Cutting grindstone mounting structure

Abstract

[Problem] To provide a cutting grindstone mounting structure which is capable of stably supplying a cooling liquid to a cutting grindstone, and is capable of detachably and properly mounting the cutting grindstone on a drive shaft.　[Solution] A cutting grindstone 20 mounting structure, which is capable of supplying a cooling liquid, is provided with: a drive shaft 11 that is composed of a rotation stop shaft part 11a and a male screw-like shaft part 11b; an inner flange 61 that is engaged with the rotation stop shaft part 11a and receives the cutting grindstone 20; a lock nut 62 that is screwed to the male screw-like shaft part and holds and fixes the cutting grindstone; cooling liquid introduction mechanisms 84, 86 that are configured in the drive shaft 11 and / or the lock nut 62 and guide the supplied cooling liquid to the inflow port 35a; and a supply joint part 63 that comprises a connection male screw member 92 which is connected to the cooling liquid introduction mechanisms 84, 86 through a flow passage and a joint body 91 which is connected to a cooling liquid supply source through the flow passage.

Description

Cutting wheel mounting structure

[0001] The present invention relates to a cutting wheel mounting structure for mounting a cutting wheel on a cutting device such as a disc grinder, and more particularly to a structure that enables a coolant to be supplied to a cutting wheel that requires a coolant.

[0002] A known mounting structure for this type of cutting wheel is one in which a rotary blade having a through-hole for a cooling medium is fitted onto a hollow drive shaft having a fluid flow path (see Patent Document 1). This device includes a drive shaft with a hollow portion as the fluid flow path, a manifold through which the drive shaft passes in a watertight and rotatable manner, and a liquid supply source that supplies the cooling medium to the manifold via a conduit. The rotary blade is fitted onto the tip of the drive shaft. The cooling medium from the supply source is supplied to the manifold via the conduit. In the manifold, the cooling medium is supplied to the fluid flow path of the rotating drive shaft from an open end on the manifold side, and further supplied to the through-hole of the rotary blade from an open end of the rotary blade formed at the tip. The cooling medium that flows into the rotary blade is supplied to the cutting portion via the through-hole and the hole.

[0003] Japanese Utility Model Application Publication No. 64-42108

[0004] In the conventional mounting structure, in which the rotary blade (cutting wheel) is fitted to the drive shaft through a mounting hole, the hollow portion of the drive shaft serves as a fluid flow path for the coolant, the fitting portion is weak, which has led to the problem that it is not possible to simultaneously supply coolant to the rotary blade (cutting wheel) stably and detachably and properly mount the rotary blade on the drive shaft.

[0005] The present invention aims to provide a cutting wheel mounting structure that can simultaneously provide a stable supply of coolant to the cutting wheel and detachably and appropriately mount the cutting wheel on the drive shaft.

[0006] The cutting wheel mounting structure of the present invention is a cutting wheel mounting structure capable of supplying coolant to a cutting wheel having a coolant flow inlet formed in the hole forming portion of the mounting hole during rotational driving, and includes a drive shaft which comprises a rotation prevention shaft portion provided on the device body side and a male threaded shaft portion protruding from the rotation prevention shaft portion and which rotates the mounted cutting wheel, an inner flange which engages with the rotation prevention shaft portion and receives the cutting wheel mounted on the male threaded shaft portion, a lock nut which has a female threaded portion which screws onto the male threaded shaft portion and clamps and fixes the cutting wheel between the inner flange, and a lock nut which screws onto the drive shaft. and a supply joint portion having an axial rotating portion coaxial with the drive shaft and connected to the coolant introducing mechanism and a non-rotating member portion connected to the coolant supply source, wherein the axial rotating portion has an axial flow path communicating with the coolant introducing mechanism, and the non-rotating member portion has an annular liquid reservoir surrounding the axial rotating portion and communicating with the axial flow path from the radial direction, and a connection port portion communicating with the annular liquid reservoir and to which the coolant supply source is connected.

[0007] This configuration allows the cut-off wheel to be securely attached (mounted) to the drive shaft by clamping it between the inner flange and the lock nut. This allows the cut-off wheel to be detachably and appropriately mounted on the drive shaft. Furthermore, in this state, coolant can be supplied to the cut-off wheel from the supply joint via the coolant introduction mechanism. In this case, the coolant is guided from the annular reservoir connected to the connection port of the non-rotating member, through the axial flow path of the axial rotating member, and then to the coolant introduction mechanism. This allows the coolant to be smoothly supplied from the non-rotating member to the rotating coolant introduction mechanism and the cut-off wheel. This allows for a stable supply of coolant to the cut-off wheel.

[0008] In this case, it is preferable that the coolant introduction mechanism has an annular coolant reservoir configured between the lock nut and the cutting wheel so that the inlet faces the reservoir, and an introduction flow path portion whose upstream side is connected to the axial flow path and whose downstream side is connected to the coolant reservoir.

