Drive transmission device and construction machine and assembly method of construction machine

Abstract

The present application relates to a drive transmission device, a construction machine, and an assembling method of a construction machine. The drive transmission device includes a first member and a second member, a drive source, two bracket portions, a shaft portion, a reduction portion having an output portion, and a housing portion. The first member and the second member are connected to each other so as to be rotatable about a rotation axis. The drive source generates a rotational force that drives the first member and the second member. The two bracket portions are provided to the second member and are disposed in opposition to each other in a direction of the rotation axis. The shaft portion is connected to the first member and is positioned between the bracket portions in the direction of the rotation axis. The output portion is mounted to the shaft portion and to an opposite surface of the first bracket portion that is positioned on an inner side in the direction of the rotation axis. The housing portion is connected to the shaft portion so as to be rotatable about the rotation axis and is mounted to an opposite surface of the second bracket portion that is positioned on an inner side in the direction of the rotation axis.

Description

Technical Field

[0001] This invention relates to drive transmission devices, construction machinery, and methods for assembling construction machinery. In particular, it relates to techniques suitable for the construction and sealing mechanisms of joint actuators for excavators. Background Technology

[0002] For example, construction machinery such as hydraulic excavators includes: a traveling body that moves independently; and a slewing body that is rotatably mounted on the traveling body. The slewing body has an operator's cab for the operator to sit in. One end of the actuator is rotatably (swingably) connected to the slewing body.

[0003] Examples of working parts include: a boom; a stick, which is rotatably connected to the boom; and a bucket, which is rotatably connected to the stick. One end of the stick is rotatably connected to the other end of the boom (located on the side opposite to the boom). The bucket is rotatably connected to the other end of the stick (located on the side opposite to the boom).

[0004] Hydraulic actuators with direct-acting mechanisms are commonly used as drive transmission devices in the connection points between the slewing body and the boom, the boom and the stick, and the stick and the bucket. By driving the hydraulic actuators, the slewing body can rotate relative to the traveling body, and the boom, stick, and bucket can swing.

[0005] However, in recent years, there has been a desire for electrification due to considerations such as simplifying the construction of construction machinery. Therefore, solutions using electric actuators as drive transmission devices have been proposed. For example, Patent Document 1 discloses a technology that uses an electric cylinder with a direct-drive mechanism that incorporates a ball screw-type speed reducer to replace a hydraulic actuator.

[0006] Furthermore, it is known that with the advent of electrification, a rotary actuator has been used as a speed reducer (speed reduction unit).

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 63-300131 Summary of the Invention

[0010] The problem the invention aims to solve

[0011] Construction machinery can easily place significant loads on its connections depending on the operating environment. Therefore, actuators, especially transmission components, need to have sufficient mechanical strength to withstand these loads.

[0012] As for electric actuators, one might consider using, for example, linear actuators or rotary actuators. However, linear actuators do not operate when the thrust is not perpendicular to the input rod, resulting in poor efficiency. In contrast, rotary actuators operate regardless of the input rod's orientation, thus offering good efficiency.

[0013] However, the use of rotary actuators easily generates radial and torque loads. Therefore, when a rotary actuator is installed (especially when the reducer is only installed on one side), the radial and torque loads shift. Consequently, to achieve the required strength, there is a problem of increasing the size of the actuator. Even assuming that the increase in actuator size is suppressed, there is a possibility of a shortened reducer lifespan.

[0014] The present invention provides a drive transmission device and construction machinery capable of suppressing large-scale loads and loads such as radial loads and torque loads, as well as an assembly method for the construction machinery.

[0015] Solution for solving the problem

[0016] (1) A drive transmission device according to one embodiment of the present invention comprises: a shaft portion; a reduction gear portion mounted on the shaft portion; and a housing portion connected to the shaft portion in a manner rotatable relative to the shaft portion about a rotation axis of the output of the reduction gear portion, and the housing portion being mounted on a first bracket portion. The reduction gear portion comprises: an input portion for inputting a rotational driving force from a drive source; and an output portion mounted on a second bracket portion, the second bracket portion being integrated with the first bracket portion, and the second bracket portion and the first bracket portion being separately arranged opposite each other along the rotation axis direction.

[0017] With this configuration, only one reduction gear is needed instead of two, thus preventing the structure from becoming too large. Furthermore, by utilizing the housing coaxially arranged with the reduction gear and its output axis, the support can be rotated while suppressing loads such as radial and torque loads.

[0018] (2) Alternatively, the shaft and the housing can move relative to each other in the direction of the rotation axis.

[0019] (3) Alternatively, the outer casing may be formed in an annular shape and fitted into the outer periphery of the shaft. Alternatively, a gap may be formed between the outer periphery of the outer casing and the outer periphery of the shaft in the direction of the rotation axis.

[0020] (4) Alternatively, a labyrinth seal may be provided between the outer periphery of the outer casing and the outer periphery of the shaft.

[0021] (5) Alternatively, at least one of the first and second bracket portions may have an assembly position limiting portion with a predetermined height toward the inside along the rotation axis provided on its opposing surface. Alternatively, the separation distance of the gap may be greater than the height of the assembly position limiting portion in the direction along the rotation axis.

[0022] (6) Alternatively, a bearing may be provided between the outer casing and the shaft. Alternatively, the bearing may be interference-fitted with either the outer casing or the shaft, and clearance-fitted with the other.

[0023] (7) Alternatively, the radial dimension of the connection position between the outer shell portion and the first support portion about the axis of rotation is equal to the radial dimension of the connection position between the deceleration portion and the second support portion about the axis of rotation.

[0024] (8) A construction machine according to a technical solution of the present invention comprises: a shaft; a reduction gear mounted on the shaft; and a housing connected to the shaft in a manner rotatable about a rotation axis relative to the shaft, and the housing is mounted on a first support. The reduction gear has: an input portion that receives a rotational driving force from a drive source; and an output portion mounted on a second support. The second support portion is integrated with the first support portion, and the second support portion and the first support portion are separately arranged opposite to each other along the rotation axis. The output portion is mounted on the second support portion and rotates about the rotation axis. The shaft and the housing are movable relative to each other in the rotation axis direction. The housing is formed in an annular shape and fits around the shaft. A gap is formed between the outer periphery of the housing and the outer periphery of the shaft in the rotation axis direction. A labyrinth seal is provided between the outer periphery of the housing and the outer periphery of the shaft. At least one of the first and second support portions has an assembly position limiting portion with a predetermined height facing inward along the rotation axis on its opposing surface. The separation distance of the gap along the rotation axis is greater than the height of the assembly position limiting portion. A bearing is provided between the housing portion and the shaft portion. The bearing has an interference fit with either the housing portion or the shaft portion, and a clearance fit with the other. The radial dimension of the connection position between the housing portion and the first support portion about the rotation axis is equal to the radial dimension of the connection position between the deceleration portion and the second support portion about the rotation axis.

[0025] With this configuration, the reduction section and the housing section can be arranged separately on the coaxial axis of rotation as structures corresponding to the bearings. This allows for a structure that can evenly support external loads, and enables the reduction of the size of the drive transmission device with a simple construction. Furthermore, it can suppress the deviation of external loads such as radial loads and torque loads acting on the drive transmission device, and can extend the service life of the structural components of the drive transmission device.

