Impact tool, spindle, and method for manufacturing spindle

Abstract

The invention provides an impact tool, a main shaft, and a main shaft manufacturing method capable of shortening the time required for manufacturing. The impact tool includes: a motor; a sun gear rotated by the motor; at least three planetary gears engaged with the sun gear; an internal gear engaged with the planetary gear; a main shaft including a flange portion having a hole into which the sun gear is inserted in the axial direction and having a slit portion into which the planetary gear is attached at least on a side surface, 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 main shaft; an anvil hit in the rotational direction by the hammer; a hammer housing that accommodates the hammer and rotatably holds the anvil; a tip tool holding part formed on the anvil; and a coil spring that urges the hammer toward the anvil side.

Description

Technical Field

[0001] The technology disclosed in this specification relates to an impact tool, a spindle, and a method for manufacturing the spindle. Background Art

[0002] In the technical field related to impact tools, an impact tool having a main shaft as disclosed in Patent Document 1 is known.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-037561 Summary of the invention

[0006] Regarding impact tools, it is sought to shorten the time required for manufacturing the spindle.

[0007] The present specification discloses an impact tool. The impact tool comprises: a motor; a sun gear which is rotated by the motor; at least three planetary gears which mesh with the sun gear; an internal gear which meshes with the planetary gear; a main shaft which includes a flange portion and a shaft portion which extends axially forward from the flange portion, wherein the flange portion has a hole for inserting the sun gear in the axial direction and has a slit portion for mounting the planetary gear on at least the side surface, and the flange portion is formed by forging; a hammer which is held on the main shaft; an anvil which is struck in a rotational direction by the hammer; a hammer housing which accommodates the hammer and holds the anvil rotatably; a front end tool holding portion which is formed on the anvil; and a coil spring which urges the hammer toward the anvil side.

[0008] Effects of the Invention

[0009] According to the technology disclosed in this specification, it is possible to provide an impact tool, a spindle, and a method for manufacturing the spindle, which can shorten the time required for manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 The FIG. 1 is a perspective view showing the impact tool according to the embodiment when viewed from the front.

[0011] Figure 2 It is a side view showing an upper portion of the impact tool according to the embodiment.

[0012] Figure 3 It is a longitudinal sectional view showing the upper portion of the impact tool according to the embodiment.

[0013] Figure 4 It is a transverse cross-sectional view showing an upper portion of the impact tool according to the embodiment.

[0014] Figure 5 It is an exploded perspective view showing the main parts of the impact tool according to the embodiment.

[0015] Figure 6 It is a bottom view showing the main shaft according to the embodiment.

[0016] Fig. 7A It is a diagram schematically showing an example of forging flow lines of a solid portion of a main shaft according to an embodiment.

[0017] Figure 7B It is a diagram schematically showing an example of forging flow lines of a solid portion of a main shaft according to an embodiment.

[0018] Figure 8 This is a diagram showing a main shaft according to an embodiment as viewed from the side.

[0019] Fig. 9 This is a flowchart showing an example of a method for manufacturing a main shaft according to the embodiment.

[0020] Fig.10 It is a diagram showing an example of a core according to an embodiment.

[0021] Fig.11 It is a diagram showing an example of a forging die according to the embodiment.

[0022] Fig.12 It is a diagram showing an example of a mold arrangement process according to the embodiment.

[0023] Fig.13A It is a diagram showing an example of a forging process according to the embodiment.

[0024] Fig. 13B It is a diagram showing an example of a forging process according to the embodiment.

[0025] Fig.14A It is a diagram showing an example of a cutting process according to the embodiment.

[0026] Fig. 14B It is a diagram showing an example of a cutting process according to the embodiment.

[0027] Fig. 14C It is a diagram schematically showing an example of forging flow lines of a solid portion of a main shaft according to an embodiment.

[0028] Fig.14D It is a diagram schematically showing an example of forging flow lines of a solid portion of a main shaft according to an embodiment.

[0029] Fig.15AIt is a diagram showing another example of the forging process according to the embodiment.

[0030] Fig. 15B It is a diagram showing another example of the forging process according to the embodiment.

[0031] Fig.16A It is a diagram showing another example of the cutting step according to the embodiment.

[0032] Fig. 16B It is a diagram showing another example of the cutting step according to the embodiment.

[0033] Fig. 16C It is a diagram schematically showing another example of the forging flow lines of the solid portion of the main shaft according to the embodiment.

[0034] Fig.16D It is a diagram schematically showing another example of the forging flow lines of the solid portion of the main shaft according to the embodiment.

[0035] Description of Reference Numerals

[0036] S10…Core manufacturing process, S20…Die arrangement process, S30…Forging process, S40…Cutting process, AX…Rotating axis, 1…Impact tool, 2…Casing, 2L…Left casing, 2R…Right casing, 2S, 3S, 30S…Screws, 3…Rear cover, 4…Hammer case, 4A…Large cylinder, 4B…Small cylinder, 6…Motor, 7…Reduction mechanism, 8…Spindle, 8A…Spindle shaft, 8B…First flange, 8C…Second flange, 8D…Connecting portion, 8E…Cylinder, 8F…Spindle boss, 8G…Spindle groove, 8H…Insertion hole, 8I…Slit, 8J…Cutting surface, 8K ...non-cutting part, 8L...flange, 8S...outer peripheral surface, 8T...forging streamline, 9...striking mechanism, 10...anvil, 10A...anvil shaft, 10B...anvil protrusion, 10C...tool hole, 10D...anvil recess, 11...tool holding mechanism, 12...fan, 12A...sleeve, 13...battery mounting part, 14...trigger shifter, 15...forward / reverse switching shifter, 16...interface panel, 16A...operation button, 17...manual mode switching button, 18...light assembly, 19...air inlet, 20...exhaust port, 21...motor storage part, 22...handle, 23...battery holding part, 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 substrate, 36…Fuse terminal, 37…Rear rotor bearing, 38…Front rotor bearing, 41…Pinion gear, 42…Planet gear, 42P…Pin, 43…Internal gear, 44…Spindle bearing, 45…O-ring, 46…Anvil bearing, 47…Hammer, 47A…Main body, 47 C…inner cylinder, 47D…hammer protrusion, 47E…recess, 47G…hammer groove, 47S…inner circumferential surface, 48, 54…balls, 49…coil spring, 50, 56…washers, 51…hammer housing cover, 52…buffer, 57…support member, 60…inner space, 70…core, 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…core supporting portion, 82…slit corresponding portion, 83…accommodating portion, 84…claw, 85…forging hammer DETAILED DESCRIPTION

[0037] In one or more embodiments, the impact tool may have: a motor; a sun gear, which is rotated by the motor; at least three planetary gears, which are meshed with the sun gear; an internal gear, which is meshed with the planetary gears; a main shaft, which includes a flange portion and a shaft portion extending axially forward from the flange portion, wherein the flange portion has a hole for inserting the sun gear in the axial direction and has a slit portion for mounting the planetary gear on at least the side, and the flange portion is in a state formed by forging; a hammer, which is retained on the main shaft; an anvil, which is struck by the hammer in the rotation direction; a hammer housing, which accommodates the hammer and holds the anvil so as to be rotatable; a front end tool retaining portion, which is formed on the anvil; and a coil spring, which applies force to the hammer toward the anvil side.

[0038] According to the above configuration, the time required for manufacturing the impact tool can be shortened by utilizing the main shaft in which the flange portion is formed by forging.

[0039] In one or more embodiments, the flange portion may have a cut surface on at least a portion of its surface.

[0040] In the above configuration, the surface of the flange portion formed by forging can be appropriately cut as necessary, thereby improving the outer shape accuracy of the main shaft.

[0041] In one or more embodiments, the main shaft may further include a ball disposed between the main shaft and the hammer, and the main shaft may have a main shaft groove in which at least a part of the ball is disposed in the shaft portion.

[0042] According to the above configuration, when manufacturing a main shaft having a main shaft groove in which at least a part of the balls are arranged in the shaft portion, the time required for manufacturing can be shortened.

