SNOWMOBILE TRANSMISSION

Abstract

Snowmobile transmission, including a housing with a cover, an input shaft and an output shaft arranged inside the housing, and a chain transmission drive including a chain connecting a drive sprocket arranged on the input shaft to a driven sprocket arranged on the output shaft, a reverse gear axle about which a reverse gear sprocket freely rotates also arranged inside the housing, the reverse gear sprocket engaging with the chain, and a reverse gear engaging with a movable gear arranged on a grooved sleeve of the input shaft, which is movable by tilting an inner switching fork and being driven by an axle with a lever, an adjusting rod, an outer switching fork, wherein rotation of the outer switching fork is restricted by a removable sector attached to the housing cover, and an adjusting screw arranged on the housing, abutting against a support sleeve and fixed by a cotter pin.

Claims

1. A snowmobile transmission comprising a chain transmission housing with a cover. an input shaft and output shaft arranged inside the housing, as well as a chain transmission drive, the chain transmission drive including a chain that connects a drive sprocket arranged on the input shaft to a driven sprocket arranged on the output shaft, an inner switching fork and an outer switching fork, an adjusting rod, a reverse gear axle about which a reverse gear sprocket freely rotates being also arranged inside the housing, the reverse gear sprocket engaging with the chain, and a reverse gear which engages with a movable gear arranged on a grooved sleeve of the input shaft, which is movable by virtue of tilting the inner switching fork and being driven by means of an axle with a lever, wherein rotation of the outer switching fork is restricted by means of a removable sector which is fixed to the housing cover; and an adjusting screw, which abuts against a support sleeve and is fixed by means of a cotter pin, is arranged on the housing.

2. The snowmobile transmission of claim 1, wherein a tensioner support is arranged on a chain tensioner, which abuts against the housing cover.

3. The snowmobile transmission of claim 2, wherein a steel roller is arranged on the chain tensioner.

4. The snowmobile transmission of claim 1, wherein additional guides for the chain, which function both in a forward gear mode and a reverse gear mode, are arranged inside the housing.

5. The snowmobile transmission of claim 1, wherein a seat is provided on the housing for installing a removable support sleeve designed for the adjusting screw to abut against removable support sleeve.

6. The snowmobile transmission of claim 1, wherein a marking opening is provided in the chain transmission housing, the marking opening being intended for installing a repair support screw with a sealing ring.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0080] The claimed structure is explained using the following drawings:

[0081] FIG. 1 General view of the transmission;

[0082] FIG. 2 Right-side view of the assembled transmission without the chain transmission housing cover;

[0083] FIG. 3 Right-side view of the assembled chain transmission housing without its cover;

[0084] FIG. 4 Assembled chain transmission housing;

[0085] FIG. 5 Right-side view of the assembled housing cover;

[0086] FIG. 6 Left-side view of the assembled housing cover;

[0087] FIG. 7 Assembled chain tensioning system;

[0088] FIG. 8 Exploded view of the chain tensioning system;

[0089] FIG. 9 Exploded view of the chain tensioner;

[0090] FIG. 10 Left-side oblique view of the assembled chain transmission housing;

[0091] FIG. 11 Right-side view of the assembled chain transmission housing; and

[0092] FIG. 12 Front oblique view of the assembled transmission.

DETAILED DESCRIPTION

[0093] The snowmobile transmission includes a chain transmission housing 1 having a chain transmission housing cover 2, as well as an input shaft 3 and an output shaft 4 arranged within the housing 1, a spline coupler 47 with a drive sprocket 42 is arranged on the input shaft 3 via a spline coupling, and a driven sprocket 41 is arranged on the output shaft 4 via a spline coupling, wherein the sprockets 41 and 42 are connected by means of a chain 38.

[0094] The input shaft 3 is arranged inside the housing by means of a bearing 24, and the sealing of the housing 1 at the opening for the input shaft 3 is provided by means of a lip sealing 34. The output shaft 4 is arranged inside the housing 1 by means of a bearing 25, and the housing is sealed by a lip sealing 35. The bearings 24 and 25 are arranged in recesses of the housing 1 and fixed therein by means of locking rings 28 and 29, respectively.

