JP5523766B2 - Power tools - Google Patents

Description

  The present invention relates to a power tool such as a grinder equipped with an electric motor as a drive source, a screw tightening tool, a cutting tool, or a chain saw equipped with an engine (internal combustion engine) as a drive source.

This type of power tool includes a reduction gear train for reducing (shifting) the rotational power of the drive source and a gear train for changing the output direction. A spur gear train or a planetary gear mechanism is used as the reduction gear train, and a bevel gear train (bevel gear) is used to change the output direction. Further, for example, as disclosed in Patent Document 4 below, in a rotary tool such as a screw tightening tool, the power transmission path of the reduction gear train is switched, and the output state depends on the load torque applied to the bit (tip tool). Thus, there is provided a technique for gradually switching between a high speed low torque output mode and a low speed high torque output mode.
In addition to the power tool, the rotational output speed change mechanism is configured to perform stepwise switching at low speed and high speed by switching the power transmission path of the gear train as described above, and the reduction ratio is stepless. A continuously variable transmission (CVT) that is changed at the same time is known. Conventionally, a continuously variable transmission using a so-called traction drive mechanism has been known. Techniques relating to this traction drive type continuously variable transmission are disclosed in, for example, the following Patent Documents 1 to 3.
This traction drive type continuously variable transmission presses a sun roller on the input side and a thrust roller on the output side to a plurality of conical planetary rollers with a large force using a thrust mechanism, and the rolling contact obtained thereby. Is used to transmit the power, and the speed change roller is pressed against the conical surface of the planetary roller, and the output rotation speed is changed by changing the contact diameter by displacing the pressure contact position between the small diameter side and the large diameter side. It is configured to change continuously without shifting.
Patent Document 1 discloses a screw tightening tool in which such a continuously variable transmission is incorporated. In this screw tightening tool, the output mode is steplessly changed to the low speed high torque output mode by displacing the speed change roller to the low speed side as the load torque applied to the screw tightening bit increases (progress of screw tightening). Thus, a quick and reliable screw tightening operation can be easily performed.

Japanese Unexamined Patent Publication No. 6-19740 JP 2002-59370 A Japanese Patent Publication No. 3-73411 Japanese Patent No. 3289958

Since the continuously variable transmission has an input shaft and an output shaft coaxially, the output shaft of the electric motor as a drive source and the spindle (output shaft of the power tool) on which a screw tightening bit is mounted are coaxial. The screwing machine to be arranged can be interposed relatively easily. However, many power tools have a relationship in which the output shaft of the drive source and the spindle are not coaxial. For example, the above-described disc grinder is disposed at a position where the spindle is orthogonal (crossed) to the output shaft of the electric motor. In a cutting machine such as a portable marnoco, the spindle is displaced in parallel to the output shaft of the electric motor. It is arranged at the position.
Focusing on the processing direction of the tip tool mounted on the spindle with respect to the processing target, in the case of a disc grinder, portable marnoco, or chainsaw, the output direction of the drive source is the processing direction of a circular grindstone, circular saw blade, or chain. The shaft or the output shaft of the speed reduction mechanism is disposed so as to intersect.
The present invention also uses a continuously variable transmission for a power tool in which the output shaft of the drive source and the spindle are not coaxial with each other and a power tool in which the machining direction of the tip tool intersects the output shaft of the drive source. Accordingly, it is an object of the present invention to further increase the function of quick and reliable processing of power tools in a wider range than before.

Said subject is solved by each following invention.
1st invention is a power tool provided with the traction drive type continuously variable transmission, Comprising: The separate axis | shaft which is not coaxial with the output shaft of a continuously variable transmission is made into the spindle for mounting | wearing with a tip tool. It is a power tool.
According to the first invention , the power of the drive source is decelerated by the traction drive type continuously variable transmission and output to the spindle. The spindle is not coaxial with the output shaft of the continuously variable transmission, and is arranged in parallel with being displaced by a certain distance, such as a portable marnoco, or arranged so as to intersect like a disc grinder.
In this way, not only a power tool in which the spindle is coaxially arranged with respect to the output shaft of the continuously variable transmission like a conventional screw tightening machine or a drill for drilling, but also a spindle like a disc grinder or a portable marnoco. The function and added value of a power tool that is arranged in parallel with a certain distance between axes or intersects can be further enhanced by using a traction drive type continuously variable transmission.
The configuration in which the output shaft and the spindle of the continuously variable transmission are coaxially arranged is a configuration in which the output shaft and the spindle are directly connected coaxially and rotate integrally. A case where the mechanism is interposed and the both axes rotate at different rotational speeds with the same axis as the central axis is included.
On the other hand, in the configuration in which the spindle is a separate shaft that is not coaxial with the output shaft of the continuously variable transmission, for example, a spur gear train is interposed between the two shafts, and both the shafts are parallel to and different from each other. In the case where the rotation speed is the same or different, and for example, a bevel gear train is interposed between the two axes so that the two axes intersect each other at right angles or at a certain angle. Including the case where the rotation speed is the same or different.
As described above, a traction drive type continuously variable transmission is used between the drive source and the spindle for all types of power tools with the electric motor or the internal combustion engine (engine) as the drive source. By providing, it becomes possible to output appropriate power (number of rotations and output torque) according to the machining situation, and as a result, the function and added value of a wider range of power tools than before can be increased.
A second invention is a power tool according to the first invention, wherein the spindle intersects the output shaft of the continuously variable transmission.
According to the second invention , for example, a disc grinder can be provided with the merit of the traction drive type continuously variable transmission.
A third invention is the power tool according to the first invention, wherein the spindle is arranged in parallel to the output shaft of the continuously variable transmission.
According to the third aspect of the invention , for example, a portable marnoco can be provided with the merit of the traction drive type continuously variable transmission.
According to a fourth aspect of the present invention, in any one of the first to third aspects, the power tool includes an auxiliary reduction mechanism having a fixed reduction ratio separately from the continuously variable transmission.
According to the fourth aspect of the invention , the output steplessly shifted by the continuously variable transmission is decelerated again by the reduction mechanism with a fixed reduction ratio and output to the spindle. By using a bevel gear train as a reduction mechanism with a fixed reduction ratio, the spindle can intersect the output shaft of the continuously variable transmission. Alternatively, by using a spur gear train as a reduction mechanism with a fixed reduction ratio, the spindle can be arranged in parallel to the output shaft of the continuously variable transmission with a certain inter-axis distance. Further, by using a planetary gear train as a reduction mechanism with a fixed reduction ratio, the spindle can be arranged coaxially with the output shaft of the continuously variable transmission.