[0043] In one or more embodiments, the main shaft may be formed of iron containing 0.13% to 1.00% carbon and 0.90% or more chromium.

[0044] According to the above configuration, plastic deformation can be appropriately performed by forging, and strength after deformation can be ensured.

[0045] In one or more embodiments, the main axis may be formed at the flange portion from the radial center toward the outside based on a forging flow line of forging.

[0046] According to the above configuration, since the flange portion of the main shaft is in a state where the forging flow lines due to forging are formed from the radial center toward the outside, appropriate strength can be ensured.

[0047] In one or more embodiments, the main shaft may have: a first flange connected to the shaft portion; a second flange arranged behind the first flange and opposite to the first flange; and a connecting portion connecting the first flange and the second flange in the axial direction.

[0048] According to the above configuration, when manufacturing a main shaft having a structure including the first flange, the second flange, and the connecting portion, the time required for manufacturing can be shortened.

[0049] In one or more embodiments, a plurality of connection portions may be arranged in the circumferential direction, and the planetary gears may be arranged respectively between the connection portions adjacent to each other at a portion sandwiched between the first flange and the second flange.

[0050] According to the above configuration, when manufacturing a main shaft having a structure in which the planetary gears are respectively arranged between the connecting portions adjacent to each other at the portion sandwiched between the first flange and the second flange, the time required for manufacturing can be shortened.

[0051] In one or more embodiments, the main shaft may be formed so that a portion facing an opening surrounded by the first flange, the second flange, and the plurality of connection portions is a non-cutting portion.

[0052] According to the above configuration, the opening of the slit portion can be formed by the non-cut portion, and therefore, cutting processing is not required when forming the opening.

[0053] In one or more embodiments, the spindle can be a spindle used for an electric tool, comprising: a flange portion having a hole in the axial direction for inserting a sun gear and a slit portion on at least the side for installing a planetary gear; and a shaft portion extending forward from the flange portion, and the flange portion can be in a state of being formed by forging.

[0054] According to the above configuration, since the flange portion is formed by forging, the time required for manufacturing the main shaft can be shortened.

[0055] In one or more embodiments, the flange portion may have a cut surface on at least a portion of its surface.

[0056] According to the above configuration, the surface of the flange portion formed by forging is appropriately cut as necessary, thereby improving the outer shape accuracy of the main shaft.

[0057] In one or more embodiments, the shaft portion may include a main shaft groove in which at least a portion of the balls are disposed.

[0058] According to the above configuration, when manufacturing a main shaft having a main shaft groove in which at least a part of the balls are arranged in the shaft portion, the time required for manufacturing can be shortened.

[0059] In one or more embodiments, the main shaft may be formed of iron containing 0.13% to 1.00% carbon and 0.90% or more chromium.

[0060] According to the above configuration, plastic deformation can be appropriately performed by forging, and strength after deformation can be ensured.

[0061] In one or more embodiments, the flange portion may be formed from the radial center toward the outside based on a forging flow line of forging.

[0062] According to the above configuration, since the flange portion is in a state where forging flow lines due to forging are formed from the radial center toward the outside, appropriate strength can be ensured.

[0063] In one or more embodiments, the flange portion may have: a first flange connected to the shaft portion; a second flange arranged behind the first flange and opposite to the first flange; and a connecting portion connecting the first flange and the second flange in the axial direction.

[0064] According to the above configuration, when manufacturing a main shaft having a structure including the first flange, the second flange, and the connecting portion, the time required for manufacturing can be shortened.

[0065] In one or more embodiments, a plurality of connection portions may be arranged in the circumferential direction, and the planetary gears may be arranged respectively between the connection portions adjacent to each other at a portion sandwiched between the first flange and the second flange.

[0066] According to the above configuration, when manufacturing a main shaft having a structure in which the planetary gears are respectively arranged between the connecting portions adjacent to each other at the portion sandwiched between the first flange and the second flange, the time required for manufacturing can be shortened.

[0067] In one or more embodiments, the flange portion may be formed such that a portion facing an opening portion surrounded by the first flange, the second flange, and the plurality of connection portions is a non-cut portion.

[0068] According to the above configuration, since the opening of the slit portion can be formed by the non-cut portion, it is not necessary to perform cutting work when forming the opening.

[0069] In one or more embodiments, the manufacturing method of a spindle is a manufacturing method of a spindle for an electric tool, the spindle comprising: a flange portion having a hole in the axial direction for inserting a sun gear and a slit portion on at least the side for installing a planetary gear; and a shaft portion extending forward from the flange portion, wherein the manufacturing method may include the following steps: a step of forming an iron core having a flange corresponding portion and a shaft corresponding portion corresponding to the flange portion and the shaft portion, respectively; a step of configuring a mold having a slit corresponding portion corresponding to the slit portion relative to the flange corresponding portion of the iron core; and a step of forming the slit portion by forging in a state in which the mold is configured, i.e., forging in which the rear end portion of the flange corresponding portion is struck in the axial direction to cause the flange corresponding portion to undergo plastic deformation along the slit corresponding portion of the mold.

[0070] According to the above structure, in a state where a die having a slit corresponding portion corresponding to the slit portion is arranged relative to the flange corresponding portion of the core, the slit portion is formed by forging by tapping the rear end of the flange corresponding portion in the axial direction so that the flange corresponding portion is plastically deformed along the slit corresponding portion of the die. Therefore, the slit portion can be effectively formed by forging, and thus the time required for manufacturing the main shaft can be shortened.

[0071] In one or more embodiments, the flange portion of the main shaft has a hole in the axial direction for inserting the sun gear, and may further include the following step: after plastically deforming the flange corresponding portion, cutting the flange corresponding portion to form the hole.

[0072] According to the above configuration, since the hole is formed by cutting after the slit portion is formed by forging, the time required for manufacturing the main shaft can be shortened compared to the case where both the slit portion and the hole are formed by cutting.

[0073] In one or more embodiments, the core may be formed by forging when the material temperature is between -20°C and 40°C, between 300°C and 850°C, or between 1000°C and 1250°C, and the spindle may be formed by forging when the temperature of the formed core is between -20°C and 40°C. When the core is forged, any temperature may be used as long as the temperature of the core is between -20°C and 1250°C.

[0074] According to the above configuration, the core can be appropriately manufactured, and the main shaft can be appropriately manufactured using the appropriately manufactured core.

[0075] In one or more embodiments, the main shaft may be formed so that the surface hardness is 300 HV or more by heat treatment after being formed by forging.

[0076] According to the above structure, since the surface hardness reaches 300 HV or more by heat treatment after forging, the strength of the main shaft 8 can be ensured. In addition, as a heat treatment, any treatment can be used as long as it is a treatment that can change the properties of the material, such as overall quenching, carburizing quenching, carbonitriding quenching, high-frequency quenching, or aging hardening treatment.

[0077] Hereinafter, the embodiments of the present disclosure will be described with reference to the accompanying drawings, but the present disclosure is not limited to the embodiments. The structural elements of the embodiments described below can be combined as appropriate. In addition, some structural elements may not be used.

[0078] In the embodiments, the positional relationship of each part is described using the terms left, right, front, rear, top, and bottom. The above terms represent relative positions or directions with respect to the center of the electric tool.

[0079] In the embodiments, a direction parallel to a rotation axis AX of the motor is appropriately referred to as an axial direction, a direction around the rotation axis AX is appropriately referred to as a circumferential direction or a rotation direction, and a radial direction from the rotation axis AX is appropriately referred to as a radial direction.

[0080] In the embodiment, the rotation axis AX extends along the front-to-back direction. The axial direction coincides with the front-to-back direction. One side of the axial direction is the front, and the other side of the axial direction is the rear. In addition, in the radial direction, a position closer to the rotation axis AX or a direction close to the rotation axis AX is appropriately referred to as the radial inner side, and a position farther from the rotation axis AX or a direction away from the rotation axis AX is appropriately referred to as the radial outer side.

