JP2010142929A - Cutter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a space on a wall part side farther from at least a saw blade out of opposing wall parts of a gear box. <P>SOLUTION: In a circular saw 1 in which the rotational torque of a motor is transmitted to a saw blade 29 via an initial gear 13, an intermediate gear 25 and a terminating gear 21 to rotate a saw blade 29, a through-hole 25a penetrating along the center axis of rotation is formed in the intermediate gear 25. An intermediate shaft 23 having the intermediate gear 25 is inserted in the through-hole 25a, and both ends thereof are respectively fixed to opposing wall parts 5a, 5b of a gear box 5. A radial ball bearing 27 is interposed between an inner circumferential surface of the through-hole 25a and an outer circumferential surface of the intermediate shaft 23. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a cutting machine such as a portable circular saw, and more particularly to measures for reducing the space of a gear box.

The present applicant has developed a cutting machine as disclosed in Patent Document 1. In this cutting machine, an intermediate gear that meshes with a start gear provided on a motor shaft and a terminal gear provided on a saw blade shaft is provided on an intermediate shaft, and both ends of the intermediate shaft are bearing on opposing wall portions of a gear box. It is supported so that it can rotate freely. Of the bearings at both ends of the intermediate shaft, the bearing closer to the saw blade is a radial ball bearing, but the bearing far from the saw blade is a needle bearing that requires less space than the radial ball bearing. In order to reduce the space of the gear box.
JP 2007-210063 (paragraph 0029 column to paragraph 0032 column, FIG. 6)

  However, although the needle bearing is designed to reduce the space of the gear box, a radial ball bearing is used as the needle bearing is located around the end of the intermediate shaft and surrounds the end of the intermediate shaft. Therefore, it is absolutely necessary to have that much space, and it is impossible to reduce the space of the gear box any more.

  The present invention has been made in view of such points, and an object thereof is to further reduce the space on the side of the wall portion farther from the saw blade among the opposing wall portions of the gear box. .

  In order to achieve the above object, the present invention is characterized in that a support structure at least far from the saw blade of the intermediate shaft is devised.

  Specifically, the present invention provides a starting gear provided on the motor shaft, a terminal gear provided on the saw blade shaft, and an intermediate shaft between the motor shaft and the saw blade shaft, and the starting gear. And an intermediate gear meshing with the terminal gear are housed in the gear box, and are configured to transmit the rotational torque of the motor to the saw blade via the start gear, the intermediate gear, and the terminal gear to rotationally drive the saw blade. Based on the premise of a cutting machine, the following solutions were taken.

  That is, in the first aspect of the present invention, the intermediate gear is formed with a through hole penetrating along the rotation center line, and the intermediate shaft is inserted through the through hole and both ends thereof are opposed to the gear box. A bearing is interposed between the inner peripheral surface of the through hole and the outer peripheral surface of the intermediate shaft.

  According to a second aspect of the present invention, in the above premise, the intermediate shaft includes a first shaft whose one end is fixed to a wall portion far from the saw blade among the opposing wall portions of the gear box, and the intermediate gear. And a second shaft that is rotatably supported via a bearing on a wall portion closer to the saw blade of the opposing wall portion of the gear box, and is opposite to the second shaft of the intermediate gear. A recess is formed on the side, and the other end of the first shaft is inserted into the recess, and a bearing is interposed between the inner peripheral surface of the recess and the outer peripheral surface of the other end of the first shaft. It is characterized by being.

  According to the first aspect of the invention, in the process in which the rotational torque of the motor is transmitted to the saw blade, the intermediate gear is connected to the intermediate shaft around the intermediate shaft fixed at both ends to the opposing wall portion of the gear box. It rotates through a bearing interposed between them. Therefore, there are no bearings on the outer periphery of both ends of the intermediate shaft, and the opposing wall portion of the gear box can be reduced by that amount, so that the space of the gear box can be reduced as compared with Patent Document 1.