[0009] With this configuration, the cut-off wheel, clamped and fixed between the inner flange and the lock nut, has a coolant inlet facing the annular coolant reservoir. Meanwhile, coolant flowing in from the inlet flow channel of the supply joint is guided to the coolant reservoir through the inlet flow channel. The coolant in the coolant reservoir is then supplied to the cut-off wheel through the inlet. Because centrifugal force acts on the coolant supplied to the rotating cut-off wheel, the coolant flowing in from the supply joint is smoothly guided to the cut-off wheel via the inlet flow channel and the coolant reservoir.

[0010] In this case, it is preferable that the inlet flow path portion has a recessed flow path formed in the inner peripheral surface of the female thread-shaped portion and extending axially from the coolant reservoir along the female thread-shaped portion, and a communication flow path connecting the recessed flow path and the axial flow path.

[0011] With this configuration, simply forming an axially extending recessed channel in the female threaded portion of the lock nut that screws onto the male threaded shank allows a coolant channel to be formed near the axial center without impairing the thread function of the lock nut. Preferably, a pair of axially extending recessed channel are formed at positions 180° symmetrical about a point in the circumferential direction.

[0012] Similarly, it is preferable that the introduction flow path portion has an annular groove flow path formed on the outer peripheral surface of the male threaded shaft portion so as to face the coolant reservoir, a straight flow path formed on the outer peripheral surface of the male threaded shaft portion and extending from the annular groove flow path to the tip of the male threaded shaft portion, and a communication flow path connecting the straight flow path and the axial flow path.

[0013] With this configuration, a coolant flow path can be easily formed near the axis by simply forming an annular groove flow path and a linear flow path connected to the annular groove flow path on the outer circumferential surface of the male threaded shaft portion. Preferably, a pair of linear flow paths extending in the axial direction are formed at positions 180° symmetrical about a point in the circumferential direction.

[0014] Similarly, it is preferable that the introduction flow path portion has a radial hole flow path formed on the outer peripheral surface of the male threaded shaft portion so as to face the coolant reservoir, an axial hole flow path formed in the axial center portion of the male threaded shaft portion and extending from the radial hole flow path to the tip of the male threaded shaft portion, and a communication flow path connecting the axial hole flow path and the axial center flow path.

[0015] According to this configuration, a coolant flow path can be easily formed at or near the axis by simply forming a radial hole flow path and an axial hole flow path connected to the radial hole flow path in the male threaded shaft portion. Note that the radial hole flow path preferably penetrates the male threaded shaft portion in the radial direction.

[0016] Furthermore, it is preferable that the drive shaft has an extension shaft portion that is connected to the base end side of the male threaded shaft portion and extends through the device body to the opposite side, and that the supply joint portion is attached to the extension shaft portion, and that the introduction flow path portion has a radial hole flow path formed on the outer peripheral surface of the male threaded shaft portion so as to face the coolant reservoir, an extended axial hole flow path formed in the axial portion of the male threaded shaft portion and the extension shaft portion and extending from the radial hole flow path to the tip of the extension shaft portion, and a communication flow path that communicates the extended axial hole flow path and the axial flow path.

[0017] With this configuration, the inner flange, cut-off wheel, and lock nut are attached to one end of the drive shaft that penetrates the device body, and the supply joint is attached to the other end, so the weight balance of the device body is maintained when it is operated by hand, and operability is not impaired. Meanwhile, by simply forming radial hole passages and extended axial hole passages connected to them in the male threaded shaft portion and the extension shaft portion, a coolant flow passage can be easily formed at the axis center and near the axis center.

[0018] On the other hand, the inner flange preferably has a first seal member that seals against the cutoff wheel, and a second seal member that seals against the male threaded shaft portion.

[0019] With this configuration, the first seal member seals between the inner flange and the cutting wheel, and the second seal member seals between the inner flange and the male threaded shaft, so that the coolant does not leak down the inner flange or the male threaded shaft into the device body, effectively preventing the coolant from accidentally entering the device body.

[0020] The lock nut preferably has a third seal member for sealing between the lock nut and the cutting wheel.

[0021] According to this configuration, the third seal member seals the gap between the lock nut and the cutting wheel, so that the coolant does not leak out of the lock nut, effectively preventing unnecessary leakage of the coolant.

[0022] 1 is a perspective view of the appearance of a cutting device according to an embodiment; FIG. 2 is a perspective view of the appearance of the cutting device with the disc cover removed; FIG. 3 is a plan view (a) and a cut-off side view (b) of a cut-off wheel according to an embodiment; FIG. 4 is an enlarged plan view (a) and an enlarged cut-off side view (b) of a cut-off wheel according to a first modified example; FIG. 5 is an enlarged plan view (a) and an enlarged cut-off side view (b) of a cut-off wheel according to a second modified example; FIG. 6 is a cut-off side view showing a mounting structure for a cut-off wheel according to the first embodiment; FIG. 7 is an exploded cut-off side view showing a mounting structure for a cut-off wheel according to the first embodiment; FIG. 8 is a front view (a), a side view (b), and a back view (c) of an inner flange in the mounting structure; FIG. 9 is a front view (a), a side view (b), and a back view (c) of a lock nut in the mounting structure; FIG. 10 is a side view (a), a back view (b), and a bottom view (c) of a joint body in a coolant joint portion; FIG. 11 is a front view (a), a side view (b), and a back view (c) of a connecting male screw member in a coolant joint portion. 10A and 10B are cross-sectional side views showing a mounting structure of a cutting wheel according to a second embodiment, a cross-sectional side view showing a mounting structure of a cutting wheel according to a third embodiment, and a cross-sectional side view showing a mounting structure of a cutting wheel according to a fourth embodiment.

