Roller Support Structure

Abstract

To provide a roller support structure that is able to prevent leakage of a lubricant from an end of a support shaft and is easily disassembled and assembled.SOLUTION: A roller support structure (20) includes: a support shaft (21) supported by a side frame of a work machine; and a roller (22) rotatably supported by the support shaft (21) and configured to guide a crawler belt wound around the side frame to rotate. An oil reservoir (21c) for storing a lubricant is formed between the support shaft (21) and the roller (22). This structure is provided with a sealing member (25) that seals an end of the support shaft (21) across a gap (31b, 31c) in which an oil film is formed by the lubricant supplied from the oil reservoir (21c).SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a roller support structure that supports rollers that guide a crawler belt. [Background technology]

[0002] Conventionally, crawlers mounted on work machines include a track wound around a side frame and a plurality of rollers that rotate in contact with the inner circumferential surface of the track to guide the track as it moves. Patent Document 1 discloses a roller support structure that supports the rollers relative to the side frame.

[0003] The roller support structure disclosed in Patent Document 1 prevents the lubricating oil stored between the spindle and the roller from leaking out by attaching O-rings with different temperature characteristics to two axially adjacent ring grooves at the end of the spindle. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-020608 Summary of the Invention [Problem to be solved by the invention]

[0005] However, to install the O-ring at the back, it is necessary to go over the ring groove at the front, which can damage the O-ring during installation and cause oil leaks.In addition, since lubricating oil is not supplied beyond the O-ring, there is also the issue that the end of the shaft can rust and become difficult to disassemble.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and its object is to provide a roller support structure that prevents leakage of lubricating oil from the end of the support shaft and that is easy to disassemble and assemble. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides a roller support structure including a support shaft supported on a side frame of a work machine, and a roller rotatably supported on the support shaft and guiding a crawler belt wound around the side frame, wherein an oil reservoir for storing lubricating oil is formed between the support shaft and the roller, provided at both ends of the support shaft, a sealing member for sealing the end of the support shaft across a gap where an oil film is formed by the lubricating oil supplied from the oil reservoir; a pin provided at each end of the support shaft to fix the sealing member to the support shaft; Equipped with a support shaft through-hole that penetrates radially through an end of the support shaft is formed in the support shaft, and the sealing member has a bottom wall that covers the axial end face of the support shaft, and a cylindrical wall that protrudes from the outer periphery of the bottom wall in the axial direction of the support shaft to cover the peripheral surface of the support shaft across the gap, and in which a pair of cylindrical wall through-holes that penetrate radially through the support shaft are formed, the pins are inserted into the support shaft through-hole and the pair of cylindrical wall through-holes to fix the sealing member to the support shaft, and a lubricating oil filler port that opens outward and communicates with the gap is formed in the bottom wall of one of the sealing members provided at both end portions of the support shaft, and the location where the lubricating oil filler port and the gap communicate is located between the pins provided at both end portions of the support shaft, It is characterized by the following. [Effects of the Invention]

[0008] According to the present invention, it is possible to obtain a roller support structure that prevents leakage of lubricating oil from the end of the support shaft and that is easy to disassemble and assemble. Note that problems, configurations, and effects other than those described above will become clear from the description of the following embodiments. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a side view of a hydraulic excavator, which is a representative example of a work machine according to the present invention. [Figure 2] FIG. 10 is a view showing a roller support structure supported by a side frame. [Figure 3] FIG. 2 is an exploded perspective view of the roller support structure. [Figure 4] FIG. 2 is an exploded cross-sectional view of the roller support structure. [Figure 5] FIG. 2 is a perspective cross-sectional view of the roller support structure taken along a plane parallel to the direction in which the pins extend. [Figure 6] FIG. 1 is a cross-sectional perspective view of the roller support structure taken along a plane passing through the air holes and the lubricant supply port. [Figure 7] FIG. 4 is a cross-sectional view of the roller support structure taken along a plane passing through the air holes and the lubricant supply port. [Figure 8] 10A and 10B are diagrams showing variations of grooves provided on a shaft. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of a work machine according to the present invention will be described with reference to the drawings. Fig. 1 is a side view of a hydraulic excavator 1, which is a representative example of a work machine according to the present invention. In this specification, front, back, left, and right are based on the viewpoint of an operator who is on board and operating the hydraulic excavator 1, unless otherwise specified.

