JP2012228763A - Power tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of parts items which structure respective structures of a continuously variable transmission mechanism and an output side gear train in a power tool loaded with a traction drive type continuously variable transmission mechanism.SOLUTION: The continuously variable transmission mechanism 30 is configured to reduce the rotational drive of a motor spindle 11 by transmitting the friction due to a contact in rolling. A thrust to be required to transmit the friction in the continuously variable transmission mechanism 30 is obtained by using the thrust to be generated by the engagement of a driving gear 41 and a driven gear 45, which structure a speed reduction unit 40, in a driving state thereof. The driving gear 41 and the driven gear 45 are respectively structured of a spiral bevel gear to be engaged with each other. An intermediate transmission shaft 31 as a rotary shaft of the driving gear 41 is energized toward the continuously variable transmission 30 by the thrust generated by the engagement of the driving gear 41 and the driven gear 45 in the driving state thereof.

Description

  The present invention relates to a power tool such as a disk grinder, a screw tightening tool, or a drill for drilling, for example, equipped with an electric motor as a drive source.

  Conventionally, electric tools such as disc grinders are known as power tools. In such a power tool, the spindle is rotationally driven using an electric motor as a drive source. In addition, such a power tool incorporates a direction change gear train and a reduction gear train so that the rotational drive of the output shaft that rotates upon receiving the rotational drive of the spindle is the desired rotational drive. In other words, the direction change gear train is known to transmit the rotation of the spindle to the output shaft so that the rotation direction of the output shaft rotates in a rotation direction different from the rotation direction of the spindle. Examples of the direction changing gear train include a bevel gear train (bevel gear) and the like, and the rotational direction of the output shaft is converted to a rotational direction different from the rotational direction of the spindle. At this time, the rotation axis of the output shaft extends in a direction intersecting with the rotation axis of the spindle. Further, the reduction gear train is known to transmit the rotation of the spindle to the output shaft so that the rotation speed of the output shaft rotates at a rotation speed different from the rotation speed of the spindle. Examples of the reduction gear train include a spur gear train and a planetary gear mechanism, which convert the rotational speed of the output shaft into a rotational speed different from the rotational speed of the spindle.

By the way, a continuously variable transmission (CVT) is known as a reduction mechanism other than the above-described reduction gear train. As this continuously variable transmission mechanism, a traction drive type continuously variable transmission mechanism that is a friction transmission system by rolling contact is known (for example, see Patent Documents 1 to 3 below).
In this traction drive type continuously variable transmission mechanism, a sun roller is pressed against a plurality of conical planetary rollers supported by a holder, and the planetary roller rotates around the output shaft by using the rolling contact obtained thereby. Power is transmitted by rotation, and the output rotation speed is stepless by changing the pressure contact diameter by displacing the pressure contact position of the transmission ring pressed against the conical surface of each planetary roller between the small diameter side and the large diameter side. It is the structure which shifts by.

JP-A-6-190740 JP 2002-59370 A Japanese Patent Publication No. 3-73411

  Since the traction drive type continuously variable transmission mechanism described above is structured to decelerate by frictional transmission due to rolling contact, the frictional transmission due to rolling contact must be appropriate frictional transmission. For this reason, in such a continuously variable transmission mechanism, there is a thrust mechanism that urges these components in the contact direction in which these components are combined with each other so that the force that the components hit each other is an appropriate force. What is provided is known.

On the other hand, in the electric motor as the drive motor described above, after the speed is reduced by the continuously variable transmission mechanism, the rotation direction of the output shaft is different from the rotation direction of the spindle by the direction change gear train. May change direction. In the above-described electric motor, after the speed is reduced by the continuously variable transmission mechanism, the rotational speed of the output shaft can be converted to a rotational speed different from the rotational speed of the spindle by a further different reduction gear train. is there.
On the other hand, when these direction changing gear trains and reduction gear trains (hereinafter referred to as “output gear trains”) are provided on the output side of the continuously variable transmission mechanism, the structures of the mutual interferences. In order to avoid this, partition walls were provided between the structures. For this reason, the continuously variable transmission mechanism and the output side gear train have a separate structure, and the mutual structure can be provided without interfering with the function of each other.

  However, in the case where the continuously variable transmission mechanism and the output side gear train are arranged while providing a partition between each other so as to have a separated structure, all the components are required to form each structure. The score was bulky. For this reason, the manufacturing cost becomes expensive, or the assembling work at the time of manufacturing becomes complicated.

  The present invention has been made in view of such circumstances, and the problem to be solved by the present invention is a continuously variable transmission mechanism and an output side gear in a power tool equipped with a traction drive type continuously variable transmission mechanism. It is to reduce the number of parts constituting the mutual structure of the continuously variable transmission mechanism and the output side gear train by making the trains have a correlated structure.

In solving the above problems, the power tool according to the present invention employs the following means.
That is, the power tool according to the first aspect of the present invention is a power tool equipped with a traction drive type continuously variable transmission mechanism, and an output side of the continuously variable transmission mechanism is connected to the continuously variable transmission mechanism from the continuously variable transmission mechanism. An output side gear train that converts rotational drive into rotational drive different from the rotational drive is provided, and the mesh drive thrust generated by the meshing of the drive states of the gears constituting the output side gear train is It is used as a thrust for friction transmission in the continuously variable transmission mechanism.
Since the power tool according to the first invention is a power tool equipped with a traction drive type continuously variable transmission mechanism, it is configured to decelerate the rotational drive of the spindle by frictional transmission due to rolling contact. Here, in the continuously variable transmission mechanism, in order to maintain the frictional transmission due to the rolling contact, it is necessary to set the force with which the components hit each other to an appropriate force. That is, in the friction transmission in the continuously variable transmission mechanism, it is necessary to push the components together so that the components hit each other with an appropriate force.
Here, according to the power tool according to the first aspect of the present invention, the thrust required for friction transmission in the continuously variable transmission mechanism is the mesh drive thrust generated by the meshing of the drive states of the gears constituting the output side gear train. Therefore, the conventional separation structure for generating the thrust necessary for this friction transmission can be omitted. Thus, according to the power tool according to the first aspect of the present invention, the continuously variable transmission mechanism and the output side gear train are mutually correlated so that the continuously variable transmission mechanism and the output side gear train are in a mutually correlated structure. Can be reduced in the number of parts.

