JP2008155369A - Electric hammer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology useful for improving overall performance of an electric hammer, such as weight reduction, appearance, and cost control, while securing vibration damping ability of the electric hammer. <P>SOLUTION: The electric hammer 101 is composed of a hammer bit 129, a driving motor 121, a crank mechanism 123 which drives an impact element 128 by converting output rotation of the driving motor 121 into linear motion in a longitudinal axis direction of the hammer bit 129, and a counter weight 201 which is detachably mounted on the crank mechanism 123 and performs vibration damping of the impact element 128. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vibration damping technique in an electric hammer that drives a hammer bit at a constant cycle such as a hammer or a hammer drill.

  Japanese Utility Model Laid-Open No. 51-6583 (Patent Document 1) discloses a configuration of a hammer provided with a vibration damping device. In this conventional hammer, a configuration is disclosed in which a counterweight driven by the crank arm mechanism is disposed in an upper region of the crank arm mechanism for linearly moving a striker that imparts a striking force to the hammer bit. . The counterweight is configured to reciprocate in the gear housing so as to face the striker driven by the crank arm mechanism, and the counterweight moves in the direction of the long axis of the hammer bit generated when the hammer is driven. It is comprised so that the strong vibration of may be suppressed effectively.

By the way, the counterweight needs to have an appropriate size so as to appropriately suppress a large vibration at the time of driving the hammer, and a space for accommodating such a dynamic vibration absorber inevitably requires an appropriate size. In addition, there is a case where it is not necessary to mount the counterweight on the electric hammer depending on the work situation, the user's request, and the like, and there is a demand to further devise the construction technique of the counterweight in the electric hammer.
Japanese Utility Model Publication No. 51-6583

  The present invention has been made in view of the above points, and provides a technique that contributes to improving overall performance such as weight reduction, appearance, and cost control while ensuring vibration damping in an electric hammer. With the goal.

In order to achieve the above object, the invention described in each claim is configured.
According to the first aspect of the present invention, the hammer main body, the hammer bit disposed in the tip region of the hammer main body, the drive motor disposed in the hammer main body , and the drive motor disposed in the hammer main body. a crank mechanism for the rotary output drives the striking element is converted into a linear motion in the axial direction of the hammer bit, disposed within the hammer main body portion, a counterweight performing damping of the striking element is disposed within the hammer main body portion And an electric hammer having a counterweight driving means for driving the counterweight . The electric hammer is not only a hammer hammer that performs a hammer function by linearly moving in the long axis direction, but in addition to the hammer function, a drill hammer type in which the hammer bit rotates in its circumferential direction to perform a drill function is suitable. Included. The crank mechanism drives the striker by converting the rotational output of the drive motor into a linear motion in the long axis direction of the hammer bit. The counterweight controls the striker. Specifically, it moves linearly against the striker driven linearly by the crank mechanism, thereby canceling each other's kinetic energy (momentum) and effectively suppressing the vibration of the entire electric hammer. It is.

The crank mechanism according to the present invention is rotatably supported by a hammer body through a bearing, and revolves around the rotation center of the shaft at a position shifted from the rotation center of the shaft that is rotationally driven by a drive motor. An eccentric pin, and one end side is attached to the eccentric pin, and the other end side is attached to the hammer bit striking mechanism, thereby linearly moving the hammer bit striking mechanism and thereby a crank arm for driving the striking element. . The counterweight drive means has a counterweight drive crank that is attached to the eccentric pin and is rotated via the eccentric pin, and the counterweight is linearly moved in the longitudinal direction of the hammer bit by the counterweight drive crank. It is comprised so that it may reciprocate in the shape. The counterweight driving crank is disposed opposite to the shaft with the crank arm interposed therebetween, and is rotatably supported by the hammer body through a bearing .
According to the present invention, with the above configuration, the shaft and the eccentric pin constituting the crank mechanism and the counterweight driving crank constituting the counterweight driving means are formed as an integral rigid body. Is supported by the bearing, and the crank for driving the counterweight is supported by the bearing, so that stable support for rotational driving is realized.