[0095] Besides, the driven sprocket is fixed to the driven shaft by a locking ring 46. Inside the housing, the spline coupler 47 is provided, which is arranged on the spline coupling of the input shaft 3. As such, the drive sprocket 42 is arranged on a cylindrical surface by means of a needle bearing from the inside of the spline coupler 47 and is fixed by means of a locking ring. The spline coupler 47 is fixed on the input shaft 3 by means of a bolt 56. Besides, the rear 18 and front 20 chain guides are fixed by means of cotter pins inside the housing 1 using brackets 19 and 21, respectively, by means of screws. Besides, an adjusting screw 17 is provided in the through opening of the housing 1 and in the shaped cutout, which abuts in the front part against the support sleeve 36. A tensioner assembly 57 is arranged in the shaped recess of the housing 1 and on the adjusting screw 17. A sealing ring 52 for the housing 1 is arranged in a groove on the adjusting screw. A locking cotter pin 27 is arranged in one of the openings of the adjusting screw 17 and in the corresponding cutout of the housing 1 on the left side. As such, the tensioner assembly 57 consists of a tensioner 14, a sliding support washer 49, a tensioner roller 16, a roller bearing 54, a locking ring 53, a locking ring 55, a thrust washer 50, a tensioner support 15, and a countersunk screw 51.

[0096] Besides, a reverse gear axle 22 is arranged inside the housing 1, on which a thrust sleeve 23 is mounted and a reverse gear sprocket 43 is rotated by means of a needle bearing, also interacting with the chain 38, and a reverse gear 40, which interacts with a movable gear 39 arranged on the input shaft 3.

[0097] A spacing washer 76 is arranged on the reverse gear axle 22 at the right end of the reverse gear.

[0098] Besides, two pins 30 are arranged in the housing 1, along the axis of which the housing cover 2 is docked onto the housing 1. As such, the housing cover 2 also covers the tensioner support 15 with its shaped recess. Besides, the housing cover 2 is mounted on the reverse gear axle 22, and the housing cover 2 contacts the spacing washer 76 with its inner protrusion. A sealing cord 37 is arranged in the groove of the housing 1 between the latter and the housing cover 2.

[0099] The inner switching fork 68 is arranged inside a recess in the housing cover 2, the former being fixed by spring pins 70 on the axle of the lever 64, wherein the lever with the axle 64 is, in its turn, inserted into a through and blind opening in the housing cover 2. Copper spacing rings 71 are arranged between the housing cover 2 and the inner switching fork 68. As such, cylindrical hardened one-piece pins 69 are arranged in both eyelets of the inner switching fork. On the outside, the switching sector 59 is arranged on top of the housing cover 2, which is fixed in the eyelets of the housing cover 2 by means of two screws 65. An outer switching fork 61 is arranged in the cutout of the sector 59, the former being fixed with an axial screw 60. In the housing cover 2, an outer switching fork 61 and a lever with an axle 64 are coupled to each other using a standard adjusting rod 63 by means of screws 66 and 65.

[0100] In the upper part of the housing cover 2, a filling opening cap 58 with a transmission ventilation hose inserted into it is arranged. Besides, a check plug 67 with a sealing washer is arranged in the lower part of the housing cover 2. A reverse limit switch 62 is arranged on the switching sector by means of screws 72 and nuts 73.

[0101] The housing cover 2 is fixed to the housing 1 by means of ten units of bolts.

[0102] On the right side of the housing 1, gear shift lever mechanism support bracket with the gearshift lever 8 and the lever 7 with its drive mechanism assembly on the bracket are fixed to the two eyelets by means of bolts.

[0103] The hose 11 is fixed to the snowmobile using three brackets 12.

[0104] When the gearshift lever 7 is moved from the front position in (FIG. 2) to the rear position until it stops (in FIG. 1), the effect is transmitted from the lever 7 to the outer switching fork 61 by means of drive rods and levers of the gearshift lever 7 mechanism, part of which are fixed to the support bracket 8 and have a specific kinematic scheme for transmission of the effect. The outer switching fork 61 rotates within the sector 59 and is fixed in the second extreme position after passing the intermediate apex of its trajectory, which allows a short reverse movement of the inner fork 68 to fix it and restrict the compression motion of a pullback spring, which is arranged in the recess of the movable gear 39. When the fork 61 turns, the standard adjusting rod 63 attached to it moves, wherein the lever connected to it rotates with the axle 64. By turning the lever with the axle 64, the inner switching fork 68 also turns due to its fixation on the axle 64 by means of spring pins 70. The fork 68 moves the movable reverse gear 39 to the right along the spline coupling on the spline coupler 47 by means of two cylindrical hardened one-piece pins 69. At this time, the spike-groove elements of the movable gear 39 and the drive sprocket 42 disengage. The drive sprocket 42 continues to rotate freely about the spline coupler 47 by means of a needle bearing and be engaged with the chain 38, and the movable gear 39 enters into a gear engagement with the reverse gear 40. The gear 40 is engaged with the reverse gear sprocket 43 by means of the spike-groove elements. The reverse gear sprocket 43 is in continuous engagement with the drive chain 38. The torque from the input shaft 3 is transmitted to the spline coupler 47, then to the movable gear 39, then to the reverse gear 40, then to the reverse gear sprocket 43, then to the drive chain 38, then to the driven sprocket 41 and, by means of the spline coupling, to the output shaft 4, then to the left 6 and right 5 track drive sprockets by means of a mounting seat which has a profiled outline. When the gearshift lever 7 is again moved forward until it stops upon the sector 59 by means of the outer fork 61, the operations take place in a reverse sequence, and the front gear is switched on.

