Impact tool, spindle and spindle manufacturing method

Abstract

To provide an impact tool that can be reduced in time required in manufacturing, a spindle and a spindle manufacturing method.SOLUTION: An impact tool is provided with: a motor; a spindle which includes a sun gear that is rotated by the motor, at least three planetary gears that engage with the sun gear, an internal gear that engages with the planetary gears, a flange part which has a hole in an axial direction into which the sun gear is inserted and also has a slit part on which the planetary gears are mounted, at least on a side surface thereof, and a shaft part extending from the flange part to a front side in the axial direction, where the flange part is in a forged and molded state; a hammer held by the spindle; an anvil that is hit in a rotating direction by the hammer; a hammer case that stores the hammer and holds the anvil rotatably; a tip tool holding part formed in the anvil; and a coil spring that energizes the hammer toward the anvil.SELECTED DRAWING: Figure 7A

Description

[Technical field]

[0001] TECHNICAL FIELD The technology disclosed herein relates to impact tools, spindles and methods of manufacturing spindles. [Background technology]

[0002] 2. Description of the Related Art In the technical field relating to impact tools, an impact tool having a spindle, such as that disclosed in Patent Document 1, is known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-037561 Summary of the Invention [Problem to be solved by the invention]

[0004] In impact tools, there is a demand for reducing the time required to manufacture spindles. [Means for solving the problem]

[0005] This specification discloses an impact tool, which includes a motor, a sun gear rotated by the motor, at least three planetary gears meshing with the sun gear, an internal gear meshing with the planetary gears, a flange portion having a hole in the axial direction for inserting the sun gear and a slit portion on at least a side for attaching the planetary gear, a shaft portion extending forward in the axial direction from the flange portion, and the flange portion is formed by forging, a hammer held by the spindle, an anvil struck in the rotational direction by the hammer, a hammer case that houses the hammer and rotatably holds the anvil, a tool holder formed on the anvil, and a coil spring that biases the hammer toward the anvil. Effect of the Invention

[0006] The technology disclosed in this specification provides an impact tool, a spindle, and a method for manufacturing a spindle that can reduce the time required for manufacturing. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a front perspective view showing an impact tool according to an embodiment. [Diagram 2] FIG. 2 is a side view showing an upper portion of the impact tool according to the embodiment. [Diagram 3] FIG. 3 is a vertical cross-sectional view showing an upper portion of the impact tool according to the embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing an upper portion of the impact tool according to the embodiment. [Diagram 5] FIG. 5 is an exploded perspective view showing a main part of the impact tool according to the embodiment. [Figure 6] FIG. 6 is a bottom view showing the spindle according to the embodiment. [Figure 7A] FIG. 7A is a diagram that illustrates an example of grain flows in a solid portion of a spindle according to an embodiment. [Figure 7B] FIG. 7B is a diagram that illustrates an example of grain flows in a solid portion of the spindle according to the embodiment. [Figure 8] FIG. 8 is a side view of the spindle according to the embodiment. [Figure 9] FIG. 9 is a flowchart illustrating an example of a method for manufacturing a spindle according to the embodiment. [Figure 10] FIG. 10 is a diagram illustrating an example of a slug according to the embodiment. [Figure 11] FIG. 11 is a diagram showing an example of a forging die according to an embodiment. [Figure 12] FIG. 12 is a diagram illustrating an example of a mold placement step according to the embodiment. [Figure 13A] FIG. 13A is a diagram illustrating an example of a forging process according to the embodiment. [Figure 13B]FIG. 13B is a diagram illustrating an example of a forging process according to the embodiment. [Figure 14A] FIG. 14A is a diagram illustrating an example of a cutting step according to the embodiment. [Figure 14B] FIG. 14B is a diagram illustrating an example of a cutting step according to the embodiment. [Figure 14C] FIG. 14C is a diagram that illustrates an example of grain flows in a solid portion of a spindle according to an embodiment. [Figure 14D] FIG. 14D is a diagram that illustrates an example of grain flows in a solid portion of a spindle according to an embodiment. [Figure 15A] FIG. 15A is a diagram showing another example of the forging process according to the embodiment. [Figure 15B] FIG. 15B is a diagram showing another example of the forging process according to the embodiment. [Figure 16A] FIG. 16A is a diagram illustrating another example of the cutting step according to the embodiment. [Figure 16B] FIG. 16B is a diagram illustrating another example of the cutting step according to the embodiment. [Figure 16C] FIG. 16C is a diagram illustrating another example of grain flows in a solid portion of a spindle according to an embodiment. [Figure 16D] FIG. 16D is a diagram illustrating another example of grain flows in a solid portion of a spindle according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] In one or more embodiments, the impact tool may include a motor, a sun gear rotated by the motor, at least three planetary gears meshing with the sun gear, an internal gear meshing with the planetary gears, a flange portion having a hole in the axial direction for inserting the sun gear and a slit portion on at least a side for attaching the planetary gears, and a shaft portion extending axially forward from the flange portion, and the flange portion is formed by forging, a hammer held by the spindle, an anvil that is struck in the rotational direction by the hammer, a hammer case that houses the hammer and rotatably holds the anvil, a tool holder formed on the anvil, and a coil spring that biases the hammer toward the anvil.

[0009] In the above-described configuration, by using a spindle in which the flange portion is formed by forging, it is possible to reduce the time required to manufacture the impact tool.

[0010] In one or more embodiments, the flange portion may have a cut surface on at least a portion of its surface.

[0011] In the above-described configuration, the surface of the flange portion formed by forging can be appropriately cut as necessary, thereby improving the accuracy of the outer shape of the spindle.

[0012] In one or more embodiments, the spindle may further include a ball disposed between the spindle and the hammer, the spindle having a spindle groove in a shaft portion in which at least a portion of the ball is disposed.

[0013] With the above configuration, when manufacturing a spindle having a spindle groove in a shaft portion in which at least a portion of the ball is disposed, the time required for manufacturing can be shortened.

[0014] In one or more embodiments, the spindle may be formed using iron containing at least 0.13% and no more than 1.00% carbon and at least 0.90% chromium.

[0015] In the above-described configuration, it is possible to appropriately perform plastic deformation by forging, and it is possible to ensure the strength after deformation.

[0016] In one or more embodiments, the spindle may have grain flows formed in the flange portion by forging from the center toward the outside in the radial direction.

[0017] In the above configuration, grain flows are formed by forging in the flange portion of the spindle from the center toward the outside in the radial direction, so that appropriate strength can be ensured.

[0018] In one or more embodiments, the spindle may have a first flange connected to the shaft portion, a second flange positioned rearwardly and opposite the first flange, and a connecting portion axially connecting the first flange and the second flange.

[0019] With the above configuration, when manufacturing a spindle having a first flange, a second flange, and a connecting portion, the time required for manufacturing can be shortened.

[0020] In one or more embodiments, a plurality of the connecting portions may be arranged in the circumferential direction, and the planetary gears may be arranged between adjacent connecting portions in the portion sandwiched between the first flange and the second flange.

[0021] With the above configuration, when manufacturing a spindle in which planetary gears are arranged between adjacent connecting portions in the portion sandwiched between the first flange and the second flange, the time required for manufacturing can be shortened.

[0022] In one or more embodiments, the portion of the spindle that faces the opening surrounded by the first flange, the second flange and the plurality of connecting portions may be a non-cutting portion.

[0023] In the above configuration, the opening of the slit portion can be formed by the non-cut portion, so that cutting is not required when forming the opening.

[0024] In one or more embodiments, the spindle is a spindle for use in a power tool, and includes a flange portion having an axial hole for inserting a sun gear and a slit portion on at least a side for attaching a planetary gear, and a shaft portion extending forward from the flange portion, and the flange portion may be in a formed state by forging.

[0025] In the above-described configuration, since the flange portion is formed by forging, it is possible to reduce the time required to manufacture the spindle.

[0026] In one or more embodiments, the flange portion may have a cut surface on at least a portion of its surface.

[0027] In the above-described configuration, the surface of the flange portion formed by forging can be appropriately cut as necessary, thereby improving the accuracy of the outer shape of the spindle.

[0028] In one or more embodiments, the shaft portion may have a spindle groove in which at least a portion of the ball is disposed.

[0029] With the above configuration, when manufacturing a spindle having a spindle groove in a shaft portion in which at least a portion of the ball is disposed, the time required for manufacturing can be shortened.

[0030] In one or more embodiments, the alloy may be formed using iron containing at least 0.13% and no more than 1.00% carbon and at least 0.90% chromium.