(Invention of Claim 2)
According to a second aspect of the present invention, in the electric hammer according to the first aspect, the counterweight driving crank is engaged with the eccentric pin and is relatively slidable with the eccentric pin. The configuration has an allowable eccentric pin sliding groove. According to the present invention, the counterweight driving crank for driving the counterweight is engaged with the eccentric pin provided in the crank mechanism for driving the crank arm via the eccentric pin sliding groove, The eccentric pin relatively slides in the groove. By this relative sliding operation, the counterweight driving crank is driven through the revolving motion of the eccentric pin accompanying the rotation of the shaft. In addition, the configuration in which the eccentric pin is engaged with the eccentric pin sliding groove makes it possible to roughly set the accuracy between the two, and it is possible to improve the cost during manufacturing and the workability during assembly. Become.

(Invention of Claim 3)
According to the invention described in claim 3, the dynamic vibration absorber is further detachably attached to the electric hammer described in claim 1 or 2. This dynamic vibration absorber has a main body part, a weight accommodated in the main body part, and an elastic element that connects the weight to the main body part. It is sufficient that the weight is connected to the main body portion by at least an elastic element, and a configuration in which the weight is connected to the main body portion by a damping element is also included. According to the present invention, in addition to the above-described vibration suppression by the counterweight in addition to the above-described vibration suppression by the dynamic vibration absorber, the vibration that cannot be completely controlled by the counterweight is moved in addition to the vibration suppression by the counterweight described above. It is possible to further suppress vibrations by using a vibration absorber and take all possible countermeasures against vibrations in electric hammers.

  In addition, the dynamic vibration absorber is a passive vibration control mechanism in which a vibration suppression operation is started in response to vibration of the vibrating body, so that not only the vibration control for the crank mechanism but also the crank mechanism and the counterweight. This effectively works against vibration suppression when the canceling operation does not match. In addition, the dynamic vibration absorber in the present invention is detachably attached to the electric hammer in the same manner as the counterweight, so that the dynamic vibration absorber can be operated according to the situation such as the work mode or the necessity of dynamic vibration suppression. It is possible to appropriately switch between the case where the vibration is suppressed by being attached to the tool body and the case where the operation is performed using the electric hammer having a light and slim appearance by removing the dynamic vibration absorber from the electric hammer. In addition, it is possible to rationally control the cost and convenience of the electric hammer by leaving the operator to decide whether to set the dynamic vibration absorber while ensuring the possibility of mounting the dynamic vibration absorber. It becomes. In addition, it is preferable to attach and detach the dynamic vibration absorber through a crank cap or an opening formed above the crank mechanism as in the case of attaching and detaching the counterweight.

  By the way, as described above, the counterweight according to the present invention is configured to exhibit a damping function for the striker by linearly moving in opposition to the linear motion of the striker driven by the crank mechanism. On the other hand, the driving mode of the electric hammer is not limited to a mode in which a predetermined work is performed on the workpiece by the hammer bit, that is, a mode in which a load is applied to the hammer bit (loaded driving state), and the hammer bit performs the work. There is a mode in which a load is not applied to the hammer bit (no-load drive state). For this reason, the counterweight originally provided for damping the driver in the loaded drive state may become a vibration source in the no-load drive state.

  In the present invention, in the case where the counterweight whose drive timing is set in accordance with the loaded drive state in this way becomes a vibration source in the no-load drive state, the dynamic vibration absorber effectively exerts a damping action. It will be. That is, the dynamic vibration absorber according to the present invention exerts an effect on damping of the striker in cooperation with the counterweight adjusted in timing in accordance with the load driving state in the load driving state, In the no-load driving state, it can be configured to perform not only the vibration control of the striker but also the vibration control action on the counterweight.

