JP2006142459A - Hammer drill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hammer drill capable of miniaturizing, reducing the weight and the cost, and improving operationality and durability by simplifying the structure of a switching mechanism and reducing the number of parts. <P>SOLUTION: The hammer drill 1 is equipped with a hammering mechanism for transmitting a striking force to a tip end tool 26 by a pressure change of an air chamber 24 partitioned in a cylinder 17 through a hammer 21, and a rotary transmission mechanism part which transmits the rotation of the motor 8 to the cylinder 17 and drives to rotate the cylinder 17 and the tip end tool 26 engaging with it. The hammer drill 1 is provided with an air intake hole 25 communicating with the air chamber 24 and the outside air formed on the cylinder 17, and the switching mechanism capable of switching between a first mode enabling to close the air intake hole 25 according to the movement of the tip end tool 26 to the hammer 21 side and a second mode always opening the air intake hole 25. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hammer drill that has both a hammer and a drill function, provided with a striking mechanism that applies a striking force to a tip tool and a rotation transmission mechanism that transmits rotational force to the tip tool and rotationally drives it.

  The operation mode of a hammer drill having a striking mechanism portion and a rotation transmission mechanism portion includes a striking / rotating mode in which the tip tool is rotated while applying a striking force to the tip tool, a rotation mode in which only the tip tool is rotated, and a tip. There are three types of impact modes that only apply impact force to the tool, but these operation modes are switched according to the type of work by the operation mode switching mechanism.

  By the way, as an operation mode switching mechanism, what was proposed by patent document 1, for example is known. This operation mode switching mechanism employs a system in which a gear and a clutch mechanism are provided in each of the impact mechanism unit and the rotation transmission mechanism unit, and the operation mode is switched by connecting and disconnecting the transmission of the rotational force from the motor by the clutch mechanism. .

JP 2002-192481 A

  However, the conventional operation mode switching mechanism has a problem in that the structure is complicated and the number of parts is large, so that the hammer drill body is large and expensive, and the weight is large and the operability is poor.

  The present invention has been made in view of the above problems, and the object of the present invention is to reduce the size and weight, reduce costs, improve operability and durability by simplifying the structure of the switching mechanism and reducing the number of parts. It is to provide a hammer drill that can.

To achieve the above object, the invention according to claim 1 slidably fits an impactor in a cylinder, converts the rotation of a motor as a drive source into a reciprocating motion of a piston in the cylinder, A striking mechanism for transmitting a striking force to the tip tool through the striking element by pressure fluctuations in an air chamber defined by the piston and the striking element in the cylinder;
A rotation transmission mechanism that transmits the rotation of the motor to the cylinder via a gear and rotationally drives the cylinder and the tip tool engaged therewith;
In a hammer drill comprising
A first mode in which an intake hole for communicating the air chamber and the outside air is formed in the cylinder, and the breathing hole can be closed according to the movement of the tip tool toward the striker; A switching mechanism that enables switching to the second mode to be opened is provided.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, the switching mechanism is capable of switching the mode by regulating an amount of movement of the tip tool toward the striker. .

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the switching mechanism is externally fitted to the cylinder so as to be movable, and interlocked with the movement of the tip tool toward the striker. It has a sleeve which can open and close the breathing hole, and the mode can be switched by restricting movement of the sleeve.

  According to a fourth aspect of the present invention, in the first aspect of the present invention, the cylinder can be moved in accordance with the movement of the tip tool toward the striker side, and the switching mechanism can control the amount of movement of the cylinder. The mode can be switched by regulating.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the switching mechanism has a rotatable cam, and the mode can be switched depending on the rotational position of the cam. It is characterized by being.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the switching mechanism can be switched to a third mode in which the rotational drive of the cylinder is released. To do.

  A seventh aspect of the present invention is the invention according to any one of the first to sixth aspects, wherein the operation mode of the tip tool can be switched between a rotation / striking mode, a rotation mode, and a striking mode by the switching mechanism. It is characterized by that.

  According to an eighth aspect of the present invention, in the first aspect of the present invention, the rotation transmission mechanism portion is provided with the gear rotatably on the outer periphery of the cylinder and slidably fitted on the outer periphery of the cylinder. And the coupling member is engaged with and disengaged from the gear by operating the switching member of the switching mechanism.