A power tool according to a second aspect of the present invention is the power tool according to the first aspect of the present invention, wherein the rotational drive from the continuously variable transmission mechanism side is provided between the continuously variable transmission mechanism and the output side gear train. An intermediate transmission shaft that inputs between the gears constituting the output side gear train is provided, and the mesh driving thrust is transmitted from the output side gear train to the continuously variable transmission mechanism via the intermediate transmission shaft. Thus, the continuously variable transmission mechanism is used as a thrust for frictional transmission.
According to the power tool of the second invention, the mesh drive thrust is transmitted from the output side gear train to the continuously variable transmission mechanism via the intermediate transmission shaft, and is used as a thrust for frictional transmission in the continuously variable transmission mechanism. Since it is used, the transmission of the mesh drive thrust to the continuously variable transmission mechanism can be simplified directly. As a result, the number of parts in configuring the structure of the continuously variable transmission mechanism can be reduced.

A power tool according to a third aspect of the invention is the power tool according to the first or second aspect of the invention, wherein the power drive thrust is separated between the continuously variable transmission mechanism and the output side gear train. The pressure regulation thrust means for generating the pressure regulation thrust that becomes the thrust of the above is provided, and the pressure regulation thrust is used as the thrust for the friction transmission in the continuously variable transmission mechanism together with the mesh drive thrust. And
According to the power tool according to the third aspect of the invention, the pressure regulation thrust is used as a thrust to be provided for friction transmission in the continuously variable transmission mechanism together with the mesh drive thrust, so that the thrust to be provided for friction transmission in the continuously variable transmission mechanism is It is possible to obtain a desired thrust obtained by adjusting the pressure regulation thrust and the mesh driving thrust. As a result, the thrust to be used for friction transmission in the continuously variable transmission mechanism can be made appropriate according to the rotational drive state of the continuously variable transmission mechanism, and the rotational drive transmission efficiency of the continuously variable transmission mechanism can be improved. it can.

A power tool according to a fourth aspect is the power tool according to the third aspect, wherein the pressure adjusting thrust means transmits the torque output from the continuously variable transmission mechanism side toward the output side gear train side. The pressure adjusting cam mechanism has a cam structure that generates the pressure adjusting thrust by the torque received from the continuously variable transmission mechanism side and the load received from the output side gear train side. It is characterized by having.
In the power tool according to the fourth aspect of the invention, the pressure adjusting thrust means is constituted by the pressure adjusting cam mechanism that transmits the torque output from the continuously variable transmission mechanism side to the output side gear train side. Further, it is possible to adopt a configuration using the rotational drive output from the continuously variable transmission mechanism, and to simplify the structure. Further, since the pressure adjusting cam mechanism has a cam structure that generates pressure adjusting thrust by the torque received from the continuously variable transmission mechanism side and the load received from the output side gear train side, the pressure adjusting thrust is reduced. The structure for obtaining can be a simple structure with a small number of members.

In the power tool according to a fifth aspect of the present invention, in the power tool according to the third or fourth aspect of the present invention, the reaction force from the continuously variable transmission mechanism side to the pressure regulation cam mechanism generated by the pressure regulation thrust is The intermediate transmission shaft is supported by a housing that rotatably supports the intermediate transmission shaft.
According to the power tool of the fifth aspect of the invention, the reaction force from the continuously variable transmission mechanism side to the pressure adjusting cam mechanism generated by the pressure adjusting thrust is supported by the housing that rotatably supports the intermediate transmission shaft. The pressure regulation thrust can be generated without interfering with the mesh driving thrust generated by the meshing of the drive states of the gears constituting the output side gear train. As a result, the pressure regulation thrust by the pressure regulation cam mechanism can be made a separate thrust completely separated from the mesh drive thrust, and the adjustment between the pressure regulation thrust and the mesh drive thrust is easy. can do.

A power tool according to a sixth invention is the power tool according to any one of the first to fifth inventions, wherein the output side gear train is one of a spiral bevel gear, a straight bevel gear, and a helical gear. It is characterized by including.
According to the power tool of the sixth aspect of the invention, the output side gear train is configured to include any one of the spiral bevel gear, the straight bevel gear, and the helical gear. The mesh drive thrust generated by the meshing of the drive states of each other can be made simple. Thereby, the structure of the power tool can be simplified, which is advantageous from the viewpoint of manufacturing cost and manufacturing work.

According to the power tool according to the first aspect of the present invention, the components that constitute the mutual structure of the continuously variable transmission mechanism and the output side gear train are configured such that the continuously variable transmission mechanism and the output side gear train are correlated. The score can be reduced.
According to the power tool of the second invention, the conventional separation structure for generating the thrust required for friction transmission can be omitted, and the number of parts in reducing the structure of the continuously variable transmission mechanism can be reduced. be able to.
With the power tool according to the third aspect of the invention, it is possible to increase the efficiency of the rotational drive transmission of the continuously variable transmission mechanism.
According to the power tool according to the fourth aspect of the present invention, when the pressure adjusting thrust means is provided, a simple configuration with a small number of members can be obtained.
According to the power tool according to the fifth aspect of the present invention, the pressure regulation thrust by the pressure regulation cam mechanism can be a separate thrust completely separated from the mesh drive thrust, and the pressure regulation thrust and the mesh drive thrust It can be easy to adjust between.
According to the power tool of the sixth aspect of the invention, the structure of the power tool can be simplified, which is advantageous from the viewpoint of manufacturing cost and manufacturing work.

1 is an overall perspective view of a disc grinder as a power tool. FIG. 2 is a top view of the disc grinder of FIG. 1 as viewed from above. It is a longitudinal cross-sectional view which shows the internal structure of a disk grinder. FIG. 4 is a cross-sectional view taken along the line (IV)-(IV) of FIG. FIG. 4 is a cross-sectional view taken along line (V)-(V) in FIG. 3, and is a cross-sectional view of an internal structure of a speed change control unit. It is a partially cutaway sectional view showing the internal structure of the speed change control unit in a top view. It is sectional drawing which expands and shows the bearing part of the front end side of an intermediate transmission shaft. It is a longitudinal cross-sectional view which shows the internal structure of the disc grinder of 2nd Embodiment. It is sectional drawing which expands and shows a pressure regulation cam mechanism. It is a perspective view of the press board which comprises a pressure regulation cam mechanism. It is sectional drawing of the press board which shows the XI-XI cross-section arrow in FIG.