[0011] The hydraulic excavator 1 includes a lower traveling body 2 and an upper rotating body 3 supported on the lower traveling body 2. The lower traveling body 2 and the upper rotating body 3 are an example of a vehicle body. In this embodiment, a crawler-type work machine will be described using the hydraulic excavator 1 equipped with a crawler-type lower traveling body 2 as an example. However, the present invention is not limited to the hydraulic excavator 1 and can be applied to any work machine equipped with a crawler device 10 (for example, a crane).

[0012] The lower traveling body 2 includes a center frame (not shown) that supports the upper rotating body 3 so that it can rotate, and side frames 8 provided on the left and right sides of the center frame. Each of the pair of left and right side frames 8 supports a crawler device 10. The crawler device 10 is driven to cause the hydraulic excavator 1 to travel.

[0013] The upper rotating body 3 is rotatably supported on the lower traveling body 2. The driving force of a swing motor (not shown) is transmitted to the upper rotating body 3, causing it to swing relative to the lower traveling body 2. The upper rotating body 3 mainly comprises a swing frame 5 serving as a base, a front working implement 4 attached to the center of the front end of the swing frame 5 so as to be able to swing up and down, a cab (operator's seat) 7 located on the front left side of the swing frame 5, and a counterweight 6 located at the rear end of the swing frame 5.

[0014] The front working implement 4 includes a boom 4a supported on the upper rotating body 3 so that it can be raised and lowered, an arm 4b supported swingably at the tip of the boom 4a, a bucket 4c supported swingably at the tip of the arm 4b, and hydraulic cylinders 4d, 4e, and 4f that drive the boom 4a, arm 4b, and bucket 4c. The counterweight 6 is used to balance the weight of the front working implement 4, and is a heavy object that has an arc shape when viewed from above.

[0015] The cab 7 has an internal space in which an operator who operates the hydraulic excavator 1 sits. Inside the cab 7, there is a seat (not shown) on which the operator sits, and operating devices (steering wheel, pedals, levers, switches, etc.) that the operator seated in the seat operates. When the operator sitting in the cab 7 operates the operating devices, the lower traveling body 2 travels, the upper rotating body 3 rotates, and the front working implement 4 operates.

[0016] The crawler device 10 mainly comprises a travel motor 11 supported on the rear end of the side frame 8, an idler 12 supported on the front end of the side frame 8, a track 13 that rotates around the output gear of the travel motor 11 and the idler 12, and a plurality of roller support structures 20 that guide the rotating track 13. When the travel motor 11 rotates due to the driving force of an engine (not shown), the track 13 rotates between the output gear of the travel motor 11 and the idler 12.

[0017] 2 is a diagram showing roller support structures 20 supported by side frames 8. As shown in FIG. 2, multiple roller support structures 20 are arranged at predetermined intervals in the front-to-rear direction on the underside of side frames 8. The roller support structures 20 support rollers 22 rotatably around support shafts 21 extending in the left-to-right direction. The rollers 22 supported by the roller support structures 20 come into contact with the inner circumferential surfaces of the crawler belts 13. When the crawler belts 13 rotate, the rollers 22 rotate on their own axes, thereby guiding the crawler belts 13.

[0018] Fig. 3 is an exploded perspective view of roller support structure 20. Fig. 4 is an exploded cross-sectional view of roller support structure 20. Fig. 5 is a cross-sectional perspective view of roller support structure 20 taken along a plane parallel to the extension direction of pins 26. Fig. 6 is a cross-sectional perspective view of roller support structure 20 taken along a plane passing through air holes 25f and lubricant oil supply port 25g. Fig. 7 is a cross-sectional view of roller support structure 20 taken along a plane passing through air holes 25f and lubricant oil supply port 25g.

