Work machine

Abstract

The present invention improves the convenience of a work machine. A hammer drill 1A comprises: a motor 10; a first shaft 41; a second shaft 42; a first gear 51 which receives the driving force of the motor 10 and rotates about the central axis of the first shaft 41; a crank 55 which rotates integrally with the first gear 51 about the central axis of the first shaft 41; an operation mechanism 60 which operates a drill bit 7 in accordance with the rotation of the crank 55; a second gear 52 which receives the driving force of the motor 10 and rotates about the central axis of the second shaft 42; and a case part 20 which defines a first housing chamber 31 and a second housing chamber 32 that are independent of each other. The first gear 51 is housed in the first housing chamber 31, and the first shaft 41 is disposed to straddle the first housing chamber 31 and the second housing chamber 32.

Description

Work equipment

[0001] The present invention relates to a work machine, and more particularly to an electric work machine.

[0002] Various electric work machines using a motor as a drive source are known. For example, Patent Document 1 discloses a hammer drill using a motor as a drive source. This hammer drill has a housing chamber that houses multiple gears, including a first gear that meshes with the output shaft of the motor, and a housing chamber that houses a crank mechanism, a cylinder, etc., which are independently defined. Furthermore, each housing chamber is filled with a lubricant.

[0003] The hammer drill disclosed in Patent Document 1 requires a large capacity housing chamber to accommodate multiple gears, including the first gear. However, increasing the capacity of the housing chamber can lead to uneven distribution of lubricant away from the first gear, which is most in need of lubrication, potentially resulting in insufficient lubrication of the first gear. Furthermore, this can increase the frequency and number of maintenance work required for the first gear.

[0004] JP 2015-116651 A

[0005] It is desirable to improve the convenience of work machines by reducing the frequency and number of times gear maintenance is required.

[0006] In one embodiment, a work machine includes a motor, a first shaft, a second shaft, a first gear that receives driving force from the motor and rotates about a central axis of the first shaft, an output unit that rotates integrally with the first gear about the central axis of the first shaft, an actuation mechanism that actuates a tool bit in accordance with the rotation of the output unit, a second gear that receives driving force from the motor and rotates about a central axis of the second shaft, and a case that defines a first housing chamber and a second housing chamber that are independent of each other. The first gear is accommodated in the first housing chamber, and the second shaft, the second gear, the output unit, and the actuation mechanism are accommodated in the second housing chamber. The first shaft is disposed across the first housing chamber and the second housing chamber.

[0007] According to the present invention, a work machine with improved convenience can be provided.

[0008] Fig. 1 is an explanatory diagram showing the structure of a hammer drill according to a first embodiment. Fig. 2 is a partially enlarged view showing a case portion and its periphery shown in Fig. 1. Fig. 3 is an exploded perspective view showing a case portion 20 shown in Fig. 1 and its interior. Fig. 4 is an explanatory diagram showing the structure of a hammer drill according to a second embodiment.

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all drawings used to explain the embodiments, the same reference numerals are used for the same or substantially the same configurations and elements. Furthermore, as a general rule, once a configuration or element has been explained, it will not be explained again.

[0010] (Embodiment 1) <Outline of the Work Machine According to the Present Embodiment> The work machine according to the present embodiment is an impact tool generally known as a "hammer drill." Hammer drills are suitable for drilling holes in mating materials such as concrete and stone, and for crushing mating materials.

[0011] 1 is an explanatory diagram showing the structure of a hammer drill 1A according to this embodiment. The hammer drill 1A has a synthetic resin housing 2. The housing 2 is composed of a main housing 3, a motor housing 4, and a handle housing 5.

[0012] The handle housing 5 is disposed behind the main housing 3 and the motor housing 4, and straddles the main housing 3 and the motor housing 4. More specifically, one end of the handle housing 5 is connected to the upper rear surface of the main housing 3 via a vibration isolation mechanism 6, and the other end of the handle housing 5 is rotatably connected to the lower rear surface of the motor housing 4.

[0013] A drill bit 7 is attached to the hammer drill 1A as a tool tip. The driving force output from the motor 10 in the motor housing 4 passes through a power transmission path described below and is finally input (applied) to the drill bit 7. More specifically, the driving force output from the motor 10 is converted into an impact force or a rotational force and applied to the drill bit 7.

