JP2010155292A - Hammer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve assembly efficiency by simplifying a structure concerning the attachment of a crankshaft. <P>SOLUTION: In an electric hammer 1 in which the crankshaft 6 is journaled by a ball bearing 14 positioned inside a fitting recessed part 13 of a crank housing 5, and a gear 11 is provided on the upper part from the ball bearing 14 in the crankshaft 6, the positioning of the ball bearing 14 in the crank housing 5 is performed by a plate-like bearing retainer 12 disposed between the ball bearing 14 and the gear 11, and fixed to the crank housing 5. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an impact tool such as an electric hammer or a hammer drill.

  A hitting tool such as an electric hammer is provided with a hitting mechanism that hits a bit attached to the tip of the housing. In this striking mechanism, an eccentric pin is provided at the upper part of the crankshaft that is rotationally transmitted from the output shaft of the motor, and the eccentric pin is connected to a piston in the cylinder via a connecting rod so that the rotation of the crankshaft is reciprocated by the piston. It is converted into motion, and the striking element is reciprocated in conjunction with the reciprocating movement of the piston, so that the bit is struck directly or indirectly via the intermediate element.

  As shown in Patent Documents 1 and 2, such a crankshaft has a structure in which a gear that meshes with the output shaft of the motor is provided at the lower portion and is supported in the vertical direction with the gear interposed therebetween. For this reason, the housing that supports the crank mechanism is divided into a lower gear housing that supports the lower end of the crankshaft and a crank housing that holds a bearing that supports the crankshaft. However, in consideration of assembly work and the reduction in the number of parts, a structure is also adopted in which a gear is provided on the upper part of the crankshaft and a bearing provided below (an intermediate part of the crankshaft) is supported on the crank housing. Yes. According to this structure, the crank housing and the gear housing can be formed integrally.

JP 2000-84715 A JP-A-11-104974

  However, when the structure is adopted, it is necessary to assemble the crankshaft from the inside of the crank housing once. Specifically, the bearing retainer is assembled first between the crankshaft and the gear, and the crankshaft is assembled to the crank housing and then the bearing retainer is screwed to the crank housing. The property (assembleability) will deteriorate.

  Therefore, the present invention provides a structure in which a gear is provided on an upper portion of a crankshaft so that the crank housing and the gear housing are integrated, and the structure relating to the assembly of the crankshaft can be simplified to improve the assemblability. The purpose is to provide a tool.

In order to achieve the above object, according to the first aspect of the present invention, the positioning of the bearing in the crank housing is performed by a plate-like bearing retainer disposed between the bearing and the gear and fixed to the crank housing. It is a feature.
According to a second aspect of the present invention, in the configuration of the first aspect, the bearing retainer is screwed to the crank housing at a position where it does not overlap with the gear and the bearing in a plan view in order to easily assemble the bearing retainer. It is characterized by this.
According to a third aspect of the present invention, in the configuration of the first aspect, in order to obtain a better assemblability, the front end of the crank housing is connected to a cylindrical barrel that accommodates the striking mechanism, and expands toward the front. While forming the opening with the taper part to open, the front end of the bearing retainer is connected to the taper part of the opening, and the rising part for positioning the front end of the bearing retainer is connected. .
According to a fourth aspect of the present invention, in the structure according to any one of the first to third aspects, in order to easily obtain a bearing retainer that can position the bearing reliably, the bearing retainer passes through the upper surface of the bearing across the crankshaft. It is characterized by having a U-shape in a plan view provided with a pair of left and right pressing portions.
According to a fifth aspect of the present invention, in the configuration of the fourth aspect, in order to easily fix the pressing portion and further improve the assemblability, the locking of the tip of the pressing portion is locked in the crank housing. A groove is formed.

According to the first aspect of the present invention, it is a procedure for assembling the bearing retainer after assembling the crankshaft and the bearing to the crank housing, and the structure relating to the assembling of the crankshaft can be simplified to improve the assemblability. it can. In addition, the bearing retainer has a simple plate shape, which leads to space saving and cost reduction.
According to the second aspect of the present invention, in addition to the effect of the first aspect, the assembly of the bearing retainer in the crank housing can be performed more easily.
According to the third aspect of the present invention, in addition to the effect of the first aspect, the use of the rising portion enables the bearing retainer to be fixed only by the crank housing, so that the screwing with a bolt or the like can be omitted. The number of points decreases, and the assemblability becomes better.
According to the fourth aspect of the invention, in addition to the effect of any one of the first to third aspects, a bearing retainer that can position the bearing reliably can be easily obtained.
According to the fifth aspect of the present invention, in addition to the effect of the fourth aspect, the pressing portion can be easily fixed using the crank housing, which leads to further improvement in assemblability.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view of an electric hammer which is an example of an impact tool. The electric hammer 1 includes a crankshaft 6 provided above a motor housing 2 that houses a motor 3 with an output shaft 4 facing upward. A crank housing 5 that opens forward (left side in FIG. 1) is accommodated, and a cylindrical barrel 7 that accommodates the striking mechanism 8 is connected to the opening of the crank housing 5. A handle 9 is connected to the rear of the motor housing 2.