[First Embodiment]
Next, a first embodiment for carrying out the power tool according to the present invention will be described with reference to FIGS. In the following, the disc grinder 1 is exemplified as a power tool according to the present invention. FIG. 1 is an overall perspective view of a disc grinder 1 as a power tool. FIG. 2 is a top view of the disc grinder 1 of FIG. 1 as viewed from above. FIG. 3 shows the internal structure of the disc grinder 1, and is a cross-sectional view showing a longitudinal section along the front-rear center line direction of the disc grinder 1 of FIG. 4 is a cross-sectional view taken along the line (IV)-(IV) in FIG. 3, and is a cross-sectional view of the internal structure of the transmission unit 3. FIG. FIG. 5 is a cross-sectional view taken along line (V)-(V) in FIG. 3 and is a cross-sectional view of the internal structure of the speed change control unit 20. FIG. 6 is a partially cutaway sectional view showing the internal structure of the speed change control unit 20 in a top view. Note that the illustrated disc grinder 1 defines up, down, front, back, left, and right as shown in the drawing for easy understanding.
As shown in FIGS. 1 and 2, the disc grinder 1 includes a tool body 2, a transmission 3, and a gear head 4 in order from the rear side. As shown in FIG. 3, an output spindle 51 is provided on the lower portion of the gear head portion 4 so as to protrude downward. The output spindle 51 corresponds to an output shaft that outputs rotational driving from the speed reduction unit 40 to the outside. A circular grindstone B is attached to the lower end portion of the output spindle 51. A grindstone cover 52 is provided on the rear side of the grindstone B in the lower portion of the gear head portion 4. The grindstone cover 52 is a cover structure of the grindstone B provided so as to cover the rear half circumference range of the grindstone B, and prevents grinding powder from being scattered by the grindstone B. In addition, the code | symbol 53 shown is a side grip for the user who hold | gripped the tool main-body part 2 with the right hand to hold | grip with the left hand.

  As shown in FIG. 3, the tool main body 2 includes a cylindrical main body case 2a having a function as a handle portion to be gripped by a user. A drive motor 10 as a drive source is housed inside the main body case 2a. The drive motor 10 is configured by a brush motor that rotationally drives the motor spindle 11. The motor spindle 11 is rotatably supported by the main body case 2a by bearings 11a and 11b. A motor cooling fan 12 is attached to the motor spindle 11. As the motor spindle 11 rotates, the fan 12 flows the outside air sucked into the main body case 2a from the rear side to the front side of the tool main body 2. The outside air flowing in this way becomes cooling air for cooling the drive motor 10. The motor spindle 11 of the drive motor 10 functions as an output shaft that is output from the drive motor 10 and also functions as an input shaft that is input to the traction drive type continuously variable transmission mechanism 30. The continuously variable transmission mechanism 30 decelerates (shifts) the rotational drive input from the motor spindle 11 and outputs it to the reduction unit 40 from the intermediate transmission shaft 31 that functions as an output shaft. In other words, the intermediate transmission shaft 31 is provided between the continuously variable transmission mechanism 30 and the speed reduction unit 40, and inputs input to gears constituting the speed reduction unit 40, which will be described in detail later, from the continuously variable transmission mechanism 30 side. Functions as an axis. Thus, the rotational driving force of the reduction unit 40 input from the intermediate transmission shaft 31 is reduced by the reduction unit 40 and output from the output spindle 51. The intermediate transmission shaft 31 and the thrust roller 34 are engaged by a key 38 so that the intermediate transmission shaft 31 rotates integrally with a thrust roller 34 described below.

The transmission unit 3 includes a transmission case 3a coupled to the front side of the main body case 2a, a traction drive type continuously variable transmission mechanism 30 installed in the transmission case 3a, and a continuously variable transmission provided in the transmission case 3a. A shift control unit 20 for controlling and controlling the mechanism 30. The transmission case 3a is a member corresponding to the housing according to the present invention, which mainly includes the continuously variable transmission mechanism 30 and the transmission control unit 20.
The rotational drive of the motor spindle 11 is decelerated (shifted) by a traction drive type continuously variable transmission mechanism 30 constituting the transmission unit 3. That is, the continuously variable transmission mechanism 30 is a three-point press-contact type continuously variable transmission mechanism, and includes a plurality (3) of sun rollers 32 attached to the motor spindle 11 of the drive motor 10 and a conical circumferential surface (conical surface 33b). ) Planetary rollers 33 to 33, a thrust roller 34 pressed against each planetary roller 33, a pressure adjusting spring 35 for generating a thrust on the thrust roller 34, and the planetary rollers 33 to 33 are inscribed. And a transmission ring 36 that is press-contacted to the conical surface 33b.
The sun roller 32 is coupled to the tip of the motor spindle 11 of the drive motor 10 and rotates integrally. The sun roller 32 is rotatably supported by the transmission case 3a via a bearing 32a. The sun roller 32 is pressed against the necks of the three planetary rollers 33 to 33. The rear side of the intermediate transmission shaft 31 that functions as an output shaft is rotatably supported via a bearing 31 a attached to the sun roller 32. The sun roller 32 and the intermediate transmission shaft 31 are disposed on the same rotation axis as the rotation axis of the motor spindle 11 of the drive motor 10. Further, as will be described in detail later, the front side of the intermediate transmission shaft 31 is rotatably supported via a bearing 31b that is slidably supported with respect to the transmission case 3a. The front portion of the intermediate transmission shaft 31 supported by the bearing 31b extends until it enters the gear head portion 4.

The three planetary rollers 33 to 33 are supported so as to be rotatable about the axis thereof via a support shaft portion 33a inserted into a support hole 37e provided at a circumferentially equally divided position (see FIG. 4) of the holder 37. . Each planetary roller 33 is supported in a direction in which the rotation axis (support shaft portion 33a) is inclined at a certain angle from the upright position (a position perpendicular to the intermediate transmission shaft 31) to the right side in the figure.
The thrust roller 34 is supported by the intermediate transmission shaft 31 so as to be capable of relative rotation and displacement in the axial direction. The thrust roller 34 is in pressure contact with the inner surface of each planetary roller 33. A boss portion 34 a provided on the rear surface of the thrust roller 34 rotatably supports a holder 37 that supports the planetary rollers 33 to 33. On the front side of the thrust roller 34, a pressure adjusting spring 35 is disposed which is a coil spring wound around the outer peripheral portion of the intermediate transmission shaft 31. The pressure adjusting spring 35 receives the rotational drive from the motor spindle 11 of the drive motor 10 and, when the continuously variable transmission mechanism 30 is initially driven, the sun roller 32, the planetary rollers 33 to 33, the thrust roller 34, the transmission ring, and the like. The thrust roller 34 is urged rearward in the drawing so that the frictional transmission necessary for the initial drive can be obtained between the thrust roller 34 and the rear side of the figure. The pressure adjusting spring 35 is mainly intended to obtain the frictional transmission required for the continuously variable transmission mechanism 30 in the initial drive of the continuously variable transmission mechanism 30, but the friction required for the continuously variable transmission mechanism 30 during driving. The purpose is also to get transmission. The pressure adjustment spring 35 is provided between the continuously variable transmission mechanism 30 and the speed reduction unit 40, and generates a pressure adjustment thrust that is a thrust different from the mesh driving thrust by the speed reduction unit 40 described later. That is, the pressure regulating spring 35 corresponds to the pressure regulating thrust means according to the present invention.
In the continuously variable transmission mechanism 30 configured as described above, the reduction ratio of the continuously variable transmission mechanism 30 with respect to the rotational drive from the motor spindle 11 is small when the transmission ring 36 is positioned on the small diameter side of the planetary rollers 33 to 33. . For this reason, the continuously variable transmission mechanism 30 rotates the intermediate transmission shaft 31 toward the output spindle 51 at a high speed. Conversely, in the state where the transmission ring 36 is positioned on the large diameter side of the planetary rollers 33 to 33, the reduction ratio of the continuously variable transmission mechanism 30 with respect to the rotational drive from the motor spindle 11 increases. For this reason, the continuously variable transmission mechanism 30 rotates the intermediate transmission shaft 31 toward the output spindle 51 at a low speed.