[0014] The hammer drill 1A has a "hammer mode" in which a striking force is applied to the drill bit 7, and a "hammer drill mode" in which a striking force and a rotational force are applied to the drill bit 7. These two operating modes can be switched in response to an operator's operation.

[0015] For ease of explanation, the longitudinal direction of the drill bit 7 shown in Fig. 1 is defined as the front-rear direction. However, the tool bit attached to the hammer drill 1A is not limited to the drill bit 7. The tool bit attached to the hammer drill 1A can be selected depending on the type of workpiece, the details of the work, etc.

[0016] <Motor> The motor 10 housed in the motor housing 4 is a brushless motor. The motor 10 is powered by electricity supplied via a power cord 8 extending from the bottom end of the handle housing 5. Although not shown, the end of the power cord 8 is provided with a plug that can be connected to a commercial power source or a generator.

[0017] An output shaft 11 of the motor 10 is rotatably supported by bearings 12 and 13. More specifically, one end of the output shaft 11 is rotatably supported by the bearing 12, and the other end of the output shaft 11 is rotatably supported by the bearing 13.

[0018] For ease of explanation, the axial direction (longitudinal direction) of the output shaft 11 is defined as the up-down direction. Furthermore, one end of the output shaft 11 supported by the bearing 12 is defined as the "lower side" or "downward," and the other end of the output shaft 11 supported by the bearing 13 is defined as the "upper side" or "upward."

[0019] The upper end of the output shaft 11 passes through the bearing 13 and the motor housing 4 and enters the inside of the main housing 3. From another perspective, the upper end of the output shaft 11 is located inside the main housing 3. A pinion gear 14 is provided on the upper end of the output shaft 11 located inside the main housing 3.

[0020] <Case> A case 20 is provided inside the main housing 3. Fig. 2 is a partially enlarged view showing the case 20 and its surroundings. Fig. 3 is an exploded perspective view showing the case 20 and its interior.

[0021] The case 20 is composed of a main body 21, a bottom 22, a first lid 23a, a second lid 23b, and a cylindrical portion 24. The main body 21, the bottom 22, the second lid 23b, and the cylindrical portion 24 are all made of metal, and the first lid 23a is made of resin. The components of the case 20 are fixed to each other and integrated.

[0022] For example, the bottom portion 22 is screwed to the bottom surface of the main body portion 21, and the cylindrical portion 24 is screwed to the front surface of the main body portion 21. The second lid portion 23b is screwed to the top surface of the main body portion 21, and the first lid portion 23a is fitted and fixed to the second lid portion 23b so as to be rotatable relative to the second lid portion 23b. The first lid portion 23a rotates relative to the second lid portion 23b to change the operating mode of the operating mechanism 60, thereby functioning as a change lever that switches the operating mode of the hammer drill 1A.

[0023] 3, the first lid portion 23a, the second lid portion 23b, and the cylindrical portion 24 are omitted. In the following description, the first lid portion 23a and the second lid portion 23b may be collectively referred to as the "lid portion 23."

[0024] 2, the case 20 defines therein a first storage chamber 31 and a second storage chamber 32. More specifically, the first storage chamber 31 is defined between the main body 21 and a bottom 22 fixed to the bottom surface of the main body 21.

[0025] 3, a recess 31a is provided at the rear of the main body 21, and a recess 31b is provided at the rear of the bottom 22. When the bottom 22 is fixed to the bottom surface of the main body 21, the recess 31a and the recess 31b are butted together, forming a first storage chamber 31 therebetween.

[0026] Referring again to Figure 2, a second storage chamber 32 is defined inside the main body 21, the lid 23 fixed to the top surface of the main body 21, and the cylindrical portion 24 fixed to the front surface of the main body 21. A sealing member is disposed between the main body 21 and the lid 23, and a sealing member is also disposed between the main body 21 and the cylindrical portion 24.

[0027] The first storage chamber 31 is separated from the second storage chamber 32 by the bottom wall 25 of the main body 21. In other words, the first storage chamber 31 and the second storage chamber 32 are independent of each other. In other words, the bottom wall 25 of the main body 21 is a partition wall that separates the first storage chamber 31 and the second storage chamber 32. Therefore, in the following description, the bottom wall 25 of the main body 21 may be referred to as the "partition wall 25."