[0019] 3 and 4, the roller support structure 20 mainly includes a support shaft 21, a roller 22, a bushing 23, a floating seal 24, a collar 25, a pin 26, O-rings 27 and 28, and caps 29 and 30. The roller support structure 20 includes two of each of the roller 22, bushing 23, floating seal 24, collar 25, pin 26, O-rings 27 and 28, and cap 29. These have the same shape and are attached to both ends of the support shaft 21 in opposite directions.

[0020] The support shaft 21 has a cylindrical outer shape. A groove 21a extending in the axial direction is formed on the circumferential surface of the support shaft 21. The groove 21a is formed over the entire axial area of ​​the support shaft 21. The groove 21a is open to both end surfaces of the support shaft 21 in the axial direction. A pair of support shaft through-holes 21b that penetrate in the radial direction is formed at the end of the support shaft 21. Note that the "end of the support shaft 21" refers to the portion that is located outside the bush 23 when the roller support structure 20 is assembled. In addition, the end of the support shaft 21 according to this embodiment does not have a circumferential groove for accommodating an O-ring, and no O-ring is attached.

[0021] The rollers 22 have a generally cylindrical outer shape. A pair of protruding portions 22a, 22b are formed on the outer peripheral surface of the rollers 22, protruding from both axial ends and continuing in the circumferential direction. The protruding portions 22a, 22b abut against the inner peripheral surface of the crawler belt 13. The pair of rollers 22 are fitted onto the support shaft 21 via bushings 23 at positions adjacent to each other in the axial direction. The pair of rollers 22 are rotatably supported on the support shaft 21.

[0022] 4 to 7, an oil reservoir 21c is formed between the outer peripheral surface of the support shaft 21 and the inner peripheral surfaces of the pair of rollers 22. The oil reservoir 21c is a space that is continuous in the circumferential direction between the support shaft 21 and the pair of rollers 22, which face each other with a predetermined radial distance between them. The oil reservoir 21c stores lubricating oil that is supplied through a lubricating oil supply port 25g and a lubricating oil passage 25h, which will be described later. The lubricating oil stored in the oil reservoir 21c is then supplied to the entire circumferential surface and both end faces of the support shaft 21.

[0023] The bushing 23 is composed of a cylindrical portion 23a and a flange portion 23b that protrudes radially from the axial end of the cylindrical portion 23a and continues circumferentially. The cylindrical portion 23a is press-fitted into the inner peripheral surface of the roller 22. The flange portion 23b abuts against the end surface of the roller 22. The bushing 23 rotates together with the roller 22. Meanwhile, a gap 31a is formed between the outer peripheral surface of the support shaft 21 and the inner peripheral surface of the cylindrical portion 23a, large enough to allow air and lubricating oil to pass through.

[0024] The floating seal 24 is composed of a pair of ring members 24a, 24b adjacent to each other in the axial direction. The ring member 24a is press-fitted into the inner circumferential surface of the roller 22 at the axial end of the roller 22 and rotates together with the roller 22. The ring member 24b is press-fitted into a circumferential groove provided in a flange portion 25c (described later). As shown in FIG. 6, the inner circumferential surface of the floating seal 24 is in communication with the inner circumferential surface of the bushing 23 and the lubricating oil passage 25h.

[0025] The collar 25 is an example of a sealing member that seals the end of the support shaft 21. The collar 25 according to this embodiment also serves to attach the roller support structure 20 to the side frame 8. However, as long as the sealing member can seal the end of the support shaft 21, it does not have to have the role of attaching the roller support structure 20 to the side frame 8. The collar 25 mainly includes a bottom wall 25a, a cylindrical wall 25b, a flange portion 25c, and an attachment portion 25d.