  The invention according to claim 9 is the invention according to claim 8, wherein the switching member is provided with an eccentric pin, and the connecting member is moved by the eccentric pin by a rotation operation of the switching member, and this is moved to the gear. It is characterized by making it disengage with respect to.

  According to the first and second aspects of the present invention, when the breathing hole is closed by switching to the first mode by the switching mechanism, the air chamber in the cylinder is substantially sealed, and the pressure fluctuation inside the tip is passed through the striker. When the impact mode is selected as the operation mode and the breathing hole is opened by switching to the second mode, the air chamber in the cylinder communicates with the outside air through the breathing hole. The pressure change does not occur and the operation mode can be switched to an operation mode other than the striking mode, but the switching mechanism is arranged around the cylinder as a simple configuration for opening and closing the breathing hole. The number of parts can be reduced, and the hammer drill can be reduced in size and weight, cost can be reduced, operability and durability can be improved.

  According to the invention of claim 3, the switching mechanism restricts the movement of the sleeve, and according to the invention of claim 4, the switching mechanism is configured to switch the mode by restricting the movement amount of the cylinder. A switching mechanism can be arranged around the cylinder to simplify the structure and reduce the number of parts.

  According to the fifth aspect of the present invention, the mode can be switched with good operability by the turning operation of the cam provided in the switching mechanism.

  According to the sixth aspect of the present invention, when the mode is switched to the third mode by the switching mode, the cylinder and the tip tool mounted on the cylinder can be idled. Can be easily changed.

  According to the seventh aspect of the invention, the hammer drill functions as a hammer and a drill if the rotation / blow mode is selected by the switching mechanism, and only functions as a drill if the rotation mode is selected, and the hammer mode is selected. It will only function as a hammer.

  According to the eighth aspect of the invention, the operation mode (rotation mode) is switched by connecting / disconnecting transmission of the motor rotation to the cylinder and the tip tool by engaging / disengaging the connecting member with the gear by operating the switching member. Therefore, it is possible to simplify the structure and reduce the number of parts by concentrating the switching mechanism in the cylinder part. This makes the hammer drill smaller, lighter, lowers cost, operability and durability. Improvement can be achieved.

  According to the ninth aspect of the present invention, the switching member is rotated to move the connecting member by the eccentric pin, and the connecting member is engaged with and disengaged from the gear. ) Can be easily switched.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
FIG. 1 is a side view of a hammer drill according to the present invention. A hammer drill 1 shown in the drawing has three modes, that is, a rotation / blow mode, a rotation mode, and a blow mode as operation modes. A striking mechanism, a rotation transmission mechanism, and a switching mechanism are incorporated.

  A handle 3 is provided at the rear end of the housing 2 (the right end in FIG. 1). The handle 3 is provided with an ON / OFF switch 4 and an electric cord 5 for power supply is connected thereto. Further, a dial-like switching member 6 for switching the operation mode is rotatably provided on the side portion of the housing 2, and a sub handle 7 is laterally (in front of FIG. 1) in front of the dial. Projected.

  Thus, a tip tool 26 (see FIG. 2), which will be described later, is attached to the tip of the hammer drill 1, and the tip tool 26 receives a striking force and / or a rotational force to perform a required operation.

  Next, details of the internal structure of the hammer drill 1 will be described with reference to FIGS.

  FIG. 2 is a side sectional view of the main part of the hammer drill, FIG. 3A is a side view of the switching member, and FIG. 2B is a bottom view of the switching member. In FIG. 2, the switching member 6 provided on the side portion of the housing 2 is illustrated in a state where the phase is shifted by 90 ° for convenience.

  The housing 2 includes a motor housing 2A and a cylinder case 2B attached to the upper portion of the motor housing 2A. A motor 8 as a drive source is accommodated in the motor housing 2A in a vertically placed state. A pinion 10 is integrally formed at the upper end of an output shaft (motor shaft) 9 extending upward of the motor 8.

