Work machine

Abstract

To improve workability of a work machine.SOLUTION: A housing 20 includes: a resin-made motor case 30 which extends in an axial direction of an output shaft 33a and supports an electric motor 31 therein; metal-made first and second support cases 40, 50 which have a first support surface 41a for supporting one side in an axial direction of the motor case 30 and a cylindrical mounting section 51a1 for supporting the other side in the axial direction of the motor case 30 and supports a gear mechanism 43, a crankshaft 44 and a striking unit 53 therein. Thus, the electric motor 31 can be supported by only the resin-made motor case 30 and both sides in the axial direction of the motor case 30 can be supported by the first and second support cases 40, 50 having high rigidity. Therefore, workability of an electric hammer 10 can be improved.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a work machine having an operating unit operated by a motor. [Background technology]

[0002] Patent Document 1 describes an example of an electric tool equipped with multiple gears and pistons operated by a motor. The electric tool described in Patent Document 1 has a cylinder housing that houses a striker, a hammer member, etc., a gear housing that houses multiple gears, and a motor housing that houses a motor.

[0003] The cylinder housing, gear housing and motor housing are assembled together, and the motor housing is made of an aluminum alloy to improve the cooling performance of the motor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-120208 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above-mentioned Patent Document 1, the stator forming the motor is covered with a resin motor case, and further, an aluminum alloy motor housing is provided radially outwardly of the resin motor case via a cooling passage, which increases the weight and size of the power tool, resulting in a problem of reduced workability.

[0006] An object of the present invention is to improve the workability of a work machine. [Means for solving the problem]

[0007] In one embodiment of the present invention, a motor having an output shaft, an operating unit that operates upon rotation of the output shaft, and a housing that accommodates the motor and the operating unit, the housing including a resin motor case that extends in the axial direction of the output shaft and supports the motor internally, and a metal support case that has a first support portion that supports one axial side of the motor case and a second support portion that supports the other axial side of the motor case, and that supports the operating unit internally. Effect of the Invention

[0008] According to the present invention, the workability of a work machine can be improved. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a perspective view of the electric hammer as seen from the left side. [Diagram 2] 2 is a cross-sectional view taken along the front-rear direction of the electric hammer of FIG. 1. [Diagram 3] FIG. 3 is an enlarged cross-sectional view of the periphery of the handle in FIG. 2. [Figure 4] FIG. 3 is an enlarged cross-sectional view of the piston and its periphery in FIG. 2. [Diagram 5] FIG. 2 is a perspective view showing the back cover and the handle. [Figure 6] FIG. [Figure 7] FIG. 4 is a perspective view showing a first support case. [Figure 8] FIG. 4 is a perspective view showing a second support case. [Figure 9] FIG. 1 is a diagram illustrating an assembly procedure (1) for an electric hammer. [Figure 10] FIG. 13 is a diagram illustrating the assembly procedure (2) of the electric hammer. [Figure 11] FIG. 11 is a diagram illustrating the assembly procedure (3) of the electric hammer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0011] Figure 1 is an oblique view of the electric hammer from the left side, Figure 2 is a cross-sectional view along the front-to-back direction of the electric hammer in Figure 1, Figure 3 is an enlarged cross-sectional view of the handle area in Figure 2, Figure 4 is an enlarged cross-sectional view of the piston area in Figure 2, Figure 5 is an oblique view showing the back cover and handle, Figure 6 is an oblique view showing the motor case, Figure 7 is an oblique view showing the first support case, and Figure 8 is an oblique view showing the second support case.

[0012] <Electric hammer> As shown in Fig. 1 and Fig. 2, a tool 11 (see imaginary lines) is detachably attached to the electric hammer 10. By operating the electric hammer 10, the tool 11 repeats striking motions at a predetermined frequency. For example, the tool 11 has a so-called "bull point" formed in a tapered rod shape. This allows the electric hammer 10 to be used to perform drilling, chipping, and crushing operations on objects such as concrete and stone.

[0013] The electric hammer 10 corresponds to the working machine in the present invention.

[0014] 1 and 2, the axial direction of the output shaft 33a included in the electric motor 31 is defined as the "up-down direction." The moving direction of the tool 11 struck by the striking unit 53 is defined as the "front-rear direction." Furthermore, the direction perpendicular to both the axial direction of the output shaft 33a (up-down direction) and the moving direction of the tool 11 (front-rear direction) is defined as the "left-right direction."

[0015] <Housing> The electric hammer 10 has a housing 20 that forms its outer shell. The electric motor 31, gear mechanism 43, crankshaft 44, and striking unit 53 are housed inside the housing 20. The housing 20 includes a motor case 30, a first support case 40, a second support case 50, a back cover 60, and a handle 70. The motor case 30, the first support case 40, the second support case 50, the back cover 60, and the handle 70 are fixed to one another by a screw member S1 (see Figures 10 and 11).

[0016] <Electric motor> 2 and 3, the motor case 30 is formed into a generally cylindrical shape by injection molding a resin material such as plastic. The motor case 30 extends in the vertical direction of the electric hammer 10, and an electric motor 31 is provided radially inside the motor case 30.

[0017] Specifically, the motor case 30 extends in the axial direction of the output shaft 33a that forms the electric motor 31, and supports the electric motor 31 therein. The electric motor 31 has a stator 32 and a rotor 33, and corresponds to the motor in the present invention.

[0018] The stator 32 is formed in a generally cylindrical shape, and the radial outer side of the stator 32 is fixed to the inner wall of the motor case 30. The stator 32 includes a stator core 32a made of a ferromagnetic material and a stator coil 32b wound around the stator core 32a. A driving current is supplied to the stator coil 32b via an electric wire EL. This causes the stator core 32a to generate an electromagnetic force.

[0019] Further, a rotor 33 is rotatably provided radially inside the stator 32. An output shaft 33a is provided at the center of rotation of the rotor 33. The output shaft 33a extends in the vertical direction of the electric hammer 10, and operates a gear mechanism 43 disposed on the upper side of the electric hammer 10. That is, the rotational force of the output shaft 33a is transmitted to the gear mechanism 43.

[0020] A rotor core 33b is fixed to the approximate center of the output shaft 33a in the axial direction, and a rotor coil 33c is wound around the rotor core 33b. A commutator 33d is fixed to the other axial side (lower side) of the output shaft 33a, and an end of the rotor coil 33c is electrically connected to the commutator 33d.

