JP6988337B2 - Blade and saver saw with it - Google Patents

Description

The present invention relates to a blade that can be attached to a saver saw and a saver saw provided with the blade.

There is a saver saw as a reciprocating type cutting tool driven by an electric motor. As is well known, the saver saw is used for cutting wood, steel, pipes, and other materials to be cut, and is a reciprocating shaft (hereinafter, "plunger") with a saw blade (hereinafter, "blade") attached to the tip. The material to be cut is cut by the blade held by the blade holding means (hereinafter referred to as "blade holder") attached to the reciprocating drive.

FIG. 7 is a side view showing a conventional blade. The blade 135 has a held portion 136 held by the blade holder 23 and a cutting blade portion 1373a, and the upper and lower reference planes are formed in parallel in the held portion 136, and a round hole 1375 is formed between them. It is formed. The lower reference surface and the cutting blade portion 1373a are provided with an angle of, for example, about 5 degrees to 6 degrees in order to improve cutting efficiency. A round hole 1375 is formed in the held portion 136, and this round hole 1375 is used when mounting the round hole 1375 on the blade holder positioning convex portion 233 of the blade holder 23.

The blade holder 23 has a blade holder on the wall 231 and the blade holder lower wall 232 extending in parallel, in a state where the blade holder positioning protrusion 233 is engaged with the round hole 1375, a top wall 231 and bottom wall 232 Are in contact with the upper surface and the lower surface of the held portion 136, respectively, so that the blade 135 is held by the blade holder 23.

Such a blade 135 is described in, for example, Japanese Patent Application Laid-Open No. 2011-131317 (Patent Document 1).

Japanese Unexamined Patent Publication No. 2011-131317

Conventionally, the blade 135 pushed upward by the reaction force of the work material has a gap of, for example, 0.1 mm between the upper surface and the lower surface of the held portion 136 mounted in parallel and the double wall of the blade holder 23. , Attempts to rotate around the round hole 1375. At this time, the upper surface of the held portion 136 collides with the edge portion 231a of the blade holder upper wall 231 and bites into the edge portion 231a of the blade holder upper wall 231 on the upper surface of the held portion 136, causing cracks and the life of the product. The result is a significant loss of.

Further, the blade 135 is pushed downward by the reaction of the upper surface of the non-holding portion 136 colliding with the edge portion 231a, the lower surface of the non-holding portion 136 collides with the edge portion 232a of the blade holder lower wall 232, and the non-holding portion 136 Biting of the edge portion 232a occurs on the lower surface, cracks occur, and the life of the product is significantly shortened.

Therefore, an object of the present invention is to provide a blade having a simple structure, good durability, and a long life.

In order to achieve the above object, the present invention comprises a motor, a motion conversion means for converting the rotational motion of the motor into a reciprocating motion of the plunger, a blade, and a blade holding attached to the tip of the plunger to hold the blade. The blade comprises means, the blade extends in the longitudinal direction and is adjacent to a blade body having a blade at one end in the width direction orthogonal to the central axis and one end in the longitudinal direction of the blade body to the blade holding means. The held portion includes a held portion to be held, and the held portion has a contact portion having a pair of contact surfaces extending in the longitudinal direction at both ends in the width direction and contacting the blade holding means, and the width direction. It has a narrow upper surface located at the other end of the said longitudinally disposed between the abutment portion and the blade body, wherein is less narrow length in the width direction than the contact portion possess the parts, the longitudinal and the through hole penetrating through the held portion in the lateral direction orthogonal to the width direction, wherein the blade holding means includes a protruding portion fitted in the through hole, the longitudinal It has a flat surface having a flat shape extending in the longitudinal direction from a position where the position in the direction overlaps with the contact portion to the blade main body side end portion of the blade holding means, and the flat surface is the flat surface. In a state where the surface abuts on the abutting surface of the abutting portion and the protruding portion fits into the through hole so that the blade holding means holds the blade, the surface of the abutting portion is in contact with the upper surface of the narrow portion. We provide a saver saw that is characterized by not coming into contact with each other.

The blade body has a central portion having a constant length in the width direction and larger than the narrow portion, and one end side in the longitudinal direction adjacent to the central portion and the narrow portion, and has a length in the width direction. It is desirable to have an enlarged portion that gradually expands from the narrow portion side to the central portion side.

It is desirable that the length of the narrow portion in the width direction decreases from the contact portion side to the enlarged portion side at a constant rate.

