PERCUSSION TOOL, SPINDLE AND SPINDLE MANUFACTURING PROCESS

Abstract

problem Providing a striking tool, a spindle and a method for manufacturing the spindle, whereby the time required for manufacturing can be reduced. Solution A striking tool comprises a motor, a sun gear rotated by the motor, at least three planet gears meshing with the sun gear, and an internal gear meshing with the planet gears. A spindle has a flanged section with an axial hole for inserting the sun gear and slotted sections in at least one side surface for mounting the planet gears, and a shaft extending axially forward from the flanged section. The flanged section is formed by forging. A hammer is held on the spindle, and an anvil is struck by the hammer in a rotational direction. A hammer housing receives the hammer and holds the anvil rotatably; a tool accessory holder is formed on the anvil, and a coil spring biases the hammer toward the anvil.

Description

TECHNICAL FIELD

[0001] The techniques disclosed in the present specification relate to an impact tool, a spindle, and a method of manufacturing the spindle. STATE OF THE ART

[0002] An impact tool relating to the present teachings is disclosed in JP 2021 - 037 561 B2. SHORT SUMMARY

[0003] It is a non-limiting object of the present teachings to disclose techniques for reducing the time required to manufacture the spindle for a power tool.

[0004] The above object is achieved by an impact tool according to claim 1, or a spindle for a power tool according to claim 9 or a method for producing a spindle according to claim 17.

[0005] In one non-limiting aspect of the present teachings, an impact tool may preferably 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 spindle having a flange portion—having a hole in an axial direction for inserting the sun gear and slot portions in at least one side surface thereof for mounting the planetary gears—and a shank portion extending forward from the flange portion in an axial direction, in which at least a portion of the flange portion has been formed by forging, a hammer held on the spindle, an anvil struck by the hammer in a rotational direction, a hammer case accommodating the hammer and holding the anvil in a rotatable manner, a tool accessory holding part,which is provided on the anvil, and have a coil spring that biases the hammer towards the side of the anvil.

[0006] By using the spindle forging techniques disclosed in the present specification, an impact tool, a spindle, and a method for manufacturing a spindle are provided in which the time required for manufacturing can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a front perspective view showing an impact tool according to an embodiment of the present teachings. Fig. 2 is a side view showing an upper portion of the impact tool according to the embodiment. Fig. 3 is a longitudinal cross-sectional view showing the upper portion of the impact tool according to the embodiment. Fig. 4 is a transverse cross-sectional view showing the upper portion of the impact tool according to the embodiment. Fig. 5 is an exploded perspective view showing a spindle and related parts of the impact tool according to the embodiment. Fig. 6 is a bottom view showing the spindle according to the embodiment. Fig. 7A schematically shows an example of granulate flows in a solidified region of the spindle according to a first forging variant of the embodiment. Fig. 7B schematically shows another example of granulate flows in the fixed region of the spindle according to a second forging variant of the embodiment. Fig. 8 is a side view of the spindle according to the embodiment. Fig. 9 is a flowchart showing an example of a method for manufacturing the spindle according to the embodiment. Fig. 10 is an example of a blank (semi-finished product) according to the embodiment. Fig. 11 shows an example of a forging die according to the embodiment. Fig. 12 shows an example of a die arranging step according to the embodiment. Fig. 13A shows an example of a first type of forging step according to the embodiment. Fig. 13B shows an example of a second type of forging step according to the embodiment. Fig. 14A shows an example of a first type of cutting step according to the embodiment. Fig. 14B shows an example of a second type of cutting step according to the embodiment. Fig. 14C schematically shows an example of granule flows in the fixed portion of the spindle according to the embodiment. Fig. 14D shows another example of granule flows in the fixed portion of the spindle according to the second forging variant of the embodiment. Fig. 15A shows an example of a forging step according to the first forging variant of the embodiment. Fig. 15B shows another example of a forging step according to the second forging variant of the embodiment. Fig. 16A shows an example of a cutting step according to the embodiment. Fig. 16B shows another example of a cutting step according to the embodiment. Fig. 16C schematically shows another example of granulate flows in the fixed region of the spindle according to the second forging variant of the embodiment. Fig. 16D schematically shows another example of granulate flows in the fixed region of the spindle according to the second forging variant of the embodiment. DETAILED DESCRIPTION

[0007] As described above, an impact tool according to one aspect of the present teachings preferably comprises 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 spindle having a flange portion—which has a hole in an axial direction for inserting the sun gear and slot portions on at least one side surface thereof for mounting the planetary gears—and a shaft portion extending forward from the flange portion in the axial direction, in which at least a portion of the flange portion is formed by forging, a hammer held on the spindle, an anvil struck by the hammer in a rotational direction, a hammer case that accommodates the hammer and holds the anvil in a rotatable manner, a tool accessory holding part,which is provided on the anvil, and a coil spring which biases the hammer towards the side of the anvil.

[0008] In the configuration described above, it is possible to reduce the time required to manufacture the impact tool by using the spindle which has been formed (shaped) by forging.

[0009] In one or more embodiments, the flange portion may have a cut surface (cut surface) on at least a portion of a surface.

[0010] In the configuration described above, the accuracy of the external shape of the spindle can be improved, if necessary and appropriate, by cutting the surface of the flange portion formed (formed) by forging.

[0011] In one or more embodiments, the impact tool may further comprise a ball disposed between the spindle and the hammer, and the spindle may comprise a spindle groove in the shank region in which at least a portion of the ball is disposed.

[0012] In the configuration described above, the time required for manufacturing can be reduced if the spindle is manufactured having, in the shaft portion, the spindle groove in which at least a part of the ball is arranged.

[0013] In one or more embodiments, the spindle can be manufactured using a steel containing 0.13 mass percent or more and 1.00 mass percent or less of carbon and 0.90 mass percent or more of chromium. When the forging steps described below are performed under cold working conditions, a cold working steel is preferred. On the other hand, when the blank is produced by forging under warm or hot working conditions, a steel suitable for both cold working and warm or hot working is preferred.

[0014] In the configuration described above, it is possible to cause plastic deformation of the spindle, where appropriate, by forging, which can ensure the strength after deformation.

[0015] In one or more embodiments, the granulate flows (material flows) (which may be referred to as fiber flows or metal flows) may be formed in the flange portion of the spindle by forging such that the granulate flows are directed (run) outward from the center of the radial direction at least in one or more regions of the flange portion, e.g. at least in the first and second flange portions of the spindle.

[0016] In the configuration described above, since at least some of the granule flows in the flange portion of the spindle are formed by forging to extend outward from the center of the radial direction, appropriate strength of the spindle can be ensured.

[0017] In one or more embodiments, the spindle may include a first flange connected to the shaft portion, a second flange disposed opposite the first flange and rearward of the first flange, and a connecting portion (coupling portion) that connects (couples) the first flange and the second flange to each other in the axial direction. The first flange and the second flange preferably extend parallel to each other in the radial direction.

[0018] In the configuration described above, the time required for manufacturing can be reduced if a spindle is manufactured (specifically, the flange portion thereof) configured to have the first flange, the second flange, and the connecting portion.

[0019] In one or more embodiments, a plurality of connecting portions are arranged in a circumferential direction, and each of the planetary gears may be arranged between mutually adjacent connecting portions at a location sandwiched between the first flange and the second flange.

[0020] In the configuration described above, the time required for manufacturing can be reduced if a spindle is manufactured (specifically, the flange portion thereof) configured such that each of the planetary gears is respectively arranged between mutually adjacent connecting portions at a position sandwiched between the first flange and the second flange.

[0021] In one or more embodiments, a region of the spindle that faces (directs toward) an opening surrounded by the first flange, the second flange, and the plurality of connecting portions may be a non-cutting portion. In other words, such a portion is preferably formed (shaped) only by forging, without performing any cutting process thereon.

[0022] In the configuration described above, since each of the openings of the slit portions can be configured (formed) by corresponding non-cut portions, cutting for forming these openings need not be performed.

[0023] In one or more embodiments, the spindle may be a spindle used in a power tool (preferably an impact tool), and may include a flange portion having a hole in an axial direction for inserting a sun gear and a slot portion in at least one side surface for mounting a planetary gear, and a shank portion extending forward from the flange portion, and at least a portion of the flange portion may be formed (formed) by forging.

[0024] With the configuration described above, it is possible to reduce the time required for manufacturing the spindle (in particular, the flange portion thereof) because at least a part (portion) of the flange portion is formed (formed) by forging.

[0025] In one or more embodiments, the flange portion may include a cutting surface on at least a portion of a surface.

[0026] In the configuration described above, the accuracy (precision) of the outer shape of the spindle can be improved, if necessary and appropriate, by cutting at least a portion of the surface of the flange portion formed (formed) by forging.

[0027] In one or more embodiments, the shaft portion may have a spindle groove in which at least a portion of the ball is arranged.

[0028] In the configuration described above, the time required for manufacturing can be reduced if a spindle is manufactured having, in the shaft portion, the spindle groove in which at least a part of the ball is arranged.

[0029] As described above, the spindle may be formed of steel containing 0.13% or more and 1.00% or less of carbon and 0.90% or more of chromium.