[0028] As mentioned above, the upper end of the output shaft 11 of the motor 10 is located inside the main housing 3, but more specifically, the upper end of the output shaft 11 is located inside the case portion 20.

[0029] Specifically, the upper end of the output shaft 11 penetrates the bottom 22 of the case 20 and enters the first housing chamber 31. As a result, the pinion gear 14 provided at the upper end of the output shaft 11 is located inside the first housing chamber 31.

[0030] <Shafts> A rotatable first shaft 41 and a second shaft 42 are provided inside the case 20. The first shaft 41 and the second shaft 42 are parallel to each other. The first shaft 41 and the second shaft 42 are also parallel to the output shaft 11 of the motor 10. In other words, the output shaft 11, the first shaft 41, and the second shaft 42 are parallel to each other.

[0031] Furthermore, the output shaft 11 is disposed between the first shaft 41 and the second shaft 42 in the front-rear direction. More specifically, the first shaft 41 is disposed rearward of the output shaft 11, and the second shaft 42 is disposed forward of the output shaft 11.

[0032] The first shaft 41 penetrates the partition wall 25 and straddles the first storage chamber 31 and the second storage chamber 32. In addition, one end (lower end) of the first shaft 41 is rotatably supported by a sliding bearing 43 held in the bottom portion 22, and the other end (upper end) of the first shaft 41 is rotatably supported by a rolling bearing 44 provided inside the main body portion 21 (second storage chamber 32).

[0033] The entire second shaft 42 is disposed inside the main body 21 (second housing chamber 32). In other words, the second shaft 42 does not pass through the partition wall 25. More specifically, a portion (lower portion) of the second shaft 42 is inserted into a recess 26 formed in the second housing chamber 32 by the partition wall 25, and another portion (upper portion) of the second shaft 42 protrudes from the recess 26. Furthermore, a bevel gear 45 is provided at the upper end of the second shaft.

[0034] <Gears> A plurality of gears are housed in the case portion 20. More specifically, at least a first gear 51, a second gear 52, and a third gear 53 are housed in the case portion 20. The first gear 51 is housed in the first housing chamber 31. On the other hand, the second gear 52 and the third gear 53 are housed in the second housing chamber 32.

[0035] The first gear 51 housed in the first housing chamber 31 is fixed to the first shaft 41. The first gear 51 also meshes with the pinion gear 14 provided on the output shaft 11 of the motor 10 within the first housing chamber 31.

[0036] Therefore, the first shaft 41 and the first gear 51 rotate integrally when the output shaft 11 of the motor 10 rotates. From another perspective, the first gear 51 receives the driving force of the motor 10 and rotates within the first housing chamber 31 around the central axis A of the first shaft 41.

[0037] The second gear 52 housed in the second housing 32 is fixed to the second shaft 42. More specifically, the second gear 52 is fixed to the upper part of the second shaft 42 protruding from the recess 26 via a slip clutch.

[0038] The third gear 53 housed in the second housing chamber 32 is fixed to the first shaft 41. Therefore, the third gear 53, like the first gear 51, rotates about the central axis A of the first shaft 41. From another perspective, the first gear 51 and the third gear 53 are provided on a common shaft and rotate integrally.

[0039] However, the third gear 53 is provided above the first gear 51 in the direction of the central axis A of the first shaft 41, and rotates within the second housing chamber 32. Furthermore, the third gear 53 meshes with the second gear 52 within the second housing chamber 32. Therefore, when the third gear 53 rotates, the second gear 52 and the second shaft 42 to which the second gear 52 is fixed rotate integrally.

[0040] From another perspective, the driving force of the motor 10 is transmitted to the second gear 52 via the first gear 51, the first shaft 41, and the third gear 53. As a result, the second gear 52 receives the driving force of the motor 10 and rotates within the second housing chamber 32 around the central axis B of the second shaft 42.