  A crankshaft 11 and an intermediate shaft 12 are supported on both sides of the output shaft (motor shaft) 9 of the motor 8 so as to be vertical and rotatable. The crankshaft 11 and the intermediate shaft 12 are respectively supported. Gears 13 and 14 are respectively attached to the intermediate height positions, and these gears 13 and 14 mesh with the pinion 10 formed at the end of the motor shaft 9. The diameters of both gears 13 and 14 are set larger than that of the pinion 10. At the upper end of the crankshaft 11, a crankpin 15 is vertically and integrally installed at a position eccentric to the center of rotation, and a small-diameter bevel gear 16 is integrally formed at the upper end of the intermediate shaft 12. Yes.

  On the other hand, in the cylinder case 2 </ b> B extending in the horizontal direction, the cylinder 17 is horizontally disposed with both axial ends thereof rotatably supported by ball bearings 18 and metal bearings 19. The piston 20 and the striker 21 are slidably fitted. The piston 20 is connected to the crankpin 15 of the crankshaft 11 via a connecting rod 22, and one end of the connecting rod 22 is connected to the piston 20 via a piston pin 23.

  In the cylinder 17, an air chamber 24 is defined by the striker 21 and the piston 20, and a plurality of breathing holes 25 that open to the air chamber 24 are formed in the cylinder 17. Note that these breathing holes 25 selectively communicate the air chamber 24 and the outside air.

  Further, a detachable tip tool 26 is attached to the thinned tip portion of the cylinder 17, and the tip tool 26 can slide in the axial direction (front-rear direction) with respect to the cylinder 17 and rotate in the circumferential direction. Engaged impossible. An intermediate element 27 is fitted between the tip tool 26 in the cylinder 17 and the striker 21 so as to be slidable in the horizontal direction, and the end face in the axial direction of the intermediate piece 27 is the tip tool 26 and the striker 21. Are in contact with each end face.

  The end of the intermediate element 27 on the striking element 21 side is formed to have a smaller diameter than the intermediate part, and this end is formed in a central hole of an annular member 28 that is slidably fitted in the cylinder 17 in the horizontal direction. The tapered step portion 27 a formed between the end portion and the intermediate portion is in contact with one end surface of the annular member 28. Accordingly, the annular member 28 slides in the cylinder 17 together with the intermediate element 27 toward the striker 21 side (rear), but does not move with the intermediate element 27 toward the tip tool 26 side (forward), and only the intermediate element 27 is moved. Move alone. Further, a plurality of pins 29 as locking members are vertically inserted and held on the outer peripheral portion of the annular member 28, and the cylinder 17 has long holes 17 a that are long in the axial direction in which the pins 29 are engaged. Is formed. Therefore, the annular member 28 that holds the pin 29 can move in the axial direction (front-rear direction) within a range in which the pin 29 can slide in the long hole 17 a of the cylinder 17.

  On the other hand, two slide sleeves 30 and 31 are slidably fitted on the outer peripheral portion of the cylinder 17 in the front-rear direction, and a plurality of axially long front end inner peripheral portions of one (front side) slide sleeve 30 are provided. The engagement grooves 30a are formed, and the pins 29 are engaged with the respective engagement grooves 30a.

  Further, a rotation locking member 32 is disposed on the outer peripheral side of the other (rear) slide sleeve 31, and the rotation locking member 32 slides in the axial direction on the inner peripheral portion of the cylinder case 2B. The spline fitting is possible and non-rotatable in the circumferential direction, and is always urged rearward by a spring 33 that is compressed between the ball bearing 18 and the rear end surface of the switching member 6 as shown in the figure. Is in contact with the outer peripheral surface (cam surface) of the cam 6a.

  Here, the configuration of the switching member 6 is shown in detail in FIG. 3, and the switching member 6 is integrally formed with the cam 6a having the cam surface of the flow fill as shown in FIG. 3 (b). An eccentric pin 6b is integrally projected at a position eccentric from the rotation center of the switching member 6 on the end surface of the cam 6a.

  As shown in FIG. 2, a large-diameter bevel gear 34 is rotatably supported on the outer periphery of the rear end of the cylinder 17, and the bevel gear 34 has a small diameter formed at the upper end of the intermediate shaft 12. The bevel gear 16 meshes with the bevel gear 16. The bevel gear 34 is rotatably supported on the cylinder case 2B by the metal bearing 19 together with the rear end portion of the cylinder 17.

