WO2022211613A1

WO2022211613A1 - Monorail bogie, bolster and parts thereof

Info

Publication number: WO2022211613A1
Application number: PCT/MY2022/000003
Authority: WO
Inventors: Bin Abdul Malik RIZAL EFFENDY; Bin Zahar YAN IZRUL ISHAK
Original assignee: Petra Transit Systems Sdn. Bhd.
Priority date: 2021-04-01
Filing date: 2022-04-01
Publication date: 2022-10-06

Abstract

The present invention provides a monorail bogie, bolster and parts thereof. There is also provided a bogie frame (200) for bogie (100) of monorail. The bogie frame (200) comprises a rectangular frame having a stirrup (224) mounted across a front frame piece and a rear frame piece of the rectangular frame. The rectangular frame having two side frame pieces (216, 218), each having a stabilizing wheel arm (262) extending downwardly, the stabilizing wheel arm (262) is formed on each of the side frame pieces (216,218) as a unibody unit. An end of the stabilizing wheel arm (262) further defines a stabilizing wheel mounting for receiving a stabilizing wheel assembly (500). A bolster assembly (700), a guide wheel assembly (400) and a stabilizing wheel assembly (500) are also provided.

Description

MONORAIL BOGIE, BOLSTER AND PARTS THEREOF

Field of the Invention

[0001] The present invention relates to monorail. More specifically, the present invention relates to a monorail bogie, bolster and parts thereof.

Background

[0002] Various forms of bogies for monorail vehicles are known. These bogies may be equipped with wheels fitted with pneumatic tires, or wheels which have their tread surfaces covered with solid rubber. The monorail vehicle usually travels upon a single beam track construction and is provided with at least two bogies. Typical bogies of monorail vehicles generally comprise of running wheels for running on upper surface of the track rail for supporting the vehicle, and lateral stability and guiding wheels are held in contact with sides of the beam.

[0003] However, it has been found that when monorail vehicle is running over the concrete beam especially when it travels over a curve, forces act on the vehicle body which may lead to vibrations causing discomfort to the passengers. [0004] It is therefore an object of the present invention to provide a bogie of the type referred which will overcome at least one of the above-mentioned drawbacks. The inventor believes that a need in the art still exists for a bogie that incorporates simple features and design which improve the ride quality and maintainability of the bogie. In particular, structural configurations of the bogie and suspension system of the bogie need to be improved to ensure its reliability and durability. These and other objects of the invention will appear more clearly from the following specification read in connection with the accompanying drawings. Summary

[0005] In one aspect of the present invention, there is provided a bogie frame for bogie of monorail comprises a rectangular frame having a stirrup mounted on top across a front frame piece and a rear frame piece of the rectangular frame. The rectangular frame having two side frame pieces, each having a stabilizing wheel ami extending downwardly, the stabilizing wheel ami is formed on each of the side frame pieces as a unibody unit. An end of the stabilizing wheel ami further defines a stabilizing wheel mounting for receiving a stabilizing wheel assembly.

[0006] In one embodiment, the side frame pieces are fabricated together with the stabilizing wheel ami as one piece.

[0007] In another embodiment, the stabilizing wheel ami extends from the side frame pieces (216, 218) forming a T-shaped. [0008] In a further embodiment, the front frame piece, the rear frame piece, and the two side pieces are casted as four individual pieces, wherein the four individual pieces are then welded together to form the rectangular frame. In an alternative embodiment, the bogie frame further comprises a top frame piece welded to the rectangular frame for reinforcing the rectangular frame’s structure, wherein the stirrup is welded on the rectangular frame over the top frame piece. [0009] In yet another alternative embodiment, the top frame piece comprises two suspension beds defines at two inner comers of the top frame piece.

[0010] In yet a further embodiment, a rear frame piece comprises hinge socket for hinging bolster amis thereto.

[0011] In a further embodiment, the front frame piece and the rear frame pieces comprises guide wheel brackets at distal ends of the frame pieces for hinging a guide wheel thereon.