[0081] Figure 1 1 is a perspective view showing the impact tool 1 according to the embodiment when viewed from the front. Figure 2 It is a side view showing the upper part of the impact tool 1 according to the embodiment. Figure 3 1 is a longitudinal sectional view showing an upper portion of the impact tool 1 according to the embodiment. Figure 4 It is a transverse cross-sectional view showing an upper portion of the impact tool 1 according to the embodiment. Figure 5 It is a right side view showing the impact tool 1 according to the embodiment.

[0082] In the embodiment, an impact tool 1 is cited as an example of an electric tool for description. In the embodiment, the impact tool 1 is an impact screwdriver as a type of screw fastening tool. The impact tool 1 includes a housing 2, a rear cover 3, a hammer housing 4, a bearing box 24, a hammer housing cover 51, a buffer 52, a motor 6, a speed reduction mechanism 7, a spindle 8, a striking mechanism 9, an anvil 10, a tool holding mechanism 11, a fan 12, a battery assembly 13, a trigger shifter 14, a forward and reverse switching shifter 15, an interface panel 16, a manual mode switching button 17, and a light assembly 18.

[0083] The housing 2 is made of synthetic resin. In the embodiment, the housing 2 is made of nylon. The housing 2 includes: a left housing 2L; and a right housing 2R, which is arranged on the right side of the left housing 2L. The left housing 2L and the right housing 2R are fixed by a plurality of screws 2S. The housing 2 is composed of a pair of half-split housings.

[0084] The housing 2 includes a motor housing portion 21 , a grip portion 22 , and a battery holding portion 23 .

[0085] The motor housing portion 21 houses the motor 6. The motor housing portion 21 houses at least a portion of the hammer case 4. The motor housing portion 21 has a cylindrical shape.

[0086] The grip portion 22 is gripped by the operator. The grip portion 22 extends downward from the motor housing portion 21. The trigger lever 14 is provided on the upper portion of the grip portion 22.

[0087] The battery holding portion 23 holds the battery pack 25 via the battery mounting portion 13. The battery holding portion 23 is connected to the lower end of the grip portion 22. The outer dimensions of the battery holding portion 23 are larger than those of the grip portion 22 in the front-rear direction and the left-right direction.

[0088] The rear cover 3 is configured to cover the opening of the rear end portion of the motor housing portion 21. The rear cover 3 is configured to the rear of the motor housing portion 21. The rear cover 3 accommodates at least a portion of the fan 12. The fan 12 is configured inside the rear cover 3. The rear cover 3 holds the rear rotor bearing 37. The rear cover 3 is made of synthetic resin. The rear cover 3 is fixed to the rear end portion of the motor housing portion 21 by two screws 3S.

[0089] The motor housing portion 21 has an air inlet 19. The rear cover 3 has an air outlet 20. The air in the external space of the housing 2 flows into the internal space of the housing 2 through the air inlet 19. The air in the internal space of the housing 2 flows out to the external space of the housing 2 through the air outlet 20.

[0090] The hammer housing 4 accommodates at least a portion of the speed reduction mechanism 7, the spindle 8, the striking mechanism 9, and at least a portion of the anvil 10. The hammer housing 4 is made of metal. In the embodiment, the hammer housing 4 is made of aluminum. The hammer housing 4 is cylindrical. The hammer housing 4 is connected to the front portion of the motor housing portion 21. The bearing box 24 is fixed to the rear portion of the hammer housing 4. The bearing box 24 accommodates at least a portion of the speed 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 portion of the hammer housing 4.

[0091] The hammer case 4 is sandwiched between the left housing 2L and the right housing 2R. The rear portion of the hammer case 4 is accommodated in the motor accommodation portion 21. The hammer case 4 is connected to the front portion of the motor accommodation portion 21. The bearing box 24 is fixed to the motor accommodation portion 21 and the hammer case 4, respectively.

[0092] The hammer case cover 51 protects the hammer case 4. The hammer case cover 51 can suppress contact between the hammer case 4 and an object around the hammer case 4. The hammer case cover 51 is arranged to cover the outer peripheral surface of the large cylinder portion 4A.

[0093] The buffer 52 protects the hammer case 4. The buffer 52 can suppress the contact between the hammer case 4 and an object around the hammer case 4. The buffer 52 can alleviate the impact when the hammer case 4 contacts an object. The buffer 52 is arranged around the small cylinder portion 4B.

[0094] 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 housing portion 21. At least a portion of the rotor 27 is arranged inside the stator 26. The rotor 27 rotates relative to the stator 26. The rotor 27 rotates around a rotation axis AX extending in the front-rear direction.

[0095] The stator 26 includes a stator core 28 , a rear insulator 29 , a front insulator 30 , and a coil 31 .

[0096] The stator core 28 includes a plurality of stacked steel plates. The steel plates are metal plates mainly composed of iron. The stator core 28 is cylindrical. The stator core 28 is arranged radially outward of the rotor 27. The stator core 28 has a plurality of teeth that support the coil 31.

[0097] The rear insulator 29 and the front insulator 30 are respectively electrical insulating components made of synthetic resin. The rear insulator 29 and the front insulator 30 respectively electrically insulate the stator core 28 and 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 configured to cover a portion of the surface of the teeth. The front insulator 30 is configured to cover a portion of the surface of the teeth.

[0098] The coil 31 is mounted on the stator core 28 via the rear insulator 29 and the front insulator 30. A plurality of coils 31 are provided. The coil 31 is arranged around the teeth of the stator core 28 via the rear insulator 29 and the front insulator 30. The coil 31 and the stator core 28 are electrically insulated by the front insulator 30 and the rear insulator 29. The plurality of coils 31 are connected via the fuse terminal 36.

[0099] The rotor 27 rotates around the rotation axis AX. The rotor 27 includes a rotor core 32, a rotor shaft 33, a rotor magnet 34A, and a sensor magnet 34B.

[0100] The rotor core 32 and the rotor shaft 33 are made of steel. In the embodiment, the rotor core 32 and the rotor shaft 33 are integrated. The rear portion of the rotor shaft 33 protrudes backward from the rear end surface of the rotor core 32. The front portion of the rotor shaft 33 protrudes forward from the front end surface of the rotor core 32.

[0101] The rotor magnet 34A is fixed to the rotor core 32. In the embodiment, the rotor magnet 34A is arranged around the rotor core 32. The sensor magnet 34B is fixed to the rotor core 32. In the embodiment, the sensor magnet 34B is arranged on the front end surface of the rotor core 32.

[0102] The sensor substrate 35 is mounted on the front insulator 30. The sensor substrate 35 is fixed to the front insulator 30 by screws 30S. The sensor substrate 35 includes: a circular circuit substrate; and a rotation detection element supported by the circuit substrate. At least a portion of the sensor substrate 35 faces the front end surface of the sensor magnet 34B. The rotation detection element detects the position of the rotor 27 in the rotation direction by detecting the position of the sensor magnet 34B.

[0103] 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.

[0104] The front end portion of the rotor shaft 33 is arranged in the internal space of the hammer case 4 through an opening provided in the rear annular portion 24A of the bearing box 24 .

[0105] A pinion gear (sun gear) 41 is formed at the front end portion of the rotor shaft 33. The pinion gear 41 is coupled to at least a portion of the speed reduction mechanism 7. The rotor shaft 33 is coupled to the speed reduction mechanism 7 via the pinion gear 41.

[0106] The speed reduction mechanism 7 connects the rotor shaft 33 and the main shaft 8. The gears of the speed reduction mechanism 7 are driven by the rotor 27. The speed reduction mechanism 7 transmits the rotation of the rotor 27 to the main shaft 8. The speed reduction mechanism 7 rotates the main shaft 8 at a rotation speed lower than the rotation speed of the rotor shaft 33. The speed reduction mechanism 7 is arranged at a position further forward than the stator 26. The speed reduction mechanism 7 includes a planetary gear mechanism.