That is,
(Aspect 1)
"Electric hammer according to claim 3 ,
The counterweight is set to linearly move in an opposing manner corresponding to the linear movement of the striker when a load acts on the hammer bit,
The electric hammer, wherein the dynamic vibration absorber is set so as to suppress vibration based on linear motions of the striker and the counterweight when no load is applied to the hammer bit. "

  As a result, in the loaded drive state, the counterweight and the dynamic vibration absorber cooperate for vibration control of the striker, and in the no-load drive state, the dynamic vibration absorber acts on the striker and the counterweight. A reasonable vibration control mechanism is ensured.

  According to the present invention, there is provided a technique that contributes to improving overall performance such as weight reduction, appearance, and cost control while ensuring vibration damping in an electric hammer.

  Hereinafter, a hammer according to an embodiment of the present invention will be described in detail with reference to the drawings. 1 shows the configuration of the hammer 100 to which only the counterweight 201 is attached, and FIG. 2 shows the configuration of the hammer 101 to which the counterweight 201 and the dynamic vibration absorber 301 are attached. Since the hammers 100 and 101 use the same elements for the elements other than the dynamic vibration absorber 301, they will be described with common reference numerals in the drawings.

As shown in FIG. 1, the hammer 100 according to the present embodiment generally includes a motor housing 105 and a gear housing 107 as a main body portion 103 that forms the outline of the hammer 100. A hammer bit fastening portion 111 for fastening the hammer bit 129 to the main body portion 103 is provided at the distal end region of the gear housing 107. A hand grip 113 is provided on the rear end side of the motor housing 105 and the gear housing 107.

  A drive motor 121 is disposed in the motor housing 105. An opening 110 in which a crank cap 109 is disposed is formed on the upper surface of the gear housing 107. A counterweight 201 or a dynamic vibration absorber 301 (see FIG. 2) described later is attached to and detached from the main body 103 through the opening 110.

  Further, in the gear housing, a motion conversion mechanism 123 for converting the rotation output of the drive motor 121 into a linear motion of the hammer bit 129 in the long axis direction, a cylinder mechanism 125 driven via the motion conversion mechanism 123, a cylinder A striking element 127 mainly composed of a striking element 128 that applies an impact force in the major axis direction to the hammer bit 129 by a striking force obtained by the mechanism 125 is appropriately disposed.

  A counterweight 201 is detachably disposed in a region directly below the opening 110 on the upper side of the motion conversion mechanism 123 in the hammer 100. The counterweight 201 is used to control the vibration in the long axis direction of the hammer bit 129 generated in the motion conversion mechanism 123.

  On the other hand, in the hammer 101 shown in FIG. 2, in addition to the configuration of the hammer 101, a dynamic vibration absorber 301 is detachably disposed in a region further above the counterweight 201 and directly above the opening 110. The dynamic vibration absorber 301 dampens the vibration in the major axis direction of the hammer bit 129 generated in the motion conversion mechanism 123 in cooperation with the counterweight 201 when the hammer 101 is driven with a load. Furthermore, the dynamic vibration absorber 301 is set so as to exhibit a vibration damping action not only for vibration in the motion conversion mechanism 123 but also for vibration caused by the counterweight 201 when the hammer 101 is driven without load.

  FIG. 3 shows a detailed configuration of the main part of the hammer 101 centering on the counterweight 201 and the dynamic vibration absorber 301. The hammer 100 shown in FIG. 1 has the same configuration as the hammer 101 shown in FIG. 2 except for the presence or absence of the dynamic vibration absorber 301. Therefore, in order to avoid duplication of explanation, the explanation and illustration regarding the hammer 101 will be used for the explanation and illustration of the detailed configuration of the main part relating to the hammer 100.

