CN103358211A - Power tool - Google Patents

Abstract

The present invention relates to a power tool. The first groove and protruding joint and the second groove and protruding joint are provided between the fan guide and one end and between the base plate and the other end, respectively, so that the fan guide and the leg One end of one end of the swingable buttress against each other and the other end of the base plate and the leg are swingably close to each other, and the deflection of the leg relative to the fan guide and the base plate in the horizontal direction is limited to allow the leg the rocking of the fan guide and the base. During the orbital movement of the base, the legs can sway with little resistance without involving elastic deformation, and unlike the prior art, the pressure causing the elastic deformation is not applied to the legs.

Description

power tool

Cross References to Related Applications

This application claims priority from Japanese Patent Application No. 2012-074260 filed on Mar. 28, 2012, the contents of which are hereby incorporated by reference into this application.

technical field

The present invention relates to a power tool provided with a main body portion having a drive source, a rotary shaft provided in the drive source, and a base that moves in a horizontal direction relative to the main body portion in an approximately circular motion with rotation of the rotary shaft, and Power tools perform abrasive work using a polishing pad held by a base.

Background technique

Conventionally, a power tool is used to effectively grind and smooth the surface of wood, etc., and the power tool includes a so-called orbital sander provided with a main body portion having a driving source, a rotating shaft provided in the driving source, and a The rotation of the shaft (performing an orbital motion) relative to the base portion of the base makes approximately a circular motion in a horizontal direction. In addition, the base is designed to hold polishing paper (polishing sheet). Therefore, when the user holds the handle of the main body to rotationally drive the drive source and press the polishing paper onto the surface of wood or the like, the base orbits relative to the main body to effectively grind and smooth the surface of wood or the like .

Such an orbital sander (power tool), for example, is known as a power tool described in Laid-Open Japanese Patent Application Publication No. 2008-100302 (Patent Document 1). In the electric tool (power tool) described in Patent Document 1, a motor (drive source) is accommodated in a housing (main body portion), and a ball bearing is provided at a distal end portion of a motor shaft (rotation shaft) of the motor so that Offset from the axial center of the motor shaft. In addition, a base provided with a pad holding the polishing paper is fixed to the bearing, and a plurality of flexible legs (pillars) are provided between the housing and the base and surround the ball bearing. These legs limit the relative rotation of the base relative to the housing and allow rocking motion of the base relative to the housing centered around ball bearings so that the base (polishing paper) orbits as the motor shaft rotates.

However, according to the power tool described in the above Patent Document 1, since one end of each post is fixed to the main body portion and the other end is fixed to the base, each time the base orbits relative to the main body, that is, every time When powered tools are used, the individual posts are repeatedly elastically deformed, such as extending and contracting. Therefore, when each post deteriorates due to long-term use of the power tool, in some cases, breakage occurs on each post, which necessitates maintenance such as replacement. Especially, in the case where the power tool is frequently used in a place where the ambient temperature is low, not only the damage of each post is quickened to shorten the maintenance period, but also each post becomes hard and difficult to be elastically deformed. As a result, the operating resistance of the base increases, which may cause a problem of reduced grinding performance.

Contents of the invention

An object of the present invention is to provide a power tool capable of preventing an increase in operational resistance of a base and prolonging a maintenance cycle of a column.

According to one embodiment, a power tool includes: a main body portion having a driving source; a rotating shaft provided in the driving source; and a base that moves in an approximately circular motion in a horizontal direction relative to the main body portion as the rotating shaft rotates, the power tool Abrasive work is performed with a polishing pad held by a base. The power tool is characterized in that the post is provided between the main body portion and the base; and the groove and the protruding joint are respectively provided between the main body portion and one end of the post and between the base and the other end of the post, respectively having the main body portion and one end portion swingably abutted against each other and the base portion and the other end portion being rockably abutted against each other, and restricting horizontal deflection of the post relative to the main portion and base portion while allowing the post relative to the main portion and the rocking of the base.

According to the invention, during the orbital movement of the base, the column oscillates with little resistance and does not involve any elastic deformation. Therefore, the pressure (load) that elastically deforms the column in the related art is not applied to the column, and an increase in the operation resistance of the base can be prevented and the life of the column can be extended to prolong the maintenance cycle.