[0023] With reference to the accompanying drawings, a cutting wheel mounting structure according to one embodiment of the present invention will be described when applied to a cutting device. This cutting device has the basic form of a disc grinder, and is equipped with a disc-shaped cutting wheel to grind and cut concrete, mortar, tile, etc. The cutting wheel of the embodiment has an internal coolant flow path, and the cutting device has the functions of supplying coolant to the cutting wheel and recovering waste coolant mixed with grinding powder when cutting an object. Therefore, although not shown in these figures, a coolant supply device and a waste coolant recovery device, which constitute a coolant supply source, are connected to the cutting device.

[0024] [Cutting Device] Fig. 1 is an external perspective view of a cutting device according to an embodiment. Fig. 2 is an external perspective view of the cutting device with a disc cover removed. As shown in these figures, the cutting device 10 has the basic configuration of a so-called disc grinder, with an exposed drive shaft 11 for attaching a cutting wheel 20 (disc), and includes a motor 12 having the drive shaft 11, a device body 13 incorporating the motor 12, a mounting unit 14 for supplying coolant to the cutting wheel 20 attached to the drive shaft 11, and a disc cover 16 for covering the cutting wheel 20. The drive shaft 11 and the mounting unit 14 constitute a mounting structure 15 for the cutting wheel 20 as claimed.

[0025] The cutting device 10 also includes a cover holder 17 for holding the disc cover 16 on the device body 13, and an anti-rotation arm 18 for preventing rotation of a part of the mounting unit 14. As will be described in detail later, a cooling liquid supply device (see FIG. 6) is connected to the mounting unit 14 of the cutting device 10 configured in this manner via a liquid supply tube 21, and a cooling liquid waste recovery device (not shown) is connected to the disc cover 16 via a waste liquid tube 22.

[0026] The device body 13, which houses the motor 12, is roughly cylindrical as a handheld power tool, with a disk mounting base 24 disposed at the tip end and the drive shaft 11 protruding from the center of the disk mounting base 24. A power cord 25 is connected to the base end of the device body 13. The power cord 25, the liquid supply tube 21, and the liquid waste tube 22 are bundled together so as not to interfere with operation.

[0027] [Cutting Wheel] Fig. 3 is a structural diagram of the cutting wheel. As shown in the figure, the cutting wheel 20 is a so-called diamond wheel, and includes a disk-shaped blade substrate 31 having a central mounting hole 32 for mounting to the drive shaft 11, a plurality of (eight) segmented tips 33 brazed to the outer periphery of the blade substrate 31, a plurality of (eight) relief grooves 34 formed in the outer periphery of the blade substrate 31, and a plurality of (eight) coolant flow paths 35 formed radially inside the blade substrate 31. The blade substrate 31 is formed by bonding a thin disk-shaped first substrate 40 and a thin disk-shaped second substrate 50 together (see Fig. 3(b)).

[0028] The first substrate 40 is formed with a first mounting hole 41 that constitutes the mounting hole 32, eight first U-shaped grooves 42 that constitute the relief groove 34, and eight first flow path grooves 43 that constitute the coolant flow path 35. Similarly, the second substrate 50 is formed with a second mounting hole 51 that constitutes the mounting hole 32, eight second U-shaped grooves 52 that constitute the relief groove 34, and eight second flow path grooves 53 that constitute the coolant flow path 35. The blade substrate 31 is formed by butting together the back surfaces of the first substrate 40 and the second substrate 50 thus formed and spot welding them at eight welding locations 55 (see FIG. 3( a)).

[0029] The cutting wheel 20 configured in this manner is attached to the drive shaft 11 so that the first substrate 40 is located on the inside (toward the device body 13) and the second substrate 50 is located on the outside. Meanwhile, the second attachment hole 51 is formed with a larger diameter than the first attachment hole 41 (see FIG. 3(b)). As a result, an attachment hole 32 having an annular step 32a is formed in the center of the blade substrate 31. That is, the annular step 32a is formed in the hole forming portion of the attachment hole 32. As will be described in detail later, in the cutting wheel 20 of this embodiment, coolant is supplied from this annular step 32a.

[0030] An inlet 35a of each coolant flow path 35 opens in the annular step 32a, and an outlet 35b of each coolant flow path 35 opens at the bottom of each escape groove 34. Therefore, in the cutting wheel 20, the coolant flows radially from the annular step 32a to the coolant flow paths 35 and is further supplied to the segment chips 33 via the escape grooves 34.