[0031] In the above-described configuration, it is possible to appropriately perform plastic deformation by forging, and it is possible to ensure the strength after deformation.

[0032] In one or more embodiments, the flange portion may have grain flows formed by forging extending radially outward from the center.

[0033] In the above configuration, grain flows are formed by forging in the flange portion from the center toward the outside in the radial direction, so that appropriate strength can be ensured.

[0034] In one or more embodiments, the flange portion may include a first flange connected to the shaft portion, a second flange positioned rearward of the first flange and opposite the first flange, and a connecting portion axially connecting the first flange and the second flange.

[0035] With the above configuration, when manufacturing a spindle having a first flange, a second flange, and a connecting portion, the time required for manufacturing can be shortened.

[0036] In one or more embodiments, a plurality of the connecting portions may be arranged in the circumferential direction, and the planetary gears may be arranged between adjacent connecting portions in the portion sandwiched between the first flange and the second flange.

[0037] With the above configuration, when manufacturing a spindle in which planetary gears are arranged between adjacent connecting portions in the portion sandwiched between the first flange and the second flange, the time required for manufacturing can be shortened.

[0038] In one or more embodiments, the flange portion may have a non-cut portion that faces the opening surrounded by the first flange, the second flange and the multiple connecting portions.

[0039] In the above configuration, the opening of the slit portion can be formed by the non-cut portion, so that cutting is not required when forming the opening.

[0040] In one or more embodiments, a method for manufacturing a spindle for use in an electric tool includes a flange portion having a hole in the axial direction for inserting a sun gear and a slit portion on at least a side for attaching a planetary gear, and a shaft portion extending forward from the flange portion, and may include the steps of forming a slug having a flange corresponding portion and a shaft corresponding portion corresponding to the flange portion and the shaft portion, respectively, placing a mold in which a slit corresponding portion corresponding to the slit portion is formed on the flange corresponding portion of the slug, and forming the slit portion by forging with the mold placed in place, in which the rear end portion of the flange corresponding portion is struck in the axial direction to plastically deform the flange corresponding portion along the slit corresponding portion of the mold.

[0041] In the above configuration, the slit portion is formed by forging, in which a die in which a slit corresponding portion corresponding to the slit portion is formed is placed against the flange corresponding portion of the slug, and the rear end of the flange corresponding portion is struck in the axial direction to plastically deform the flange corresponding portion along the slit corresponding portion of the die. Therefore, the slit portion can be efficiently formed by forging, and the time required for manufacturing the spindle can be shortened.

[0042] In one or more embodiments, the spindle may have a hole in the axial direction in the flange portion for inserting the sun gear, and the method may further include a step of forming the hole by cutting the flange corresponding portion after plastically deforming the flange corresponding portion.

[0043] In the above configuration, the slit portion is formed by forging and then the hole is formed by cutting, thereby reducing the time required to manufacture the spindle compared to when both the slit portion and the hole are formed by cutting.

[0044] In one or more embodiments, the slug may be forged at a material temperature of -20° C. to 40° C., 300° C. to 850° C., or 1000° C. to 1250° C., and the spindle may be forged at a material temperature of -20° C. to 40° C. When forging the slug, the slug may be at any temperature in the range of -20° C. to 1250° C.

[0045] In the above-described configuration, the slug can be properly manufactured, and the properly manufactured slug can be used to properly manufacture a spindle.

[0046] In one or more embodiments, the spindle may be formed by forging and then heat treating to provide a surface hardness of 300 HV or greater.

[0047] In the above configuration, the surface hardness becomes 300HV or more by heat treatment after forming by forging, which makes it possible to ensure the strength of the spindle 8. Note that the heat treatment may be any treatment that changes the properties of the material, such as quenching such as through quenching, carburizing quenching, carbonitriding quenching, and induction quenching, or age hardening.

[0048] Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings, but the present disclosure is not limited to the embodiment. The components of the embodiments described below can be appropriately combined. In addition, some components may not be used.

[0049] In the embodiments, the positional relationship of each part will be described using the terms left, right, front, rear, top, and bottom. These terms indicate a relative position or direction based on the center of the power tool.

[0050] The electric power tool has a motor. In the embodiments, a direction parallel to a rotation axis AX of the motor is referred to as an axial direction, a direction going around the rotation axis AX is referred to as a circumferential direction or a rotation direction, and a radial direction of the rotation axis AX is referred to as a radial direction.

[0051] In the embodiment, the rotation axis AX extends in the front-rear direction. The axial direction and the front-rear direction coincide with each other. One side in the axial direction is the front, and the other side in the axial direction is the rear. In addition, in the radial direction, a position close to or approaching the rotation axis AX is appropriately referred to as the radially inner side, and a position far from or away from the rotation axis AX is appropriately referred to as the radially outer side.

[0052] Fig. 1 is a front perspective view showing the impact tool 1 according to the embodiment. Fig. 2 is a side view showing the upper part of the impact tool 1 according to the embodiment. Fig. 3 is a vertical cross-sectional view showing the upper part of the impact tool 1 according to the embodiment. Fig. 4 is a horizontal cross-sectional view showing the upper part of the impact tool 1 according to the embodiment. Fig. 5 is a right side view showing the impact tool 1 according to the embodiment.

[0053] In the embodiment, an impact tool 1 will be described as an example of a power tool. In the embodiment, the impact tool 1 is an impact driver, which is a type of screw tightening tool. The impact tool 1 includes a housing 2, a rear cover 3, a hammer case 4, a bearing box 24, a hammer case cover 51, a bumper 52, a motor 6, a reduction mechanism 7, a spindle 8, a striking mechanism 9, an anvil 10, a tool holding mechanism 11, a fan 12, a battery mounting section 13, a trigger lever 14, a forward / reverse rotation switching lever 15, an interface panel 16, a hand mode switching button 17, and a light assembly 18.

[0054] The housing 2 is made of synthetic resin. In this embodiment, the housing 2 is made of nylon. The housing 2 includes a left housing 2L and a right housing 2R disposed to the right of the left housing 2L. The left housing 2L and the right housing 2R are fixed together by a plurality of screws 2S. The housing 2 is composed of a pair of half housings.

[0055] The housing 2 has a motor accommodating portion 21, a grip portion 22, and a battery holding portion 23.

[0056] The motor accommodating portion 21 accommodates the motor 6. The motor accommodating portion 21 accommodates at least a portion of the hammer case 4. The motor accommodating portion 21 is cylindrical.

[0057] The grip portion 22 is held by an operator. The grip portion 22 extends downward from the motor housing portion 21. The trigger lever 14 is provided on an upper portion of the grip portion 22.

[0058] The battery holding portion 23 holds the battery pack 25 via the battery attachment portion 13. The battery holding portion 23 is connected to a lower end portion of the grip portion 22. The outer dimensions of the battery holding portion 23 are larger than the outer dimensions of the grip portion 22 in both the front-rear direction and the left-right direction.

[0059] The rear cover 3 is positioned so as to cover the opening at the rear end of the motor accommodating portion 21. The rear cover 3 is positioned behind the motor accommodating portion 21. The rear cover 3 accommodates at least a portion of the fan 12. The fan 12 is positioned inside the rear cover 3. The rear cover 3 holds a rear rotor bearing 37. The rear cover 3 is made of synthetic resin. The rear cover 3 is fixed to the rear end of the motor accommodating portion 21 with two screws 3S.

[0060] The motor accommodating portion 21 has an air intake port 19. The rear cover 3 has an air exhaust port 20. Air in the external space of the housing 2 flows into the internal space of the housing 2 through the air intake port 19. Air in the internal space of the housing 2 flows out to the external space of the housing 2 through the air exhaust port 20.

[0061] The hammer case 4 accommodates at least a portion of the reduction mechanism 7, the spindle 8, the striking mechanism 9, and at least a portion of the anvil 10. The hammer case 4 is made of metal. In the embodiment, the hammer case 4 is made of aluminum. The hammer case 4 is cylindrical. The hammer case 4 is connected to the front part of the motor accommodating section 21. A bearing box 24 is fixed to the rear part of the hammer case 4. The bearing box 24 accommodates at least a portion of the reduction mechanism 7. The bearing box 24 holds the front rotor bearing 38 and the spindle bearing 44. The bearing box 24 is made of metal. The bearing box 24 is fixed to the rear part of the hammer case 4.

[0062] The hammer case 4 is sandwiched between the left housing 2L and the right housing 2R. A rear portion of the hammer case 4 is housed in the motor housing portion 21. The hammer case 4 is connected to a front portion of the motor housing portion 21. A bearing box 24 is fixed to each of the motor housing portion 21 and the hammer case 4.