Description of drawings

1 is a perspective view showing an orbital sander according to a first embodiment of the present invention;

Fig. 2 is a partial sectional view of the orbital sander taken along the longitudinal direction of the orbital sander viewed from the side of arrow A in Fig. 1;

Fig. 3 is a partial cross-sectional view of a portion B surrounded by a dotted line in Fig. 2 shown in an enlarged manner;

FIG. 4A is an operation explanatory diagram for explaining an operation state of a leg;

FIG. 4B is an operation explanatory diagram for explaining an operation state of a leg;

5 is a partial cross-sectional view showing a leg portion and its surrounding structure according to a second embodiment and corresponding to FIG. 3;

FIG. 6 is a partial sectional view showing a leg portion and its surrounding structure according to a third embodiment and corresponding to FIG. 3; and

Fig. 7 is a partial sectional view showing a leg portion and its surrounding structure according to a fourth embodiment and corresponding to Fig. 3 .

Detailed ways

Hereinafter, a first embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a perspective view showing an orbital sander according to a first embodiment of the present invention, and Fig. 2 is a perspective view of the orbital sander taken along the longitudinal direction of the orbital sander viewed from the side of arrow A in Fig. 1 Partial sectional views, FIG. 3 is a partial sectional view of a portion B surrounded by a dotted line in FIG. 2 shown in an enlarged manner, and FIGS. 4A and 4B are operation explanatory views for explaining an operating state of the legs.

As shown in FIGS. 1 and 2 , an orbital sander 10 as a power tool is provided with a sander main body 20 and a base 30 . The sander main body 20 is provided with a housing 21 that can be divided into left and right sides (distal and proximal in FIG. 1 ) along the longitudinal direction of the orbital sander 10, and the housing 21 is made of a resin material such plastic) formed to have a hollow shape.

The housing 21 is provided with a motor housing portion 21a and a grip portion 21b. A motor 22 serving as a drive source in an upright position is accommodated inside the motor housing portion 21a, and an operation switch 11 for turning the orbital sander 10 off and on is provided on the grip portion 21b. A brake button 12 (see FIG. 1 ) is provided in the vicinity of the operation switch 11 on the grip portion 21b. Then, by pressing the stop button 12 in a state where the operation switch 11 has been operated to be on, a continuous operation state in which the operation switch 11 is not operated to be off is realized.

Here, in order to easily understand the internal structure of the housing 21, the electric wires for electrically connecting the operation switch 11 and the motor 22, the power cord 13, the polishing paper 14 and the clip 15 (see FIG. 1 ), etc. are omitted in FIG. 2 . Show.

A fan guide 23 having a predetermined shape formed of a resin material such as plastic is provided inside the housing 21 near the base 30 . A fan guide 23 is fixed inside the housing 21 , and a rotation shaft 22 a extending in a downward direction below the motor 22 passes through an approximately center portion of the fan guide 23 . The rotary shaft 22a of the motor 22 is rotatably supported by the first radial bearing B1 attached to the fan guide 23, and the cooling fan 24 is fixed to the distal end of the rotary shaft 22a axially below the first radial bearing B1. side, thereby rotating integrally with the rotating shaft 22a. Here, the grinder main body 20 is composed of a housing 21 and a fan guide 23, and the housing 21 and the fan guide 23 constitute the main body of the present invention.

The cooling fan 24 is rotatably accommodated in the inside of the fan guide part 23 by the powder guide part 25. In addition to the cooling function of the cooling motor 22, the cooling fan 24 is also provided with a powder collection function to collect the grinding powder ( not shown). A plurality of cooling fins 24 a are provided on the motor 22 side of the cooling fan 24 , and a plurality of powder collecting fins 24 b are provided on the base 30 side of the cooling fan 24 so as to face the exhaust port 25 a of the powder guide 25 . Therefore, external air can be supplied into the motor 22 with the rotation of the cooling fan 24, and ground powder can be supplied into the inside of the powder collection bag 26 (see FIG. 1) through the exhaust port 25a. Here, the powder collecting bag 26 is formed, for example, from a cloth having a mesh size that allows air to pass through but not powder to pass through.