The transmission unit 3 includes a shift control unit 20 for shifting the continuously variable transmission mechanism 30. The transmission control unit 20 is provided on the outer periphery of the transmission ring 36 and above the transmission unit 3. As shown in FIG. 6, the transmission control unit 20 includes a transmission motor 21, a drive pulley 22 attached to the output shaft of the transmission motor 21, an operation shaft 23 arranged in parallel to the output shaft of the transmission motor 21, A driven pulley 24 attached to the shaft 23 and a drive belt 25 (see FIG. 5) spanned between the drive pulley 22 and the driven pulley 24 are provided. When the speed change motor 21 is activated, the drive belt 25 that is stretched between the drive pulley 22 and the driven pulley 24 moves to rotate the operating shaft 23 about the axis. The operating shaft 23 is provided with a screw shaft portion 23a. An operation sleeve 26 is interposed around the operation shaft 23. The screw hole portion 26 a of the operation sleeve 26 is engaged with the screw shaft portion 23 a of the operation shaft 23. When the operating shaft 23 rotates about the axis through the engagement of the screw shaft portion 23a with the screw hole portion 26a, the operating sleeve 26 moves in the axial direction (front-rear direction in the drawing) of the operating shaft 23. The operating sleeve 26 is integrally provided with a bifurcated operating arm 27 in the axial direction. The bifurcated portion of the operating arm 27 is engaged so that the outer portion of the transmission ring 36 is sandwiched from both sides in the axial direction. For this reason, when the operating sleeve 26 moves in the front-rear direction in the figure by the rotation of the operating shaft 23, the transmission ring 36 moves in parallel with the low speed side or the high speed side with the three planetary rollers 33 to 33 inscribed therein. To do.
As described above, when the speed change motor 21 is started to the high speed side, the speed change control unit 20 moves the speed change ring 36 to the high speed side (small diameter side) of the planetary rollers 33 to 33 by the rotation of the operating shaft 23. Reduce the reduction ratio. Conversely, when the speed change motor 21 is started to the low speed side, the speed change ring 36 is moved to the low speed side (large diameter side) of the planetary rollers 33 to 33 by the rotation of the operating shaft 23, thereby increasing the reduction ratio of the continuously variable transmission mechanism 30. To do. Various controls relating to starting and stopping of the drive motor 10 and the transmission motor 21 are performed by a motor control unit (not shown). Of the various controls of the motor control unit, the reduction ratio of the continuously variable transmission mechanism 30 depends on the operation input from the operation dial 28 provided on the rear side of the disc grinder 1 shown in FIG. ing.

By the way, the intermediate transmission shaft 31 constitutes an output shaft for rotational drive on the continuously variable transmission mechanism 30 side, and also functions as an input shaft for inputting rotational drive on the continuously variable transmission mechanism 30 side to the reduction unit 40. That is, the intermediate transmission shaft 31 functions as the same shaft that doubles in and out of the continuously variable transmission mechanism 30 and the speed reduction unit 40. The intermediate transmission shaft 31 is rotatably supported by a bearing 31a attached to the sun roller 32 and a bearing 31b attached to the transmission case 3a.
Here, the intermediate transmission shaft 31 is supported so as to be relatively displaceable in the axial direction of the intermediate transmission shaft 31 with respect to the bearing 31 attached to the sun roller 32. The intermediate transmission shaft 31 is supported so as to be integrally displaceable in the axial direction of the intermediate transmission shaft 31 with respect to a bearing 31b attached to the transmission case 3a. Specifically, the intermediate transmission shaft 31 is supported so that it can slide relative to the bearing 31a attached to the sun roller 32 in the front-rear direction of the drawing. The intermediate transmission shaft 31 is supported so as to be able to slide integrally with a bearing 31b attached to the transmission case 3a in the front-rear direction of the drawing.
FIG. 7 is an enlarged cross-sectional view of the bearing 31b portion on the distal end side of the intermediate transmission shaft 31. FIG. That is, the intermediate transmission shaft 31 has an inner ring so that the inner ring 31d of the bearing 31b is sandwiched between a step portion 31c provided on the outer peripheral portion of the intermediate transmission shaft 31 and a driving side gear 41 to be fitted and fixed, which will be described below. It is fixed integrally with 31d. As a result, the intermediate transmission shaft 31 can slide relative to the transmission case 3a in the front-rear direction together with the integrally fixed bearing 31b. As will be described in detail later, a sliding gap 31e is provided inside the speed change case 3a in the rear part of the bearing 31b in the drawing so that the bearing 31b can slide integrally with the intermediate transmission shaft 31 in the rear of the figure. It has been.

Next, the gear head part 4 will be described. The gear head portion 4 is disposed at the front side position of the transmission portion 3 described above. The gear head portion 4 is configured such that a speed reduction unit 40 is built in a head case 4a from which an output spindle 51 to which a grindstone B is attached can protrude downward. The head case 4a has a shape in which the inside of the speed change case 3a communicates with the inside so that the rotational driving force from the speed change unit 3 can be input to the internal reduction unit 40. Here, the intermediate transmission shaft 31 serving as the output shaft of the continuously variable transmission mechanism 30 is an input shaft for the reduction unit 40 built in the gear head portion 4.
The speed reduction unit 40 is an output side gear train according to the present invention, is provided on the output side of the continuously variable transmission mechanism 30, and converts the rotational drive from the continuously variable transmission mechanism 30 into a rotational drive different from the rotational drive. . Specifically, as shown in FIG. 3, the reduction unit 40 includes a drive side gear 41 fitted and fixed to the tip (front side in the figure) of the intermediate transmission shaft 31 that forms the input shaft of the reduction unit 40, and the reduction unit. And a driven gear 45 fitted and fixed to the base end (upper side in the figure) of the output spindle 51 forming the 40 output shaft. Reference numeral 42 denotes a front end fastener for holding the drive side gear 41 fitted and fixed to the front end (the front side in the figure) of the intermediate transmission shaft 31.
Here, the output spindle 51 is rotatably supported by bearings 51a and 51b disposed on the base end side (the upper side in the drawing) and the distal end side (the lower side in the drawing). These bearings 51a and 51b are fixed to the head case 4a.