[0026] (9) An assembly method for construction machinery according to a technical solution of the present invention comprises: a gap shortening step, wherein the outer shell portion and the shaft portion are brought closer together in the direction of the rotation axis to shorten the gap formed between the outer shell portion and the shaft portion; an insertion step, wherein after the gap shortening step, the shaft portion is inserted between the support portions from a direction intersecting the rotation axis; a gap lengthening step, wherein after the insertion step, the outer shell portion and the shaft portion are moved away from each other in the direction of the rotation axis to lengthen the gap formed between the outer shell portion and the shaft portion; an installation step, wherein the output portion of the deceleration unit is installed on the opposing surface located inside the rotation axis direction in the second support portion; and an installation step, wherein the outer shell portion is installed on the opposing surface located inside the rotation axis direction in the first support portion.

[0027] The effects of the invention

[0028] According to the present invention, it is possible to suppress the enlargement of the load and to suppress the offset of loads such as radial loads and torque loads. Attached Figure Description

[0029] Figure 1 This is a schematic structural diagram of an excavator, which is the first embodiment of the construction machinery of the present invention, viewed from the side.

[0030] Figure 2 This is a schematic structural diagram showing the connection between the boom and the bucket in the first embodiment of the drive transmission device and construction machinery of the present invention.

[0031] Figure 3 This is a schematic structural diagram illustrating the first embodiment of the drive transmission device of the present invention.

[0032] Figure 4 This is a cross-sectional view showing the deceleration section in the first embodiment of the drive transmission device of the present invention.

[0033] Figure 5 This is a schematic structural diagram showing the dimensions and assembly process of the drive transmission device of the present invention in the first embodiment.

[0034] Figure 6This is a schematic structural diagram illustrating the assembly process in the first embodiment of the drive transmission device of the present invention.

[0035] Figure 7 This is a schematic structural diagram illustrating the assembly process in the first embodiment of the drive transmission device of the present invention.

[0036] Figure 8 This is a schematic structural diagram showing the dimensions and assembly process of the drive transmission device in the second embodiment of the present invention.

[0037] Figure 9 This is a schematic structural diagram showing the dimensions and assembly process of the drive transmission device in the third embodiment of the present invention.

[0038] Figure 10 This is an enlarged structural diagram showing the fourth embodiment of the drive transmission device of the present invention.

[0039] Explanation of reference numerals in the attached figures

[0040] 1. Drive transmission device; 2. Shaft; 4. Reduction unit; 6. Housing; 8. Bearing; 11. Housing (fixed part); 14. Gear frame (output part); 18. Reduction input unit (input part); 100. Excavator (construction machinery); 101. Traveling body (main body); 103. Rotating body (main body); 104. Actuating part; 108. Boom; 109. Stick (first component); 110. Bucket (second component); 111, 112. Mounting bracket (support part); 120. Electric motor (drive source); C2. Rotation axis (second rotation axis). Detailed Implementation

[0041] (First Embodiment)

[0042] The first embodiment of the present invention will be described with reference to the accompanying drawings.

[0043] <Excavator>

[0044] Figure 1 This is a schematic diagram of the excavator 100, which is the construction machinery of this embodiment, viewed from the side.

[0045] Furthermore, in the following explanation, in Figure 1 In the state shown for the excavator 100, the direction facing forward when the operator of the excavator 100 is seated in the driver's seat is simply referred to as "forward." The side opposite to "forward" in the horizontal direction is referred to as "rear." Furthermore, the vertical direction when the excavator 100 is positioned on the road surface is simply referred to as "vertical direction." Moreover, the direction orthogonal to the forward / backward and vertical directions is referred to as the vehicle width direction. Therefore, in Figure 1 The middle section indicates the state of the excavator 100 as viewed from the width direction.

[0046] like Figure 1 As shown, the excavator (an example of construction machinery) 100 of this embodiment includes: a traveling body 101 that moves on its own; a rotating body 103 that is disposed on the upper part of the traveling body 101 by means of a rotating mechanism 102 and rotates relative to the traveling body 101; and an action part 104 disposed on the rotating body 103.

[0047] The traveling body 101 and the slewing mechanism 102 are driven, for example, by an electric motor with a reducer (not shown). The traveling body 101 has, for example, two tracks 105 arranged in the vehicle width direction. However, it is not limited to this case; for example, wheels or the like may be used instead of tracks 105.

[0048] An operator's cab 106 is provided on the front side of the slewing body 103. The operator's cab 106 is positioned to the side biased towards the vehicle width direction. The operator operates the excavator 100 from inside the operator's cab 106. Furthermore, a support portion (not shown) is provided on the front side of the slewing body 103 adjacent to the operator's cab 106. The support portion is positioned approximately at the center in the vehicle width direction. An operating part 104 is mounted on the support portion.

[0049] The operating unit 104 includes a boom 108 and a stick 109 that are relatively long in the longitudinal direction, and a bucket (an example of an accessory) 110. The boom 108, stick 109, and bucket 110 are all connected to rotate freely by means of a drive transmission device 1.

[0050] Specifically, one end of the boom 108 along its length is rotatably connected to the support portion of the rotating body 103 via a drive transmission device 1. However, in Figure 1 The diagram omits one end of the boom 108 and the drive transmission device 1 disposed at that end. The other end 108a of the boom 108 along its length is rotatably connected to one end 109a of the stick 109 along its length via the drive transmission device 1. The other end 109b of the stick 109 is rotatably connected to the bucket 110 via the drive transmission device 1. Furthermore, the bucket 110 is mounted to the stick 109 at its center in the vehicle width direction.

[0051] The drive transmission devices 1 installed at each connection point are all of the same structure. Therefore, in the following description, only the drive transmission device 1 that connects to the bucket 110 at the other end 109b of the boom 109 will be described, and the description of other drive transmission devices 1 will be omitted.

[0052] Figure 2 This is a schematic structural diagram showing the connection between the boom 109 and the bucket 110. Figure 2In order to make the explanation easy to understand, double-dotted lines are used to represent the boom 109 and the bucket 110. Figure 3 This is an enlarged cross-sectional view of the drive transmission device 1. Figure 3 In order to make the explanation easy to understand, double-dotted lines are used to represent the boom 109 and the bucket 110.

[0053] like Figure 2 As shown, a motor (the drive source of the claim, an example of a motor) 120 is built into the boom 109. Thus, the rotational force of the motor 120 can be transmitted to the bucket 110 by means of the drive transmission device 1.

[0054] Furthermore, the boom 109 is an example of the first component of claim 1. The bucket 110 is an example of the second component of claim 2.

[0055] Motor 120 is, for example, an electric motor driven by electricity supplied from an external power source (battery) provided in the rotating body 103. As motor 120, various types of motors driven by electricity, such as brushed motors and brushless motors, can be used.

[0056] The motor 120 has a motor shaft 120a that rotates about a first rotation axis C1. The motor shaft 120a is arranged from the motor 120 side toward the bucket 110 side. Furthermore, the first rotation axis C1 is aligned with the length direction of the stick 109.

[0057] Motor 120 can also be a hydraulic motor. In this case, the hydraulic motor is driven, for example, by hydraulic pressure supplied to the pressure fluid supply unit provided in the rotating body 103.

[0058] <Drive Transmission Device>

[0059] like Figure 2 , Figure 3 As shown, the drive transmission device 1 is disposed on a second rotation axis (an example of the rotation axis of the claim) C2 of the bucket 110 relative to the stick 109. On the second rotation axis C2, mounting brackets (bracket portions) 111 and 112 of the bucket 110 are disposed on both sides clamping the drive transmission device 1. The mounting brackets (second bracket portion) 111 and (first bracket portion) 112 are disposed opposite to each other in a manner that separates them in the direction along the second rotation axis C2. The mounting brackets 111 and 112 are fixed to the drive transmission device 1, thereby allowing the bucket 110 to rotate relative to the stick 109 about the second rotation axis C2.