In a fifth aspect based on the fourth aspect, the speed reduction mechanism is a power tool that is a gear speed reduction mechanism.
According to the fifth aspect of the invention , for example, in a portable marnoco, a traction drive type continuously variable transmission is interposed between an electric motor as a drive source and the spindle, and the spindle is connected to the output shaft of the continuously variable transmission. They can be arranged in parallel with a certain distance between the axes. In this case, the power of the drive source is steplessly shifted by the continuously variable transmission, and further decelerated by the speed reduction mechanism and output to the spindle.
In a sixth aspect based on the fourth aspect, the speed reduction mechanism is a power tool that is a belt type speed reduction mechanism.
According to the sixth invention , a traction drive type continuously variable transmission is interposed between the electric motor as a drive source and the spindle, and the spindle is fixed between the fixed shaft and the output shaft of the continuously variable transmission. They can be placed in parallel at a distance. In this case, the power of the drive source is steplessly shifted by the continuously variable transmission, and the belt is passed between pulleys with different effective diameters attached to the output shaft and spindle of the continuously variable transmission to transmit the power. It is further decelerated by the belt type reduction mechanism configured to output to the spindle.
A seventh invention is a power tool provided with a traction drive type continuously variable transmission, wherein the machining direction of the workpiece by the tip tool mounted on the spindle intersects the output shaft of the continuously variable transmission. It is a power tool.
According to the seventh invention , in addition to the case where attention is paid to the axial direction of the spindle as described above, attention is paid to the machining direction of the tip tool with respect to the workpiece, and the traction drive is used as a transmission for various power tools in the machining direction. By providing the type continuously variable transmission, the merit of the continuously variable transmission can be added to a wider range of power tools than before.
The cutting direction of the tip tool with respect to the workpiece is the tangential direction of the rotating grindstone in the case of a disc grinder, and the tangential direction of the rotating saw blade in the case of a portable marnoco or table-type circular saw. If so, it is the direction of movement of the chain, which is usually perpendicular to the spindle. Therefore, the configuration in which the machining direction intersects the output shaft of the continuously variable transmission includes a configuration in which the spindle is coaxially disposed with respect to the output shaft, and is not parallel but parallel to the output shaft. Arranged configurations or intersecting configurations are included.
An eighth invention is a power tool according to the seventh invention, in which a cutting tool or a grinding tool is mounted as a tip tool.
According to the eighth invention , when the cutting tool is mounted as the tip tool, for example, a circular rotary saw blade is mounted on the spindle of a cutting machine such as a portable marnoco, and when a grinding tool is mounted as the tip tool. Includes a case where a circular grindstone such as a disc grinder is mounted. In the case of these tip tools, the machining direction intersects or is parallel to the output shaft of the continuously variable transmission.
In a ninth aspect based on any one of the first to eighth aspects, the continuously variable transmission is a power tool whose speed reduction ratio changes in accordance with the load of the tip tool.
According to the ninth aspect, the speed reduction ratio is changed by displacing the speed change roller in the traction drive type continuously variable transmission. For this reason, by displacing the speed change roller according to the load torque applied to the tip tool, power can be output to the tip tool at an appropriate rotational speed and torque. The displacement of the speed change roller is not limited to the case where it is configured to be manually operated, and the load torque of the tip tool is detected by, for example, a sensor or the load of the drive source is detected. It can be set as the structure displaced automatically using.
A tenth aspect of the present invention is the power tool according to any one of the first to ninth aspects, wherein the continuously variable transmission is a differential planetary mechanism type.
According to the tenth aspect of the present invention , a continuously variable transmission including a so-called three-point pressure contact type traction drive mechanism in which a sun roller on an input side, a thrust roller on an output side, and a speed change roller are in pressure contact with a planetary roller is provided with By applying it to various power tools with respect to the direction or the machining direction of the tip tool, it is possible to add the advantages of this type of continuously variable transmission to a wider range of power tools than before.
In a continuously variable transmission of the differential planetary mechanism type, if the speed change roller is displaced to the large diameter side of the planetary roller, the reduction ratio increases, the output state becomes a low speed high torque output state, and if it is displaced to the small diameter side, the speed reduction ratio is increased. The output state is switched to a high-speed low-torque output state as it decreases.
In contrast, in a two-point pressure traction drive mechanism equipped with a planetary roller on the output side, if the speed change roller is displaced to the large diameter side of the planetary roller, the reduction ratio becomes smaller and the output state becomes a high-speed and low-torque output state. If it is displaced to the small diameter side, the reduction ratio is increased, and the output state is switched to the low speed high torque output state.

It is a figure which shows the schematic structure of the portable marnoco provided with the continuously variable transmission. It is a figure which shows the structure of the outline of the disc grinder provided with the continuously variable transmission. It is a side view of a three-point press-contact traction drive. 1 is an overall perspective view of a disc grinder provided with a continuously variable transmission. It is a longitudinal cross-sectional view which shows the internal structure of the disc grinder provided with the continuously variable transmission. It is a left view of an engine chain saw. FIG. 7 is a sectional view taken along line (VII)-(VII) in FIG. 6. This figure is a view of the internal structure of the engine chain saw as viewed from below. It is a longitudinal cross-sectional view which shows the internal structure of the screw fastening tool provided with the continuously variable transmission and the clutch.