The pair of contact surfaces are located at one end in the width direction and are located at one end in the width direction and abut on the blade holding means, and are located at the other end in the width direction and extend in parallel with the contact top surface. and a contact with the contact lower surface and said narrow portion upper surface, extending beauty before Symbol enlarged portion side in a direction away from the extension line of the abutment upper surface, the narrow portion, the other end in the width direction The enlarged portion side is located and has a narrow portion lower surface extending in a direction away from the extension line of the contact lower surface, and the narrow portion upper surface and the narrow portion with respect to the vertical line of the contact upper surface and the contact lower surface. It is desirable that the angle formed by the lower surface is larger than 75 degrees and smaller than 87 degrees.

The through holes, the distance between the front Symbol longitudinal direction of the position overlapping at least a portion the narrow portion, the through-hole center and the contact top end portion of the front SL narrow portion upper surface, said narrow portion It is desirable that it is equal to the distance between the end of the lower surface on the lower surface side of the contact and the center of the through hole.

The enlarged portion has an enlarged portion upper surface located at one end in the width direction and an enlarged portion lower surface located at the other end in the width direction, with respect to the contact upper surface and a reference straight line parallel to the contact lower surface. It is desirable that the angle formed by the upper surface of the enlarged portion and the lower surface of the enlarged portion is larger than 50 degrees and smaller than 75 degrees.

It is desirable that the flat surface has an upper wall and a lower wall, and the held portion abuts on the upper wall and the lower wall only by the abutting portion.

Further, the present invention is a blade attached to a saver saw including a motor, a motion conversion means for converting the rotational motion of the motor into a reciprocating motion of the plunger, and a blade holding means attached to the tip of the plunger. A blade body extending in the longitudinal direction and having a blade portion at one end in the width direction orthogonal to the central axis, and a held portion adjacent to one end in the longitudinal direction of the blade body and held by the blade holding means. The held portion is provided with a contact portion having a pair of contact surfaces extending in the longitudinal direction at both ends in the width direction and contacting the blade holding means, and a narrow portion located at the other end in the width direction. A narrow portion having an upper surface, provided between the abutting portion and the blade main body in the longitudinal direction, and having a smaller length in the width direction than the abutting portion, and the longitudinal direction and the width direction. The blade holding means has a through hole that penetrates the held portion in the left-right direction orthogonal to the through hole, and the position of the protruding portion that fits into the through hole and the contact portion in the longitudinal direction overlaps with the contact portion. It has a flat surface having a flat shape extending from a position to the end of the blade holding means on the blade body side and extending in the longitudinal direction, and the upper surface of the narrow portion has the contact surface of the contact portion. It is characterized in that it does not abut on the flat surface in a state where the held portion is held by the blade holding means by abutting on the flat surface and fitting the protruding portion into the through hole. We provide blades .

According to the present invention, it is possible to provide a blade having good durability and long life with a simple configuration.

It is sectional drawing of the saver saw which attached the blade which concerns on embodiment of this invention. It is a side view of the blade which concerns on embodiment of this invention. It is a partially enlarged view of the blade which concerns on embodiment of this invention, and is a perspective view. It is a partially enlarged view of the blade which concerns on embodiment of this invention, and is a side view. It is a partially enlarged view of the blade which concerns on the modification of embodiment of this invention, and is the side view. It is a table which shows the optimum value range of the dimensional relation of the blade which concerns on embodiment of this invention. It is a side view of a conventional blade.

The present invention will be described with reference to FIGS. 1 to 6. In the following figures, parts having the same function are designated by the same reference numerals, and the description of repetition will be omitted. Further, in the present specification, the front-back and up-down directions are described as being the directions shown in FIG.

FIG. 1 is a cross-sectional view showing the entire saver saw which is a power tool according to an embodiment of the present invention. The electric motor 1 is built in a resin motor housing 2, and a handle 3 is connected to the rear of the motor housing 2. An aluminum gear cover 6 for accommodating the power transmission means is provided in front of the motor housing 2. A drive gear 8 is formed at the tip of the motor shaft 7. The rotational motion of the motor shaft 7 is converted into the reciprocating motion of the plunger 20 by the motion conversion means. The motion conversion means includes a spindle 9 provided perpendicular to the motor shaft 7, a driven gear 10 attached to the spindle 9, and a connecting piece 11 attached to the driven gear 10.

The electric motor 1 rotates the connecting piece 11 via the reduction drive gear 8 and the driven gear 10. The connecting piece 11 engages with a recess (not shown) of the plunger 20, and the connecting piece 11 is provided so as to rotate and reciprocate integrally with the plunger 20. With the above configuration, the rotational motion of the deceleration drive gear 8, the driven gear 10, and the connecting piece 11 is converted into the reciprocating motion of the plunger 20.