The driving side gear 41 and the driven side gear 45 are configured by bevel gears (bevel gears). That is, the drive side gear 41 and the driven side gear 45 have a structure in which the tooth traces mesh with each other so as to transmit the rotational motion between the two axes intersecting with each other by a conical gear. Specifically, the driving side gear 41 and the driven side gear 45 are constituted by spiral bevel gears (curved bevel gears) that transmit rotational motion between two orthogonally intersecting axes. For this reason, the drive side gear 41 and the driven side gear 45 are formed with bent teeth, and the meshing at the time of rotational driving is quiet. Note that the number of teeth of the driven gear 45 is larger than the number of teeth of the drive side gear 41, and therefore when rotating motion is transmitted from the drive side gear 41 to the driven side gear 45, the rotation The movement is decelerated.
In this way, the deceleration unit 40 converts the rotational drive from the intermediate transmission shaft 31 so that the rotational drive direction of the intermediate transmission shaft 31 becomes a rotational drive direction orthogonal to the rotational drive direction, and the intermediate transmission shaft 31. The rotational drive from the intermediate transmission shaft 31 is converted so that the rotational drive speed becomes the rotational speed reduced from the rotational drive speed. Further, the rotation axis of the intermediate transmission shaft 31 input to the speed reduction unit 40 and the rotation axis of the output spindle 51 output from the speed reduction unit 40 intersect in a direction orthogonal to each other.

  When the drive side gear 41 and the driven side gear 45 are driven in mesh with each other, when the rotational movement is transmitted from the drive side gear 41 to the driven side gear 45, the drive state of the drive side gear 41 and the driven side gear 45 is changed. Engagement drive thrust is generated in the direction in which the drive side gear 41 and the driven side gear 45 are separated from each other by the engagement. Specifically, since the output spindle 51 to which the driven gear 45 is fitted and fixed is fixed to the head case 4a via bearings 51a and 51b, the drive side that works in a direction away from the driven gear 45 is driven. The meshing driving thrust of the gear 41 acts on the intermediate transmission shaft 31 to which the driving gear 41 is fitted and fixed. In this way, the intermediate transmission shaft 31 on which the mesh driving thrust acts is configured to slide integrally with the bearing 31b in a direction to fill the sliding gap 31e provided in the rear side portion of the bearing 31b in the transmission case 3a. Be energized by. Here, the intermediate transmission shaft 31 has a stepped contact portion so that the intermediate transmission shaft 31 abuts against the thrust roller 34 of the continuously variable transmission mechanism 30 when the intermediate transmission shaft 31 is urged to slide rearward in the figure. 31f is provided. The step-like contact portion 31f hits the contact portion 34b provided on the thrust roller 34 when the intermediate transmission shaft 31 is urged to slide rearward in the figure. For this reason, the intermediate transmission shaft 31 urged rearward in the drawing causes the stepped contact portion 31f of the intermediate transmission shaft 31 to hit the contact portion 34b of the thrust roller 34, and the thrust roller 34 is urged rearward in the drawing. Is done. Thus, the intermediate transmission shaft 31 moves the thrust roller 34 to the rear side in the drawing so that the necessary frictional transmission is obtained among the sun roller 32, the planetary rollers 33 to 33, the thrust roller 34, and the transmission ring 36. Energize. Accordingly, the mesh drive thrust generated by the meshing of the drive state of the drive side gear 41 and the driven side gear 45 constituting the speed reduction unit 40 is transmitted from the speed reduction unit 40 to the continuously variable transmission mechanism 30 via the intermediate transmission shaft 31. Then, it is used as a thrust for friction transmission in the continuously variable transmission mechanism 30. More specifically, the mesh driving thrust can be applied as a force for urging the intermediate transmission shaft 31 so as to move the intermediate transmission shaft 31 from the reduction unit 40 toward the continuously variable transmission mechanism 30. The spring biasing force that acts rearward on the thrust roller 34 of the pressure regulating spring 35 is a force corresponding to the pressure regulating thrust according to the present invention. Further, even with the pressure regulation thrust (spring biasing force) by the pressure regulation spring 35, as with the meshing drive thrust of the speed reduction unit 40, there is no need to obtain the friction transmission required for the continuously variable transmission mechanism 30 during driving. This is used as a thrust for friction transmission in the step transmission mechanism 30. That is, the pressure regulation thrust of the pressure regulation spring 35 is used as a thrust for frictional transmission in the continuously variable transmission mechanism 30 together with the meshing drive thrust of the speed reduction unit 40.