[0105] A chain tensioner 14 is arranged in the housing 1, the former being provided with a tensioner adjusting screw 17, wherein a steel tensioner roller 16 and a steel tensioner support 15, which abuts against the housing cover 2, are arranged on the chain tensioner 14 on a bearing 54.

[0106] Guides 18 and 20 are also arranged on the chain transmission housing 1, which are intended for supporting the chain 38.

[0107] The claimed structure operates as follows:

[0108] In snowmobile transmission, torque is transmitted from the input shaft 3 to the output shaft 4, and its amount is transformed depending on the gear ratio used to propel the snowmobile, or the direction of rotation of the output shaft 4 is changed depending on the selected forward or reverse gear so as to change the travel direction of the snowmobile. By means of axle spacing between the input shaft 3 and output shaft 4, which is in the range of 291.1 to 291.2 mm, a drive chain 38 is used that has a smaller number of links and a shorter length, which significantly reduces the oscillations and moment of inertia of the chain, thereby increasing the reliability and extending the service life of the entire transmission.

[0109] The tensioning system of the drive chain 38 provides for precise adjustment of the position of the chain tensioner 14 with a steel roller 16 arranged thereon. By using a rotating steel roller 16 on a bearing, the rolling of the roller 16 of the chain tensioner 14 along the reverse surface of the chain 38 is ensured (and not only sliding friction, as in the closest prior art), which extends the service life, improves the reliability and maintainability of the chain tensioner system.

[0110] An opening is provided in the outer cylindrical surface of the roller 16, which leads to the inner groove of the roller 16 and further to an opening in the outer cage of the bearing 54. These openings enable the lubrication of the bearing 54 of the roller 16. Besides, special openings in the support washer 49 and thrust washer 50 provide for the circulation of lubricant inside the bearing. This also increases the service life and reliability of the entire structure.

[0111] By virtue of said axle spacing, the described chain tensioning system and its arrangement, sagging of the chain 38 is prevented, which contributes to increased angular coverage of the drive sprocket 42, the driven sprocket 41 and the reverse gear sprocket 43 by the chain. This ensures reliable contact between the teeth of the sprockets 41, 42 and 43 and the chain 38 and increases the number of teeth simultaneously engaged with the chain 38. Also, by virtue of this, amplitude of oscillations of individual sections of the chain is reduced. This increases the reliability of the entire structure.

[0112] The chain tensioner 14 moves within the recess of the chain transmission housing 1 along the adjusting screw 17 by virtue of its rotation. The chain tensioner 14 is arranged such that the beveled part of its axle is directed upwards within the housing 1. Clockwise rotation of the adjusting screw 17 causes the tensioner to move backwards, and the tension of the drive chain 38 is increased. Counterclockwise rotation of the adjusting screw 17 causes the tensioner 14 to move forward, and the chain tension is reduced. The adjusting screw 17 is locked in the desired angular position inside the housing 1 by means of a locking cotter pin 27. The locking cotter pin 27 further prevents the axial movement of the screw backwards from the housing 1. The adjusting screw 17 has two cylindrical support surfaces, one within the housing 1 and the other one within the support sleeve 36, which, at the same time, are sliding surfaces. The through opening for the adjusting screw 17 in the chain transmission housing 1 is sealed by means of a sealing ring 52. The sealing ring 52 is arranged and positioned in a groove which is located in the rear part of the screw 17. The adjusting screw 17 can be fixed within the housing 1 after every one-fourth of its turn by the cotter pin 27 mounted in one of the two openings in the screw 17. For this purpose, one of the two slots on the inside of the housing 1 is used. The adjusting screw 17 may be rotated using a 5 mm hex key, to do it, one has to insert the hex key into a hexagonal recess on the rear end of the screw 17, after having removed the cotter pin 27. When adjusting the tension of the chain 38, it is necessary to maintain the position of the adjusting screw 17 by keeping it from moving outwards from the housing 1. The support sleeve 36 for the adjusting screw 17 is installed in a blind opening in the front wall of the housing 1 recess for the tensioner 14. In the housing 1, this blind opening provides a seat for the sleeve 36 and enables its removal. Thus, the adjusting screw 17 does not cause wear and tear in the housing 1 by its front part, since it only contacts the support sleeve. This increases the reliability and maintainability of the structure.