The eccentric member 27 is fixed by a fastening screw S to the distal end side of the rotary shaft 22a located below the cooling fan 24 in the axial direction of the rotary shaft 22a. The eccentric member 27 is designed to perform orbital motion (eccentric circular motion) around the axial center C2 at a position eccentric (deviated) by about 1.0 mm from the axial center C1 of the rotary shaft 22a, and the inner side of the second radial bearing B2 is attached to A member main body 27a of the eccentric member 27 is formed. In addition, the cylindrical portion 31d integrally provided on the base plate 31 forming the base 30 is fixed to the outside of the second radial bearing B2 so that the base 30 is also orbitally moved by the eccentric member 27 following the rotation of the rotation shaft 22a. The orbital movement is performed by the second radial bearing B2. More specifically, the base 30 is designed to move approximately in a circular motion in the horizontal direction relative to the housing 21 and the fan guide 23 with the movement of the eccentric member 27 .

The weight 27b is partially provided around the member main body 27a so as to eliminate (negate) the vibration in the horizontal direction caused by the orbital motion of the base 30 . Specifically, as shown in FIG. 2, when the base 30 moves to the right in FIG. 2, the weight 27b moves to the left in FIG. Therefore, by eliminating vibration in the horizontal direction during operation of the orbital sander 10 in this manner, it is possible to prevent the movement of the grip portion 21b held by the worker in the horizontal direction.

The base 30 is composed of a base plate 31 made of an aluminum material and a sponge-like pad 32 made of a rubber material to which a polishing paper 14 (see FIG. 1 ) serving as a polishing sheet is attached. When the polishing paper 14 is attached to the pad 32, both ends of the polishing paper 14 in the longitudinal direction of the orbital sander 10 are folded back to the sides of the base plate 31 and they are secured by the clips 15 attached to the base plate 31. fixed. Here, holes are also formed in the polishing paper 14 to coincide with powder collecting holes (not shown) formed in the base plate 31 and the pad 32 . Therefore, grinding powder generated during the grinding work is collected in the powder collecting bag 26 through the holes formed in the polishing paper 14, the powder collecting holes, and the powder guide 25 (exhaust port 25a).

A total of four leg portions (pillars) 40 are provided between the fan guide portion 23 forming the sander main body 20 and the base plate 31 forming the base 30 . Although only two legs are shown in FIG. 2 , each leg 40 is formed in an approximately columnar shape from an elastic material such as rubber, and they are spaced at predetermined intervals along the horizontal direction of the fan guide 23 and the base plate 31. It is provided at front, rear, left and right positions so that the rotation shaft 22a of the motor 22 intervenes. Here, since the respective leg portions 40 and their surrounding structures are completely identical to each other, one leg portion 40 and its surrounding structures will be specifically described with reference to FIG. 3 .

As shown in FIG. 3 , a first groove and protrusion engaging portion (groove and protrusion engaging portion) 50 is provided on the bottom side surface 23a of the fan guide portion 23 and one end portion 40a of the leg portion 40 (in FIG. 3 . upper side). The first groove and protrusion engaging portion 50 is composed of a columnar member 51 integrally formed so as to extend in the axial direction of the rotation shaft 22a from the bottom side surface 23a toward the base plate 31, and a spherical groove portion 52. The portion 52 is formed to be recessed from one end portion 40a of the leg portion 40 toward the other end portion 40b thereof. A spherical protrusion 51 a is integrally provided at the distal end of the cylindrical member 51 , and the spherical protrusion 51 a abuts against the spherical groove portion 52 . Therefore, the swing of the leg 40 relative to the fan guide 23 is allowed, and the axial offset of the leg 40 relative to the fan guide 23 , that is, the relative movement of the leg 40 in the horizontal direction relative to the fan guide 23 (Offset) is restricted.

The radius R1 of the spherical convex portion 51a is set to be slightly smaller than the radius R2 of the spherical concave portion 52a (R1<R2). Therefore, the distal end of the spherical protrusion 51 a is in point contact with the bottom of the spherical groove portion 52 . In this way, the spherical convex portion 51a and the spherical groove portion 52 are in point contact with each other, during the orbital movement of the base 30, the leg portion 40 can be smoothly swung with little resistance. Here, the height of the columnar member 51 including the spherical protrusion 51 a is set to be greater than the depth of the spherical groove portion 52 . In this way, in the rocking action of the leg 40 relative to the fan guide 23 , contact between the one end 40 a of the leg 40 and the bottom side surface 23 a is prevented, so that the base 30 can orbit smoothly.