[0031] The annular step portion 32a forms an annular liquid pool facing the inlet 35a of the coolant flow path 35, but the structure corresponding to this liquid pool may be as follows.

[0032] 4 shows the structure of a cutting wheel 20A according to a first modification. In this cutting wheel 20A, the first mounting hole 41 of the first substrate 40 and the second mounting hole 51 of the second substrate 50 are formed with the same diameter in the mounting hole 32. In addition, the edge of the second substrate 50 that forms the second mounting hole 51 is formed with multiple (12 in the illustrated example) through-holes 57 for supplying coolant.

[0033] The hole edge portions of the first substrate 40 and the second substrate 50 are formed thin so that their inner surfaces are flush with the groove bottoms of the first flow path grooves 43 and the second flow path grooves 53. As a result, an annular intra-substrate reservoir 58 is formed on the inner surface of each of the hole edges, facing the inlet 35a of the coolant flow path 35. In other words, the intra-substrate reservoir 58 is formed in the hole forming portion of the mounting hole 32.

[0034] In this modified example, the coolant flows mainly through multiple through holes 57 into an internal substrate reservoir 58 between the first substrate 40 and the second substrate 50, and is supplied from this annular internal substrate reservoir 58 to each coolant flow path 35 via the inlet 35a.

[0035] 5 shows the structure of a cutting wheel 20B according to a second modification. Unlike the first modification, this cutting wheel 20B does not have a through hole 57, but only has an internal substrate reservoir 58. In this case, too, the internal substrate reservoir 58 is formed in the hole formation portion of the mounting hole 32. Therefore, in this modification, the coolant flows into the internal substrate reservoir 58 from the inner end of the mounting hole 32, and is supplied from this internal substrate reservoir 58 to each coolant flow path 35 via the inlet 35a.

[0036] The structure around the mounting hole 32 of the cutting wheels 20, 20A, 20B described above can also be applied to a three-ply cutting wheel, although this is not shown in the figures. That is, even in the case of a three-ply cutting wheel in which a flow path substrate forming the coolant flow path 35 is sandwiched between the first substrate 40 and the second substrate 50, it is preferable to configure the annular step 32a, the through hole 57, the substrate internal reservoir 58, etc., in consideration of the flow of coolant.

[0037] These cutting wheels 20, 20A, and 20B are detachably mounted on the drive shaft 11 via the mounting structure 15 of this embodiment in a state in which a coolant can be supplied. Four types of mounting structures 15, from the first to fourth embodiments, will be described below, and all of these mounting structures 15 are compatible with the cutting wheels 20, 20A, and 20B. Here, the mounting structure 15 will be described in detail using the cutting wheel 20 as an example.

[0038] [Mounting Structure (First Embodiment)] The mounting structure 15 for the cutting wheel 20 will be described with reference to the cross-sectional view of Fig. 6 and the exploded view of Fig. 7. As shown in both figures, the mounting structure 15 includes a drive shaft 11 that protrudes from the device body 13 (disc mounting base 24) and a mounting unit 14 attached to the drive shaft 11 in a state in which the cut-off wheel 20 is sandwiched between the drive shaft 11. The drive shaft 11 has a rotation prevention cut shaft portion 11a (rotation prevention shaft portion) and a male-threaded shaft portion 11b that is coaxial with the rotation prevention cut shaft portion 11a and protrudes from the end face of the rotation prevention cut shaft portion 11a.

[0039] In contrast, the mounting unit 14 includes an inner flange 61, a lock nut 62, and a supply joint 63. In this case, the inner flange 61, the lock nut 62, the supply joint 63, and the cut-off wheel 20 are supported on the drive shaft 11, and are arranged in the following order from the device body 13 (disc mounting base 24) side: inner flange 61, cut-off wheel 20, lock nut 62, and supply joint 63 (see FIG. 6).

[0040] The inner flange 61 engages with the anti-rotation cut shaft portion 11a of the drive shaft 11 and functions to position the cut-off wheel 20 coaxially with the drive shaft 11. The lock nut 62 is threaded onto the male threaded shaft portion 11b of the drive shaft 11 to hold the cut-off wheel 20 between itself and the inner flange 61 and also functions to supply coolant to the coolant flow path 35 (annular step portion 32a) of the cut-off wheel 20. The supply joint 63 supplies coolant from a coolant supply device (not shown) to the rotating lock nut 62.

[0041] 6, 7, and 8, the inner flange 61 is integrally formed with a shaft engaging portion 71 that engages with the anti-rotation cut shaft portion 11a of the drive shaft 11, a substrate fitting portion 72 that continues from the shaft engaging portion 71 and positions the cut-off wheel 20 (blade substrate 31) coaxially with the drive shaft 11, and a clamping contact receiving portion 73 that continues from the shaft engaging portion 71 and comes into contact with the cut-off wheel 20. In addition, an insertion hole 74 is formed in the axial center of the inner flange 61, through which the male threaded shaft portion 11b of the drive shaft 11 is inserted.