[0030] With the configuration described above, it is possible to achieve an appropriate degree of plastic deformation of the spindle by forging, and thus it becomes possible to ensure sufficient strength after deformation thereof.

[0031] In one or more embodiments, at least a portion of the granulate streams in the flange region may be formed by forging such that the granulate streams extend radially outward from the center of the spindle in the radial direction (i.e., in the direction radially outward from the rotational axis of the spindle).

[0032] In the configuration described above, since at least a part of the granule flows in the flange portion is formed by forging such that the granule flows extend outward from the center of the radial direction, appropriate strength of the spindle can be ensured.

[0033] In one or more embodiments, the flange portion may include a first flange connected to the shaft portion, a second flange disposed opposite to and rearward of the first flange, and at least one connecting portion (coupling portion) connecting (coupling) the first flange and the second flange to each other in the axial direction.

[0034] With the configuration described above, the time required for manufacturing can be reduced when manufacturing a spindle (specifically, the flange portion thereof) configured to have the first flange, the second flange, and at least one connecting portion.

[0035] In one or more embodiments, a plurality of connecting portions may be arranged in a circumferential direction, and each of the planetary gears may be arranged between respective mutually adjacent connecting portions at a location sandwiched (provided) between the first flange and the second flange.

[0036] In the configuration described above, the time required for manufacturing can be reduced if a spindle is manufactured (specifically, the flange portion thereof) configured such that each of the planetary gears is respectively arranged between mutually adjacent connecting portions at a position sandwiched between the first flange and the second flange.

[0037] As described above, a portion of the flange portion opposite to an opening surrounded by the first flange, the second flange, and the plurality of connecting portions may be a non-intersecting portion.

[0038] In the configuration described above, since each of the openings of the slit portions can be configured (formed) by corresponding non-cut portions, cutting for forming these openings need not be performed.

[0039] In one or more embodiments, a method of manufacturing a spindle having a flange portion having a hole in an axial direction for inserting a sun gear and a slot portion on at least one side surface thereof for mounting a planetary gear, and a shank portion extending forward from the flange portion, the spindle being used in a power tool, may comprise: (i) forming (providing) a blank (intermediate product, semi-finished product) having a flange corresponding portion and a shank corresponding portion corresponding to the flange portion and the shank portion, respectively;corresponding to the shank portion, (ii) arranging (arranging, providing) with respect to the flange corresponding portion of the blank, a die in which at least one slot corresponding part corresponding to the at least one slot portion is formed (defined), and (iii) forming a slot portion by forging, in which, in a state in which the die is arranged, a rear end portion of the flange corresponding portion is struck in the axial direction to cause plastic deformation of the flange corresponding portion along the slot corresponding part of the die. The term "slug" used herein is intended to mean "a piece of metal roughly formed for subsequent machining" and is intended to be synonymous with terms such as "intermediate product" or "semi-finished product / semi-finished product".

[0040] In the above-described configuration, in the state where the die—in which the slot corresponding part(s) corresponding to the slot region(s) is (are) formed—is arranged with respect to the flange corresponding portion of the blank, the slot region(s) is (are) formed by forging, in which the rear end portion of the flange corresponding portion is (are) struck in the axial direction to cause plastic deformation of the flange corresponding portion along the slot corresponding part(s) of the die. Accordingly, the time required for manufacturing the spindle can be reduced because the slot region(s) can be efficiently formed by forging.

[0041] In one or more embodiments, the flange portion of the spindle may include a hole in the axial direction for inserting a sun gear, and the manufacturing method may further include a step of forming the hole by cutting the flange corresponding portion after plastically deforming the flange corresponding portion.

[0042] In the configuration described above, since the hole is formed by cutting after forming the slit portion(s) by forging, the time required for manufacturing the spindle can be reduced compared to an embodiment in which both the slit portion and the hole are formed by cutting.

[0043] In one or more embodiments, the blank may be formed by forging in which the material temperature is -20°C or higher and 40°C or lower (cold working), 300°C or higher and 800°C or lower (hot working), or 1000°C or higher and 1250°C or lower (hot working), and the spindle may be formed by further forging the blank in the state where the blank temperature is -20°C or higher and 40°C or lower (cold working). Note that when forging the blank, the blank temperature may be any temperature as long as it is within the range of -20°C or higher and 1250°C or lower.

[0044] In the configuration described above, the blank can be suitably manufactured, and the spindle can be suitably manufactured using the suitably manufactured blank.

[0045] In one or more embodiments, the spindle may be further treated (preferably heat treated) after being formed by forging so that its surface hardness becomes 300 HV or greater.

[0046] With the configuration described above, it is possible to ensure sufficient strength of the spindle because the surface hardness of the spindle after forging becomes 300 HV or greater through heat treatment. Note that any process can be performed as the heat treatment as long as it is a process that causes a material property of the spindle (specifically, the surface hardness) to change (increase). Examples of non-limiting heat treatments that can be performed on the spindle include quenching, such as immersion quenching, carburizing and quenching, carbonitriding and quenching, and induction hardening or age hardening, among others.

[0047] Embodiments of the present disclosure will be described below with reference to the drawings, but the present disclosure is not limited to these embodiments. Structural elements of the embodiments described below can be combined as appropriate. Furthermore, there are cases where some structural elements are not used.

[0048] In the embodiments, positional relationships among the parts are described using the terms left, right, front, back, top, and bottom. These terms indicate a relative position or direction, with the center of an impact tool as the reference.

[0049] The impact tool comprises a motor. In the embodiments, the direction parallel to the rotational axis AX of the motor is referred to as the axial direction, where appropriate, and the direction extending around the rotational axis AX is referred to as the circumferential direction or the rotational direction, where appropriate, and the radial direction of the rotational axis AX is referred to as the radial direction, where appropriate.

[0050] In the embodiments, the rotation axis AX extends in a front-to-back direction. The axial direction and the front-to-back direction coincide. One side in the axial direction is forward, and the other side in the axial direction is rearward. Furthermore, in the radial direction, a position close to or a direction approaching the rotation axis AX is referred to as radially inward, where appropriate, and a position away from or a direction away from the rotation axis AX is referred to as radially outward, where appropriate.

[0051] Fig. 1 is a perspective view seen from the front showing an impact tool 1 according to the embodiment. Fig. 2 is a side view showing an upper portion of the impact tool 1 according to the embodiment. Fig. 3 is a longitudinal cross-sectional view showing the upper portion of the impact tool 1 according to the embodiment. Fig. 4 is a transverse cross-sectional view showing the upper portion of the impact tool 1 according to the embodiment. Fig. 5 is a right side view showing a spindle and related parts of the impact tool 1 according to the embodiment.

[0052] In the embodiment, an impact tool 1 is described as an example of an impact tool according to the present teachings. In the embodiment, the impact tool is an impact wrench, which is a type of screw tightening tool according to the present teachings. 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 shock absorber 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 mounting part 13, a trigger lever 14, a forward-reverse switching lever 15, an interface panel 16, a quick mode switching button 17, and a light assembly 18.

[0053] The housing 2 is made of a synthetic resin (polymer). In the present embodiment, the housing 2 is made of nylon (polyamide). The housing 2 includes a left housing 2L and a right housing 2R located to the right of the left housing 2L. The left housing 2L and the right housing 2R are fixed to each other by a plurality of screws 2S. Thus, the housing 2 is formed from a pair of housing halves.

[0054] The housing 2 has a motor housing part 21, a handle part 22 and a battery holding part 23.

[0055] The motor housing part 21 accommodates the motor 6. The motor housing part 21 includes at least a portion of the hammer housing 4. The motor housing part 21 has a tubular shape.

[0056] The handle portion 22 is gripped by the user. The handle portion 22 extends downward from the motor housing portion 21. The trigger lever 14 is provided at an upper portion of the handle portion 22.

[0057] The battery holding part 23 holds a battery pack 25 via the battery mounting part 13. The battery holding part 23 is connected to a lower end portion of the handle part 22. In both the front-to-back direction and the left-to-right direction, the dimensions of the outer shape of the battery holding part 23 are larger than the dimensions of the outer shape of the handle part 22.

[0058] The rear cover 3 is arranged to cover an opening in a rear end portion of the motor housing part 21. The rear cover 3 is arranged at the rear of the motor housing part 21. The rear cover 3 accommodates at least a part of the fan impeller 12. The fan impeller 12 is arranged inside the rear cover 3. The rear cover 3 holds a rear rotor bearing 37. The rear cover 3 is formed of a synthetic resin (polymer), such as nylon. The rear cover 3 is fixed to the rear end portion of the motor housing part 21 by two screws 3S.

[0059] The motor housing part 21 has air intake openings 19. The rear cover 3 has air discharge openings 20. Air outside the housing 2 flows into the interior of the housing 2 via the air intake openings 19. Air in the interior of the housing 2 flows out to the outside of the housing 2 via the air discharge openings 20.

[0060] The hammer housing 4 houses at least a part of the speed reduction mechanism 7 and houses the spindle 8, the impact mechanism 9, and at least a part 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 has a tubular shape. The hammer housing 4 is connected to a front portion of the motor housing part 21. The bearing box 24 is fixed to a rear end portion of the hammer housing 4. The bearing box 24 (specifically, a front portion 24B thereof) houses (holds) at least a part of the speed reduction mechanism 7. The bearing box 24 holds a front-side rotor bearing 38 and a 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.An intermediate portion 24C of the bearing box 24 extends between a base of the bearing box 24 and the front portion 24B thereof.