[0021] A pair of carbon brushes (not shown) are in sliding contact with the commutator 33d. Thus, by supplying a drive current to the carbon brushes, the rotor 33 rotates at a predetermined rotation speed in a predetermined rotation direction relative to the stator 32. Here, the pair of carbon brushes can be easily replaced by attaching and detaching brush caps BC (only the left one is shown in FIG. 1) provided on the left and right sides of the electric hammer 10, as shown in FIG. 1. This allows for easy maintenance.

[0022] 3, one axial side (upper side) of the output shaft 33a is rotatably supported by a first ball bearing B1. On the other hand, the other axial side (lower side) of the output shaft 33a is rotatably supported by a second ball bearing B2. Here, the first ball bearing B1 is mounted on a first case body 41 forming a first metallic support case 40, and the second ball bearing B2 is mounted on a second case body 51 forming a second metallic support case 50.

[0023] In this manner, the stator 32 of the electric motor 31 is supported by the resin motor case 30, and the output shaft 33a of the rotor 33 is rotatably supported by the metal first case body 41 and second case body 51. This allows the motor case 30 to be lightweight while still allowing the output shaft 33a to be stably rotated.

[0024] <Gear mechanism> 3, the first support case 40 includes a first case body 41 and a cover member 42. The first case body 41 and the cover member 42 are both made of metal, and the small diameter gear G1 and the large diameter gear G2 are rotatably housed therein. That is, the first support case 40 is made of metal, and supports the gear mechanism 43 consisting of the small diameter gear G1 and the large diameter gear G2 without rattling.

[0025] The gear mechanism 43 corresponds to the operating portion and the first operating portion in this invention.

[0026] The small diameter gear G1 is meshed with a pinion gear PG that is integrally provided on one side of the output shaft 33a in the axial direction, and rotates with the rotation of the pinion gear PG. The number of teeth of the pinion gear PG is smaller than the number of teeth of the small diameter gear G1. As a result, the small diameter gear G1 rotates at a slower speed and with a higher torque than the pinion gear PG.

[0027] One axial side (upper side) of the small diameter gear G1 is rotatably supported by a third ball bearing B3 attached to the cover member 42. On the other hand, the other axial side (lower side) of the small diameter gear G1 is rotatably supported by a fourth ball bearing B4 attached to the first case body 41.

[0028] The large diameter gear G2 forming the gear mechanism 43 is meshed with the small diameter gear G1 and rotates with the rotation of the small diameter gear G1. The large diameter gear G2 has a larger diameter than the small diameter gear G1, and the number of teeth of the small diameter gear G1 is smaller than the number of teeth of the large diameter gear G2. As a result, the large diameter gear G2 rotates at a slower speed and with a higher torque than the small diameter gear G1. In this way, the gear mechanism 43 is actuated by the rotation of the output shaft 33a, and forms a reduction mechanism that decelerates the rotation of the output shaft 33a to increase the torque.

[0029] Here, the small diameter gear G1 and the large diameter gear G2 forming the gear mechanism 43 are aligned horizontally with respect to the pinion gear PG forming the electric motor 31. Specifically, the small diameter gear G1 and the large diameter gear G2 are arranged to be aligned in front of the pinion gear PG. In other words, the gear mechanism 43 is supported by the first support case 40 so as to overlap with the electric motor 31 in a direction (front-rear direction) intersecting with the axial direction (up-down direction) of the output shaft 33a. This prevents the electric hammer 10 from becoming large in the up-down direction (axial direction of the output shaft 33a).

[0030] The crankshaft 44 is fixed to the center of rotation of the large diameter gear G2 by press fitting or the like, and rotates with the rotation of the large diameter gear G2. One axial side (upper side) of the crankshaft 44 is rotatably supported by a fifth ball bearing B5 attached to the cover member 42. Meanwhile, the axial center portion of the crankshaft 44 is rotatably supported by a sixth ball bearing B6 attached to the first case body 41.

[0031] The fifth and sixth ball bearings B5 and B6 are larger than the third and fourth ball bearings B3 and B4 in order to receive a relatively large radial load acting on the crankshaft 44 when the electric hammer 10 is in operation.

[0032] A crank pin 44a is integrally provided on the other axial side (lower side) of the crankshaft 44. The crank pin 44a extends in the vertical direction of the electric hammer 10, similar to the crankshaft 44, and the crankshaft 44, the crank pin 44a, and the output shaft 33a of the electric motor 31 are parallel to one another.

[0033] Specifically, the crankshaft 44 overlaps with the output shaft 33a when the electric hammer 10 is viewed from the front-rear direction. The crank pin 44a protrudes to the other axial side relative to the crankshaft 44. This prevents the electric hammer 10 from becoming large in the vertical direction (axial direction of the output shaft 33a).

[0034] 3, the axis C4 of the crank pin 44a is offset (eccentric) by a predetermined amount with respect to the rotation center C3 of the crankshaft 44. Therefore, the crank pin 44a rotates about the rotation center C3 as the crankshaft 44 rotates.

[0035] The longitudinal base end (rear side) of the connecting rod 54 is rotatably attached to the crank pin 44a via a needle roller bearing B7. The crank pin 44a is provided with an internal thread portion 44b along its axial direction, and a setscrew S2 is screwed into the internal thread portion 44b to prevent the longitudinal base end of the connecting rod 54 from falling off the crank pin 44a.

[0036] Here, the crankshaft 44 is actuated by the rotation of the output shaft 33a via the gear mechanism 43. The crankshaft 44 extends in the axial direction of the output shaft 33a, and connects the gear mechanism 43 and the striking unit 53 so as to be capable of transmitting power. In other words, the gear mechanism 43 is connected to the striking unit 53 by the crankshaft 44 so as to be capable of transmitting power.

[0037] The crankshaft 44 corresponds to the operating portion and the connecting member in the present invention.

[0038] In this way, the rotational force of the output shaft 33a forming the electric motor 31 is transmitted to the crankshaft 44 via the gear mechanism 43. Specifically, as shown in Fig. 3, when the output shaft 33a rotates in the direction of arrow R1 around the rotation center C1, the small diameter gear G1 of the gear mechanism 43 rotates in the direction of arrow R2 around the rotation center C2. In addition, with the rotation of the small diameter gear G1, the large diameter gear G2 and the crankshaft 44 rotate in the direction of arrow R3 around the rotation center C3.