  The output shaft 4 of the motor 3 is supported by a ball bearing 10 provided on the lower surface of the crank housing 5 and penetrates the crank housing 5 from below, and a gear 11 provided on the upper portion of the crankshaft 6 behind the output shaft 4. Meshed. The crankshaft 6 is pivotally supported by a ball bearing 14 serving as a bearing in which a lower intermediate portion of the gear 11 is positioned at a fitting position in the fitting recess 13 of the crank housing 5 by a bearing retainer 12. In the through hole 15 of the crank housing 5, it is supported by a needle bearing 16. That is, here, the gear housing that supports the output shaft 4 is integrated with the crank housing 5. An eccentric pin 17 projects from the upper surface of the gear 11 and is connected to the piston 20 of the striking mechanism 8 by a connecting rod 18.

  The striking mechanism 8 accommodates the piston 20 in a cylinder 19 held behind the barrel 7 so as to be movable back and forth, and accommodates a striking element 22 in the front thereof via an air chamber 21 so as to be movable back and forth. A bit holder 25 is inserted at the front end of the tool holder 23 at the front end of the tool holder 23 in a known configuration in which a meson 24 is accommodated in a tool holder 23 held in front of the barrel 7 in front of the barrel 7. An operation sleeve 26 is provided for preventing the slipping off and releasing it.

  As shown in FIG. 2, the bearing retainer 12 is a U-shaped plate body in a plan view, and is output in a posture in which a pair of left and right pressing portions 26 and 26 are directed rearward under the opening of the crank housing 5. It passes through the upper surface of the ball bearing 14 so as to sandwich the shaft 4 and the crankshaft 6. On both sides near the front end of the bearing retainer 12, semi-circular cutouts 27 and 27 are formed at positions where they do not overlap with the gear 11 and the ball bearing 14 in a plan view. Each pressing portion 26 is clamped and fixed between the receiving seat 28 and the head of the bolt 29 by screwing bolts 29 into receiving seats 28 formed on the bottom surface of the crank housing 5.

  On the other hand, the front ends of the pressing portions 26, 26 are locked to locking grooves 30 that are recessed in the left-right direction on the rear inner surface of the crank housing 5. Therefore, the bearing retainer 12 is fixed to the crank housing 5 at two locations, front and rear, with the bolt 29 and the locking groove 30, and the ball bearing 14 is fitted into the fitting recess 13 by pressing the upper surface of the bearing retainer 12. Will be positioned.

  The opening of the crank housing 5 is formed with a tapered portion 31 that expands toward the front, and a ring-shaped washer 32 is provided at a step portion 33 formed behind the tapered portion 31. The washer 32 is inserted into the opening of the crank housing 5 from the front in a vertical direction, and is guided by the tapered portion 31 to be fitted into the stepped portion 33. In the fitted state, the lower end of the washer 32 is a bearing retainer. The front surface of the cylinder 19 abuts against the rear end of the cylinder 19.

In the electric hammer 1 configured as described above, when the crankshaft 6 is assembled to the crank housing 5, the ball housing 14 and the needle bearing 16 at the lower end of the crankshaft 6 are respectively attached to the crank housing 5. Is inserted into the crank housing 5 from an upper opening that can be opened and closed by a lid, and the crankshaft 6 is pushed in from above the fitting recess 13 so that the needle bearing 16 is inserted into the through hole 15 and the ball bearing 14 is Each is fitted into the fitting recess 13.
Next, the bearing retainer 12 is inserted between the gear 11 and the ball bearing 14 from the opening in front of the crank housing 5 with the pressing portions 26, 26 first, and the ends of the pressing portions 26, 26 are inserted into the locking grooves 30. In the locked state, the bolts 29 and 29 are screwed on both sides of the bearing retainer 12. Then, the bearing retainer 12 is fixed to the crank housing 5 and the ball bearing 14 is positioned in the fitting recess 13. Thus, unlike the crankshaft 6 withdrawing / inserting from the upper side opening, the bearing retainer 12 is taken in / out through the opening in front of the crank housing 5.

  Then, after the washer 32 is pushed into the opening of the crank housing 5 from the front and fitted into the stepped portion 33, the barrel 7 assembled with the striking mechanism 8 is assembled to the crank housing 5, and the rear end of the cylinder 19 becomes the washer 32. The washer 32 is abutted and fixed at the fitting position. Thereby, the front end of the bearing retainer 12 is pressed by the washer 32.