[0026] The bottom wall 25a has a disk-shaped outer shape corresponding to the diameter of the support shaft 21. The cylindrical wall 25b has a cylindrical outer shape that protrudes from the outer peripheral surface of the bottom wall 25a in the thickness direction of the bottom wall 25a. The inner peripheral surface of the cylindrical wall 25b has a cylindrical shape that is slightly larger than the diameter of the support shaft 21. In other words, the bottom wall 25a and the cylindrical wall 25b are a bottomed cylindrical body with one axial end closed by the bottom wall 25a and the other axial end open.

[0027] The collar 25 is then fitted onto the end of the support shaft 21. As a result, the bottom wall 25a covers the end face of the support shaft 21 across a predetermined gap 31b in the axial direction. The cylindrical wall 25b covers the circumferential surface of the support shaft 21 across a predetermined gap 31c in the radial direction. As a result, the lubricating oil stored in the oil reservoir 21c is supplied to the gaps 31b, 31c between the support shaft 21 and the collar 25 through the inner circumferential surface of the bushing 23. In other words, the collar 25 can seal the end of the support shaft 21 where the oil film is formed (preventing leakage of the lubricating oil).

[0028] The flange portion 25c projects radially from the protruding end of the cylindrical wall 25b (the end opposite the bottom wall 25a) and is continuous in the circumferential direction. A circumferential groove that accommodates the ring member 24b of the floating seal 24 is formed in the end face of the flange portion 25c facing away from the bottom wall 25a. As shown in FIG. 6, the circumferential groove of the flange portion 25c communicates with the lubricating oil passage 25h.

[0029] The mounting portions 25d are provided at two locations on the outer peripheral surface of the cylindrical wall 25b. The mounting portions 25d are portions that are attached to the side frame 8. More specifically, the mounting portions 25d have bolt holes into which bolts (not shown) are threadedly engaged to attach the roller support structure 20 to the side frame 8. However, the number of mounting portions 25d and the method of attachment to the side frame 8 are not limited to the example described above.

[0030] A pair of cylindrical wall through-holes 25e are formed in the cylindrical wall 25b, penetrating the wall in the radial direction. The pair of cylindrical wall through-holes 25e are formed at positions symmetrical with respect to the center of the cylindrical wall 25b. The pair of cylindrical wall through-holes 25e are also formed at positions that communicate with the support shaft through-hole 21b when the collar 25 is attached to the end of the support shaft 21.

[0031] The pin 26 has a cylindrical outer shape. The pin 26 is inserted through the connected support shaft through-hole 21b and the pair of cylindrical wall through-holes 25e. This fixes the collar 25 to the support shaft 21. O-rings 27 and 28 are disposed between the outer circumferential surface of the pin 26 and the inner circumferential surfaces of the pair of cylindrical wall through-holes 25e. The O-rings 27 and 28 seal the gap between the pin 26 and each of the pair of cylindrical wall through-holes 25e. This prevents lubricating oil supplied to the end of the support shaft 21 from leaking through the cylindrical wall through-holes 25e.

[0032] An air hole 25f is formed in the bottom wall 25a, penetrating it in the thickness direction. The air hole 25f is provided, for example, in the center of the bottom wall 25a in the radial direction. A cap 29 is attached and detached to the air hole 25f. When the cap 29 is removed from the air hole 25f, the space between the spindle 21 and the collar 25 is connected to the outside of the roller support structure 20. As a result, when the collar 25 is attached to the spindle 21, the air between the spindle 21 and the collar 25 is discharged to the outside. On the other hand, when the cap 29 is attached to the air hole 25f, the space between the spindle 21 and the collar 25 is isolated from the outside of the roller support structure 20 (the air hole 25f is closed). As a result, leakage of lubricating oil supplied to the end of the spindle 21 is prevented.

[0033] The lubricating oil supply port 25g opens to the outside of the bottom wall 25a. In this embodiment, the lubricating oil supply port 25g is located off-center on the bottom wall 25a. The lubricating oil passage 25h extends axially from the lubricating oil supply port 25g through the interior of the cylindrical wall 25b. The other end of the lubricating oil passage 25h is connected to a circumferential groove in the flange portion 25c. As a result, the lubricating oil injected through the lubricating oil supply port 25g is supplied to the oil reservoir 21c through the lubricating oil passage 25h, the inner circumferential surface of the floating seal 24, and the inner circumferential surface of the bushing 23. After the lubricating oil is injected into the oil reservoir 21c, the lubricating oil supply port 25g is closed by the cap 30 (see FIG. 7). The lubricating oil supply port 25g and the lubricating oil passage 25h may be formed in only one of the two collars 25.