  As shown in FIG. 3, the hammer 101 serves as a motion conversion mechanism 123, a transmission gear 135 that meshes with and engages with a gear portion 133 formed on the output shaft 131 of the drive motor 121, and the transmission gear 135. The gear shaft 137 that is integrally formed and rotated, the upper bearing 138a and the lower bearing 138b that support the gear shaft 137, and the rotational center of the transmission gear 135 (that is, the rotational center of the gear shaft 137) are disposed. An eccentric pin 139 and a crank arm 143 having one end connected to the eccentric pin 139 via an eccentric pin bearing 141 are provided. The other end side of the crank arm 143 is connected to a driver element 145 disposed in the cylinder 147. The driver 145 slides in the cylinder 147 to drive a striker (not shown) in a straight line through the action of a so-called air spring, thereby generating an impact load on the hammer bit 129 shown in FIG.

  Furthermore, in this embodiment, the counter weight 201 and the counter weight driving means 203 are provided above the motion conversion mechanism 123. The counterweight drive means 203 is provided in a counterweight drive crank 205 that is connected by fitting an eccentric pin 139 into the eccentric pin guide hole 209 and a front end region (left end region in the figure) of the counterweight drive crank 205. The crank pin 207 is integrally formed. The counterweight drive crank 205 is configured to be rotatable in a horizontal plane while being pivotally supported on the inner peripheral surface of the crank cap 109 via a bearing 206.

  A dynamic vibration absorber 301 is disposed further above the counterweight 201 and the counterweight driving means 203 described above. The outer periphery of the dynamic vibration absorber 301 is configured by a cylindrical body 303 formed in a long hollow shape. The cylinder 303 corresponds to the “main body” of the dynamic vibration absorber in the present invention. A weight 305 extending in the major axis direction of the cylinder 303 is disposed in the cylinder 303. The weight 305 has a large-diameter portion 313 and a small-diameter portion 315, and biasing springs 317 are attached to the left and right end regions of the large-diameter portion 313, respectively. The urging spring 317 corresponds to the “elastic element” in the present invention, and gives elastic force to the weight 305 with the cylinder 303 when the weight 305 moves in the long axis direction of the cylinder 303. .

  Both the counterweight 201 and the counterweight driving means 203 are disposed through the opening 110 of the hammer 101, and the dynamic vibration absorber 301 is disposed in a region immediately above the opening 110. For this reason, the counterweight 201, the counterweight driving unit 203, and the dynamic vibration absorber 301 are configured to be easily detachable from the hammer 101. As described above, the counterweight driving means 203 is configured to be able to be removed above the opening 110 together with the crank cap 109, and the efficiency of the attaching / detaching work is ensured. The eccentric pin 139 of the transmission gear 135 is only loosely fitted into the eccentric pin guide hole 209 in the counterweight drive crank 205 from the lower side in a non-fixed manner, and obstructs the detachability of the counterweight drive means 203. Not what you want.

  The hammer 101 according to the present embodiment is configured as described above. Next, the operation and usage method of the hammer 101 will be described. When the drive motor 121 is driven, the rotational output of the drive motor 121 is transmitted to the transmission gear 135 via the output shaft 131 and the gear portion 133 of the output shaft 131. As a result, the transmission gear 135 is rotationally driven together with the gear shaft 137. The rotation of the transmission gear 135 causes the eccentric pin 139 to revolve around the rotation axis of the gear shaft 137, whereby the crank arm 143 reciprocates in the left-right direction in the figure, and the driver 145 linearly reciprocates in the bore of the cylinder 147. Exercise.

  As the driver element 145 moves linearly, a striker (not shown) collides with an impact bolt (not shown) at a speed higher than the speed of the driver element 145 by the action of a so-called air spring. The bit 129 (see FIG. 2) linearly moves forward at a high speed, and a hammering operation on a workpiece (not shown) is performed.