[0060] Furthermore, mounting bracket 111 and mounting bracket 112 are integrally combined with each other by means of drive transmission device 1. Thus, mounting bracket 111 and mounting bracket 112 are integrated.

[0061] like Figure 2 , Figure 3 As shown, the drive transmission device 1 includes a shaft 2, a reduction gear 4, a housing 6, and a bearing 8.

[0062] The shaft 2 is fixed to the other end 109b of the stick 109. The shaft 2 is located between the mounting bracket 111 and the mounting bracket 112 along the second rotation axis C2. The deceleration unit 4 is positioned close to the mounting bracket 111 and is connected to the mounting bracket 111.

[0063] The housing portion 6 is positioned near the mounting bracket 112 and is connected to the mounting bracket 112. The housing portion 6 is connected to the shaft portion 2 in a manner that allows it to rotate freely relative to the shaft portion 2 about a second axis of rotation C2. Specifically, the housing portion 6 is connected to the outer periphery of the shaft portion 2 by means of a bearing 8.

[0064] In the following description, the direction parallel to the second axis of rotation C2 is referred to as the axial direction, and the direction about the second axis of rotation C2 is referred to as the circumferential direction. Furthermore, the direction orthogonal to the axial and circumferential directions is sometimes referred to as the radial direction.

[0065] <Shaft>

[0066] The shaft portion 2 has: a fixing portion 2a, which is fixed to the other end 109b of the stick 109; and a rotation transmission portion 2b, which is disposed at a position further away from the stick 109 than the fixing portion 2a along the first rotation axis C1.

[0067] The rotation transmission section 2b extends along the second rotation axis C2. The rotation transmission section 2b has a generally cylindrical outer surface centered on the second rotation axis C2, at least along the bucket 110.

[0068] The rotation transmission unit 2b has an internal space 2c that opens on the side of the mounting bracket 111. A deceleration unit 4 is installed in the opening of the internal space 2c. Furthermore, the axis of the opening of the internal space 2c coincides with the second rotation axis C2. The installation of the deceleration unit 4 seals the opening of the internal space 2c. In the rotation transmission unit 2b, a cylindrical outer casing shaft portion 2d is formed near the mounting bracket 112. The outer casing shaft portion 2d extends along the second rotation axis C2. Furthermore, the axis of the outer casing shaft portion 2d coincides with the second rotation axis C2. An annular outer casing portion 6 is installed on the outer periphery of the outer casing shaft portion 2d. The structure of the periphery of the outer casing shaft portion 2d will be discussed subsequently along with the description of the outer casing portion 6.

[0069] In this embodiment, the housing shaft portion 2d is described as a solid cylindrical shaft. However, it is not limited to this case. For example, the housing shaft portion 2d may be configured as a cylindrical shape with an internal space to house the motor 120. In this case, a structure with a transmission shaft along the second rotation axis C2 can be provided instead of the transmission shaft 121 described later.

[0070] The reduction gear 4 is connected to the motor shaft 120a via a transmission shaft 121. The reduction gear 4 transmits the drive rotation from the motor 120 via a first bevel gear 71 and a second bevel gear 72. The first bevel gear 71 is formed on the transmission shaft 121 and rotates together with the transmission shaft 121 about a first rotation axis C1. Furthermore, the first bevel gear 71 is disposed on the side opposite to the motor 120, across the transmission shaft 121. The second bevel gear 72 meshes with the first bevel gear 71 and rotates about a second rotation axis C2 as the first bevel gear 71 rotates. The first bevel gear 71 and the second bevel gear 72 are disposed within the internal space 2c of the shaft portion 2.

[0071] The transmission shaft 121 extends from the side of the boom 109 into the internal space 2c of the shaft portion 2 along the first rotation axis C1. The transmission shaft 121 is supported by bearings 121a and 121b and is rotatable relative to the boom 109 and the shaft portion 2.

[0072] Furthermore, bearings 121a and 121b may be provided in either the boom 109 and the shaft portion 2, or both the boom 109 and the shaft portion 2. Moreover, if a bearing portion is provided between the boom 109 and the shaft portion 2, bearings 121a and 121b may also be provided in that bearing portion.

[0073] However, as long as the bearings 121a and 121b can support the transmission shaft 121 so that it can rotate freely relative to the stick 109 and the shaft 2, various bearing structures can be used.

[0074] The second bevel gear 72 is formed on the first working output shaft 76 and rotates about the second rotation axis C2. The first working output shaft 76 is arranged on the same axis as the second rotation axis C2 and rotates together with the second bevel gear 72 about the second rotation axis C2. The first working output shaft 76 is disposed inside the shaft portion 2.

[0075] One end of the first working output shaft 76 is rotatably supported by a bearing 76b disposed inside the shaft portion 2. A toothed portion 76c that meshes with the reduction gear 4 is formed on the outer peripheral surface of the other end of the first working output shaft 76.

[0076] <Deceleration Section>

[0077] Figure 4 This is a schematic diagram of the deceleration unit 4.

[0078] like Figure 4 As shown, the reduction unit 4 includes: a cylindrical housing (fixed part) 11; a gear carrier (output part) 14 disposed radially inside the housing 11; and a reduction input part (input part) 18. The reduction input part 18 rotates the gear carrier 14 at a speed reduced by a certain ratio relative to the rotational speed of the first working output shaft 76.

[0079] The housing 11 is fixed to the shaft 2. Thus, the entire reduction gear 4 is combined with the shaft 2. For the reduction gear 4, a rotational driving force from the motor 120 is input to the reduction input 18. The gear carrier 14 is mounted on the opposing surface 111a in the mounting bracket 111, which is opposite to the gear carrier 14 in the direction of the second rotation axis C2. Thus, the entire reduction gear 4 is combined with the mounting bracket 111.

[0080] <Shell>

[0081] An outer flange portion 11a is integrally formed on the outer peripheral surface of the housing 11, protruding radially outward. The cross-section of the outer flange portion 11a along the axial direction is formed into a quadrilateral shape. On the side of the outer flange portion 11a near the axis ( Figure 4 The right side end face 11b is provided with a rotation transmission part 2b. The outer flange 11a is fastened to the rotation transmission part 2b by bolts 53.

[0082] Internal teeth 24 are provided on the inner circumferential surface of the housing 11. The internal teeth 24 are pin-shaped (cylindrical) teeth provided on the inner circumferential surface of the housing 11. Multiple internal teeth 24 are arranged at equal intervals in the circumferential direction.

[0083] <Gear Carrier>

[0084] The gear carrier 14 is rotatably supported on the housing 11 by a pair of main bearings 26 arranged axially spaced apart. The main bearings 26 are, for example, angular contact ball bearings. The gear carrier 14 is arranged on the same axis as the housing 11 and the second axis of rotation C2.

[0085] The gear carrier 14 includes: a base plate portion 32 disposed within the internal space 2c of the shaft portion 2; an end plate portion 30 disposed on the side opposite to the internal space 2c, across the base plate portion 32; and three cylindrical column portions 33 integrally formed with the base plate portion 32.

[0086] The column portion protrudes from the base plate portion 32 toward the end plate portion 30 and is arranged at equal intervals in the circumferential direction. The end plate portion 30 is arranged to contact the top end 33a of the column portion 33. The mounting bracket 111 of the bucket 110 is arranged to contact the side 30a of the end plate portion 30 located on the side opposite to the base plate portion 32. Furthermore, the end plate portion 30 and the mounting bracket 111 are fastened together to the column portion 33 using bolts 34. In addition, a space with a certain width in the axial direction is formed between the base plate portion 32 and the end plate portion 30.