[0039] As a result, the crank pin 44a is also rotated about the rotation center C3. Therefore, the connecting rod 54 (piston 55) housed inside the striking unit case 52 forming the second support case 50 reciprocates in the front-rear direction of the electric hammer 10, as shown by the arrow VB in Figures 3 and 4. In this way, the crankshaft 44 has the function of converting the rotational motion of the electric motor 31 into the linear motion of the piston 55.

[0040] <Strike unit> 2 and 4, the second support case 50 includes a second case body 51 and a striking unit case 52. Both the second case body 51 and the striking unit case 52 are made of metal, and the rear side of the second case body 51 supports the axial lower side of the motor case 30. In addition, the other axial side (the crank pin 44a side) of the crankshaft 44 is housed inside and on the front side of the second case body 51.

[0041] The striking unit 53 is housed inside the striking unit case 52. That is, the striking unit 53 is supported by the striking unit case 52. The striking unit 53 is movable in the front-rear direction of the electric hammer 10 as the crankshaft 44 rotates. The striking unit 53 has a connecting rod 54, a piston 55, a striker (striker) 56, and a hammer member 57.

[0042] The striking unit 53 is actuated by the rotation of the output shaft 33a via the crankshaft 44 and the gear mechanism 43, and corresponds to the actuating portion and the second actuating portion of the present invention.

[0043] 2, the impact unit 53 is supported by the second support case 50 so as to overlap with the electric motor 31 in a direction (front-rear direction) intersecting with the axial direction (up-down direction) of the output shaft 33a. This also prevents the electric hammer 10 from becoming large in the up-down direction (axial direction of the output shaft 33a).

[0044] The striker 56 is disposed in the longitudinal center of the striking unit case 52, and includes a cylindrical portion 56a and a bottom portion 56b. Specifically, the bottom portion 56b closes the axial front side of the cylindrical portion 56a. An opening 56c is provided on the axial rear side of the cylindrical portion 56a, and the longitudinal tip side (front side) of the connecting rod 54 enters and exits the cylindrical portion 56a through the opening 56c.

[0045] A piston 55 is provided via a piston pin 54a so as to be able to swing freely on the longitudinal tip side of the connecting rod 54. The piston 55 is disposed inside a cylindrical portion 56a forming a striker 56, and is movable in the front-rear direction of the electric hammer 10 relative to the striker 56.

[0046] An air damper chamber 58 is formed between the bottom 56b of the striker 56 and the piston 55. The air damper chamber 58 contains air, and has the function of mitigating the reaction force applied to the piston 55 when the electric hammer 10 strikes, thereby reducing (damping) the vibration transmitted to the operator. A pair of annular seals 55a is attached to the outer periphery of the piston 55. Therefore, the air inside the air damper chamber 58 does not leak out to the outside of the striker 56.

[0047] The bottom 56b of the striker 56 is thicker than other parts of the striker 56, ensuring sufficient rigidity. The bottom 56b strikes the hammer member 57 as the piston 55 moves forward. The hammer member 57 is supported by an annular hammer guide 59 attached to the longitudinal front side of the striking unit case 52 so as to be movable in the front-rear direction of the electric hammer 10.

[0048] A tool holder HD that holds the longitudinal base end side (rear side) of the tool 11 is attached to the longitudinal front side of the striking unit case 52. The tip side (front side) of the hammer member 57 struck by the striker 56 can enter the longitudinal base end side (rear side) inside the tool holder HD. As a result, the hammer member 57 strikes the tool 11, and the striking force transmitted to the tool 11 is applied to an object such as concrete or stone.

[0049] An annular stopper member ST is provided inside the tool holder HD and in the center in the longitudinal direction. This stopper member ST restricts the forward movement amount of the hammer member 57 struck by the striker 56. In other words, the hammer member 57 is movable in the front-rear direction of the electric hammer 10 by the distance between the hammer guide 59 and the stopper member ST.

[0050] A side handle SH to be held by an operator is attached to a portion of the striking unit case 52 toward the rear in the longitudinal direction. For example, when performing work using the electric hammer 10, the operator holds the handle 70 with his right hand and holds the side handle SH with his left hand. This allows the operator to hold the electric hammer 10 in a well-balanced manner with both hands, improving workability.

[0051] <Back cover> 1, 3 and 5, the back cover 60 extends in the up-down direction of the electric hammer 10. The back cover 60 is formed in a substantially U-shape by injection molding a resin material such as plastic. The back cover 60 includes a motor case covering portion 61 that covers the rear of the motor case 30, a first support case covering portion 62 that covers the rear of the first support case 40, and a second support case covering portion 63 that covers the rear of the second support case 50.

[0052] Here, the back cover 60 partially covers the motor case 30, the first support case 40, and the second support case 50, improving the appearance of the electric hammer 10. The back cover 60 is thinner than the motor case 30, and prevents the weight of the electric hammer 10 from increasing. Note that by preparing back covers 60 in different colors, the variety of electric hammers 10 can be increased.

[0053] <Handle> 1, 3 and 5, a handle 70 to be held by an operator is provided at the rear of the electric hammer 10. The handle 70 is formed into a substantially U-shape by injection molding a resin material such as plastic. The handle 70 extends in the vertical direction of the electric hammer 10 and is hollow.

[0054] Furthermore, the handle 70 is disposed so as to overlap the electric motor 31 in a direction (front-rear direction) intersecting with the axial direction (up-down direction) of the output shaft 33a. This allows the relatively heavy electric motor 31 to be disposed in front of the handle 70 (toward the target object such as concrete or stone), optimizing the weight balance of the electric hammer 10 with respect to the working posture of the worker. This improves workability.

[0055] The handle 70 comprises a handle main body 71 which is gripped by the operator, an upper connecting portion 72 which faces the first support case covering portion 62 in the fore-and-aft direction of the electric hammer 10, and a lower connecting portion 73 which faces the second support case covering portion 63 in the fore-and-aft direction of the electric hammer 10.

