Electric cylinder and working machine

Abstract

The electric cylinder of the present application includes a motor as a driving source, an output shaft that rotates by driving of the motor, a first rotating body that is coupled to the output shaft and rotates by rotation of the output shaft, and a second rotating body that is adjacent to the first rotating body and rotates by rotation of the first rotating body, the first rotating body having a hollow portion that is open in a manner that allows lubricant to be received.

Description

Technical Field

[0001] This invention relates to electric cylinders and working machinery.

[0002] This invention claims priority based on Japanese Patent Application No. 2021-079546 filed on May 10, 2021, the contents of which are incorporated herein by reference. Background Technology

[0003] Patent Document 1 discloses an electric excavator as an example of a work machine. The electric excavator includes a vehicle body, a boom configured to rotate relative to the vehicle body, and an electric cylinder. The boom is driven by the electric cylinder.

[0004] Patent Document 2 discloses a structure for an electric cylinder comprising an inner cylinder for housing a threaded shaft extending vertically, and an outer cylinder for housing the inner cylinder in a telescopic manner. The inner cylinder is fixed to a nut that engages with the threaded shaft. A lubricant that flows through a flow hole into the outer cylinder is sealed in the lower half of the inner cylinder. An air chamber with an atmospheric communication hole formed at the upper end of the inner cylinder is formed in the upper half of the inner cylinder.

[0005] Patent document 3 discloses a structure comprising a main body elongated along its axial direction and a displacement mechanism disposed within the main body. The displacement mechanism includes a threaded shaft housed within the main body, a displacement nut screwed onto the threaded shaft, a piston mounted on the outer periphery of the displacement nut, and a piston rod connected to the piston. One end of the threaded shaft is connected to a connector. The connector is supported by a bearing for free rotation. The other end of the threaded shaft is connected to a cage. A support ring is provided on the outer periphery of the cage. The outer periphery of the support ring has multiple support portions formed in a concave-convex shape. The support portions slide in contact with the inner periphery of the piston rod, supporting the piston rod for free displacement along its axial direction. A stirring groove for guiding lubricant is formed on the outer periphery of the support ring.

[0006] Prior art literature

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2020-204172

[0009] Patent Document 2: Japanese Utility Model Publication No. 3-4962

[0010] Patent Document 3: Japanese Patent Application Publication No. 2009-275914 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] In the case of Patent Document 1, the boom rotates by being driven by an electric cylinder. In Patent Document 1, in order to prevent problems caused by the heat generated by the motor, the driving source of the electric cylinder, it is required that the heat from the motor be dissipated to the outside efficiently.

[0013] In the case of Patent Document 2, a lubricant is sealed inside the inner cylinder and the outer cylinder.

[0014] In the case of Patent Document 3, the lubricant is stirred by the stirring groove of the support ring.

[0015] In patent documents 2 and 3, a motor is provided that is arranged parallel to the threaded shaft. In order to prevent problems caused by the heat generated by the motor, there is room for improvement in the efficient dissipation of heat from the motor to the outside.

[0016] Therefore, the object of the present invention is to provide an electric cylinder and a working machine that can efficiently dissipate heat from a motor to the outside.

[0017] Methods for solving problems

[0018] An electric cylinder according to one aspect of the present invention comprises: a motor as a drive source; an output shaft that is rotated by the drive of the motor; a first rotating body connected to the output shaft and rotated by the rotation of the output shaft; and a second rotating body adjacent to the first rotating body and rotated by the rotation of the first rotating body, the first rotating body having a hollow portion that opens in a manner capable of accommodating lubricant.

[0019] Invention Effects

[0020] The above method enables heat from the motor to be dissipated to the outside efficiently. Attached Figure Description

[0021] Figure 1 This is a side view of the excavator in the implementation method.

[0022] Figure 2 This is a side view of the working device of the embodiment, and is shown through the inside of the boom and stick.

[0023] Figure 3 This is a perspective view of the boom according to the embodiment, and is shown through the interior of the boom.

[0024] Figure 4 This is a perspective view of the stick of the embodiment, and is shown through the interior of the stick.

[0025] Figure 5 This is a perspective view of the electric cylinder in the implementation method.

[0026] Figure 6This is a diagram showing the electric cylinder of the embodiment as viewed from one axial side.

[0027] Figure 7 This is a diagram showing the electric cylinder of the embodiment as viewed from the other side of the axial direction.

[0028] Figure 8 It includes Figure 7 A diagram of section VIII-VIII.

[0029] Figure 9 yes Figure 8 An enlarged view of section IX.

[0030] Figure 10 It includes Figure 9 A diagram of the XX section.

[0031] Figure 11 This is a perspective view of the first gear carrier in the embodiment.

[0032] Figure 12 This is a perspective view of the second gear carrier in the embodiment.

[0033] Figure 13 This is a diagram illustrating an example of the flow of lubricant in an embodiment. Detailed Implementation

[0034] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the embodiments, an excavator will be used as an example of a work machine (work vehicle).

[0035] <Excavator (operating machinery)>

[0036] like Figure 1 As shown, the excavator 1, as a working machine, includes a vehicle body 2 and a working device 3 connected to the vehicle body 2. Hereinafter, the forward direction, reverse direction, and vehicle width direction of the excavator 1 will be referred to as "vehicle front (one side of the vehicle's forward / reverse direction)," "vehicle rear (the other side of the vehicle's forward / reverse direction)," and "vehicle width direction." The vehicle width direction is also sometimes referred to as "left side (one side of the vehicle width direction)" or "right side (the other side of the vehicle width direction)." The right hand relative to the forward direction of the excavator 1 is referred to as the right side, and the left hand relative to the forward direction of the excavator 1 is referred to as the left side. The vertical direction, above, and below of the excavator 1 when it is positioned on a horizontal plane are simply referred to as "vertical direction," "above," and "below."

[0037] <Vehicle Body>

[0038] The vehicle body 2 has a lower driving body 5 capable of self-movement and an upper rotating body 6 that is freely rotated on the lower driving body 5.

[0039] The lower traveling body 5 has a pair of tracks 7 on the left and right sides. The lower traveling body 5 is equipped with an electric motor (not shown) to drive the tracks 7. The lower traveling body 5 moves by being driven by the electric motor through the tracks 7. It should be noted that the lower traveling body 5 may also be equipped with a hydraulic motor instead of an electric motor.

[0040] A bulldozer blade 8, extending along the width direction of the vehicle body 5, is provided at the front of the lower traveling body 5. The lower traveling body 5 is equipped with an electric actuator (not shown) that drives the bulldozer blade 8. The height position of the bulldozer blade 8 can be adjusted by driving the electric actuator.

[0041] The upper rotating body 6 is located on top of the lower traveling body 5. The upper rotating body 6 houses an electric motor for driving the lower traveling body 5, an electric cylinder motor for driving the working device 3, a battery, and an inverter (not shown) that serve as power sources for each motor. The upper rotating body 6 is capable of rotating relative to the lower traveling body 5 about an axis extending vertically.

[0042] A canopy 10 is provided on the upper rotating body 6. The canopy 10 has a driving space 11 capable of accommodating the driver. The canopy 10 includes a roof 12 forming the ceiling portion of the driving space 11, rear pillars 13 located on both sides of the rear of the roof 12 in the vehicle width direction and extending downward from the roof 12, and front pillars 14 located on both sides of the front of the roof 12 in the vehicle width direction and extending downward from the roof 12.

[0043] A bracket 15 supporting the boom 20 is provided at the front of the upper rotating body 6. For example... Figure 2 As shown, the bracket 15 has a first hole 15a and a second hole 15b that open along the vehicle width direction of the upper rotating body 6. The first hole 15a is located near the upper end of the bracket 15. The second hole 15b is located below and in front of the first hole 15a.

[0044] <Working Device>

[0045] like Figure 1As shown, the working device 3 is configured to move freely relative to the upper rotating body 6, bending and undulating as needed. The working device 3 includes a boom 20, a stick 30, a bucket 40 (working tool), and multiple (for example, three in this embodiment) electric cylinders 100A to 100C. The three electric cylinders 100A to 100C are: a first electric cylinder 100A for moving the boom 20, a second electric cylinder 100B for moving the stick 30, and a third electric cylinder 100C for moving the bucket 40. The base end of the boom 20 is rotatably connected to the upper rotating body 6. The front end of the boom 20 is rotatably connected to the base end of the stick 30. The front end of the stick 30 is rotatably connected to the bucket 40.