[0061] The hammer housing 4 is sandwiched between the left housing 2L and the right housing 2R. The rear portion of the hammer housing 4 is received in the motor housing part 21. The hammer housing 4 is connected to a front portion of the motor housing part 21. The bearing box 24 is fixed to both the motor housing part 21 and the hammer housing 4.

[0062] The hammer housing cover 51 protects the hammer housing 4. The hammer housing cover 51 blocks contact between the hammer housing 4 and objects around the hammer housing 4. The hammer housing cover 51 is arranged to cover the outer peripheral surface of a large pipe area 4A.

[0063] The shock absorber 52 protects the hammer housing 4. The shock absorber 52 blocks contact between the hammer housing 4 and objects around the hammer housing 4. The shock absorber 52 dampens the impact when it comes into contact with an object. The shock absorber 52 is arranged around a small tube section 4B.

[0064] The motor 6 is the driving power source of the impact tool 1. The motor 6 is an inner-rotor type brushless motor. The motor 6 includes a stator 26 and a rotor 27. The stator 26 is supported by the motor housing part 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 around the rotation axis AX, which extends in the front-to-back direction.

[0065] The stator 26 has a stator core 28, a rear insulating piece 29, a front insulating piece 30 and coils 31.

[0066] The stator core 28 includes (is formed from) a plurality of laminated steel discs. Each of the steel discs is a disc made of metal, with iron as the main component. The stator core 28 has a tubular shape. The stator core 28 is arranged further radially outward than the rotor 27. The stator core 28 has teeth that respectively support the coils 31.

[0067] The back insulating piece 29 and the front insulating piece 30 are each electrically insulating members made of a synthetic resin (polymer). The back insulating piece 29 and the front insulating piece 30 each electrically insulate the stator core 28 and the coils 31 from each other. The back insulating piece 29 is fixed to a rear portion of the stator core 28. The front insulating piece 30 is fixed to a front portion of the stator core 28. The back insulating piece 29 is arranged to cover a front portion of the surface of each of the teeth. The front insulating piece 30 is arranged to cover a rear portion of the surface of each of the teeth.

[0068] The coils 31 are mounted (wound) on the stator core 28 via the rear insulating piece 29 and the front insulating piece 30. A plurality of coils 31 are provided. The coils 31 are respectively arranged around the teeth of the stator core 28 via the rear insulating piece 29 and the front insulating piece 30. The coils 31 and the stator core 28 are electrically insulated from each other by the front insulating piece 30 and the rear insulating piece 29. The coils 31 are electrically connected to a power source (e.g., the battery pack) via fuse terminals 36.

[0069] The rotor 27 rotates about the rotation axis AX. The rotor 27 has a rotor core 32, a rotor shaft 33, at least one rotor magnet 34A, and at least one sensor magnet 34B.

[0070] The rotor core 32 and the rotor shaft 33 are each made of steel. In the embodiment, the rotor core 32 and the rotor shaft 33 are a single body. 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.

[0071] The rotor magnet 34A is fixed to the rotor core 32. In this embodiment, the rotor magnet 34A is arranged around the rotor core 32. The sensor magnet 34B is fixed to the rotor core 32. In this embodiment, the sensor magnet 34B is arranged on the front end surface of the rotor core 32.

[0072] A sensor board 35 is mounted on the front insulating piece 30. The sensor board 35 is fixed to the front insulating piece 30 by a screw 30S. The sensor board 35 includes a circuit board having a circular shape and at least one rotation detection device mounted on the circuit board. At least a portion of the sensor board 35 faces a front end surface of the sensor magnet 34B. The rotation detection device detects the position of the rotor 27 in the rotation direction by detecting the position of the sensor magnet 34B.

[0073] A rear end portion of the rotor shaft 33 is rotatably supported by the rear rotor bearing 37. A front end portion of the rotor shaft 33 is rotatably supported by the 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.

[0074] The front end portion of the rotor shaft 33 is arranged in an interior space of the hammer housing 4 via an opening provided in a rear annular portion 24A of the bearing box 24.

[0075] A drive gear (sun gear) 41 is formed at the front end portion of the rotor shaft 33. The drive gear 41 is coupled to an input portion of the speed reduction mechanism 7. Specifically, the rotor shaft 33 is coupled to the speed reduction mechanism 7 via the drive gear 41.

[0076] The speed reduction mechanism 7 couples the rotor shaft 33 and the spindle 8. 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 spindle 8. The speed reduction mechanism 7 causes the spindle 8 to rotate at a speed lower than the speed of the rotor shaft 33, but with increased torque. The speed reduction mechanism 7 is arranged further forward than the stator 26. The speed reduction mechanism 7 comprises a planetary gear mechanism.

[0077] The planetary gear mechanism of the speed reduction mechanism 7 includes a plurality of planetary gears 42 arranged around the drive gear 41, and an internal gear 43 arranged around the plurality of planetary gears 42. The drive gear 41, the planetary gears 42, and the internal gear 43 are each housed in the hammer housing 4. Each of the planetary gears 42 meshes with the drive gear 41. The planetary gears 42 are each rotatably supported by the spindle 8 via pins 42P. The spindle 8 is rotated by the planetary gears 42. The internal gear 43 has internal teeth that mesh with the planetary gears 42.

[0078] The internal gear 43 is fixed to the large tube portion 4A of the hammer housing 4. The internal gear 43 is always non-rotatable relative to the hammer housing 4.

[0079] When the rotor shaft 33 rotates due to the driving of the motor 6, the drive gear 41 rotates, and the planetary gears 42 revolve around the drive gear 41. The planetary gears 42 revolve while meshing with the internal teeth of the internal gear 43. Due to the revolution of the planetary gears 42, the spindle 8, which is connected to the planetary gears 42 via the pins 42P, rotates at a speed lower than the speed of the rotor shaft 33.

[0080] Fig. 5 is an exploded perspective view showing the spindle 8 and related parts of the impact tool 1 according to the embodiment. Fig. 6 is a bottom view showing the spindle 8 according to the embodiment. Fig. 7A and Fig. 7B each schematically shows the granulate flows in the solidified region of the spindle 8 according to two different variants of the embodiment. Fig. Fig. 8 is a side view of the spindle 8 according to the embodiment.

[0081] The spindle 8 rotates about the rotation axis AX in response to the excitation of the motor 6. Specifically, the spindle 8 rotates by the rotational force of the rotor 27 transmitted thereto via the speed reduction mechanism 7. The spindle 8 transmits the rotational force of the motor 6 to the anvil 10 via balls 48 and a hammer 47. At least a portion of the spindle 8 is arranged further forward than the motor 6. The spindle 8 is arranged further forward than the stator 26. At least a portion of the spindle 8 is arranged further forward than the rotor 27. At least a portion of the spindle 8 is arranged further forward than the speed reduction mechanism 7. At least a portion of the spindle 8 is arranged further rearward than the anvil 10.

[0082] The spindle 8 has a spindle shaft area 8A and a flange area 8L.

[0083] The spindle shaft portion 8A has a rod shape that is elongated in the front-to-back direction. The central axis of the spindle shaft portion 8A and the rotation axis AX coincide (are collinear). The spindle shaft portion 8A has a spindle protrusion portion 8F. The spindle protrusion portion 8F protrudes forward from a front end portion of the spindle shaft portion 8A.

[0084] The flange portion 8L includes a first flange portion 8B, a second flange portion 8C, and connecting portions 8D. The first flange portion 8B extends radially outward from an outer peripheral surface of the spindle shaft portion 8A at a rear end portion thereof. The second flange portion 8C is located further rearward than the first flange portion 8B. The second flange portion 8C has an annular shape. The second flange portion 8C has an insertion hole 8H in the axial direction for inserting the drive gear 41. The insertion hole 8H is located in the second flange portion 8C at the center thereof in the up-down direction and in the left-right direction.

[0085] Slot portions (groove portions, recess portions, gap portions) 8I are formed between the first flange portion 8B and the second flange portion 8C. The slot portions 8I are spaces for mounting the planetary gears 42 therein, as shown in Fig. 5. At least some of the slot regions 8I are open in (on, along) a side surface of the flange region 8L.

[0086] The connecting portions 8D connect portions of the first flange portion 8B and portions of the second flange portion 8C to each other. Each of the connecting portions 8D is arranged on a side surface of the flange portion 8L. In the present embodiment, the connecting portions 8D are equally spaced in the circumferential direction. The connecting portions 8D partition the slot portions 8I at circumferential edge portions of the first flange portion 8B and the second flange portion 8C. The front end portions of the pins 42P are supported by the first flange portion 8B. The rear end portions of the pins 42P are supported by the second flange portion 8C. Portions of the planetary gears 42 are arranged between the first flange portion 8B and the second flange portion 8C, as shown in Fig. 5. The planetary gears 42 are each rotatably supported by the first flange portion 8B and the second flange portion 8C via the pins 42P. Each of the planetary gears 42 is arranged between mutually adjacent connecting portions 8D in the circumferential direction at a position sandwiched between the first flange portion 8B and the second flange portion 8C.