According to the disc grinder 1 of the first embodiment described above, the following operational effects are obtained.
That is, in the continuously variable transmission mechanism 30 described above, when each planetary roller 33 rotates around its axis by the rotation of the sun roller 32 accompanying the start of the drive motor 10 in the above-described three-point pressure contact state, the transmission ring of each planetary roller 33 is rotated. The planetary rollers 33 to 33 revolve around the intermediate transmission shaft 31 through a pressure contact state with respect to the inner surface 36. As the planetary rollers 33 to 33 supported by the holder 37 revolve around the intermediate transmission shaft 31, the thrust roller 34 rotates integrally. When the thrust roller 34 rotates, the intermediate transmission shaft 31 rotates integrally. Thus, when the drive motor 10 is activated, the rotational power is transmitted to the output spindle 51 through the continuously variable transmission mechanism 30 and the speed reduction unit 40 of the gear head unit 4 in the three-point press contact state, and the grindstone B is rotated.
Here, the traction drive type continuously variable transmission mechanism 30 is configured to decelerate the rotational drive of the motor spindle 11 by frictional transmission due to rolling contact. Here, the continuously variable transmission mechanism 30 needs to have an appropriate force for the three-point press contact in order to maintain the frictional transmission due to the rolling contact. In other words, the friction transmission in the continuously variable transmission mechanism 30 requires a thrust so as to be applied with an appropriate force for the three-point press contact.
Here, according to the disc grinder 1 described above, the thrust required for the friction transmission in the continuously variable transmission mechanism 30 is an engagement generated by the engagement of the drive state of the drive side gear 41 and the driven side gear 45 constituting the reduction unit 40. Therefore, the conventional separation structure for generating the thrust necessary for this frictional transmission can be omitted. As a result, according to the above-described disc grinder 1, the structure is correlated between the continuously variable transmission mechanism 30 and the reduction unit 40, and the number of parts constituting the mutual structure of the continuously variable transmission mechanism 30 and the reduction unit 40 is reduced. Can be reduced.
Further, according to the disc grinder 1 described above, the thrust generated by the engagement of the drive side gear 41 and the driven side gear 45 constituting the reduction unit 40 is directed from the reduction unit 40 toward the continuously variable transmission mechanism 30. It acts as a force for urging the intermediate transmission shaft 31 to slide the intermediate transmission shaft 31. That is, the mesh drive thrust is transmitted from the reduction unit 40 to the continuously variable transmission mechanism 30 via the intermediate transmission shaft 31 and used as a thrust for frictional transmission in the continuously variable transmission mechanism 30. The transmission to the continuously variable transmission mechanism 30 can be simplified directly. As a result, the number of parts in configuring the structure of the continuously variable transmission mechanism 30 can be reduced.
Further, according to the disc grinder 1 described above, the pressure regulation thrust by the pressure regulation spring 35 is used as a thrust for frictional transmission in the continuously variable transmission mechanism 30 together with the mesh drive thrust, so that the friction in the continuously variable transmission mechanism 30 The thrust used for transmission can be a desired thrust obtained by adjusting the pressure regulation thrust and the mesh driving thrust. As a result, the thrust used for friction transmission in the continuously variable transmission mechanism 30 according to the rotational drive state of the continuously variable transmission mechanism 30 can be made appropriate, and the efficiency of rotational drive transmission of the continuously variable transmission mechanism 30 can be improved. You can plan.
Further, according to the disc grinder 1 described above, the drive side gear 41 and the driven side gear 45 of the reduction unit 40 are constituted by spiral bevel gears, so that the gears constituting the reduction unit 40 are engaged in the drive state. The thrust generated by the above can be generated with a simple structure. As a result, the structure of the disc grinder 1 can be simplified, which is advantageous from the viewpoint of manufacturing cost and manufacturing work.

[Second Embodiment]
Next, a second embodiment for carrying out the power tool according to the present invention will be described with reference to FIGS. The disc grinder 6 as a power tool according to the present invention described below is compared with the disc grinder 1 of the first embodiment described above, and the pressure adjusting cam mechanism 60 (the adjustment in the first embodiment). Only the configuration relating to the structure around the pressure spring 35 is different, and the other configurations are the same. For this reason, the disc grinder 6 of the second embodiment described below focuses on the pressure regulating cam mechanism 60 that is different from the disc grinder 1 of the first embodiment, and the first embodiment. The same components as those of the disc grinder 1 of the form are denoted by the same reference numerals and the description thereof is omitted.
FIG. 8 is a longitudinal sectional view showing the internal structure of the disc grinder 6 according to the second embodiment. FIG. 9 is an enlarged sectional view showing the pressure regulating cam mechanism 60. That is, as shown in FIG. 8, in the disc grinder 6 of the second embodiment, a pressure adjusting cam mechanism 60 is provided between the continuously variable transmission mechanism 30 and the speed reduction unit 40 described above. Like the pressure adjusting spring 35 in the first embodiment, the pressure adjusting cam mechanism 60 thrusts the thrust roller 34, which is a thrust different from the mesh driving thrust by the reduction unit 40, to the rear side. The pressure regulation thrust that functions is generated. That is, the pressure adjusting cam mechanism 60 corresponds to the pressure adjusting thrust means according to the present invention, and has a function of transmitting the torque output from the continuously variable transmission mechanism 30 to the speed reduction unit 40. The torque output from the continuously variable transmission mechanism 30 includes the torque related to the rotational drive from the continuously variable transmission mechanism 30. That is, the pressure adjusting cam mechanism 60 is disposed on the front side of the thrust roller 34 and on the rear side of the speed reduction unit 40 as shown in FIG. The pressure adjusting cam mechanism 60 transmits the rotational drive output from the continuously variable transmission mechanism 30 side to the intermediate transmission shaft 31 when the rotational drive output from the continuously variable transmission mechanism 30 side is input to the speed reduction unit 40.

The pressure adjusting cam mechanism 60 is configured to transmit torque to be output from the continuously variable transmission mechanism 30 to the intermediate transmission shaft 31 by a torque received from the continuously variable transmission mechanism 30 side and a load received from the speed reduction unit 40 side. It has a cam structure that generates pressure regulation thrust. This pressure regulation thrust is a force that functions to thrust the thrust roller 34 backward for the purpose of pressure adjustment.
That is, as shown in FIG. 9, the pressure adjusting cam mechanism 60 is roughly provided with a pressing plate 61, four steel balls 62 to 62, and a thrust needle bearing 63. The pressing plate 61 is disposed on the front side of the thrust roller 34. The pressing plate 61 is supported on the front side by a thrust needle bearing 63 and on the rear side by a thrust roller 34 via four steel balls 62 to 62. That is, the four steel balls 62 to 62 are disposed between the pressing plate 61 and the thrust roller 34. Here, each of the four steel balls 62 to 62 is sandwiched with the thrust roller 34 in a state of being fitted into a cam groove 61d provided on the rear surface of the pressing plate 61 described below. The thrust needle bearing 63 is a rotation support member that supports the pressing plate 61 so as to be rotatable relative to the transmission case 3a. Reference numeral 65 denotes a steel ball holding member provided to hold the four steel balls 62 to 62 between the pressing plate 61 and the thrust roller 34.
Incidentally, a pressure adjusting spring 67 is interposed between the pressing plate 61 and the thrust roller 34. The pressure adjusting spring 67 is constituted by a compression spring whose front end is in contact with the pressing plate 61 and whose rear end is in contact with the thrust roller 34. For this reason, the pressure regulating spring 67 is supported from the pressing plate 61 and urges the thrust roller 34 toward the rear side in the drawing by the compression of the pressure regulating spring 67. The pressure adjusting spring 67 is used to allow the thrust roller 34 to obtain a frictional transmission necessary for the initial drive among the sun roller 32, the planetary rollers 33 to 33, the thrust roller 34, and the transmission ring 36. It is biased to the rear side in the figure.