[0042] A first O-ring 75 is interposed between the shaft engaging portion 71 and the male threaded shaft portion 11b so as to be positioned on the anti-rotation cut shaft portion 11a. This seals the gap between the inner flange 61 and the male threaded shaft portion 11b, preventing leakage of coolant toward the device body 13. Similarly, a second O-ring 76 is fitted in a circular groove formed between the board fitting portion 72 and the clamping contact receiving portion 73. This seals the gap between the inner flange 61 and the cutting wheel 20, preventing leakage of coolant from the clamping contact receiving portion 73.

[0043] In this way, the first O-ring 75 and the second O-ring 76 prevent the coolant from leaking out along the inner flange 61 or the male threaded shaft portion 11b toward the device body 13, effectively preventing the coolant from entering the device body 13.

[0044] In this inner flange 61, the shaft engaging portion 71 is engaged with the anti-rotation cut shaft portion 11a from above so that the male threaded shaft portion 11b passes through the insertion hole 74. In this way, the inner flange 61 is set on the drive shaft 11, and the cutting wheel 20 is seated on the clamping contact receiving portion 73 with the mounting hole 32 (first mounting hole 41) fitting into the board fitting portion 72 for the set inner flange 61.

[0045] As shown in Figures 6, 7 and 9, the lock nut 62 has a nut body 81 with a D-cut tool hook portion 81a formed on the outer periphery, a ring-shaped convex portion 82 protruding from the tip side of the nut body 81, and an annular clamping contact portion 83 formed on the base end side of the nut body 81 and clamping the cutting wheel 20 between it and the inner flange 61.

[0046] The lock nut 62 also has a coolant reservoir 84 recessed inside the clamping contact portion 83 and facing the annular step portion 32a (inlet 35a) of the cutting wheel 20, a female threaded portion 85 whose tip side is connected to the coolant reservoir 84 and which screws onto the male threaded shaft portion 11b of the drive shaft 11, two recessed flow paths 86 recessed into two locations on the female threaded portion 85, and a connecting female threaded portion 87 which is coaxially connected to the tip side of the female threaded portion 85 and into which a connecting male threaded member 92 (described later) screws onto.

[0047] In this case, the female threaded portion 85 and the connecting female threaded portion 87 are formed at the axis of the nut body 81. By threading the lock nut 62 onto the drive shaft 11 via the female threaded portion 85, the drive shaft 11, inner flange 61, cut-off wheel 20, and lock nut 62 become integrated and rotate as a single unit.

[0048] The coolant reservoir 84 faces the annular step 32a of the cut-off wheel 20 on the outside of the threaded male threaded shank 11b, and sends coolant to the coolant flow path 35 of the cut-off wheel 20. A third O-ring 88 is attached to the coolant reservoir 84 so as to contact the cut-off wheel 20. This seals the gap between the lock nut 62 and the cut-off wheel 20, preventing coolant from leaking from the clamping contact portion 83.

[0049] The female threaded portion 85 has a depth sufficient for the length of the male threaded shank 11b. That is, the base end half of the female threaded portion 85 forms a threaded region 85a for the male threaded shank 11b, and the tip end half forms a non-threaded region 85b that serves as a flow path for the coolant.

[0050] Each recessed flow passage 86 is radially recessed into the female threaded portion 85 to form a U-shaped cross section, and extends from the coolant reservoir 84 to the tip of the female threaded portion 85. The two recessed flow passages 86 are recessed into the female threaded portion 85 at positions 180° symmetrical about a point, by cutting out the threads of the female threaded portion 85. In other words, the connecting female threaded portion 87, the non-threaded region 85b of the female threaded portion 85, the two recessed flow passages 86, and the coolant reservoir 84 are connected to each other, and coolant can be supplied to the cutting wheel 20 from the supply joint 63 via the lock nut 62.

[0051] The connecting female thread portion 87, the non-threaded region 85b of the female thread-shaped portion 85, the two recessed flow paths 86, and the coolant reservoir 84 constitute the "coolant introduction mechanism" referred to in the claims, the connecting female thread portion 87, the non-threaded region 85b of the female thread-shaped portion 85, and the two recessed flow paths 86 constitute the "introduction flow path portion" referred to in the claims, and further the connecting female thread portion 87 and the non-threaded region 85b of the female thread-shaped portion 85 constitute the "communication flow path" referred to in the claims.

[0052] 6, 7, 10, and 11, the supply joint portion 63 includes a joint body 91 (see FIG. 10) and a connecting male screw member 92 (see FIG. 11) that connects the joint body 91 to the lock nut 62. In this case, the connecting male screw member 92 rotates together with the drive shaft 11, constituting the "axial rotating portion" as defined in the claims, while the joint body 91 does not rotate, constituting the "non-rotating member portion" as defined in the claims.

[0053] The connecting male thread member 92 is inserted (penetrates) through the joint body 91 and is threadedly engaged with the connecting female thread portion 87 of the lock nut 62. A fourth O-ring 93 is interposed between the lock nut 62 and the joint body 91, and a fifth O-ring 94 and a spacer ring 95 are interposed between the joint body 91 and the head portion 101 of the connecting male thread member 92.