[0087] The spindle bearing 44 (see Fig. 4, etc.) is disposed inside a cylindrical portion 8E of the spindle 8, and the cylindrical portion 8E protrudes rearward from a rear surface of the second flange portion 8C. The spindle bearing 44 rotatably supports the cylindrical portion 8E of the spindle 8. The spindle bearing 44 is held in the bearing box 24.

[0088] In the present embodiment, at least a portion of the flange portion 8L of the spindle 8 is formed (formed) by forging. As shown in Fig. 7A and Fig. As shown in Figure 7B, viewed in cross section, the granulate streams 8T in the spindle 8 are formed by forging. Fig. Figure 7A shows the granulate flows in an embodiment in which forging was carried out by an upsetting process, and Fig. Figure 7B shows the granule streams in an embodiment in which forging was performed by a reverse extrusion process, as described in detail later. Fig. 7A and Fig. 7B, the granule streams 8T are formed and extend outward from the center of the radial direction in the first flange portion 8B, in the second flange portion 8C, and in the cylindrical portion 8E of the flange portion 8L. It is noted that in the example shown in Fig. 7A, the granulate streams 8T are formed along the radial direction in the cylindrical region 8E. In addition, in Fig. 7A, the granule streams 8T formed in the cylindrical portion 8E are formed such that they are separated (detached) from other portions, such as the second flange portion 8C, as will be described later. On the other hand, in the example shown in Fig. 7B, the granule streams 8T are formed to be continuous from the cylindrical portion 8E to the second flange portion 8C. Thus, the shapes of the granule streams 8T formed in the flange portion 8L differ between an embodiment in which forging is performed by the upsetting method and an embodiment in which forging is performed by the backward extrusion method.

[0089] Regions of the spindle 8 that are opposite to the openings 8P surrounded (defined) by the first flange portion 8B, the second flange portion 8C, and the plurality of connecting portions 8D are non-cutting portions 8K. The non-cutting portions 8K are portions where cutting is not performed with respect to the surfaces formed by forging. Cutting is performed on portions other than the non-cutting portions 8K of the spindle 8. Thus, since the openings of the slit portions 8I can be configured (formed) by the non-cutting portions 8K, respectively, cutting for forming these openings 8P need not be performed.

[0090] The spindle 8 is formed using a steel containing 0.13% or more and 1.00% or less of carbon and 0.90% or more of chromium. It should be noted that the spindle 8 can be formed using steel containing at least carbon, chromium, and molybdenum. Due to such a composition of the spindle 8 (blank 70), it is possible to sufficiently plastically deform the spindle by forging, and furthermore, it is possible to ensure sufficient strength after deformation thereof due to work hardening resulting from cold working the spindle 8 to form the second flange portion 8C. Preferably, the first flange portion 8B is formed by forging a precursor (blank) to form the blank 70, thereby achieving work hardening in the first flange portion 8B before forging the second flange portion 8C.

[0091] 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 spindle 8. The striking mechanism 9 strikes the anvil 10 in a rotational direction using the rotational force of the spindle 8, which is rotated by the motor 6. The striking mechanism 9 includes the hammer 47, the balls 48, a coil spring 49, and a washer 50. The striking mechanism 9, which includes the hammer 47, the balls 48, the coil spring 49, and the washer 50, is housed in the large tube portion 4A of the hammer housing 4.

[0092] The hammer 47 is arranged further forward than the speed reduction mechanism 7. The hammer 47 is arranged around the spindle 8. The hammer 47 is arranged around the spindle shaft portion 8A. The hammer 47 is held on the spindle shaft portion 8A. The balls 48 are arranged between the spindle and the hammer 47.

[0093] The hammer 47 is rotated using the rotational power output by the motor 6, as described in detail later. The rotational power of the motor 6 is transmitted to the hammer 47 via the speed reduction mechanism 7 and the spindle 8. The hammer 47 is rotatable together with the spindle 8 using the rotational power of the spindle 8, which is rotated by the motor 6. The rotational axis of the hammer 47, the rotational axis of the spindle 8, and the rotational axis AX of the motor 6 coincide. The hammer 47 rotates around the rotational axis AX.

[0094] The washer 50 is disposed within a recessed portion 47E, which is partially defined by a radially outer annular portion 47B. The washer 50 is mounted on the hammer 47 via a plurality of balls 54. The balls 54 are disposed further forward than the washer 50. The balls 54 are disposed between a rear surface of a body portion 47A and a front surface of the washer 50.

[0095] The coil spring 49 is arranged around the spindle shaft portion 8A. A rear end portion of the coil spring 49 is supported by (in contact with) the first flange portion 8B. A front end portion of the coil spring 49 is arranged inside the recessed portion 47E and supported by (in contact with) the washer 50. The coil spring 49 continuously generates an elastic force that urges (biases) the hammer 47 to move forward.

[0096] The balls 48 are made of a metal such as steel. The balls 48 are arranged between the spindle shaft portion 8A and the body portion 47A. The spindle shaft portion 8A has spindle grooves 8G, in each of which at least a part of the corresponding ball 48 is arranged. The spindle grooves 8G are provided in portions of the outer peripheral surface of the spindle shaft portion 8A. The hammer 47 has hammer grooves 47G, in each of which at least a part of the corresponding ball 48 is arranged. Each of the hammer grooves 47G is provided in a portion of the body portion 47A and a portion of an inner peripheral surface of an inner tube portion 47C.

[0097] Two of the balls 48 are provided. Two of the spindle grooves 8G are provided in the outer peripheral surface of the spindle shaft portion 8A. Two of the hammer grooves 47G are provided in the body portion 47A and the inner peripheral surface of the inner tube portion 47C. One of the balls 48 is arranged between one of the spindle grooves 8G and one of the hammer grooves 47G. The other of the balls 48 is arranged between the other of the spindle grooves 8G and the other of the hammer grooves 47G. Each of the balls 48 can roll along the inner side of the corresponding spindle groove 8G and the inner side of the corresponding hammer groove 47G, respectively. The hammer 47 is movable when the balls 48 move. The spindle 8 and the hammer 47 can move relative to each other in both the axial direction and the rotational direction within a movable range defined by the spindle grooves 8G and the hammer grooves 47G.

[0098] The anvil 10 is arranged further forward than the motor 6. The anvil 10 is an output part of the impact tool 1, which is rotated by the rotational force of the rotor 27. At least a portion of the anvil 10 is arranged further forward than the spindle 8. At least a portion of the anvil 10 is arranged further forward than the hammer 47. The anvil 10 is struck in the direction of rotation by the hammer 47.

[0099] The anvil 10 includes an anvil shaft portion 10A and anvil protrusion portions 10B. The anvil shaft portion 10A has a rod shape that is elongated in the front-to-back direction. The central axis of the anvil shaft portion 10A and the rotation axis AX coincide (are collinear). The anvil protrusion portions 10B are provided at rear end portions of the anvil shaft portion 10A. The anvil protrusion portions 10B protrude radially outward from the rear end portions of the anvil shaft portion 10A. Two of the anvil protrusion portions 10B are provided.

[0100] A tool hole 10C is provided in a front end surface of the anvil 10. An anvil recess portion 10D is provided in a 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 accessory (e.g., a screwdriver bit) is inserted into the tool hole 10C. Thus, the tool accessory is mounted on (in) the anvil 10. The anvil recess portion 10D is provided to recess forward from the rear end surface of the anvil 10. The spindle protrusion portion 8F is disposed in the anvil recess portion 10D.

[0101] The anvil 10 is rotatably supported by anvil bearings 46. The rotational axis of the anvil 10, the rotational axis of the hammer 47, the rotational axis of the spindle 8, and the rotational axis AX of the motor 6 coincide (are collinear). The anvil 10 rotates about the rotational axis AX. The anvil bearings 46 are arranged around the anvil shaft portion 10A. O-rings 45 are arranged between the anvil bearings 46 and the anvil shaft portion 10A. The anvil bearings 46 are arranged inside the small tube portion 4B of the hammer housing 4. The anvil bearings 46 are held in the small tube portion 4B of the hammer housing 4, which is connected to the large tube portion 4A of the hammer housing 4 by an intermediate portion 4C. The hammer housing 4 supports the anvil 10 via the anvil bearings 46. The anvil bearings 46 rotatably support a front portion of the anvil shaft portion 10A. In the embodiment, two of the anvil bearings 46 are provided in the front-to-rear direction.

[0102] A washer 56 is provided at the front of the anvil protrusion portions 10B. The washer 56 blocks contact between the front surfaces of the anvil protrusion portions 10B and the hammer housing 4. A bearing member 57 is arranged at the rear of the anvil bearings 46. The bearing member 57 is arranged to come into contact with a rear surface of an outer ring of one of the anvil bearings 46. The bearing member 57 has a ring shape. The bearing member 57 restricts (blocks) the anvil bearings 46 from detaching rearward from the small tube portion 4B. The bearing member 57 is arranged in a groove provided in an inner peripheral surface of the small tube portion 4B.