[0087] A pin 36 is provided at a position radially inward of the bolt 34 fixed to the column portion 33 to position the end plate portion 30 relative to the base plate portion 32. The pin 36 is arranged across the column portion 33 and the end plate portion 30.

[0088] Furthermore, the pillar portion 33 does not need to be integrally formed with the base plate portion 32. In this case, for example, the pillar portion 33 can be combined with the base plate portion 32 by means of fastening. Moreover, the pillar portion 33 is not limited to a cylindrical shape. As long as a space with a certain width in the axial direction can be formed between the base plate portion 32 and the end plate portion 30, the shape of the pillar portion 33 can be appropriately modified.

[0089] The end plate portion 30 and the base plate portion 32 are each provided with a plurality of through holes 30c and 32b for insertion of the crankshaft 46, which will be described later. The through holes 30c and 32b are arranged at equal intervals in the circumferential direction.

[0090] <Deceleration Input Section>

[0091] The reduction input unit 18 includes: a plurality of (for example, three in this embodiment) transmission gears 44 that mesh with the teeth 76c of the first working output shaft 76; a plurality of (for example, three in this embodiment) crankshafts 46, one end of which is fixed to the transmission gears 44; and a first external gear (an example of an external gear member) 48a and a second external gear 48b that oscillate and rotate with the rotation of the crankshafts 46.

[0092] A transmission gear 44 is fixed at one end of the crankshaft 46, so that the rotation of the first working output shaft 76 is transmitted to the crankshaft 46 by means of the transmission gear 44.

[0093] The crankshaft 46 rotates around a crankshaft rotation axis C4 that is parallel to the second rotation axis C2. The crankshaft 46 is rotatably supported on the end plate portion 30 by means of a first crankshaft bearing 51. Furthermore, the crankshaft 46 is rotatably supported on the base plate portion 32 by means of a second crankshaft bearing 52. The first crankshaft bearing 51 and the second crankshaft bearing 52 are, for example, tapered roller bearings.

[0094] A first eccentric portion 46a and a second eccentric portion 46b, which are eccentric relative to the axis of the crankshaft 46, are formed at the axial center of the crankshaft 46.

[0095] The first eccentric portion 46a and the second eccentric portion 46b are arranged adjacent to each other in the axial direction between the first crankshaft bearing 51 and the second crankshaft bearing 52. The first eccentric portion 46a is arranged adjacent to the first crankshaft bearing 51. The second eccentric portion 46b is arranged adjacent to the second crankshaft bearing 52. Moreover, the phase angles of the first eccentric portion 46a and the second eccentric portion 46b are offset from each other.

[0096] The crankshaft 46 thus configured is inserted into the through holes 30c and 32b of the end plate portion 30 and the base plate portion 32. Therefore, the crankshaft 46 and the through holes 30c and 32b are arranged in a manner that is equally spaced apart in the circumferential direction.

[0097] A first roller bearing 55a is installed in the first eccentric portion 46a of the crankshaft 46. A second roller bearing 55b is installed in the second eccentric portion 46b. The first roller bearing 55a is, for example, a cylindrical roller bearing.

[0098] The first roller bearing 55a has multiple rollers and a retainer for holding the multiple rollers. The second roller bearing 55b is constructed in the same manner as the first roller bearing 55a. The first external gear 48a and the second external gear 48b rotate oscillatingly with the rotation of the crankshaft 46 by means of the roller bearings 55a and 55b.

[0099] The first external gear 48a and the second external gear 48b are disposed in the space between the base plate portion 32 and the end plate portion 30 of the gear carrier 14. The first external gear 48a and the second external gear 48b have external teeth 49a and 49b that mesh with the internal teeth 24 of the housing 11.

[0100] The first external gear 48a and the second external gear 48b have a first through hole 48c for inserting the column portion 33 and a second through hole 48d for inserting the eccentric portions 46a and 46b of the crankshaft 46.

[0101] The first eccentric portion 46a of the crankshaft 46 and the first roller bearing 55a are inserted into the second through hole 48d of the first external gear 48a. The second eccentric portion 46b of the crankshaft 46 and the second roller bearing 55b are inserted into the second through hole 48d of the second external gear 48b. As a result, the first external gear 48a and the second external gear 48b oscillate and rotate due to the rotation of the crankshaft 46, while meshing with the internal teeth 24 of the housing 11.

[0102] <Outer shell>

[0103] like Figure 3 As shown, the outer casing 6 is formed in an annular shape along the outer peripheral surface 2d1 of the outer casing shaft 2d, which is rotatable about the second rotation axis C2. The outer casing 6 can slide, slide, or move relative to the outer peripheral surface 2d1 of the outer casing shaft 2d in the direction along the second rotation axis C2.

[0104] The outer casing 6 has an end portion 6a that contacts the opposing surface 112a of the mounting bracket portion 112. The end portion 6a is mounted to the opposing surface 112a by means of bolts 54. Thus, the outer casing 6 and the mounting bracket portion 112 are combined into one unit.

[0105] Furthermore, the end face 6a is in contact with the opposite face 112a throughout the entire circumference, which can prevent foreign objects from entering from the outside.

[0106] The end face 2d2 of the housing shaft portion 2d faces the opposing face 112a, and is separated from the opposing face 112a in the direction of the second rotation axis C2. Therefore, even when the housing portion 6 and the mounting bracket portion 112 are rotated integrally around the second rotation axis C2, the end face 2d2 and the opposing face 112a remain separated from each other.

[0107] The end face 6b of the outer casing 6 facing the mounting bracket portion 111 is opposite to the stepped surface 2e. The stepped surface 2e is formed on the shaft portion 2d in such a way that it surrounds the entire circumference of the outer casing shaft portion 2d. A gap is formed between the end face 6b and the stepped surface 2e. A labyrinth seal 9 is provided in this gap.

[0108] <Maze Seal>

[0109] The labyrinth seal 9 is formed in correspondence with the gap formed between the end face 6b and the step face 2e, and is provided around the entire circumference of the shaft portion 2 with the second rotation axis C2 as the center.

[0110] Specifically, the labyrinth seal 9 has a protrusion 9a formed on the step surface 2e and a groove 9b formed on the end face 6b.

[0111] The protrusion 9a protrudes from the stepped surface 2e toward the outer casing 6 and is formed around the second axis of rotation C2. The groove 9b is formed concavely on the end face 6b and is formed in a manner corresponding to the protrusion 9a. Alternatively, the labyrinth seal 9 can be formed by forming the protrusion 9a on the end face 6b and the groove 9b on the stepped surface 2e.

[0112] Furthermore, the separation distance D9 between the protrusion 9a and the groove 9b along the second rotation axis C2 is greater than the distance D2 between the opposite face 112a and the end face 2d2 along the second rotation axis C2.

[0113] A sealing element 9c is provided at a position closer to the second rotation axis C2 than the labyrinth seal 9. The sealing element 9c is provided throughout the entire circumference between the outer casing 6 and the outer casing shaft 2d.

[0114] In addition, a sealing member 9d is provided at the end 6a near the second rotation axis C2. The sealing member 9d is provided throughout the entire circumference between the outer casing 6 and the outer casing shaft 2d.