[0063] The hammer case cover 51 protects the hammer case 4. The hammer case cover 51 suppresses contact between the hammer case 4 and objects around the hammer case 4. The hammer case cover 51 is disposed so as to cover the outer peripheral surface of the large cylinder portion 4A.

[0064] The bumper 52 protects the hammer case 4. The bumper 52 suppresses contact between the hammer case 4 and objects around the hammer case 4. The bumper 52 reduces impact when the hammer case 4 comes into contact with an object. The bumper 52 is disposed around the small cylinder portion 4B.

[0065] The motor 6 is a power source of the impact tool 1. The motor 6 is an inner rotor type brushless motor. The motor 6 has a stator 26 and a rotor 27. The stator 26 is supported by the motor accommodating portion 21. At least a portion of the rotor 27 is disposed inside the stator 26. The rotor 27 rotates relative to the stator 26. The rotor 27 rotates about a rotation axis AX extending in the front-rear direction.

[0066] The stator 26 includes a stator core 28 , a rear insulator 29 , a front insulator 30 , and a coil 31 .

[0067] The stator core 28 includes a plurality of stacked steel plates. The steel plates are made of a metal whose main component is iron. The stator core 28 is cylindrical. The stator core 28 is disposed radially outward of the rotor 27. The stator core 28 has a plurality of teeth that support the coils 31.

[0068] The rear insulator 29 and the front insulator 30 are each an electrical insulating member made of synthetic resin. The rear insulator 29 and the front insulator 30 each electrically insulate the stator core 28 from the coil 31. The rear insulator 29 is fixed to the rear of the stator core 28. The front insulator 30 is fixed to the front of the stator core 28. The rear insulator 29 is arranged so as to cover a portion of the surface of the teeth. The front insulator 30 is arranged so as to cover a portion of the surface of the teeth.

[0069] The coil 31 is attached to the stator core 28 via the rear insulator 29 and the front insulator 30. A plurality of coils 31 are arranged. The coils 31 are arranged around the teeth of the stator core 28 via the rear insulator 29 and the front insulator 30. The coils 31 and the stator core 28 are electrically insulated by the front insulator 30 and the rear insulator 29. The multiple coils 31 are connected via fusing terminals 36.

[0070] The rotor 27 rotates about a rotation axis AX. The rotor 27 includes a rotor core 32, a rotor shaft 33, a rotor magnet 34A, and a sensor magnet 34B.

[0071] The rotor core 32 and the rotor shaft 33 are each made of steel. In this embodiment, the rotor core 32 and the rotor shaft 33 are integral with each other. A rear portion of the rotor shaft 33 protrudes rearward from a rear end surface of the rotor core 32. A front portion of the rotor shaft 33 protrudes forward from a front end surface of the rotor core 32.

[0072] The rotor magnet 34A is fixed to the rotor core 32. In the embodiment, the rotor magnet 34A is disposed around the rotor core 32. The sensor magnet 34B is fixed to the rotor core 32. In the embodiment, the sensor magnet 34B is disposed on the front end surface of the rotor core 32.

[0073] A sensor board 35 is attached to the front insulator 30. The sensor board 35 is fixed to the front insulator 30 with screws 30S. The sensor board 35 has an annular circuit board and a rotation detection element supported by the circuit board. At least a portion of the sensor board 35 faces the front end surface of the sensor magnet 34B. The rotation detection element detects the position of the sensor magnet 34B, thereby detecting the position of the rotor 27 in the rotational direction.

[0074] The rear end of the rotor shaft 33 is rotatably supported by a rear rotor bearing 37. The front end of the rotor shaft 33 is rotatably supported by a front rotor bearing 38. The rear rotor bearing 37 is held by the rear cover 3. The front rotor bearing 38 is held by the bearing box 24.

[0075] The front end of the rotor shaft 33 is disposed in the internal space of the hammer case 4 through an opening provided in the rear annular portion 24 A of the bearing box 24 .

[0076] A pinion gear (sun gear) 41 is formed on the front end of the rotor shaft 33. The pinion gear 41 is connected to at least a part of the reduction mechanism 7. The rotor shaft 33 is connected to the reduction mechanism 7 via the pinion gear 41.

[0077] The reduction mechanism 7 connects the rotor shaft 33 and the spindle 8. A gear of the reduction mechanism 7 is driven by the rotor 27. The reduction mechanism 7 transmits the rotation of the rotor 27 to the spindle 8. The reduction mechanism 7 rotates the spindle 8 at a rotational speed lower than the rotational speed of the rotor shaft 33. The reduction mechanism 7 is disposed forward of the stator 26. The reduction mechanism 7 includes a planetary gear mechanism.

[0078] The reduction mechanism 7 has a plurality of planetary gears 42 arranged around the pinion gear 41, and an internal gear 43 arranged around the plurality of planetary gears 42. The pinion gear 41, the planetary gear 42, and the internal gear 43 are each housed in the hammer case 4. Each of the plurality of planetary gears 42 meshes with the pinion gear 41. The planetary gear 42 is rotatably supported by the spindle 8 via a pin 42P. The spindle 8 is rotated by the planetary gear 42. The internal gear 43 has internal teeth that mesh with the planetary gear 42.

[0079] The internal gear 43 is fixed to the large cylindrical portion 4A of the hammer case 4. The internal gear 43 is always non-rotatable relative to the hammer case 4.

[0080] When the rotor shaft 33 is rotated by the drive of the motor 6, the pinion gear 41 rotates and the planetary gear 42 revolves around the pinion gear 41. The planetary gear 42 revolves while meshing with the internal teeth of the internal gear 43. Due to the revolution of the planetary gear 42, the spindle 8 connected to the planetary gear 42 via the pin 42P rotates at a rotational speed lower than the rotational speed of the rotor shaft 33.

[0081] Fig. 5 is an exploded perspective view showing a main part of the impact tool 1 according to the embodiment. Fig. 6 is a bottom view showing the spindle 8 according to the embodiment. Figs. 7A and 7B are diagrams showing grain flows in a solid portion of the spindle 8 according to the embodiment. Fig. 8 is a side view of the spindle 8 according to the embodiment.

[0082] The spindle 8 is rotated about the rotation axis AX by the motor 6. The spindle 8 is rotated by the rotor 27. The spindle 8 rotates by the rotational force of the rotor 27 transmitted via the reduction mechanism 7. The spindle 8 transmits the rotational force of the motor 6 to the anvil 10 via a ball 48 and a hammer 47. At least a portion of the spindle 8 is disposed forward of the motor 6. The spindle 8 is disposed forward of the stator 26. At least a portion of the spindle 8 is disposed forward of the rotor 27. At least a portion of the spindle 8 is disposed forward of the reduction mechanism 7. At least a portion of the spindle 8 is disposed rearward of the anvil 10.

[0083] The spindle 8 has a spindle shaft portion 8A and a flange portion 8L.

[0084] The spindle shaft portion 8A is rod-shaped and long in the front-rear direction. The central axis of the spindle shaft portion 8A coincides with the rotation axis AX. The spindle shaft portion 8A has a spindle protrusion 8F. The spindle protrusion 8F protrudes forward from the front end portion of the spindle shaft portion 8A.

[0085] The flange portion 8L has a first flange portion 8B, a second flange portion 8C, and a connecting portion 8D. The first flange portion 8B extends radially outward from the rear end of the outer circumferential surface of the spindle shaft portion 8A. The second flange portion 8C is disposed rearward of the first flange portion 8B. The second flange portion 8C is annular. The second flange portion 8C has an insertion hole 8H in the axial direction for inserting the pinion gear 41. The insertion hole 8H is disposed in the center of the second flange portion 8C in the vertical and horizontal directions.

[0086] A slit portion 8I is formed between the first flange portion 8B and the second flange portion 8C. The slit portion 8I is a space for mounting the planetary gear 42. At least a portion of the slit portion 8I is open to the side surface of the flange portion 8L.

[0087] The connecting portion 8D connects a part of the first flange portion 8B and a part of the second flange portion 8C. The connecting portion 8D is arranged on a side surface of the flange portion 8L. In this embodiment, a plurality of the connecting portions 8D are arranged at equal intervals in the circumferential direction. The connecting portion 8D defines a slit portion 8I at the peripheral portion of the first flange portion 8B and the second flange portion 8C. The front end portion of the pin 42P is supported by the first flange portion 8B. The rear end portion of the pin 42P is supported by the second flange portion 8C. The planetary gear 42 is arranged between the first flange portion 8B and the second flange portion 8C. The planetary gear 42 is rotatably supported by the first flange portion 8B and the second flange portion 8C via the pin 42P. The planetary gear 42 is arranged between the adjacent connecting portions 8D in the portion sandwiched between the first flange portion 8B and the second flange portion 8C.