[0103] The hammer protrusion portions 47D can come into contact with the anvil protrusion portions 10B. In the state where the hammer protrusion portions 47D and the anvil protrusion portions 10B are continuously in contact with each other, the anvil 10 rotates together with the hammer 47 and the spindle 8 due to the driving of the motor 6.

[0104] The anvil 10 can also be struck in the rotation direction by the hammer 47. For example, during a screw tightening work, when the load acting on the anvil 10 becomes large, the anvil 10 can no longer be caused to rotate solely by the load of the coil spring 49. When the anvil 10 can no longer be caused to rotate solely by the load of the coil spring 49, the rotation of the anvil 10 and the hammer 47 will temporarily stop. At this time, the spindle 8 and the hammer 47 can move relative to each other in the axial direction and in the circumferential direction by means of the balls 48. Even if the rotation of the hammer 47 temporarily stops, the spindle 8 continues to rotate due to the drive power generated by the motor 6.In the state where the rotation of the hammer 47 is temporarily stopped and the spindle 8 continues to rotate, the balls 48 move backward while being guided by the spindle grooves 8G and the hammer grooves 47G, respectively. In the state where the rotation of the hammer 47 is temporarily stopped and the spindle 8 continues to rotate, an outer peripheral surface 8S of the spindle 8 and an inner peripheral surface 47S of the hammer 47 slide relative to each other. The hammer 47 receives a force from the balls 48 and moves backward while the balls 48 move. That is, while the anvil 10 is temporarily stopped, the hammer 47 moves backward due to the rotation of the spindle 8. Due to the backward movement of the hammer 47, contact between the hammer protrusion portions 47D and the anvil protrusion portions 10B is released.

[0105] As described above, the coil spring 49 continuously generates an elastic force, which urges the hammer 47 to move forward. After moving backward, the hammer 47 moves forward due to the elastic force of the coil spring 49. As the hammer 47 moves forward, it receives a force in the rotational direction from the balls 48. That is, the hammer 47 moves forward while rotating. As the hammer 47 moves forward while rotating, the hammer protrusions 47D respectively come into contact with the anvil protrusions 10B while rotating. At this time, the anvil protrusions 10B are struck in the rotational direction by the hammer protrusions 47D of the hammer 47. The rotational power of the motor 6 and the inertial force of the hammer 47 both act on the anvil 10. Accordingly, the anvil 10 can be rotated about the rotation axis AX with a higher torque.

[0106] The tool holding mechanism 11 is arranged around a front portion of the anvil 10. The tool holding mechanism 11 holds a tool accessory inserted into the tool hole 10C of the anvil 10. The tool accessory is removable from the tool holding mechanism 11.

[0107] The fan impeller 12 is arranged further rearward than the stator 26 of the motor 6. The fan impeller 12 generates an airflow for cooling the motor 6. The fan impeller 12 is fixed to at least a portion of the rotor 27. The fan impeller 12 is fixed to a rear portion of the rotor shaft 33 via a sleeve 12A. The fan impeller 12 is arranged between the rear rotor bearing 37 and the stator 26. The fan impeller 12 rotates due to the rotation of the rotor 27. Due to the rotation of the rotor shaft 33, the fan impeller 12 rotates together with the rotor shaft 33. Due to the rotation of the fan impeller 12, air flows from the outside of the housing 2 into the interior of the housing 2 via the air intake openings 19. Air that has flowed into the interior of the housing 2 flows through the interior of the housing 2, thereby cooling the motor 6.Due to the rotation of the fan wheel 12, air that has flowed through the interior of the housing 2 flows to the outside of the housing 2 via the air discharge openings 20.

[0108] The battery mounting part 13 is arranged at a lower portion of the battery holding part 23. The battery mounting part 13 is connected to the battery pack 25. The battery pack 25 is mounted on the battery mounting part 13. The battery pack 25 is removable from the battery mounting part 13. The battery pack 25 is mounted on the battery mounting part 13 by inserting it into the battery mounting part 13 from the front of the battery holding part 23. The battery pack 25 is removed from the battery mounting part 13 by pulling it forward from the battery mounting part 13. The battery pack 25 includes secondary batteries. In the embodiment, the battery pack 25 includes rechargeable lithium-ion batteries. By being mounted on the battery mounting part 13, the battery pack 25 can supply electric power to the impact tool 1. The motor 6 is driven using the electric power supplied from the battery pack 25.

[0109] The trigger lever 14 is provided on the handle part 22. The trigger lever 14 is operated by the user to start the motor 6 (manually). The motor 6 is switched between drive and stop by operating the trigger lever 14.

[0110] The forward-reverse switching lever 15 is provided at an upper portion of the handle 22. The forward-reverse switching lever 15 is operated (manually) by the user. By operating the forward-reverse switching lever 15, the rotation direction of the motor 6 is switched from one of the forward rotation direction and the reverse rotation direction to the other. Switching the rotation direction of the motor 6 switches the rotation direction of the spindle 8.

[0111] The interface panel 16 is provided on the battery holding part 23. The interface panel 16 is provided on an upper surface of the battery holding part 23, further to the front than the handle part 22. The interface panel 16 has operable buttons 16A. One or more of the operable buttons 16A may be provided. A plurality of operable buttons 16A is provided in the embodiment. By operating (pressing) one of the operable buttons 16A, the user can switch (change, change) the operation mode of the motor 6.

[0112] The quick mode switch button 17 is provided at an upper portion of the trigger lever 14. The quick mode switch button 17 is operated (manually) by the user. The operating mode of the motor 6 is switched (changed) by pressing the quick mode switch button 17.

[0113] The light assembly 18 emits an illumination light. The light assembly 18 illuminates the anvil 10 and the periphery of the anvil 10 with the illumination light. The light assembly 18 illuminates the front of the anvil 10 with the illumination light. In addition, the light assembly 18 illuminates the tool accessories mounted on the anvil 10 and the periphery of the tool accessories with the illumination light. In the embodiment, the light assembly 18 is arranged on the left side and right side of the large tube section 4A of the hammer housing 4.

[0114] The spindle 8 has an internal space 60. An opening is provided in a rear end surface of the spindle 8. The internal space 60 is formed in the interior of the spindle 8 such that it extends from the opening provided in the rear end surface of the spindle 8. The internal space 60 accommodates lubricating oil. The lubricating oil includes lubricating grease. A front end portion of the drive gear 41 is inserted into a rear end portion of the internal space 60 via the opening in the rear end surface of the spindle 8.

[0115] Fig. 9 is a flowchart illustrating a representative, non-limiting example of a manufacturing method of the spindle 8 according to the embodiment. As shown in Fig. 9, the manufacturing method of the spindle 8 includes a blank manufacturing step S10, a die arranging step S20, a forging step S30, a cutting step S40, and a heat treatment step S50.

[0116] A blank 70, which is a precursor of the spindle 8, is formed in the blank manufacturing step S10. The blank 70 can be formed using, for example, forging techniques or the like. In this case, the blank 70 can be formed at a temperature of -20°C or higher and 40°C or lower (cold forging), 300°C or higher and 850°C or lower (hot forging), or 1,000°C or higher and 1,250°C or lower (hot forging). Note that the temperature of the blank 70 can be any temperature during the blank manufacturing step S10, as long as the temperature is in the range of -20°C or higher and 1,250°C or lower. Specifically, a first flange corresponding portion 72B is formed when the blank 70 is forged.

[0117] Fig. 10 shows an example of the blank 70 according to the embodiment. The blank 70 has a shaft corresponding portion 71 and a flange corresponding portion 72. The shaft corresponding portion 71 is the portion corresponding to the spindle shaft portion 8A of the spindle 8.

[0118] The flange corresponding portion 72 is the portion corresponding to the flange portion 8L of the spindle 8. The flange corresponding portion 72 includes the above-described first flange corresponding portion 72B, which corresponds to the first flange portion 8B of the spindle 8, and connecting corresponding portions 72D, which correspond to the connecting portions 8D of the spindle 8. The first flange corresponding portion 72B has a disc or ring shape. Each of the connecting corresponding portions 72D has a shape in which a plate-like portion extends radially outward in three directions from the center of the axial direction. The connecting corresponding portions 72D are arranged such that the angles formed between adjacent connecting corresponding portions 72D are equal (e.g., 120°).It is noted that the angles formed between adjacent connection corresponding regions 72D among the plurality of connection corresponding regions 72D need not be equal.

[0119] A forging die 80 is arranged with respect to the blank 70 in the die arranging step S20. Fig. 11 shows an example of the forging die 80 according to the embodiment. Fig. 12 shows an example of the die arranging step S20 according to the embodiment. As shown in Fig. As shown in Figure 11, the forging die 80 includes a blank support portion 81 and slotted mating portions 82. The blank support portion 81 supports the blank 70. The blank support portion 81 includes a receiving portion 83 and tab portions 84.

[0120] The receiving part 83 receives the shaft corresponding portion 71 of the blank 70 and the first flange corresponding portion 72B of the flange corresponding portion 72. In the state in which the blank 70 is received in the receiving part 83, the tab portions 84 support outer peripheral side surfaces in the radial direction of the connecting corresponding portions 72D of the blank 70. Three of the tab portions 84 are arranged at equal widths (intervals) in the circumferential direction. In an embodiment in which the blank 70 is received in the receiving part 83, outer end portions of the three connecting corresponding portions 72D of the blank 70 are arranged to oppose the tab portions 84. The tab portions 84 position the slot corresponding portions 82.