[0012] Yet another embodiment, each stabilizing wheel mounting comprising a hinge bracket and a suspension bed.

[0013] In another aspect of the present invention, there is provided a bolster assembly for supporting a load wheel axle assembly having load wheels on a bogie frame of a monorail. The bolster assembly comprises a pair of bolster anus for supporting the load wheels. Each of the bolster ann comprises a bolster hinge end defines on one end of the bolster ann; a suspension pad adapted for mounting a suspension at the other end of the bolster ami; and a bolster pillow disposed between the bolster hinge end and the suspension pad and adapted for rotatably supporting the load wheel axle assembly on the bolster ami. The load wheel axle assembly is installed on the bogie frame via the pair of bolster am s that are hinged onto a frame piece of the bogie frame at the bolster hinge ends and further attached onto an opposing frame piece of the bogie frame via a suspension mounted on the suspension pad, thereby having an isolated bolster assembly for holding the load wheels on the bogie for monorail. [0014] In another embodiment, the bolster arm is a trailing suspension ami for supporting the load wheel axle assembly.

[0015] In yet another embodiment, the bolster arm further comprises a stiffener connecting the bolster hinge end and the suspension pad in-line.

[0016] In a further embodiment, the bolster assembly further comprises an airbag mounted on the suspension pad. [0017] In yet a further embodiment, the bolster hinge end, the suspension pad and the bolster pillow block are fabricated as discrete units.

[0018] In an alternative embodiment, the bolster pillow block coupled with a low^er piece block to form a bearing receptacle for holding bearings of the load wheel axle assembly.

[0019] In a further alternative embodiment, wherein detaching the lower piece block is sufficient to install/uninstall the load wheel axle assembly on/ffom the bolster pillow block.

[0020] In a further aspect of the present invention, there is provided a bogie comprising the aforesaid bolster assembly, wherein the bolster assembly is hinged on a bogie frame. [0021] In one embodiment thereof, the bogie comprises a bolster assembly having trailing suspension arm for holding the load wheel axle assembly. [0022] In yet a further aspect, there is provided a guide wheel assembly for a bogie of a monorail. The guide wheel assembly comprises a wheel arm having a hinge bracket defined at a proximal end; a suspension disposed on one distal end of the wheel arm; and a wheel spindle hub assembly holding a guide wheel tire, the wheel spindle hub assembly attached to the other distal end of the wheel arm. When the guide wheel assembly is hinged onto a bogie frame via the hinge bracket, the suspension is attached to the wheel ami.

[0023] In one embodiment, the wheel am is adapted with a trailing suspension ami for holding the guide wheel.

[0024] In yet a further embodiment, there is also provided a stabilizing wheel assembly for a bogie of a monorail. The stabilizing wheel assembly comprises a wheel ami having a hinge bracket defined at a proximal end; a suspension disposed on one distal end of the wheel ami; and a wheel spindle hub assembly holding a stabilizing wheel tire, the wheel spindle hub assembly attached to the other distal end of the wheel ami. When the guide wheel assembly is hinged onto a bogie frame via the hinge bracket, the suspension is attached to the wheel ami. [0025] In one embodiment, the wheel ami is adapted with a trailing suspension ami for holding the stabilizing wheel.

[0026] In yet a further aspect, there is provided a bogie comprise the aforesaid guide wheel assemblies and the stabilizing wheel assemblies. Brief Description of the Drawings

[0027] This invention will be described by way of non-limiting embodiments of the present inv ention with reference to the accompanying drawings, in which:

[0028] FIG. 1A illustrates one perspective view of a bogie assembly viewing from a gear box side in one embodiment of the present invention;

[0029] FIG. IB illustrates another perspective view of the bogie assembly of FIG. 1A;

[0030] FIG. 2A illustrates a perspective view of a bogie frame in accordance with an embodiment of the present invention; [0031] FIG. 2B illustrates an exploded view of the bogie frame of FIG. 2 A;