The blade 35 engages with the blade holder positioning convex portion 233 with the round hole (through hole) 375 of the blade in the blade holder (blade holding means) 23 in front of the plunger 20, and the blade for this positioning It is rotatably about a small angle around the round hole 375 and is fixed by a blade fixing bolt (not shown).

FIG. 2 is an overall side view of the blade 35. The blade 35 has a blade body 37 extending in the longitudinal direction B and a held portion 36 adjacent to one end of the blade body 37 in the longitudinal direction B. The blade main body 37 has a plate shape having two facing surfaces, and has a cutting blade portion (blade portion) 373a at one end in the width direction A in the vertical direction of the facing surfaces. The blade portion 373a is configured by mounting fine diamond abrasive grains, but is not limited to this configuration, and may be a saw blade in which a plurality of sharp protrusions are continuously provided.

FIG. 3 is a perspective view which is a partially enlarged view of the blade 35, and FIG. 4 is a side view which is a partially enlarged view of the blade 35. The held portion 36 has a contact portion 361 having a contact surface that abuts on the blade holder 23. This contact surface is located at the upper end of the contact portion 361 in the width direction A, extends in the longitudinal direction B of the blade main body 37, and has a contact upper surface 361a that abuts on the blade holder upper wall 231 and the width of the contact portion 361. It has a contact lower surface 361b, which is located at the lower end in the direction A, extends in the longitudinal direction B of the blade body 37, and abuts on the blade holder lower wall 232. When the round hole 375 is engaged with the blade holder positioning protrusion 233, the contact upper surface 361a abuts on the blade holder upper wall 231 and the contact lower surface 361b abuts on the blade holder lower wall 232, whereby the blade 35 Is fixed to the blade holder 23 in a state where excessive rattling is suppressed (rotation beyond the minute angle around the above-mentioned round hole 375 is suppressed).

The held portion 36 has a narrow portion that is adjacent to the blade main body 37 side of the contact portion 361 and has a smaller length in the width direction A than the contact portion 361. The narrow portion 362 is located at the upper end in the width direction A, and is located at the lower end in the width direction A and the narrow portion upper surface 362a whose blade body 37 side extends (inclines) in a direction away from the extension line of the contact upper surface 361a. The blade main body 37 side has a narrow portion lower surface 362b extending (inclining) in a direction away from the extension line of the contact lower surface 36ab. That is, the narrow portion 362 is formed so that the length in the width direction A gradually decreases from the contact portion 361 side to the blade main body portion 37 side. Both the narrow portion upper surface 362a and the narrow portion lower surface 362b are formed in a planar shape, and the length of the narrow portion 362 in the width direction A is a constant ratio from the contact portion 361 side to the blade body 37 side. Decreases with. Further, the distance L1 between the contact upper surface 361a side end portion 362c of the narrow portion upper surface 362a and the center (through hole center) 375a of the round hole 375, and the contact lower surface 361b side end portion 362d and the center of the narrow portion lower surface 362b. The distance L2 from 375a is equal to each other.

When the blade 35 is held by the blade holder 23, as described above, the contact upper surface 361a abuts on the blade holder upper wall 231 and the contact lower surface 361b abuts on the blade holder lower wall 232, but the narrow portion upper surface 362a. Does not abut on the upper wall 231 of the blade holder, and the lower surface 362b of the narrow portion does not abut on the lower wall 232 of the blade holder. In other words, since the narrow portion 362 is provided, the held portion 36 abuts on the blade holder 23 only by the contact upper surface 361a and the contact lower surface 361b, and is different from the edge portions 231a and 232a located on the narrow portion 362 side. There is no contact. Therefore, it is possible to prevent the edge portions 231a and 232a from biting into the held portion 36, causing cracks and significantly impairing the life of the product. Further, since it is only necessary to provide the narrow portion 362 on the blade 35, it is possible to suppress the life of the product from being impaired by the inexpensive configuration.

Although it is possible to incline only the narrow portion upper surface 362a to form the narrow portion as in the modified example shown in FIG. 5, the narrow portion upper surface 362a and the narrow portion lower surface 362b are formed as shown in FIGS. 2 to 4. It is advantageous to incline both of them in that the biting by both the edge portions 231a and 232a can be suppressed and stress concentration can be avoided, and that the narrow portion 362 has elasticity to disperse the load.