  According to the second aspect of the present invention, in the process in which the rotational torque of the motor is transmitted to the saw blade, the intermediate gear is rotated with one end side supported by the first shaft and the other end side supported by the second shaft. To do. The second shaft is rotatably supported via a bearing on a wall portion closer to the saw blade of the opposing wall of the gear box, and one end of the first shaft is out of the opposing wall of the gear box. The other end of the first shaft is fixed to the wall portion far from the saw blade, and is inserted into the concave portion of the intermediate gear, and is interposed between the inner peripheral surface of the concave portion and the other outer peripheral surface of the first shaft. The intermediate gear is rotatably supported through a mounted bearing. Therefore, there is no bearing on the outer periphery of the first shaft on the side of the gear box facing away from the saw blade among the facing walls of the gear box, and the wall portion of the facing wall of the gear box far from the saw blade is reduced accordingly. Therefore, the space of the gear box can be reduced as compared with Patent Document 1.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
1 to 4 show a portable circular saw 1 as a cutting machine. The circular saw 1 includes a housing 9 including a motor case 3, a gear box 5, and a saw cover 7.

  A handle 3a gripped by an operator is integrally projected on the upper side outside the motor case 3, and a motor (not shown) is accommodated in the motor case 3.

  Inside the gear box 5, a start end gear 13 provided integrally with the tip of the motor shaft 11 of the motor is rotatably accommodated via a radial ball bearing 15. A cooling fan 16 is connected to the motor shaft 11 near the start gear 13 so as to rotate together.

  Further, in the gear box 5, a saw blade shaft 17 is rotatably accommodated in a posture parallel to the motor shaft 11 via a radial ball bearing 19 disposed at the base end and a middle portion thereof. The saw blade shaft 17 is provided with a terminal gear 21 which is integrally rotated.

  Further, inside the gear box 5, the intermediate shaft 23 is accommodated in a posture parallel to the motor shaft 11 and the saw blade shaft 17, so that both ends of the intermediate shaft 23 are The gearbox 5 is inserted and fixed in insertion holes 5c formed in the opposing wall portions 5a and 5b.

  An intermediate gear 25 that meshes with the start gear 13 and the end gear 21 is fitted on the intermediate shaft 23. The intermediate gear 25 is formed with a through hole 25a penetrating along the rotation center line, the intermediate shaft 23 is inserted through the through hole 25a, and the through hole 25a inner peripheral surface and the intermediate shaft 23 outer peripheral surface Two radial ball bearings 27 are interposed between the two.

  At the tip of the saw blade shaft 17, a disk-like saw blade (round saw blade) 29 is integrally connected to the saw blade shaft 17 with the same rotation center, and the rotational torque of the motor is transferred to the start gear 13 and the middle. The signal is transmitted to the saw blade 29 via the gear 25 and the terminal gear 21 to rotate the saw blade 29. Then, in the process in which the rotational torque of the motor is transmitted to the saw blade 29, the intermediate gear 25 is connected to the intermediate shaft 23 around the intermediate shaft 23 whose both ends are fixed to the opposing walls 5 a and 5 b of the gear box 5. It rotates through a radial ball bearing 27 interposed therebetween.

  The saw cover 7 has a substantially U-shaped cross section and a substantially semicircular shape, and covers a substantially upper half of the outer periphery of the saw blade 29.

  A safety cover 31 having a substantially U-shaped cross-section and covering a substantially lower half of the outer periphery of the saw blade 29 is rotatably disposed inside the saw cover 7 so as to cut the workpiece. The safety cover 31 is pushed by the work material and goes around into the saw cover 7.

  A reinforcing plate 33 made of a metal material and having a U-shaped cross section is attached to the tip of the safety cover 31 on the saw blade 29 side (see FIG. 1). As shown in FIG. 5, the attachment structure has three locking holes 31 a penetrating through the front end side of the safety cover 31 at a predetermined interval, while locking pieces 33 a are formed on both side surfaces of the reinforcing plate 33. Three projections are provided at predetermined intervals so as to correspond to the locking holes 31a, and the locking pieces 33a are inserted into the locking holes 31a from both sides in a state where the front end of the safety cover 31 is wrapped with the reinforcing plate 33. The reinforcing plate 33 is attached to the front end of the safety cover 31 by being bent and inserted.