[0046] <Lump>

[0047] Boom 20 Figure 1 In its current position, when viewed from the vehicle width direction of the upper rotating body 6, the boom 20 extends upward from the bracket 15 and then curves forward and upward. Hereinafter, when viewed from the vehicle width direction of the upper rotating body 6, the direction in which the boom 20 extends is referred to as the "boom extension direction," and the direction orthogonal to the boom extension direction is referred to as the "boom plate width direction." In the boom extension direction, one end of the boom 20 (the end on the bracket 15 side) is designated as the "boom base end." In the boom extension direction, the other end of the boom 20 (the end opposite to the boom base end) is designated as the "boom front end." The dimension in the boom plate width direction gradually increases from the boom base end towards the center of the boom extension direction and then gradually decreases towards the boom front end.

[0048] like Figure 3 As shown, the boom 20 includes a pair of boom side plates 21 that are separately arranged in the vehicle width direction of the upper slewing body 6, a boom bottom plate 22 that extends in the vehicle width direction of the upper slewing body 6 and connects the pair of boom side plates 21 to each other, a boom base end side connecting plate 23 that is connected to the boom base end side of the boom bottom plate 22, a boom front end side connecting plate 24 that is connected to the boom front end side of the boom bottom plate 22, a boom separating member 25 that separates the space sandwiched between the pair of boom side plates 21 near the center in the boom extension direction, a boom base end support member 26 that supports the boom base end on the upper slewing body 6, and a stick support plate 27 that supports the stick 30.

[0049] The boom side plate 21 has a first cylinder base end side hole 21a and a second cylinder base end side hole 21b that open along the vehicle width direction of the upper slewing body 6. For example... Figure 2 As shown, when viewed from the vehicle width direction of the upper rotating body 6, the first cylinder base end side hole 21a is disposed on the lower side near the center in the boom extension direction, which is part of the first electric cylinder 100A. Figure 2The portion overlapping with the upper end of the upper cylinder 100B. When viewed from the vehicle width direction of the upper rotating body 6, the second cylinder base end side hole 21b is positioned on the upper side near the center in the boom extension direction, adjacent to a portion of the second electric cylinder 100B. Figure 2 The overlapping part near the lower end.

[0050] like Figure 3 As shown, the boom bottom plate 22 is disposed on the edge of the boom side plate 21 on the side opposite to the upper slewing body 6 in the boom plate width direction. The boom bottom plate 22 extends along the boom extension direction. The boom bottom plate 22 bends near the center in the boom extension direction toward the space between the first cylinder base end side hole 21a and the second cylinder base end side hole 21b.

[0051] The boom base end side connecting plate 23 extends along the vehicle width direction of the upper rotating body 6 on the boom base end side and connects a pair of boom side plates 21 to each other. The boom base end side connecting plate 23 extends towards the boom base end in such a way that it approaches the boom base end as it moves away from the connection with the boom bottom plate 22 in the boom plate width direction.

[0052] The boom front end side connecting plate 24 extends along the vehicle width direction of the upper slewing body 6 at the front end of the boom and connects a pair of boom side plates 21 to each other. The boom front end side connecting plate 24 extends towards the front end of the boom after extending in a manner that moves away from the connection portion with the boom bottom plate 22 in the boom plate width direction. The boom front end side connecting plate 24 has an opening 24a that opens along the boom extension direction at a position adjacent to one of the boom side plates 21.

[0053] The boom separator 25 extends near the center of the boom extension direction along the vehicle width direction of the upper slewing body 6 and connects a pair of boom side plates 21 to each other. The boom separator 25 extends along the width direction of the boom plates. The boom separator 25 is disposed between the first cylinder base end side hole 21a and the second cylinder base end side hole 21b. The boom separator 25 is separated from the boom bottom plate 22 in the width direction of the boom plates.

[0054] A boom base end support member 26 is disposed on the boom base end side. The boom base end support member 26 has a first through hole 26a opening in the vehicle width direction of the upper rotating body 6. A first pin 28 extending in the vehicle width direction of the upper rotating body 6 (see reference) is inserted into the first through hole 26a. Figure 2 By inserting a first pin 28 into the first through hole 26a of the boom base support member 26 and the second hole 15b of the bracket 15, the boom 20 is supported so that it can rotate about the central axis O1 of the first pin 28.

[0055] A boom support plate 27 is provided on the front end side of the boom. A boom support portion 16 is provided on the outer surface of the boom side plates 21 such that a pair of boom side plates 21 are clamped into it from the outside in the vehicle width direction of the upper rotating body 6. The boom support plate 27 protrudes outward relative to the boom side plates 21 in the boom extension direction. The boom support plate 27 has a second through hole 27a that opens in the vehicle width direction of the upper rotating body 6. The second through hole 27a is provided in the boom support plate 27 in a portion that protrudes outward relative to the boom side plates 21 in the boom extension direction. A second pin 29 (refer to...) extending in the vehicle width direction of the upper rotating body 6 is inserted into the second through hole 27a. Figure 2 ).

[0056] <Fighting Pole>

[0057] 30-meter pole Figure 1 In its posture, when viewed from the vehicle width direction of the upper rotating body 6, from a part of the second electric cylinder 100B ( Figure 1 The overlapping portion (near the upper end) extends downward and forward. Hereinafter, when viewed from the vehicle width direction of the upper rotating body 6, the direction in which the stick 30 extends is referred to as the "stick extension direction," and the direction orthogonal to the stick extension direction is referred to as the "stick width direction." In the stick extension direction, one end of the stick 30 (the end on the side of the second electric cylinder 100B) is referred to as the "stick base end." In the stick extension direction, the other end of the stick 30 (the end on the side opposite to the stick base end) is referred to as the "stick front end." The dimension in the stick width direction gradually increases from the stick base end towards the vicinity of the boom connection in the stick extension direction, and then gradually decreases towards the stick front end.

[0058] like Figure 4 As shown, the boom 30 has a pair of boom side plates 31 arranged separately in the vehicle width direction of the upper rotating body 6, a boom base plate 32 extending in the vehicle width direction of the upper rotating body 6 and connecting the pair of boom side plates 31 to each other, a boom side connecting plate 33 connected to the boom base plate 32, a boom separating member 34 that separates the space sandwiched between the pair of boom side plates 31 near the base end of the boom, a boom front end connecting member 35 connected to the front end of the boom, and a support bucket 40 (see reference). Figure 2 The bucket support member 36 and the first connecting rod support member 41 (see reference) Figure 2 ) One end of the connecting rod support member 37.

[0059] The boom side plate 31 has a second cylinder front end side hole 31a and a third cylinder base end side hole 31b, both opening in the vehicle width direction along the upper rotating body 6. For example... Figure 2 As shown, when viewed from the vehicle width direction of the upper rotating body 6, the front end side hole 31a of the second cylinder is located near the end of the boom base and is part of the second electric cylinder 100B. Figure 2 The portion overlapping with the upper end of the boom. When viewed from the vehicle width direction of the upper rotating body 6, the third cylinder base end side hole 31b is located on the opposite side of the portion overlapping with the front end of the boom in the boom plate width direction, at a point that overlaps with a portion of the third electric cylinder 100C. Figure 2 The overlapping part (near the upper end).

[0060] The bottom plate 32 of the boom is in Figure 2 In this posture, the stick side plate 31 is located at the edge of the upper rotating body 6 (boom 20 side) in the width direction of the stick plate. The stick bottom plate 32 extends along the stick extension direction. Figure 4 As shown, the boom base plate 32 extends across the space between the boom front connecting member 35 and the bucket support member 36 in the boom extension direction.

[0061] The boom side connecting plate 33 extends along the vehicle width direction of the upper rotating body 6 at the front end of the boom and connects a pair of boom side plates 31 to each other. The boom side connecting plate 33 extends towards the front end of the boom after extending in a manner that moves away from the connection with the boom bottom plate 32 in the boom plate width direction.

[0062] The stick separator 34 extends along the vehicle width direction of the upper slewing body 6 near the base end of the stick and connects a pair of stick side plates 31 to each other. The stick separator 34 is disposed between the front end side hole 31a of the second cylinder and the base end side hole 31b of the third cylinder. The stick separator 34 is disposed separately from the boom front end connecting member 35. When viewed from the vehicle width direction of the upper slewing body 6, the stick separator 34 extends from near the boom front end connecting member 35 toward the front end of the stick, then bends and extends in a manner that cuts across the space between the front end side hole 31a of the second cylinder and the base end side hole 31b of the third cylinder.

[0063] The boom front connecting member 35 is formed as a cylinder extending along the vehicle width direction of the upper rotating body 6. The boom front connecting member 35 has a boom connecting hole 35a that opens along the vehicle width direction of the upper rotating body 6. (As shown...) Figure 2 As shown, when viewed from the vehicle width direction of the upper rotating body 6, the boom connecting hole 35a overlaps with the second through hole 27a of the stick support plate 27. By inserting the second pin 29 into the second through hole 27a of the stick support plate 27 and the boom connecting hole 35a of the boom front connecting member 35, the stick 30 is supported so that it can rotate around the central axis O2 of the second pin 29 (see reference). Figure 4 Rotate.