Next, an embodiment of the present invention will be described with reference to FIGS. The embodiment described below is characterized by including a traction drive type continuously variable transmission for various power tools, and the traction drive type continuously variable transmission itself is well known in the art. Description is omitted.
1 and 2 show a schematic configuration of a power tool that is a hand-held power tool and includes a traction drive type continuously variable transmission 1. FIG. 1 shows a portable marnoco 10, and FIG. 2 shows a disc grinder 20.
As shown in FIG. 1, this portable marnoco 10 includes an electric motor 11 as a drive source. The continuously variable transmission 1 is connected to the output shaft of the electric motor 11. The output of the electric motor 11 is decelerated by the continuously variable transmission 1. A drive-side spur gear 13 a is attached to the output shaft 1 a of the continuously variable transmission 1. The spur gear 13b on the driven side is meshed with the spur gear 13a. The spur gear 13 b is attached to the spindle 12. The spur gears 13a and 13b constitute a reduction gear train 13 having a fixed reduction ratio. Accordingly, the rotational power decelerated by the continuously variable transmission 1 is further decelerated by the reduction gear train 13 and output to the spindle 12. A circular cutting blade (saw blade) 15 is attached to the spindle 12. Due to the reduction gear train 13, the rotation axis J <b> 1 of the spindle 12 is arranged parallel to the rotation axis J <b> 0 of the output shaft 1 a of the continuously variable transmission 1 with a certain inter-axis distance. The output shaft 1 a of the continuously variable transmission 1 is disposed coaxially with the output shaft of the electric motor 11.
As shown in FIG. 2, the disc grinder 20 includes an electric motor 21 as a drive source. The continuously variable transmission 1 is connected to the output shaft of the electric motor 21. The output of the electric motor 21 is decelerated by the continuously variable transmission 1. A drive-side bevel gear 22 a is attached to the output shaft 1 a of the continuously variable transmission 1. A bevel gear 22b on the driven side is meshed with the bevel gear 22a. The bevel gear 22 b is attached to the spindle 23. The bevel gears 22a and 22b constitute a reduction gear train 22 having a fixed reduction ratio. Accordingly, the rotational power decelerated by the continuously variable transmission 1 is further decelerated by the reduction gear train 22 and output to the spindle 23. A circular grindstone 24 is attached to the spindle 23. The rotation gear line 22 of the spindle 23 is arranged by the reduction gear train 22 so as to be orthogonal (crossed at 90 °) to the rotation axis J0 of the output shaft 1a of the continuously variable transmission 1. The output shaft 1 a of the continuously variable transmission 1 is disposed coaxially with the output shaft of the electric motor 21.
Thus, in the power tool such as the portable maroon saw 10 and the disc grinder 20, the rotation axis J1 of the spindle 12 to which the saw blade 15 as the tip tool is attached is relative to the rotation axis J0 of the output shaft 1a of the continuously variable transmission 1. When not parallel, but parallel with a certain distance between axes, or the rotation axis J2 of the spindle 23 to which the grindstone 24 is attached is not coaxial but orthogonal to the rotation axis J0 of the output shaft 1a of the continuously variable transmission 1. In each case, by providing the traction drive type continuously variable transmission 1, it becomes possible to output appropriate power (number of rotations and output torque) according to the cutting load and grinding load (processing conditions), and as a result The function and added value of a wide range of power tools can be enhanced.

FIG. 3 shows a specific internal structure of the continuously variable transmission 1. The schematic configuration will be described below. The continuously variable transmission 1 is a three-point pressure contact type continuously variable transmission, and includes an input shaft 3 connected to the drive source side, a sun roller 4 attached to the input shaft 3, and a plurality of planetary rollers having a conical shape. 5-5, a thrust roller 6 pressed against each planetary roller 5, a thrust cam mechanism 7 for generating a thrust on the thrust roller 6, an output shaft 8, and the planetary rollers 5-5 are inscribed And a speed change roller 9 pressed against the conical surface.
The plurality of planetary rollers 5 to 5 are arranged at equal intervals around the carrier 5a to be supported, and are rotatably supported. Each planetary roller 5 is supported in a direction in which its rotational axis is inclined at a certain angle from the upright position to the right side in the figure.
The sun roller 4 is in pressure contact with the pressure contact groove 5b of each planetary roller 5. The output shaft 8 is integrally provided in the thrust roller 6 so as to extend rearward (output side). A thrust cam mechanism 7 is supported on the output shaft 8.
The thrust cam mechanism 7 includes a base portion 7a that is in contact with the back side of the thrust roller 6, a pressing portion 7b that is supported so as to be relatively rotatable with respect to the base portion 7a, and to be able to approach and separate in parallel. A plurality of steel balls 7c to 7c sandwiched between the base part 7a and the pressing part 7b are provided. The pressing part 7b is urged by the compression spring 7d in a direction approaching the base part 7a side (right side in FIG. 3). The base portion 7a is pressed against the thrust roller 6 by the urging force of the compression spring 7d, whereby the sun roller 4, the thrust roller 6 and the transmission roller 9 are pressed against the planetary rollers 5 with the same pressure contact force. When each planetary roller 5 rotates about its axis in this pressure contact state, the carrier 5a rotates about the rotation axis J0 of the output shaft 8 via the pressure contact state with the speed change roller 9, and therefore the planetary rollers 5 to 5 rotate about the axis J0. The output shaft 8 is rotated.
FIG. 3 shows a no-load state. In this unloaded state, each steel ball 7c is sandwiched between the engaging recess 7e of the base portion 7a and the engaging recess 7f of the pressing portion 7b. When a rotational load is generated on the output shaft 8 from this no-load state, the pressing portion 7b is displaced in the rotational direction with respect to the base portion 7a, and the respective steel balls 7c are displaced within the engaging recesses 7e and 7f. The distance between the base portion 7a and the pressing portion 7b is increased, and the pressing force of the thrust roller 6 against each planetary roller 5 is increased. Therefore, the sun roller 4, the thrust roller 6 and the transmission roller 9 are applied to each planetary roller 5 at three points. Rotational power is transmitted to the output shaft 8 through the pressure contact state.
In this power generation state, when the speed change roller 9 is positioned on the small diameter side of the planetary roller 5, high speed and low torque is output. When the speed change roller 9 is displaced to the larger diameter side of the planetary roller 5, a low speed and high torque is output from the output shaft 8. The shift roller 9 is moved by manual operation by the user, and the load of the output shaft 8 or the load of the electric motor is detected. Based on this, the shift roller 9 is moved to the low speed side or the high speed side using an actuator. (Torque-sensitive automatic transmission mechanism).
When the load on the output shaft 8 increases to a certain value or more and the steel balls 7c to 7c are completely separated from the engaging recesses 7e and 7f, the transmission of power is cut off. When the load is returned to a certain value or less, each steel ball 7c is sandwiched between the engagement recesses 7e and 7f and returns to the power transmission state again.
As described above, the thrust cam mechanism 7 has a function as a clutch that operates based on the load of the output shaft 8 in addition to the function of generating the pressure contact force in the continuously variable transmission 1.