FIG. 10 is a perspective view of the pressing plate 61 constituting the pressure adjusting cam mechanism 60 as viewed from the rear side. FIG. 11 is a cross-sectional view of the pressing plate 61 showing the XI-XI cross-sectional arrow in FIG.
As shown in FIG. 10, on the rear surface 61a of the pressing plate 61, four cam grooves 61d are provided at equal intervals in the circumferential direction so that each of the four steel balls 62 to 62 is fitted. As shown in FIG. 11, the cam groove 61d is formed so that its depth changes in the circumferential direction. Specifically, as shown in FIG. 11, the cam groove 61d is formed by the deepest portion 61d1 having the deepest central portion, and is formed by the inclined portion 61d2 that becomes shallower as it shifts in the circumferential direction.
In addition, the code | symbol 69 (imaginary line) in FIG. 10 and FIG. 11 shows the conventional cam groove shape. In addition, an insertion hole 61c for inserting the intermediate transmission shaft 31 is provided in the central portion of the pressing plate 61. The intermediate transmission shaft 31 is inserted into the insertion hole 61c, and the pressing plate 61 and the intermediate transmission shaft 31 are engaged by a key 64 so that the pressing plate 61 and the intermediate transmission shaft 31 rotate integrally. Are combined.

Here, the four steel balls 62 to 62 arranged between the thrust roller 34 that rotates and the pressing plate 61 to which the rotation drive is transmitted are used to adjust the torque output from the continuously variable transmission mechanism 30 to the pressure adjusting cam. When an appropriate rotational load is not generated between the thrust roller 34 and the pressing plate 61 during transmission to the intermediate transmission shaft 31 via the mechanism 60, the innermost shaft 61 is fitted into the deepest deepest portion 61d1 of the cam groove 61d. It has become a thing. On the other hand, when transmitting the rotational drive output from the continuously variable transmission mechanism 30 to the intermediate transmission shaft 31 via the pressure adjusting cam mechanism 60, an appropriate rotational load is provided between the thrust roller 34 and the pressing plate 61. In such a case, the relative positions of the thrust roller 34 and the pressing plate 61 to which the rotational drive is transmitted are displaced in the rotational direction. That is, the steel balls 62 to 62 that have been fitted in the deepest part 61d1 of the cam groove 61d until then are displaced from the deepest part 61d1 position to the inclined part 61d2 position. Then, the four steel balls 62 to 62 act so as to increase the relative distance between the pressing plate 61 and the thrust roller 34. Accordingly, the four steel balls 62 to 62 disposed between the thrust roller 34 that rotates and the pressing plate 61 to which the rotation drive is transmitted increase the pressure contact force between the pressing plate 61 and the thrust roller 34. It will be. The rotational load is a load received by the intermediate transmission shaft 31 on the speed reduction unit 40 side, which is generated in correlation with the rotational drive torque output from the continuously variable transmission mechanism 30, for example. The processing resistance at the time of processing is mentioned.
Here, since the pressing plate 61 is supported by the speed change case 3a through the thrust needle bearing 63, the pressing force of the four steel balls 62 to 62 whose pressing force is increased as described above is applied to the thrust roller 34. It acts as an external force that urges toward the rear side. As a result, the pressing force of the thrust roller 34 against each planetary roller 33 is increased, the thrust roller 34 is pressed against each planetary roller 33, and the sun roller 32 is pressed against the neck of each planetary roller 33. Each of the conical surfaces 33 b is brought into pressure contact with the transmission ring 36. The external force acting backward on the thrust roller 34 of the pressure regulating cam mechanism 60 is a force corresponding to the pressure regulating thrust according to the present invention. Further, even if there is a pressure regulation thrust by the pressure regulation cam mechanism 60 (an external force applied to the thrust roller 34 to the rear side), the friction required for the continuously variable transmission mechanism 30 during driving is the same as the meshing drive thrust of the reduction unit 40. In obtaining the transmission, it is used as a thrust for the friction transmission in the continuously variable transmission mechanism 30. That is, the pressure regulation thrust of the pressure regulation cam mechanism 60 is used as a thrust for frictional transmission in the continuously variable transmission mechanism 30 together with the meshing drive thrust of the speed reduction unit 40.

  Further, according to the disc grinder 6 of the second embodiment described above, when the drive side gear 41 and the driven side gear 45 are engaged with each other as in the disc grinder 1 of the first embodiment described above, the drive is performed. When the rotational motion is transmitted from the drive side gear 41 to the driven side gear 45, the direction in which the drive side gear 41 and the driven side gear 45 are separated from each other due to the engagement of the drive state between the drive side gear 41 and the driven side gear 45. The mesh drive thrust is generated. This meshing drive thrust acts on the intermediate transmission shaft 31 to which the drive side gear 41 is fitted and fixed. In this way, the intermediate transmission shaft 31 on which the mesh driving thrust acts is configured to slide integrally with the bearing 31b in a direction to fill the sliding gap 31e provided in the rear side portion of the bearing 31b in the transmission case 3a. Be energized by. Here, the intermediate transmission shaft 31 has a stepped contact portion so that the intermediate transmission shaft 31 abuts against the thrust roller 34 of the continuously variable transmission mechanism 30 when the intermediate transmission shaft 31 is urged to slide rearward in the figure. 31f is provided. The step-like contact portion 31f hits the contact portion 34b provided on the thrust roller 34 when the intermediate transmission shaft 31 is urged to slide rearward in the figure. For this reason, the intermediate transmission shaft 31 urged rearward in the drawing causes the stepped contact portion 31f of the intermediate transmission shaft 31 to hit the contact portion 34b of the thrust roller 34, and the thrust roller 34 is urged rearward in the drawing. Is done. Thus, the intermediate transmission shaft 31 moves the thrust roller 34 to the rear side in the drawing so that the necessary frictional transmission is obtained among the sun roller 32, the planetary rollers 33 to 33, the thrust roller 34, and the transmission ring 36. Energize. Accordingly, the mesh drive thrust generated by the meshing of the drive state of the drive side gear 41 and the driven side gear 45 constituting the speed reduction unit 40 is provided to the friction transmission in the continuously variable transmission mechanism 30 via the intermediate transmission shaft 31. Can be used as That is, the meshing drive thrust generated by the meshing of the drive state of the drive side gear 41 and the driven side gear 45 constituting the reduction unit 40 is transmitted from the reduction unit 40 to the continuously variable transmission mechanism 30 via the intermediate transmission shaft 31. Then, it is used as a thrust for friction transmission in the continuously variable transmission mechanism 30. More specifically, the mesh driving thrust can be applied as a force for urging the intermediate transmission shaft 31 so as to move the intermediate transmission shaft 31 from the reduction unit 40 toward the continuously variable transmission mechanism 30.