[0107] The speed reduction mechanism 7 includes: 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 respectively accommodated in the hammer housing 4. The plurality of planetary gears 42 mesh with the pinion gear 41. The planetary gear 42 is rotatably supported on the main shaft 8 by means of a pin 42P. The main shaft 8 rotates through the planetary gear 42. The internal gear 43 includes: internal teeth meshing with the planetary gear 42.

[0108] The internal gear 43 is fixed to the large cylinder portion 4A of the hammer case 4. The internal gear 43 is always non-rotatable relative to the hammer case 4.

[0109] 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. The main shaft 8 connected to the planetary gear 42 via the pin 42P rotates at a rotation speed lower than the rotation speed of the rotor shaft 33 due to the revolution of the planetary gear 42.

[0110] Figure 5 It is an exploded perspective view showing a main part of the impact tool 1 according to the embodiment. Figure 6 It is a bottom view showing the main shaft 8 according to the embodiment. Fig. 7A and Figure 7B A diagram schematically showing forging flow lines of a solid portion of a main shaft 8 according to an embodiment. Figure 8 This is a diagram showing a main shaft 8 according to the embodiment as seen from the side.

[0111] 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 is rotated 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 the ball 48 and the hammer 47. At least a portion of the spindle 8 is arranged: in front of the motor 6. The spindle 8 is arranged: in front of the stator 26. At least a portion of the spindle 8 is arranged: in front of the rotor 27. At least a portion of the spindle 8 is arranged: in front of the reduction mechanism 7. At least a portion of the spindle 8 is arranged: in the rear of the anvil 10.

[0112] The main shaft 8 has a main shaft portion 8A and a flange portion 8L.

[0113] The spindle shaft portion 8A is in the shape of a rod that is 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 that protrudes forward from the front end of the spindle shaft portion 8A.

[0114] The flange portion 8L includes 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 portion of the outer peripheral surface of the main shaft shaft portion 8A. The second flange portion 8C is arranged at a position further rearward than 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 41. The insertion hole 8H is arranged in the center of the second flange portion 8C in the up-down direction and the left-right direction.

[0115] 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 on the side surface of the flange portion 8L.

[0116] 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 the side of the flange portion 8L. In the present embodiment, a plurality of 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 supported by the pin 42P in a rotatable manner on the first flange portion 8B and the second flange portion 8C. The planetary gear 42 is respectively arranged between the connecting portions 8D adjacent to each other at the portion sandwiched by the first flange portion 8B and the second flange portion 8C.

[0117] Spindle bearing 44 (refer to Figure 4The main shaft bearing 44 is arranged inside the cylindrical portion 8E of the main shaft 8 that protrudes rearward from the rear surface of the second flange portion 8C. The main shaft bearing 44 holds the cylindrical portion 8E of the main shaft 8. The main shaft bearing 44 is held by the bearing box 24.

[0118] In this embodiment, the flange portion 8L of the main shaft 8 is formed by forging. Fig. 7A and Figure 7B As shown, the main shaft 8 has forging flow lines 8T formed thereon in a cross-sectional view, which are generated by forging. Fig. 7A The forging flow lines when forging is performed by the upset forging method described later are shown. Figure 7B The forging flow lines are shown when forging is performed by the rear extrusion method described later. Fig. 7A and Figure 7B As shown in FIG. 1 , a forged streamline 8T is formed from the radial center toward the outside at the first flange portion 8B, the second flange portion 8C, the connecting portion 8D, and the cylindrical portion 8E of the flange portion 8L. Fig. 7A In the example shown, a forged streamline 8T is formed in the cylindrical portion 8E along the radial direction. The forged streamline 8T formed in the cylindrical portion 8E is formed in a state of being separated from other portions such as the second flange portion 8C. Figure 7B In the example shown, the forging streamline 8T is formed to be continuous from the cylindrical portion 8E to the second flange portion 8C. Thus, the shape of the forging streamline 8T formed in the flange portion 8L is different when forging is performed by upset forging and when forging is performed by rear extrusion.

[0119] The portion of the main shaft 8 facing the opening surrounded by the first flange portion 8B, the second flange portion 8C and the plurality of connecting portions 8D is a non-cut portion 8K. The non-cut portion 8K is a portion that is not subjected to cutting processing on the surface formed by forging. The main shaft 8 is in a state where the portion other than the non-cut portion 8K is subjected to cutting processing. In this way, since the opening of the slit portion 8I can be formed by the non-cut portion 8K, it is not necessary to perform cutting processing when forming the opening.

[0120] The main shaft 8 is formed of iron containing 0.13% or more and 1.00% or less of carbon and 0.90% or more of chromium. Alternatively, the main shaft 8 may be formed of iron containing at least carbon, chromium, and molybdenum. With this structure, plastic deformation can be appropriately performed by forging, thereby ensuring strength after deformation.

[0121] 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 speed reduction mechanism 7 and the main shaft 8. The striking mechanism 9 strikes the anvil 10 in the rotational direction based on the rotational force of the main shaft 8 rotated by the motor 6. The striking mechanism 9 includes 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 accommodated in the large cylinder 4A of the hammer housing 4.

[0122] The hammer 47 is arranged at a position forward of the speed reduction mechanism 7. The hammer 47 is arranged around the main shaft 8. The hammer 47 is arranged around the main shaft shaft portion 8A. The hammer 47 is held by the main shaft shaft portion 8A. The ball 48 is arranged between the main shaft 8 and the hammer 47.

[0123] The hammer 47 is rotated by the motor 6. The rotational force of the motor 6 is transmitted to the hammer 47 via the speed 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 are consistent. The hammer 47 rotates around the rotation axis AX.

[0124] The washer 50 is arranged inside the recessed portion 47E. The washer 50 is supported by the hammer 47 via a plurality of balls 54. The balls 54 are arranged in front of the washer 50. The balls 54 are arranged between the rear surface of the main body 47A and the front surface of the washer 50.

[0125] The coil spring 49 is arranged around the spindle shaft 8A. The rear end of the coil spring 49 is supported by the first flange 8B. The front end of the coil spring 49 is arranged inside the recess 47E and supported by the washer 50. The coil spring 49 always generates an elastic force that moves the hammer 47 forward.

[0126] The ball 48 is made of metal such as steel. The ball 48 is arranged between the main shaft portion 8A and the main body portion 47A. The main shaft portion 8A has a main shaft groove 8G in which at least a part of the ball 48 is arranged. The main shaft groove 8G is provided in a part of the outer peripheral surface of the main shaft portion 8A. The hammer 47 has a hammer groove 47G in which at least a part of the ball 48 is arranged. The hammer groove 47G is provided in a part of the inner peripheral surface of the main body portion 47A and the inner cylinder portion 47C.

[0127] Two balls 48 are provided. Two spindle grooves 8G are provided on the outer circumference of the spindle shaft portion 8A. Two hammer grooves 47G are provided on the inner circumference of the main body portion 47A and the inner tube portion 47C. One ball 48 is arranged between one spindle groove 8G and one hammer groove 47G. Another ball 48 is arranged between another spindle groove 8G and another hammer groove 47G. The ball 48 can roll on the inner side of the spindle groove 8G and the inner side of the hammer groove 47G respectively. The hammer 47 can move 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 the movable range defined by the spindle groove 8G and the hammer groove 47G.

[0128] The anvil 10 is arranged at a position forward of the motor 6. The anvil 10 is an output portion 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 arranged at a position forward of the spindle 8. At least a portion of the anvil 10 is arranged at a position forward of the hammer 47. The anvil 10 is struck in the rotational direction by the hammer 47.

[0129] The anvil 10 has: an anvil shaft portion 10A and an anvil protrusion portion 10B. The anvil shaft portion 10A is: a rod-shaped portion that is longer in the front-to-back direction. The central axis of the anvil shaft portion 10A is consistent 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.

[0130] A tool hole 10C is provided at the front end face of the anvil 10. An anvil recess 10D is provided at the rear end face of the anvil 10. The tool hole 10C is formed to extend rearward from the front end face of the anvil shaft portion 10A. The front end tool is inserted into the tool hole 10C. The front end tool is assembled on the anvil 10. The anvil recess 10D is provided to be recessed from the rear end face of the anvil 10 toward the front. The spindle protrusion 8F is arranged on the anvil recess 10D.