[0032] FIG. 3 illustrates a cross sectional view of a load wheel axle assembly in accordance with accordance with an embodiment of the present invention; [0033] FIG. 4 illustrates a perspective view of an upper guide wheel assembly in accordance with an embodiment of the present invention;

[0034] FIG. 5 illustrates a perspective view of a stabilizing wheel assembly in accordance with an embodiment of the present invention; [0035] FIG. 6 illustrates a guide wheel swing arm mechanism in accordance with an embodiment of the present invention; [0036] FIG. 7A illustrates perspective view of a bolster assembly in accordance with an embodiment of the present invention;

[0037] FIG. 7B illustrates a side view of the bolster assembly of FIG. 7A; [0038] FIG. 7C illustrates bottom view of the bolster assembly of FIG. 7A installed on a bogie frame in accordance with an embodiment of the present invention.

Detailed Description

[0039] In line with the above summary, the following description of a number of specific and alternative embodiments are provided to understand the inventive features of the present invention. It shall be apparent to one skilled in the art, however that this invention may be practiced without such specific details. Some of the details may not be described at length so as not to obscure the invention. For ease of reference, common reference numerals will be used throughout the figures when referring to the same or similar features common to the figures. [0040] An improved bogie design is provided focusing on improving the reliability and maintainability of the bogie. The design is also scalable for future projects. In particular, the present invention reduces stress levels further for the identified stress areas of the previous bogie. For high stress area, the present invention offers cast components to reduce the reliance on welding and improve manufacturability, including, guide wheel anus, gearbox mounting structure, disc brake flange, bolster arm, pillow block, etc. Further, the invention provides a new shock absorber mounting and air bag mounting to ease maintenance and improve ride quality.

[0041] FIG. 1A illustrates one perspective view of a bogie assembly (100) viewing from a gear box side in one embodiment of the present invention. FIG. IB illustrates another perspective view of the bogie assembly of FIG. 1A viewing from a brake side. The bogie assembly (100) is a straddle-beam type bogie. The bogie assembly (100) comprises a bogie frame (102), a load wheel axle assembly (104) a stabilizing wheel assembly (106) and a guide wheel assembly (108). [0042] The bogie frame (102) is generally a rectangular frame structure having a stirrup (122) and a pair of wheel ann (124) as illustrated in FIG. 2A. The stirrup (122) is disposed across the bogie frame (102) with two of its ends attached to the two opposing sides of the bogie frame (102). Towards the center of the stirrup (122), there is provided a king pin (126), which connects the car body with the bogie. The stirrup (122) is formed in an arch-shaped to receive the wheels (142) of the load wheel axle assembly (104) there below and surrounded by the bogie frame (102).

[0043] Further on the bogie frame (102), adjacent to the two side frames where the stirrup (122) is attached, it further comprises two wheel-amis (124) extended downwardly from both outer sides of the bogie frame (102) respectively. The stabilizing wheel assembly (106) is attached to the ends of wheel anns (124). The two wheel-arms (124) are formed as a unibody on the bogie frame (102). In one embodiment, the two wheel-amis are fabricated as part of the two side-frames of the bogie frame (102).

[0044] The bogie frame (102) further comprises mountings at its bottom side of four comers to support the guide wheel assembly (108).

[0045] The load wheel axle assembly (104) is mounted on the bogie frame (102) via a bolster assembly (not shown). More specifically, in one embodiment, the load wheel axle assembly (104) is adapted with a bolster assembly hinged onto the bogie frame (102). The load wheel axle assembly (104) is a single axle wheel assembly for holding the two wheels (142), and further comprises a brake assembly and a propulsion assembly disposed on both sides of the wheels (142), whereby the brake assembly and the propulsion assembly respectively provides and controls braking force and driving force to the wheels (142) operationally.

[0046] The guide wheel assembly (108) and the stabilizing wheel assembly (106) are hinged on the bogie frame (102) respective mountings and wheel arms. The guide wheel assembly (108) and the stabilizing wheel assembly (106) comprises wheels and suspensions whereby the wheels are hinged in a way to rolls on respective side surfaces of a track rail. The wheels offer a guiding and stabilizing support to the bogie on the track rail operationally.