[0056] A limit switch 74 for operating the electric motor 31 is provided inside the handle body 71. The limit switch 74 is turned on and off by a trigger switch 75 operated by an operator. A power cord PC is electrically connected to the limit switch 74. As a result, a drive current is supplied to the electric motor 31 by turning on the limit switch 74.

[0057] The upper connecting part 72 is connected to the first support case 40 so as to be movable relative to the front-rear direction of the electric hammer 10. In other words, the upper connecting part 72 arranged on one side (upper side) in the longitudinal direction of the handle 70 is movable relative to the first support case 40 in a direction (front-rear direction) intersecting the axial direction (up-down direction) of the output shaft 33a.

[0058] A vibration reduction mechanism 76 is provided between the upper connecting portion 72 and the first support case 40. The vibration reduction mechanism 76 has a function of suppressing (attenuating) the transmission of vibrations caused by the forward and backward movement of the striking unit 53 (see FIG. 4) to the handle 70. Specifically, the vibration reduction mechanism 76 includes a damper member 76a and a spring 76b (see FIG. 3). This makes it possible to protect the operator from vibrations, improving workability.

[0059] Further, the lower connecting part 73 is rotatably connected to the second support case 50. Specifically, the lower connecting part 73 arranged on the other axial side (lower side) of the handle 70 is rotatable about a rotation axis PS attached to the second case body 51 forming the second support case 50. By rotatably connecting the lower connecting part 73 to the second support case 50 in this manner, the vibration reduction mechanism 76 provided between the upper connecting part 72 and the first support case 40 can be operated smoothly.

[0060] Here, the handle body 71 forming the handle 70 is formed in a rod shape extending in the axial direction (up and down direction) of the output shaft 33a, and an upper connecting portion 72 on one longitudinal side (upper side) of the handle 70 is supported by the first support case 40 via a vibration reduction mechanism 76, and a lower connecting portion 73 on the other longitudinal side (lower side) of the handle 70 is supported by the second support case 50.

[0061] This allows the trigger switch 75 to be disposed between the handle 70 and the electric motor 31, and also allows the operator's fingers to be placed in the space between the handle 70 and the electric motor 31. This makes it easier to hold the electric hammer 10, and makes it easier to transport the electric hammer 10.

[0062] <Motor case details> 6, the resin motor case 30 includes a cylindrical main body 30a that supports an electric motor 31 (see FIG. 3) therein. A stator 32 (see FIG. 3) that forms the electric motor 31 is fixed to the radially inner side of the cylindrical main body 30a.

[0063] A fitting cylindrical portion 30b is provided on the axial lower side of the motor case 30, which is fitted into the inside of a cylindrical mounting portion 51a1 (see FIG. 8) provided on the second case body 51. That is, the motor case 30 has a cylindrical main body 30a and a fitting cylindrical portion 30b, with the cylindrical main body 30a disposed on one axial side (upper side) of the motor case 30 and the fitting cylindrical portion 30b disposed on the other axial side (lower side) of the motor case 30.

[0064] A flat abutment portion 30a1 that abuts against a flat wall portion 51b3 (see FIG. 8) provided on the second case body 51 is provided on the radially outer side of the cylindrical body 30a. Specifically, the flat abutment portion 30a1 is disposed on the front side of the motor case 30. This prevents the motor case 30 from rattling relative to the second case body 51 (see FIG. 8) when the electric hammer 10 is assembled.

[0065] A pair of exposed portions 30a2 are provided on the radially outer side of the cylindrical body 30a, and these exposed portions 30a2 are disposed on the left and right sides of the motor case 30, respectively (only one is shown in FIG. 6). When the electric hammer 10 is in an assembled state, the pair of exposed portions 30a2 are exposed to the outside without being covered by anything, as shown in FIG.

[0066] In this way, the motor case 30 exposes to the outside a pair of exposed parts 30a2 that form at least a part of the outer circumferential surface of the motor case 30. As a result, by preparing motor cases 30 of different colors, it is possible to increase the variety of the electric hammer 10 while improving the design of the electric hammer 10.

[0067] Furthermore, an arc-shaped wall portion 30a3 is provided on the radially outer side of the cylindrical body 30a. Specifically, the arc-shaped wall portion 30a3 is disposed on the rear side of the motor case 30. The arc-shaped wall portion 30a3 is covered by a motor case covering portion 61 (see FIG. 5) of the back cover 60 when the electric hammer 10 is in an assembled state.

[0068] Moreover, an opening 30a4 is provided on one axial side (upper side) of the cylindrical body 30a, which serves as an insertion port for a stator 32 that forms the electric motor 31. The opening 30a4 connects the inside and outside of the motor case 30, and corresponds to a first opening in the present invention.

[0069] Furthermore, an abutment surface portion 30a5 is provided on one axial side of the cylindrical main body 30a so as to surround the opening 30a4. This abutment surface portion 30a5 abuts against a first case main body 41 that forms the first support case 40. Specifically, the abutment surface portion 30a5 abuts against a first support surface 41a (see FIGS. 3 and 7) provided on the first case main body 41, and is supported by the first support surface 41a.

[0070] In this manner, the first case body 41 forming the first support case 40 covers the opening 30a4 of the motor case 30. This effectively prevents dust and other foreign matter from entering the interior of the motor case 30.

[0071] The fitting cylinder portion 30b is provided with a side wall portion 30b1, and the side wall portion 30b1 is provided with a pair of brush holder insertion holes 30b2 through which a brush holder (not shown) is inserted (only one of the holes is shown in FIG. 6). The pair of brush holder insertion holes 30b2 are provided at intervals of 180 degrees in the circumferential direction of the fitting cylinder portion 30b, and are disposed on the left and right sides of the motor case 30, respectively.

[0072] Furthermore, a bottom wall portion 30b3 is provided on the other axial side (lower side) of the fitting cylinder portion 30b. That is, the lower side of the fitting cylinder portion 30b is closed by the bottom wall portion 30b3. The bottom wall portion 30b3 is provided with a plurality of ventilation holes H that communicate the inside and outside of the fitting cylinder portion 30b, and cooling air flows through these ventilation holes H when the electric motor 31 is operating. Therefore, the electric motor 31 can be protected from overheating.

[0073] The multiple air holes H communicate with the inside and outside of the motor case 30 and correspond to the second openings in the present invention. When the electric hammer 10 is in an assembled state, the multiple air holes H are covered by a closed bottom portion 51a2 (see FIG. 3) of the second case body 51 that forms the second support case 50. This effectively prevents dust and the like from entering the inside of the motor case 30.