[0064] like Figure 4As shown, a bucket support member 36 is disposed at the front end of the boom. The bucket support member 36 is formed as a cylinder extending in the vehicle width direction of the upper rotating body 6. The bucket support member 36 has a third through hole 36a opening in the vehicle width direction of the upper rotating body 6. A third pin 38 extending in the vehicle width direction of the upper rotating body 6 (see reference) is inserted into the third through hole 36a. Figure 2 ).

[0065] like Figure 4 As shown, the connecting rod support member 37 is disposed between the stick bottom plate 32 and the stick side connecting plate 33. The connecting rod support member 37 is disposed near the bucket support member 36. The connecting rod support member 37 is formed as a cylinder extending in the vehicle width direction of the upper rotating body 6. The connecting rod support member 37 protrudes outward in the vehicle width direction of the upper rotating body 6 relative to a pair of stick side plates 31. The connecting rod support member 37 has a first connecting rod connecting hole 37a that opens in the vehicle width direction of the upper rotating body 6.

[0066] <bucket>

[0067] Bucket 40 Figure 2 In this posture, it tilts from the front end of the stick towards the center of the boom extension direction. The bucket 40 has a bucket connection hole 40a that opens along the vehicle width direction of the upper rotating body 6 and a second link connection hole 40b.

[0068] Viewed from the vehicle width direction of the upper rotating body 6, the bucket connection hole 40a overlaps with the third through hole 36a of the bucket support member 36. By inserting a third pin 38 into both the third through hole 36a of the bucket support member 36 and the bucket connection hole 40a of the bucket 40, the bucket 40 is supported such that it can rotate around the central axis O3 of the third pin 38 (see reference). Figure 4 Rotate.

[0069] The second connecting rod connection hole 40b is in Figure 2 In this orientation, it is positioned downwards and backwards from the bucket connection hole 40a.

[0070] <The First Electric Cylinder>

[0071] like Figure 2 As shown, the first electric cylinder 100A is positioned closer to the boom base end than the boom separator 25. The first electric cylinder 100A includes a first cylinder body 103A configured to extend and retract along the boom extension direction, a first motor 101A as a drive source, and a first power transmission unit 102A that transmits the driving force of the first motor 101A to the first cylinder body 103A.

[0072] The first cylinder body 103A and the first motor 101A extend parallel to each other. The first end of the first cylinder body 103A is connected to a pin 51 that is inserted into a first hole 15a in the bracket 15. The first electric cylinder 100A is supported on the upper rotating body 6 via the bracket 15 in such a way that it can rotate about the central axis of the pin 51 that extends in the width direction of the upper rotating body 6.

[0073] The second end of the first cylinder body 103A is connected to a pin 52 that passes through the first cylinder base end side hole 21a of the boom 20. The first electric cylinder 100A is supported on the boom 20 in such a way that it can rotate about the central axis of the pin 52, which extends in the width direction of the upper rotating body 6.

[0074] The first motor 101A is disposed on the second end side of the first cylinder body 103A. The first motor 101A is positioned inside the first cylinder body 103A in the width direction of the boom plate. The first motor 101A uses a battery (not shown) installed in the upper rotating body 6 as a power source to move the first cylinder body 103A. Driven by the first motor 101A, the first cylinder body 103A extends and retracts, thereby causing the boom 20 to revolve around the central axis O1 of the first pin 28 (see reference 20) relative to the upper rotating body 6. Figure 3 Rotate.

[0075] A first wiring 61 extends from the first motor 101A. The first wiring 61 extends along the boom base end side connecting plate 23 and leads into the bracket 15. The first wiring 61 passes through the bracket 15 and connects to a battery (not shown).

[0076] <Second Electric Cylinder>

[0077] The second electric cylinder 100B is positioned closer to the front end of the boom than the boom separator 25. The second electric cylinder 100B includes a second cylinder body 103B configured to extend and retract along the boom extension direction, a second motor 101B as a drive source, and a second power transmission unit 102B that transmits the driving force of the second motor 101B to the second cylinder body 103B.

[0078] The second cylinder body 103B and the second motor 101B extend parallel to each other. The first end of the second cylinder body 103B is connected to a pin 53 that passes through the second cylinder base end side hole 21b of the boom 20. The second electric cylinder 100B is supported on the boom 20 in such a way that it can rotate relative to the boom 20 about the central axis of the pin 53 which extends in the width direction along the upper rotating body 6.

[0079] The second end of the second cylinder body 103B is connected to a pin 54 that passes through the second cylinder front end side hole 31a of the boom 30. The second electric cylinder 100B is supported on the boom 30 in such a way that it can rotate relative to the boom 30 about the central axis of the pin 54 which extends in the width direction of the upper rotating body 6.

[0080] The second motor 101B is disposed at the first end of the second cylinder body 103B. The second motor 101B is positioned inside the second cylinder body 103B in the width direction of the boom plate. The second motor 101B uses a battery (not shown) installed in the upper rotating body 6 as a power source to operate the second cylinder body 103B. Driven by the second motor 101B, the second cylinder body 103B extends and retracts, thereby causing the boom 30 to revolve around the central axis O2 of the second pin 29 (see reference 20) relative to the boom 20. Figure 3 Rotate.

[0081] A second wiring 62 extends from the second motor 101B. After extending toward the first motor 101A, the second wiring 62, together with the first wiring 61, extends along the boom base end side connecting plate 23 and leads into the bracket 15. The second wiring 62 passes through the bracket 15 and connects to a battery (not shown).

[0082] <Third Electric Cylinder>

[0083] The third electric cylinder 100C is positioned near the front end of the stick, relative to the stick separator 34. The third electric cylinder 100C includes a third cylinder body 103C capable of extending and retracting along the stick's extension direction, a third motor 101C serving as a drive source, and a third power transmission unit 102C that transmits the driving force of the third motor 101C to the third cylinder body 103C.

[0084] The third cylinder body 103C and the third motor 101C extend parallel to each other. The first end of the third cylinder body 103C is connected to a pin 55 that passes through the third cylinder base end side hole 31b of the boom 30. The third electric cylinder 100C is supported on the boom 30 in such a way that it can rotate relative to the boom 30 about the central axis of the pin 55 which extends in the width direction along the upper rotating body 6.

[0085] The second end of the third cylinder body 103C is connected to the first end of the first connecting rod member 41. The first end of the first connecting rod member 41 has a first connecting rod hole 41a that opens in the width direction of the upper rotating body 6. The second end of the third cylinder body 103C is connected to a pin 56 that passes through the first connecting rod hole 41a. The third electric cylinder 100C supports the first connecting rod member 41 in a manner that allows it to rotate relative to the first connecting rod member 41 about the central axis of the pin 56 that extends in the width direction of the upper rotating body 6.

[0086] The second end of the first link member 41 has a second link hole 41b that opens along the width direction of the upper rotating body 6. A pin 57 is inserted into the second link hole 41b and the first link connection hole 37a of the stick 30. The first link member 41 is supported on the stick 30 in such a way that it can rotate relative to the stick 30 about the central axis of the pin 57 that extends along the width direction of the upper rotating body 6.

[0087] The second end of the third cylinder body 103C is connected to the first end of the second connecting rod member 42. The first end of the second connecting rod member 42 has a third connecting rod hole 42a that opens along the width direction of the upper rotating body 6. The second end of the third cylinder body 103C is connected to a pin 56 that passes through the first connecting rod hole 41a and the third connecting rod hole 42a. The second connecting rod member 42 is configured to rotate about the central axis of the pin 56, which extends along the width direction of the upper rotating body 6, relative to the second end of the third cylinder body 103C and the first end of the first connecting rod member 41.

[0088] The second end of the second link member 42 has a fourth link hole 42b that extends through the width direction of the upper rotating body 6. A pin 58 is inserted into the fourth link hole 42b and the second link connection hole 40b of the bucket 40. The second link member 42 is configured to rotate relative to the bucket 40 about the central axis of the pin 58 that extends along the width direction of the upper rotating body 6.

[0089] The third motor 101C is located at the first end of the third cylinder body 103C. The third motor 101C is positioned inside the third cylinder body 103C in the width direction of the boom plate. The third motor 101C uses a battery (not shown) located in the upper rotating body 6 as a power source to operate the third cylinder body 103C. Driven by the third motor 101C, the third cylinder body 103C extends and retracts, thereby causing the bucket 40 to revolve around the central axis O3 of the third pin 38 relative to the boom 30 (see reference). Figure 4 Rotate.

[0090] A third wiring 63 extends from the third motor 101C. After extending toward the boom 20, the third wiring 63 passes through the opening 24a of the boom front end side connecting plate 24 (see reference). Figure 3 Subsequently, the third wiring 63 extends toward the first motor 101A and, together with the first wiring 61 and the second wiring 62, extends along the boom base end side connecting plate 23 and leads into the bracket 15. The third wiring 63 passes through the bracket 15 and connects to a battery (not shown).