  A connecting member 35 is spline-fitted between the rotation locking member 32 and the bevel gear 34 on the outer periphery of the cylinder 17 so as to be slidable in the axial direction (front-rear direction) and not rotatable in the circumferential direction. The connecting member 35 is always urged rearward by a spring 36 which is contracted between the connecting sleeve 35 and the slide sleeve 31, and the step formed on the outer peripheral portion of the front end thereof is an eccentric pin 6 b of the switching member 6. Abut. A plurality of engagement claws 35a that selectively engage with a plurality of engagement claws 32a formed on the rear end surface of the rotation locking member 32 are formed at the front end portion of the connection member 35. A plurality of engagement claws 35b that selectively engage with a plurality of engagement claws 34a formed on the bevel gear 34 are formed at the rear end of the member 35 (see FIG. 5). Constitutes a dog clutch together with the rotation locking member 32 and the bevel gear 34.

  Thus, the gear 13, the crankshaft 11, the connecting rod 22, the cylinder 17, the piston 20, the striking element 21, the intermediate element 27, and the like described above constitute a striking mechanism unit, and the striking mechanism unit provides an output shaft of the motor 8. The rotation of the (motor shaft) 9 is converted into the reciprocating motion of the piston 20 and an impact force is applied to the tip tool 26.

  The gear 14, the intermediate shaft 12, the bevel gears 16 and 34, the connecting member 35, the cylinder 17 and the like constitute a rotation transmission mechanism, and the rotation transmission mechanism rotates the output shaft (motor shaft) 9 of the motor 8. Is transmitted to the tip tool 26 and the tip tool 26 is rotationally driven.

  Furthermore, the breathing hole 25, the annular member 28, the pin 29, the slide sleeves 30 and 31, the switching member 6, the connecting member 35, the rotation locking member 32 and the like constitute a switching mechanism.

  Next, the operation of the hammer drill having the above configuration will be described with reference to FIG. 2 and FIGS. 4 to 10 regarding 1) the rotation / blow mode, 2) the rotation mode, 3) each mode of the blow mode, and 4) neutral. 2 is a side cross-sectional view of the main part of the hammer drill in the rotation / blow mode. FIGS. 4, 5, and 6 are side cross-sectional views of the main part of the hammer drill in the rotation mode, the hit mode, and the neutral, respectively. 8, FIG. 9, and FIG. 10 are diagrams showing the positions of the cam and the eccentric pin of the switching member in the rotation / blow mode, rotation mode, hit mode, and neutral, respectively.

1) Rotation / blow mode:
The rotation / striking mode is a mode in which the tip tool 26 is rotationally driven while applying a striking force to the tip tool 26. When the switching member 6 is rotated and the rotation / striking mode is selected, the switching member 6 cam 6a and eccentric pin 6b are in the position shown in FIG. Therefore, at this time, as shown in FIG. 2, the connecting member 35 is connected to the bevel gear 34, both engaging claws 35b, 34a (see FIG. 5) are in the engaged state (clutch ON state), and the rear end face is The rotation locking member 32 that contacts the end surface (cam surface) of the cam 6a of the switching member 6 is in a state of being separated from the connecting member 35 (clutch OFF state) as shown in the figure.

  Thus, when the motor 8 is driven, the rotation of the output shaft (motor shaft) 9 is decelerated via the pinion 10, the gear 14, the intermediate shaft 12, and the bevel gears 16 and 34, and is connected to the bevel gear 34. Since it is transmitted to the cylinder 17 through the member 35, the cylinder 17 and the tip tool 26 attached to the tip of the cylinder 17 are rotationally driven, and the tip tool 26 functions as a drill.

  At the same time, the rotation of the output shaft (motor shaft) 9 of the motor 8 is decelerated through the pinion 10 and the gear 13 and transmitted to the crankshaft 11, and the crankshaft 11 is driven to rotate at a predetermined speed. The rotation of the crankshaft 11 is converted into a reciprocating linear motion in the front-rear direction in the cylinder 17 of the piston 20 by the crankpin 15 and the connecting rod 22. At this time, when the tip tool 26 is pressed against a work material (not shown), the reaction force is transmitted to the other slide sleeve 31 via the intermediate element 27, the annular member 28, the pin 29 and one slide sleeve 30. The slide sleeve 31 moves backward on the cylinder 17 against the urging force of the spring 36 and closes the breathing hole 25 of the cylinder 17. As a result, the air chamber 24 formed in the cylinder 17 is in a substantially sealed state, and the internal pressure of the air chamber 24 fluctuates due to the reciprocating motion of the piston 20 described above. Is reciprocated in the front-rear direction and intermittently collides with the intermediate element 27, so that the striking force is transmitted from the intermediate element 27 to the tip tool 26.