4 and 5 show a disc grinder 30 in which the three-point press-contact continuously variable transmission 1 is housed. In FIG. 4, the configuration of the disc grinder 30 is shown more specifically than in FIG. The disc grinder 30 includes a grip portion 31, a reduction portion 40, and a gear head portion 33 that are gripped by a user. The grip portion 31 includes an electric motor 34 as a drive source. A speed reduction portion 40 is coupled to the front portion of the grip portion 31. The continuously variable transmission 1 is built in the speed reduction unit 40. A gear head portion 33 is coupled to the front portion of the speed reduction portion 40. The gear head portion 33 is internally provided with a bevel gear train 35 having a fixed reduction ratio as an auxiliary reduction mechanism. The spindle 36 is provided so as to protrude downward from the gear head portion 33. A circular grindstone 37 is attached to the lower part of the spindle 36. A rechargeable battery pack 38 is loaded at the rear of the grip portion 31. A slide switch 32 is provided on the front side of the grip portion 31. When the slide switch 32 is slid forward, the power circuit is turned on and the electric motor 34 is activated using the battery pack 38 as a power source. The rotational power of the electric motor 34 is transmitted to the spindle 36 through the continuously variable transmission 1 of the speed reduction unit 40 and the bevel gear train 35 of the gear head unit 33. Therefore, as in the embodiment shown in FIG. 2, the rotation axis J <b> 2 of the spindle 36 is orthogonal to the rotation axis J <b> 0 of the output shaft 8 of the continuously variable transmission 1.
The speed reduction unit 40 includes a transmission case 41. The grip part 31 is attached to the rear part of the transmission case 41, and the gear head part 33 is attached to the front part. The continuously variable transmission 1 is built in the transmission case 41. An output shaft 34 a of the electric motor 34 is coupled to the input shaft 3 of the continuously variable transmission 1. The output shaft 34a of the electric motor 34 is fixed to the input shaft 3 with respect to rotation. The input shaft 3 is supported by a bearing 42 so as to be rotatable around an axis J0.
The rear side of the output shaft 8 of the continuously variable transmission 1 is rotatably supported by a bearing 43 attached to the front surface of the sun roller 4. The front portion of the output shaft 8 is rotatably supported by a bearing 44 attached to the transmission case 41. On this output shaft 8, a carrier 5a, a thrust roller 6, and a thrust cam mechanism 7 are supported. With respect to the output shaft 8, the carrier 5a and the thrust roller 6 are rotatably supported. The pressing portion 7b of the thrust cam mechanism 7 is engaged with the output shaft 8 for rotation. The base portion 7 a of the thrust cam mechanism 7 is engaged with the thrust roller 6 for rotation.

A holder 50 is attached to a part of the transmission roller 9 in the circumferential direction. The holder 50 includes two wall portions 50a and 50a that are parallel to each other, and the speed change roller 9 is inserted between the wall portions 50a and 50a in a state that allows rotation around the axis line J0.
The holder 50 is supported by a slide bar 52 supported by the transmission case 41 so as to be movable in a certain range in the front-rear direction. A compression spring 53 is interposed between the slide bar 52 and between the transmission case 41 and the front surface of the holder 50. The holder 50 is urged by the compression spring 53 in the direction of sliding backward. When the holder 50 slides to the rear side, the speed change roller 9 is displaced to the smaller diameter side of each planetary roller 5, so that the continuously variable transmission 1 is shifted to the high speed side (initial position). When the holder 50 slides against the compression spring 53 to the front side, the speed change roller 9 is displaced to the larger diameter side of each planetary roller 5, so that the continuously variable transmission 1 is changed to the low speed side. In this way, the speed change roller 9 moves in parallel between the small diameter side and the large diameter side of each planetary roller 5 in accordance with the parallel movement of the holder 50, so that the continuously variable transmission 1 is in a high speed, low torque output state and a low speed. The speed is continuously variable between the high torque output state.
The holder 50 moves using the transmission motor 51 as a drive source. A screw shaft 54 is attached to the output shaft of the transmission motor 51. A nut 55 is engaged with the screw shaft 54. The front end of the nut 55 is abutted against the rear surface of the holder 50. When the transmission motor 51 is started to the low speed side, the screw shaft 54 rotates and the nut 55 is displaced to the front side. When the nut 55 is displaced forward, the holder 50 is pushed forward against the compression spring 53, and the transmission roller 9 is displaced toward the low speed side. When the speed change motor 51 is started to the high speed side, the screw shaft 54 is reversely rotated and the nut 55 is returned to the rear side. When the nut 55 is returned to the rear side, the holder 50 is pushed rearward by the compression spring 53 and the transmission roller 9 is returned to the high speed side. The start and stop timing of the transmission motor 51 to the low speed side or the high speed side is a grinding resistance applied to the grindstone 37 and is based on the load of the electric motor 34. When the load of the electric motor 34 increases, the speed change motor 51 is started to the low speed side, the continuously variable transmission 1 is shifted to the low speed high torque output state, and when the load of the electric motor 34 is reduced, the speed change motor 51 starts to the high speed side. Then, the continuously variable transmission 1 is returned to the high speed and low torque output state. In this way, the continuously variable transmission 1 is automatically and continuously variable based on the load of the electric motor 34 that increases or decreases depending on the grinding resistance of the grindstone 37 (load-sensitive automatic transmission function).
A compression spring 7 d is interposed between the front portion of the output shaft 8 (in this embodiment, the bevel gear 35 a) and the pressing portion 7 b of the thrust cam mechanism 7. Due to the urging force of the compression spring 7d and the engagement state of the steel balls 7c with the engaging recesses 7e and 7f, the pressing force of the sun roller 4, the thrust roller 6 and the transmission roller 9 to the planetary rollers 5 is generated.
A bevel gear 35 a on the drive side of the speed reduction unit 33 is coupled to the output shaft 8. The drive-side bevel gear 35 a rotates integrally with the output shaft 8. The drive-side bevel gear 35a meshes with the drive-side bevel gear 35b. The driven-side bevel gear 35 b is fixed to the upper portion of the spindle 36. The spindle 36 is supported so as to be rotatable around the axis J2 via bearings 36a and 36b. The grindstone 37 is firmly fixed to the lower portion of the spindle 36 while being sandwiched between the fixing flange 37a and the fixing nut 37b. The range of the substantially half circumference on the rear side of the grindstone 37 is covered with a grindstone cover 39.
In the disc grinder 30 illustrated as described above, the thrust cam mechanism 7 that also functions as a clutch is connected in series between the continuously variable transmission 1 and the auxiliary reduction mechanism (bevel gear train 35) having a fixed reduction ratio. It is the composition arranged in .