[0115] Furthermore, the labyrinth seal 9 can also be composed of multiple sets of protrusions and grooves. In this case, the multiple sets of protrusions and grooves are arranged radially. That is, the multiple sets of protrusions and grooves can be arranged concentrically about the second rotation axis C2.

[0116] <Bearings>

[0117] Bearing 8 is a self-aligning bearing, comprising an inner ring 8a, an outer ring 8b, cylindrical rollers 8c1 and 8c2, and a retainer 8d.

[0118] The inner ring 8a is fixed to the outer peripheral surface 2d1 of the outer casing shaft 2d.

[0119] The outer ring 8b is positioned radially upwards and outwards from the inner ring 8a, and is fixed to the inner circumferential surface 6c of the outer casing 6.

[0120] Cylindrical rollers 8c1 and 8c2 are disposed between the inner ring 8a and the outer ring 8b, and a plurality of them are arranged at intervals in the circumferential direction with the second axis of rotation C2 as the center. Moreover, the cylindrical rollers 8c1 and 8c2 are arranged in a direction along the second axis of rotation C2.

[0121] The retainer 8d is formed in a ring shape around the second rotation axis C2 and is disposed between the inner ring 8a and the outer ring 8b. The retainer 8d holds the cylindrical rollers 8c1 apart about the second rotation axis C2, and also holds the cylindrical rollers 8c1 so that they can rotate about the second rotation axis C2. Similarly, the retainer 8d holds the cylindrical rollers 8c2 apart about the second rotation axis C2, and also holds the cylindrical rollers 8c2 so that they can rotate about the second rotation axis C2.

[0122] Cylindrical rollers 8c1 and 8c2 are supported between the inner ring 8a and the outer ring 8b such that the side of the axes of cylindrical rollers 8c1 and 8c2 that are closer to each other is farther from the second axis of rotation C2 than the side that is farther away from each other. The outer circumferential surface of cylindrical roller 8c1 is bulging with a radial dimension larger at its central portion in the axial direction. Similarly, the outer circumferential surface of cylindrical roller 8c2 is bulging with a radial dimension larger at its central portion in the axial direction.

[0123] Furthermore, the opposing surfaces of the inner ring 8a and the outer ring 8b are formed into curved surfaces corresponding to the outer peripheral surfaces of the cylindrical rollers 8c1 and 8c2.

[0124] The inner circumferential surface of the inner ring 8a is fixed relative to the outer circumferential surface 2d1 of the housing shaft portion 2d by an interference fit, for example. The end of the inner ring 8a located on the mounting bracket 111 side abuts against the step 2f formed in the shaft portion 2. The end of the inner ring 8a located on the mounting bracket 112 side is separated from the inner end surface 6d of the housing portion 6.

[0125] The outer peripheral surface of the outer ring 8b is fixed relative to the inner peripheral surface 6c of the outer housing 6 by a clearance fit, for example. The end of the outer ring 8b located on the mounting bracket 112 side is separated from the inner end surface 6d of the outer housing 6.

[0126] Therefore, the end of the bearing 8 located on the mounting bracket 112 side is separated from the inner end face 6d of the housing portion 6.

[0127] <Operation of the drive transmission device>

[0128] Next, the operation of the drive transmission device 1 will be explained.

[0129] If Figure 2 Driven by the motor 120 mounted on the boom 109, the rotation of the motor shaft 120a is transmitted to the first bevel gear 71 of the drive transmission device 1 via the transmission shaft 121. This causes the second bevel gear 72, which meshes with the first bevel gear 71, to rotate. Furthermore, the rotation of the second bevel gear 72 is transmitted to the reduction gear 4 via the first working output shaft 76.

[0130] If the transmission gear 44, which meshes with the toothed portion 76c, rotates due to the rotation of the first working output shaft 76, then the crankshaft 46 and the transmission gear 44 rotate together around the crankshaft rotation axis C4. If the crankshaft 46 rotates, the first eccentric portion 46a and the second eccentric portion 46b oscillate. Consequently, as the first eccentric portion 46a oscillates, the first external gear 48a rotates while meshing with the internal gear 24. Similarly, as the second eccentric portion 46b oscillates, the second external gear 48b rotates while meshing with the internal gear 24.

[0131] Thus, crankshaft 46 rotates around crankshaft rotation axis C4 and revolves around second rotation axis C2.

[0132] In this embodiment, the post portion 33, which passes through the first through hole 48c formed in the external gears 48a and 48b, is fixed to the base plate portion 32. As a result, the gear carrier 14 rotates relative to the housing 11 about the second rotation axis C2 at a speed reduced compared to the first working output shaft 76.

[0133] The other end 109b of the stick 109 is fixed to the housing 11 via the shaft 2. The mounting bracket 111 of the bucket 110 is fixed to the end plate 30 of the gear frame 14.

[0134] Furthermore, the outer casing 6 is rotatable relative to the shaft 2 fixed to the housing 11 in a state coaxial with the gear carrier 14. Additionally, a mounting bracket 112 for the bucket 110 is fixed to the outer casing 6.

[0135] Therefore, the gear carrier 14 and the outer casing 6 are integrally rotated with the bucket 110 around the second rotation axis C2. Thus, by driving the motor 120 provided on the stick 109, the bucket 110 can be rotated relative to the stick 109 around the second rotation axis C2.

[0136] The first working output shaft 76 of the reduction unit 4 functions as an input shaft that inputs the rotation of the motor shaft 120a to the reduction input unit 18. The gear carrier 14 functions as an output shaft that reduces the rotation of the first working output shaft 76 and outputs the rotation to the bucket 110.

[0137] Furthermore, the gear carrier 14 of the reduction unit 4 and the housing 6, which is coaxially arranged therewith, are configured in a manner approximately symmetrical with respect to the first rotation axis C1 along the direction of the second rotation axis C2. In other words, the reduction unit 4 and the housing 6 are respectively arranged in separate positions on the coaxial direction of the second rotation axis C2 as structures corresponding to the bearings.

[0138] The bucket 110 has mounting surfaces 111a and 112a, which are arranged to clamp the end plate portion 30 of the deceleration unit 4 and the end portion 6a of the outer shell portion 6, respectively, and are fixed by bolts. Thus, it becomes a double-support structure that supports the weight of the bucket 110 and external forces in two parts.

[0139] Therefore, unlike cantilever structures, it can evenly support external loads, and its simple structure can prevent the drive transmission device 1 from becoming too large. In addition, it can suppress the offset of external loads such as radial loads and torque loads acting on the drive transmission device 1, and can extend the life of the structural components of the drive transmission device 1.

[0140] The following describes the assembly method of the construction machinery equipped with the drive transmission device 1 in this embodiment. The assembly related to the drive transmission device 1 will be described.

[0141] Figures 5-8 This is a process diagram illustrating the assembly method of the drive transmission device 1 in this embodiment.

[0142] Assembly Method

[0143] The assembly method of the drive transmission device 1 in this embodiment includes a preparation process, a gap shortening process, an insertion process, a deceleration part installation process (installation process), a gap extension process, and a housing part installation process (installation process).

[0144] In the assembly of the drive transmission device 1, firstly, as a preparatory step, such as... Figure 5 As shown, the speed reduction unit 4 is inserted into the internal space 2c of the shaft 2 (refer to...). Figure 4 The opening is then sealed. At this time, the reduction gear 4 and the shaft 2 are pre-fixed to each other using bolts 53. Simultaneously, the outer casing 6 is pre-assembled onto the outer casing shaft 2d using bearings 8. Furthermore, the outer casing 6 can move relative to the outer casing shaft 2d in the direction of the second rotation axis C2.