[0047] FIG. 2B illustrates an exploded view of the bogie frame (200) in accordance with an embodiment of the present invention. The bogie frame (200) comprises a front frame piece (212), a rear frame piece (214), two side frame pieces (216), (218), a stirrup (224) and a top frame piece (222). The construct of the bogie frame (200) is constructed by attaching the two side frame pieces (216), (218) to the ends of the front frame piece (212) and the rear frame piece (214) to form a rectangular frame loop.

[0048] Once the rectangular loop is formed, the top frame piece (222) is attached thereon to reinforce the frame structure. The stirrup (224) is then attached onto the rectangular frame loop to form a bogie frame similar to that of the FIG. 2A.

[0049] Further in FIG. 2B, the front and rear frame pieces (212) and (214) are configured with wheel mountings at the two ends of each frame piece for holding a guide wheel assembly hereon. Each wheel mounting comprises a hinge bracket (242) and a suspension bed (244) for receiving a guide wheel having a suspension. The hinge bracket (242) is adapted to receive a wheel arm of the guide wheel assembly. The guide wheel assembly will be described later with more details. The suspension bed (244) is disposed adjacent to the hinge bracket for receiving the suspension of the guide wheel assembly. The two wheel mountings on each frame pieces (212) and (214) are oriented with the hinge bracket and suspension plate in an reverse manner at the two ends.

[0050] The two side frame pieces (216) and (218) are configured generally in a

T-shaped with a wheel ami (262) extended downwardly for receiving a stabilizing wheel at end thereof. In this embodiment, the side frame piece is fabricated with the wheel ami (262) as a unibody to ensure its durability under stress. The end of the wheel ami (262) defines a wheel mounting for receiving stabilizing wheel. The wheel mounting of the wheel ami (262) comprises a hinge bracket (264) and a suspension bed (268).

[0051] The front frame piece (212), the side frame piece (216), the rear frame piece (214) and the other side frame piece (218) are then connected end to end with each other in that sequence for form a rectangular frame loop. It is desired that the pieces are attached with welding.

[0052] The top frame piece (222) is adapted to attach onto the rectangular frame loop to reinforce the structure of the bogie frame (200). It is desired that the top frame piece (222) is attached onto the rectangular frame loop with welding. Further, the top frame piece (222) further comprises bolster beds (226) for receiving suspensions of the bolster assembly. In this embodiment, two bolster beds (226) are required and it is defined at the two inner comers of the top frame piece (222). [0053] The stirrup (224) is an arch mounted across the center opening of the rectangular frame loop connecting the front frame piece (212) and rear frame piece (214). The arch of the stirrup (224) and the center opening of the rectangular frame loop forms a space for receiving the load wheel assembly therein.

[0054] It is understood to a skilled person that the bogie is adapted to support the entire vehicle cabin on the track rail, which is subjected to a tremendous weight, especially on the bogie frame (200) that supports all the components driving the vehicle on the track. Further, it is also understood to a skilled person that weight distributions may van across the bogie frame (200). Accordingly, the embodiment of the present invention separates the bogie frame into different pieces and then weld together to form the whole frame. The pieces are adapted in a manner where the weld areas are moved away from the high stress area.

[0055] The bogie frame (200) can be made from welded sheet metals, metal tubes, shafts and castings. The grade of steel selected from the bogie frame may be of grade S355jR or equivalent, and SPHC. Casting parts welded to each other may comply with ASTM A 148/A 148M-05 for example. The welding on the bogie frame may be of fillet weld, bevel and/or butt weld as defined by the Welding Procedure Specification (WPS). Further, the bogie frame may put though a stress relieve process to reduce tension and compression of the frame structure due to welding. The bogie frame (200) may further be subjected to a surface protection that complies with ISO-12900. [0056] FIG. 3 illustrates a cross sectional view of a load wheel axle assembly