[0131] The anvil 10 is supported by the anvil bearing 46 in a rotatable manner. 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 consistent. The anvil 10 rotates around the rotation axis AX. The anvil bearing 46 is arranged around the anvil shaft portion 10A. The O-ring 45 is arranged between the anvil bearing 46 and the anvil shaft portion 10A. The anvil bearing 46 is arranged on the inner side of the small cylinder portion 4B of the hammer housing 4. The anvil bearing 46 is retained in the small cylinder portion 4B of the hammer housing 4. The hammer housing 4 supports the anvil 10 with the aid of the anvil bearing 46. The anvil bearing 46 supports the front portion of the anvil shaft portion 10A so as to be rotatable. In the embodiment, two anvil bearings 46 are arranged in the front-to-back direction.

[0132] The gasket 56 is arranged in front of the anvil protrusion 10B. The gasket 56 can suppress the contact between the front surface of the anvil protrusion 10B and the hammer case 4. The support member 57 is arranged behind the anvil bearing 46. The support member 57 is arranged to contact the rear surface of the outer ring of the anvil bearing 46. The support member 57 is annular. The support member 57 can suppress the anvil bearing 46 from escaping from the small cylinder 4B toward the rear. The support member 57 is arranged in a groove provided on the inner peripheral surface of the small cylinder 4B.

[0133] The hammer protrusion 47D can contact the anvil protrusion 10B. When the hammer protrusion 47D is in contact with the anvil protrusion 10B, the motor 6 drives the anvil 10 to rotate together with the hammer 47 and the spindle 8.

[0134] The anvil 10 is struck in the rotation direction by the hammer 47. For example, during the screw tightening operation, if the load acting on the anvil 10 increases, sometimes a situation occurs in which the anvil 10 cannot be rotated only by the load of the coil spring 49. If the anvil 10 cannot be rotated only by the load of the coil spring 49, the rotation of the anvil 10 and the hammer 47 will stop. The spindle 8 and the hammer 47 can move relative to each other in the axial direction and the circumferential direction respectively by means of the ball 48. Even if the rotation of the hammer 47 stops, the spindle 8 continues to rotate by the power generated by the motor 6. In the state where the rotation of the hammer 47 stops, if the spindle 8 rotates, the ball 48 moves backward while being guided by the spindle groove 8G and the hammer groove 47G respectively. In the state where the rotation of the hammer 47 stops, when the spindle 8 rotates, the outer peripheral surface 8S of the spindle 8 and the inner peripheral surface 47S of the hammer 47 slide. The hammer 47 receives force from the ball 48 and moves backward along with the ball 48. That is, when the rotation of the anvil 10 is stopped, the hammer 47 moves backward by the rotation of the main shaft 8. The backward movement of the hammer 47 releases the contact between the hammer protrusion 47D and the anvil protrusion 10B.

[0135] As described above, the coil spring 49 always generates an elastic force that moves the hammer 47 forward. The hammer 47 that has moved to the rear is moved forward by the elastic force of the coil spring 49. When the hammer 47 moves forward, it receives a force in the rotation 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 contacts the anvil protrusion 10B while rotating. As a result, the anvil protrusion 10B is struck in the rotation direction by the hammer protrusion 47D of the hammer 47. Both the power of the motor 6 and the inertia force of the hammer 47 act on the anvil 10. Therefore, the anvil 10 can rotate around the rotation axis AX with a high torque.

[0136] The tool holding mechanism 11 is disposed around the front portion of the anvil 10. The tool holding mechanism 11 holds a tip tool inserted into the tool hole 10C of the anvil 10. The tool holding mechanism 11 can attach and detach the tip tool.

[0137] The fan 12 is arranged at a position further rearward than 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 portion of the rotor 27. The fan 12 is fixed to the rear of the rotor shaft 33 by means of a sleeve 12A. The fan 12 is arranged between the rear rotor bearing 37 and the stator 26. The fan 12 rotates by the rotation of the rotor 27. The fan 12 rotates together with the rotor shaft 33 by the rotation of the rotor shaft 33. The rotation of the fan 12 causes the air in the external space of the housing 2 to flow into the internal space of the housing 2 through the air inlet 19. The air flowing into the internal space of the housing 2 circulates in the internal space of the housing 2, thereby cooling the motor 6. The air circulating in the internal space of the housing 2 is rotated by the fan 12 and flows out to the external space of the housing 2 through the exhaust port 20.

[0138] The battery assembly portion 13 is arranged at the lower part of the battery holding portion 23. The battery assembly portion 13 is connected to the battery pack 25. The battery pack 25 is mounted on the battery assembly portion 13. The battery pack 25 can be detached from the battery assembly portion 13. The battery pack 25 is mounted on the battery assembly portion 13 by being inserted into the battery holding portion 23 from the front. The battery pack 25 is removed from the battery assembly portion 13 by pulling the battery pack 25 forward from the battery assembly portion 13. The battery pack 25 includes a secondary battery. In the embodiment, the battery pack 25 includes a rechargeable lithium-ion battery. The battery pack 25 can supply power to the impact tool 1 by being mounted on the battery assembly portion 13. The motor 6 is driven based on the power supplied from the battery pack 25.

[0139] The trigger paddle 14 is provided on the grip portion 22. The operator operates the trigger paddle 14 to start the motor 6. By operating the trigger paddle 14, the driving and stopping of the motor 6 are switched.

[0140] The forward / reverse switching lever 15 is provided at the upper part of the gripping portion 22. The forward / reverse switching lever 15 is operated by the 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.

[0141] 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 at a position further forward than the grip portion 22. The interface panel 16 has an operation button 16A. The operation button 16A may be one or more. In the embodiment, the operation button 16A is provided with a plurality of buttons. The operation mode of the motor 6 is switched by the operator operating the operation button 16A.

[0142] The manual mode switching button 17 is provided on the upper part of the trigger lever 14. The manual mode switching button 17 is operated by the operator. By operating the manual mode switching button 17, the control mode of the motor 6 is switched.

[0143] The lamp assembly 18 emits illumination light. The lamp assembly 18 illuminates the anvil 10 and the surroundings of the anvil 10 with the illumination light. The lamp assembly 18 illuminates the front of the anvil 10 with the illumination light. In addition, the lamp assembly 18 illuminates the front end tool mounted on the anvil 10 and the surroundings of the front end tool with the illumination light. In the embodiment, the lamp assembly 18 is respectively arranged on the left and right sides of the large cylinder portion 4A of the hammer housing 4.

[0144] The main shaft 8 has an internal space 60. An opening is provided at the rear end face of the main shaft 8. The internal space 60 is formed inside the main shaft 8 in a manner extending forward from the opening provided at the rear end face of the main shaft 8. Lubricating oil is contained in the internal space 60. The lubricating oil includes grease. The front end portion of the pinion 41 is inserted into the rear end portion of the internal space 60 through the opening at the rear end face of the main shaft 8.

[0145] Fig. 9 1 is a flow chart showing an example of a method for manufacturing the spindle 8 according to the embodiment. Fig. 9 As shown, the method for manufacturing the main shaft 8 includes: a core manufacturing step S10 , a die arrangement step S20 , a forging step S30 , a cutting step S40 , and a heat treatment step S50 .

[0146] In the core manufacturing step S10, the core 70 serving as the prototype of the main shaft 8 is formed. For example, the core 70 can be formed by forging or the like. In this case, the temperature of the core 70 can be formed to be greater than -20°C and less than 40°C (cold rolling forging), greater than 300°C and less than 850°C (warm rolling forging), or greater than 1000°C and less than 1250°C (hot rolling forging). In addition, in the core manufacturing step S10, the temperature of the core 70 can be any temperature as long as it is within the range of greater than -20°C and less than 1250°C.