[0145] Next, as a gap-reduction process, such as in Figure 5 As indicated by arrow As1, the outer casing 6 and the shaft 2 are brought closer together in the direction along the second rotation axis C2. That is, the outer casing 6 is moved towards the deceleration unit 4 by sliding relative to the outer peripheral surface 2d1 of the outer casing shaft 2d. Furthermore, the gap between the end face 6b forming the labyrinth seal 9 and the stepped surface 2e is shortened (see reference). Figure 3 ).

[0146] Therefore, as Figure 5 As shown, with Figure 3 Compared to the assembled state shown, this state is one where the dimension D46 from the end face 4a of the deceleration unit 4 to the end 6a of the outer casing 6 in the direction of the second rotation axis C2 is shortened. For example... Figure 5 As shown, dimension D46 is smaller than the separation dimension D111 between the opposing surfaces 111a of the mounting bracket portion 111 and 112a of the mounting bracket portion 112 in the direction of the second rotation axis C2.

[0147] Next, as an insertion process, after the gap shortening process is completed, as in Figure 5 As indicated by arrow As2, the shaft portion 2 is inserted between the opposing surfaces 111a of the mounting bracket portion 111 and 112a of the mounting bracket portion 112, in a direction intersecting the second rotation axis C2. As described above, the shaft portion 2 is assembled with a reduction gear 4, a housing portion 6, and a bearing 8.

[0148] The dimension D46 is smaller than the separation dimension D111, thus the insertion process can be easily performed.

[0149] Next, as part of the speed reduction unit installation process (installation process), such as in Figure 6 As indicated by arrow As3, the shaft 2, which houses the reduction gear 4, housing 6, and bearing 8, is brought close to the mounting bracket 111 along the second rotation axis C2. This allows the end face 4a of the reduction gear 4 to contact the opposing surface 111a. In this state, as in... Figure 6 As shown by arrow As4, the mounting bracket 111 is fastened to the reduction gear 4 using bolts 34 (see reference). Figure 4 Specifically, the end plate portion 30 and the mounting bracket 111 are fastened to the column portion 33 of the gear carrier 14 using bolts 34 (see reference). Figure 4 ).

[0150] At this time, the gap between the end face 6b forming the labyrinth seal 9 and the step face 2e is shortened.

[0151] Next, as a gap elongation process, such as in Figure 7As indicated by arrow As5, after the insertion process, the outer casing 6 and the shaft 2 are moved away from each other in the direction of the second rotation axis C2, causing the gap formed between the outer casing 6 and the shaft 2 to lengthen. At this time, the mounting bracket 112 is brought close to the outer casing 6 until it contacts. As a result, the opposing surface 112a contacts the end face 6a. Consequently, the gap between the end face 6b and the stepped surface 2e widens, forming the labyrinth seal 9.

[0152] Next, as part of the outer casing assembly process (assembly process), such as in Figure 7 As shown by arrow As6, after the gap elongation process, with the end face 6a of the outer casing 6 in contact with the opposing surface 112a, the mounting bracket 112 is fastened to the outer casing 6 using bolts 54 (see reference). Figure 3 ).

[0153] Thus, the assembly of drive transmission device 1 is completed.

[0154] According to this embodiment, the outer casing 6 assembled on the outer casing shaft 2d can move in the direction along the second rotation axis C2. Therefore, by moving the outer casing 6 in the direction of the second rotation axis C2, the gap in the direction of the second rotation axis C2 generated between the opposing surfaces 111a and 112a, which serve as the mounting surfaces when the bucket 110 is mounted, can be adjusted.

[0155] Therefore, in the drive transmission device 1 in which the bearing 8 is arranged between the shaft 2 and the housing 6, the housing 6 can be moved relative to the shaft 2 without the need for clearance adjustment.

[0156] Moreover, according to this embodiment, both the first and second conventional problems can be solved simultaneously.

[0157] The first problem is the need to adjust the clearance in the direction of the rotation axis during the assembly of buckets, etc. The second problem is the need for sealing to prevent the bearings outside the shaft from being exposed to sand, etc., from the perspective of the operating environment.

[0158] Furthermore, the shaft portion 2 and the outer casing portion 6 are respectively provided with a protruding strip 9a with a stepped surface 2e and a groove 9b with an end face 6b. Moreover, the top tip of the protruding strip 9a can be kept inside the groove 9b, and the distance between the protruding strip 9a and the groove 9b can be set to an appropriate distance by utilizing the axial movement of the outer casing portion 6 when the bucket 110 is installed. This ensures the sealing performance of the labyrinth seal 9.

[0159] Therefore, even if the bearing 8 installed in the inner circumference of the housing 6 is at risk of being exposed to sand, for example, during excavation, the labyrinth seal 9 can be used to seal the bearing 8.

[0160] Furthermore, in this embodiment, the outer diameter of the outer housing 6 can be set to be approximately equal to the outer diameter of the deceleration unit 4, i.e., the outer diameter of the outer flange 11a. At this time, in the radial direction relative to the second rotation axis C2, the radial dimension of the mounting position (connection position) of the bolt 53 and the radial dimension of the mounting position (connection position) of the bolt 54 can be set to be approximately equal.

[0161] Therefore, it is possible to suppress the deviation of external loads such as radial loads and torque loads acting on the drive transmission device 1 relative to the second rotation axis C2, and to extend the lifespan of the structural components of the drive transmission device 1.

[0162] Furthermore, in this embodiment, the outer diameter of the bearing 8 can be set to be approximately equal to the outer diameter of the gear carrier 14. As a result, the deviation of external loads such as radial loads and torque loads acting on the drive transmission device 1 relative to the second rotation axis C2 can be suppressed, and the lifespan of the structural components of the drive transmission device 1 can be extended.

[0163] Furthermore, in this embodiment, the distance from the first rotation axis C1 to the bearing 8 along the second rotation axis C2 can be set to be approximately equal to the distance from the first rotation axis C1 to the deceleration unit 4 along the second rotation axis C2 (i.e., the distance from the first rotation axis C1 to the center position of the pair of main bearings 26 along the second rotation axis C2).

[0164] Therefore, it is possible to suppress the deviation of external loads such as radial loads and torque loads acting on the drive transmission device 1 relative to the second rotation axis C2, and to extend the lifespan of the structural components of the drive transmission device 1.

[0165] Furthermore, in this embodiment, the radial separation distance between the protrusion 9a of the stepped surface 2e and the groove 9b of the end face 6b is set to about a few mm (for example, about 0.5 mm to 1.5 mm), thereby ensuring sufficient sealing.

[0166] Furthermore, in the assembly process of this embodiment, it is also possible to perform the assembly process in the following order after the insertion process: housing part installation process (installation process), gap extension process, and deceleration part installation process (installation process).

[0167] (Second Implementation)

[0168] Hereinafter, a second embodiment of the drive transmission device of the present invention will be described based on the accompanying drawings.

[0169] Figure 8This is a schematic structural diagram showing the dimensions and assembly process of the drive transmission device in this embodiment. In this embodiment, the difference from the first embodiment described above lies in the aspects related to the position limiting part 5. Therefore, the same reference numerals are used to label the structures corresponding to those in the first embodiment, excluding the position limiting part 5, and their descriptions are omitted.

[0170] like Figure 8 As shown, in this embodiment, the drive transmission device 1 has position limiting portions 5 formed on the opposing surface 111a opposite to the end face 4a of the deceleration unit 4 and the opposing surface 112a opposite to the end face 6a of the housing unit 6 in the direction of the second rotation axis C2. The position limiting portion 5 includes a protrusion 5a, a protrusion 5b, a recess 5c, and a recess 5d.