[0113] When moving backwards, the tensioner 14 places the roller 16 in contact with the drive chain 38 by adjusting its position by rotating the adjusting screw 17. When the chain 38 moves and the position of the tensioner 14 was adjusted, the roller 16 rotates around the axis of the tensioner 14 by means of the needle bearing 54. As such, when the chain 38 moves, the rotating roller 16 both rolls and slides along the outer side of the drive chain. Lubricant flows from the outer cylindrical surface of the roller 16 to its bearing.

[0114] The roller 16 freely rotates about the tensioner 14 by virtue of the presence of the bearing and other structural elements.

[0115] When the tension of the drive chain 38 is adjusted, the tensioner 14 slides with its upper and lower faces within the recess along the inclined upper and lower horizontal faces in the chain transmission housing 1, and the vertical faces of the tensioner flange 14 slide along the faces of the two protrusions above and below the recess in the housing 1. As such, the tensioner 14 further slides with its horizontal rounded edges against roundings of the support 15 inside the recess along the edges of the housing cover 2 of the chain transmission. The tensioner 14 assembly has five support surfaces and sliding surfaces: two horizontally inclined planes within the housing 1, one vertical plane in the housing 1, two horizontal and inclined ones in the chain transmission housing 2 cover, as well as one additional support on the thread of the adjusting screw 17.

[0116] That is, the tensioner support 15, which rests against the housing cover 2, a second support point for the tensioner appears in the transmission. This also increases the service life and reliability of the chain tensioning system structure and the transmission as a whole.

[0117] The rear chain guide 18, aside from defining the movement trajectory of the chain 38 within a defined area and reducing the amplitude of chain oscillations, enables the defining of minimum pre-tension of the rear portion of the chain. The front chain guide 20, aside from defining the movement trajectory of the chain with reduced tension and reducing the amplitude of its oscillations, enables the maintaining of the necessary engagement of the chain 38 with the reverse gear sprocket 43 while reducing the chain tension. The guides 18 and 20 for the drive chain 38 function both when forward gear and when reverse gear is selected. By using the guides 18 and 20 of the chain 38, stability of the engagement between the chain and the sprockets 41, 42, 43 is increased, and thus reliability is enhanced. With the cotter pin 27 installed, the positions of the adjusting screw 17 and the tensioner 14 are fixed. As such, the roller 16 is able to rotate.

[0118] A blind marking starting opening is provided in the housing 1 for drilling and threading a M14X1.5 thread for mounting a repair support screw 77 with a blind support opening and a sealing ring instead of the support sleeve 36 for the adjusting screw 17.

[0119] This is provided for the case where the support sleeve 36 of the adjusting screw 17 and the seat for the latter in the housing 1 are worn out. This increases the maintainability of the housing 1.

[0120] When the gearshift lever 7 is moved from the front position in (FIG. 2) to the rear position until it stops (in FIG. 1), the effect is transmitted from the lever 7 to the outer switching fork 61 by means of drive rods and levers of the gearshift lever 7 mechanism, part of which are fixed to the support bracket 8 and have a specific kinematic scheme for transmission of the effect. The outer switching fork 61 rotates within the sector 59. Use of the sector 59 as a removable part increases the service life and maintainability of the structure. The outer fork 61 is fixed in the second extreme position after passing the intermediate apex of its trajectory, which allows a short reverse movement of the inner fork 68 to fix it and restrict the compression motion of the pullback spring 74, which is located in the recess of the movable gear 39. When the fork 61 turns, the standard adjusting rod 63 attached to it moves, wherein the lever connected to it rotates with the axle 64. By turning the lever with the axle 64, the inner switching fork 68 also turns due to its fixation on the axle 64 by means of spring pins 70.

[0121] The increased wall thickness of the outer 61 and inner forks 68, ranging from 4.9 to 5.1 mm for the inner fork and from 7.85 to 8 mm for the outer fork and the use of cylindrical hardened one-piece pins 69 leads to an increase in service life, connection reliability and maintainability of the transmission unit.