Next, in the traction drive type continuously variable transmission 1, a lubricant for forming an oil film in the pressure contact portions of the sun roller 4, the thrust roller 6, and the transmission roller 9 with respect to the planetary rollers 5 to 5 is contained in the transmission case 41. Filled. Normally, traction oil (liquid) is used as the lubricant, but in this embodiment, traction grease having a lower fluidity and a paste (semi-solid) is used as the lubricant instead of the traction oil. ing.
This traction grease is made by adding metal soap or non-soap thickener and additives such as antioxidant, solid lubricant and rust preventive to base oil (base oil) such as synthetic oil or mineral oil. The base oil accounts for 70 to 90 percent, the thickener accounts for 10 to 20 percent, and has a high traction coefficient.
In the present embodiment, the consistency (consistency) is in the range of 265 to 475 (1/10 mm), and the consistency number of NLGI (National Luburicatiing Grease Institute) is No. 2 to No. 000. In range traction grease is used.
In the assembly process of the continuously variable transmission 1, the circumference of the sun roller 4, the entire circumference of each planetary roller 5, the lower surface thereof and the entire circumference of the pressure contact groove 5 b, the entire circumference of the thrust roller 6, and the transmission roller 9 An appropriate amount of this traction grease is applied to the entire inner circumference. Further, inside the transmission case 41, a grease reservoir 60 is provided for replenishing the traction grease to the contact portions of the sun roller 4, the thrust roller 6, and the transmission roller 9 with respect to each planetary roller 5. In the transmission case 41, a front block body 61 is attached to the front portion, and a rear block body 62 is attached to the rear portion. A space between the front block body 61 and the rear block body 62 is a grease reservoir 60. This grease reservoir 60 is filled with a sufficient amount of traction grease. As shown in the drawing, in the space between the front block body 61 and the rear block body 62, the press contact portions of the sun roller 4, the thrust roller 6 and the transmission roller 9 with respect to each planetary roller 5 are located, and the traction with respect to these press contact portions The grease is surely replenished.
The front and rear block bodies 61 and 62 may be made of felt material in addition to metal parts or synthetic resin moldings.
Further, since the grease pool 60 is partitioned by the front block body 61 and the rear block body 62, the traction grease is prevented from flowing out to the front side of the front block body 61 and from the transmission case 41 to the outside. Yes. Further, unlike the traction oil, the traction grease has low fluidity, so that the grease reservoir 60 is always held in a state of being filled regardless of the direction (posture) of the disc grinder 30.
Further, since the paste-type traction grease having low fluidity (diffusibility) is used as the traction drive lubricant, a high-grade seal is provided with respect to the transmission case 41 as in the case where liquid traction oil is enclosed. There is no need to apply functions. For this reason, since it is not necessary to attach a seal member such as an oil seal or an O-ring to the transmission case 41, the structure of the lubricant seal can be simplified, and as a result, the configuration of the continuously variable transmission 1 can be simplified. Can be achieved. Further, since there is less leakage than traction oil, which is a liquid, the maintenance period can be extended, and as a result, the maintainability of the continuously variable transmission 1 can be improved.
Further improvements can be added to the above configuration. For example, as shown by a two-dot chain line in FIG. 5, a felt material 63 having an annular shape is attached along the rear portion of the speed change roller 9, and the felt material 63 is pressed against the peripheral edge of the thrust roller 6 and the planetary roller 5. It can be set as the structure made to slidably contact a part. In addition, a felt material 64 having the same annular shape may be attached to the front side of the speed change roller 9 so as to be in sliding contact with the conical surface of each planetary roller 5. According to this configuration, since the traction grease permeates the felt materials 63 and 64 appropriately, this directly contacts the conical surface of each planetary roller 5 or the pressure contact portion between each planetary roller 5 and the thrust roller 6. Thus, these lubrications are more reliably performed.
The conical surface of each planetary roller 5 or the peripheral edge portion of the thrust roller 6 and the pressure contact portion that generates the traction force are mirror-finished, so that even if the felt members 63 and 64 are slidably contacted with each other, the wear is also caused. Does not occur substantially.
Further, since the grease reservoir 60 is formed between the felt material 63 and the front block body 61 by using the felt material 63 on the rear side, the rear block body 61 can be omitted.

