main body block (82A) to the tip block (83) after the second and fourth steps.

[0098] According to the above configuration, the strength of not only the claw block (81) but also the tip block (83) can be increased. [Explanation of Symbols]

[0099] 1. Impact Tools 3 motors 5. Magnetostrictive sensor 8, 8A output block 9 Hammer 51 Magnetostrictive material section 52 Coil section 81 Claw Block 82, 82A Main Block 83 Tip block 90 Hammer body 95 Hammer Claws 812 Anvil Claw 821 Thermal spray section

Claims

1. Motor and, An output block that holds the tip tool, A hammer that receives power from the motor and collides with the output block, A magnetostrictive sensor comprising a magnetostrictive material portion and a coil portion covering the magnetostrictive material portion, The hammer comprises a hammer body and hammer claws connected to the hammer body. The output block described above is: A hardened jaw block including an anvil jaw into which the hammer jaws collide, A thermal sprayed portion is formed on the surface by thermal spraying a magnetostrictive material, and the main body block is a separate component from the claw block and is connected to the claw block, It has a tip block that holds the tip tool and is a separate component from the main body block, and is connected to the main body block, The aforementioned tip block is heat-treated. Impact tools.

2. The main body block and the tip block are connected by press-fitting, The impact tool according to claim 1.

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

4. A method for manufacturing an output block used in an impact tool to hold a tip tool, wherein the output block comprises a claw block including an anvil claw, a main body block, and a tip block that holds the tip tool and is connected to the main body block, The first step is to heat-treat the aforementioned claw block, A second step involves spraying a magnetostrictive material onto the surface of a predetermined part of the main body block, which is the thermal sprayed portion, to form a magnetostrictive material portion on the surface. After the first and second steps, a third step is taken to connect the main body block to the claw block, A fourth step involves heat treatment of the aforementioned tip block, The process includes a fifth step, after the second and fourth steps, of connecting the main body block to the tip block. A method for manufacturing an output block.

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