[0088] The spindle bearing 44 (see FIG. 4, etc.) is disposed inside the cylindrical portion 8E of the spindle 8 that protrudes rearward from the rear surface of the second flange portion 8C. The spindle bearing 44 holds the cylindrical portion 8E of the spindle 8. The spindle bearing 44 is held in the bearing box 24.

[0089] In this embodiment, the spindle 8 is in a state where the flange portion 8L is formed by forging. As shown in Figs. 7A and 7B, the spindle 8 has grain flows 8T formed by forging in a cross-sectional view. Fig. 7A shows grain flows when forging is performed by an upsetting method described later, and Fig. 7B shows grain flows when forging is performed by a rearward extrusion method described later. As shown in Figs. 7A and 7B, the grain flows 8T are formed from the center in the radial direction toward the outside in the first flange portion 8B, the second flange portion 8C, the connecting portion 8D, and the cylindrical portion 8E of the flange portion 8L. In the example shown in Fig. 7A, the grain flows 8T are formed along the radial direction in the cylindrical portion 8E. The grain flows 8T formed in the cylindrical portion 8E are formed in a state separated from other portions such as the second flange portion 8C. On the other hand, in the example shown in Fig. 7B, the grain flows 8T are formed in a state where they are connected from the cylindrical portion 8E to the second flange portion 8C. In this manner, the shape of grain flows 8T formed in flange portion 8L differs between when forging is performed by the upsetting method and when forging is performed by the rear ejection method.

[0090] The portion of the spindle 8 facing the opening surrounded by the first flange portion 8B, the second flange portion 8C, and the multiple connecting portions 8D is the non-cut portion 8K. The non-cut portion 8K is a portion of the surface formed by forging that has not been cut. In the spindle 8, the portions other than the non-cut portion 8K have been cut. In this way, the opening of the slit portion 8I can be formed by the non-cut portion 8K, so that cutting is not required when forming the opening.

[0091] The spindle 8 is made of iron containing 0.13% to 1.00% carbon and 0.90% or more chromium. The spindle 8 may be made of iron containing at least carbon, chromium, and molybdenum. This configuration allows for appropriate plastic deformation by forging, and ensures strength after deformation.

[0092] The striking mechanism 9 is driven by the motor 6. The rotational force of the motor 6 is transmitted to the striking mechanism 9 via the reduction mechanism 7 and the spindle 8. The striking mechanism 9 strikes the anvil 10 in the rotational direction based on the rotational force of the spindle 8 rotated by the motor 6. The striking mechanism 9 has a hammer 47, a ball 48, a coil spring 49, and a washer 50. The striking mechanism 9 including the hammer 47, the ball 48, the coil spring 49, and the washer 50 is housed in the large cylinder portion 4A of the hammer case 4.

[0093] The hammer 47 is disposed forward of the reduction mechanism 7. The hammer 47 is disposed around the spindle 8. The hammer 47 is disposed around the spindle shaft portion 8A. The hammer 47 is held by the spindle shaft portion 8A. The ball 48 is disposed between the spindle 8 and the hammer 47.

[0094] The hammer 47 is rotated by the motor 6. The rotational force of the motor 6 is transmitted to the hammer 47 via the reduction mechanism 7 and the spindle 8. The hammer 47 can rotate together with the spindle 8 based on the rotational force of the spindle 8 rotated by the motor 6. The rotation axis of the hammer 47, the rotation axis of the spindle 8, and the rotation axis AX of the motor 6 coincide with each other. The hammer 47 rotates around the rotation axis AX.

[0095] The washer 50 is disposed inside the recess 47E. The washer 50 is supported by the hammer 47 via a plurality of balls 54. The balls 54 are disposed forward of the washer 50. The balls 54 are disposed between the rear surface of the body portion 47A and the front surface of the washer 50.

[0096] The coil spring 49 is disposed around the spindle shaft portion 8A. The rear end of the coil spring 49 is supported by the first flange portion 8B. The front end of the coil spring 49 is disposed inside the recess 47E and supported by a washer 50. The coil spring 49 constantly generates an elastic force that moves the hammer 47 forward.

[0097] The ball 48 is made of a metal such as steel. The ball 48 is disposed between the spindle shaft portion 8A and the body portion 47A. The spindle shaft portion 8A has a spindle groove 8G in which at least a portion of the ball 48 is disposed. The spindle groove 8G is provided on a portion of the outer circumferential surface of the spindle shaft portion 8A. The hammer 47 has a hammer groove 47G in which at least a portion of the ball 48 is disposed. The hammer groove 47G is provided on a portion of the inner circumferential surfaces of the body portion 47A and the inner cylinder portion 47C.

[0098] Two balls 48 are provided. Two spindle grooves 8G are provided on the outer peripheral surface of the spindle shaft portion 8A. Two hammer grooves 47G are provided on the inner peripheral surfaces of the body portion 47A and the inner cylinder portion 47C. One ball 48 is disposed between one spindle groove 8G and one hammer groove 47G. The other ball 48 is disposed between the other spindle groove 8G and the other hammer groove 47G. The ball 48 can roll on the inside of the spindle groove 8G and the inside of the hammer groove 47G. The hammer 47 can move along with the ball 48. The spindle 8 and the hammer 47 can move relative to each other in the axial direction and the rotational direction within a movable range defined by the spindle groove 8G and the hammer groove 47G.

[0099] The anvil 10 is disposed forward of the motor 6. The anvil 10 is an output part of the impact tool 1 that rotates based on the rotational force of the rotor 27. At least a portion of the anvil 10 is disposed forward of the spindle 8. At least a portion of the anvil 10 is disposed forward of the hammer 47. The anvil 10 is struck by the hammer 47 in the rotational direction.

[0100] The anvil 10 has an anvil shaft portion 10A and an anvil protrusion portion 10B. The anvil shaft portion 10A is rod-shaped and long in the front-rear direction. The central axis of the anvil shaft portion 10A coincides with the rotation axis AX. The anvil protrusion portion 10B is provided at the rear end portion of the anvil shaft portion 10A. The anvil protrusion portion 10B protrudes radially outward from the rear end portion of the anvil shaft portion 10A. Two anvil protrusion portions 10B are provided.

[0101] A tool hole 10C is provided in the front end surface of the anvil 10. An anvil recess 10D is provided in the rear end surface of the anvil 10. The tool hole 10C is formed to extend rearward from the front end surface of the anvil shaft portion 10A. A tool tip is inserted into the tool hole 10C. The tool tip is attached to the anvil 10. The anvil recess 10D is provided to be recessed forward from the rear end surface of the anvil 10. A spindle protrusion 8F is disposed in the anvil recess 10D.

[0102] The anvil 10 is rotatably supported by the anvil bearing 46. The rotation axis of the anvil 10, the rotation axis of the hammer 47, the rotation axis of the spindle 8, and the rotation axis AX of the motor 6 are aligned. The anvil 10 rotates around the rotation axis AX. The anvil bearing 46 is disposed around the anvil shaft portion 10A. An O-ring 45 is disposed between the anvil bearing 46 and the anvil shaft portion 10A. The anvil bearing 46 is disposed inside the small cylinder portion 4B of the hammer case 4. The anvil bearing 46 is held by the small cylinder portion 4B of the hammer case 4. The hammer case 4 supports the anvil 10 via the anvil bearing 46. The anvil bearing 46 rotatably supports the front portion of the anvil shaft portion 10A. In the embodiment, two anvil bearings 46 are disposed in the front-rear direction.

[0103] A washer 56 is disposed in front of the anvil protrusion 10B. The washer 56 prevents contact between the front surface of the anvil protrusion 10B and the hammer case 4. A support member 57 is disposed behind the anvil bearing 46. The support member 57 is disposed so as to contact the rear surface of the outer ring of the anvil bearing 46. The support member 57 is ring-shaped. The support member 57 prevents the anvil bearing 46 from slipping rearward from the small cylinder portion 4B. The support member 57 is disposed in a groove provided on the inner surface of the small cylinder portion 4B.

[0104] The hammer protrusion 47D can come into contact with the anvil protrusion 10B. When the motor 6 is driven in a state in which the hammer protrusion 47D and the anvil protrusion 10B are in contact with each other, the anvil 10 rotates together with the hammer 47 and the spindle 8.