The annular first surrounding wall 23 b is integrally provided around the columnar member 51 of the fan guide 23 so as to surround the columnar member 51 . One end portion 40a of the leg portion 40 in its longitudinal direction is accommodated in the first surrounding wall 23b in a non-contact state, and the height of the first surrounding wall 23b from the bottom side surface 23a is set to h1. By setting the height of the first surrounding wall 23a to h1 in this way, about 1/3 of the leg portion 40 in its longitudinal direction is covered by the first surrounding wall 23b. As a result, even if the leg 40 is largely elastically deformed for any reason, the leg 40 is prevented from rushing out of the first surrounding wall 23b.

A tapered surface 23c tapered toward the distal end (lower side in FIG. 3) of the first surrounding wall 23b is formed on the radially inner side of the first surrounding wall 23b. The inclination angle of the tapered surface 23 c is set to α°, and the inclination angle α° is set to be equal to the maximum inclination angle of the leg 40 when the leg 40 swings. In this way, when the orbital sander 10 is assembled, the one end 40a of the leg 40 is easily accommodated in the first surrounding wall 23b. In addition, contact between the leg 40 and the first surrounding wall 23b can be prevented during the rocking motion of the leg 40, so that the base 30 can orbit smoothly (see FIG. 4).

The second groove and protrusion joint (groove and protrusion joint) 60 is provided between the fan guide side surface 31 a of the base plate 31 and the other end 40 b (the lower side in FIG. 3 ) of the leg 40 . The second groove and protrusion engaging portion 60 is composed of a cylindrical member 61 integrally provided so as to extend from the fan guide side surface 31a toward the fan guide portion 23 in the axial direction of the rotation shaft 22a, and a spherical groove portion 62, The spherical groove portion 62 is formed to be recessed from the other end portion 40b of the leg portion 40 toward the one end portion 40a thereof. The spherical protrusion 61 a is integrally provided at the distal end of the columnar member 61 , and the spherical protrusion 61 a abuts against the spherical groove portion 62 . Therefore, the swing of the leg 40 with respect to the base plate 31 is allowed, and the axial offset of the leg 40 with respect to the base plate 31, that is, the relative movement (the offset) of the leg 40 in the horizontal direction with respect to the base plate 31 ) is restricted.

The radius R1 of the spherical convex portion 61 a is set to be slightly smaller than the radius R2 of the spherical concave portion 62 ( R1 < R2 ). Therefore, the distal ends of the spherical protrusions 61 a and the bottoms of the spherical grooves 62 are in point contact with each other. By making the spherical protrusion 61 a and the spherical groove 62 point-contact each other in this way, the leg 40 can smoothly swing with little resistance during the orbital movement of the base 30 . Here, the height of the columnar member 61 including the spherical protrusion 61 a is set larger than the depth of the spherical groove portion 62 . In this way, in the rocking motion of the leg 40 relative to the base plate 31, contact between the other end 40b of the leg 40 and the fan guide side surface 31a is prevented, so that the base 30 can orbit smoothly. .

The annular second surrounding wall 31 b is integrally provided around the columnar member 61 of the base plate 31 so as to surround the columnar member 61 . The other end portion 40b of the leg portion 40 in its longitudinal direction is accommodated in the second surrounding wall 31b in a non-contact state, and the height of the second surrounding wall 31b from the fan guide side surface 31a is set to h2 (h2<h1). By setting the height of the second surrounding wall 31b to h2 in this way, about 1/4 of the leg portion 40 in its longitudinal direction is covered by the second surrounding wall 31b. As a result, even if the leg portion 40 is largely elastically deformed for any reason, the leg portion 40 is prevented from rushing out from the second surrounding wall 31b.