[0041] As described above, the third gear 53 is provided above the first gear 51 in the direction of the central axis A of the first shaft 41. On the other hand, the motor 10 is provided below the first gear 51 in the direction of the central axis A of the first shaft 41. In other words, in the direction of the central axis A of the first shaft 41, the third gear 53 is disposed on one side (upper side) of the first gear 51, and the motor 10 is disposed on the other side (lower side) of the first gear 51.

[0042] <Output Unit> A crank 55 serving as an output unit is provided in the second housing chamber 32. The crank 55 is fixed to the upper end of the first shaft 41, and rotates integrally with the first gear 51 and the third gear 53 around the central axis A of the first shaft 41.

[0043] <Operating Mechanism> An operating mechanism 60 that operates the drill bit 7 in response to rotation of the crank 55 is provided in the second housing chamber 32. As shown in Figure 1, the operating mechanism 60 has a cylinder 61, a piston 62, a striker 63, and an intermediate element 64.

[0044] The cylinder 61 extends in a direction intersecting the direction of the central axis A of the first shaft 41 and the direction of the central axis B of the second shaft 42 shown in Fig. 2. More specifically, the cylinder 61 extends in a direction perpendicular to the direction of the central axis A of the first shaft 41 and the direction of the central axis B of the second shaft 42. In short, the cylinder 61 extends in the front-rear direction. Furthermore, the cylinder 61 is rotatable around its central axis.

[0045] The piston 62, the striker 63, and the intermediate element 64 are housed in the cylinder 61. Furthermore, the piston 62, the striker 63, and the intermediate element 64 are arranged in a line in this order, and the piston 62 can reciprocate inside the cylinder 61 in the longitudinal direction of the cylinder 61 (front-to-back direction).

[0046] The piston 62 is connected to the crank 55 and reciprocates within the cylinder 61 as the crank 55 rotates. In other words, when the crank 55 rotates, the piston 62 reciprocates linearly. From another perspective, the crank 55 is a motion conversion mechanism that converts rotational motion into linear reciprocating motion.

[0047] The striker 63 is disposed in front of the piston 62, and an air chamber is formed between the piston 62 and the striker 63. When the piston 62 reciprocates back and forth within the cylinder 61, the pressure in the air chamber fluctuates. The pressure fluctuations in the air chamber then drive the striker 63, which strikes the intermediate element 64, which in turn strikes the drill bit 7. As a result, a striking force is applied to the drill bit 7.

[0048] 2, a sleeve 65 and a slider 66 are provided around the cylinder 61. The sleeve 65 has a bevel gear 65a that meshes with the bevel gear 45 provided at the upper end of the second shaft 42. The slider 66 can advance and retreat relative to the sleeve 65.

[0049] The sleeve 65 can rotate in the circumferential direction of the cylinder 61, but cannot move in the axial direction (front-rear direction) of the cylinder 61. On the other hand, the slider 66 can move in the axial direction (front-rear direction) of the cylinder 61, but cannot rotate in the circumferential direction of the cylinder 61. Furthermore, the slider 66 engages with the sleeve 65 when it moves rearward, and disengages from the sleeve 65 when it moves forward.

[0050] Therefore, when the slider 66 is moved rearward and engaged with the sleeve 65, the rotation of the second shaft 42 is transmitted to the cylinder 61 via the sleeve 65 and the slider 66. Then, the cylinder 61 rotates around its own central axis. As a result, a rotational force is applied to the drill bit 7 in addition to an impact force.

[0051] On the other hand, when the slider 66 is moved forward and released from the sleeve 65, the rotation of the second shaft 42 is no longer transmitted to the cylinder 61. As a result, only a striking force is applied to the drill bit 7. At this time, the sleeve 65 rotates idly around the cylinder 61.

[0052] From another perspective, the "hammer drill mode" is selected when the slider 66 is retracted and engaged with the sleeve 65, and the "hammer mode" is selected when the slider 66 is advanced and disengaged from the sleeve 65. In other words, the operating mode of the hammer drill 1A is switched by advancing and retracting the slider 66.

[0053] The bevel gear 45, which rotates integrally with the second gear 52 around the central axis B of the second shaft 42, is an example of a fourth gear. The bevel gear 65a, which meshes with the bevel gear 45 and rotates integrally with the cylinder 61, is an example of a fifth gear.