  Thus, according to the electric hammer 1 of the said form, the positioning of the ball bearing 14 in the crank housing 5 is arrange | positioned between the ball bearing 14 and the gear 11, and is a plate-shaped bearing retainer fixed to the crank housing 5. 12 is a procedure for assembling the bearing retainer 12 after assembling the crankshaft 6 and the ball bearing 14 to the crank housing 5, and simplifies the structure related to assembling the crankshaft 6 and improves assemblability. Can do. Moreover, since the bearing retainer 12 also has a simple plate shape, it leads to space saving and cost reduction.

In particular, here, the bearing retainer 12 is screwed to the crank housing 5 at a position that does not overlap the gear 11 and the ball bearing 14 in plan view, so that the assembly of the bearing retainer 12 in the crank housing 5 can be performed more easily. .
Further, the bearing retainer 12 is formed in a U-shape in plan view including a pair of left and right pressing portions 26 and 26 that pass through the upper surface of the ball bearing 14 with the crankshaft 6 interposed therebetween, so that the ball bearing 14 can be reliably positioned. The bearing retainer 12 can be obtained easily.
Further, since the locking groove 30 in which the tips of the pressing portions 26 and 26 are locked is formed in the crank housing 5, the pressing portions 26 and 26 can be easily fixed using the crank housing 5. Leads to further improvement.

  In addition, the structure of a bearing retainer is not limited to the said form, It can change suitably. For example, as shown in FIGS. 3 and 4, the bearing retainer 12 a may be formed in an L shape integrally formed with a rising portion 34 corresponding to a washer at the front end. In this way, when the rising portion 34 is fitted from the tapered portion 31 to the stepped portion 33 when the bearing retainer 12a is inserted between the gear 11 and the ball bearing 14, the rising portion 34 causes the bearing retainer 12a to be fitted. The front end of the crank housing 5 is positioned at a position where it abuts against the lower surface of the opening of the crank housing 5, and the same effect as in the above embodiment can be obtained. However, in this case, the front end of the bearing retainer 12a is guided by the taper portion 31 by the integral rising portion 34 and positioned at the stepped portion 33, so that the bearing retainer 12a can be fixed only by the crank housing 5. The screwing by etc. can be omitted. Therefore, compared with the said form, there exists an advantage that a number of parts decreases and an assembly property becomes more favorable.

  In addition, the bearing is not limited to a ball bearing, but may be another type such as a needle bearing or a bearing metal. The striking tool may be a type in which the striking mechanism does not have an intermediate element and directly strikes a bit with a striking element. The present invention can be applied to any hammer drill or the like in which a rotation mechanism of the tool holder is provided by an intermediate shaft that is meshed with the output shaft separately from the crankshaft.

It is a longitudinal cross-sectional view of an electric hammer. It is a top view of the crankshaft part in a crank housing. It is a partial longitudinal cross-sectional view of the electric hammer which shows the example of a change of a bearing retainer. It is a top view of the crankshaft part in a crank housing.

Explanation of symbols

  1 .... electric hammer 2 .... motor housing 3 .... motor 4 .... output shaft 5 .... crank housing 6 .... crankshaft 8 .... striking mechanism 10,14 .... ball bearing 11 ..Gear, 12 ..Bearing retainer, 13 ..Fitting recess, 17 ..Eccentric pin, 19 ..Cylinder, 23 ..Tool holder, 26 ..Pressing portion, 29 ..Bolt, 30. Groove, 31 ... taper, 32 ... washer.

Claims (5)

The crankshaft is pivotally supported by a bearing positioned in the crank housing, the rotation of the output shaft of the motor is transmitted to a gear provided above the bearing in the crankshaft, and the eccentricity provided at the upper end of the crankshaft. A striking tool in which a pin is connected to a piston of a striking mechanism provided on the front side via a connecting rod,
A striking tool characterized in that positioning of the bearing in the crank housing is performed by a plate-shaped bearing retainer that is disposed between the bearing and the gear and is fixed to the crank housing.   The impact tool according to claim 1, wherein the bearing retainer is screwed to the crank housing at a position that does not overlap the gear and the bearing in plan view.   The front of the crank housing is connected to a cylindrical barrel that houses the striking mechanism, and forms an opening having a tapered portion that expands toward the front, while the front of the bearing retainer has a taper of the opening. The striking tool according to claim 1, further comprising a rising portion that is fitted to a portion and positions the front end of the bearing retainer.   4. The impact according to any one of claims 1 to 3, wherein the bearing retainer has a U-shape in a plan view including a pair of left and right pressing portions that pass through the upper surface of the bearing across the crankshaft. tool.   The impact tool according to claim 4, wherein a locking groove for locking a tip of the pressing portion is formed in the crank housing.

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