[0091] <Electric cylinder>

[0092] like Figure 1 As shown, the first electric cylinder 100A, the second electric cylinder 100B, and the third electric cylinder 100C are shared electric cylinders 100. Figure 5 As shown, the electric cylinder 100 includes a motor 101, a power transmission unit 102, and a cylinder body 103.

[0093] Motor 101 is the drive source for electric cylinder 100. For example, motor 101 is a servo motor. Figure 8 As shown, the motor 101 and the cylinder body 103 extend parallel to each other. The motor 101 and the cylinder body 103 are arranged at intervals.

[0094] The electric cylinder 100 has an output shaft 105 that rotates under the drive of a motor 101. The output shaft 105 is coaxial with the central axis of the motor 101. The output shaft 105 protrudes axially outward from the axial end face 101f of the motor 101. In the figure, reference numeral C1 indicates the motor axis along the central axis of the motor 101.

[0095] The power transmission unit 102 transmits the driving force of the motor 101 to the piston 182. The power transmission unit 102 includes a planetary gear mechanism 110 that changes the speed (e.g., reduces the speed) of the driving force of the output shaft 105, and a transmission gear mechanism 120 that transmits the driving force changed by the planetary gear mechanism 110 to the piston 182.

[0096] Planetary gear mechanism

[0097] like Figure 9 As shown, the planetary gear mechanism 110 includes a sun gear 111 (first rotating body) connected to the output shaft 105, a plurality of planetary gears 112 (second rotating bodies) arranged adjacent to the sun gear 111, a gear carrier 114 and 115 supporting the central shaft 113 (hereinafter also referred to as "planetary shaft 113") of the plurality of planetary gears 112 for rotation, and a gear ring 116 surrounding the plurality of planetary gears 112. The planetary gear mechanism 110 is covered by a cylindrical housing 106 arranged adjacent to the axial end face 101f of the motor 101.

[0098] <Sun Wheel>

[0099] The sun gear 111 rotates due to the rotation of the output shaft 105. The sun gear 111 is formed as a cylindrical shape coaxial with the output shaft 105. The axial length of the sun gear 111 is longer than the length of the output shaft 105 protruding from the axial end face 101f of the motor 101. The axial base end of the sun gear 111 (the end on the motor 101 side) is separated from the axial end face 101f of the motor 101. The axial base end of the sun gear 111 is wider than the axial front end of the sun gear 111 (the end on the opposite side of the motor 101).

[0100] The sun gear 111 has a hollow portion 111a that opens in a manner capable of accommodating lubricant. The hollow portion 111a opens axially outward. The hollow portion 111a is a space enclosed by the axial front end of the output shaft 105 and the inner circumferential surface of the sun gear 111. The hollow portion 111a is disposed between the axial front end of the output shaft 105 and the axial front end of the sun gear 111.

[0101] <Planetary Wheel>

[0102] Planetary gear 112 rotates via the rotation of sun gear 111. For example... Figure 10 As shown, multiple planetary gears 112 (e.g., three in this embodiment) are arranged at equal intervals around the sun gear 111. External teeth on the outer periphery of the planetary gears 112 mesh with external teeth on the outer periphery of the sun gear 111. The planetary gears 112 rotate and revolve around the sun gear 111 by meshing with it. The planetary gears 112 are capable of rotating about a planetary shaft 113 that extends parallel to the output shaft 105.

[0103] <Gear Carrier>

[0104] like Figure 9 As shown, gear carriers 114 and 115 are coaxially mounted with the output shaft 105. Gear carriers 114 and 115 support the two axial ends of the planetary shaft 113. Gear carriers 114 and 115 extend from the outer periphery facing the sun gear 111 toward the planetary shaft 113 and have guide grooves 143a and 151a recessed in a manner that allows lubricant to flow.

[0105] Gear carriers 114 and 115 are a first gear carrier 114 disposed on the axial front end side of the output shaft 105, and a second gear carrier 115 disposed on the axial central side of the output shaft 105. For example... Figure 10 As shown, the first gear carrier 114 and the second gear carrier 115 are connected to each other by a plurality of bolts 145 (e.g., 6 in this embodiment).

[0106] <First Gear Carrier>

[0107] like Figure 11 As shown, the first gear carrier 114 has a first shaft hole 114a that is open to allow the planetary shaft 113 to pass through, and a bolt 145 (see reference) that is open to allow the bolt 145 to pass through. Figure 10 The first bolt hole 114b is an insertion-through type. The first gear carrier 114 has an annular first gear carrier base 140 and a cylindrical gear carrier front end cylinder 141 protruding axially outward from the first gear carrier base 140 (see reference). Figure 9The gear carrier includes a plurality of gear carrier wall portions 142 extending axially inward from the base 140 of the first gear carrier (in the direction opposite to the direction of the protrusion of the front end cylinder 141 of the gear carrier), and a first groove forming portion 143 disposed between two adjacent gear carrier wall portions 142 in the circumferential direction. The first gear carrier base 140, the front end cylinder 141 of the gear carrier, the gear carrier wall portions 142, and the first groove forming portion 143 are integrally formed from the same component.

[0108] like Figure 9 As shown, the outer diameter of the base 140 of the first gear carrier is larger than the outer diameter of the front end cylinder 141 of the gear carrier. The outer periphery of the base 140 of the first gear carrier is radially inward relative to the inner periphery of the housing 106.

[0109] like Figure 11 As shown, the first gear carrier base 140 has an annular groove 140a positioned opposite the axial front end of the output shaft 105, and a plurality of relay grooves 140b connected to the annular groove 140a. The annular groove 140a is formed in an annular shape along the inner circumference of the first gear carrier base 140. The relay grooves 140b bend radially outward from the outer periphery of the annular groove 140a.

[0110] Multiple (e.g., three in this embodiment) gear carrier wall portions 142 are arranged at equal intervals along the circumference of the first gear carrier base 140. The gear carrier wall portions 142 are positioned between the outer periphery of the annular groove 140a and the outer periphery of the first gear carrier base 140. When viewed axially, the gear carrier wall portions 142 have a shape that bulges circumferentially toward the first gear carrier base 140 as it moves radially outward. The side surfaces of the gear carrier wall portions 142 in the circumferential direction of the first gear carrier base 140 are curved in an arc shape along the shape of the first groove forming portion 143. Two first bolt holes 114b are provided in each gear carrier wall portion 142.

[0111] Multiple (e.g., three in this embodiment) first groove forming portions 143 are arranged at equal intervals along the circumference of the first gear carrier base 140. The first groove forming portions 143 are equally spaced from each other relative to the sides of two adjacent gear carrier wall portions 142 in the circumferential direction. The first groove forming portions 143 are provided at a position that overlaps with the planetary gear 112 when viewed from the axial direction.

[0112] The first groove forming portion 143 has a first guide groove 143a recessed in a manner that allows lubricant to flow through. When viewed axially, the first guide groove 143a is positioned on an imaginary line between the axis of the connecting gear carrier front end cylinder 141 and the axis of the first shaft hole 114a. For example... Figure 9 As shown, the first guide groove 143a extends from the axial front end facing the sun gear 111 toward the first shaft hole 114a. Figure 11As shown, the first guide groove 143a is disposed between the first shaft hole 114a and the relay groove 140b. The depth of the first guide groove 143a gradually increases from the first shaft hole 114a side toward the relay groove 140b.

[0113] The first groove forming portion 143 has a first receiving surface 143b that receives the axially outer end face of the planetary gear 112. When viewed axially, the first receiving surface 143b is formed in a C-shape with a partial opening in the first guide groove 143a. The first receiving surface 143b is configured to contact the axially outer end face of the planetary gear 112 at a portion other than the first guide groove 143a. The inner periphery of the first receiving surface 143b is radially outward compared to the outer periphery of the first shaft hole 114a.

[0114] <Second Gear Carrier>

[0115] like Figure 12 As shown, the second gear carrier 115 has a second shaft hole 115a that is open to allow the planetary shaft 113 to pass through, and a bolt 145 (see reference) that is open to allow the bolt 145 to pass through. Figure 10 The second bolt hole 115b is opened in a through-hole manner. The second gear carrier 115 has an annular second gear carrier base 150 and is provided in the axial direction with the first groove forming portion 143 (see reference). Figure 11 The second groove forming portion 151 is located opposite to the second gear carrier base portion 150 and the second groove forming portion 151 are integrally formed from the same component.

[0116] like Figure 9 As shown, the outer diameter of the second gear carrier base 150 is approximately the same as the outer diameter of the first gear carrier base 140. The outer periphery of the second gear carrier base 150 is radially inward relative to the inner periphery of the housing 106.