2) Rotation mode:
The rotation mode is a mode in which only the rotational force is transmitted to the tip tool 26 and rotationally driven. In the state where the switching member 6 is rotated 180 ° from the position shown in FIG. 7 and the rotation mode is selected. The cam 6a and the eccentric pin 6b of the switching member 6 are in the positions shown in FIG.

  Therefore, at this time, as shown in FIG. 4, the connecting member 35 whose outer peripheral step is in contact with the eccentric pin 6b of the switching member 6 is connected to the bevel gear 34 in the same manner as in the rotation / striking mode. The joint claws 35b and 34a (see FIG. 5) are in an engaged state (clutch ON state). Further, the rotation locking member 32 whose rear end surface is in contact with the end surface (cam surface) of the cam 6 a of the switching member 6 is moved forward against the biasing force of the spring 33 by the cam 6 a and is moved to the slide sleeve 31. Since the abutment and the other slide sleeve 30 are moved forward along the outer periphery of the cylinder 17 together with the other slide sleeve 30, the block of the breathing hole 25 by the slide sleeve 31 is released, and the air chamber 24 in the cylinder 17 is in an open state. The air is in communication with the outside air through the breathing hole 25.

  As described above, in the rotation mode, since the connecting member 35 and the bevel gear 34 are in the connected state (clutch ON state), the rotation of the output shaft (motor shaft) 9 of the motor 8 is the same as in the rotation / blow mode. Is transmitted to the cylinder 17 through the path, and the cylinder 17 and the tip tool 26 attached thereto are rotationally driven, and the tip tool 26 functions only as a drill.

  On the other hand, in this rotation mode, the rotation of the output rotation (motor shaft) 9 of the motor 8 is converted into the reciprocating linear motion in the cylinder 17 of the piston 20 as in the rotation / striking mode. In addition, since the breathing hole 25 of the cylinder 17 is in an open state and the air chamber 24 in the cylinder 20 communicates with the outside air, no pressure fluctuation occurs in the air chamber 24 even if the piston 20 reciprocates. Accordingly, transmission of the striking force to the tip tool 26 is interrupted, and the tip tool 26 is only driven to rotate. At this time, the reaction force of the pressing force of the tip tool 26 against the work material is transmitted to the intermediate element 27, the annular member 28, the pin 29, and the slide sleeves 30 and 31, but the slide sleeve 31 is a rotary connecting member. Since the position in the axial direction of the cylinder 17 is restricted, it does not move, and the breathing hole 25 of the cylinder 17 is kept open.

3) Impact mode:
The striking mode is a mode in which only the striking force is transmitted to the tip tool 26. When the striking mode is selected by turning the switching member 6 90 ° clockwise from the position shown in FIG. 8, the switching member is selected. 6 cam 6a and eccentric pin 6b are in the position shown in FIG.

  Therefore, at this time, as shown in FIG. 5, the connecting member 35 whose outer peripheral step is in contact with the eccentric pin 6b of the switching member 6 is moved forward on the cylinder 17 by the eccentric pin 6b, The rotation is separated and connected to the rotation locking member 32 to lock its rotation. That is, the engaging claws 35b, 34a of the connecting member 35 and the bevel gear 34 are in a disengaged state (clutch OFF state), and the engaging claws 35a, 32a of the connecting member 35 and the rotation locking member 32 are in an engaged state (clutch). ON state).

  Further, the rotation locking member 32 whose rear end surface abuts on the end surface (cam surface) of the cam 6a of the switching member 6 moves to the same position as in the rotation / striking mode, and the slide sleeve 31 closes the breathing hole 25 of the cylinder 17. Move to the position you want.