(300) in accordance with an embodiment of the present invention. The load wheel axle assembly (300) comprises two load wheels (302), an axle assembly (304), a disc brake assembly (306) and a shaft adapter (308). The two load wheels (302) includes a wheel hub having rims (322) for holding the wheels. The axle assembly (304) comprises a shaft extends across through the two load wheel tires (302); an axle flange (344) for securing the rims (322) on the shaft; and two bearings (314) installed on both sides of the load wheels, for rotatably holding the load wheel axle assembly (300) on a bolster. The shaft adapter (308) is installed on the shaft end of the axle assembly (304) for connecting to a driving shaft for driving the load wheels to rotate operationally. The disc brake assembly (306) is disposed on one side ( i.e. left side on FIG. 3 ) of the wheel tires (302) on the axle assembly (304) with a brake disc (362) of disc brake adapter of the disc brake assembly (306) bolted to the rim flange (344) of the axle assembly (304). With such configurations, the load wheel axle assembly (300) can be mounted on a bolster of the bogie, with a driving motor drives the shaft to rotate the two load wheels (302) and the disc brake assembly (306) operably slows or stops two load wheels when the brake disc (362) clamps.

[0057] In one embodiment, the load wheel axle assembly (300) is made from forged steel. In another embodiment, the axle flange (344) can be shrink fitted to the axle.

[0058] In one embodiment, the bearings (314) can be or a tapered roller type, or equivalent. [0059] FIG. 4 illustrates an explode view of a guide wheel assembly (400) in accordance with an embodiment of the present invention. The guide wheel assembly (400) comprises a guide wheel tire (402), a run-flat tire (404), a guide wheel rim (406), a guide wheel spindle hub assembly (408), a guide wheel arm (412) and a guide wheel suspension (414). The guide wheel tire (402) and the run-flat tire (404) are fitted around the guide wheel rim (406). The guide wheel spindle hub assembly (408) is fitted at the center of the guide wheel rim (406). The guide wheel spindle hub assembly (408) and the guide wheel suspension (414) are mounted to the guide wheel ann (412). The guide wheel ami (412) comprises a hinge bracket (422) to be hinged onto the coupling hinge of a bogie frame. The guide wheel arm (412) is configured with the hinge bracket (422) located at the proximal end and the guide wheel suspension (414) and the guide wheel spindle hub assembly (408) mounted on the two distal ends of the guide wheel ann (412).

[0060] The guide wheel spindle hub assembly (408) is adapted to hold the wlieel tire (402) to be horizontally oriented when mounted (hinged) on the bogie frame.

[0061] In one embodiment, the guide wheel arm (412) of the guide wheel assembly (400) is a trailing suspension ann configuration serving at an axle ann between the wheel and the suspension mounted thereon. Aside from the pivoting hinge, there is no additional moving parts internally on the guide wheel arm (412). The guide wheel ann (412) is relatively simple in its design and less parts to maintain.

[0062] FIG. 5 illustrates a perspective view of a stabilizing wheel assembly (500) in accordance with an embodiment of the present invention. The stabilizing wheel assembly (500) comprises a stabilizing wheel tire (502), a run-flat tire (504), a stabilizing wheel rim (506). a stabilizing wheel spindle hub assembly (508), a stabilizing wheel ann (512) and a stabilizing wheel suspension (514). The stabilizing wheel tire (502) and the run-flat tire (504) are fitted around the stabilizing wheel rim (506). The stabilizing wheel spindle hub assembly (508) is fitted at the center of the guide wheel rim (506). The stabilizing wheel spindle hub assembly (508) and the stabilizing wheel suspension (514) are mounted to the stabilizing wheel arm (512). The stabilizing wheel ami (512) comprises a hinge bracket (522) to be hinged onto a hinge bracket of a bogie frame arm. The stabilizing wheel ami (512) is configured with the hinge bracket (522) located at the proximal end and the stabilizing wheel suspension (514) and the stabilizing wheel spindle hub assembly (508) mounted on the two distal ends of the stabilizing wheel arm (512).