[0171] A protrusion 5a is formed on the end face 4a of the deceleration section 4. A recess 5c is formed on the opposite face 111a. A protrusion 5b is formed on the end face 6a of the outer shell section 6. A recess 5d is formed on the opposite face 112a.

[0172] Both protrusions 5a and 5b are formed around the second rotation axis C2, covering the entire circumference, and are formed in a manner that gives them a circular shape when viewed from the direction along the second rotation axis C2. In addition, protrusions 5a and 5b may be formed continuously or intermittently, or they may be formed into a semi-circular shape or a segmented circular shape.

[0173] In the deceleration section installation process (installation process), the protrusion 5a is aligned with the recess 5c and fitted into the recess 5c. This allows for positional constraint between the end face 4a of the deceleration section 4 and the opposing face 111a. Similarly, in the outer casing installation process (installation process), the protrusion 5b is aligned with the recess 5d and fitted into the recess 5d. This allows for positional constraint between the outer casing 6 and the opposing face 112a.

[0174] In the direction along the second rotation axis C2, the combined value of the height dimensions D5a of protrusion 5a and D5b of protrusion 5b is smaller than the difference between dimension D46 and separation dimension D111 in the gap shortening process. Furthermore, the difference between the combined value of height dimension D5a, height dimension D5b, and dimension D46 in the gap shortening process and the separation dimension D111 is smaller than the separation distance D9 of the gap in the labyrinth seal 9 (see reference). Figure 3 )Small.

[0175] According to this embodiment, the ease of positioning can be improved by utilizing the position limiting part 5. Furthermore, by using bolts to move the outer casing part 6 in the direction of the second rotation axis C2, the gap in the direction of the second rotation axis C2 generated between the opposing surfaces 111a and 112a, which serve as the mounting surfaces when the bucket 110 is installed, can be adjusted.

[0176] Therefore, in the drive transmission device 1 in which the bearing 8 is arranged between the shaft 2 and the housing 6, the housing 6 can be moved relative to the shaft 2 without the need for clearance adjustment.

[0177] Furthermore, in this embodiment, a protrusion 9a with a stepped surface 2e and a groove 9b with an end face 6b are respectively provided on the shaft portion 2 and the outer casing portion 6. Moreover, by maintaining the top end of the protrusion 9a inside the groove 9b and utilizing the axial movement of the outer casing portion 6 when installing the bucket 110, the distance between the protrusion 9a and the groove 9b is set to an appropriate distance. This ensures the sealing performance of the labyrinth seal 9.

[0178] Therefore, even if the bearing 8 installed in the inner circumference of the housing 6 is at risk of being exposed to sand, for example, during excavation, the labyrinth seal 9 can be used to seal the bearing 8.

[0179] In this embodiment, the same effects as in the first embodiment are achieved. Furthermore, this embodiment reduces the impact of improved installability and increased assembly accuracy on defects.

[0180] (Third Implementation)

[0181] Hereinafter, a third embodiment of the drive transmission device of the present invention will be described based on the accompanying drawings.

[0182] Figure 9 This is a schematic structural diagram showing the dimensions and assembly process of the drive transmission device in this embodiment. In this embodiment, the difference from the second embodiment described above lies in the aspects relating to the protrusions and recesses constituting the position limiting portion 5. Therefore, other structures corresponding to those in the second embodiment described above are labeled with the same reference numerals, and their descriptions are omitted.

[0183] like Figure 9 As shown, in this embodiment, the drive transmission device 1 has position limiting parts 5 formed on the opposing surface 111a and the opposing surface 112a respectively.

[0184] A recess 5c is formed on the end face 4a of the deceleration section 4. A protrusion 5a is formed on the opposite face 111a. A recess 5d is formed on the end face 6a of the outer casing section 6. A protrusion 5b is formed on the opposite face 112a.

[0185] In the deceleration section installation process (installation process), the protrusion 5a is aligned with the recess 5c and fitted into the recess 5c. This allows for positional constraint between the end face 4a of the deceleration section 4 and the opposing face 111a. Furthermore, in the outer casing installation process (installation process), the protrusion 5b is aligned with the recess 5d and fitted into the recess 5d. This allows for positional constraint between the outer casing 6 and the opposing face 112a.

[0186] In the direction along the second rotation axis C2, the combined value of the height dimensions D5a of protrusion 5a and D5b of protrusion 5b is smaller than the difference between dimension D46 and separation dimension D111 in the gap shortening process. Furthermore, the difference between the combined value of height dimension D5a, height dimension D5b, and dimension D46 in the gap shortening process and the separation dimension D111 is smaller than the separation distance D9 of the gap in the labyrinth seal 9 (see reference). Figure 3 )Small.

[0187] According to this embodiment, the ease of positioning can be improved by utilizing the position limiting part 5. Furthermore, by using bolts to move the outer casing part 6 in the direction of the second rotation axis C2, the gap in the direction of the second rotation axis C2 generated between the opposing surfaces 111a and 112a, which serve as the mounting surfaces when the bucket 110 is installed, can be adjusted.

[0188] Therefore, in the drive transmission device 1 in which the bearing 8 is arranged between the shaft 2 and the housing 6, the housing 6 can be moved relative to the shaft 2 without the need for clearance adjustment.

[0189] Furthermore, in this embodiment, a protrusion 9a with a stepped surface 2e and a groove 9b with an end face 6b are respectively provided on the shaft portion 2 and the outer casing portion 6. Moreover, by maintaining the top end of the protrusion 9a inside the groove 9b and utilizing the axial movement of the outer casing portion 6 when installing the bucket 110, the distance between the protrusion 9a and the groove 9b is set to an appropriate distance. This ensures the sealing performance of the labyrinth seal 9.

[0190] Therefore, even if the bearing 8 installed in the inner circumference of the housing 6 is at risk of being exposed to sand, for example, during excavation, the labyrinth seal 9 can be used to seal the bearing 8.

[0191] Therefore, this embodiment can also achieve the same effect as the second embodiment.

[0192] (Fourth implementation)

[0193] Hereinafter, a fourth embodiment of the drive transmission device of the present invention will be described based on the accompanying drawings.

[0194] Figure 10This is a schematic structural diagram showing the drive transmission device in this embodiment. In this embodiment, the difference from the first embodiment described above lies in the aspects related to the bearing 8. Therefore, structures other than the bearing 8 that correspond to those in the first embodiment described above are labeled with the same reference numerals, and their descriptions are omitted.

[0195] like Figure 10 As shown, in the bearing 8 of this embodiment, the inner circumferential surface of the inner ring 8a is clearance-fitted with the outer circumferential surface 2d1 of the housing shaft portion 2d. The outer circumferential surface of the outer ring 8b is interference-fitted with the inner circumferential surface 6c of the housing portion 6.

[0196] The end of the inner ring 8a located on the mounting bracket 111 side is separated from the surface 2g of the shaft portion 2. The end of the inner ring 8a located on the mounting bracket 112 side is separated from the inner end surface 6d of the outer casing portion 6.

[0197] The end of the outer ring 8b located on the mounting bracket 111 side is separated from the surface 2g of the shaft portion 2. The end of the outer ring 8b located on the mounting bracket 112 side abuts against the step 6f formed in the outer casing portion 6.

[0198] Therefore, the end of the bearing 8 located on the mounting bracket 111 side is separated from the surface 2g of the shaft portion 2.