[0117] The second gear carrier base 150 has an opening 150a that allows the output shaft 105 to pass through. The second gear carrier base 150 also has a wall receiving portion 150b that receives the gear carrier wall portion 142 of the first gear carrier 114.

[0118] The wall support portion 150b is positioned to overlap with the gear carrier wall portion 142 when viewed axially. For example... Figure 12 As shown, the wall support portion 150b is provided with a plurality of portions (for example, three portions in this embodiment) relative to the gear carrier wall portion 142. Two second bolt holes 115b are provided in each wall support portion 150b.

[0119] Multiple (e.g., three in this embodiment) second groove forming portions 151 are arranged at equal intervals along the circumference of the second gear carrier base 150. The second groove forming portions 151 are positioned to overlap with the planet gear 112 when viewed from the axial direction.

[0120] The second groove forming portion 151 has a second guide groove 151a recessed in a manner that allows lubricant to flow through. When viewed axially, the second guide groove 151a is formed on an imaginary line connecting the center of the opening portion 150a and the axis of the second shaft hole 115a. For example... Figure 9 As shown, the second guide groove 151a extends from a position facing the outer periphery of the sun gear 111 toward the second shaft hole 115a. Figure 12 As shown, the second guide groove 151a is disposed between the second shaft hole 115a and the opening 150a. The depth of the second guide groove 151a gradually increases from the side of the second shaft hole 115a toward the opening 150a.

[0121] The second groove forming portion 151 has a second receiving surface 151b that receives the axial inner end face of the planetary gear 112. When viewed axially, the second receiving surface 151b is formed in a C-shape with a partial opening in the second guide groove 151a. The second receiving surface 151b is configured to contact the axial inner end face of the planetary gear 112 at a portion other than the second guide groove 151a. The inner periphery of the second receiving surface 151b is radially outward compared to the outer periphery of the second shaft hole 115a.

[0122] <Gear Ring>

[0123] like Figure 10 As shown, the internal teeth on the inner circumference of the gear ring 116 mesh with the external teeth on the outer circumference of each planetary gear 112. Multiple gear-side recesses 116a are provided on the outer circumferential surface of the gear ring 116 for the anti-rotation pin 117 to enter. The multiple (e.g., four in this embodiment) gear-side recesses 116a are circumferentially spaced apart.

[0124] Multiple housing-side recesses 106a are provided on the inner circumferential surface of the housing 106 for the anti-rotation pins 117 to enter. These multiple (e.g., four in this embodiment) housing-side recesses 106a are spaced equidistantly from each other in the circumferential direction. For example, by inserting the anti-rotation pins 117 into each recess 106a, 116a while aligning the circumferential positions of the gear-side recesses 116a and the housing-side recesses 106a, the rotation of the gear ring 116 can be stopped (restricting the circumferential movement of the gear ring 116 relative to the housing 106).

[0125] <spacer>

[0126] like Figure 9As shown, the electric cylinder 100 includes a spacer 118 disposed between the axial end face 101f of the motor 101 and the gear carriers 114 and 115. The spacer 118 has a through hole 118a that is spaced apart from the outer periphery (radial outer edge) of the sun gear 111 and opens axially along the motor 101. The gap of the through hole 118a is formed to allow lubricant to flow through. The spacer 118 has an inner recess 118b that opens axially inward at a position facing the axial end face 101f of the motor 101, and an outer recess 118c that opens axially outward to accommodate the second gear carrier 115.

[0127] The through hole 118a connects the radially central portions (the portion on the side of the sun gear 111) of the inner recess 118b and the outer recess 118c axially. The axially inner end of the through hole 118a is connected to the radially central portion of the inner recess 118b. The axially outer end of the through hole 118a is connected to the radially central portion of the outer recess 118c. The outer diameter of the inner recess 118b is larger than the outer diameter of the outer recess 118c. The outer periphery of the outer recess 118c is radially outward relative to the outer periphery of the second gear carrier 115.

[0128] The spacer 118 has a spacer side groove 118d that extends from the inner periphery of the outer recess 118c toward the axial inner end of the gear ring 116 and is recessed in such a way that lubricant can flow through it. The depth of the spacer side groove 118d gradually increases from the inner periphery of the outer recess 118c toward the axial inner end of the gear ring 116.

[0129] <Transmission Gear Mechanism>

[0130] like Figure 8 As shown, the transmission gear mechanism 120 includes a transmission gear 121 that transmits the rotational force of the gear carriers 114 and 115 to the piston 182, a transmission shaft 122 extending axially outward from a position facing the outer end of the sun gear 111, a freewheeling gear 123 disposed adjacent to the transmission gear 121, and a driven gear 124 disposed on the opposite side of the transmission gear 121, separated from the freewheeling gear 123. The transmission gear mechanism 120 is covered by a cover unit 160 disposed adjacent to the housing 106.

[0131] like Figure 9As shown, the transmission gear 121 and the output shaft 105 are coaxially mounted. The transmission gear 121 is formed as a cylindrical shape with an opening that allows the transmission shaft 122 to pass through. The transmission gear 121 includes a cylindrical gear body 121a with external teeth that mesh with the idler gear 123, an inner cylindrical body 121b protruding axially inward from the gear body 121a, and an outer cylindrical body 121c protruding axially outward from the gear body 121a. The gear body 121a, the inner cylindrical body 121b, and the outer cylindrical body 121c are integrally formed from the same component. The transmission gear 121 is supported by an inner bearing 130 provided on the outer periphery of the inner cylindrical body 121b and an outer bearing 131 provided on the outer periphery of the outer cylindrical body 121c, enabling it to rotate about the motor axis C1 relative to the cover unit 160.

[0132] The drive shaft 122 and the output shaft 105 are coaxially mounted. The front end shell 141 of the gear carrier is connected to one axial end of the drive shaft 122 via a spline. Internal teeth with tooth surfaces parallel to the axial direction of the front end shell 141 are provided on the inner circumference of the gear carrier. External teeth with tooth surfaces parallel to the axial direction of the drive shaft 122 are provided on the outer circumference of one axial end of the drive shaft 122, meshing with the internal teeth of the front end shell 141. A gap is formed between the external teeth on one axial end of the drive shaft 122 and the internal teeth of the front end shell 141, allowing lubricant to flow.

[0133] The gear body 121a of the transmission gear 121 is connected to the other axial end of the transmission shaft 122 via a spline. Internal teeth with tooth surfaces parallel to the axial direction of the transmission gear 121 are provided on the inner circumference of the gear body 121a. External teeth with tooth surfaces parallel to the axial direction of the transmission shaft 122 are provided on the outer circumference of the other axial end of the transmission shaft 122, meshing with the internal teeth of the gear body 121a. A gap is formed between the external teeth on the other axial end of the transmission shaft 122 and the internal teeth of the gear body 121a, allowing lubricant to flow.

[0134] The inner end of the inner cylinder 121b is connected to the front end of the gear carrier front cylinder 141 via an O-ring 132. A bearing 133 is provided between the inner circumference of the inner cylinder 121b and the outer circumference of the axial center portion of the drive shaft 122. For example, the bearing 133 is composed of a pair of semi-circular rings (so-called half-cut rings). A gap is formed between the axial center portion of the drive shaft 122 and the bearing 133 to allow lubricant to flow.

[0135] A cover member 135 is detachably mounted on the outer cylinder 121c. The cover member 135 has a supply hole 135a that opens to supply lubricant to the other axial end of the drive shaft 122 from the outside. The supply hole 135a is formed on the motor axis C1. A gap is formed between the outer axial end of the drive shaft 122 and the cover member 135 to allow lubricant to flow.

[0136] A grease nipple 136 is provided on the cover member 135, which can be opened and closed to allow lubricant to be supplied to the supply hole 135a from the outside. The grease nipple 136 is located on the motor axis C1. The grease nipple 136 extends axially outward relative to the cover member 135. The grease nipple 136 has an injection port (not shown) for lubricant leading to the supply hole 135a. The grease nipple 136 has a check valve in which a ball is pressed against the injection port by a spring from the inside. For example, by connecting a grease gun or the like to the grease nipple 136 and applying pressure, the grease nipple 136 can be opened, and lubricant can be supplied to the supply hole 135a through the injection port.

[0137] The idler gear 123 rotates due to the rotation of the transmission gear 121. The idler gear is rotatable about an idler shaft 123a that extends parallel to the transmission shaft 122. The idler gear 123 is formed as a cylindrical shape with an opening that allows the idler shaft 123a to pass through. A bearing 123b is provided between the inner circumference of the idler gear 123 and the outer circumference of the idler shaft 123a.