[0063] The stabilizing wheel spindle hub assembly (508) is adapted to hold the wheel tire (502) to be horizontally oriented relative to the stabilizing wheel arm when mounted (hinged) on the bogie frame.

[0064] In one embodiment, the stabilizing wheel arm (512) of the stabilizing wheel assembly (500) is a trailing suspension arm configuration serving at an axle ann between the wheel and the suspension mounted thereon. Aside from the pivoting hinge, there is no additional moving parts internally on the stabilizing wheel ann (512). The stabilizing wheel ann (512) is relatively simple in its design and less parts to maintain.

[0065] FIG. 6 illustrates a partial side view of the bogie (100) of FIG. 1 in accordance with an embodiment of the present invention. The partial side view shows an installation of the stabilizing wheel (162) and the guide wheel (182). More specifically, both stabilizing wheel (162) and the guide wheel (182) are hinged onto the mountings of the bogie frame and arm. As shown, the stabilizing wheel (162) and the guide wheel (182) are hinged onto the bogie in a horizontal orientation such that the wheels rolls on the side walls of the track rails. The stabilizing wheels (162) and the guide wheels (182) are operationally tiltable (602) about the hinge (604), whereby the tilt movements (602) is further limited by the suspension (606) mounted on the other distal end. The configuration of the guide wheel assembly and the stabilizing wheel assembly is to minimize the number of components.

[0066] In one embodiment, the suspension (606) can be an airbag, or any suitable air spring or air suspension system adapted to work at a maximum operating pressure of about S-10 bars or more. Further, in another embodiment, there is provided with at least a pressure gauge to monitor the air bag.

[0067] In one alternative embodiment, the wheel hub assembly (408) and (508) may comprise a bracket that offers a lateral adjustment for the guide and stabilizing wheel position during the installation.

[0068] FIG. 7A illustrates a perspective view of a bolster assembly (700) in accordance with an embodiment of the present invention. FIG. 7B illustrates side view of the bolster assembly (700) of FIG. 7A. FIG. 7C illustrates bottom view of the bolster assembly (700) installed on a bogie frame (750) in accordance with an embodiment of the present invention. For better illustrating the installations, guide wheels and stabilizing wheels are removed in FIG. 7C. [0069] The bolster assembly (700) comprises a pair of bolster arms (710) for supporting the load wheels there between. The bolster assembly (700) is generally a hinged configuration for supporting the load wheels (790) on the bogie frame (750), which offers an isolated bolster configuration on the bogie frame (750). Each of the bolster arm (710) comprises a bolster hinge end (712), a stiffener (716), a bolster pillow block (714) and a suspension pad (718). The bolster ami (710) is generally an elongated support with one end defining the bolster hinge end (712) and the other end defining the suspension pad (718). The bolster pillow block (714) is supported by two supporting legs above the elongated support for receiving and holding the load wheel axle assembly. Each supporting leg is attached to a proximal end of the bolster hinge end (712) and suspension pad (718) respectively. The suspension pad (714) is adapted to mount a suspension means, such as airbags (784) and shock absorber (782). The stiffener (716) is connected between the holster hinge end (712) and the suspension pad (718) as well as connecting across the supporting legs below the bolster pillow block (714). Accordingly, the bolster hinge end (712), the stiffener (716) and the suspension pad 718 are linked one to another in-line to form the elongated ami, and the pillow block (714) disposed above can be suspended above the elongated arm.

[0070] As shown in FIG. 7C, the bolster hinge end (712) of two such bolster amis can be hinged onto a corresponding hinge bracket (722) on one side frame piece of the bogie frame (750). The bolster ami (710) extends across the bogie frame (750) with the suspension pad (718) position beneath suspension beds (752) on an opposing side (relative to the hinged end) frame of the bogie frame (750). When assembled, the shock absorbers (782) and/or the airbags (784) are mounted between the suspension pad (718) and the suspension bed (752). [0071] In one embodiment, the bolster pillow block (714) has a droppable axle feature allowing the load wheel axle assembly to be removed easily. When coupled with the lower piece block (746), they form a bearing receptacle for receiving a bearing installed on the load wheel assembly thereon. When the lower piece block (746) is detached from the upper portion of the bolster pillow block (714), load wheel axle assembly can be “dropped” from the bolster arm (700), hence a quick release from the bogie for service and maintenance, including wheels replacements.