[0105] The anvil 10 is struck in the rotational direction by the hammer 47. For example, in a screw tightening operation, when the load acting on the anvil 10 becomes high, a situation may occur in which the anvil 10 cannot be rotated by the load of the coil spring 49 alone. When the anvil 10 cannot be rotated by the load of the coil spring 49 alone, the rotation of the anvil 10 and the hammer 47 stops. The spindle 8 and the hammer 47 can move relative to each other in the axial direction and the circumferential direction via the ball 48. Even if the rotation of the hammer 47 stops, the rotation of the spindle 8 continues by the power generated by the motor 6. When the spindle 8 rotates while the rotation of the hammer 47 is stopped, the ball 48 moves backward while being guided by each of the spindle groove 8G and the hammer groove 47G. When the spindle 8 rotates while the rotation of the hammer 47 is stopped, the outer peripheral surface 8S of the spindle 8 and the inner peripheral surface 47S of the hammer 47 slide against each other. The hammer 47 receives a force from the ball 48 and moves rearward along with the ball 48. That is, the hammer 47 moves rearward as the spindle 8 rotates while the rotation of the anvil 10 is stopped. As the hammer 47 moves rearward, the contact between the hammer protrusion 47D and the anvil protrusion 10B is released.

[0106] As described above, the coil spring 49 constantly generates an elastic force that moves the hammer 47 forward. The hammer 47 that has moved backward moves forward due to the elastic force of the coil spring 49. When the hammer 47 moves forward, it receives a force in the rotational direction from the ball 48. That is, the hammer 47 moves forward while rotating. When the hammer 47 moves forward while rotating, the hammer 47 comes into contact with the anvil protrusion 10B while rotating. As a result, the anvil protrusion 10B is struck in the rotational direction by the hammer protrusion 47D of the hammer 47. Both the power of the motor 6 and the inertial force of the hammer 47 act on the anvil 10. Therefore, the anvil 10 can rotate around the rotation axis AX with high torque.

[0107] The tool holding mechanism 11 is disposed around the front part of the anvil 10. The tool holding mechanism 11 holds a tool bit inserted into a tool hole 10C of the anvil 10. The tool holding mechanism 11 is capable of attaching and detaching the tool bit.

[0108] The fan 12 is disposed behind the stator 26 of the motor 6. The fan 12 generates an airflow for cooling the motor 6. The fan 12 is fixed to at least a part of the rotor 27. The fan 12 is fixed to the rear of the rotor shaft 33 via a bush 12A. The fan 12 is disposed between the rear rotor bearing 37 and the stator 26. The fan 12 rotates with the rotation of the rotor 27. The rotor shaft 33 rotates, and the fan 12 rotates together with the rotor shaft 33. As the fan 12 rotates, air in the external space of the housing 2 flows into the internal space of the housing 2 through the intake port 19. The air that has flowed into the internal space of the housing 2 circulates through the internal space of the housing 2, thereby cooling the motor 6. As the fan 12 rotates, the air that has circulated through the internal space of the housing 2 flows out through the exhaust port 20 into the external space of the housing 2.

[0109] The battery mounting section 13 is disposed at the lower part of the battery holding section 23. The battery mounting section 13 is connected to the battery pack 25. The battery pack 25 is mounted to the battery mounting section 13. The battery pack 25 is detachable from the battery mounting section 13. The battery pack 25 is mounted to the battery mounting section 13 by being inserted into the battery mounting section 13 from the front of the battery holding section 23. The battery pack 25 is removed from the battery mounting section 13 by being removed forward from the battery mounting section 13. The battery pack 25 includes a secondary battery. In the embodiment, the battery pack 25 includes a rechargeable lithium ion battery. By being mounted to the battery mounting section 13, the battery pack 25 can supply power to the impact tool 1. The motor 6 is driven based on the power supplied from the battery pack 25.

[0110] The trigger lever 14 is provided on the grip portion 22. The trigger lever 14 is operated by an operator to start the motor 6. By operating the trigger lever 14, the motor 6 is switched between being driven and being stopped.

[0111] The forward / reverse switching lever 15 is provided on the upper part of the grip portion 22. The forward / reverse switching lever 15 is operated by an operator. By operating the forward / reverse switching lever 15, the rotation direction of the motor 6 is switched from one of the forward direction and the reverse direction to the other. By switching the rotation direction of the motor 6, the rotation direction of the spindle 8 is switched.

[0112] The interface panel 16 is provided on the battery holding portion 23. The interface panel 16 is provided on the upper surface of the battery holding portion 23, further forward than the grip portion 22. The interface panel 16 has an operation button 16A. There may be one or more operation buttons 16A. In the embodiment, a plurality of operation buttons 16A are provided. The operation mode of the motor 6 is switched by an operator operating the operation button 16A.

[0113] The hand mode switching button 17 is provided on the upper part of the trigger lever 14. The hand mode switching button 17 is operated by an operator. By operating the hand mode switching button 17, the control mode of the motor 6 is switched.

[0114] The light assembly 18 emits illumination light. The light assembly 18 illuminates the anvil 10 and the periphery of the anvil 10 with illumination light. The light assembly 18 illuminates the front of the anvil 10 with illumination light. The light assembly 18 also illuminates the tool attachment attached to the anvil 10 and the periphery of the tool with illumination light. In the embodiment, the light assemblies 18 are disposed on the left and right sides of the large cylinder portion 4A of the hammer case 4.

[0115] The spindle 8 has an internal space 60. An opening is provided in the rear end surface of the spindle 8. The internal space 60 is formed inside the spindle 8 so as to extend forward from the opening provided in the rear end surface of the spindle 8. Lubricating oil is stored in the internal space 60. The lubricating oil includes grease. The front end of the pinion gear 41 is inserted into the rear end of the internal space 60 through the opening in the rear end surface of the spindle 8.

[0116] Fig. 9 is a flowchart showing an example of a method for manufacturing the spindle 8 according to the embodiment. As shown in Fig. 9, the method for manufacturing the spindle 8 includes a slug preparation step S10, a die arrangement step S20, a forging step S30, a cutting step S40, and a heat treatment step S50.

[0117] In the slug preparation step S10, a slug 70 that serves as a prototype of the spindle 8 is formed. The slug 70 can be formed by a method such as forging. In this case, the slug 70 can be formed at a temperature of -20°C or more and 40°C or less (cold forging), 300°C or more and 850°C or less (warm forging), or 1000°C or more and 1250°C or less (hot forging). Note that in the slug preparation step S10, the temperature of the slug 70 may be any temperature within the range of -20°C or more and 1250°C or less.

[0118] 10 is a diagram showing an example of a slug 70 according to an embodiment. The slug 70 has a shaft corresponding portion 71 and a flange corresponding portion 72. The shaft corresponding portion 71 is a portion that corresponds to the spindle shaft portion 8A of the spindle 8.

[0119] The flange corresponding portion 72 is a portion corresponding to the flange portion 8L of the spindle 8. The flange corresponding portion 72 has a first flange corresponding portion 72B corresponding to the first flange portion 8B of the spindle 8, and a connection corresponding portion 72D corresponding to the connection portion 8D of the spindle 8. The first flange corresponding portion 72B is disk-shaped. The connection corresponding portion 72D has a shape in which a plate-shaped portion extends from the center in the axial direction in three radial directions. The multiple connection corresponding portions 72D are arranged so that the angles formed with adjacent connection corresponding portions 72D are equal (for example, 120°). Note that the angles formed with adjacent connection corresponding portions 72D by the multiple connection corresponding portions 72D do not have to be equal.

[0120] In the die arrangement step S20, a forging die 80 is arranged with respect to the slug 70. FIG. 11 is a diagram showing an example of the forging die 80 according to the embodiment. FIG. 12 is a diagram showing an example of the die arrangement step S20 according to the embodiment. As shown in FIG. 11, the forging die 80 has a slug support portion 81 and a slit corresponding portion 82. The slug support portion 81 supports the slug 70. The slag support portion 81 has a storage portion 83 and a claw portion 84.

[0121] The accommodating portion 83 accommodates the shaft corresponding portion 71 of the slug 70 and the first flange corresponding portion 72B of the flange corresponding portion 72. The claw portions 84 support the radial outer peripheral side surface of the connection corresponding portion 72D of the slug 70 when it is accommodated in the accommodating portion 83. Three claw portions 84 are arranged at equal pitch in the circumferential direction. When the slug 70 is accommodated in the accommodating portion 83, the outer ends of the three connection corresponding portions 72D of the slug 70 are arranged to face the claw portions 84. The claw portions 84 position the slit corresponding portions 82.