[0138] like Figure 8 As shown, driven gear 124 and idler gear 123 are arranged adjacent to each other. Driven gear 124 rotates by the rotation of idler gear 123. Driven gear 124 and cylinder shaft 180 housed inside cylinder body 103 are arranged coaxially. Reference numeral C2 in the figure indicates the cylinder axis along cylinder shaft 180.

[0139] The driven gear 124 is formed as a cylindrical opening that allows the first end of the cylinder shaft 180 to pass through. The driven gear 124 includes a cylindrical gear body 124a with external teeth that mesh with the idler gear 123, an inner cylindrical body 124b protruding axially inward from the gear body 124a, and an outer cylindrical body 124c protruding axially outward from the gear body 124a. The gear body 124a, the inner cylindrical body 124b, and the outer cylindrical body 124c are integrally formed from the same component.

[0140] Driven gear 124 is supported by an inner bearing 155 located on the outer periphery of the inner cylinder 124b and an outer bearing 156 located on the outer periphery of the outer cylinder 124c, so that it can rotate about cylinder axis C2 relative to cover unit 160.

[0141] In the accompanying drawings, reference numeral 137 indicates a cover member that is detachable from the outer cylinder 124c, and reference numeral 138 indicates a grease nipple provided on the cover member 137 and capable of being opened and closed to allow lubricant to be supplied from the outside to the supply hole of the cover member 137.

[0142] <Cover Unit>

[0143] The cover unit 160 includes a first cover 161 that covers the drive gear 121 from the axial outward, a second cover 162 that covers the driven gear 124 from the axial outward, and a third cover 163 that covers the drive gear 121, the idler gear 123 and the driven gear 124 from the radial outward of each gear.

[0144] like Figure 7 As shown, the first cover 161 has a rectangular shape when viewed from the axial direction. Figure 9 As shown, the first cover 161 has a first supply opening 161a that opens to supply lubricant to the other axial end of the drive shaft 122 from the outside. The first supply opening 161a is formed on the motor shaft C1. A gap is formed between the outer axial end of the drive gear 121 and the first cover 161 to allow lubricant to flow. A first cover member 165 is detachably mounted on the first cover 161 so that the first supply opening 161a can be opened and closed.

[0145] like Figure 8 As shown, the second cover 162 has a second supply opening 162a that opens to allow lubricant to be supplied from the outside to the first end side of the cylinder shaft 180. The second supply opening 162a is formed on the cylinder shaft C2. A gap is formed between the axially outer end of the driven gear 124 and the second cover 162 to allow lubricant to flow. A second cover member 166 is detachably mounted on the second cover 162 so that the second supply opening 162a can be opened and closed.

[0146] like Figure 7 As shown, the second cover 162 includes a vacant cover portion 162b, which, when viewed axially, is positioned to overlap with the vacant gear 123, and a driven cover portion 162c, which is positioned to overlap with the driven gear 124. The vacant cover portion 162b and the driven cover portion 162c are integrally formed from the same component. Figure 9 As shown, the idler housing 162b is fixed to the central shaft of the idler gear 123 by bolts 170.

[0147] like Figure 5 As shown, the third cover 163 includes a housing side cover portion 163a disposed between the housing 106 and the first cover 161, and a threaded side cover portion 163b disposed between the cylinder body 103 and the second cover 162.

[0148] like Figure 9 As shown, the housing side cover portion 163a is coaxially opened with respect to the motor axis C1. In the figures, reference numeral 167 indicates an inner spacer provided between the inner circumferential surface of the axially inner portion of the housing side cover portion 163a and the inner bearing 130, and reference numeral 168 indicates an outer spacer provided between the inner circumferential surface of the axially outer portion of the housing side cover portion 163a and the outer bearing 131.

[0149] like Figure 5 As shown, the first cover 161 is fastened to the housing 106 via a plurality of bolts 171 (e.g., four in this embodiment) through the housing side cover portion 163a. ​​The axial inner end of the housing side cover portion 163a is connected to the axial outer end of the housing 106 by the common fastening of the bolts 171.

[0150] The driven cover 162c is fixed to the threaded side cover 163b by a plurality of bolts 172 (e.g., 8 in this embodiment). The threaded side cover 163b is fixed to the cylinder body 103 by a plurality of bolts 173 (e.g., 4 in this embodiment).

[0151] <Cylinder Body>

[0152] like Figure 8 As shown, the cylinder body 103 includes a cylinder shaft 180, a nut 181 that is threaded to a threaded shaft 180a of the cylinder shaft 180, a piston 182 disposed on the outer periphery of the nut 181, a cylindrical piston rod 183 connected to the piston 182, a joint member 184 disposed at the front end of the piston rod 183, a cylindrical cylinder 185 that houses the piston rod 183, a retainer 186 disposed between the first end of the cylinder 185 and the threaded side cover portion 163b, and a rod cover 187 disposed at the second end of the cylinder 185.

[0153] A ball bearing (not shown) is sandwiched between a threaded shaft 180a and a nut 181. The threaded shaft 180a and the nut 181 constitute a ball screw that converts the rotary motion of the motor 101 into linear motion. The nut 181 is connected to a piston 182 by a plurality of bolts. The piston 182 is configured to move integrally with the nut 181 on the threaded shaft 180a. The piston rod 183 is configured to move integrally with the piston 182 along the cylinder axis C2.

[0154] like Figure 6 As shown, the joint member 184 protrudes outward relative to the outer periphery of the rod cover 187. For example... Figure 8 As shown, the connector member 184 has a connection hole 184a that opens in a direction orthogonal to the cylinder axis C2. A bearing 188 is provided between the inner circumferential surface of the cylinder 185 and the outer circumferential surface of the piston 182.

[0155] like Figure 5As shown, the cage 186 has a cylindrical cage body 190 and a trunnion portion 191 that protrudes radially outward from the cage body 190.

[0156] like Figure 8 As shown, the cage body 190 is coaxially opened with respect to the cylinder axis C2. Multiple bearings 189 are provided between the inner circumferential surface of the cage body 190 and the threaded shaft 180a. Figure 5 As shown, the trunnion portion 191 has a connecting hole 191a that opens in a direction orthogonal to the cylinder axis C2. The connecting hole 191a of the trunnion portion 191 opens parallel to the connecting hole 184a of the connector member 184.

[0157] <Action of the electric cylinder>

[0158] The following is an example of the operation of the electric cylinder 100.

[0159] like Figure 8 As shown, the driving force from motor 101 is reduced in speed by power transmission unit 102 and transmitted to cylinder shaft 180. Specifically, the driving force from motor 101 becomes a rotational force about motor axis C1, which is reduced in speed by output shaft 105, sun gear 111, multiple planetary gears 112, and gear carriers 114 and 115. The rotational force reduced in speed by gear carriers 114 and 115 is transmitted to transmission gear 121 via transmission shaft 122. The rotational force transmitted to transmission gear 121 is transmitted to cylinder shaft 180 via idler gear 123 and driven gear 124.

[0160] For example, when the motor 101 is rotating forward, the cylinder shaft 180 rotates in one direction about the cylinder axis C2. Due to this rotation of the cylinder shaft 180, the nut 181, which is threaded to the threaded shaft 180a of the cylinder shaft 180, moves in the direction of arrow M1 along the cylinder axis C2. This movement of the nut 181 in the direction of arrow M1 causes the piston 182, piston rod 183, and connector member 184 to move integrally in the direction of arrow M1. As a result, the cylinder body 103 elongates.

[0161] On the other hand, when the motor 101 is rotated in the reverse direction while the cylinder body 103 is extended, the cylinder shaft 180 rotates in the opposite direction around the cylinder axis C2. Due to this rotation of the cylinder shaft 180, the nut 181, which is threaded to the threaded shaft 180a of the cylinder shaft 180, moves along the cylinder axis C2 in the direction opposite to that of arrow M1. This movement of the nut 181 in the opposite direction to arrow M1 causes the piston 182, piston rod 183, and connector member 184 to move together in the opposite direction to arrow M1. As a result, the cylinder body 103 contracts.

[0162] In this way, the electric cylinder 100 is configured such that the cylinder body 103 extends and retracts by the forward and reverse rotation of the motor 101.

[0163] <Lubricant Flow>

[0164] The following is an example of lubricant flow.

[0165] like Figure 13 As shown, firstly, the first cover member 165 is removed from the cover unit 160, opening the first supply opening 161a. This exposes the grease nipple 136 through the first supply opening 161a. Next, the grease nipple 136 is opened by connecting it to, for example, a grease gun and applying pressure, and lubricant is supplied to the inner circumference (gap) of the transmission gear 121 through the supply hole 135a (in the direction of arrow L1 in the figure). This allows the lubricant to pass through the outer circumference (spline gap) of the transmission shaft 122 and enter the inner circumference (gap) of the gear carriers 114 and 115 (in the direction of arrow L2 in the figure). Afterward, the lubricant enters the hollow portion 111a of the sun gear 111 (in the direction of arrow L3 in the figure). This allows the lubricant to be retained in the hollow portion 111a.