  In the present embodiment, the counterweight 201 is driven by utilizing the rotating operation of the eccentric pin 139 in the motion conversion mechanism 123 shown in FIG. Regarding the drive mode of the counterweight 201, FIG. 4 schematically shows the relationship among the eccentric pin 139, the counterweight drive crank 205, the eccentric pin guide hole 209, the crankpin 207, and the counterweight 201. As described above, when the eccentric pin 139 rotates around the rotation axis of the gear shaft 137, the eccentric pin guide hole 209 receives the rotational movement of the eccentric pin 139, thereby rotating the counterweight drive crank 205. Driven. Then, the crank pin 207 provided eccentrically on the counterweight drive crank 205 rotates around the eccentric pin 139.

  In addition, since the eccentric pin 139 is configured to be loosely engaged with the eccentric pin guide guide hole 209, it is not necessary to set the assembly accuracy of both of them so severely, and the cost and assembly performance of the hammer configuration can be improved. Is possible.

  On the other hand, the counterweight 201 is formed with a long hole-shaped crank pin guide hole 211 extending in a direction (vertical direction in the drawing) intersecting with the major axis direction. Only the movement component of the counterweight 201 in the major axis direction is transmitted to the counterweight 201. As a result, the counterweight 201 linearly moves in the long axis direction (left-right direction in the figure) directly opposite to the circular motion of the eccentric pin 139, in other words, directly opposite to the linear motion of the striker 128. Become.

  Thus, when the striker 128 linearly moves by reciprocating linearly in the longitudinal direction of the hammer 101 (left and right in FIG. 3), the crank arm 143 reciprocates so as to face the linear movement of the striker 128. As a result, the dynamic vibration of the striker 128 is reasonably controlled. Furthermore, in the present embodiment, in addition to the vibration damping operation by the counterweight 201, the dynamic vibration absorber 301 further provides a vibration damping function for the dynamic vibration of the striker 128. Therefore, it is possible to suppress the vibration when the hammer 101 is driven to a considerable extent, and to improve the usability and silence of the hammer 101.

  By the way, the counterweight 201 in the present embodiment is configured to exhibit a vibration control function by linearly moving in an opposing manner with respect to the linear motion of the striker 128, but the counterweight 201 is in a loaded drive state. Is set so as to oppose the linear motion of the striker 128. For this reason, the counterweight 201 effectively exerts the vibration damping action in the loaded drive state, but in the no-load drive state, the counterweight 201 that should be set for damping in the loaded drive state is Conversely, it may become a vibration source.

  In the present embodiment, in the no-load driving state, even if the counterweight 201 is a vibration source, the above-described dynamic vibration absorber 301 effectively exerts a vibration damping action against such vibration. That is, in the hammer according to the present embodiment, when the dynamic vibration absorber 301 is in a loaded drive state, the hammer 128 cooperates with the counterweight 201 whose phase is adjusted in accordance with the loaded drive state. In addition, in the no-load driving state, it is possible to perform not only the vibration control of the striker 128 but also the vibration control action on the counterweight 143.

  Moreover, in the present embodiment, both the counterweight 201 and the counterweight driving means 203 can be easily removed from the hammer 101 through the opening 110 formed above the crank cap 109, and the dynamic vibration absorber 301 is further removed. Can be easily detached from the upper part of the opening 110, so that it is possible to easily determine whether to attach or detach each damping element according to the situation such as the work mode or the necessity of dynamic damping. It is possible to rationally adjust factors such as cost, convenience, external dimensions, and weight.

(Example of change)
A hammer 102 according to a modification of the present embodiment will be described with reference to FIG. This hammer 102 is a modified example relating to the connection mode between the above-mentioned eccentric pin 139 and the counterweight driving means 203. Accordingly, the elements equivalent to the hammers 100 and 101 are illustrated with the same reference numerals, and the description thereof is omitted for convenience.

  As shown in FIG. 5, the eccentric pin 139 provided on the transmission gear 135 is detachably fixed to the counterweight drive crank 205 via a fixed pin 139a. The counterweight drive crank 205 that forms the main part of the counterweight drive means 203 is configured to be rotatable with respect to the crankcap 109 via a bearing 206 in the lower region of the opening 110. As the counterweight drive crank 205 rotates, the counterweight 201 reciprocates in the long axis direction (left and right direction in FIG. 5) of the hammer 102, thereby exerting a damping action against the reciprocating motion of the crank arm 143.