[0054] As a result, the joint body 91 seals the coolant being supplied between it and the lock nut 62, and in this state allows the lock nut 62 to rotate. That is, a coolant supply device is connected to the joint body 91 via the liquid supply tube 21, and the supply joint 63 supplies coolant to the rotating lock nut 62.

[0055] The connecting male screw member 92 has a head portion 101 and a shaft portion 102, and a male screw 102a is formed at the tip of the shaft portion 102 to screw into the connecting female screw portion 87 of the lock nut 62. A bottomed axial hole 103, which serves as a flow path for the coolant, is drilled at the axial center of the shaft portion 102 from the male screw 102a side. Furthermore, a radial hole 104 is formed in the middle portion of the shaft portion 102, penetrating radially and communicating with the axial hole 103. The axial hole 103 and the radial hole 104 form an axial flow path 105 for the coolant.

[0056] When the connecting male screw member 92 is screwed into the connecting female screw portion 87 of the lock nut 62, the space between the joint body 91 and the lock nut 62 and the space between the joint body 91 and the head 101 of the connecting male screw member 92 are sealed, and the axial flow path 105 (axial hole 103) and the connecting female screw portion 87 are connected.

[0057] The joint body 91 is integrally formed with a rotation-permitting portion 111 through which the connecting male screw member 92 is inserted, and a tube connection portion 112 (connection port portion) to which the liquid supply tube 21 is connected. The rotation-permitting portion 111 is formed with a first seal receiving hole 113 into which the above-mentioned fourth O-ring 93 is attached, and a second seal receiving hole 114 into which the fifth O-ring 94 and spacer ring 95 are attached.

[0058] Furthermore, the rotation-permitting portion 111 is formed with a loose-fitting hole 116 located between the first seal receiving hole 113 and the second seal receiving hole 114, and which forms an annular liquid reservoir 115 for coolant between the inserted connecting male screw member 92 (shaft portion 102). This allows the annular liquid reservoir 115 of the joint body 91 to communicate with the axial hole 103 of the connecting male screw member 92 via the radial hole 104 of the connecting male screw member 92. In other words, coolant in the annular liquid reservoir 115 can always be supplied to the connecting male screw member 92, which rotates integrally with the lock nut 62.

[0059] The tube connection portion 112 is formed with a tapered female thread 117 into which the coupler of the liquid supply tube 21 is threadedly engaged. By connecting the liquid supply tube 21 to this tapered female thread 117, it becomes possible to supply the liquid coolant from the liquid coolant supply device to the joint body 91.

[0060] The tip of a rotation-preventing arm 18 extending from the cover holder 17 engages with the joint body 91 (see FIG. 1), thereby preventing the joint body 91, to which the liquid supply tube 21 is connected, from rotating together with the lock nut 62.

[0061] 12 shows a device structure 15A for a cut-off wheel 20 according to a second embodiment. In this mounting structure 15A, instead of the two recessed channels 86, an annular groove 121 and two straight grooves 122 are formed in the male threaded shank 11b. The annular groove 121 is formed by carving an annular shape into the middle of the male threaded shank 11b in the longitudinal direction. The mounting hole 32 of the cut-off wheel 20 faces the annular groove 121 in the radial direction, and the entire outer circumferential surface of the annular groove 121 communicates with the coolant reservoir 84, forming part of the coolant reservoir 84.

[0062] The two linear groove channels 122 are provided at 180° point-symmetric positions in the circumferential direction of the male threaded shaft portion 11b, and are engraved to the same depth as the annular groove channel 121. Each linear groove channel 122 extends perpendicularly from the annular groove channel 121 and extends to the tip of the male threaded shaft portion 11b.

[0063] As a result, the upstream side of the straight groove flow passage 122 communicates with the non-threaded region 85b, and the downstream side of the annular groove flow passage 121 communicates with the coolant reservoir 84. The coolant that flows from the axial flow passage 105 (axial hole 103) of the shaft portion 102 into the non-threaded region 85b of the lock nut 62 passes through the two straight groove flow passages 122 and the annular groove flow passage 121 to reach the coolant reservoir 84, and is then supplied from the coolant reservoir 84 to the cutting wheel 20 (annular step portion 32a).

[0064] In this case, the connecting female thread portion 87, the non-threaded region 85b of the female thread-shaped portion 85, the two straight groove channels 122, the annular groove channel 121, and the coolant reservoir 84 constitute the "coolant introduction mechanism" referred to in the claims, the connecting female thread portion 87, the non-threaded region 85b of the female thread-shaped portion 85, the two straight groove channels 122, and the annular groove channel 121 constitute the "introduction channel portion" referred to in the claims, and further the connecting female thread portion 87 and the non-threaded region 85b of the female thread-shaped portion 85 constitute the "communication channel" referred to in the claims.