[0166] When the output shaft 105 is rotated by the drive of the motor 101, the sun gear 111 rotates. As a result, the lubricant within the hollow portion 111a of the sun gear 111 flows radially outward from the axial front end of the sun gear 111 due to centrifugal force. A portion of the lubricant exiting from the axial front end of the sun gear 111 flows through the first guide groove 143a of the first gear carrier 114 in the direction of arrow L4, entering the inner circumferential side (clearance) and the side circumferential side (clearance) of the planet gear 112. Then, the lubricant enters the inner circumferential side (clearance) of the ring gear 116. Thus, the sun gear 111, planet gear 112, and ring gear 116 can be lubricated.

[0167] On the other hand, a portion of the lubricant exiting from the axial front end of the sun gear 111 flows through the outer periphery of the sun gear 111 in the direction of arrow L5 and enters the inner recess 118b of the spacer 118. As a result, the lubricant can be retained in the inner recess 118b of the spacer 118.

[0168] A portion of the lubricant flowing through the outer circumference of the sun gear 111 flows in the direction of arrow L6 via the second guide groove 151a of the second gear carrier 115, entering the inner circumference (clearance) and side circumference (clearance) of the planet gear 112. Then, the lubricant enters the inner circumference (clearance) of the ring gear 116. Thus, the sun gear 111, planet gear 112, and ring gear 116 are lubricated.

[0169] As described above, for example, by opening the grease nozzle 136 with a grease gun, lubricant is supplied through the supply hole 135a. Furthermore, by driving the motor 101, lubricant is trapped in the hollow portion 111a of the sun gear 111, the meshing portions of each gear, and the gap between the motor 101 and the spacer 118. This allows the heat generated by the motor 101 and the heat generated due to friction in each part to be released to the outside through the lubricated portion. Therefore, cooling of the motor 101 and the planetary gear mechanism 110 can be promoted.

[0170] <Effects>

[0171] As described above, the electric cylinder 100 of this embodiment includes a motor 101 as a drive source, an output shaft 105 that rotates under the drive of the motor 101, a sun gear 111 that is connected to the output shaft 105 and rotates under the rotation of the output shaft 105, and planet gears 112 that are adjacent to the sun gear 111 and rotate under the rotation of the sun gear 111. The sun gear 111 has a hollow portion 111a that opens in a manner that can accommodate lubricant.

[0172] According to this structure, lubricant can be retained in the hollow portion 111a of the sun gear 111. Furthermore, when the output shaft 105 is rotated by the drive of the motor 101, the sun gear 111 rotates. In this way, the lubricant in the hollow portion 111a of the sun gear 111 flows radially outward from the hollow portion 111a due to centrifugal force. Thus, a portion of the lubricant exiting from the hollow portion 111a of the sun gear 111 is transferred to the planet gear 112. Therefore, lubricant is trapped in the hollow portion 111a of the sun gear 111, the meshing portion of the sun gear 111 and the planet gear 112. Therefore, when heat generated by the motor 101 is transferred from the output shaft 105 to the sun gear 111, heat can be dissipated to the outside through the portion trapping the lubricant. Therefore, heat from the motor 101 can be dissipated to the outside efficiently.

[0173] In this embodiment, the output shaft 105 protrudes axially outward from the axial end face 101f of the motor 101. The first rotating body is formed as a cylindrical shape coaxial with the output shaft 105. The hollow portion 111a opens axially outward towards the sun gear 111.

[0174] According to this structure, a portion of the lubricant that exits from the hollow portion 111a of the sun gear 111 due to centrifugal force flows through the outer periphery of the sun gear 111 toward the axial end face 101f of the motor 101. Thus, lubricant is trapped in the portion facing the axial end face 101f of the motor 101. Therefore, heat generated by the motor 101 can be dissipated to the outside via the axial end face 101f of the motor 101 and the portion containing the lubricant. Therefore, heat from the motor 101 can be dissipated to the outside more efficiently.

[0175] In this embodiment, the electric cylinder 100 includes a planetary gear mechanism 110 that transmits the driving force of the motor 101 to the piston 182. The planetary gear mechanism 110 includes a sun gear 111, a plurality of planet gears 112, a gear carrier 114, 115 that supports the central shaft 113 of the plurality of planet gears 112 so that it can rotate, and a gear ring 116 surrounding the plurality of planet gears 112.

[0176] According to this structure, due to centrifugal force, a portion of the lubricant exiting from the hollow portion 111a of the sun gear 111 enters the inner circumference of each planet gear 112. Then, the lubricant enters the inner circumference of the ring gear 116. Thus, lubricant is trapped in the meshing portions of each gear constituting the planetary gear mechanism 110. Therefore, heat generated by the motor 101 can be dissipated to the outside through the portion of the planetary gear mechanism 110 containing lubricant. Therefore, cooling of the motor 101 and the planetary gear mechanism 110 can be promoted.

[0177] In this embodiment, the gear carriers 114 and 115 have guide grooves 143a and 151a that extend from the outer periphery of the sun gear 111 toward the central axis of the planet gear 112 and are recessed in a manner that allows lubricant to flow.

[0178] According to this structure, due to centrifugal force, a portion of the lubricant exiting from the hollow portion 111a of the sun gear 111 flows towards the central shaft 113 of the planetary gear 112 via the guide grooves 143a and 151a of the gear carriers 114 and 115. As a result, lubricant is trapped in the guide grooves 143a and 151a, and in the portion of the planetary gear 112 along the central shaft 113. Therefore, heat generated by the motor 101 can be dissipated to the outside via the portion trapping lubricant through the guide grooves 143a and 151a. Thus, cooling of the motor 101 and the planetary gear mechanism 110 can be further promoted.

[0179] In this embodiment, the electric cylinder 100 includes a spacer 118 disposed between the axial end face 101f of the motor 101 and the gear carriers 114 and 115. The spacer 118 has a through hole 118a that opens axially along the motor 101 at a gap from the outer periphery of the sun gear 111.

[0180] According to this structure, a portion of the lubricating part flowing through the outer periphery of the sun gear 111 enters the through hole 118a of the spacer 118 and flows toward the axial end face 101f of the motor 101. Thus, lubricant is trapped in the portion of the through hole 118a of the spacer 118 facing the axial end face 101f of the motor 101. Therefore, heat generated by the motor 101 can be dissipated to the outside through the portion of the spacer 118 containing lubricant from the axial end face 101f of the motor 101 through the through hole 118a. Therefore, heat from the motor 101 can be dissipated to the outside more efficiently.

[0181] In this embodiment, the electric cylinder 100 includes a transmission gear 121 that transmits the rotational force of the gear carriers 114 and 115 to the piston 182, and a transmission shaft 122 that extends axially outward from a position facing the outer end of the sun gear 111. The gear carrier 114 is engaged with one axial end of the transmission shaft 122 via a spline. The transmission gear 121 is engaged with the other axial end of the transmission shaft 122 via a spline.

[0182] According to this structure, lubricant is sandwiched in the portion facing the outer axial end of the sun gear 111, and in the portion along the drive shaft 122 (spline clearance), etc. Therefore, the heat generated by the motor 101 can be dissipated to the outside along the drive shaft 122 via the portion containing lubricant. Therefore, the cooling of the motor 101 and the planetary gear mechanism 110 can be further promoted.

[0183] In this embodiment, the electric cylinder 100 includes a cover member 135 having a supply hole 135a that is open to supply lubricant to the other axial end of the drive shaft 122 from the outside, and a grease nipple 136 provided on the cover member 135 and openable and closable to supply lubricant to the supply hole 135a from the outside.

[0184] According to this structure, after the electric cylinder 100 is assembled, the grease nipple 136 can be opened, and lubricant can be supplied from the outside to the meshing part of each gear and the hollow part 111a of the sun gear 111 through the supply hole 135a.

[0185] For example, the lubricant supply can be performed through the following steps. First, the grease nipple 136 is exposed to the outside. Next, the grease nipple 136 is opened by connecting it to, for example, a grease gun and applying pressure, and lubricant is supplied to the inner circumference (gap) of the transmission gear 121 through the supply hole 135a. In this way, the lubricant passes through the outer circumference (spline gap) of the transmission shaft 122 and enters the inner circumference (gap) of the gear carriers 114 and 115. Afterward, the lubricant enters the hollow portion 111a of the sun gear 111. Thus, lubricant is supplied from the outside to the meshing portion of each gear and the hollow portion 111a of the sun gear 111 through the supply hole 135a.

[0186] In this embodiment, the excavator 1 includes a vehicle body 2 and a working device 3 connected to the vehicle body 2. The working device 3 includes the electric cylinder 100 described above.