Next, FIG. 6 shows an engine chain saw 70 as an example of a power tool. The engine chain saw 70 also includes the continuously variable transmission 1. This engine chain saw 70 has a great feature in that it has a traction drive type continuously variable transmission 1 as an output speed change means and a clutch 80 that transmits rotational power only in one direction. Since a known configuration is sufficient for this configuration, a detailed description thereof will be omitted. In the description of the chainsaw 70, the user is used as a reference in the left-right direction of the members and the like.
The engine chain saw 70 includes a main body 71 having a two-stroke engine (internal combustion engine) 75 as a driving source, a main handle 72 provided on the upper portion of the main body 71, and a sub handle provided on the left side of the main body 71. 73 is provided. FIG. 7 shows a detailed internal structure of the main body 71, but only main members will be described. In FIG. 7, reference numeral 75e indicates a cylinder block. A piston 75a is accommodated in the bore of the cylinder block 75e so as to be capable of reciprocating back and forth. One end of a connecting rod 75b is rotatably connected to the piston 75a. The other end side of the connecting rod 75b is rotatably connected to the crankshaft 75d. A spark plug 75c is attached to the combustion chamber side of the piston 75a. The spark of the spark plug 75c ignites in the air-fuel mixture supplied into the combustion chamber via a fuel supply path (not shown), and the piston 75a reciprocates. Rotational power is output from the crankshaft 75d by repeating processes as an internal combustion engine such as supply / exhaust and combustion in the course of two strokes of the piston 75a. The rotational power of the crankshaft 75d is transmitted to the spindle 76 through the clutch 80 and the continuously variable transmission 1. A chain sprocket 77 is attached to the spindle 76. A chain blade (not shown) is spanned between the chain sprocket 77 and the guide bar 78.
The guide bar 78 has a long flat plate shape, and one end side thereof is supported by a case portion 74 provided on the right side portion of the main body portion 71. The guide bar 78 extends forward from the case portion 74.

The clutch 80 transmits rotational power to the output shaft 81 when the rotational speed of the crankshaft 75d on the input side is equal to or higher than a certain value, and the rotational power to the output shaft 81 in the idle rotational state where the rotational speed of the crankshaft 75d is small. In this case, a conventionally known one is used. The rotation speed of the crankshaft 75d can be arbitrarily adjusted by a user operating an adjustment mechanism (throttle lever) provided separately.
The input shaft 3 and the sun roller 4 of the continuously variable transmission 1 are coupled to the output shaft 81 of the clutch 80. The continuously variable transmission 1 uses a three-point press-contact traction drive shown in FIGS. 3 and 5. The continuously variable transmission 1 includes members such as the planetary rollers 5 to 5, the thrust roller 6, the thrust cam mechanism 7, and the transmission roller 9 in addition to the sun roller 4. About these, the description is abbreviate | omitted using the same code | symbol in a figure. In addition, illustration of the compression spring 7d interposed between the output shaft 8 and the press part 7b of the thrust cam mechanism 7 is abbreviate | omitted in FIG. The chain sprocket 77 is attached to the right end portion of the output shaft 8. In the engine chain saw 70, the output shaft 8 functions as a spindle 76. The chain blade is stretched between the chain sprocket 77 and the guide bar 78. When the chain sprocket 77 rotates, the chain blade rotates along the periphery of the guide bar 78. Cutting can be performed by pressing a chain blade rotating along the guide bar 78 against a material to be cut such as a tree.
Adjustment of the throttle lever causes the output speed of the engine 75 to be above a certain level. Therefore, when the cutting resistance applied to the chain blade reaches a certain level in the power transmission state of the clutch 80, this is detected by a separate detection means. Based on this, the speed change roller 9 is automatically displaced to the low speed side by the activation of the actuator, whereby a high torque is output to the spindle 76. Since the continuously variable transmission 1 is automatically shifted to the high torque side based on the cutting resistance, the user can continue the cutting process as it is. The movement of the speed change roller 9 may be performed manually.
When the cutting process is completed and the cutting resistance of the chain blade is reduced, this is detected by the detecting means, and the speed change roller 9 is automatically displaced to the high speed side (initial position). In an idling state in which the output speed of the engine 75 is reduced by adjusting the throttle lever, the clutch 80 is switched to the power cut-off side, so that the transmission of the rotational power to the spindle 76 is cut off, and therefore the idling in which the rotation of the chain blade is stopped. It becomes a state. When the output speed of the engine 75 is increased by operating the throttle lever, the clutch 80 is switched to the rotational power connection state and the chain blade starts to rotate at high speed along the periphery of the guide bar 78 again.

Next, FIG. 8 shows a screw tightening tool 90 in which the three-point press-contact continuously variable transmission 1 is housed. The screw tightening tool 90 includes a main body 91 that includes an electric motor 92 as a drive source, and a handle 93 that extends laterally from the side of the main body 91. A battery pack 95 as a power source is attached to the tip of the handle portion 93. The electric motor 92 is activated using the battery pack 95 as a power source. A trigger type switch lever 96 is disposed at the base of the handle portion 93. When the switch lever 96 is pulled with a fingertip, the electric motor 92 is activated by the electric power supplied from the battery pack 95. When the electric motor 92 is activated, a screw fastening bit (only the bit socket 110 for attaching the bit is shown in the figure) attached to the front portion of the main body 91 rotates in the screw fastening direction.
The electric motor 92 is provided on the rear side of the main body housing 91 a of the main body 91. The input shaft 3 of the continuously variable transmission 1 is coupled to the output shaft 92 a of the electric motor 92. The input shaft 3 rotates integrally with the output shaft 92a. The continuously variable transmission 1 uses a three-point press-contact traction drive as in the configurations shown in FIGS. 3, 5, and 7. About each structural member of the continuously variable transmission 1, the description is abbreviate | omitted using a same code | symbol.
However, the continuously variable transmission 1 shown in FIG. 8 is provided with a shift lever 9a for manually moving the shift roller 9 (shifting). If the screw diameter to be tightened is thick, shift to the low speed side in advance, and if the screw diameter to be tightened is thin, shift the speed to the high speed side in advance and perform the screw tightening operation to secure the thick screw with a large tightening torque. The thin screw can be quickly screwed by high-speed rotation. Also in FIG. 8 as in FIG. 7, the illustration of the compression spring 7d of the thrust cam mechanism 7 is omitted.
The output shaft 8 of the continuously variable transmission 1 is disposed on the same axis (rotation axis J0) as the output shaft 92a of the electric motor 92. A spindle 100 is arranged coaxially (rotating axis J0) with respect to the output shaft 8 of the continuously variable transmission 1. A tightening torque setting mechanism 94 for setting a screw tightening torque is interposed between the output shaft 8 of the continuously variable transmission 1 and the spindle 100.