Here, the height h1 of the first surrounding wall 23b and the height h2 of the second surrounding wall 31b may be set arbitrarily, respectively. For example, they may be set to have a size relationship opposite to that described above. However, in setting the heights h1 and h2, it is desirable to form a predetermined gap (about 1/4 the size of the leg portion 40 in the longitudinal direction) between the first surrounding wall 23b and the second surrounding wall 31b so as to absorb Slight displacement of base 30 relative to fan guide 23 during operation of orbital sander 10 .

A tapered surface 31c tapered toward the distal end (upper side in FIG. 3 ) of the second surrounding wall 31b is formed on the radially inner side of the second surrounding wall 31b. The inclination angle of the tapered surface 31c is set to α°, and the inclination angle α° is set to be equal to the maximum inclination angle of the leg 40 when the leg 40 swings. In this way, the other end portion 40b of the leg portion 40 is easily accommodated in the second surrounding wall 31b when the orbital sander 10 is assembled. In addition, contact between the leg 40 and the second surrounding wall 31b can be prevented during the rocking action of the leg 40, so that the base 30 can orbit smoothly (see FIG. 4).

Next, the action of the orbital sander 10 formed in the above manner, especially the swing action of the leg 40 during the orbital movement of the base 30 will be described in detail with reference to the accompanying drawings.

As shown in FIG. 2 , first, when a worker holds the grip portion 21 b of the orbital sander 10 and turns on the operation switch 11 in this state, a drive current is supplied to the motor 22 . Then, the rotary shaft 22a rotates about the axial center C1, and the eccentric member 27 orbits about the axial center C2 along with the rotation. As a result, the base 30 (base plate 31 ) also orbits through the second radial bearing B2, so that the polishing paper 14 (see FIG. 1 ) attached to the pad 32 also orbits. Thereafter, by pressing the polishing paper 14 onto the surface of wood or the like, the pressed portion of the surface can be effectively smoothed.

At this time, as shown by arrows SW1 and SW2 in FIG. 4A and FIG. 4B , the base 30 orbits relative to the fan guide 23, and the legs 40 perform a rocking motion, thereby tilting at the maximum along with the orbital movement of the base 30. Pivoting is performed on the columnar members 51 and 61 within the range of an angle α° (see FIG. 3 ). Here, since FIG. 4A and FIG. 4B are plan views, they only represent the swinging action along the left and right directions (arrows SW1 and SW2) of the leg 40, but the leg 40 actually also moves along the left and right directions in FIG. 4A and FIG. 4B. Depth swings.

In the rocking action of the leg 40, since the leg 40 is made of rubber, it is in point contact with the columnar member 51 made of plastic and the columnar member 61 made of aluminum, and is not elastically deformed, and it is seldom possible for the leg 40 to Premature wear or deterioration occurs without an increase in the operational resistance of the orbital sander 10 . Thus, the life of the legs 40 is extended as compared to the prior art, and only the first groove and male interface 50 and the second groove and male interface 50 are required for maintenance of the orbital sander 10. 60 for regular lubricating oil (lubrication). Furthermore, since the legs 40 are made of rubber, the running noise of the orbital sander 10 can be reduced while absorbing dimensional errors of the parts forming the orbital sander 10 . However, when it is possible to form a portion precisely with little dimensional error, for example, the leg portion 40 may be made of hard plastic or aluminum (a high-hardness member) instead of rubber.

As described above in detail, according to the orbital sander 10 of the first embodiment, the first groove and protrusion engaging portion 50 and the second groove and protrusion engaging portion 60 are provided on the fan guide portion 23 and the one end portion 40a, respectively. Between the base plate 31 and the other end 40b, the first groove and protrusion joint 50 and the second groove and protrusion joint 60 make the fan guide 23 and the one end 40a of the leg 40 The base plate 31 and the other end portion 40b of the leg portion 40 are swingably abutted against each other and the other end portion 40b of the leg portion 40 is swingably abutted against each other, and the deviation of the leg portion 40 relative to the fan guide portion 23 and the base plate 31 in the horizontal direction is restricted. Rocking of the leg portion 40 relative to the fan guide portion 23 and the base plate 31 is allowed. As a result, during the orbital movement of the base 30, the legs 40 can sway with little resistance without involving any elastic deformation. Therefore, since pressure (load) causing elastic deformation is not applied to the legs 40 unlike the related art, an increase in operation resistance of the base 30 can be prevented, and the life of the legs 40 can be extended to prolong the maintenance cycle.