  As described above, in the rotation mode, since the connecting member 35 and the bevel gear 34 are in the disengaged state (clutch OFF state), the bevel gear 34 rotates idly on the cylinder 17 and transmission of the rotation to the cylinder 17 is interrupted. The cylinder 17 and the tip tool 26 attached to the cylinder 17 are in a non-rotating state, and their rotation is locked by the connection of the connecting member 35 and the rotation locking member 32.

  On the other hand, in this rotation mode, since the breathing hole 25 of the cylinder 17 is closed by the slide sleeve 31 as in the rotation / striking mode, the air chamber 24 in the cylinder 17 is kept in a substantially sealed state, and the piston 20 As the reciprocating motion occurs, pressure fluctuations occur in the air chamber 24, and the striking force is transmitted to the tip tool 26 through the striking element 21 and the intermediate element 27 as described above, and the tip tool 26 functions only as a hammer.

4) Neutral:
Neutral is a mode in which neither rotational force nor striking force is transmitted to the tip tool 26, and when the switching member 6 is rotated approximately 45 ° clockwise from the position shown in FIG. The cam 6a and the eccentric pin 6b are in the positions shown in FIG.

  Therefore, at this time, as shown in FIG. 6, the connecting member 35 whose outer peripheral step is in contact with the eccentric pin 6 b of the switching member 6 is moved forward on the cylinder 17 by the eccentric pin 6 b, and is moved from the bevel gear 34. They are separated and are not connected to the bevel gear 34 or the rotation locking member 32.

  Further, the rotation locking member 32 whose rear end surface abuts on the end surface (cam surface) of the cam 6a of the switching member 6 moves forward against the urging force of the spring 33 by the cam 6b, similarly to the rotation mode. In order to contact the slide sleeve 31 and move it forward along the outer periphery of the cylinder 17 together with the other slide sleeve 30, the obstruction of the breathing hole 25 by the slide sleeve 31 is released, and the air chamber in the cylinder 17 is released. 24 is in a state communicating with the outside air.

  As described above, in the neutral state, the connecting member 35, the bevel gear 34, and the rotation locking member 32 are in the disengaged state (clutch OFF state), and the breathing hole 25 of the cylinder 17 is in the open state. Neither the striking force nor the rotational force is transmitted, and the tip tool 26 is in an inoperative state. In this state, since the tip tool 26 can idle, the position in the rotation direction can be easily changed.

  As described above, in the present embodiment, the switching member 6 is operated to open and close the breathing hole 25 of the cylinder 17 by the slide sleeve 31 to switch the striking mode, and the connecting member 35 is engaged with and disengaged from the bevel gear 34. Since the configuration for switching the rotation mode is adopted, the slide sleeve 31 and the connecting member 35 constituting the switching mechanism can be collectively arranged around the cylinder 6, and the structure of the switching mechanism is simplified and the number of component parts is reduced. As a result, the hammer drill 1 can be reduced in size and weight, cost reduction, operability and durability can be improved.

  Here, in the present embodiment, the engagement / disengagement (ON / OFF) of the connecting member 35 with the bevel gear 34 and the cylinder by the slide sleeve 31 when the rotation / blow mode, rotation mode, blow mode, and neutral are selected as the operation mode. Table 1 shows the combinations of opening and closing of 17 breathing holes 25.

＜実施の形態２＞
次に、本発明の実施の形態を図１１及び図１２に基づいて説明する。

<Embodiment 2>
Next, an embodiment of the present invention will be described with reference to FIGS.

  11 is a side sectional view showing a state of the hammer drill according to the present embodiment in the rotation mode, and FIG. 12 is a side sectional view showing a state of the hammer drill in the rotation / striking mode. The same elements as those shown in FIGS. 4 to 6 are denoted by the same reference numerals, and description thereof will be omitted below.

  In the hammer drill 1 ′ according to the present embodiment, the cylinder 17 is held so as to be movable back and forth, and a bevel gear 34 is spline-fitted to the outer peripheral portion of the rear end of the cylinder 17 so that the cylinder 17 is connected to the bevel gear 34. Move back and forth. Accordingly, the cylinder 17 and the tip tool 26 attached to the cylinder 17 via the tool sleeve 37 are always rotated together with the bevel gear 34.