  A rectangular surface plate 35 is disposed below the housing 9. A surface plate support 37 is erected on one end of the surface plate 35, and a bracket 39 is fixed to the surface plate support 37. One end of the saw cover 7 is pivotally connected to the bracket 39 by a rotating shaft 41 (see FIG. 2), and the surface plate 35 is rotated up and down around the rotating shaft 41 to support the saw blade 29. The amount of protrusion downward of the surface plate 35, that is, the depth of cut with respect to the workpiece is adjusted.

  In FIG. 2, reference numeral 43 denotes a cutting depth adjusting mechanism that adjusts the cutting depth, and reference numeral 45 denotes a workpiece that is inclined by tilting the saw blade 29 with respect to the surface plate 35 as shown in FIG. 1. An inclination angle adjusting mechanism 47 that forms a cut surface is a parallelism adjusting mechanism for making the surface of the saw blade 29 parallel to the edge of the surface plate 35.

  As shown in FIG. 1, the cut depth adjusting mechanism 43 rises from the surface plate 35 while being bent obliquely upward, and has an arcuate guide member 49 having a guide hole 49a composed of a long hole extending almost over the entire length. The nut member 51 is engaged with the guide hole 49a of the guide member 49 so as to be movable along the guide hole 49a. A male screw member 53 that is screwed back and forth by the operation of the operation lever 55 is screwed into the nut member 51. On the saw cover 7, an alternative cutting depth display portion 57 a is displayed so that it can be switched in a plurality of stages. A saw blade rear end position display portion 57b is displayed on the side of the surface plate 35 on the saw blade 29 side. The saw blade rear end position display portion 57b is for determining the blade tip position of the rear end of the saw blade 29 at the start of cutting. A plurality of engaging recesses 49 b are formed on the upper edge of the guide member 49 according to the amount of projection of the saw blade 29 from the reference surface of the surface plate 35. The engaging recess 49b is detachably engaged with the tip of a stopper 61 that is constantly urged by a biasing means such as a spring (not shown), and the tip of the stopper 61 is connected to one end of the side of the engaging recess 49b. Alternatively, by engaging with the other end of the side portion, one of the two alternative cutting depths (large and small cutting amounts) of the cutting depth display portion 57a is easily selected. Reference numeral 59 denotes a posture holding member that holds the stopper 61 in a non-engaged state (retracted posture).

  An example of a procedure for adjusting the cutting depth of the circular saw 1 is that the male screw member 53 is first screwed out by operating the operation lever 55 to release the guide member 49 and the nut member 51 from being fixed, and then the nut member 51 is moved along the guide hole 49 a of the guide member 49. At this time, the posture holding member 59 is operated to retract the tip of the stopper 61 from the engaging recess 49b. Next, after loosening the fixing of the mounting base and the saw cover 7 by loosening the screws of the mounting base (not shown) (similar structure appears in the modified example (FIG. 6)), the mounting base is moved along the upper surface of the saw cover 7. After selecting a predetermined alternative value (for example, 9 · 13 mm) of the cut depth display portion 57a, the mounting base is fastened to the saw cover 7 by tightening the screws of the mounting base. Then, the retracted state of the stopper 61 by the attitude holding member 59 is released, the tip of the stopper 61 is engaged with the predetermined engaging recess 49b, and one of two alternative values (for example, 9 mm or 13 mm) is selected. Thereafter, the male screw member 53 is screwed by operating the operation lever 55 to fix the nut member 51 to the guide member 49.

  The circular saw 1 having the depth of cut set in this way cuts the workpiece at one depth (for example, 9 mm or 13 mm), and then fixes the guide member 49 and the nut member 51 with the operation lever 55. The guide member 49 and the nut member 51 can be fixed again by the operation lever 55 by releasing and setting the other depth (for example, 13 mm or 9 mm) by sliding the tip of the stopper 61 on the bottom surface of the engaging recess 49b. Therefore, it is possible to easily select the depth on one side and the depth on the other side.