[0034] According to the above embodiment, the O-ring is omitted from the end of the support shaft 21, and the end of the support shaft 21 on which the oil film is formed is sealed with the collar 25, which prevents the O-ring from being damaged during assembly, causing leakage of lubricating oil. In addition, the oil film prevents rust from forming on the end of the support shaft 21, which makes it easier to disassemble the roller support structure 20 (more specifically, remove the collar 25). As a result, the maintainability of the roller support structure 20 is improved.

[0035] Furthermore, according to the above embodiment, the collar 25 for attaching the roller support structure 20 to the side frame 8 is given the function of a sealing member that seals the end of the support shaft 21, so that an increase in the number of parts of the roller support structure 20 can be suppressed compared to adding a sealing member independent of the collar 25.

[0036] However, by covering the end of the support shaft 21 with the cylindrical collar 25 with a bottom, there is no way for the internal air to escape when assembling the roller support structure 20. Therefore, according to the above embodiment, by providing the air hole 25f in the bottom wall 25a, it is possible to discharge the air between the support shaft 21 and the collar 25 to the outside of the roller support structure 20 when attaching the collar 25 to the support shaft 21. As a result, the assembly of the roller support structure 20 is improved. Note that the method for discharging the internal air when assembling the roller support structure 20 is not limited to the air hole 25f, and the air hole 25f may be omitted and the following method may be adopted.

[0037] As another example, the collar 25 may be attached to the support shaft 21 with the cap 30 removed, thereby allowing air inside the roller support structure 20 to escape through the lubricant supply port 25g. That is, the air inside the roller support structure 20 is discharged from the lubricant supply port 25g through the inner circumferential surface of the bushing 23, the inner circumferential surface of the floating seal 24, and the lubricant passage 25h. Note that when the roller support structure 20 is assembled, lubricant oil has not yet been poured into the oil reservoir 21c, so there is no need to worry about lubricant oil leaking.

[0038] As yet another example, air may be released from inside the roller support structure 20 through the cylindrical wall through-hole 25e. Furthermore, by attaching O-rings 27 and 28 after inserting the pin 26 into the support shaft through-hole 21b and the cylindrical wall through-hole 25e, air can be released from inside the roller support structure 20 even when inserting the pin 26.

[0039] Furthermore, according to the above embodiment, by disposing O-rings 27, 28 between the pin 26 and each of the pair of cylindrical wall through-holes 25e, it is possible to prevent the lubricating oil supplied to the end of the support shaft 21 from leaking through the cylindrical wall through-holes 25e. Note that, because the O-rings 27, 28 are inserted into the pair of cylindrical wall through-holes 25e from opposite radial sides, there is little possibility that the O-rings 27, 28 will be damaged, as in Patent Document 1.

[0040] Furthermore, by covering the end of the support shaft 21 with the collar 25, closing the air hole 25f with the cap 29, closing the lubricating oil supply port 25g with the cap 30, and sealing the gap between the pin 26 and each of the pair of cylindrical wall through-holes 25e with the O-rings 27 and 28, it is possible to prevent soil and dust from entering the inside of the roller support structure 20 when the hydraulic excavator 1 is in operation. As a result, it is possible to effectively prevent the support shaft 21 from rusting.

[0041] However, the method for sealing the gap between the pin 26 and each of the pair of cylindrical wall through-holes 25e is not limited to the O-rings 27 and 28. As another example, the gap between the pin 26 and each of the pair of cylindrical wall through-holes 25e may be sealed by filling a sealant between the pin 26 and each of the pair of cylindrical wall through-holes 25e. As yet another example, the gap between the pin 26 and each of the pair of cylindrical wall through-holes 25e may be sealed by press-fitting the pin 26 into the support shaft through-hole 21b and the pair of cylindrical wall through-holes 25e, which are connected to each other.