In addition, according to the orbital sander 10 of the first embodiment, the first groove and protrusion engaging portion 50 and the second groove and protrusion engaging portion 60 are composed of spherical balls provided on the fan guide 23 and the base plate 31 , respectively. The protruding portions 51a and 61a are composed of spherical groove portions 52 and 62 provided at one end portion 40a and the other end portion 40b, respectively. In addition, the radius R1 of the spherical protrusions 51 a and 61 a is set smaller than the radius R2 of the spherical grooves 52 and 62 ( R1 < R2 ). Therefore, the fan guide 23 and the leg 40 can point-contact each other, and the base plate 31 and the leg 40 can point-contact each other, so that the legs can swing smoothly.

Next, a second embodiment of the present invention will be specifically described with reference to the drawings. Incidentally, portions having the same functions as those of the above-described first embodiment are denoted by the same reference numerals and detailed descriptions thereof are omitted. Fig. 5 is a partial sectional view showing a leg portion and its surrounding structure according to a second embodiment and corresponding to Fig. 3 .

As shown in FIG. 5, an orbital sander (power tool) 70 according to the second embodiment differs from the orbital sander 10 according to the first embodiment in the structure of the legs and their surroundings. Specifically, the first groove and protrusion joint (groove and protrusion joint) 80 of the orbital sander 70 is composed of a steel ball 81 having a radius R3 and a steel ball having a radius R3 and disposed on a leg (post) 100. One end portion 100a is composed of a spherical groove portion 82. In addition, the second groove and protrusion joint (groove and protrusion joint) 90 of the orbital sander 70 is formed of a steel ball 91 having a radius R3 and having a radius R3 and provided at the other end of the leg 100. The spherical groove portion 92 of 100b is composed.

Here, the respective steel balls 81 and 91 constitute spherical protrusions in the present invention, and the respective steel balls 81 and 91 respectively engage with engaging groove portions formed in the bottom side surface 71a of the fan guide portion (main body portion) 71 71b and the engagement groove portion 72b formed in the fan guide side surface 72a of the base plate 72 are attached.

About half of the respective steel balls 81 and 91 protrude toward the leg 100 , respectively, and they enter the respective spherical groove portions 82 and 92 of the leg 100 to be in sliding contact therewith. Incidentally, the depth of each spherical groove portion 82 and 92 is set to be smaller than the radius R3 of each steel ball 81 and 91 . In this way, in the rocking action of the leg portion 100 , contact between one end portion 100 a and the bottom side surface 71 a and contact between the other end portion 100 b and the fan guide side surface 72 a are prevented.

In the first groove and protrusion joint 80 and the second groove and protrusion joint 90, unlike the first embodiment, the legs 100 and the respective steel balls 81 and 91 are formed by spherical surfaces having the same radius R3. are arranged to abut against each other (sliding contact) in a swingable manner. Therefore, the rattling of the legs 100 can be further suppressed compared to the first embodiment. However, it is desirable that sufficient lubricating oil is applied to the sliding contact portion in order to prevent wear of the leg 100 and to achieve smooth orbital movement of the base 30 .

The orbital sander 70 according to the second embodiment is provided with an annular first surrounding wall 71c having a height h3 projected from the bottom side surface 71a of the fan guide 71; and is also provided with an annular second surrounding wall 72c which There is a height h4 projected from the fan guide side surface 72 a of the base plate 72 ( h4 < h3 ). However, the heights h3 and h4 of the first surrounding wall 71c and the second surrounding wall 72c can be arbitrarily set like the first embodiment (see FIG. 3 ).

An annular gap G1 larger than that in the first embodiment is formed between the first and second surrounding walls 71c and 72c and the leg portion 100 . As a result, in the rocking action of the leg 100, even if the inclination angle of the leg 100 reaches the maximum inclination angle α°, contact between the first and second surrounding walls 71c and 72c and the leg 100 is prevented. Therefore, the tapered surfaces on the radially inner sides of the first and second surrounding walls provided in the first embodiment are not provided.