[0072] In one embodiment, The bolster pillow block (714) is a reversed-U structure with the lower block piece (746) attached thereto to form a shaft bracket for holding bearing of the axle assembly of the load wheels. The lower block piece (746) is removable alone (from the bolster pillow block (714)) such that the load wheel axle assembly can be install/uninstall thereon/therefrom. The lower piece block (746) can be secured to the upper portion of the bolster pillow block (714) with suitable fastener, such as bolts.

[0073] In another embodiment, the bolster assembly (700) may further include additional air reservoir for airbag comfort setting. The suspension means of the bogie is provided by the shock absorber and the airbag located on the bolster. Each airbag and shock absorber can be bolted onto the suspension pad (718) then to the bogie frame (750). Further, an airbag limiter may be fitted to allow higher operating pressure suitable for passenger sendee. The shock absorber provides damping effect while the airbags provide a secondary suspension to load wheel axle assembly. [0074] The bogie of embodiments of the present invention adopts a “trailing arm” bolster assembly (700) for mounting onto the bogie frame (750).

[0075] In one embodiment, the front pivot at the bolster hinged end (712) works in conjunction with the suspension means attaching the suspension pad (718) (at the end of the bolster arm) to further provide symmetric actuation of the load wheels (790) over the bogie frame (750).

[0076] A hinge arrangement of the bolster assembly (700) ( onto the bogie frame 750) provides the bolster with vertical movement for the secondary suspension.

[0077] The bolster pillow (714) clearing the rim of the load wheels for axle dropping process. [0078] While specific embodiments have been described and illustrated, it is understood that many changes, modifications, variations and combinations thereof could be made to the present invention without departing from the scope of the invention.

Claims

CLAIMS:

1. A bogie frame (200) for bogie (100) of monorail comprising: a rectangular frame having a stirrup (224) mounted on top across a front frame piece and a rear frame piece of the rectangular frame; wherein the rectangular frame having two side frame pieces (216, 218), each having a stabilizing wheel arm (262) extending downwardly the stabilizing wheel arm (262) is formed on each of the side frame pieces (216, 218) as a unibody unit; wherein an end of the stabilizing wheel arm (262) further defines a stabilizing wheel mounting for receiving a stabilizing wheel assembly (500).

2. The bogie frame (200) according to Claim 1 , wherein the side frame pieces (216, 218) is fabricated together with the stabilizing wheel ann (262) as one piece. 3. The bogie frame (200) according to Claim 1, wherein the stabilizing wheel ann

(262) extends from the side frame pieces (216, 218) fonning a T-shaped.

4. The bogie frame (200) according to Claim 1 , wherein the front frame piece (212), the rear frame piece (214), and the two side pieces (262) are casted as four individual pieces, wherein the four individual pieces are then welded together to fonn the rectangular frame.

5. The bogie frame (200) according to Claim 4, further comprising a top frame piece

(222) welded to the rectangular frame for reinforcing the rectangular frame^'s structure. wherein the stirrup (224) is welded on the rectangular frame over the top frame piece

(222).

6. The bogie frame (200) according to Claim 5, wherein the top frame piece (222) comprises two suspension beds (226) defines at two inner comers of the top frame piece

(222).

7. The bogie frame according to Claim 1. wherein a rear frame piece (214) comprises hinge socket for hinging bolster amis thereto.

8. The bogie frame (200) according to Claim 1, wherein the front frame piece and the rear frame pieces comprises guide wheel brackets (242) at distal ends of the frame pieces for hinging a guide wheel (162) thereon. 9. The bogie frame (200) according to Claim 1. wherein each stabilizing wheel mounting comprising a hinge bracket (264) and a suspension bed (268).