[0147] Fig.101 is a diagram showing an example of a core 70 according to the embodiment. The core 70 includes a shaft corresponding portion 71 and a flange corresponding portion 72. The shaft corresponding portion 71 is a portion corresponding to the main shaft portion 8A of the main shaft 8.

[0148] The flange corresponding portion 72 is a portion corresponding to the flange portion 8L of the main shaft 8. The flange corresponding portion 72 has: a first flange corresponding portion 72B, which corresponds to the first flange portion 8B of the main shaft 8; and a connection corresponding portion 72D, which corresponds to the connection portion 8D of the main shaft 8. The first flange corresponding portion 72B is disc-shaped. The connection corresponding portion 72D is a shape in which a plate-like portion extends from the center of the axial direction toward three radial directions. The multiple connection corresponding portions 72D are configured so that the angles formed with adjacent connection corresponding portions 72D are equal angles (for example, 120°). In addition, the angles formed with the adjacent connection corresponding portions 72D by the multiple connection corresponding portions 72D may not be equal.

[0149] In the die placement step S20 , the forging die 80 is placed with respect to the core 70 . Fig.11 It is a diagram showing an example of a forging die 80 according to the embodiment. Fig.12 1 is a diagram showing an example of the mold configuration step S20 according to the embodiment. Fig.11 As shown, the forging die 80 includes a core support portion 81 and a slit corresponding portion 82. The core support portion 81 supports the core 70. The core support portion 81 includes a receiving portion 83 and a claw portion 84.

[0150] The receiving portion 83 receives the shaft corresponding portion 71 of the core 70 and the first flange corresponding portion 72B of the flange corresponding portion 72. The claw portion 84 supports the radial outer peripheral side surface of the connection corresponding portion 72D in the core 70 received in the receiving portion 83. Three claw portions 84 are arranged at equal intervals in the circumferential direction. When the core 70 is received in the receiving portion 83, the outer side ends of the three connection corresponding portions 72D of the core 70 are arranged opposite to the claw portion 84. The claw portion 84 positions the slit corresponding portion 82.

[0151] The slit corresponding portion 82 is a portion corresponding to the slit portion 8I of the main shaft 8. The slit corresponding portion 82 is composed of, for example, a plurality of fan-shaped plate-like members. The slit corresponding portion 82 is formed in a shape in which the inner peripheral portion corresponds to the connection corresponding portion 72D of the core 70. Fig.12 As shown, the slit corresponding portion 82 is disposed between the circumferentially adjacent claw portions 84 when the core 70 is accommodated in the accommodation portion 83. That is, the slit corresponding portion 82 is disposed so as to fill the space between the circumferentially adjacent connection corresponding portions 72D of the core 70.

[0152] In the forging step S30, in the state where the forging die 80 is arranged as described above, the rear end portion 72E of the flange corresponding portion 72 is struck in the axial direction so that the flange corresponding portion 72 is plastically deformed along the slit corresponding portion 82 of the forging die 80. The forging step S30 can be performed while setting the temperature of the core 70 to, for example, about 25° (cold forging).

[0153] Fig.13A and Fig. 13B 1 is a diagram showing an example of the forging step S30 according to the embodiment. Fig.13A As shown, in the forging step S30, the rear end portion 72E is hammered (upsetting method) using a forging hammer having a diameter larger than that of the flange corresponding portion 72. Fig. 13B As shown, the entire rear end portion 72E of the flange corresponding portion 72 is flattened, and the rear end portion 72E can be plastically deformed in a manner that it expands in the radial direction along the slit corresponding portion 82. The flattened and expanded portion becomes the second flange corresponding portion 72C corresponding to the second flange portion 8C and the cylindrical portion 8E of the main shaft 8. In addition, the slit portion 8I is formed in the portion where the slit corresponding portion 82 is arranged. After the flange corresponding portion 72 is plastically deformed, the slit corresponding portion 82 is removed, and the core 70 is taken out from the accommodating portion 83.

[0154] In the cutting step S40 , the flange corresponding portion 72 of the core 70 is cut after the flange corresponding portion 72 is plastically deformed. Fig.14A and Fig. 14B 1 is a diagram showing an example of the cutting step S40 according to the embodiment. Fig.14A and Fig. 14B As shown, in the cutting process S40, for example, the radial inner portion of the connection corresponding portion 72D is cut, and the radial outer portion is retained, thereby forming the connection portion 8D of the main shaft 8, and the slit portion 8I is continuous in the radial inner portion. In addition, by cutting the second flange corresponding portion 72C, the second flange portion 8C, the cylindrical portion 8E and the insertion hole 8H are formed. The shaft corresponding portion 71 and the first flange corresponding portion 72B can be kept as the main shaft shaft portion 8A and the first flange portion 8B. In addition, the outer periphery of the first flange corresponding portion 72B and the connection corresponding portion 72D can be cut as needed, thereby adjusting the outer shape of the first flange portion 8B and the connection portion 8D. The cutting process S40 forms a cutting surface 8J on the surface of the cut portion. In addition, 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 plurality of connection portions 8D is referred to as a non-cut portion 8K. Fig. 14C and Fig.14D It is a diagram schematically showing another example of the forging flow lines of the solid portion of the main shaft 8 according to the embodiment. Fig. 14C and Fig.14D An example of forging streamlines of the core 70 before and after cutting is shown in the single-dot chain frame. Fig. 14C and Fig.14D As shown, when forging is performed by upset forging, a forging streamline is formed in a manner that expands radially from the rear end of the rear end portion 72E toward the front. Cutting is performed from the state in which the forging streamline is formed in this way, and the forging streamline of the cylindrical portion 8E is separated from other portions.

[0155] Fig.15A and Fig. 15B 2 is a diagram showing another example of the forging step S30 according to the embodiment. Fig.15A and Fig. 15B As shown, in the forging process S30, the radial outer side of the flange corresponding part 72 can be surrounded by a different die 86, and the central part of the rear end part 72E can be struck by a forging hammer 85 having a diameter smaller than that of the flange corresponding part 72 (rear extrusion method). In this case, the central part of the rear end part 72E of the flange corresponding part 72 can be flattened in a manner concave relative to the peripheral part, and the rear end part 72E can be plastically deformed in a manner that the peripheral part rises toward the rear along the inner circumference of the die (raised part 72F). By forging in a rear extrusion method, the radial outer peripheral shape of the part that becomes the second flange corresponding part 72C can be formed into a shape along the die. In addition, the rear end part 72E formed with the raised part 72F becomes: a shape along the cylindrical part 8E.

[0156] Fig.16A and Fig. 16B 1 is a diagram showing another example of the cutting step S40 according to the embodiment. In the case where the forging step S30 is performed by the rear extrusion method, in the cutting step S40, as shown in FIG. Fig.16A and Fig. 16BAs shown, 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 main shaft 8, and the slit portion 8I is continuous in the radial inner portion. In addition, the second flange corresponding portion 72C is cut from the state where 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 kept as the main shaft shaft portion 8A and the first flange portion 8B. In addition, the outer periphery of the first flange corresponding portion 72B and the connection corresponding portion 72D can be cut as needed, thereby adjusting the outer shape of the first flange portion 8B and the connection portion 8D. Through the cutting step S40, a cutting surface 8J is formed on the surface of the cut portion. In addition, 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 plurality of connection portions 8D is referred to as a non-cut portion 8K. Fig. 16C and Fig.16D It is a diagram schematically showing another example of the forging flow lines of the solid portion of the main shaft 8 according to the embodiment. Fig. 16C and Fig.16D An example of forging streamlines of the core 70 before and after cutting is shown in the single-dot chain frame. Fig. 16C and Fig.16D As shown in the figure, when forging is performed by the rear extrusion method, a forging streamline is formed in a curved manner from the center of the rear end portion 72E to the rear end of the raised portion 72F. From the state where the forging streamline is formed in this way, the raised portion 72F is cut to form the cylindrical portion 8E, thereby forming a state where the forging streamline is continuous from the radial center of the rear end portion of the second flange portion 8C to the cylindrical portion 8E.