[0054] <Lubricant> As described above, the hammer drill 1A according to this embodiment includes a first power transmission path that transmits the driving force of the motor 10 to the piston 62 and a second power transmission path that transmits the driving force of the motor 10 to the cylinder 61. The first gear 51 serves as both an input gear and a first gear in both power transmission paths. Therefore, the first gear 51 is subject to greater wear than the other moving parts, including the second gear 52 and the third gear 53, and is therefore in particular in need of lubrication.

[0055] Therefore, in the hammer drill 1A of this embodiment, two independent storage chambers are defined, and one storage chamber (first storage chamber 31) contains only the first gear 51, while the other storage chamber (second storage chamber 32) contains movable members other than the first gear 51 (second gear 52, third gear 53, crank 55, operating mechanism 60, etc.).

[0056] Furthermore, each of the storage chambers is filled with a lubricant (grease) having different properties. More specifically, the first storage chamber 31 is filled with a grease having a higher viscosity than the grease filled in the second storage chamber 32.

[0057] From another perspective, the hammer drill 1A of this embodiment is provided with a dedicated storage chamber (first storage chamber 31) that is filled with grease that is optimal for lubricating the first gear 51 and that accommodates only the first gear 51.

[0058] The first housing chamber 31, which houses only the first gear 51, only needs to have a volume large enough to house the first gear 51. Therefore, the volume of the first housing chamber 31 can be made as small as possible. As a result, a sufficient amount of grease is maintained around the first gear 51 at all times, reducing the number of maintenance operations and the frequency of maintenance of the first gear 51.

[0059] <Sealing Member> As described above, the grease filled in the first storage chamber 31 and the grease filled in the second storage chamber 32 have different properties. Specifically, the grease filled in the second storage chamber 32 has a lower viscosity and a higher fluidity than the grease filled in the first storage chamber 31. For this reason, there is a risk that the grease filled in the second storage chamber 32 will flow out of the second storage chamber 32 and into the first storage chamber 31.

[0060] More specifically, in this embodiment, the first shaft 41 passes through the partition wall 25 and straddles the first storage chamber 31 and the second storage chamber 32. Therefore, there is a risk that grease may pass between the first shaft 41 and the partition wall 25 and flow into the first storage chamber 31.

[0061] Therefore, a seal member 70 is provided between the first shaft 41 and the partition wall 25. Since the second shaft 42 does not pass through the partition wall 25, no seal member is provided between the second shaft 42 and the partition wall 25.

[0062] The seal member 70 is an annular packing with a lip, and is generally called a “seal ring.” The seal member 70 is provided around the first shaft 41 and prevents the lubricant in the second housing chamber 32 from flowing along the first shaft 41 into the first housing chamber 31.

[0063] As described above, sealing members are also disposed between the main body 21 and the lid 23 and between the main body 21 and the cylindrical portion 24. As a result, the second storage chamber 32 is substantially hermetically sealed by a plurality of sealing members including the sealing member 70.

[0064] From another perspective, the first housing chamber 31 is adjacent to the second housing chamber 32, but is airtightly separated from the second housing chamber 32 by the seal member 70. In other words, the first housing chamber 31 and the second housing chamber 32 are independent of each other so that no movement of the lubricant occurs.

[0065] (Embodiment 2) The work machine according to this embodiment is a hammer drill similar to the hammer drill 1A according to Embodiment 1. Therefore, a description of the same or substantially the same configuration as the hammer drill 1A according to Embodiment 1 will be omitted, and only the different configuration will be described.

[0066] 4 is an explanatory diagram showing the structure of a hammer drill 1B according to this embodiment. In the hammer drill 1A, a third gear 53 is provided on the first shaft 41. In contrast, in the hammer drill 1B, the third gear 53 is not provided on the first shaft 41.

[0067] In the hammer drill 1A, the output shaft 11 of the motor 10 does not pass through the partition wall 25. On the other hand, in the hammer drill 1B, the output shaft 11 of the motor 10 passes through the partition wall 25 and enters the second housing chamber 32.

[0068] Furthermore, a second pinion gear 15 is provided at the tip of the output shaft 11 that enters the second housing chamber 32. This second pinion gear 15 meshes with a second gear 52 within the second housing chamber 32.