10. A bolster assembly (700) for supporting a load wheel axle assembly (300) having load wheels on a bogie frame (750) of a monorail, the bolster assembly (700) comprising: a pair of bolster amis (710) for supporting the load wheels, each of the bolster ami (710) comprises: a bolster hinge end (712) defines on one end of the bolster arm (710); a suspension pad (718) adapted for mounting a suspension at the other end of the bolster ami (710); and a bolster pillow (716) disposed between the bolster hinge end (712) and the suspension pad (718) and adapted for rotatably supporting the load wheel axle assembly (300) on the bolster arm (710); wherein load wheel axle assembly (300) is installed on the bogie frame (750) via the pair of bolster amis (710) that are hinged onto a frame piece of the bogie frame (750) at the bolster hinge ends (712) and further attached onto an opposing frame piece of the bogie frame (750) via a suspension mounted on the suspension pad (718), thereby having an isolated bolster assembly for holding the load wheels on the bogie for monorail.

11. The bolster assembly (700) according to Claim 10, where the bolster arm (710) is a trailing suspension ami for supporting the load wheel axle assembly (300).

12. The bolster assembly (700) according to Claim 10, wherein the bolster ann (710) further comprises a stiffener (716) connecting the bolster hinge end (712) and the suspension pad (718) in-line.

13. The bolster assembly (700) according to Claim 10, further comprises an airbag mounted on the suspension pad (718).

14. The bolster assembly (700) according to Claim 10, wherein the bolster hinge end (712), the suspension pad (718) and the bolster pillow block (714) are fabricated as discrete units.

15. The bolster assembly (700) according to Claim 10, wherein the bolster pillow block (714) coupled with a lower piece block (746) to form a bearing receptacle for holding bearings of the load wheel axle assembly (790).

16. The bolster assembly (700) according to Claim 15. wherein detaching the lower piece block (746) is sufficient to install/uninstall the load wheel axle assembly on/from the bolster pillow block (714).

17. A bogie (100) comprising a bolster assembly (700) according to Claim 10, wherein the bolster assembly (700) is hinged on a bogie frame.

18. The bogie (100) comprises a bolster assembly (700) having trailing suspension ami for holding the load wheel axle assembly.

19. A guide wheel assembly (400) for a bogie (100) of a monorail, the guide wheel assembly (400) comprising: a wheel ami (412) having a hinge bracket (422) defined at a proximal end; a suspension (414) disposed on one distal end of the wheel arm (412); and a wheel spindle hub assembly (408) holding a guide wheel tire (402), the wheel spindle hub assembly (408) attached to the other distal end of the wheel ami (412); wherein when the guide wheel assembly (400) is hinged onto a bogie frame via the hinge bracket (422), the suspension (414) is attached to the wheel ami (412).

20. The guide wheel assembly (400) according to Claim 19, wherein the wheel ami (412) is adapted with a trailing suspension ami for holding the guide wheel.

21. A stabilizing wheel assembly (500) for a bogie (100) of a monorail, the stabilizing wheel assembly (500) comprising: a wheel arm (512) having a hinge bracket (522) defined at a proximal end; a suspension (514) disposed on one distal end of the wheel arm (512); and a wheel spindle hub assembly (508) holding a stabilizing wheel tire (502), the wheel spindle hub assembly (508) attached to the other distal end of the wheel arm (512); wherein when the stabilizing wheel assembly (500) is hinged onto a bogie frame via the hinge bracket (524), the suspension (514) is attached to the wheel arm (512). 22. The stabilizing wheel assembly (500) according to Claim 21, wherein the wheel ami (512) is adapted with a trailing suspension ami for holding the stabilizing wheel.

23. A bogie (100) comprising: four guide wheel assemblies (400) of Claims 19 or Claims 20; a pair of stabilizing wheel assemblies (500) of Claim 21 or Claim 22.