[0042] Furthermore, according to the above embodiment, the groove 21a is provided on the circumferential surface of the support shaft 21, which allows smooth movement of air inside the roller support structure 20. As a result, the assembly of the roller support structure is further improved. However, the groove 21a can be omitted.

[0043] FIG. 8 shows variations of grooves 21a and 21d provided in support shaft 21. Groove 21a shown in FIG. 8(A) is a recessed groove formed by radially recessing the circumferential surface of support shaft 21. The cross-sectional shape (radial cross section) of the recessed groove may be triangular, circular, rectangular, or a combination of these. Meanwhile, groove 21d shown in FIG. 8(B) is formed by cutting support shaft 21 along a cross section parallel to the axial direction. In this way, grooves 21a and 21d may have any configuration as long as they allow air to move in the axial direction of support shaft 21.

[0044] The above-described embodiments are merely illustrative examples of the present invention, and are not intended to limit the scope of the present invention to these embodiments. Those skilled in the art can implement the present invention in various other forms without departing from the spirit of the present invention. [Explanation of symbols]

[0045] 1: Hydraulic excavator 2: Lower running body 3: Upper rotating body 4: Front work equipment 4a: Boom 4b: Arm 4c: Bucket 4d, 4e, 4f: Hydraulic cylinder 5: Swivel frame 6: Counterweight 7: Cab 8: Side frame 10: Crawler device 11:Traction motor 12: Idora 13: Tracks 20: Roller support structure 21: Support shaft 21a,21d: Groove 21b: Support shaft through hole 21c: Oil pool 22: Laura 22a, 22b: Projection 23: Bush 23a: Cylindrical part 23b: Flange part 24: Floating seal 24a, 24b: Ring members 25: Color 25a: Bottom wall 25b: Cylinder wall 25c: Flange part 25d: Mounted part 25e: Cylinder wall through hole 25f: Air hole 25g: Lubricating oil supply port 25h: Lubricating oil passage 26: Pin 27, 28: O-ring 29,30: Cap 31a, 31b, 31c: Gap

Claims

1. A roller support structure comprising: a support shaft supported on a side frame of a work machine; and a roller rotatably supported on the support shaft and configured to guide a crawler belt wound around the side frame, the roller support structure having an oil reservoir formed between the support shaft and the roller for storing lubricating oil, a sealing member provided at each end of the support shaft, the sealing member sealing the end of the support shaft across a gap in which an oil film is formed by the lubricating oil supplied from the oil reservoir; a pin provided at each end of the support shaft to fix the sealing member to the support shaft, The support shaft has a support shaft through-hole that penetrates an end of the support shaft in a radial direction, The sealing member is a bottom wall covering an axial end surface of the support shaft; a cylindrical wall that projects from the outer periphery of the bottom wall in the axial direction of the support shaft, covers the peripheral surface of the support shaft across the gap, and has a pair of cylindrical wall through-holes that penetrate the support shaft in the radial direction; the pin is inserted through the support shaft through-hole and the pair of cylindrical wall through-holes to fix the sealing member to the support shaft; a lubricating oil supply port that opens to the outside and communicates with the gap is formed in the bottom wall of one of the sealing members provided at both ends of the support shaft, A roller support structure characterized in that the point where the lubricating oil supply port communicates with the gap is located between the pins provided at both ends of the support shaft.

2. 2. The roller support structure of claim 1, A roller support structure comprising a cap that is detachably attached to the air hole that penetrates the bottom wall and closes the air hole.

3. 2. The roller support structure of claim 1, A roller support structure comprising a pair of O-rings that seal between the pin and each of the pair of cylindrical wall through-holes.

4. 2. The roller support structure of claim 1, A roller support structure characterized in that a groove extending in the axial direction is formed on the peripheral surface of the support shaft so as to connect the oil reservoir and the end of the support shaft.

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