  Further, once the cutting depth is set as described above, for example, the cutting depth is set to 9 mm on one side, the operation lever 55 is released, and the cutting depth of the circular saw 1 becomes zero. With the saw blade 29 rotated relative to the surface plate 35 as described above, the circular saw 1 is placed on the workpiece, and the position corresponding to, for example, 9 mm of the saw blade rear end position display portion 57b is set as the work start position. Match. Thereafter, the saw blade 29 is rotated with respect to the surface plate 35, and the tip of the stopper 61 moves on the guide member 49 to enter the engagement recess 49b on one side of the cut depth. Since the rear end position is indicated by the saw blade rear end position display portion 57b, the work start position can be easily selected.

  The selection of the depth of cut is described in detail in Japanese Patent Application No. 2008-94983 filed earlier by the present applicant. In this prior application, the depth of cut display 57a and the position of the trailing edge of the saw blade are displayed. The part 57b is not mentioned, and is newly added in this application.

  As described above, in the first embodiment, the intermediate gear 25 is formed with the through hole 25a penetrating along the rotation center line, the intermediate shaft 23 is inserted into the through hole 25a, and both ends are opposed to the gear box 5. Since the radial ball bearing 27 is interposed between the inner peripheral surface of the through-hole 25a and the outer peripheral surface of the intermediate shaft 23, it is fixed to the walls 5a and 5b. There are no bearings, and the opposing wall portions 5a and 5b of the gear box 5 can be reduced by that amount, and the space of the gear box 5 can be made smaller than that of Patent Document 1.

  Further, in the first embodiment, since the tip of the safety cover 31 on the saw blade 29 side is wrapped with the reinforcing plate 33, the safety cover 31 is not damaged by contact with the workpiece and the safety cover 31 is made durable. Can be improved.

  Further, in the first embodiment, the depth of cut display 57a is provided on the saw cover 7 side, and the saw blade rear end position display 57b is provided on the side of the surface plate 35 on the saw blade 29 side. The workpiece can be cut appropriately and accurately at a predetermined cutting depth simply by aligning the rear end of the saw blade 29 with the work start position from the scale of the end position display portion 57b.

-Modification-
FIG. 6 is a cross-sectional view showing a modification of the cutting depth adjusting mechanism 43 in the first embodiment. In this modification, the guide member 49 is provided with one engaging recess 49b closer to the tip.

  Further, a mounting base 63 not shown in the first embodiment is provided so as to be movable along the upper surface of the saw cover 7. A protrusion 65 is integrally formed on the upper surface of the mounting base 63, and a bulging portion 67 is integrally formed on the lower surface of the mounting base 63 corresponding to the protrusion 65. A screw 69 is inserted into the mounting base 63, and the mounting base 63 is fixed to the saw cover 7 by tightening the screw 69, while the mounting base 63 is movable along the upper surface of the saw cover 7 by loosening the screw 69. .

  Furthermore, in this modification, the shape of the stopper 61 is substantially L-shaped and is different from that of the first embodiment. The stopper 61 is rotated around a shaft 71 against an urging force of an urging means (not shown) such as a spring by operating the stopper 61 with a finger on the upper end and the protrusion 65, and has a lower end. Is engaged with and disengaged from the engaging recess 49b.

  In addition, the second embodiment is different from the first embodiment in that there is no posture holding member 59 that holds the stopper 61 in the non-engaged state (retracted posture). Except for this point, the method of adjusting the cutting depth is the same as that of the first embodiment. The description is omitted because it is similar.

(Embodiment 2)
FIG. 7 shows a gear meshing mechanism that is a power transmission mechanism of the circular saw 1 according to the second embodiment. In the second embodiment, the structure of the intermediate shaft 23 is the same as that of the first embodiment except that the structure of the intermediate shaft 23 is different from that of the first embodiment. Therefore, only different points will be described below, and the same portions are denoted by the same reference numerals. Detailed description thereof will be omitted.

  That is, the intermediate shaft 23 protrudes integrally with the intermediate shaft 25 and the first shaft 23a whose one end is fixed to the wall portion 5a far from the saw blade 29 of the opposing wall portions 5a and 5b of the gear box 5. The gear box 5 includes a second shaft 23b rotatably supported via a radial ball bearing 27 on a wall portion 5b closer to the saw blade 29 of the opposing wall portions 5a and 5b. Further, a recess 25b is formed on the intermediate gear 25 on the side opposite to the second shaft 23b, and the other end of the first shaft 23a is inserted into the recess 25b. Further, a radial ball bearing 27 is interposed between the inner peripheral surface of the recess 25b and the outer peripheral surface of the other end of the first shaft 23a. In the process in which the rotational torque of the motor is transmitted to the saw blade 29, the intermediate gear 25 rotates with one end side supported by the first shaft 23a and the other end side supported by the second shaft 23b.