The blade main body 37 has a central portion 373 whose length in the width direction A is constant and larger than the width of the narrow portion 362, and is adjacent to the central portion 373 on the rear end side in the longitudinal direction B, and has a length in the width direction A. It has an enlarged portion 374 that gradually expands from the narrow portion 362 side to the central portion 373 side. The enlarged portion 374 includes a flat upper surface of the enlarged portion 374a and a lower surface of the enlarged portion 374b. The angle formed by the narrow upper surface 362a and the narrow lower surface 362b with respect to the reference straight line 361c parallel to the contact upper surface 361a and the contact lower surface 361b is such that the enlarged portion upper surface 374a and the enlarged portion lower surface 374b are formed with respect to the reference straight line 361c. It is smaller than the angle it makes. The connection portion between the narrow portion upper surface 362a and the enlarged portion lower surface 374a, and the connection portion between the narrow portion lower surface 362b and the enlarged portion lower surface 374b each have an R shape having a predetermined curvature.

FIG. 6 shows a specific range of optimum values related to dimensions. When the distance between the edge portion 232a of the blade holder lower wall 232 and the end portion 362d of the contact lower surface 361b is h, and the distance between the round hole center 375a and the edge portion 232a of the blade holder lower wall 232 is o, h. It is preferable that the value of is larger than 1/3 times the value of o and smaller than the value of o. The angle i formed by the vertical line of the contact lower surface 361b and the narrow portion lower surface 362b is preferably larger than 75 degrees and smaller than 87 degrees. The distance j between the contact lower surface 361b and the narrow portion lower surface 362b in the width direction A is preferably larger than 0.5 mm and smaller than 1.0 mm. The angle e formed by the lower surface of the enlarged portion 374b and the lower surface of the contact surface 361b is preferably larger than 50 degrees and smaller than 75 degrees. The connection portion between the narrow portion lower surface 362b and the enlarged portion lower surface 374b has an R shape having a curvature Rn, and the contact lower surface is formed from the intersection of the extension line of the narrow portion lower surface 362b and the extension line of the enlarged portion lower surface 374b. When the distance to the end portion 362d of 361b is d, the radius of curvature of Rn should be larger than 1/2 of d and smaller than d. The optimum values for each parameter are 4.7 mm for h, 85 degrees for i, 0.7 mm for j, 60 degrees for e, and 5 mm for Rn when o is 5.5 mm and the width of the blade body is 25 mm. It becomes. It is optimal that the narrow portion upper surface 362a side also has a line-symmetrical shape with the narrow portion lower surface 362b centered on the widthwise central axis of the held portion 36, and the same dimensional relationship is the optimum value range.

As described above, according to the present invention, it is possible to prevent the edge portions 231a and 232a from biting into the held portion 36, causing cracks and significantly impairing the life of the product. Further, since it is only necessary to provide the narrow portion 362 on the blade 35, it is possible to suppress the life of the product from being impaired by the inexpensive configuration. Further, the narrow portion 362 can be made elastic to disperse the load and avoid stress concentration. Specifically, in the configurations shown in FIGS. 1 to 4, it is known by CAE analysis that the maximum stress is reduced by 45%. According to a comparative experiment by the inventor, the product life (crack in the blade) is twice as long as the conventional configuration shown in FIG. 6 and four times as long as the configuration shown in FIGS. 1 to 4. Etc., and the period until it became unusable) could be obtained. In order to quadruple the life of conventional products, methods using production technology such as induction hardening are also being studied. According to this method, it is possible to extend the service life, but the cost increases due to the addition of processing costs. By using this embodiment, it is possible to extend the life regardless of whether or not quenching is performed, and it is possible to provide an inexpensive blade having good durability and long life, and a saver saw having the blade. It will be possible.

The blade according to the present invention and the saver saw provided with the blade are not limited to the above-described embodiments and modifications, and various modifications can be made within the scope of the gist of the invention described in the claims.