[0122] The slit corresponding portion 82 is a portion corresponding to the slit portion 8I of the spindle 8. The slit corresponding portion 82 is composed of, for example, a plurality of fan-shaped plate-like members. The inner peripheral portion of the slit corresponding portion 82 has a shape corresponding to the connection corresponding portion 72D of the slug 70. As shown in FIG. 12, the slit corresponding portion 82 is disposed between the claw portions 84 adjacent to each other in the circumferential direction when the slug 70 is accommodated in the accommodation portion 83. In other words, the slit corresponding portion 82 is disposed so as to fill the gap between the connection corresponding portions 72D adjacent to each other in the circumferential direction of the slug 70.

[0123] In the forging step S30, with the forging die 80 positioned as described above, the rear end 72E of the flange corresponding portion 72 is struck in the axial direction to plastically deform the flange corresponding portion 72 along the slit corresponding portion 82 of the forging die 80. The forging step S30 can be performed with the temperature of the slag 70 at, for example, about 25° (cold forging).

[0124] 13A and 13B are diagrams showing an example of the forging process S30 according to the embodiment. As shown in FIG. 13A, in the forging process S30, the rear end 72E is struck using a press hammer having a diameter larger than that of the flange corresponding portion 72 (upsetting method). In this case, as shown in FIG. 13B, the rear end 72E of the flange corresponding portion 72 is crushed in its entirety, and the rear end 72E can be plastically deformed so as to spread radially along the slit corresponding portion 82. This crushed and spread portion becomes the second flange corresponding portion 72C corresponding to the second flange portion 8C and the cylindrical portion 8E of the spindle 8. In addition, a slit portion 8I is formed in the portion where the slit corresponding portion 82 is disposed. After the flange corresponding portion 72 is plastically deformed, the slit corresponding portion 82 is removed, and the slug 70 is taken out of the storage portion 83.

[0125] In the cutting step S40, the flange corresponding portion 72 is cut from the slug 70 in which the flange corresponding portion 72 has been plastically deformed. FIG. 14A and FIG. 14B are diagrams showing an example of the cutting step S40 according to the embodiment. As shown in FIG. 14A and FIG. 14B, in the cutting step S40, for example, the radially inner portion of the connection corresponding portion 72D is cut and the radially outer portion is left, thereby forming the connection portion 8D of the spindle 8 and connecting the slit portion 8I at the radially inner portion. In addition, the second flange corresponding portion 72C is cut to form the second flange portion 8C, the cylindrical portion 8E, and the insertion hole 8H. The shaft corresponding portion 71 and the first flange corresponding portion 72B can be the spindle shaft portion 8A and the first flange portion 8B as they are. Note that, if necessary, the outer periphery of the first flange corresponding portion 72B and the connection corresponding portion 72D may be cut to adjust the outer shape of the first flange portion 8B and the connection portion 8D. In the cutting step S40, a cutting surface 8J is formed on the surface of the cut portion. The portion of the spindle 8 that is not cut in the cutting step S40 and faces the opening 8P surrounded by the first and second flanges 8B and 8C and the multiple connecting portions 8D is the non-cut portion 8K. Figs. 14C and 14D are schematic diagrams showing another example of the grain flow in the solid portion of the spindle 8 according to the embodiment. Figs. 14C and 14D show an example of the grain flow of the slag 70 before and after cutting within a dashed line frame. As shown in Figs. 14C and 14D, when forging is performed by the upsetting method, the grain flow is formed so as to spread radially forward from the rear end of the rear end 72E. By performing cutting from a state in which the grain flow is formed in this way, the grain flow of the tubular portion 8E is separated from other portions.

[0126] 15A and 15B are diagrams showing another example of the forging step S30 according to the embodiment. As shown in FIG. 15A and FIG. 15B, in the forging step S30, the radial outside of the flange corresponding portion 72 may be surrounded by another die 86, and a press hammer 85 having a diameter smaller than that of the flange corresponding portion 72 may be used to strike the center of the rear end portion 72E (rearward extrusion method). In this case, the rear end portion 72E can be plastically deformed so that the center of the rear end portion 72E of the flange corresponding portion 72 is crushed so as to be recessed relative to the peripheral portion, and the peripheral portion rises rearward along the inner circumference of the die (rising portion 72F). By performing forging in the rearward extrusion mode, the radial outer periphery of the portion that becomes the second flange corresponding portion 72C can be shaped to conform to the die. The rear end portion 72E on which the rising portion 72F is formed has a shape that conforms to the cylindrical portion 8E.

[0127] 16A and 16B are diagrams showing another example of the cutting step S40 according to the embodiment. When the forging step S30 is performed by the backward extrusion method, in the cutting step S40, as shown in FIG. 16A and FIG. 16B, the flange corresponding portion 72 is cut. In the cutting step S40, for example, the raised portion 72F is cut to form the cylindrical portion 8E. In addition, for example, the radial inner portion of the connection corresponding portion 72D is cut and the radial outer portion is left, thereby forming the connection portion 8D of the spindle 8 and connecting the slit portion 8I at the radial inner portion. In addition, the second flange corresponding portion 72C is cut from the state in which the raised portion 72F is cut, thereby forming the second flange portion 8C and the insertion hole 8H. The shaft corresponding portion 71 and the first flange corresponding portion 72B can be the spindle shaft portion 8A and the first flange portion 8B as they are. If necessary, the outer periphery of the first flange corresponding portion 72B and the connection corresponding portion 72D may be cut to adjust the outer shape of the first flange portion 8B and the connection portion 8D. The cutting step S40 forms a cutting surface 8J on the surface of the cut portion. The portion that is not cut in the cutting step S40 and faces the opening 8P surrounded by the first flange portion 8B, the second flange portion 8C, and the multiple connection portions 8D becomes a non-cut portion 8K. Figs. 16C and 16D are diagrams showing another example of grain flows in the solid portion of the spindle 8 according to the embodiment. Figs. 16C and 16D show an example of grain flows of the slag 70 before and after cutting within a dot-dash line frame. As shown in Figs. 16C and 16D, when forging is performed by the rear extrusion method, grain flows are formed so as to curve from the center of the rear end portion 72E to the rear end of the rising portion 72F. By cutting the raised portion 72F to form the tubular portion 8E after the grain flow has been formed in this manner, the grain flow is connected from the radial center of the rear end of the second flange portion 8C to the tubular portion 8E.

[0128] In the heat treatment step S50, the cut slug 70 is heat-treated. In the heat treatment step S50, heat treatment is performed so that the surface hardness of the cut slug 70 is 300 HV or more. In the heat treatment step S50, any treatment may be used as long as it is a treatment that heats the slug 70 to change the properties of the material, such as quenching such as through quenching, carburizing quenching, carbonitriding quenching, and induction quenching, or age hardening.

[0129] Next, the operation of the impact tool 1 will be described. For example, when performing a screw tightening operation on a work object, a tip tool (driver bit) used for the screw tightening operation is inserted into the tool hole 10C of the anvil 10. The tip tool inserted into the tool hole 10C is held by the tool holding mechanism 11. After the tip tool is attached to the anvil 10, the operator holds the grip portion 22 with, for example, the right hand and pulls the trigger lever 14 with the index finger of the right hand. When the trigger lever 14 is pulled, power is supplied from the battery pack 25 to the motor 6, the motor 6 is started, and at the same time, the light assembly 18 is turned on. When the motor 6 is started, the rotor shaft 33 of the rotor 27 rotates. When the rotor shaft 33 rotates, the rotational force of the rotor shaft 33 is transmitted to the planetary gear 42 via the pinion gear 41. The planetary gear 42 revolves around the pinion gear 41 while rotating on its own axis while meshing with the internal teeth of the internal gear 43. The planetary gear 42 is rotatably supported by the spindle 8 via a pin 42P. The revolution of the planetary gear 42 causes the spindle 8 to rotate at a rotational speed lower than the rotational speed of the rotor shaft 33.

[0130] When the spindle 8 rotates while the hammer 47 and the anvil protrusion 10B are in contact with each other, the anvil 10 rotates together with the hammer 47 and the spindle 8. As the anvil 10 rotates, the screw tightening operation progresses.