[0069] That is, in the hammer drill 1A, the driving force of the motor 10 is input to the second gear 52 via the third gear 53. On the other hand, in the hammer drill 1B, the driving force of the motor 10 is input directly to the second gear 52 via the second pinion gear 15. Note that in the hammer drill 1B as well, the first gear 51 is housed in the first housing chamber 31 and meshes with the pinion gear 14 within the first housing chamber 31.

[0070] In the present embodiment in which the output shaft 11 passes through the partition wall 25, a seal member 71 similar to the seal member 70 is provided between the output shaft 11 and the partition wall 25. The seal member 71 is disposed between the pinion gear 14 and the second pinion gear 15 in the longitudinal direction (axial direction / up-down direction) of the output shaft 11.

[0071] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit and scope of the present invention.

[0072] DESCRIPTION OF SYMBOLS 1A, 1B...Hammer drill, 2...Housing, 3...Main housing, 4...Motor housing, 5...Handle housing, 6...Vibration-damping mechanism, 7...Drill bit, 8...Power cord, 10...Motor, 11...Output shaft, 12, 13...Bearings, 14...Pinion gear, 15...Second pinion gear, 20...Case portion, 21...Main body portion, 22...Bottom portion, 23...Cover portion, 23a...First cover portion, 23b...Second cover portion, 24...Cylindrical portion, 25...Bottom wall (partition wall), 26... Recess, 31...first accommodating chamber, 31a, 31b...recess, 32...second accommodating chamber, 41...first shaft, 42...second shaft, 43...slide bearing, 44...rolling bearing, 45...bevel gear, 51...first gear, 52...second gear, 53...third gear, 55...crank, 60...operating mechanism, 61...cylinder, 62...piston, 63...striker, 64...intermediate element, 65...sleeve, 65a...bevel gear, 66...slider, 70, 71...sealing member, A, B...central axis

Claims

1. A work machine comprising: a motor; a first shaft; a second shaft; a first gear that receives the driving force of the motor and rotates around the central axis of the first shaft; an output section that rotates integrally with the first gear around the central axis of the first shaft; an operating mechanism that operates a tool bit in accordance with the rotation of the output section; a second gear that receives the driving force of the motor and rotates around the central axis of the second shaft; and a case section that defines a first and second storage chamber that are independent of each other, wherein the first gear is housed in the first storage chamber, the second shaft, the second gear, the output section and the operating mechanism are housed in the second storage chamber, and the first shaft is disposed astride the first storage chamber and the second storage chamber.

2. A work machine as described in claim 1, further comprising a third gear that rotates integrally with the first gear around the central axis of the first shaft, wherein the motor is disposed on one side of the first gear and the third gear is disposed on the other side of the first gear in the direction of the central axis of the first shaft.

3. A work machine according to claim 2, wherein the third gear is housed in the second housing.

4. A work machine according to claim 3, wherein the first gear and the third gear are fixed to the first shaft, and the second gear is fixed to the second shaft.

5. A work machine as described in claim 1, wherein the case portion has a partition wall separating the first storage chamber and the second storage chamber, the first shaft passes through the partition wall and straddles the first storage chamber and the second storage chamber, at least a portion of the second shaft is inserted into a recess formed in the second storage chamber by the partition wall, and a sealing member is provided between the first shaft and the partition wall, while no sealing member is provided between the second shaft and the partition wall.

6. The work machine according to claim 1, wherein the motor has an output shaft that meshes with the first gear, the first shaft and the second shaft are parallel to each other, and the output shaft is disposed between the first shaft and the second shaft.

7. A work machine as described in claim 1, wherein the actuating mechanism comprises a cylinder extending in a direction intersecting the direction of the central axis of the first shaft, and a piston capable of reciprocating within the cylinder in the longitudinal direction of the cylinder, the piston reciprocating linearly within the cylinder as the output part rotates.

8. A work machine as described in claim 7, further comprising a fourth gear that rotates integrally with the second gear around the central axis of the second shaft, the cylinder being rotatable with the central axis of the cylinder as a rotation axis, and the cylinder being provided with a fifth gear that meshes with the fourth gear and rotates integrally with the cylinder.

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