A transmission flange 97 is attached to the output shaft 8 of the continuously variable transmission 1. The transmission flange 97 is rotatably supported by the main body housing 91a via a bearing 98. The spindle 100 is disposed on the same axis (rotation axis J0) as the transmission flange 97 so as to be relatively rotatable and integrated with each other in the axial direction. The clutch plate 101 is in contact with the front surface of the transmission flange 97 with a plurality of steel balls 99 to 99 sandwiched therebetween. A compression spring 102 is interposed between the clutch plate 101 and a torque setting flange 103 provided at the front portion of the spindle 100. By this compression spring 102, the clutch plate 101 is urged in a direction to be pressed against the front surface of the transmission flange 97.
The clutch plate 101 is pressed against the transmission flange 97 with the steel balls 99 to 99 sandwiched therebetween by the urging force of the compression spring 102, whereby the rotational power of the transmission flange 97 is transmitted to the spindle 100.
One steel ball 104 is also sandwiched between the groove 101 a of the clutch plate 101 and the groove 100 a of the spindle 100. Both groove portions 101a and 100a are formed along the axis J0. Therefore, the clutch plate 101 is relatively displaced in the direction of the axis J0 while rotating integrally with the spindle 100. When a large rotational resistance (screw tightening resistance) is applied to the spindle 100, the clutch plate 101 is displaced to the front side against the compression spring 102 while relatively rotating. When the clutch plate 101 is displaced to the front side, the engagement state of the steel balls 99 to 99 is released, and the power transmission state to the transmission plate 97 is interrupted.
A bit mounting socket 110 is attached to the front portion of the spindle 100. The socket 110 is rotatably supported at the front portion of the main body case 91a via bearings 106 and 106. A window 91b for adjusting the operation setting torque is provided at the front of the main body case 91a. The window portion 91 b is disposed on the side of the torque setting flange 103. This torque setting flange 103 is screwed to the spindle 100. For this reason, when the torque setting flange 103 is rotated about the axis J0, the position in the direction of the axis J0 can be adjusted. By adjusting the position of the torque setting flange 103 in the direction of the axis J0, the urging force of the compression spring 102 can be changed to adjust the operation setting torque (the torque value at which torque transmission to the spindle 100 is interrupted). The torque setting flange 103 can be rotated by using a dedicated tool through the window portion 91b.
By appropriately setting the operation setting torque of the tightening torque setting mechanism 94, when the screw is tightened with the operation setting torque, the steel balls 99 to 99 are disengaged between the transmission flange 97 and the clutch plate 101, thereby transmitting power. Blocked.
In addition, when the setting of the tightening torque is excessive, in the thrust cam mechanism 7 of the continuously variable transmission 1, the base portion 7a is idled by the removal of the steel balls 7c to 7c. By interrupting the transmission, it is possible to prevent damage to the drive system such as the continuously variable transmission 1 or the electric motor 92. In this way, the thrust cam mechanism 7 of the continuously variable transmission 1 has a function of preventing the overload of the drive system in addition to the function of generating the pressure contact force of the sun roller 4, the thrust roller 6, and the transmission roller 9 with respect to each planetary roller 5. Has both.

According to the embodiment described above, the function and added value can be further enhanced by using the traction drive type continuously variable transmission for various types of power tools.
For example, according to the portable maroon saw 10 (power tool) shown in FIG. 1, the rotational power of the electric motor 11 as a drive source is decelerated by the continuously variable transmission 1 (three-point pressure traction drive) and the saw blade 15 is attached. Is output to the spindle 12. In this case, a reduction gear train 13 is interposed between the output shaft 1 a of the continuously variable transmission 1 and the spindle 12, and the rotational axis J 0 of the output shaft 1 a of the continuously variable transmission 1 and the rotational axis J 1 of the spindle 12. Are not coaxial but are arranged parallel to each other with a certain distance between the axes.
Thus, not only a power tool in which the spindle is coaxially arranged with respect to the output shaft of the continuously variable transmission, such as a conventional screw tightening machine or a drill for drilling, but also a reduction gear train 13 like a portable marnoco 10. The power tool in which the spindle 12 is arranged in parallel with a constant inter-axis distance is also provided with a traction drive type continuously variable transmission, so that appropriate power can be output according to the machining situation. This makes it possible to further increase the functions and added values of a wide range of power tools than before.
The same applies to the disc grinder 20 shown in FIG. 2, and a reduction gear train 22 is interposed between the output shaft 1a of the continuously variable transmission 1 and the spindle 23, so that the rotation axis J0 of the output shaft 1a and the spindle 23 are interposed. When the rotational axes J2 are orthogonal to each other (crossing), the function and added value can be further enhanced by providing the traction drive type continuously variable transmission 1.
Further, according to the portable maroon saw 10 shown in FIG. 1 and the disc grinder 20 shown in FIG. 2, the output continuously shifted by the continuously variable transmission 1 is decelerated again by the speed reduction mechanisms 13 and 20 having a fixed reduction ratio. It is output to the spindles 12 and 23. That is, as shown in FIG. 1, by using spur gear trains 13 a and 13 b as a reduction mechanism 13 with a fixed reduction ratio, the spindle 12 is spaced apart from the output shaft 1 a of the continuously variable transmission 1 by a certain distance. They can be arranged in parallel. In addition, as shown in FIG. 2, the spindle 23 can intersect the output shaft 1 a of the continuously variable transmission 1 by using bevel gear trains 22 a and 22 b as a reduction mechanism 22 with a fixed reduction ratio. Furthermore, although not shown, the spindle can be arranged coaxially with the output shaft of the continuously variable transmission by using a planetary gear train as a reduction mechanism with a fixed reduction ratio.