[0074] 3, a cooling fan FN is integrally provided on the output shaft 33a of the electric motor 31. As a result, cooling air flows through each of the ventilation holes H when the electric motor 31 is operating.

[0075] <Details of the first support case> As shown in Figs. 3 and 7, the metal first support case 40 is formed by assembling a first case body 41 and a cover member 42, and supports a gear mechanism 43 therein.

[0076] The first case body 41 is formed in a generally plate-like shape, and has a first support surface 41a on the side (lower side) where the motor case 30 and the second support case 50 are provided. In contrast, a second support surface 41b is provided on the side (upper side) where the cover member 42 is provided.

[0077] When the electric hammer 10 is assembled, the abutting surface 30a5 (see FIG. 6) of the motor case 30 and the fixing surface 51b6 (see FIG. 8) of the second case body 51 abut against the first support surface 41a. That is, the first support surface 41a of the first case body 41 supports the motor case 30 and the second case body 51, respectively.

[0078] The first support surface 41a supports the abutment surface portion 30a5 on one axial side (upper side) of the motor case 30 and corresponds to the first support portion in the present invention. The first support case 40 having the first support surface 41a corresponds to the support case in the present invention.

[0079] Meanwhile, an abutting portion 42a provided on the first case body 41 side (lower side) of the cover member 42 abuts against the second support surface 41b. As a result, the gear mechanism 43 is rotatably housed in the space formed between the first case body 41 and the cover member 42.

[0080] The first case body 41 is provided with a first bearing mounting portion 41c, a second bearing mounting portion 41d, and a third bearing mounting portion 41e. The first, second, and third bearing mounting portions 41c, 41d, and 41e are provided so as to penetrate the first case body 41 in the up-down direction. The first, second, and third bearing mounting portions 41c, 41d, and 41e are arranged in this order from the rear side to the front side in the front-rear direction of the first case body 41.

[0081] Here, a first ball bearing B1 that rotatably supports one axial side of the output shaft 33a is mounted on the first bearing mounting portion 41c. A fourth ball bearing B4 that rotatably supports the other axial side of the small-diameter gear G1 is mounted on the second bearing mounting portion 41d. Furthermore, a sixth ball bearing B6 that rotatably supports the axial center portion of the crankshaft 44 is mounted on the third bearing mounting portion 41e.

[0082] The cover member 42 is formed in a substantially dish shape, and an abutment portion 42a that abuts against the second support surface 41b of the first case body 41 is provided on the first case body 41 side (lower side) of the cover member 42.

[0083] Furthermore, a fourth bearing mounting portion 42b and a fifth bearing mounting portion 42c are provided on the inside of the cover member 42. These fourth and fifth bearing mounting portions 42b, 42c are recessed into the upper side of the cover member 42.

[0084] A third ball bearing B3 that rotatably supports one axial side of the small-diameter gear G1 is mounted on the fourth bearing mounting portion 42b, and a fifth ball bearing B5 that rotatably supports one axial side of the crankshaft 44 is mounted on the fifth bearing mounting portion 42c.

[0085] 7, a generally L-shaped recessed portion 42d is provided at the rear of the cover member 42. Specifically, the recessed portion 42d includes side walls 42e extending in the up-down and left-right directions and a bottom wall 42f extending in the front-rear and left-right directions.

[0086] The side wall 42e is provided with a support protrusion 42g that protrudes rearward by a predetermined height, and the support protrusion 42g supports the front of the vibration reduction mechanism 76 (see FIG. 3). The bottom wall 42f also supports the front of the vibration reduction mechanism 76 in the up-down direction of the cover member 42 (see FIG. 3).

[0087] <Details of the second support case> 3, 4 and 8, the metal second support case 50 is formed by assembling a second case body 51 and a striking unit case 52, and supports therein a striking unit 53. The striking unit case 52 is formed in a simple, generally cylindrical shape, as shown in FIG.

[0088] The second case body 51 includes a motor support portion 51a formed in a substantially cylindrical shape and a crank accommodating portion 51b formed in a substantially rectangular parallelepiped shape. As shown in Fig. 8, the motor support portion 51a and the crank accommodating portion 51b are connected to each other in a stepped manner. Specifically, the motor support portion 51a is disposed on the rear and lower side of the second case body 51, and the crank accommodating portion 51b is disposed on the front and upper side of the second case body 51.

[0089] The motor support part 51a includes a cylindrical mounting part 51a1 and a closed bottom part 51a2 that closes the other axial side (lower side) of the cylindrical mounting part 51a1. The fitting cylindrical part 30b (see FIG. 6) of the motor case 30 is fitted into the inside of the cylindrical mounting part 51a1. This prevents the motor case 30 from rattling with respect to the motor support part 51a.

[0090] The cylindrical mounting portion 51a1 supports the fitting cylindrical portion 30b on the other axial side (lower side) of the motor case 30, and corresponds to the second support portion in the present invention. The second support case 50 having the cylindrical mounting portion 51a1 corresponds to the support case in the present invention.

[0091] Here, a sixth bearing mounting portion 51a3 is integrally provided on the closed bottom portion 51a2 as shown in Fig. 3. The sixth bearing mounting portion 51a3 is provided penetrating the motor support portion 51a in the up-down direction, and a second ball bearing B2 that rotatably supports the other axial end of the output shaft 33a is mounted on the sixth bearing mounting portion 51a3.

[0092] A shaft support portion 51a4 is integrally provided on the radially outer side and rear side of the motor support portion 51a. Specifically, the shaft support portion 51a4 protrudes toward the rear of the motor support portion 51a at a predetermined height and is provided with a shaft mounting hole 51a5 that penetrates in the left-right direction. A rotating shaft PS that rotatably supports the handle 70 is mounted in the shaft mounting hole 51a5.

[0093] Further, a pair of brush holder fixing holes 51a6 to which a brush holder (not shown) is fixed are provided on the left and right sides of the motor support portion 51a. These brush holder fixing holes 51a6 face a pair of brush holder insertion holes 30b2 (see FIG. 6) provided in the motor case 30 in the left-right direction of the electric hammer 10, respectively.