[0065] [Mounting Structure (Third Embodiment)] Figure 13 shows an apparatus structure 15B for a cutting wheel 20 according to a third embodiment. In this apparatus structure 15B, instead of the two recessed passages 86, the male threaded shank 11b is formed with a through-hole passage 124 serving as a radial hole passage and an axial hole passage 125 serving as an axial hole passage. The through-hole passage 124 is formed in the longitudinal middle of the male threaded shank 11b so as to penetrate it in the radial direction. The mounting hole 32 of the cutting wheel 20 faces the through-hole passage 124 in the radial direction, and both ends of the through-hole passage 124 are connected to the coolant reservoir 84.

[0066] The axial hole flow path 125 is drilled in the axial center of the male threaded shank 11 b, and extends at a right angle from the through hole flow path 124 and to the tip of the male threaded shank 11 b. That is, one end of the axial hole flow path 125 communicates with the middle part of the through hole flow path 124, and the other end opens to the non-threaded region 85 b of the female threaded portion 85.

[0067] As a result, the upstream side of the axial hole flow path 125 communicates with the non-threaded region 85b, and the downstream side of the through-hole flow path 124 communicates with the coolant reservoir 84. The coolant that flows from the axial hole flow path 105 (axial hole 103) of the shaft portion 102 into the non-threaded region 85b of the lock nut 62 passes through the axial hole flow path 125 and the through-hole flow path 124, reaches the coolant reservoir 84, and is supplied from the coolant reservoir 84 to the cutting wheel 20 (annular step portion 32a).

[0068] In this case, the connecting female thread portion 87, the non-threaded region 85b of the female thread-shaped portion 85, the axial hole flow path 125, the through hole flow path 124, and the coolant reservoir 84 constitute the "coolant introduction mechanism" referred to in the claims, the connecting female thread portion 87, the non-threaded region 85b of the female thread-shaped portion 85, the axial hole flow path 125, and the through hole flow path 124 constitute the "introduction flow path portion" referred to in the claims, and further the connecting female thread portion 87 and the non-threaded region 85b of the female thread-shaped portion 85 constitute the "communication flow path" referred to in the claims.

[0069] 14 shows an apparatus structure 15C for a cut-off wheel 20 according to a fourth embodiment. In this mounting structure 15C, the drive shaft 11 penetrates the apparatus body 13 and extends to the side opposite the cut-off wheel 20, and the supply joint 63 is attached to the extension shaft portion 11c of the drive shaft 11. That is, the extension shaft portion 11c is connected to the base end of the male-threaded shaft portion 11b and penetrates the apparatus body 13, with the supply joint 63 attached to its tip. Although not shown, a rotation-stop member replacing the rotation-stop arm 18 engages with the supply joint 63.

[0070] A power transmission gear train x, a pair of bearings y, two spacer collars z, etc. are provided inside the device body 13 through which the extension shaft 11c (drive shaft 11) passes, and the rotational power of the motor 12 is transmitted to the drive shaft 11 via the power transmission gear train x. A shaft female thread portion 127 corresponding to the above-mentioned connecting female thread portion 87 is formed at the end of the extension shaft 11c, and a connecting male thread member 92 to which a joint main body 91 is attached is screwed into this shaft female thread portion 127.

[0071] On the other hand, a through-hole flow path 124 is formed in the male threaded shank 11b, while an extended axial hole flow path 128 corresponding to the axial hole flow path 125 is formed in the extended shank 11c. The extended axial hole flow path 128 extends at a right angle from the through-hole flow path 124 and extends to the female shank thread portion 127 of the extended shank 11c.

[0072] As a result, the upstream side of the extended axial hole flow path 128 communicates with the axial flow path 105 (axial hole 103) of the connecting male thread member 92 via the shank female thread portion 127, and the downstream side of the through hole flow path 124 communicates with the coolant reservoir 84. The coolant that flows from the axial flow path 105 into the shank female thread portion 127 passes through the extended axial hole flow path 128 and the through hole flow path 124 and reaches the coolant reservoir 84, and is supplied from the coolant reservoir 84 to the cutting wheel 20 (annular step portion 32a).

[0073] In this case, the "coolant introduction mechanism" as referred to in the claims is constituted by the female threaded portion 127 of the shaft, the extended axial hole flow path 128, the through-hole flow path 124, and the coolant reservoir 84, the "introduction flow path portion" as referred to in the claims is constituted by the female threaded portion 127 of the shaft, the extended axial hole flow path 128, and the through-hole flow path 124, and further the "communication flow path" as referred to in the claims is constituted by the female threaded portion 127 of the shaft.

[0074] As described above, according to this embodiment, the cutting wheels 20, 20A, 20B are attached to the drive shaft 11 of the cutting device 10 via the device structures 15, 15A, 15B, 15C (mounting units 14), so that the cutting wheels 20, 20A, 20B having the coolant flow paths 35 can be detachably and properly attached. That is, the cutting wheels 20, 20A, 20B can be detachably attached to the drive shaft 11 via the device structures 15, 15A, 15B, 15C in a state in which a stable supply of coolant is possible.