Thus, by adding a reduction gear train having a fixed reduction ratio to the output side of the continuously variable transmission 1, a larger reduction ratio can be set. In addition to using the illustrated reduction gear train as a reduction gear with a fixed reduction ratio added to the output side of the continuously variable transmission 1, for example, an effective attached to the output shaft 1a and the spindles 12 and 23 of the continuously variable transmission 1, respectively. A configuration may be adopted in which a belt is stretched between pulleys having different diameters so that the reduction ratio of the spindles 12 and 23 is set larger.
As described above, in addition to focusing on the axis J1 and J2 directions of the spindles 12 and 23, focusing on the machining direction of the tip tool with respect to the workpiece, a traction drive type transmission can be used as a transmission for various power tools in the machining direction. By providing the continuously variable transmission, the merit of the continuously variable transmission can be added to a wider range of power tools than before. For example, in the case of the engine chain saw 70, when the moving direction of the chain blade is a processing method for a workpiece such as a tree, a crankshaft 75d rotated by the engine 75 and a chain sprocket 77 for rotating the chain blade are attached. By interposing the continuously variable transmission 1 with the spindle 76, the moving direction of the chain blade can be made orthogonal to the rotational axis J0 of the output shaft 8. From this, the engine chain saw 70 can be quickly and surely cut in various processing situations by providing the traction drive type continuously variable transmission 1. Function and added value can be increased.

Various modifications can be made to the embodiment described above. For example, although the three-point press contact type traction drive is illustrated as the continuously variable transmission 1, a configuration using a two point press contact type traction drive provided with a planetary roller on the output side may be used.
The thrust cam mechanism 7 is illustrated as a means for generating the pressure contact force of the sun roller 4, the thrust roller 6 and the transmission roller 9 with respect to the planetary roller 5, but it is replaced with another form of pressure contact force generation means such as a screw shaft mechanism. Can do.
Further, as the power tools, the hand-held portable marnoco 10, the disc grinders 20 and 30, the engine chain saw 70 and the screw tightening tool 90 are illustrated, but the present invention is also applied to a power tool such as a stationary table saw. In addition, the present invention can be widely applied to power tools that use an air motor as a drive source instead of an electric motor.

1 ... Continuously variable transmission (3-point pressure traction drive)
DESCRIPTION OF SYMBOLS 1a ... Output shaft 3 ... Input shaft 4 ... Sun roller 5 ... Planetary roller 5a ... Carrier 6 ... Thrust roller 7 ... Thrust cam mechanism 7a ... Base part, 7b ... Press part, 7c ... Steel ball, 7d ... Compression spring, 7e, 7f ... engaging recess 8 ... output shaft 9 ... speed change roller J0 ... rotation axis 10 ... portable marrow 11 ... electric motor 12 ... spindle J1 ... rotation axis 13 ... reduction gear train, 13a ... spur gear (drive side), 13b ... Spur gear (driven side)
DESCRIPTION OF SYMBOLS 15 ... Saw blade 20 ... Disc grinder 21 ... Electric motor 22 ... Reduction gear train, 22a ... Bevel gear (drive side), 22b ... Bevel gear (driven side)
23 ... Spindle J2 ... Rotary axis 24 ... Grinding wheel 30 ... Disc grinder 31 ... Grip part 32 ... Slide switch 33 ... Gear head part 34 ... Electric motor 34a ... Output shaft 35 ... Bevel gear train 36 ... Spindle 37 ... Grinding wheel 40 ... Reduction part DESCRIPTION OF SYMBOLS 41 ... Transmission case 50 ... Holder, 50a ... Wall part 51 ... Transmission motor 52 ... Slide bar 53 ... Compression spring 54 ... Screw shaft 55 ... Nut 70 ... Engine chain saw 71 ... Main-body part 75 ... Two stroke engine (internal combustion engine)
77 ... Chain sprocket 78 ... Guide bar 80 ... Clutch (centrifugal clutch)
81 ... Output shaft 90 ... Screw tightening tool 94 ... Tightening torque setting mechanism 101 ... Clutch plate, 101a ... Groove

Claims (9)

A power tool having a traction drive type continuously variable transmission, wherein the input / output is not coaxial and the reduction ratio is fixed between the continuously variable transmission and a spindle for mounting a tip tool. An auxiliary reduction mechanism is interposed so that the spindle is a separate shaft that is not coaxial with the output shaft of the continuously variable transmission, and the load torque of the tip tool is between the auxiliary reduction mechanism and the continuously variable transmission. The power tool provided with the clutch mechanism which interrupts | blocks rotational power based on . The power tool according to claim 1, wherein the spindle intersects an output shaft of the continuously variable transmission. The power tool according to claim 1, wherein the spindle is arranged in parallel to an output shaft of the continuously variable transmission. The power tool according to claim 1, wherein the auxiliary reduction mechanism is a gear reduction mechanism. 4. The power tool according to claim 1, wherein the auxiliary reduction mechanism is a belt-type reduction mechanism. 5. A power tool having a traction drive type continuously variable transmission, wherein the input / output is not coaxial and the reduction ratio is fixed between the continuously variable transmission and a spindle for mounting a tip tool. The auxiliary speed reduction mechanism and the continuously variable transmission with the tip tool attached thereto, with the auxiliary speed reduction mechanism interposed, the machining direction of the workpiece by the tip tool intersecting the output shaft of the continuously variable transmission. A power tool provided with a clutch mechanism for cutting off rotational power based on the load torque of the tip tool. The power tool according to claim 6, wherein a cutting tool or a grinding tool is mounted as the tip tool. The power tool according to any one of claims 1 to 7, wherein the continuously variable transmission has a speed reduction ratio that changes in accordance with a load on the tip tool. The power tool according to any one of claims 1 to 8, wherein the continuously variable transmission is a differential planetary mechanism type.

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