As specifically explained above, in addition to the functional effect obtained by the "point contact" in the first embodiment described above, in the orbital sander 70 according to the second embodiment, the same functional effect as in the first embodiment can be obtained. Similar functional effects. In addition, since the respective steel balls 81 and 91 are used in the first groove and protrusion joint 80 and the second groove and protrusion joint 90 in the second embodiment, by adopting JIS (Japanese Industrial Standards) or the like, the Multi-purpose steel balls are used as the respective steel balls 81 and 91, so that the cost of the orbital sander 70 can be reduced.

Next, a third embodiment of the present invention will be described in detail with reference to the drawings. Incidentally, portions having the same functions as those of the above-described first embodiment are denoted by the same reference numerals and detailed descriptions thereof are omitted. Fig. 6 is a partial sectional view showing a leg portion and its surrounding structure according to a third embodiment and corresponding to Fig. 3 .

As shown in FIG. 6, an orbital sander (power tool) 110 according to the third embodiment differs from the orbital sander according to the first embodiment in the structure of the legs and their surroundings. Specifically, the grooves and protrusions in the first groove and protrusion joint (groove and protrusion joint) 120 and the second groove and protrusion joint (groove and protrusion joint) 130 The relationship of is inverted from that of the grooves and protrusions in the first embodiment. In other words, the spherical protrusions 121 and 131 having a radius R4 are integrally provided to one end 140a and the other end 140b of the leg (pillar) 140 so as to face the fan guide (main body) 111 and the base The plate 112 protrudes. Here, in the third embodiment, the leg portion 140 is made of aluminum.

A spherical groove portion 122 having a radius R4 into which the spherical protrusion 121 enters and slidably contacts is provided on the bottom side surface 111 a of the fan guide portion 111 . Here, the spherical protrusion portion 121 and the spherical groove portion 122 form the first groove and protrusion engaging portion 120 . On the other hand, a flexible rubber seat 113 is located on the fan guide side surface 112a of the base plate 112, and a spherical groove portion 132 having a radius R4 into which the spherical protrusion 131 enters and slides is provided on the fan guide side of the rubber seat 113. Surface 113a. Here, the spherical protrusion portion 131 and the spherical groove portion 132 form the second groove and protrusion engaging portion 130 . By the way, when the part that can be formed is accurate and almost no dimensional error occurs, a structure may be employed in which the rubber seat 113 is eliminated and a spherical recessed portion is formed in the base plate 112 so that the spherical protrusion 131 enters the spherical recessed portion for sliding contact.

Here, in the rocking action of the leg 140, the contact between the one end 140a of the leg 140 and the bottom side surface 111a and the other end 140b of the leg 140 and the fan guide side surface of the rubber mount 113 are prevented. Contact between 113a. In the first groove and protrusion joint portion 120 and the second groove and protrusion joint portion 130, the leg portion 140 and the spherical groove portions 122 and 132 are provided to be rockable due to passing through spherical surfaces having the same radius R4 The rattling of the legs 140 can be further suppressed as in the second embodiment. However, it is desirable that sufficient lubricating oil is applied to the sliding contact portion in order to prevent wear of the rubber seat 113 and the fan guide 111 and to achieve smooth orbital movement of the base 30 .

The orbital sander 110 according to the third embodiment is provided with an annular first surrounding wall 111 b having a height h5 protruding from the bottom side surface 111 a of the fan guide 111 . In addition, an annular second surrounding wall 112b having a height h6 is provided on the base plate 112 of the orbital sander 110 so as to protrude from the fan guide side surface 113a of the rubber mount 113 (h6<h5). However, the heights h5 and h6 of the first surrounding wall 111b and the second surrounding wall 112b can be arbitrarily set like the first embodiment (see FIG. 3 ).

Like the second embodiment, an annular gap G2 larger than that in the first embodiment is formed between the first and second surrounding walls 111b and 112b and the leg portion 140 . Accordingly, contact between the first and second surrounding walls 111b and 112b and the leg 140 can be prevented even if the inclination angle of the leg 140 reaches the maximum inclination angle α° following the rocking action of the leg 140 . Therefore, in the third embodiment, like the second embodiment, the tapered surfaces on the radially inner sides of the first surrounding wall and the second surrounding wall are not provided.