[0121] The slot corresponding parts 82 are parts that correspond to the slot regions 8I of the spindle 8. The slot corresponding parts 82 are configured, for example, as a plurality of fan-like plate-shaped components. Inner peripheral regions of the slot corresponding parts 82 have shapes corresponding to the connecting corresponding regions 72D of the blank 70. As shown in Fig. As shown in FIG. 12, the slot corresponding parts 82 are arranged in the circumferential direction between mutually adjacent tab portions 84 in the state in which the blank 70 is accommodated in the receiving part 83. In other words, the slot corresponding parts 82 are arranged to fill between mutually adjacent connection corresponding portions 72D in the circumferential direction of the blank 70.

[0122] In the forging step S30, after the forging die 80 is arranged as described above, a rear end portion 72E of the flange corresponding portion 72 is struck in the axial direction to cause plastic deformation of the flange corresponding portion 72 along the slot corresponding parts 82 of the forging die 80. The forging step S30 can be carried out with the temperature of the blank 70 at, for example, about 25°C (cold forging).

[0123] Fig. 13A and Fig. 13B show an example of the forging step S30 according to the embodiment. As in Fig. 13A, during the forging step S30, a press hammer 85 having a diameter larger than the diameter of the flange corresponding portion 72 is used to strike the rear end portion 72E (ie, the above-described upsetting process is applied). In this upsetting process, as shown in Fig. As shown in Fig. 13B, the entire rear end portion 72E of the flange corresponding portion 72 may be flattened, causing plastic deformation of the rear end portion 72E to expand in the radial direction along the slit corresponding portions 82. This flattened, spread-out portion becomes a second flange corresponding portion 72C, which corresponds to the second flange portion 8C and the cylindrical portion 8E of the spindle 8. Further, the slit portions 8I are formed at the positions where the slit corresponding portions 82 are respectively located. After the plastic deformation of the flange corresponding portion 72, the slit corresponding portions 82 are removed, and the machined (further forged) blank 70 is removed from the receiving portion 83.

[0124] In the cutting step S40, the flange corresponding portion 72 is cut in the blank in which the flange corresponding portion 72 is elastically deformed. Fig. 14A and Fig. 14B show an example of the cutting step S40 according to the embodiment. As in Fig. 14A and Fig. 14B, for example, during the cutting step S40, radially inner portions of the connection corresponding portions 72D are cut, and radially outer portions are left to form the connection portions 8D of the spindle 8 and connect the slit portions 8I at the radially inner portions. Furthermore, the second flange portion 8C, the cylindrical portion 8E, and the insertion hole 8H are formed by cutting the second flange corresponding portion 72C. The shaft corresponding portion 7I and the first flange corresponding portion 72B may be left as they are and serve as the spindle shaft portion 8A and the first flange portion 8B. It is noted that the outer shapes of the first flange portion 8B and the connection portions 8D can be adjusted, if necessary, by cutting the outer peripheries of the first flange corresponding portion 72B and the connection corresponding portion 72D.In the cutting step S40, a cutting surface 8J is formed on a surface of the cut portion. Furthermore, the portions where no cutting is performed in the cutting step S40—that is, the portions opposite the openings 8P surrounded by the first flange portion 8B, the second flange portion 8C, and the three connecting portions 8D, respectively—become the non-cut portions 8K. Fig. Figure 14C schematically shows the granule flows in the solidified region of the spindle 8, which is formed according to the upsetting process described above. Fig. 14D shows spindle 8 of Fig. 14C, after the cutting step described above has been performed. As in Fig. 14C and Fig. 14D, in an embodiment in which forging is carried out by the upsetting process as described above with reference to Fig. 13A and Fig. 13B, the granule streams are formed spreading in the radial direction in the rear end portion 72E. By performing the cutting after forming the granule streams according to the upsetting method, the granule streams in the cylindrical portion 8E are separated (separated) from the other portions, specifically, from the second flange portion 8C.

[0125] Fig. 15A and Fig. 15B show another example of the forging step S30 according to the reverse extrusion method described above. As in Fig. 15A and Fig. 15B, during the forging step S30, the radially outer side of the flange corresponding portion 72 is surrounded by a different die 86, and a press hammer 85 smaller than the diameter of the flange corresponding portion 72 may be used to strike the central portion of the rear end portion 72E to perform the backward extrusion process. In this process, a central portion of the rear end portion 72E of the flange corresponding portion 72 may be flattened to be recessed relative to the peripheral edge portion, thereby causing plastic deformation of the rear end portion 72E such that the peripheral edge portion (ridge portion (ridge portion) 72F) rises rearward along the inner circumference of the die.By performing forging according to the reverse extrusion method, the shape of the outer circumference in the radial direction of the portion that will become the second flange corresponding portion 72C can be formed in a shape that matches the die. Note that the rear end portion 72E, from which the rib portion 72F is formed, becomes a shape that matches the cylindrical portion 8E.

[0126] Fig. 16A and Fig. 16B show another example of the cutting step S40. That is, in an embodiment in which the forging step S30 is carried out using the reverse extrusion method described above, the flange corresponding portion 72 is cut in the cutting step S40, as shown in Fig. 16A and Fig. 16B. In the cutting step S40, the cylindrical portion 8E is formed by, for example, cutting the rib portion 72F. Further, for example, radially inner portions of the connection corresponding portion 72D are cut, and radially outer portions remain to form the connection portions 8D of the spindle 8 and connect the slit portions 8I at the radially inner portions. Further, by cutting the second flange corresponding portion 72C after cutting the rib portion 72F, the second flange portion 8C and the insertion hole 8H are formed. The shaft corresponding portion 71 and the first flange corresponding portion 72B may remain as they are to serve as the spindle shaft portion 8A and the first flange portion 8B.Note that the outer shapes of the first flange portion 8B and the connecting portions 8D can be adjusted, if necessary, by cutting the outer peripheries of the first flange corresponding portion 72B and the connecting corresponding portions 72D. In the cutting step S40, a cutting surface 8J is formed on a surface of the portion that was cut. Furthermore, the portions where no cutting was performed in the cutting step S40—that is, the portions opposite the three openings 8P surrounded by the first flange portion 8B, the second flange portion 8C, and the plurality of connecting portions 8D, respectively—become the non-cutting portions 8K. Fig. 16C schematically shows the granule flows in the fixed portion of the spindle 8 according to the embodiment, which are formed using the backward extrusion method. Fig. 16D shows spindle 8 of Fig. 16C after performing the cutting step described above. As in Fig. 16C and Fig. 16D, in an embodiment in which forging is performed using the reverse extrusion method, the granule streams are formed curving from the central portion of the rear end portion 72E into the rear end of the rib portion 72F. When the granule streams are formed in this way, by cutting the rib portion 72F to form the cylindrical portion 8E, the granule streams are connected (continuously) from the central portion in the radial direction of the rear end portion of the second flange portion 8C to the cylindrical portion 8E.

[0127] In the heat treatment step S50, a heat treatment is performed on the blank 70 after it has been forged and cut. During the heat treatment step S50, the blank 70 is preferably subjected to a heat treatment so that the surface hardness of the cut blank 70 becomes 300 HV or greater. Any process can be performed during the heat treatment step S50 as long as it is a process in which heating is performed so that a property (preferably its surface hardness) of the material of the blank 70 changes, for example, quenching, such as immersion quenching, carburizing and quenching, carbonitriding and quenching, and induction hardening or an age hardening process, etc.

[0128] The operation of the impact tool 1 is described below. For example, when performing screw tightening work on a workpiece (e.g., a screw), the tool accessory used for the screw tightening work (a screw bit) is inserted into the tool hole 10C of the anvil 10. The tool accessory inserted into the tool hole 10C is held by the tool holding mechanism 11. After the tool accessory is mounted on the anvil 10, the user grasps the handle portion 22 with, for example, his right hand and presses the trigger lever 14 with the index finger of his right hand. When the trigger lever 14 is pressed, electric power from the battery pack 25 is supplied to the motor 6, the motor 6 starts, and the light assembly 18 turns ON at the same time. By starting the motor 6, 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 gears 42 via the drive gear 41. In the state where the planetary gears 42 mesh with the internal teeth of the internal gear 43, the planetary gears 42 revolve around the drive gear 41 while rotating. The planetary gears 42 are rotatably supported by the spindle 8 via the pins 42P. Due to the revolution of the planetary gears 42, the spindle 8 rotates at a speed lower than the speed of the rotor shaft 33.

[0129] In the state in which the hammer 47 and the anvil protruding portions 10B are continuously in contact with each other, when the spindle 8 rotates, the anvil 10 rotates together with the hammer 47 and the spindle 8. The screw tightening work progresses due to the rotation of the anvil 10.