  A slide sleeve 38 and a fixed sleeve 39 are fitted on the outer periphery of the cylinder 17. The slide sleeve 38 is slidably held back and forth on the cylinder 17, and the fixed sleeve 39 is pivoted by a snap ring 40. The direction position is fixed. The slide sleeve 38 is constantly urged forward by a spring 41 that is compressed between the slide sleeve 38 and the fixed sleeve 39.

  Thus, in the hammer drill 1 ′ having the above configuration, the rotation mode and the rotation / striking mode can be selected as the operation mode, and the tip tool 26 is always driven to rotate.

  The operation of the hammer drill 1 'according to the present embodiment will be described below in 1) rotation mode and 2) rotation / striking mode.

1) Rotation mode:
When the rotation mode is selected by the rotation operation of the switching member 6, the cam 6a of the switching member 6 contacts the slide sleeve 38 and moves it forward as shown in FIG. Then, the cylinder 17 to which the pin 29 that engages with the slide sleeve 38 is inserted and fixed also moves forward together with the slide sleeve 38, and the breathing hole 25 formed in the cylinder 17 is positioned forward of the fixed sleeve 38 and opened. Therefore, the air chamber 24 in the cylinder 17 communicates with the outside air through the breathing hole 25.

  Thus, when the motor 8 is driven, the rotation of the output shaft (motor shaft) 9 is decelerated via the pinion 10, the gear 14, the intermediate shaft 12, and the bevel gears 16 and 34 and transmitted to the cylinder 17. The cylinder 17 and the tip tool 26 attached to the tip of the cylinder 17 are rotationally driven, and the tip tool 26 functions as a drill.

  At the same time, the rotation of the output shaft (motor shaft) 9 of the motor 8 is decelerated through the pinion 10 and the gear 13 and transmitted to the crankshaft 11, and the rotation of the crankshaft 11 is transmitted to the piston 20 by the crankpin 15 and the connecting rod 22. Although it is converted into a reciprocating linear motion in the cylinder 17, as described above, the breathing hole 25 of the cylinder 17 is in an open state, and the air chamber 24 in the cylinder 17 communicates with the outside air. Even if it moves, the pressure fluctuation does not occur in the air chamber 24. Therefore, the transmission of the striking force to the tip tool 26 is cut off, and the tip tool 26 is rotated and functions only as a drill.

2) Rotation / blow mode:
When the rotation / striking mode is selected by the rotation operation of the switching member 6, the slide sleeve 38 and the cylinder 17 that are in contact with the cam 6a of the switching member 6 move backward as shown in FIG. The breathing hole 25 formed in the above is closed by the fixing sleeve 39.

  Accordingly, in this rotation / blow mode, the rotation of the output shaft (motor shaft) 9 of the motor 8 is transmitted to the cylinder 17 through the path, as in the rotation mode. The tip tool 26 mounted on the section is rotationally driven, and the tip tool 26 functions as a drill.

  In this rotation / striking mode, the breathing hole 25 formed in the cylinder 17 is closed by the fixed sleeve 39 as described above, so that the air chamber 24 in the cylinder 17 is kept in a substantially sealed state, and the piston 20 A pressure fluctuation occurs in the air chamber 24 with the reciprocating motion. Due to this pressure fluctuation, the striking element 21 reciprocates back and forth in the cylinder 17 and intermittently collides with the intermediate element 27. Therefore, the striking force is transmitted from the intermediate element 27 to the tip tool 26, and the tip tool 26 serves as a hammer. Also works.

  Thus, in the present embodiment, since the switching member 6 is operated to move the cylinder 17 via the slide sleeve 38 to open and close the breathing hole 25, the operation mode (blow mode) is switched. The slide sleeve 38 and the fixed sleeve 39 constituting the switching mechanism can be collectively arranged around the cylinder 17, and the structure of the switching mechanism is simplified and the number of components is reduced as in the first embodiment. This reduces the size and weight of the hammer drill 1 ', reduces costs, improves operability and durability.

  The present invention is useful for a hammer drill having a switching mechanism for switching operation modes.