The thrust generated by the engagement of the drive side gear 41 and the driven side gear 45 constituting the reduction unit 40 in this way is required for friction transmission in the continuously variable transmission mechanism 30 via the intermediate transmission shaft 31. When it can be used as a powerful thrust, the following effects are also newly produced. That is, according to the disc grinder 6 of the second embodiment, the thrust for assisting the frictional transmission generated by the pressure adjusting cam mechanism 60 as described above can be set to a smaller thrust than before. Thus, the cam groove 61d provided in the pressing plate 61 can be designed to have a shorter circumferential shape as compared to the conventional cam groove shape (reference numeral 69) indicated by the phantom line in the drawing. Accordingly, when the cam groove 61d is provided in the pressing plate 61, the molding accuracy of the cam groove 61d can be lowered. Accordingly, it is possible to increase the tolerance of forming error when forming the pressing plate 61 while providing the cam groove 61d, which is advantageous in manufacturing.
Further, according to the disc grinder 6 of the above-described second embodiment, the pressure regulating thrust means according to the present invention transmits the torque output from the continuously variable transmission mechanism 30 to the intermediate transmission shaft 31. 60, the rotational drive output from the continuously variable transmission mechanism 30 can be used, and the structure can be simplified. Further, according to the disk grinder 6 described above, the reaction force from the continuously variable transmission mechanism 30 side to the pressure adjusting cam mechanism 60 generated by the pressure adjusting thrust is supported by the speed change case 3a as a housing via the thrust needle bearing 63. Will be. As a result, the pressure adjustment thrust (the external force applied to the thrust roller 34 on the rear side) can be obtained without interfering with the meshing drive thrust generated by the meshing of the drive state of the drive side gear 41 and the driven side gear 45 constituting the reduction unit 40. ) Can be generated. As a result, the pressure regulation thrust by the pressure regulation cam mechanism 60 can be made a separate thrust completely separated from the mesh drive thrust, and the adjustment between the pressure regulation thrust and the mesh drive thrust is easy. It can be.

In addition, in the power tool which concerns on this invention, it is not limited to above-described embodiment, You may make it comprise by changing a location suitably as follows.
That is, in the disc grinders 1 and 6 of the above-described embodiment, the drive side gear 41 and the driven side gear 45 are configured by spiral bevel gears as an example of the output side gear train. However, as the output side gear train according to the present invention, for example, the drive side gear 41 and the driven side gear 45 described above may be configured by straight bevel gears. Further, unlike the bevel gear, for example, the driving side gear 41 and the driven side gear 45 described above may be constituted by helical gears that are spur gears. Moreover, you may comprise including these bevel gears and a helical gear. In other words, as long as the gears constituting the gear train generate thrust by meshing in the driving state, the output side gear train according to the present invention is configured without regard to the gear shape, meshing mode, and meshing quantity. can do.
In the disk grinders 1 and 6 of the above-described embodiment, the pressure adjusting spring 35 and the pressure adjusting cam mechanism 60 are illustrated as the pressure adjusting thrust means according to the present invention. However, the pressure adjusting thrust means according to the present invention is not limited to this, and may be constituted by, for example, an appropriately electrically controlled actuator, and the engagement of the drive states of the gears constituting the output side gear train. Any mechanism may be used as long as it is provided between the continuously variable transmission mechanism and the output side gear train so as to have a thrust different from the mesh driving thrust generated by the operation.
Moreover, in above-mentioned embodiment, the disk grinder was illustrated as a power tool which concerns on this invention. However, the power tool according to the present invention is not limited to this, and may be configured by an appropriate power tool such as an appropriate screwing machine or an electric drill for drilling. Furthermore, the drive motor serving as a power drive source is not limited to an electric motor, and may be replaced with an air motor used for an air tool.

1,6 Disc grinder (Power tool)
DESCRIPTION OF SYMBOLS 2 Tool main-body part 2a Main body case 3 Transmission part 3a Transmission case 4 Gear head part 4a Head case 10 Drive motor 11 Motor spindle 11a, 11b Bearing 12 Fan 20 Transmission control part 21 Transmission motor 22 Drive pulley 23 Actuation shaft 23a Shaft part 24 Driven pulley 25 driving belt 26 operating sleeve 26a hole 27 operating arm 28 operation dial 30 continuously variable transmission mechanism 31 intermediate transmission shaft 31a, 31b bearing 31c stepped portion 31d bearing inner ring 31e sliding clearance 32 sun roller 32a bearing 33 planetary roller 33a support shaft Part 33b Conical surface 34 Thrust roller 34a Boss part 34b Abutting part 35 Pressure regulating spring (pressure regulating thrust means)
36 Transmission ring 37 Holder 37e Support hole 38, 64 Key 40 Reduction unit (output side gear train)
41 Drive side gear 42 Tip clamp 45 Drive side gear 51 Output spindle 51a, 51b Bearing 52 Grinding wheel cover 53 Side grip 60 Pressure regulation cam mechanism (pressure regulation thrust means)
61 Pressing plate 61a Rear surface 61c Insertion hole 61d Cam groove 61d1 Deepest part 61d2 Inclined part 62 Steel ball 63 Thrust needle bearing 67 Pressure regulating spring 69 Conventional cam groove shape B Grinding wheel

Claims (6)

A power tool equipped with a traction drive type continuously variable transmission mechanism,
On the output side of the continuously variable transmission mechanism, an output side gear train that converts rotational drive from the continuously variable transmission mechanism into rotational drive different from the rotational drive is provided,
A power tool characterized in that a mesh drive thrust generated by meshing of drive states of gears constituting the output side gear train is used as a thrust for frictional transmission in the continuously variable transmission mechanism. The power tool according to claim 1,
An intermediate transmission shaft is provided between the continuously variable transmission mechanism and the output side gear train for inputting rotational drive from the continuously variable transmission mechanism side to the gears constituting the output side gear train. ,
The mesh drive thrust is transmitted from the output side gear train to the continuously variable transmission mechanism via the intermediate transmission shaft and used as a thrust for friction transmission in the continuously variable transmission mechanism. Power tool. The power tool according to claim 1 or 2,
Between the continuously variable transmission mechanism and the output side gear train, there is provided a pressure adjusting thrust means for generating a pressure adjusting thrust that is a thrust different from the mesh driving thrust,
A power tool characterized in that the pressure regulation thrust is used as a thrust for frictional transmission in the continuously variable transmission mechanism together with the mesh driving thrust. The power tool according to claim 3,
The pressure regulating thrust means is constituted by a pressure regulating cam mechanism that transmits torque output from the continuously variable transmission mechanism side toward the output side gear train side,
The pressure adjusting cam mechanism has a cam structure that generates the pressure adjusting thrust by a torque received from the continuously variable transmission mechanism side and a load received from the output side gear train side. Power tool to do. In the power tool according to claim 3 or claim 4,
A power tool, wherein a reaction force from the continuously variable transmission mechanism side to the pressure adjusting cam mechanism generated by the pressure adjusting thrust is supported by a housing that rotatably supports the intermediate transmission shaft. The power tool according to any one of claims 1 to 5,
The output-side gear train is configured to include any one of a spiral bevel gear, a straight bevel gear, and a helical gear.

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