[0131] When a load equal to or greater than a predetermined value acts on the anvil 10 as the screw tightening operation progresses, the rotation of the anvil 10 and the hammer 47 stops. When the spindle 8 rotates while the hammer 47 is stopped rotating, the hammer 47 moves rearward. As the hammer 47 moves rearward, the contact between the hammer protrusion 47D and the anvil protrusion 10B is released. The hammer 47 that has moved rearward moves forward while rotating due to the elastic force of the coil spring 49. As the hammer 47 moves forward while rotating, the anvil 10 is struck in the rotational direction by the hammer 47. This causes the anvil 10 to rotate about the rotation axis AX with high torque. Therefore, the screw is tightened to the work object with high torque.

[0132] As described above, in this embodiment, the impact tool 1 includes a motor 6, a pinion gear 41 rotated by the motor 6, at least three planetary gears 42 meshing with the pinion gear 41, an internal gear 43 meshing with the planetary gear 42, a flange portion 8L having an insertion hole 8H in the axial direction for inserting the pinion gear 41 and having a slit portion 8I on at least a side surface for attaching the planetary gear 42, a spindle shaft portion 8A extending axially forward from the flange portion 8L, and the flange portion 8L is in a state formed by forging, a hammer 47 held by the spindle 8, an anvil 10 struck in the rotational direction by the hammer 47, a hammer case 4 that houses the hammer 47 and rotatably holds the anvil 10, a tool holder formed on the anvil 10, and a coil spring 49 that biases the hammer 47 toward the anvil 10.

[0133] In the above configuration, by using the spindle 8 in which the flange portion 8L is formed by forging, it is possible to shorten the time required to manufacture the impact tool 1.

[0134] In this embodiment, the flange portion 8L may have a cutting surface 8J on at least a portion of its surface.

[0135] In the above-described configuration, the accuracy of the outer shape of the spindle 8 can be improved by appropriately cutting the surface of the flange portion 8L in the state formed by forging, as necessary.

[0136] In this embodiment, the spindle 8 may further include a ball 48 disposed between the spindle 8 and the hammer 47, and the spindle 8 may have a spindle groove 8G in the spindle shaft portion 8A in which at least a portion of the ball 48 is disposed.

[0137] With the above-described configuration, when manufacturing a spindle 8 having a spindle groove 8G in a spindle shaft portion 8A in which at least a portion of the ball 48 is disposed, the time required for manufacturing can be shortened.

[0138] In this embodiment, the spindle 8 may be formed using iron containing 0.13% or more and 1.00% or less of carbon and 0.90% or more of chromium.

[0139] In the above-described configuration, it is possible to appropriately perform plastic deformation by forging, and it is possible to ensure the strength after deformation.

[0140] In the present embodiment, the spindle 8 may have grain flows 8T formed by forging in the flange portion 8L from the center toward the outside in the radial direction.

[0141] In the above configuration, grain flows 8T by forging are formed in flange portion 8L of spindle 8 from the center toward the outside in the radial direction, so that appropriate strength can be ensured.

[0142] In this embodiment, the spindle 8 may have a first flange portion 8B connected to the spindle shaft portion 8A, a second flange portion 8C arranged rearward of the first flange portion 8B opposite the first flange portion 8B, and a connecting portion 8D axially connecting the first flange portion 8B and the second flange portion 8C.

[0143] With the above configuration, when manufacturing the spindle 8 having the first flange portion 8B, the second flange portion 8C, and the connecting portion 8D, the time required for manufacturing can be shortened.

[0144] In this embodiment, a plurality of connecting portions 8D may be arranged in the circumferential direction, and the planetary gears 42 may be arranged between adjacent connecting portions 8D in the portion sandwiched between the first flange portion 8B and the second flange portion 8C.

[0145] In the above configuration, when manufacturing a spindle 8 in which planetary gears 42 are arranged between adjacent connecting portions 8D in the portion sandwiched between the first flange portion 8B and the second flange portion 8C, the time required for manufacturing can be shortened.

[0146] In this embodiment, the spindle 8 may have a non-cutting portion 8K that faces an opening surrounded by the first flange portion 8B, the second flange portion 8C, and the multiple connecting portions 8D.

[0147] In the above configuration, the opening of the slit portion 8I can be formed by the non-cut portion 8K, so that no cutting process is required when forming the opening.

[0148] In this embodiment, the spindle 8 is a spindle 8 used in an electric power tool, and includes a flange portion 8L having an insertion hole 8H in the axial direction for inserting the pinion gear 41 and a slit portion 8I on at least a side surface for attaching the planetary gear 42, and a spindle shaft portion 8A extending forward from the flange portion 8L, and the flange portion 8L may be in a formed state by forging.

[0149] In the above configuration, since the flange portion 8L is in a state of being formed by forging, it is possible to shorten the time required to manufacture the spindle 8.

[0150] In this embodiment, the flange portion 8L may have a cut surface on at least a portion of its surface.

[0151] In the above-described configuration, the accuracy of the outer shape of the spindle 8 can be improved by appropriately cutting the surface of the flange portion 8L in the state formed by forging, as necessary.

[0152] In this embodiment, the spindle shaft portion 8A may have a spindle groove 8G in which at least a portion of the ball 48 is disposed.

[0153] With the above-described configuration, when manufacturing a spindle 8 having a spindle groove 8G in a spindle shaft portion 8A in which at least a portion of the ball 48 is disposed, the time required for manufacturing can be shortened.

[0154] In this embodiment, the insulating layer 11 may be formed using iron containing 0.13% or more and 1.00% or less of carbon and 0.90% or more of chromium.

[0155] In the above-described configuration, it is possible to appropriately perform plastic deformation by forging, and it is possible to ensure the strength after deformation.

[0156] In this embodiment, the flange portion 8L may have grain flows 8T formed by forging from the center toward the outside in the radial direction.

[0157] In the above configuration, grain flows 8T by forging are formed from the center toward the outside in the radial direction in flange portion 8L, so that appropriate strength can be ensured.

[0158] In this embodiment, the flange portion 8L may have a first flange portion 8B connected to the spindle shaft portion 8A, a second flange portion 8C arranged rearward of the first flange portion 8B opposite the first flange portion 8B, and a connecting portion 8D axially connecting the first flange portion 8B and the second flange portion 8C.

[0159] With the above configuration, when manufacturing the spindle 8 having the first flange portion 8B, the second flange portion 8C, and the connecting portion 8D, the time required for manufacturing can be shortened.

[0160] In this embodiment, a plurality of connecting portions 8D may be arranged in the circumferential direction, and the planetary gears 42 may be arranged between adjacent connecting portions 8D in the portion sandwiched between the first flange portion 8B and the second flange portion 8C.

[0161] In the above configuration, when manufacturing a spindle 8 in which planetary gears 42 are respectively arranged between adjacent connecting portions 8D in the portion sandwiched between the first flange portion 8B and the second flange portion 8C, the time required for manufacturing can be shortened.

[0162] In this embodiment, the flange portion 8L may have a non-cut portion 8K that faces the opening surrounded by the first flange portion 8B, the second flange portion 8C, and the multiple connecting portions 8D.

[0163] In the above configuration, the opening of the slit portion 8I can be formed by the non-cut portion 8K, so that no cutting process is required when forming the opening.

[0164] In this embodiment, the manufacturing method of the spindle 8 is a method for manufacturing a spindle 8 for use in an electric tool, which includes a flange portion 8L having an insertion hole 8H in the axial direction for inserting a pinion gear 41 and a slit portion 8I on at least a side surface for attaching a planetary gear 42, and a spindle shaft portion 8A extending forward from the flange portion 8L, and may include a step of forming a slug 70 having a flange corresponding portion 72 and a shaft corresponding portion 71 corresponding to the flange portion 8L and the spindle shaft portion 8A, respectively; a step of placing a forging die 80 in which a slit corresponding portion 82 corresponding to the slit portion 8I is formed on the flange corresponding portion 72 of the slug 70; and a step of forming the slit portion 8I by forging in which the rear end portion 72E of the flange corresponding portion 72 is struck in the axial direction with the forging die 80 in place to plastically deform the flange corresponding portion 72 along the slit corresponding portion 82 of the forging die 80.

[0165] In the above configuration, the forging die 80, in which the slit corresponding portion 82 corresponding to the slit portion 8I is formed, is placed on the flange corresponding portion 72 of the slug 70, and the rear end portion 72E of the flange corresponding portion 72 is struck in the axial direction to plastically deform the flange corresponding portion 72 along the slit corresponding portion 82 of the forging die 80, thereby forming the slit portion 8I by forging. Therefore, the slit portion 8I can be efficiently formed by forging, and the time required for manufacturing the spindle 8 can be shortened.