[0199] Therefore, in this embodiment, during the preparation process, the bearing 8 can be embedded into the housing portion 6 and assembled onto the shaft portion 2.

[0200] In this embodiment, the same effects as in the first embodiment are achieved. Furthermore, in this embodiment, even if the nature of the load applied to the bearing 8 changes due to the way the load is applied to the working joint during actual use of the excavator, an appropriate fit can be selected. This prevents overload and damage to the bearing 8.

[0201] In the above embodiments, the first component is defined as the boom 109 and the second component as the bucket 110, but the structure is not limited to this. For example, the first component may be defined as the boom 108 and the second component as the boom 109, and a drive transmission device 1 may be provided. Furthermore, the first component may be defined as the rotating body (main body) 103 and the second component as the boom 108, and a drive transmission device 1 may be provided. Moreover, it is also possible to construct a construction machine where the first component is the boom 109 and the second component is other accessories to replace the bucket 110.

[0202] In the embodiments disclosed in this specification, a component composed of multiple objects can be made into one integrated object; conversely, a component composed of a single object can be divided into multiple objects. Regardless of whether it is integrated or not, it can be constructed in a manner that achieves the purpose of the invention.

[0203] Furthermore, the present invention includes the following forms.

[0204] <1> The drive transmission device of the present invention includes:

[0205] A shaft portion that is rotatable relative to at least two support portions, which are rotatable integrally about a rotation axis and are arranged opposite each other separately along the direction of the rotation axis, and the shaft portion is located between the support portions in the direction of the rotation axis.

[0206] A reduction gear is mounted on the shaft portion, and a rotational driving force from a drive source is input from the input portion of the reduction gear. The output portion of the reduction gear is mounted on the opposite surface located inside the first bracket portion constituting the bracket portion, in the direction of the rotation axis.

[0207] The outer casing is connected to the shaft portion in a manner that allows it to rotate freely about the axis of rotation relative to the shaft portion, and the outer casing is mounted on the opposite surface located inside the direction of the axis of rotation in the second bracket portion that constitutes the bracket portion.

[0208] <2> The construction machinery of the present invention includes:

[0209] A first component has a drive source that generates rotational force; and a second component is connected to the first component in a rotatable manner about a rotation axis by means of a drive transmission device.

[0210] The drive transmission device includes:

[0211] At least two support portions are disposed on the second member and are arranged opposite to each other separately along the direction of the rotation axis;

[0212] A shaft portion, which is connected to the first member, and is located between the support portions in the direction of the rotation axis;

[0213] A reduction gear is mounted on the shaft portion, and a rotational driving force from the drive source is input from the input portion of the reduction gear. The output portion of the reduction gear is mounted on the opposite surface located inside the first bracket portion constituting the bracket portion, in the direction of the rotation axis.

[0214] The outer casing is rotatably connected to the shaft relative to the shaft about the axis of rotation, and is mounted on the inner side of the second bracket portion constituting the bracket portion, located in the direction of the axis of rotation.

[0215] The shaft portion and the housing portion are movable relative to each other in the direction of the rotation axis.

[0216] The outer casing is formed in a ring shape and fits around the shaft portion.

[0217] A gap is formed between the outer periphery of the outer casing and the outer periphery of the shaft in the direction of the rotation axis.

[0218] A labyrinth seal is provided in the gap formed between the outer periphery of the outer casing and the outer periphery of the shaft.

Claims

1. A drive transmission device, wherein, The drive transmission device has the following features: Shaft portion; A speed reduction unit, which is mounted on the shaft portion; and The housing portion is rotatably connected to the shaft portion relative to the shaft portion about the rotation axis of the output of the reduction unit, and the housing portion is mounted on the first bracket portion. The deceleration unit has: The input section receives the rotational driving force from the drive source. as well as The output section is mounted on the second bracket section, which is integrated with the first bracket section, and the second bracket section and the first bracket section are arranged opposite each other separately along the rotation axis. The deceleration unit and the outer casing are respectively positioned separately on the rotation axis.

2. The drive transmission device according to claim 1, wherein, The shaft and the housing are movable relative to each other in the direction of the axis of rotation.

3. The drive transmission device according to claim 2, wherein, The outer casing is formed in a ring shape and fits around the shaft portion. A gap is formed between the outer periphery of the outer casing and the outer periphery of the shaft in the direction of the rotation axis.

4. The drive transmission device according to claim 3, wherein, A labyrinth seal is provided between the outer periphery of the outer casing and the outer periphery of the shaft.

5. The drive transmission device according to claim 3 or 4, wherein, At least one of the first and second bracket portions has an assembly position limiting portion with a predetermined height facing inward along the rotation axis on its opposite surface. Along the direction of the rotation axis, the separation distance of the gap is greater than the height of the assembly position limiting part.

6. The drive transmission device according to any one of claims 2 to 4, wherein, A bearing is provided between the outer casing and the shaft. The bearing is interference-fitted with either the housing portion or the shaft portion, and clearance-fitted with the other.

7. The drive transmission device according to any one of claims 1 to 4, wherein, The radial dimension of the connection position between the outer shell portion and the first support portion about the axis of rotation is equal to the radial dimension of the connection position between the deceleration portion and the second support portion about the axis of rotation.

8. A construction machine, wherein, This construction machinery has the following features: Shaft portion; A speed reduction unit, which is mounted on the shaft portion; and The outer casing is rotatably connected to the shaft relative to the shaft about a rotation axis, and is mounted on the first bracket. The deceleration unit has: The input section receives the rotational driving force from the drive source. as well as The output section is mounted on the second bracket section. The second support portion is integrated with the first support portion, and the second support portion and the first support portion are separately arranged opposite each other along the direction of the rotation axis. The output section is mounted on the second bracket section and rotates about the rotation axis. The shaft portion and the housing portion are movable relative to each other in the direction of the rotation axis. The outer casing is formed in a ring shape and fits around the shaft portion. A gap is formed between the outer periphery of the outer casing and the outer periphery of the shaft in the direction of the rotation axis. A labyrinth seal is provided between the outer periphery of the outer casing and the outer periphery of the shaft. At least one of the first and second bracket portions has an assembly position limiting portion with a predetermined height facing inward along the rotation axis on its opposite surface. Along the direction of the rotation axis, the separation distance of the gap is greater than the height of the assembly position limiting part. A bearing is provided between the outer casing and the shaft. The bearing is interference-fitted with either the housing portion or the shaft portion, and clearance-fitted with the other. The radial dimension of the connection position between the outer shell portion and the first support portion about the axis of rotation is equal to the radial dimension of the connection position between the deceleration portion and the second support portion about the axis of rotation.

9. A method for assembling construction machinery, which is the method for assembling construction machinery according to claim 8, wherein, The assembly method of this construction machinery has the following characteristics: The gap shortening process involves bringing the outer casing and the shaft closer together in the direction of the rotation axis, thereby shortening the gap formed between the outer casing and the shaft. In the insertion process, after the gap shortening process, the shaft portion is inserted between the support portions from a direction intersecting the rotation axis; In the gap elongation process, after the insertion process, the outer shell portion and the shaft portion are moved away from each other in the direction of the rotation axis, thereby elongating the gap formed between the outer shell portion and the shaft portion; In the installation process, the output part of the deceleration unit is installed on the opposing surface located on the inner side of the second bracket part in the direction of the rotation axis. as well as In the installation process, the outer casing is installed on the opposing surface located inside the first bracket in the direction of the rotation axis.

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