[0157] In the heat treatment step S50, the cut core 70 is heat treated. In the heat treatment step S50, the core 70 is heated so that the surface hardness of the cut core 70 reaches 300 HV or more. In the heat treatment step S50, any treatment may be used as long as the core 70 is heated in such a manner as to change the properties of the material of the core 70, such as full quenching, carburizing quenching, carbonitriding quenching, high frequency quenching, or aging hardening.

[0158] Next, the operation of the impact tool 1 will be described. For example, when a screw-tightening operation is performed on an object to be worked on, a front end tool (screwdriver bit) for the screw-tightening operation is inserted into the tool hole 10C of the anvil 10. The front end tool inserted into the tool hole 10C is held by the tool holding mechanism 11. After the front end tool is mounted on the anvil 10, the operator holds the grip 22 with, for example, the right hand, and pulls the trigger paddle 14 with the index finger of the right hand. When the trigger paddle 14 is pulled, power is supplied from the battery pack 25 to the motor 6, thereby starting the motor 6 and lighting the lamp assembly 18. The rotor shaft 33 of the rotor 27 is rotated by the start of the motor 6. 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 rotates while revolving around the pinion gear 41 while meshing with the internal teeth of the internal gear 43. The planetary gear 42 is rotatably supported by the main shaft 8 via the pin 42P. The main shaft 8 is rotated at a rotation speed lower than the rotation speed of the rotor shaft 33 by the revolution of the planetary gear 42.

[0159] 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. The rotation of the anvil 10 allows the screw tightening operation to be performed.

[0160] When a load exceeding a specified value acts on the anvil 10 due to the screw tightening operation, the rotation of the anvil 10 and the hammer 47 stops. When the main shaft 8 rotates while the rotation of the hammer 47 stops, the hammer 47 moves backward. The contact between the hammer protrusion 47D and the anvil protrusion 10B is released by the movement of the hammer 47 backward. The hammer 47 moving backward rotates and moves forward due to the elastic force of the coil spring 49. The anvil 10 is struck in the rotation direction by the hammer 47 while the hammer 47 rotates and moves forward. As a result, the anvil 10 rotates around the rotation axis AX with a higher torque. Therefore, the screw can be tightened to the work object with a higher torque.

[0161] As described above, in the present embodiment, the impact tool 1 may include: a motor 6; a pinion 41, which is rotated by the motor 6; at least three planetary gears 42, which mesh with the pinion 41; an internal gear 43, which meshes with the planetary gears 42; a spindle 8, which includes a flange portion 8L and a spindle shaft portion 8A extending axially forward from the flange portion 8L, wherein the flange portion 8L has an insertion hole 8H for inserting the pinion 41 in the axial direction and has a slit portion 8I for mounting the planetary gear 42 at least on the side, and the flange portion 8L is in a state formed by forging; a hammer 47, which is retained on the spindle 8; an anvil 10, which is struck in the rotation direction by the hammer 47; a hammer housing 4, which accommodates the hammer 47 and retains the anvil 10 to be rotatable; a front end tool retaining portion, which is formed on the anvil 10; and a coil spring 49, which applies force to the hammer 47 toward the anvil 10 side.

[0162] According to the above configuration, by using the main shaft 8 in which the flange portion 8L is formed by forging, the time required for manufacturing the impact tool 1 can be shortened.

[0163] In the present embodiment, the flange portion 8L may have a cut surface 8J in at least a portion of the surface.

[0164] According to the above configuration, the surface of the flange portion 8L formed by forging can be cut appropriately as necessary, thereby improving the outer shape accuracy of the main shaft 8 .

[0165] In the present embodiment, the ball 48 disposed between the spindle 8 and the hammer 47 may be further provided, and the spindle 8 may have a spindle groove 8G in which at least a part of the ball 48 is disposed in the spindle shaft portion 8A.

[0166] According to the above configuration, when manufacturing the spindle 8 having the spindle groove 8G in which at least a part of the balls 48 are arranged in the spindle shaft portion 8A, the time required for manufacturing can be shortened.

[0167] In the present embodiment, the main shaft 8 may be formed of iron containing 0.13% to 1.00% of carbon and 0.90% or more of chromium.

[0168] According to the above configuration, plastic deformation can be appropriately performed by forging, and strength after deformation can be ensured.

[0169] In the present embodiment, the main shaft 8 may be formed in the flange portion 8L along a forging flow line 8T of forging from the center in the radial direction toward the outside.

[0170] According to the above configuration, since the flange portion 8L of the main shaft 8 is formed in a state where the forging flow lines 8T due to forging are formed from the radial center toward the outside, appropriate strength can be ensured.

[0171] In this embodiment, the main shaft 8 can have: a first flange portion 8B, which is connected to the main shaft shaft portion 8A; a second flange portion 8C, which is arranged behind the first flange portion 8B and opposite to the first flange portion 8B; and a connecting portion 8D, which connects the first flange portion 8B and the second flange portion 8C in the axial direction.

[0172] According to 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.

[0173] In the present embodiment, a plurality of connection portions 8D may be arranged in the circumferential direction, and the planetary gears 42 may be arranged between adjacent connection portions 8D at a portion sandwiched between the first flange portion 8B and the second flange portion 8C.

[0174] According to the above configuration, when manufacturing the main shaft 8 having the structure in which the planetary gears 42 are respectively arranged between the adjacent connection portions 8D at the portion sandwiched between the first flange portion 8B and the second flange portion 8C, the time required for manufacturing can be shortened.

[0175] In the present embodiment, the main shaft 8 may be formed such that a portion facing the opening surrounded by the first flange portion 8B, the second flange portion 8C, and the plurality of connection portions 8D is the non-cutting portion 8K.

[0176] According to the above configuration, the opening of the slit portion 8I can be formed by the non-cut portion 8K, and therefore, it is not necessary to perform cutting work when forming the opening.

[0177] In the present embodiment, the spindle 8 is a spindle 8 used for an electric tool, and may include: a flange portion 8L, which has an insertion hole 8H in the axial direction for inserting the pinion 41, and has a slit portion 8I for mounting the planetary gear 42 at least on the side; and a spindle shaft portion 8A, which extends forward from the flange portion 8L, and the flange portion 8L is in a state formed by forging.

[0178] According to the above configuration, since the flange portion 8L is formed by forging, the time required for manufacturing the main shaft 8 can be shortened.

[0179] In the present embodiment, the flange portion 8L may have a cut surface in at least a portion of the surface.

[0180] According to the above configuration, the surface of the flange portion 8L formed by forging can be cut appropriately as necessary, thereby improving the outer shape accuracy of the main shaft 8 .

[0181] In the present embodiment, the spindle shaft portion 8A may include a spindle groove 8G in which at least a part of the balls 48 are arranged.

[0182] According to the above configuration, when manufacturing the spindle 8 having the spindle groove 8G in which at least a part of the balls 48 are arranged in the spindle shaft portion 8A, the time required for manufacturing can be shortened.

[0183] In the present embodiment, the steel sheet may be formed using iron containing 0.13% to 1.00% of carbon and 0.90% or more of chromium.

[0184] According to the above configuration, plastic deformation can be appropriately performed by forging, and strength after deformation can be ensured.

[0185] In the present embodiment, the flange portion 8L can be formed from the radial center toward the outer side based on the forging flow line 8T of the forging.

[0186] According to the above configuration, in the flange portion 8L, a forging flow line 8T due to forging is formed from the center in the radial direction toward the outside, so that appropriate strength can be ensured.

[0187] In this embodiment, the flange portion 8L can have: a first flange portion 8B, which is connected to the main shaft portion 8A; a second flange portion 8C, which is configured to be behind the first flange portion 8B and opposite to the first flange portion 8B; and a connecting portion 8D, which connects the first flange portion 8B and the second flange portion 8C in the axial direction.

[0188] According to 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.

[0189] In the present embodiment, a plurality of connection portions 8D may be arranged in the circumferential direction, and the planetary gears 42 may be arranged between adjacent connection portions 8D at a portion sandwiched between the first flange portion 8B and the second flange portion 8C.