As specifically described above, in the orbital sander 110 according to the third embodiment, except for the functional effect obtained by the "point contact" in the above-mentioned first embodiment, similar functions to those in the first embodiment can be obtained Effect.

Next, a fourth embodiment of the present invention will be specifically described with reference to the drawings. Incidentally, portions having the same functions as those of the above-described first embodiment are denoted by the same reference numerals and detailed descriptions thereof are omitted. Fig. 7 is a partial sectional view showing a leg portion and its surrounding structure according to a fourth embodiment and corresponding to Fig. 3 .

As shown in FIG. 7, an orbital sander (power tool) 150 according to the fourth embodiment differs from the orbital sander according to the first embodiment in the structure of the legs and their surroundings. Specifically, the first groove and protrusion joint (groove and protrusion joint) 160 of the orbital sander 150 is formed by a conical protrusion provided on the fan guide (main body portion) 151 with an angle β°. 161 and a conical groove portion 162 provided at one end portion 170a of the leg portion (pillar) 170 with an angle γ° (γ°>β°). In addition, the second groove and protrusion joint (groove and protrusion joint) 180 of the orbital sander 150 is composed of a conical protrusion 181 provided on the base plate 152 having an angle β° and a conical protrusion 181 having an angle γ°. And the conical groove part 182 provided on the other end part 170b of the leg part 170 is formed.

The height of the conical protrusion portion 161 from the bottom side surface 151 a of the fan guide portion 151 is set larger than the depth of the conical recess portion 162 from one end portion 170 a of the leg portion 170 . In addition, the height of the conical protrusion portion 181 from the fan guide side surface 152 a of the base plate 152 is set larger than the depth of the conical recess portion 182 from the other end portion 170 b of the leg portion 170 . In this way, in the rocking action of the leg portion 170 , contact between the one end portion 170 a and the bottom side surface 151 a and contact between the other end portion 170 b and the fan guide side surface 152 a are prevented.

However, the leg portion 170 is not limited to being made of rubber, and it may be made of hard plastic or aluminum whose hardness is higher than that of rubber. In this case, in order to reduce the running noise due to the rocking action of the legs 170, rubber mounts may be provided on the base plate 152 like the orbital sander 110 of the third embodiment (see FIG. 6). In this case, the conical protrusion may be integrally provided on the rubber seat or the conical protrusion made of aluminum may be placed on the rubber seat.

As specifically described above, in the orbital sander 150 according to the fourth embodiment, since the distal end portions of the conical protrusions 161 and 181 are almost in point contact with the bottom portions of the conical recesses 162 and 182, the above-mentioned Similar functional effects to the first embodiment.

It is a matter of course that the present invention is not limited to the respective embodiments described above, and various modifications and changes can be made within the gist of the present invention. In the above embodiments, it has been shown that the first surrounding walls 23b, 71c and 111b are provided on the fan guides 23, 71, 111 and 151 and the second surrounding walls 31b, 72c and 112b are provided on the base plates 31, 72, 112 and 152, but the present invention is not limited thereto. For example, if the stiffness of the legs can be increased, the legs will not be elastically deformed and not punched out from the respective walls, and the respective walls can be eliminated. In this case, the structures of the fan guide and the base plate can be simplified, and the manufacturing cost of the orbital sander can be reduced.

Claims (3)

1. A power tool comprising: a main body portion having a driving source; a rotating shaft provided in the driving source; and a base that moves relative to the main body portion in an approximately circular motion in a horizontal direction as the rotating shaft rotates, the The power tool does the grinding work with a polishing disc held by the base, characterized in that the post is disposed between the body portion and the base; and Grooves and protruding joints are respectively provided between the main body portion and one end of the post and between the base and the other end of the post, respectively making the main body portion and the one end swingably abut each other and the base and the post. The other end portions are swingably abutting against each other and limit horizontal deflection of the column relative to the body portion and base while allowing rocking of the column relative to the body portion and base. 2. A power tool according to claim 1, It is characterized in that the groove and the convex joint are composed of spherical protrusions or spherical grooves respectively provided on the body part and the base and spherical grooves or spherical grooves respectively provided on one end and the other end. Composition of protrusions. 3. A power tool according to claim 2, It is characterized in that the radius of the spherical protrusion is set smaller than the radius of the spherical groove.

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