[0130] The rotation of the anvil 10 and the hammer 47 temporarily stops when a load greater than or equal to a predetermined value acts on the anvil 10 due to the progress of the screw tightening work. When the spindle 8 continues to rotate in this state in which the rotation of the hammer 47 is temporarily stopped, the hammer 47 moves backward. Due to the backward movement of the hammer 47, contact between the hammer protrusion portions 47D and the anvil protrusion portions 10B is released. After moving backward, the hammer 47 moves forward while rotating due to the elastic force of the coil spring 49. The anvil 10 is struck by the hammer 47 in the rotational direction due to the hammer 47 moving forward while rotating. As a result, the anvil 10 rotates around a rotational axis AX with high torque. As a result, the screw in the workpiece is tightened.

[0131] As described above, in the present embodiment, the impact tool 1 may include the motor 6, the drive gear 41 rotated by the motor 6, at least three planetary gears 42 meshing with the drive gear 41, the internal gear 43 meshing with the planetary gears 42, the spindle 8 having the flange portion 8L—which has the insertion hole 8H located in the axial direction for inserting the drive gear 41 and the slot portions 8I in at least one side surface thereof for mounting the planetary gears 42—and the spindle shaft portion 8A extending forward from the flange portion 8L in the axial direction, in which the flange portion 8L is formed by forging, the hammer 47 held by the spindle 8, the anvil 10 struck by the hammer 47 in the rotational direction, the hammer housing 4,which receives the hammer 47 and holds the anvil 10 in a rotatable manner, the tool accessory holding part (tool holding mechanism 11) which is provided on (in) the anvil 10, and the coil spring 49 which biases the hammer 47 towards the side of the anvil 10.

[0132] With the configuration described above, it becomes possible to reduce the time required for manufacturing the impact tool 1 by adopting a spindle 8 in which the flange portion 8L (specifically, the second flange portion 8C) has been formed (formed) by forging.

[0133] In the present embodiment, the flange portion 8L may have the cut surface 8J at least at a portion on the surface.

[0134] In the configuration described above, the accuracy of the outer shape of the spindle 8 can be improved, if necessary and if appropriate, by cutting the surface of the flange portion 8L formed (formed) by forging.

[0135] The present embodiment may further include the balls 48 disposed between the spindle 8 and the hammer 47, and the spindle 8 may include the spindle grooves 8G in the spindle shaft portion 8A, in each of which at least a part of the corresponding ball 48 is disposed.

[0136] With the configuration described above, the time required for manufacturing can be reduced if the spindle 8 is manufactured having the spindle grooves 8G in the spindle shaft portion 8A, in each of which at least a part of the corresponding ball 48 is arranged.

[0137] In the embodiment, the spindle 8 may be formed using a steel containing 0.13% or more and 1.00% or less of carbon and 0.90% or more of chromium.

[0138] In the configuration described above, since plastic deformation of the spindle can be effected by forging, if appropriate, it is possible to ensure the strength after deformation of the same.

[0139] In the present embodiment, the granule streams 8T may be formed in the flange portion 8L of the spindle 8 by forging such that the granule streams 8T extend (extend) outward from the center of the radial direction.

[0140] In the configuration described above, since the flange portion 8L of the spindle 8 has the granule flows 8T formed by forging so as to extend outward from the center of the radial direction, appropriate strength of the spindle can be ensured.

[0141] In the present embodiment, the spindle 8 may have the first flange portion 8B connected to the spindle shaft portion 8A, the second flange portion 8C arranged opposite to the first flange portion 8B at the rear of the first flange portion 8B, and (preferably three) connecting portions 8D connecting the first flange portion 8B and the second flange portion 8C to each other in the axial direction.

[0142] With the configuration described above, the time required for manufacturing can be reduced when manufacturing the spindle 8 configured to have the first flange portion 8B, the second flange portion 8C, and the connecting portions 8D.

[0143] In the present embodiment, the connecting portions 8D are arranged in a circumferential direction, and each of the planetary gears 42 may be arranged between mutually adjacent connecting portions 8D at locations sandwiched between the first flange portion 8B and the second flange portion 8C.

[0144] In the configuration described above, the time required for manufacturing can be reduced if the spindle 8 is manufactured which is configured such that each of the planetary gears 42 is respectively arranged between the mutually adjacent connecting portions 8D at positions sandwiched between the first flange portion 8B and the second flange portion 8C.

[0145] In the present embodiment, portions of the spindle 8 opposite to the openings 8P surrounded (defined) by the first flange portion 8B, the second flange portion 8C, and the connecting portions 8D may be the non-intersecting portions 8K, that is, the openings 8P are formed only by forging.

[0146] In the configuration described above, since the openings of the slit portions 8I can be formed as the non-cut portions 8K, respectively, cutting need not be performed when these openings are formed.

[0147] In the present embodiment, the spindle 8 can be used in a power tool and can have the flange portion 8L - having the insertion hole 8H located in the axial direction for inserting the drive gear 41 and the slit portions (gap portions) 8I in at least one side surface thereof for respectively mounting the planetary gears 42 - and the spindle shaft portion 8A extending forward from the flange portion 8L, the flange portion 8L being formed (formed) by forging.

[0148] With the configuration described above, it becomes possible to reduce the time required to manufacture the spindle 8 because the flange portion 8L is formed by forging.

[0149] In the present embodiment, the flange portion 8L may have the cut surface 8J on at least a portion of a surface.

[0150] In the configuration described above, the accuracy of the outer shape of the spindle 8 can be improved, if necessary and if appropriate, by cutting the surface of the flange portion 8L formed by forging.

[0151] In the present embodiment, the spindle shaft portion 8A may have the spindle grooves 8G, in each of which at least a part of the corresponding ball 48 is arranged.

[0152] With the configuration described above, the time required for manufacturing can be reduced if the spindle 8 is manufactured having the spindle grooves 8G in the spindle shaft portion 8A, in each of which at least a part of the corresponding ball 48 is arranged.

[0153] In the present embodiment, the spindle 8 can be formed using a steel containing 0.13% or more and 1.00% or less of carbon and 0.90% or more of chromium.

[0154] In the configuration described above, since it is possible to cause the plastic deformation of the spindle, if appropriate, by forging, it becomes possible to ensure the post-deformation strength of the same.

[0155] In the present embodiment, the granule streams 8T in the flange portion 8L may be formed by forging such that at least some of the granule streams 8T extend outward from the center of the radial direction.

[0156] In the configuration described above, since the granule flows 8T in the flange portion 8L are formed by forging to extend outward from the center of the radial direction, appropriate strength of the spindle can be ensured.

[0157] In the present embodiment, the flange portion 8L may include the first flange portion 8B connected to the spindle shaft portion 8A, the second flange portion 8C disposed opposite to the first flange portion 8B at the rear of the first flange portion 8B, and the connecting portions 8D connecting the first flange portion 8B and the second flange portion 8C to each other in the axial direction.

[0158] With the configuration described above, the time required for manufacturing can be reduced if the flange portion 8L of the spindle 8 is manufactured, which is configured to have the first flange portion 8B, the second flange portion 8C and the connecting portions 8D.

[0159] In the present embodiment, the connecting portions 8D may be arranged in a circumferential direction, and each of the planetary gears 42 may be arranged between mutually adjacent connecting portions 8D at a position sandwiched between the first flange portion 8B and the second flange portion 8C.

[0160] In the configuration described above, the manufacturing time can be reduced if the spindle 8 is manufactured which is configured such that each of the planetary gears 42 is arranged between mutually adjacent connecting portions 8D at a position sandwiched (provided) between the first flange portion 8B and the second flange portion 8C.

[0161] In the present embodiment, portions of the flange portion 8L that are opposite to the openings 8P surrounded by the first flange portion 8B, the second flange portion 8C, and the plurality of connecting portions 8D may be the non-intersecting portions 8K.

[0162] In the configuration described above, since the openings of the slit regions 8I can be formed as the non-cut regions 8K, cutting need not be performed when these openings are formed.

[0163] In the present embodiment, the method of manufacturing the spindle 8 having the flange portion 8L having the insertion hole 8H located in the axial direction for inserting the drive gear 41 and the slit portions 8I in at least one side surface thereof for mounting the planetary gears 42 and the spindle shaft portion 8A extending forward from the flange portion 8L, the spindle 8 being used in a power tool, the manufacturing method may include: (i) forming (providing) the blank 70 having the flange corresponding portion 72 and the shaft corresponding portion 71 corresponding to the flange portion 8L and the slit portion 8I, respectively;the spindle shaft portion 8A, (ii) arranging with respect to the flange corresponding portion 72 of the blank 70 the forging die 80 in which the slit corresponding parts 82 corresponding to the slit portions 8I are formed, and (iii) forming the slit portions 8I by forging in which the rear end portion 72E of the flange corresponding portion 72 is struck in the axial direction in a state in which the forging die 80 is arranged to cause plastic deformation of the flange corresponding portion 72 along the slit corresponding parts 82 of the forging die 80.

[0164] With the configuration described above, in the state where the forging die 80—in which the slot corresponding part 82 corresponding to the slotted portions 8I is formed—is positioned with respect to the flange corresponding portion 72 of the blank 70, the slotted portions 8I are formed by forging in which the rear end portion 72E of the flange corresponding portion 72 is struck in the axial direction to cause plastic deformation of the flange corresponding portion 72 along the slotted portions 82 of the forging die 80. Accordingly, the time required for manufacturing the spindle 8 can be reduced because the slotted portions 8I can be efficiently formed by forging.