It is a side view of the hammer drill concerning the present invention. It is a sectional side view which shows the state at the time of rotation and impact mode of the hammer drill which concerns on Embodiment 1 of this invention. (A) is a side view of a switching member, (b) is a bottom view of the switching member. It is a sectional side view which shows the state at the time of the rotation mode of the hammer drill which concerns on Embodiment 1 of this invention. It is a sectional side view which shows the state at the time of the hammering mode of the hammer drill which concerns on Embodiment 1 of this invention. It is a sectional side view which shows the state at the time of neutral of the hammer drill which concerns on Embodiment 1 of this invention. It is a figure which shows the position of the cam of a switching member and the eccentric pin at the time of rotation and impact mode of the hammer drill which concerns on Embodiment 1 of this invention. It is a figure which shows the position of the cam of the switching member at the time of rotation mode of the hammer drill which concerns on Embodiment 1 of this invention, and an eccentric pin. It is a figure which shows the position of the cam of a switching member and the eccentric pin at the time of the hammering mode which concerns on Embodiment 1 of this invention. It is a figure which shows the position of the cam of the switching member and the eccentric pin at the time of the neutral of the hammer drill which concerns on Embodiment 1 of this invention. It is a sectional side view which shows the state at the time of the rotation mode of the hammer drill which concerns on Embodiment 2 of this invention. It is a sectional side view which shows the state at the time of rotation and impact mode of the hammer drill which concerns on Embodiment 2 of this invention.

Explanation of symbols

1, 1 'hammer drill 6 switching member 6a cam 6b eccentric pin 8 motor 9 output shaft (motor shaft)
DESCRIPTION OF SYMBOLS 10 Pinion 11 Crankshaft 12 Intermediate shaft 13,14 Gear 15 Crankpin 16 Bevel gear 17 Cylinder 20 Piston 21 Strike element 22 Connecting rod 24 Air chamber 25 Breathing hole 26 Tip tool 27 Meson 28 Ring member 29 Pin 30, 31 Slide sleeve 32 Rotation Locking member 33 Spring 34 Bevel gear 35 Connecting member 36 Spring 38 Slide sleeve 39 Fixed sleeve 41 Spring

Claims (9)

A striking element is slidably fitted in the cylinder, the rotation of the motor as a driving source is converted into a reciprocating motion of the piston in the cylinder, and the piston and the striking element are defined in the cylinder. A striking mechanism for transmitting a striking force to the tip tool via the striking element by pressure fluctuations in the air chamber;
A rotation transmission mechanism that transmits the rotation of the motor to the cylinder via a gear and rotationally drives the cylinder and the tip tool engaged therewith;
In a hammer drill comprising
A first mode in which an intake hole for communicating the air chamber and the outside air is formed in the cylinder, and the breathing hole can be closed according to the movement of the tip tool toward the striker; A hammer drill provided with a switching mechanism that enables switching to the second mode to be opened.   The hammer drill according to claim 1, wherein the switching mechanism is capable of switching the mode by regulating an amount of movement of the tip tool toward the striker.   The switching mechanism has a sleeve that is movably fitted to the cylinder and that can open and close the breathing hole in conjunction with movement of the tip tool toward the striker, and restricts movement of the sleeve. The hammer drill according to claim 1, wherein the mode can be switched by doing so.   The cylinder can be moved according to the movement of the tip tool toward the striker side, and the switching mechanism can switch the mode by restricting the movement amount of the cylinder. The hammer drill according to claim 1.   The hammer drill according to any one of claims 1 to 4, wherein the switching mechanism includes a rotatable cam, and the mode can be switched depending on a rotation position of the cam.   The hammer drill according to any one of claims 1 to 5, wherein the switching mechanism can also be switched to a third mode in which rotational driving of the cylinder is released.   The hammer drill according to any one of claims 1 to 6, wherein an operation mode of the tip tool can be switched between a rotation / striking mode, a rotation mode, and a striking mode by the switching mechanism.   The rotation transmission mechanism is provided with a connecting member that is rotatably provided on the outer periphery of the cylinder and that is slidably fitted on the outer periphery of the cylinder, and the connecting member is operated by operating the switching member of the switching mechanism. The hammer drill according to claim 1, wherein the gear is engaged with and disengaged from the gear.   9. The switch member according to claim 8, wherein the switch member is provided with an eccentric pin, and the connecting member is moved by the eccentric pin by a rotation operation of the switch member and is engaged with and disengaged from the gear. Hammer drill.

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