[0094] As shown in Fig. 8, the crank accommodating portion 51b is provided integrally with the motor support portion 51a in front of the motor support portion 51a. That is, the crank accommodating portion 51b and the motor support portion 51a are formed continuously from a single material. The crank accommodating portion 51b includes a left wall portion 51b1 and a right wall portion 51b2 that are arranged opposite to each other in the left-right direction of the electric hammer 10.

[0095] A flat wall portion 51b3 is provided behind the crank housing portion 51b, and the flat wall portion 51b3 extends in the left-right direction of the electric hammer 10 and connects the rear sides of the left side wall portion 51b1 and the right side wall portion 51b2. When the electric hammer 10 is assembled, the flat abutment portion 30a1 (see FIG. 6) provided on the motor case 30 abuts against the outer side (rear side) of the flat wall portion 51b3.

[0096] As a result, the motor case 30, with the mating cylindrical portion 30b mated with the cylindrical mounting portion 51a1 and the flat abutment portion 30a1 abutting against the flat wall portion 51b3, is unable to rotate relative to the second case body 51 and can be positioned in the correct position.

[0097] Furthermore, a case fixing part 51b4 is provided in front of the crank housing part 51b, and a connecting rod insertion hole 51b5 through which a connecting rod 54 forming the striking unit 53 can be inserted is provided in the case fixing part 51b4. The case fixing part 51b4 extends in the left-right direction of the electric hammer 10 and connects the front sides of the left side wall part 51b1 and the right side wall part 51b2. The rear side of the striking unit case 52 in the longitudinal direction is connected to the outer side (front side) of the case fixing part 51b4 when the electric hammer 10 is assembled.

[0098] Furthermore, a fixing surface portion 51b6 is provided on the first support case 40 side (upper side) of the crank housing portion 51b. The first support surface 41a of the first case body 41 abuts against the fixing surface portion 51b6 when the electric hammer 10 is in an assembled state. That is, the first support case 40 made of metal and the second support case 50 made of metal abut against each other in the up-down direction of the electric hammer 10 (the axial direction of the output shaft 33a). Therefore, the first and second support cases 40, 50 can be firmly fixed to each other.

[0099] Therefore, the motor case 30, which is supported (clamped) so as to be sandwiched between the first case body 41 and the second case body 51, is firmly fixed to both the first support case 40 and the second support case 50 without any rattling.

[0100] 3, a bottom surface portion 51b7 is provided below the crank accommodating portion 51b. The bottom surface portion 51b7 closes the lower side of the crank accommodating portion 51b. Here, the bottom surface portion 51b7 is provided with a through hole 51b8 that penetrates in the up-down direction, and the through hole 51b8 is closed with a rubber closing cap CP. The through hole 51b8 is a hole for passing a set screw S2 that attaches the longitudinal base end side of the connecting rod 54 to the crank pin 44a.

[0101] <Assembly Instructions> Next, an example of an assembly procedure (assembly method) for the electric hammer 10 formed as above will be described in detail with reference to the drawings.

[0102] FIG. 9 is a diagram explaining the assembly procedure (1) of the electric hammer, FIG. 10 is a diagram explaining the assembly procedure (2) of the electric hammer, and FIG. 11 is a diagram explaining the assembly procedure (3) of the electric hammer.

[0103] First, as shown in FIG. 9, a gear mechanism assembly GA, a rotor assembly RA, a motor case assembly MA and an impact mechanism assembly BA are prepared.

[0104] The gear mechanism assembly GA is formed by previously mounting the first ball bearing B1 to the first case body 41 in a separate assembly process, mounting the small diameter gear G1 having the third and fourth ball bearings B3 and B4 mounted thereon, and mounting the crankshaft 44 having the fifth and sixth ball bearings B5 and B6 and the large diameter gear G2 mounted thereon.

[0105] The rotor assembly RA corresponds to the rotor 33, and is obtained by previously mounting the rotor core 33b, the rotor coil 33c, the commutator 33d, the cooling fan FN, and the second ball bearing B2 to the output shaft 33a in a separate assembly process.

[0106] Furthermore, the motor case assembly MA is a product in which the stator 32 is attached inside the motor case 30 in advance in a separate assembly process.

[0107] The striking mechanism assembly BA is formed by attaching a striking unit 53 to a striking unit case 52 forming the second support case 50 in a separate assembly process.

[0108] Then, as shown by arrow M1, the motor case assembly MA is brought from above into contact with the motor support portion 51a of the second case body 51. Next, the fitting cylindrical portion 30b of the motor case 30 is fitted into the cylindrical mounting portion 51a1 of the motor support portion 51a. At this time, as shown by arrow M2, the electric wires EL are pulled out rearward.

[0109] Thereafter, as shown by the arrow M3, the rotor assembly RA is inserted radially inside the stator 32. At this time, the second ball bearing B2 side of the rotor assembly RA in the axial direction faces downward. Then, the second ball bearing B2 of the rotor assembly RA is attached to the sixth bearing attachment portion 51a3 of the second case body 51. This results in the state shown in FIG.

[0110] Next, as shown by arrow M4, the gear mechanism assembly GA is butted against the motor case 30 and the second case body 51. At this time, the first support surface 41a of the first case body 41 is butted against the abutment surface portion 30a5 of the motor case 30 and the fixing surface portion 51b6 of the second case body 51.

[0111] Then, one axial side (upper side) of the output shaft 33a is passed through the first ball bearing B1 to mesh the pinion gear PG with the small diameter gear G1. Also, the crank pin 44a is inserted into the needle roller bearing B7 provided on the longitudinal base end side of the connecting rod 54. This results in the state shown in FIG.

[0112] 10, the cover member 42 and a plurality of screw members S1 are prepared, along with a closing cap CP and a set screw S2. Also, a motor cover MC made of a resin material such as plastic and a cover screw S3 are prepared.

[0113] Then, as shown by arrow M5, the cover member 42 is attached to the first case body 41. At this time, the abutting portion 42a of the cover member 42 is abutted against the second support surface 41b of the first case body 41. Next, the third ball bearing B3 is attached to the fourth bearing attachment portion 42b, and the fifth ball bearing B5 is attached to the fifth bearing attachment portion 42c.

[0114] Thereafter, the first support case 40 is fixed to the second support case 50 by a plurality of screw members S1. As a result, the motor case 30 is sandwiched between the first case body 41 and the second case body 51, and is fixed to both the first support case 40 and the second support case 50.