[0165] In the present embodiment, the flange portion 8L of the spindle 8 may have the insertion hole 8H in the axial direction for inserting the drive gear 41, and the manufacturing method may further include forming the insertion hole 8H by cutting the flange corresponding portion 72 after the plastic deformation of the flange corresponding portion 72.

[0166] In the configuration described above, since the insertion hole 8H is formed by cutting after forming the slit portions 8I by forging, the time required for manufacturing the spindle 8 can be reduced compared to an embodiment in which both the slit portions 8I and the insertion hole 8H are formed by cutting.

[0167] In the present embodiment, the blank 70 can be formed by forging in the state where the temperature of the material is -20°C or higher and 40°C or lower, 300°C or higher and 850°C or lower, or 1,000°C or higher and 1,250°C or lower, and the spindle can be formed by forging in the state where the temperature of the forged blank 70 is -20°C or higher and 40°C or lower.

[0168] With the configuration described above, the blank 70 can be suitably manufactured, and the spindle 8 can be manufactured using the suitably manufactured blank 70.

[0169] In the present embodiment, the spindle 8 can be formed such that the surface hardness thereof after forming forging becomes 300 HV or greater by heat treatment.

[0170] With the configuration described above, it is possible to ensure the strength of the spindle 8 because the surface hardness thereof after being formed by forging becomes 300 HV or greater due to the heat treatment.

[0171] In the embodiment described above, the power supply of the impact tool is not required to be the battery pack 25 and may be a commercial power source (AC power source).

[0172] In the embodiment described above, the power tool is assumed to be the impact tool 1, and the impact tool 1 is assumed to be an impact wrench. The impact tool 1 may be an impact wrench. Furthermore, the power tool may be a drill driver, a polisher, a pencil cutter, or a hammer drill.

[0173] It is explicitly emphasized that all features disclosed in the description and / or the claims are to be considered separate and independent of each other for the purpose of the original disclosure as well as for the purpose of limiting the claimed invention, regardless of the feature combinations in the embodiments and / or the claims. It is explicitly stated that all range specifications or specifications of groups of units disclose every possible intermediate value or subgroup of units for the purpose of the original disclosure as well as for the purpose of limiting the claimed invention, in particular also as a limit of a range specification. List of reference symbols S10 Blank manufacturing step S20 Die arrangement step S30 forging step S40 Cutting step AX rotation axis 1 impact tool 2 housings 2L left housing 2R right housing 2S, 3S, 30S screws 3 rear cover 4 hammer housings 4A large pipe area 4B small pipe area 6 Engine 7 Speed ​​reduction mechanism 8 spindle 8A spindle shaft 8B first flange area 8C second flange area 8D connection area 8E cylindrical area 8F spindle protrusion area 8G spindle groove 8H insertion hole 8I slot area 8J cutting surface 8K non-editing area 8L flange range 8S outer peripheral surface 8T granulate flow 9 Impact mechanism 10 anvils 10A Anvil shaft area 10B Anvil protrusion area 10C tool hole 10D anvil recess area 11 Tool holding mechanism 12 Fan wheel 12A sleeve 13 Battery mounting part 14 push levers 15 Forward-reverse gear lever 16 Interface panel 16A actuatable button 17 Quick mode switch button 18 Lighting assembly 19 Air intake opening 20 Air discharge opening 21 Engine housing part 22 Handle part 23 Battery holder 24 storage boxes 24A rear annular area 25 battery pack 26 Stator 27 Rotor 28 Stator core 29 rear insulating piece 30 front insulating piece 31 coil 32 rotor core 33 Rotor shaft 34A rotor magnet 34B Sensor magnet 35 Sensor board 36 fuse connection 37 rear rotor bearing 38 front rotor bearing 41 Drive gear 42 planetary gear 42P pin 43 Internal gear 44 spindle bearings 45 O-ring 46 anvil bearings 47 Hammer 47A Body area 47C inner tube area 47D Hammer protrusion area 47E exempt area 47G Hammernut 47S inner peripheral surface 48, 54 balls 49 coil spring 50, 56 washers 51 Hammer housing cover 52 shock absorbers 57 Bearing component 60 interior 70 blank 71 shaft equivalent area 72 Flange correspondence range 72B first flange correspondence area 72C second flange correspondence area 72D Connection Correspondence Area 72E rear end area 80 forging die 81 Blank storage part 82 slot correspondence part 83 Recording part 84 tab section 85 Jackhammer QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2021 - 037 561 B2

[0002]

Claims

[1] Striking tool, with an engine, a sun gear that is rotated by the motor, at least three planetary gears that mesh with the sun gear, an internal gear that meshes with the planetary gears, a spindle having a flange portion having a hole in an axial direction for inserting the sun gear and slot portions in at least one side surface thereof for mounting the planetary gears, and a shaft portion extending forward from the flange portion in the axial direction, at least a portion of the flange portion being formed by forging, a hammer which is held on the spindle, an anvil configured to be struck by the hammer in a rotational direction, a hammer housing which houses the hammer and holds the anvil in a rotatable manner, a tool accessory holding part which is provided on the anvil, and a coil spring that biases the hammer towards the anvil. [2] The impact tool of claim 1, wherein the flange portion has a cutting surface on at least a portion of a surface. [3] Impact tool according to claim 1 or 2, further comprising a ball arranged between the spindle and the hammer, in which the spindle has a spindle groove in the shaft region in which at least part of the ball is arranged. [4] Impact tool according to one of the preceding claims, wherein the spindle is formed using steel containing 0.13 to 1.00 mass percent carbon and at least 0.90 mass percent chromium. [5] An impact tool according to any one of the preceding claims, wherein granulate streams in the flange portion of the spindle are formed by forging to extend outwardly from the center of the radial direction. [6] Impact tool according to one of the preceding claims, in which the spindle a first flange portion connected to the shaft portion, a second flange portion disposed opposite and rearward of the first flange portion, and at least one connecting portion connecting the first flange portion and the second flange portion to each other in the axial direction. [7] Impact tool according to claim 6, in which a plurality of the connecting portions are arranged in the circumferential direction and connect the first flange portion and the second flange portion to each other in the axial direction, and each of the planetary gears is arranged between mutually adjacent connecting portions at a location sandwiched between the first flange and the second flange. [8] An impact tool according to claim 6 or 7, wherein portions of the spindle opposite the openings surrounded by the first flange, the second flange and the plurality of connecting portions are non-cutting portions. [9] Spindle used in a power tool with a flange portion having a hole in an axial direction for inserting a sun gear and slot portions in at least one side surface thereof for mounting planetary gears, and a shaft portion extending forward from the flange portion, in which the flange area was formed by forging. [10] A spindle according to claim 9, wherein the flange portion has a cut surface on at least a portion of a surface. [11] Spindle according to claim 9 or 10, wherein the shaft portion has a spindle groove in which at least part of a ball can be arranged. [12] Spindle according to one of claims 9 to 11, wherein the spindle is formed using steel containing 0.13 to 1.00 mass percent carbon and at least 0.90 mass percent chromium. [13] A spindle according to any one of claims 9 to 12, wherein granule flows in the flange portion are formed by forging to extend outwardly from the center of the radial direction. [14] Spindle according to one of claims 9 to 13, wherein the flange region a first flange connected to the shaft portion, a second flange arranged opposite the first flange and rearward of the first flange, and a connecting portion connecting the first flange and the second flange to each other in the axial direction. [15] Spindle according to claim 14, wherein a plurality of connecting regions are arranged in a circumferential direction, and each of the planetary gears is arranged between mutually adjacent connecting portions at a location sandwiched between the first flange and the second flange. [16] A spindle according to claim 14 or 15, wherein portions of the flange opposite the openings surrounded by the first flange and the second flange and the plurality of connecting portions are non-intersecting portions. [17] A method of manufacturing a spindle having a flange portion having a hole in an axial direction for inserting a sun gear and a slot portion in at least one side surface thereof for mounting a planetary gear, and a shaft portion extending forward from the flange portion, the spindle being used in a power tool, the manufacturing method comprising: Providing a blank having a flange corresponding region and a shaft corresponding region corresponding to the flange region and the shaft region, respectively, Arranging, with respect to the flange corresponding portion of the blank, a die in which a slot corresponding portion corresponding to the slot portion is formed, and Forming the slit portion by forging, in which, in the state in which the die is arranged, a rear end portion of the flange corresponding portion is struck in the axial direction to cause plastic deformation of the flange corresponding portion along the slit corresponding part of the die. [18] A method of manufacturing the spindle according to claim 17, further comprising forming the hole by cutting the flange corresponding portion after plastically deforming the flange corresponding portion. [19] A method for manufacturing the spindle according to claim 17 or 18, wherein the blank is formed by forging in a state in which the temperature of the material is -20°C or higher and 40°C or lower, 300°C or higher and 850°C or lower, or 1,000°C or higher and 1,250°C or lower, and the spindle is formed by forging in which the temperature of the forged blank is -20°C or higher and 40°C or lower. [20] A method of manufacturing the spindle according to any one of claims 17 to 19, further comprising heat-treating the spindle after forming by forging until the surface hardness of the spindle becomes 300 HV or greater.

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