  Therefore, there is no bearing on the outer periphery of the first shaft 23a on the side of the wall 5a far from the saw blade 29 among the opposing walls 5a, 5b of the gear box 5, and the corresponding walls 5a, 5b of the gear box 5 are correspondingly removed. Among them, the wall portion 5a far from the saw blade 29 can be reduced, and the space of the gear box 5 can be reduced compared to Patent Document 1.

  In the first and second embodiments, the intermediate gear 25 is an idle gear that does not have a reduction ratio. However, as in Patent Document 1, the intermediate gear 25 is used as a first gear so that the intermediate gear 25 has a reduction ratio. The first gear and the start gear 13 are meshed with the second gear and the end gear 21, respectively, and the intermediate gear 25 (first gear and second gear) is used. You may comprise so that it may decelerate.

  The present invention is useful for a cutting machine such as a portable circular saw.

FIG. 3 is a front view showing a part of the saw blade in the circular saw according to the first embodiment. FIG. 3 is a plan view illustrating a part of the circular saw according to the first embodiment. FIG. 2 is a right side view of FIG. In Embodiment 1, it is sectional drawing of the gear box corresponding to the line | wire which connects each rotation center of a motor shaft, an intermediate shaft, and a saw blade shaft. (A) is sectional drawing before attaching a reinforcement board to the front-end | tip of a safety cover, (b) is sectional drawing of the state which attached the reinforcement board to the front-end | tip of a safety cover. FIG. 6 is a cross-sectional view showing a modification of the cut depth adjusting mechanism in the first embodiment. FIG. 5 is a diagram corresponding to FIG. 4 of the second embodiment.

Explanation of symbols

1 Circular saw (cutting machine)
5 Gear box 5a, 5b Wall 11 Motor shaft 13 Start end gear 17 Saw blade shaft 21 End gear 23 Intermediate shaft 23a First shaft 23b Second shaft 25 Intermediate gear 25a Through hole 25b Recess 27 Radial ball bearing 29 Saw blade

Claims (2)

A starting gear provided on the motor shaft;
A terminal gear provided on the saw blade shaft;
An intermediate shaft provided on an intermediate shaft between the motor shaft and the saw blade shaft, and an intermediate gear meshing with the start end gear and the end gear are accommodated in a gear box;
A cutting machine configured to transmit the rotational torque of the motor to the saw blade through the start gear, the intermediate gear, and the end gear to rotationally drive the saw blade,
The intermediate gear is formed with a through hole penetrating along the rotation center line.
The intermediate shaft is inserted through the through hole and both ends are fixed to the opposing wall portion of the gear box,
A cutting machine, wherein a bearing is interposed between the inner peripheral surface of the through hole and the outer peripheral surface of the intermediate shaft. A starting gear provided on the motor shaft;
A terminal gear provided on the saw blade shaft;
An intermediate shaft provided on an intermediate shaft between the motor shaft and the saw blade shaft, and an intermediate gear meshing with the start end gear and the end gear are accommodated in a gear box;
A cutting machine configured to transmit the rotational torque of the motor to the saw blade through the start gear, the intermediate gear, and the end gear to rotationally drive the saw blade,
The intermediate shaft includes a first shaft, one end of which is fixed to a wall portion far from the saw blade of the opposing wall portion of the gear box, and a projecting integrally with the intermediate gear, the opposing wall portion of the gear box A second shaft that is rotatably supported via a bearing on the wall near the saw blade,
A recess is formed on the side opposite to the second shaft of the intermediate gear,
The other end of the first shaft is inserted into the recess,
A cutting machine, wherein a bearing is interposed between the inner peripheral surface of the recess and the outer peripheral surface of the other end of the first shaft.