[0166] In this embodiment, the spindle 8 has an insertion hole 8H in the axial direction in the flange portion 8L for inserting the pinion gear 41, and may further include a process of forming the insertion hole 8H by cutting the flange corresponding portion 72 after plastically deforming the flange corresponding portion 72.

[0167] In the above configuration, the slit portion 8I is formed by forging, and then the insertion hole 8H is formed by cutting, so that the time required to manufacture the spindle 8 can be shortened compared to the case where both the slit portion 8I and the insertion hole 8H are formed by cutting.

[0168] In this embodiment, the slug 70 is formed by forging when the temperature of the material is in the range of -20°C to 40°C, 300°C to 850°C, or 1000°C to 1250°C, and the spindle 8 may be formed by forging when the temperature of the formed slug 70 is in the range of -20°C to 40°C.

[0169] In the above-described configuration, the slug 70 can be properly manufactured, and the spindle 8 can be properly manufactured using the properly manufactured slug 70.

[0170] In this embodiment, the spindle 8 may be formed by forging and then heat-treated so that the surface hardness becomes 300 HV or more.

[0171] In the above-described configuration, the surface hardness becomes 300 HV or more by heat treatment after forming by forging, so that the strength of the spindle 8 can be ensured.

[0172] In the above-described embodiment, the power source of the impact tool 1 does not have to be the battery pack 25, and may be a commercial power source (AC power source).

[0173] In the above embodiment, the power tool is the impact tool 1, and the impact tool 1 is an impact driver. The impact tool 1 may be an impact wrench. The power tool may be a driver drill, a polisher, a pin cutter, or a hammer drill. [Explanation of symbols]

[0174] S10...Slag preparation process, S20...Die placement process, S30...Forging process, S40...Cutting process, AX...Rotating shaft, 1...Impact tool, 2...Housing, 2L...Left housing, 2R...Right housing, 2S, 3S, 30S...Screw, 3...Rear cover, 4...Hammer case, 4A...Large cylinder section, 4B...Small cylinder section, 6...Motor, 7...Reduction mechanism, 8...Spindle, 8A...Spindle shaft section, 8B...First flange section, 8C...Second flange section, 8D...Connecting section, 8E...Cylindrical section, 8F...Spindle protrusion section, 8G...Spindle groove, 8H...Insertion hole, 8I...Slit section, 8J...Cutting surface, 8K...Non-cutting section Cutting portion, 8L... flange portion, 8S... outer peripheral surface, 8T... grain flow line, 9... striking mechanism, 10... anvil, 10A... anvil shaft portion, 10B... anvil protrusion portion, 10C... tool hole, 10D... anvil recess portion, 11... tool holding mechanism, 12... fan, 12A... bushing, 13... battery mounting portion, 14... trigger lever, 15... forward / reverse switching lever, 16... interface panel, 16A... operation button, 17... hand mode switching button, 18... light assembly, 19... intake port, 20... exhaust port, 21... motor housing portion, 22... grip portion, 23... battery holding portion, 24... bearing box 24A...rear annular portion, 25...battery pack, 26...stator, 27...rotor, 28...stator core, 29...rear insulator, 30...front insulator, 31...coil, 32...rotor core, 33...rotor shaft, 34A...rotor magnet, 34B...sensor magnet, 35...sensor board, 36...fusing terminal, 37...rear rotor bearing, 38...front rotor bearing, 41...pinion gear, 42...planetary gear, 42P...pin, 43...internal gear, 44...spindle bearing, 45...O-ring, 46...anvil bearing, 47...hand hammer, 47A...body portion, 47C...inner cylinder portion, 47D...hammer protrusion portion, 47E...recess portion, 47G...hammer groove, 47S...inner peripheral surface, 48, 54...ball, 49...coil spring, 50, 56...washer, 51...hammer case cover, 52...bumper, 57...support member, 60...internal space, 70...slug, 71...shaft corresponding portion, 72...flange corresponding portion, 72B...first flange corresponding portion, 72C...second flange corresponding portion, 72D...connection corresponding portion, 72E...rear end portion, 80...forging die, 81...slug support portion, 82...slit corresponding portion, 83...accommodating portion, 84...jaw portion, 85...press hammer

Claims

1. Motor and A sun gear rotated by the motor; at least three planetary gears meshing with the sun gear; an internal gear that meshes with the planetary gear; a spindle including a flange portion having a hole in the axial direction for inserting the sun gear and having a slit portion on at least a side surface for attaching the planetary gear, and a shaft portion extending forward in the axial direction from the flange portion, the flange portion being formed by forging; a hammer held by the spindle; an anvil that is struck in a rotational direction by the hammer; a hammer case that houses the hammer and rotatably holds the anvil; a tool holder formed on the anvil; a coil spring that biases the hammer toward the anvil; An impact tool equipped with

2. The flange portion has a cutting surface on at least a part of its surface.

2. The impact tool according to claim 1.

3. a ball disposed between the spindle and the hammer; The spindle has a spindle groove in the shaft portion in which at least a portion of the ball is disposed.

2. The impact tool according to claim 1.

4. The spindle is formed using iron containing 0.13% to 1.00% carbon and 0.90% or more chromium.

2. The impact tool according to claim 1.

5. The spindle has a forging flow formed from the center toward the outside in the radial direction in the flange portion.

2. The impact tool according to claim 1.

6. The spindle is A first flange connected to the shaft portion; a second flange disposed rearward of the first flange and facing the first flange; a connecting portion that connects the first flange and the second flange in the axial direction; have 2. The impact tool according to claim 1.

7. The connecting portion is arranged in a circumferential direction. The planetary gears are disposed between the adjacent coupling portions in the portions sandwiched between the first flange and the second flange.

7. An impact tool according to claim 6.

8. The spindle has a non-cutting portion that faces an opening surrounded by the first flange, the second flange and the plurality of connecting portions. An impact tool according to claim 6 or 7.

9. A spindle for use in a power tool, a flange portion having a hole in the axial direction for inserting a sun gear and having a slit portion on at least a side surface for attaching a planetary gear; a shaft portion extending forward from the flange portion; Equipped with The flange portion is formed by forging. Spindle.

10. The flange portion has a cutting surface on at least a part of its surface.

10. The spindle of claim 9.

11. The shaft portion has a spindle groove in which at least a portion of the ball is disposed.

10. The spindle of claim 9.

12. Formed using iron containing 0.13% to 1.00% carbon and 0.90% or more chromium.

10. The spindle of claim 9.

13. The flange portion has a grain flow formed by forging from the center toward the outside in the radial direction.

10. The spindle of claim 9.

14. The flange portion is A first flange connected to the shaft portion; a second flange disposed rearward of the first flange and facing the first flange; a connecting portion that connects the first flange and the second flange in the axial direction; have 10. The spindle of claim 9.

15. The connecting portion is arranged in a circumferential direction. The planetary gears are disposed between the adjacent coupling portions in the portions sandwiched between the first flange and the second flange.

15. The spindle of claim 14.

16. The flange portion has a non-cut portion facing an opening surrounded by the first flange, the second flange and the plurality of connecting portions. A spindle according to claim 14 or claim 15.

17. A method for manufacturing a spindle for use in an electric power tool, the spindle comprising: a flange portion having an axial hole for inserting a sun gear and having at least a slit portion on a side surface for attaching a planetary gear; and a shaft portion extending forward from the flange portion, the method comprising the steps of: forming a slug having a flange corresponding portion and a shaft corresponding portion corresponding to the flange portion and the shaft portion, respectively; A step of placing a mold having a slit corresponding portion formed therein corresponding to the slit portion on the flange corresponding portion of the slug; a step of forming the slit portion by forging in which a rear end portion of the flange corresponding portion is struck in an axial direction with the die disposed, so that the flange corresponding portion is plastically deformed along the slit corresponding portion of the die; A method for manufacturing a spindle comprising the steps of:

18. The spindle has a hole in the axial direction, into which a sun gear is inserted, and The method further includes a step of forming the hole by cutting the flange corresponding portion after plastically deforming the flange corresponding portion. A method for manufacturing a spindle according to claim 17.

19. The slag is formed by forging in a state where the temperature of the material is −20° C. or more and 40° C. or less, 300° C. or more and 850° C. or less, or 1000° C. or more and 1250° C. or less, The spindle is formed by forging at a temperature of the formed slug between -20°C and 40°C. A method for manufacturing a spindle according to claim 17.

20. The spindle is formed by forging and then heat-treated so that the surface hardness is 300 HV or more. A method for manufacturing a spindle according to claim 17.

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