[0122] The fork 68 moves the movable reverse gear 39 to the right along the spline coupling on the spline coupler 47 by means of two cylindrical hardened one-piece pins 69. At this time, the spike-groove elements of the movable gear 39 and the drive sprocket 42 disengage. The drive sprocket 42 continues to rotate freely about the spline coupler 47 by means of a needle bearing and be engaged with the chain 38, and the movable gear 39 enters into a gear engagement with the reverse gear 40. The gear 40 is engaged with the reverse gear sprocket 43 by means of the spike-groove elements. The reverse gear sprocket 43 is in continuous engagement with the drive chain 38. The torque from the input shaft 3 is transmitted to the spline coupler 47, then to the movable gear 39, then to the reverse gear 40, then to the reverse gear sprocket 43, then to the drive chain 38, then to the driven sprocket 41 and, by means of the spline coupling, to the output shaft 4, then to the left 6 and right 5 track drive sprockets by means of a mounting seat which has a profiled outline. When the gearshift lever 7 is again moved forward until it stops upon the sector 59 by means of the outer fork 61, the operations take place in a reverse sequence, and the front gear is switched on.

LIST OF REFERENCE SIGNS

[0123] 1. Chain transmission housing; [0124] 2. Chain transmission housing cover; [0125] 3. Input shaft; [0126] 4. Output shaft; [0127] 5. Right track drive sprocket; [0128] 6. Left track drive sprocket; [0129] 7. Gear shift lever; [0130] 8. Gearshift lever mechanism support bracket; [0131] 9. Support part of the brake caliper bracket; [0132] 10. Base plate of the input shaft bearing; [0133] 11. Transmission ventilation hose; [0134] 12. Fixing bracket; [0135] 13. Plug (FIG. 12); [0136] 14. Chain tensioner; [0137] 15. Tensioner support; [0138] 16. Tensioner roller; [0139] 17. Tensioner adjusting screw; [0140] 18. Rear chain guide; [0141] 19. Rear guide bracket; [0142] 20. Front chain guide; [0143] 21. Front guide bracket; [0144] 22. Reverse axle; [0145] 23. Thrust sleeve on the axle (FIG. 11); [0146] 24. Input shaft bearing (FIG. 11); [0147] 25. Output shaft bearing (FIG. 11); [0148] 26. Drain screw; [0149] 27. Locking cotter pin; [0150] 28. Input shaft bearing locking ring (FIG. 11); [0151] 29. Output shaft bearing locking ring (FIG. 11); [0152] 30. Pin; [0153] 31. Cylinder head screw; [0154] 32. Spherical head screw; [0155] 33. Cotter pin; [0156] 34. Input shaft lip sealing (FIG. 10); [0157] 35. Output shaft lip sealing (FIG. 10); [0158] 36. Adjusting screw support sleeve; [0159] 37. Sealing between the chain transmission housing and the cover; [0160] 38. Chain; [0161] 39. Movable reverse gear; [0162] 40. Reverse gear wheel; [0163] 41. Driven sprocket of the chain transmission; [0164] 42. Drive sprocket of the chain transmission; [0165] 43. Reverse gear sprocket; [0166] 44. Drain screw sealing washer; [0167] 45. Output shaft plug; [0168] 46. Locking ring of the output shaft sprocket; [0169] 47. Spline coupler; [0170] 48. Mounting bracket to the snowmobile frame; [0171] 49. Sliding support washer; [0172] 50. Thrust washer; [0173] 51. Countersunk screw; [0174] 52. Sealing ring; [0175] 53. Bearing locking ring (FIG. 9); [0176] 54. Roller bearing (FIG. 9); [0177] 55. Locking ring; [0178] 56. Spline coupling mounting bolt; [0179] 57. Tensioner assembly; [0180] 58. Filler cap; [0181] 59. Switching sector; [0182] 60. Axial screw; [0183] 61. Outer switching fork; [0184] 62. Reverse limit switch; [0185] 63. Standard adjusting rod; [0186] 64. Lever with axle; [0187] 65. Screw; [0188] 66. Screw; [0189] 67. Check plug; [0190] 68. Inner switching fork; [0191] 69. Cylindrical hardened one-piece pin; [0192] 70. Spring pin; [0193] 71. Copper spacer ring; [0194] 72. Screw (FIG. 5); [0195] 73. Nut (FIG. 6); [0196] 74. Pullback spring; [0197] 75. Locking ring; [0198] 76. Spacer washer.