[0075] 10...Cutting device, 11...Drive shaft, 11a...Antibial cut shaft portion, 11b...Male threaded shaft portion, 11c...Extension shaft portion, 13...Device body, 14...Mounting unit, 15, 15A, 15B, 15C...Mounting structure, 20, 20A, 20B...Cutting wheel, 32...Mounting hole, 32a...Annular step portion, 35...Coolant flow path, 35a...Inlet, 40...First substrate, 41...First mounting hole, 50...Second substrate, 51...Second mounting hole, 57...Through hole, 58...Substrate internal reservoir portion, 61...Inner flange, 62...Lock nut, 63...Supply joint portion, 73...Clamping contact receiver portion, 74...insertion hole, 75...first O-ring, 76...second O-ring, 81...nut body, 83...clamping contact portion, 84...coolant reservoir, 85...female thread portion, 85b...non-threaded region, 86...recessed passage, 87...connecting female thread portion, 88...third O-ring, 91...joint body, 92...connecting male thread member, 93...fourth O-ring, 94...fifth O-ring, 111...rotation allowing portion, 115...annular reservoir, 121...annular groove passage, 122...straight passage, 124...through hole passage, 125...axial hole passage, 127...shaft female thread portion, 128...extended axial hole passage,

Claims

1. A cutting wheel mounting structure capable of supplying coolant to a cutting wheel having an inlet of a coolant flow path formed in a hole forming portion of a mounting hole when the cutting wheel is rotated, comprising: a drive shaft consisting of a rotation-stopping shaft portion provided on the device body side and a male threaded shaft portion protruding from the rotation-stopping shaft portion, and rotating the mounted cutting wheel; an inner flange that engages with the rotation-stopping shaft portion and receives the cutting wheel mounted on the male threaded shaft portion; a lock nut having a female threaded portion that screws into the male threaded shaft portion and clamping and fixing the cutting wheel between the lock nut and the inner flange; a coolant introduction mechanism that is formed on at least one of the drive shaft and the lock nut with the lock nut screwed onto the drive shaft, and that introduces coolant supplied from a coolant supply source to the inlet; and a supply joint portion that is coaxial with the drive shaft and has an axial rotating portion that is flow-connected to the coolant introduction mechanism and a non-rotating member portion that is flow-connected to the coolant supply source. a cutting wheel mounting structure, characterized in that the axial rotating part has an axial flow path communicating with the cooling liquid introduction mechanism, and the non-rotating member part has an annular liquid reservoir surrounding the axial rotating part and communicating with the axial flow path from a radial direction, and a connection port part communicating with the annular liquid reservoir and to which the cooling liquid supply source is connected.

2. The cutting wheel mounting structure described in claim 1, characterized in that the cooling liquid introduction mechanism has an annular cooling liquid reservoir configured between the lock nut and the cutting wheel so that the inlet faces the annular cooling liquid reservoir, and an introduction flow path portion whose upstream side communicates with the axial flow path and whose downstream side communicates with the cooling liquid reservoir.

3. The cutting wheel mounting structure described in claim 2, characterized in that the inlet flow passage portion has a recessed flow passage formed in the inner surface of the female threaded portion and extending axially from the cooling liquid reservoir along the female threaded portion, and a communication flow passage communicating the recessed flow passage with the axial flow passage.

4. The mounting structure for a cutting wheel as described in claim 2, characterized in that the inlet flow passage portion has: an annular groove flow passage formed on the outer peripheral surface of the male threaded shaft portion so as to face the cooling liquid reservoir; a straight groove flow passage formed on the outer peripheral surface of the male threaded shaft portion and extending from the annular groove flow passage to the tip of the male threaded shaft portion; and a communication flow passage connecting the straight groove flow passage and the axial flow passage.

5. The mounting structure for a cutting wheel as described in claim 2, characterized in that the inlet flow passage portion has: a radial hole flow passage formed on the outer peripheral surface of the male threaded shaft portion so as to face the cooling liquid reservoir; an axial hole flow passage formed in the axial center portion of the male threaded shaft portion and extending from the radial hole flow passage to the tip of the male threaded shaft portion; and a communication flow passage connecting the axial hole flow passage and the axial center flow passage.

6. The mounting structure for a cutting wheel as described in claim 2, characterized in that the drive shaft has an extension shaft portion that is connected to the base end side of the male threaded shaft portion and extends through the device body to the opposite side, and the supply joint portion is attached to the extension shaft portion, and the introduction flow passage portion has: a radial hole flow passage formed on the outer circumferential surface of the male threaded shaft portion so as to face the cooling liquid reservoir, an extended axial hole flow passage formed in the axial portion of the male threaded shaft portion and the extension shaft portion and extending from the radial hole flow passage to the tip of the extension shaft portion, and a communication flow passage communicating between the extended axial hole flow passage and the axial flow passage.

7. The cutting wheel mounting structure described in claim 1, characterized in that the inner flange has a first seal member that seals between it and the cutting wheel, and a second seal member that seals between it and the male threaded shaft portion.

8. The cutting wheel mounting structure according to claim 1, characterized in that the lock nut has a third seal member for sealing between the lock nut and the cutting wheel.

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