1 Electric motor, 2 Motor housing, 3 Handle, 6 Gear cover, 7 Motor shaft, 8 Drive gear, 9 Spindle, 10 Driven gear, 11 Connecting piece, 20 Plunger, 23 Blade holder (blade holding means), 231 Blade holder upper wall , 231a edge part, 232 blade holder lower wall, 232a edge part, 233 positioning protrusion, 135 blade, 136 held part, 1373a cutting blade part, 1375 round hole (through hole), 35 blade, 36 held part, 361 Abutment part, 361a abutment upper surface, 361b abutment lower surface, 361c reference straight line, 362 narrow part, 362a narrow part upper surface, 362b narrow part lower surface, 362c, 362d end part, 37 blade body, 373 center part, 373a Cutting blade part, 374 enlarged part, 374a enlarged part upper surface, 374b enlarged part lower surface, 375 round hole (through hole), 375a round hole center (through hole center), 38 blade tip, A width direction, B longitudinal direction

Claims (8)

With the motor
A motion conversion means for converting the rotational motion of the motor into the reciprocating motion of the plunger,
With the blade,
A blade holding means, which is attached to the tip of the plunger and holds the blade, is provided.
The blade
A blade body that extends in the longitudinal direction and has a blade at one end in the width direction orthogonal to the central axis.
A held portion adjacent to one end of the blade body in the longitudinal direction and held by the blade holding means.
The held portion is
A contact portion having a pair of contact surfaces extending in the longitudinal direction and contacting the blade holding means at both ends in the width direction.
It has an upper surface of a narrow portion located at the other end in the width direction, is provided between the contact portion and the blade main body in the longitudinal direction, and has a smaller length in the width direction than the contact portion. and stomach narrow portion,
Have a, a through hole penetrating the held portion in the lateral direction orthogonal to the longitudinal direction and the width direction,
The blade holding means is
A protrusion that fits into the through hole and
It has a flat surface having a flat shape extending in the longitudinal direction from a position where the position in the longitudinal direction overlaps with the contact portion to the end portion of the blade holding means on the blade body side.
The flat surface is in a state where the blade holding means holds the blade by contacting the flat surface with the contact surface of the contact portion and fitting the protruding portion into the through hole. A saver saw characterized in that it does not abut on the upper surface of the narrow portion. The blade body is
A central portion having a constant length in the width direction and larger than the narrow portion, and a central portion.
Having an enlarged portion which is adjacent to the central portion and the narrow portion on the one end side in the longitudinal direction and whose length in the width direction gradually expands from the narrow portion side to the central portion side. The saver saw according to claim 1. The saver saw according to claim 2, wherein the narrow portion has a length in the width direction that decreases from the contact portion side to the enlarged portion side at a constant rate. The pair of contact surfaces are located at one end in the width direction and are located at one end in the width direction and abut on the blade holding means, and are located at the other end in the width direction and extend in parallel with the contact top surface. Has a contact bottom surface that abuts with
The narrow portion upper surface, extending Beauty before Symbol enlarged portion side in a direction away from the extension line of the abutment upper surface,
The narrow portion has a narrow bottom surface of the enlarged portion located at the other end extending in a direction away from the extension line of the abutment lower surface in the width direction,
2. The saver saw described in. The through hole is positioned in front Symbol longitudinal direction overlaps at least a portion the narrow portion,
The distance between said through-hole center and abutting the upper surface side end portion of the front SL narrow portion upper surface, characterized in that equal to the distance between the through-hole center and the abutment lower surface side end of the narrow lower surface The saver saw according to claim 4. The enlarged portion has an upper surface of the enlarged portion located at one end in the width direction and a lower surface of the enlarged portion located at the other end in the width direction.
4. The saver saw according to 5. The flat surface has an upper wall and a lower wall.
The saver saw according to any one of claims 1 to 6, wherein the held portion abuts on the upper wall and the lower wall only by the contact portion. With the motor
A motion conversion means for converting the rotational motion of the motor into the reciprocating motion of the plunger,
A blade attached to a saver saw provided with a blade holding means attached to the tip of the plunger.
A blade body that extends in the longitudinal direction and has a blade at one end in the width direction orthogonal to the central axis.
A held portion adjacent to one end of the blade body in the longitudinal direction and held by the blade holding means.
The held portion is
A contact portion having a pair of contact surfaces extending in the longitudinal direction and contacting the blade holding means at both ends in the width direction.
It has an upper surface of a narrow portion located at the other end in the width direction, is provided between the contact portion and the blade main body in the longitudinal direction, and has a smaller length in the width direction than the contact portion. Narrow part and
It has a through hole that penetrates the held portion in the left-right direction orthogonal to the longitudinal direction and the width direction.
The blade holding means is
A protrusion that fits into the through hole and
It has a flat surface having a flat shape extending in the longitudinal direction from a position where the position in the longitudinal direction overlaps with the contact portion to the end portion of the blade holding means on the blade body side.
On the upper surface of the narrow portion, the contact surface of the contact portion abuts on the flat surface and the protrusion is fitted into the through hole, so that the held portion is held by the blade holding means. A blade characterized in that it does not abut against the flat surface in the closed state.

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