[0115] Then, as shown by arrow M6, a setscrew S2 is passed through the through hole 51b8, and a tightening jig (not shown) such as a hexagonal wrench is used to fix the base end side of the longitudinal direction of the connecting rod 54 to the crank pin 44a. Next, a blocking cap CP is attached to the through hole 51b8 to block the through hole 51b8.

[0116] Thereafter, as shown by arrow M7, the motor cover MC is attached to the underside of the motor support part 51a that forms the second case body 51, and the motor cover MC is fixed to the second case body 51 by the cover screw S3. This prevents the second ball bearing B2 from being soiled by dust or the like.

[0117] Then, as shown in FIG. 11, the back cover 60 and a plurality of screw members S1 are prepared, the vibration reduction mechanism 76 and fixing screws S4 are prepared, and the handle 70 and side handle SH are prepared.

[0118] Next, as shown by arrow M8, the back cover 60 is placed from the rear side of the motor case 30 and fixed to the first support case 40 and the second support case 50 with a plurality of screw members S1. Thereafter, as shown by arrow M9, the vibration reduction mechanism 76 is placed from the rear side of the back cover 60 and fixed to the first support case 40 with fixing screws S4.

[0119] Then, as shown by arrow M10, the handle 70 is attached from the rear side of the back cover 60. At this time, the upper connecting portion 72 of the handle 70 is fixed to the rear side of the vibration reduction mechanism 76. In addition, the lower connecting portion 73 of the handle 70 is rotatably attached to the shaft support portion 51a4 via the rotation shaft PS (see FIG. 3).

[0120] Thereafter, as shown by an arrow M11, the side handle SH is attached to the striking unit case 52. This completes the assembly of the electric hammer 10.

[0121] As described above in detail, according to the electric hammer 10 of this embodiment, the housing 20 includes a resin motor case 30 that extends in the axial direction of the output shaft 33a and supports the electric motor 31 internally, and first and second metal support cases 40, 50 that have a first support surface 41a that supports one axial side of the motor case 30 and a cylindrical mounting portion 51a1 that supports the other axial side of the motor case 30, and that internally support the gear mechanism 43, the crankshaft 44 and the striking unit 53.

[0122] This allows the electric motor 31 to be supported only by the plastic motor case 30, and allows both axial ends of the motor case 30 to be supported by the first and second support cases 40, 50, which have high rigidity. This prevents the weight of the electric hammer 10 from increasing compared to the past, and prevents the electric hammer 10 from becoming larger. This improves the operability of the electric hammer 10. In addition, because rattling of the plastic motor case 30 can be prevented, it is possible to improve the durability of the electric hammer 10 while improving its operability.

[0123] Furthermore, according to the electric hammer 10 according to this embodiment, the motor case 30 has at least a portion of the outer circumferential surface thereof exposed to the outside.

[0124] This makes it possible to increase the variety of the electric hammer 10 while improving the design of the electric hammer 10 by preparing motor cases 30 of different colors.

[0125] Furthermore, the electric hammer 10 according to this embodiment has the first support case 40 and the second support case 50 made of metal.

[0126] This allows the motor case 30 to be sandwiched between the first support case 40 and the second support case 50 when they are assembled together, thereby improving the ease of assembly of the electric hammer 10.

[0127] Furthermore, according to the electric hammer 10 according to this embodiment, the first support case 40 and the second support case 50 are butted against each other in the axial direction of the output shaft 33a.

[0128] As a result, the first and second support cases 40, 50 that are butted against each other can be firmly fixed to each other because they are both made of metal, and the motor case 30 that is sandwiched between them can be made less loose, thereby further improving the durability of the electric hammer 10 and workability.

[0129] Furthermore, the electric hammer 10 according to this embodiment has a gear mechanism 43 supported by the first support case 40 and an impact unit 53 supported by the second support case 50, and the gear mechanism 43 is connected to the impact unit 53 so as to be capable of transmitting power thereto by a crankshaft 44 extending in the axial direction of the output shaft 33a.

[0130] This allows the output shaft 33a and the crankshaft 44 to be arranged parallel to each other, and prevents the output shaft 33a of the electric hammer 10 from becoming large in the axial direction (vertical direction). This allows the electric hammer 10 to be made compact, and workability can be improved.

[0131] In addition, according to the electric hammer 10 of this embodiment, an opening 30a4 and a plurality of air holes H that connect the inside and outside of the motor case 30 are provided on one axial side and the other axial side of the motor case 30, and the first and second support cases 40, 50 cover the opening 30a4 and the plurality of air holes H.

[0132] This effectively prevents dust and other particles from entering the interior of the motor case 30, thereby enabling the electric motor 31 to operate smoothly for a long period of time.

[0133] Furthermore, according to the electric hammer 10 of this embodiment, the electric motor 31 includes the stator 32 fixed to the motor case 30, and the rotor 33 rotatably supported by the first and second support cases 40, 50.

[0134] This makes it possible to stably rotate the output shaft 33a while reducing the weight of the motor case 30. Therefore, the durability of the electric hammer 10 can be improved while improving the workability.

[0135] In addition, according to the electric hammer 10 of this embodiment, the gear mechanism 43, the crankshaft 44 and the impact unit 53 are supported by the first and second support cases 40, 50 so as to overlap with the electric motor 31 in a direction (front-back direction) intersecting the axial direction (up-down direction) of the output shaft 33a.

[0136] This makes it possible to prevent the electric hammer 10 from becoming large in the vertical direction (axial direction of the output shaft 33a).

[0137] Furthermore, according to the electric hammer 10 of this embodiment, the housing 20 has a handle 70 arranged to overlap the electric motor 31 in a direction (front-rear direction) intersecting the axial direction (up-down direction) of the output shaft 33a.

[0138] As a result, the relatively heavy electric motor 31 is disposed in front of the handle 70 (toward the target object such as concrete or stone), and the weight balance of the electric hammer 10 can be optimized with respect to the working posture of the worker, thereby improving workability.

[0139] In addition, according to the electric hammer 10 of this embodiment, the handle 70 is formed in a rod shape extending in the axial direction (up and down direction) of the output shaft 33a, and both longitudinal sides of the handle 70 are supported by the first and second support cases 40, 50.