[0190] According to the above configuration, when manufacturing the main shaft 8 having the structure in which the planetary gears 42 are respectively arranged between the adjacent connection portions 8D at the portion sandwiched between the first flange portion 8B and the second flange portion 8C, the time required for manufacturing can be shortened.

[0191] In the present embodiment, the flange portion 8L may be formed such that a portion facing the opening surrounded by the first flange portion 8B, the second flange portion 8C, and the plurality of connection portions 8D is a non-cut portion 8K.

[0192] According to the above configuration, the opening of the slit portion 8I can be formed by the non-cut portion 8K, and therefore, it is not necessary to perform cutting work when forming the opening.

[0193] In the present embodiment, the manufacturing method of the spindle 8 is a manufacturing method of the spindle 8 for use in an electric tool, the spindle 8 comprising: a flange portion 8L, which has an insertion hole 8H for inserting a pinion 41 in the axial direction, and has a slit portion 8I for mounting a planetary gear 42 on at least the side; and a spindle shaft portion 8A, which extends forward from the flange portion 8L, wherein the manufacturing method may include the following steps: a step of forming an iron core 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 configuring a forging die 80 having a slit corresponding portion 82 corresponding to the slit portion 8I relative to the flange corresponding portion 72 of the iron core 70; and a step of forging the flange corresponding portion 72 by forging the rear end portion 72E of the flange corresponding portion 72 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.

[0194] According to the above configuration, in a state where the forging die 80 having the slit corresponding portion 82 corresponding to the slit portion 8I is disposed relative to the flange corresponding portion 72 of the core 70, the slit portion 8I is formed by forging by striking the rear end portion 72E of the flange corresponding portion 72 in the axial direction and plastically deforming the flange corresponding portion 72 along the slit corresponding portion 82 of the forging die 80. Therefore, the slit portion 8I can be efficiently formed by forging, and thus the time required for manufacturing the spindle 8 can be shortened.

[0195] In this embodiment, the following step may be further included: the flange portion 8L of the main shaft 8 has an insertion hole 8H for inserting the pinion 41 in the axial direction, and after the flange corresponding portion 72 is plastically deformed, the flange corresponding portion 72 is cut to form the insertion hole 8H.

[0196] According to the above configuration, after the slit portion 8I is formed by forging, the insertion hole 8H is formed by cutting. Therefore, the time required for manufacturing the main shaft 8 can be shortened compared to the case where both the slit portion 8I and the insertion hole 8H are formed by cutting.

[0197] In this embodiment, the core 70 can be formed by forging when the temperature of the material is above -20°C and below 40°C, above 300°C and below 850°C, or above 1000°C and below 1250°C, and the main shaft 8 can be formed by forging when the temperature of the formed core 70 is above -20°C and below 40°C.

[0198] According to the above configuration, the core 70 can be appropriately manufactured, and the main shaft 8 can be appropriately manufactured using the appropriately manufactured core 70 .

[0199] In the present embodiment, the main shaft 8 can be formed so that the surface hardness reaches 300 HV or more by heat treatment after forging.

[0200] According to the above configuration, since the surface hardness reaches 300 HV or more by heat treatment after forging, the strength of the main shaft 8 can be ensured.

[0201] In the above-described embodiment, the power source of the impact tool 1 may not be the battery pack 25 but may be a commercial power source (AC power source).

[0202] In the above embodiment, the electric tool is an impact tool 1, and the impact tool 1 is an impact screwdriver. The impact tool 1 may be an impact wrench. In addition, the electric tool may be a screwdriver drill, a polisher, a pin breaker, or a hammer drill.

Claims

1. An impact tool, wherein: The impact tool has: 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 main shaft, comprising a flange portion and a shaft portion extending from the flange portion toward the front in the axial direction, wherein the flange portion has a hole in the axial direction for inserting the sun gear and has a slit portion on at least a side surface for mounting the planetary gear, and the flange portion is formed by forging; a hammer held on the spindle; an anvil, which is struck in a rotational direction by the hammer; A hammer housing that accommodates the hammer and holds the anvil rotatably; a front end tool holding portion formed on the anvil; as well as A coil spring urges the hammer toward the anvil side.

2. The impact tool according to claim 1, wherein: The flange portion has a cut surface on at least a portion of a surface.

3. The impact tool according to claim 1, wherein: The impact tool further comprises: a ball disposed between the spindle and the hammer, The main shaft has, in the shaft portion, a main shaft groove in which at least a part of the balls are arranged.

4. The impact tool according to claim 1, wherein: The main shaft is formed of iron containing 0.13% to 1.00% of carbon and 0.90% or more of chromium.

5. The impact tool according to claim 1, wherein: The main axis is formed at the flange portion from the radial center toward the outer side based on a forging flow line of forging.

6. The impact tool according to claim 1, wherein: The main shaft has: a first flange connected to the shaft portion; a second flange disposed behind the first flange and opposite to the first flange; as well as A connecting portion connects the first flange and the second flange in the axial direction.

7. The impact tool according to claim 6, wherein: The connecting portion is arranged in a plurality in the circumferential direction. The planetary gears are respectively arranged between the adjacent connection portions at a portion sandwiched between the first flange and the second flange.

8. The impact tool according to claim 6 or claim 7, wherein: A portion of the main shaft facing the opening surrounded by the first flange, the second flange, and the plurality of connecting portions is a non-cutting portion.

9. A spindle used in an electric tool, wherein: The spindle has: 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 mounting the planetary gear; and a shaft portion extending forward from the flange portion, The flange portion is in a state formed by forging.

10. The spindle according to claim 9, wherein: The flange portion has a cut surface on at least a portion of a surface.

11. The spindle according to claim 9, wherein: The shaft portion has a main shaft groove in which at least a part of the balls are arranged.

12. The spindle according to claim 9, wherein: The main shaft is formed of iron containing 0.13% to 1.00% of carbon and 0.90% or more of chromium.

13. The spindle according to claim 9, wherein: The flange portion is formed from the radial center toward the outer side based on a forging flow line of forging.

14. The spindle according to claim 9, wherein: The flange portion has: a first flange connected to the shaft portion; a second flange disposed behind the first flange and opposite to the first flange; as well as A connecting portion connects the first flange and the second flange in the axial direction.

15. The spindle according to claim 14, wherein: The connecting portion is arranged in a plurality in the circumferential direction. The planetary gears are respectively arranged between the adjacent connection portions at a portion sandwiched between the first flange and the second flange.

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

17. A method for manufacturing a spindle for an electric tool, the spindle comprising: a flange portion having a hole for inserting a sun gear in the axial direction and having a slit portion for mounting a planetary gear on at least a side surface; and a shaft portion extending forward from the flange portion, wherein: The manufacturing method of the main shaft comprises the following steps: a step of forming an iron core having a flange corresponding portion and a shaft corresponding portion corresponding to the flange portion and the shaft portion, respectively; a step of disposing a die having a slit corresponding portion corresponding to the slit portion, with respect to the flange corresponding portion of the core; as well as The step of forging the flange corresponding portion by plastically deforming the flange corresponding portion along the slit corresponding portion of the die by hammering the rear end portion of the flange corresponding portion in the axial direction in a state where the die is arranged, thereby forming the slit portion.

18. The method for manufacturing a main shaft according to claim 17, wherein: The flange portion of the main shaft has, in the axial direction, a hole for inserting a sun gear, The method further includes the step of forming the hole by cutting the flange corresponding portion after plastically deforming the flange corresponding portion.

19. The method for manufacturing a main shaft according to claim 17, wherein: The core is formed by forging in a state where the temperature of the material is -20°C to 40°C, 300°C to 850°C, or 1000°C to 1250°C. The main shaft is formed by forging in a state where the temperature of the core to be formed is not less than -20°C and not more than 40°C.

20. The method for manufacturing a main shaft according to claim 17, wherein: The main shaft is formed by heat treatment after forging so that the surface hardness reaches 300 HV or more.

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