[0187] Therefore, an excavator 1 can be provided that can efficiently dissipate heat from the motor 101 to the outside.

[0188] In this embodiment, the working device 3 has a common electric cylinder 100 as a first electric cylinder 100A, a second electric cylinder 100B, and a third electric cylinder 100C.

[0189] Therefore, compared with the case where there are different electric cylinders as the first electric cylinder 100A, the second electric cylinder 100B and the third electric cylinder 100C, the number of parts can be reduced and the cost can be reduced.

[0190] <Other Implementation Methods>

[0191] In the above embodiments, an example of the hollow portion opening axially outward from the sun gear has been described, but the embodiments are not limited to this. For example, the hollow portion may also open radially outward from the sun gear. For example, the opening method of the hollow portion can be changed according to required specifications.

[0192] In the above embodiments, an example of an electric cylinder having a planetary gear mechanism that transmits the driving force of the motor to the piston has been described, but the embodiment is not limited to this. For example, an electric cylinder may not have a planetary gear mechanism. For example, an electric cylinder may also have a power transmission mechanism other than a planetary gear mechanism, such as a pulley mechanism or a rack and pinion mechanism. For example, the type of power transmission mechanism can be changed according to the required specifications.

[0193] In the above embodiments, an example has been described where the electric cylinder includes a sun gear that rotates via the rotation of the output shaft, planet gears adjacent to the sun gear and rotating via the rotation of the sun gear, and the sun gear has a hollow portion that opens in a manner that can accommodate lubricant. However, this is not a limitation. For example, the electric cylinder may also include a pulley that rotates via the rotation of the output shaft, and a belt that rotates via the rotation of the pulley, the pulley having a hollow portion that opens in a manner that can accommodate lubricant. For example, the electric cylinder may also include a pinion that rotates via the rotation of the output shaft, a belt that moves via the rotation of the pinion, and a gear that rotates via the movement of the belt, the pinion having a hollow portion that opens in a manner that can accommodate lubricant. For example, the type of rotating body with a hollow portion can be varied according to required specifications. For example, an electric cylinder may be provided with a motor as a drive source, an output shaft that rotates by the drive of the motor, a first rotating body that is connected to the output shaft and rotates by the rotation of the output shaft, and a second rotating body that is adjacent to the first rotating body and rotates by the rotation of the first rotating body, and the first rotating body has a hollow portion that opens in a manner that can accommodate lubricant.

[0194] In the above embodiments, an example has been described where the gear carrier has a guide groove that extends from the outer periphery of the sun gear toward the central axis of the planet gear and is recessed in a manner that allows lubricant to flow through, but this is not a limitation. For example, the guide groove may also extend axially along the outer periphery of the gear carrier. For example, the gear carrier may not have a guide groove. For example, the configuration of the gear carrier can be changed according to required specifications.

[0195] In the above embodiments, an example has been described where the electric cylinder includes a spacer disposed between the axial end face of the motor and the gear carrier, and the spacer has a through hole that opens axially along the motor and is spaced apart from the outer periphery of the sun gear. However, this is not a limitation. For example, the spacer may not be disposed between the axial end face of the motor and the gear carrier. For example, the gear carrier may face the axial end face of the motor, and the gear carrier may have a through hole that opens axially along the motor and is spaced apart from the outer periphery of the sun gear. For example, the arrangement of the spacer can be changed according to required specifications.

[0196] In the above embodiments, examples have been given, but the embodiments are not limited thereto: the electric cylinder includes a transmission gear that transmits the rotational force of the gear carrier to the piston, and a transmission shaft extending axially outward from a position facing the outer axial end of the sun gear. The gear carrier is engaged with one axial end of the transmission shaft via a spline, and the transmission gear is engaged with the other axial end of the transmission shaft via a spline. For example, the gear carrier may also be engaged with one axial end of the transmission shaft by means other than press-fitting splines. For example, the transmission gear may also be engaged with the other axial end of the transmission shaft by means other than press-fitting splines. For example, the engagement method of the transmission shaft can be changed according to required specifications.

[0197] In the above embodiments, an example has been described where the electric cylinder includes a cover member with a supply hole that opens to allow lubricant to be supplied from the outside to the axial end of the drive shaft, and a grease nipple provided on the cover member and capable of being opened and closed to allow lubricant to be supplied from the outside to the supply hole. However, this is not a limitation. For example, the electric cylinder may not have a cover member or a grease nipple. For example, the axial end of the drive shaft may be covered by a drive gear. For example, the supply hole may be provided on a component other than the cover member, such as the drive gear. For example, the grease nipple may be provided on a component other than the cover member, such as the drive gear. For example, the arrangement of the supply hole and the arrangement of the grease nipple may be changed according to required specifications.

[0198] In the above embodiments, examples of the working device having a common electric cylinder as the first electric cylinder, the second electric cylinder, and the third electric cylinder have been described, but the invention is not limited to this. For example, the working device may also have different electric cylinders as the first electric cylinder, the second electric cylinder, and the third electric cylinder. For example, the arrangement of the electric cylinders can be changed according to required specifications.

[0199] In the above embodiments, an excavator was described as an example of a work machine (work vehicle), but the invention is not limited thereto. For example, the invention can also be applied to other work vehicles such as dump trucks, bulldozers, and wheel loaders.

[0200] The embodiments of the present invention have been described above, but the present invention is not limited thereto. Structural additions, omissions, substitutions, and other changes can be made without departing from the spirit of the present invention, and the above embodiments can also be appropriately combined.

[0201] Explanation of reference numerals in the attached figures:

[0202] 1…Excavator (operating machinery); 2…Vehicle body; 3…Working device; 100…Electric cylinder; 100A…First electric cylinder; 100B…Second electric cylinder; 100C…Third electric cylinder; 101…Motor; 101f…Axial end face of the motor; 101A…First motor; 101B…Second motor; 101C…Third motor; 105…Output shaft; 110…Planetary gear mechanism; 111…Sun gear (first rotating body) ; 111a… Hollow section; 112… Planetary gear (second rotating body); 113… Planetary shaft (central shaft of planetary gear); 114… First gear carrier (gear carrier); 115… Second gear carrier (gear carrier); 116… Gear ring; 118… Spacer; 118a… Through hole; 121… Transmission gear; 122… Transmission shaft; 135… Cover component; 135a… Supply hole; 136… Grease nipple; 143a… First guide groove (guide groove); 151a… Second guide groove (guide groove); 182… Piston.

Claims

1. An electric cylinder, wherein, The electric cylinder has the following features: The motor serves as the driving source; The output shaft rotates as driven by the motor. A first rotating body is connected to the output shaft and rotates by rotating the output shaft; as well as The second rotating body is adjacent to the first rotating body and rotates by means of the rotation of the first rotating body. The first rotating body has a hollow portion that opens in a manner capable of accommodating lubricant. As the first rotating body rotates, the lubricant inside the hollow portion flows radially outward toward the first rotating body.

2. The electric cylinder according to claim 1, wherein, The output shaft protrudes axially outward from the axial end face of the motor. The first rotating body is formed as a cylinder coaxial with the output shaft. The hollow portion opens outward along the axis of the first rotating body.

3. The electric cylinder according to claim 2, wherein, The electric cylinder also includes a planetary gear mechanism that transmits the driving force of the motor to the piston. The planetary gear mechanism has the following features: The sun gear, which is the first rotating body; Multiple planetary gears serving as the second rotating body; A gear carrier that supports the central axis of the plurality of planetary gears for rotation; and A gear ring that surrounds the plurality of planetary gears.

4. The electric cylinder according to claim 3, wherein, The gear carrier has guide grooves that extend from the outer periphery of the sun gear toward the central axis of the planet gear and are recessed in a manner that allows the lubricant to flow through.

5. The electric cylinder according to claim 3 or 4, wherein, The electric cylinder also includes a spacer disposed between the axial end face of the motor and the gear carrier. The spacer has a through hole that opens axially along the motor, spaced apart from the outer periphery of the sun gear.

6. The electric cylinder according to claim 3 or 4, wherein, The electric cylinder also features: A transmission gear that transmits the rotational force of the gear carrier to the piston; and A drive shaft extends axially outward from a position facing the outermost end of the sun gear. The gear carrier is connected to one axial end of the drive shaft via a spline. The transmission gear is connected to the other axial end of the transmission shaft via a spline.

7. The electric cylinder according to claim 6, wherein, The electric cylinder also features: The cover member has a supply hole that opens in such a way that the lubricant can be supplied from the outside to the other axial end side of the drive shaft; as well as A grease nipple is disposed on the cover member and is openable and closable to allow the lubricant to be supplied to the supply hole from the outside.

8. A type of operating machinery, wherein, The operating machinery includes: The vehicle body; and The working device is connected to the vehicle body. The working device includes the electric cylinder as described in any one of claims 1 to 4.

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