[0140] This allows the trigger switch 75 to be located in front of the handle 70, and allows the operator's fingers to be placed in the space in front of the handle 70. This makes it easier to hold the electric hammer 10, improving operability.

[0141] Furthermore, according to the electric hammer 10 of this embodiment, one longitudinal side (upper side) of the handle 70 is movable relative to the first support case 40 in a direction (front-to-back direction) intersecting the axial direction (up-down direction) of the output shaft 33a, and the other longitudinal side (lower side) of the handle 70 is rotatable around a pivot axis PS attached to the second support case 50.

[0142] This allows the handle 70 to swing about the pivot shaft PS when the electric hammer 10 is operated. This makes it difficult for vibrations generated by the electric hammer 10 to be transmitted to the handle 70 (operator), making it possible to protect the operator from the vibrations.

[0143] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the working machine of the present invention is not limited to the electric hammer 10 that strikes the tool 11 as described above, but can also be applied to other working machines such as a hammer drill that can strike the tool while rotating it.

[0144] Furthermore, the material, shape, size, number, installation location, etc. of each component in the above-described embodiment may be arbitrary as long as it achieves the present invention, and is not limited to the above-described embodiment. [Explanation of symbols]

[0145] 10...electric hammer (working machine), 11...tool, 20...housing, 30...motor case, 30a...cylindrical main body, 30a1...flat abutment portion, 30a2...exposed portion, 30a3...arc-shaped wall portion, 30a4...opening (first opening), 30a5...abutment surface portion, 30b...fitting cylindrical portion, 30b1...side wall portion, 30b2...brush holder insertion hole, 30b3...bottom wall portion, 31...electric motor (motor), 32...stator, 32a...stator core, 32b... stator coil, 33... rotor, 33a... output shaft, 33b... rotor core, 33c... rotor coil, 33d... commutator, 40... first support case (support case), 41... first case body, 41a... first support surface (first support portion), 41b... second support surface, 41c... first bearing mounting portion, 41d... second bearing mounting portion, 41e... third bearing mounting portion, 42... cover member, 42a... abutment portion, 42b... third bearing mounting portion 4 bearing mounting portion, 42c...fifth bearing mounting portion, 42d...recessed portion, 42e...side wall, 42f...bottom wall, 42g...support protrusion, 43...gear mechanism (operating portion, first operating portion), 44...crankshaft (operating portion, connecting member), 44a...crank pin, 44b...female thread portion, 50...second support case (support case), 51...second case main body, 51a...motor support portion, 51a1...cylindrical mounting portion (second support portion), 51a2 ...Closed bottom portion, 51a3...6th bearing mounting portion, 51a4...shaft support portion, 51a5...shaft mounting hole, 51a6...brush holder fixing hole, 51b...crank housing portion, 51b1...left side wall portion, 51b2...right side wall portion, 51b3...flat wall portion, 51b4...case fixing portion, 51b5...connecting rod insertion hole, 51b6...fixing surface portion, 51b7...bottom surface portion, 51b8...through hole, 52...striking unit case, 53...striking unit (operating portion,second operating portion), 54... connecting rod, 54a... piston pin, 55... piston, 55a... annular seal, 56... striker, 56a... cylindrical portion, 56b... bottom portion, 56c... opening, 57... hammer member, 58... air damper chamber, 59... hammer guide, 60... back cover, 61... motor case covering portion, 62... first support case covering portion, 63... second support case covering portion, 70... handle, 71... handle body, 72... upper connecting portion, 73... lower connecting portion, 74... limit switch, 75... trigger switch, 76... vibration reduction mechanism, 76a... damper member, 76b... spring, B1... first ball bearing, B2... second ball bearing, B 3...3rd ball bearing, B4...4th ball bearing, B5...5th ball bearing, B6...6th ball bearing, B7...needle roller bearing, BA...impact mechanism assembly, BC...brush cap, CP...blocking cap, EL...electric wire, FN...cooling fan, G1...small diameter gear, G2...large diameter gear, GA...gear mechanism assembly, H...ventilation hole (second opening), HD...tool holder, MA...motor case assembly, MC...motor cover, PG...pinion gear, PS...rotating shaft, RA...rotor assembly, S1...screw member, S2...set screw, S3...cover screw, S4...fixing screw, SH...side handle, ST...stopper member,

Claims

1. a motor having an output shaft; an operating portion that operates by rotation of the output shaft; a housing that accommodates the motor and the actuator; Equipped with The housing includes: a motor case made of resin that extends in the axial direction of the output shaft and supports the motor therein; a metal support case having a first support portion supporting one axial side of the motor case and a second support portion supporting the other axial side of the motor case, the metal support case supporting the operating portion therein; Equipped with Work machine.

2. At least a portion of an outer circumferential surface of the motor case is exposed to the outside. The work machine according to claim 1.

3. The support case includes: a first support case having the first support portion; a second support case having the second support portion; Including, The work machine according to claim 1.

4. The first support case and the second support case are butted against each other in the axial direction of the output shaft. The work machine according to claim 3.

5. The actuation unit includes: a first operating portion supported by the first support case; a second operating portion supported by the second support case; having The first operating portion is connected to the second operating portion by a connecting member extending in the axial direction of the output shaft so as to be capable of transmitting power. A work machine according to claim 3 or claim 4.

6. a first opening and a second opening are provided on one axial side and the other axial side of the motor case, respectively, to communicate between the inside and the outside of the motor case; The support case covers the first opening and the second opening. The work machine according to claim 1.

7. The motor is A stator fixed to the motor case; a rotor rotatably supported by the support case; Equipped with A work machine according to claim 1 or 6.

8. The actuator is supported by the support case so as to overlap with the motor in a direction intersecting an axial direction of the output shaft. The work machine according to claim 1.

9. The housing has a handle arranged to overlap the motor in a direction intersecting an axial direction of the output shaft. The work machine according to claim 1.

10. The handle is formed in a rod shape extending in the axial direction of the output shaft, and both longitudinal sides of the handle are supported by the support case. A work machine according to claim 9.

11. A longitudinal direction of the handle is movable relative to the support case in a direction intersecting an axial direction of the output shaft, The other side of the handle in the longitudinal direction is rotatable about a rotation axis attached to the support case. A work machine according to claim 10.

Images