  By the way, in this modified example, as a result of the eccentric pin 139 and the counterweight drive crank 205 being fixed by the fixed pin 139a, the transmission gear 135, the gear shaft 137, the eccentric pin 139, the fixed pin 139a, and the counterweight drive crank 205 are The whole is rotated as an integral rigid body. Therefore, from the viewpoint of ensuring the stability of the rotational drive, it is sufficient to support the upper and lower portions of the integral rigid body appropriately. In this modified example, an upper bearing 206 and a lower bearing 138a are employed as pivot support points for the integrated rigid body. As described above, in this modified example, it is not necessary to separately set the shaft support portion for the transmission gear 135 and the gear shaft 137 and the shaft support portion for the counterweight drive crank 205, and the corresponding height. It is sufficient to support an integral rigid body having dimensions. Therefore, even if the assembly accuracy of each member element is set to be rough to some extent, it becomes difficult for rotational drive to occur, and a rational configuration is provided for both simplification of the internal mechanism and stable support of the rotational drive element. It is possible.

  In addition, when each element is removed through the opening 110, it is sufficient to release the fixing between the eccentric pin 139 and the counterweight drive crank 205 by the fixing pin 139a, thereby further improving the detachability of the vibration damping mechanism. It becomes possible.

It is sectional drawing which shows the whole structure of the hammer 100 which concerns on this Embodiment. It is sectional drawing which shows the whole structure of the hammer 101 which concerns on this Embodiment. 2 is a partial cross-sectional view showing a configuration of a main part of the hammer 101. FIG. It is a schematic diagram which shows the structure of a counterweight drive means. It is a fragmentary sectional view which shows the structure of the hammer 102 which concerns on the example of a change.

Explanation of symbols

100, 101, 102 Hammer 103 Main body part 105 Motor housing 107 Gear housing 109 Crank cap 110 Opening part 111 Hammer bit fastening part 113 Hand grip 121 Drive motor 123 Motion conversion mechanism 125 Cylinder mechanism 127 Strike element 128 Strike element 129 Hammer bit 131 Output shaft 133 Gear portion 135 Transmission gear 137 Gear shaft 138a, b Gear shaft bearing 139 Eccentric pin 141 Eccentric pin bearing 143 Crank arm 145 Drive element 147 Cylinder 201 Counter weight 203 Counter weight driving means 205 Counter weight driving crank 206 For crank Bearing 207 Crank pin 209 Eccentric pin guide hole 211 Crank pin guide hole 301 Dynamic vibration absorber 303
305 Weight 313 Large diameter portion 315 Small diameter portion 317 Biasing spring (elastic element)

Claims (3)

With Hammerbit,
A drive motor;
A crank mechanism that converts a rotational output of the drive motor into a linear motion in the longitudinal direction of the hammer bit and drives the striker; and a counterweight that is detachably attached to the crank mechanism and controls the striker. An electric hammer characterized by comprising: The electric hammer according to claim 1, further comprising:
An electric hammer comprising a main body, a weight housed in the main body, and a dynamic vibration absorber having an elastic element connecting the weight to the main body. The electric hammer according to claim 1 or 2,
The crank mechanism is
A gear that is rotationally driven by the output shaft of the drive motor;
An eccentric pin fixed to the gear eccentrically;
One end side is attached to the eccentric pin, and the other end side is attached to the hammer bit striking mechanism, so that the hammer bit striking mechanism is linearly moved, and thereby a crank arm that drives the striking element,
An electric hammer characterized in that the counterweight is detachably attached to the eccentric pin that revolves by rotation of the gear and is linearly moved by a counterweight driving means that linearly moves in the hammer bit long axis direction. .

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