Wet clutch, gearbox and tractor

Abstract

The utility model provides a wet clutch, a gearbox and a tractor. A wet clutch comprises a disc spring, a plurality of friction plates, a plurality of steel plates, a quick return piston, a plurality of wave springs and a wet clutch cylinder body, the disc spring, the friction plates, the steel plates, the quick return piston and the wave springs are all installed in the wet clutch cylinder body, the disc spring is connected with the quick return piston, and the wave springs are connected with the disc spring. The multiple friction plates and the multiple steel sheets are arranged at intervals, and the multiple wave springs are installed on the peripheral side walls of the multiple friction plates correspondingly.

Description

Technical Field

[0001] The utility model relates to the technical field of clutches, in particular to a wet clutch, a gearbox and a tractor. Background Art

[0002] As an agricultural machinery, the tractor has complex and changeable operating conditions, the clutch return and engagement response are slow, and there is a wet clutch drag problem. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a wet clutch, a gearbox and a tractor in view of the deficiencies of the prior art.

[0004] The utility model provides a technical solution for solving the above-mentioned technical problems as follows: a wet clutch, comprising: a disc spring, a plurality of friction plates, a plurality of steel plates, a quick return piston, a plurality of wave springs, and a wet clutch cylinder body, wherein the disc spring, the friction plate, the steel plate, the quick return piston, and the wave spring are all installed in the wet clutch cylinder body, the disc spring is connected to the quick return piston, the plurality of friction plates and the plurality of steel plates are arranged at intervals from each other, and the plurality of wave springs are respectively installed on the outer peripheral side walls of the plurality of friction plates.

[0005] The beneficial effects of the technical solution of the utility model are as follows: a wave spring is added to the outer diameter of the friction plate between the steel plates, and the wave spring will also be subjected to a certain pressure when the steel plate and the friction plate are pressed, which increases the installation space of the wave spring in the radial direction and reduces the sliding wear of the friction plate and the steel plate. When switching the clutch, the disc spring returns to the fast return piston of the wet clutch, and the wave spring separates the steel plate and the friction plate, cutting off the drag of the lubricating oil. The clutch returns and engages quickly, solves the drag problem of the wet clutch, and the clutch is separated more thoroughly, which improves the comfort of shifting. Improve the use performance, operation performance and durability of the wet clutch. The structure is compact, simple, stable and low cost.

[0006] Furthermore, the friction plate is a corrugated friction plate.

[0007] The beneficial effects of adopting the above-mentioned further technical scheme are: a stamping waveform is added to the friction plate, and a wave spring is added at the outer diameter of the friction plate between the steel plates. When the steel plates and the friction plates are pressed, the wave spring will also be subjected to a certain pressure, thereby increasing the gap between the friction plates and the steel plates. The total thickness of the friction plates and the steel plates remains unchanged, and the axial installation space of the friction plates and the steel plates is increased. The installation space of the wave spring is increased radially, thereby reducing the sliding wear of the friction plates and the steel plates.

[0008] Furthermore, the wave spring is located between two adjacent steel sheets.

[0009] The beneficial effects of adopting the above further technical solution are: adding a wave spring at the outer diameter of the friction plate between the steel plates, and the wave spring will also be subjected to a certain pressure when the steel plate and the friction plate are pressed, increasing the installation space of the wave spring in the radial direction, and reducing the sliding wear of the friction plate and the steel plate. When switching the clutch, the disc spring returns to the fast return piston of the wet clutch, and the wave spring separates the steel plate and the friction plate, cutting off the drag of the lubricating oil. The clutch returns and engages quickly, solves the drag problem of the wet clutch, and the clutch is separated more thoroughly, which improves the comfort of shifting. Improve the use performance, operation performance and durability of the wet clutch. The structure is compact, simple, stable and low cost.

[0010] Furthermore, an oil passage is provided on the quick return piston, and an oil return screw and a steel ball are provided in the oil passage on the quick return piston.

[0011] The beneficial effects of adopting the above further technical solution are: optimizing the piston structure to make the clutch return and engagement response fast, solving the drag problem of the wet clutch. When the wet clutch is engaged, the air in the pressure oil channel can be discharged through the oil return screw and the steel ball, so that the clutch can be quickly filled with oil; when the wet clutch is disengaged, part of the oil can be quickly drained through the oil return screw and the steel ball. Assisting the clutch to achieve the purpose of rapid engagement and separation.

[0012] In addition, the utility model also provides a gearbox, including a pair of wet clutches as described in any one of the above items, and also includes: a housing, an input shaft, the input shaft and a pair of wet clutches are installed in the housing, and a pair of wet clutches are sleeved on the input shaft.

[0013] The beneficial effects of adopting the technical solution of the utility model are: improving the performance, operation and durability of the tractor gearbox. The engine transmits torque to two wet clutches through the input shaft. A wave spring is added at the outer diameter of the friction plate between the steel plates. When the steel plates and the friction plates are pressed, the wave spring will also be subjected to a certain pressure, which increases the installation space of the wave spring in the radial direction and reduces the sliding wear of the friction plates and the steel plates. When switching the clutch, the disc spring returns to the fast return piston of the wet clutch, and the wave spring separates the steel plate and the friction plate to cut off the drag of the lubricating oil. The clutch returns and engages quickly, solves the drag problem of the wet clutch, and the clutch is separated more thoroughly, which improves the comfort of shifting. Improve the performance, operation and durability of the wet clutch. The structure is compact, simple, stable and low cost.

[0014] Furthermore, an oil distribution seat and an oil distribution ring are sleeved on the input shaft, the oil distribution seat is located on one side of a wet clutch, the oil distribution ring is located between a pair of wet clutches, an oil channel hole is provided on the input shaft, and the oil distribution seat and the oil distribution ring are both connected to the oil channel hole on the input shaft.

[0015] The beneficial effect of adopting the above further technical solution is that the system pressure oil passes through the oil distribution seat and the oil distribution ring, and then through the oil channel hole of the input shaft, respectively pushing the quick return piston in the wet clutch to overcome the elastic force of the disc spring.

[0016] Furthermore, a high gear driving gear, a low gear driving gear, a reverse gear driving gear, and a direct gear output gear are sleeved on the input shaft; the high gear driving gear and the low gear driving gear are respectively located on both sides of a wet clutch; the high gear driving gear and the low gear driving gear are both connected to a wet clutch via a spline; the reverse gear driving gear and the direct gear output gear are respectively located on both sides of another wet clutch; and the reverse gear driving gear is connected to another wet clutch via a spline.

[0017] The beneficial effect of adopting the above further technical solution is that the torque is transmitted to the power shift shaft through the friction force generated between multiple friction plates and multiple steel plates and then through the spline and the driving gears connected to each clutch (high gear driving gear, low gear driving gear, reverse gear driving gear).

[0018] Furthermore, a power change shaft is provided in the shell, and a high gear passive gear, a low gear passive gear, a reverse gear passive gear, and a direct gear driving gear are sleeved on the power change shaft. The high gear passive gear is meshed with the high gear driving gear, the low gear passive gear is meshed with the low gear driving gear, the reverse gear passive gear is meshed with the reverse gear driving gear, and the direct gear driving gear is meshed with the direct gear output gear.

[0019] The beneficial effect of adopting the above further technical solution is: the torque is transmitted to the direct gear output gear through the direct gear driving gear, and when the clutch connected to the direct gear output gear is engaged, the power will be output from the direct gear output gear.

[0020] Furthermore, the wet clutch cylinder body is connected to the input shaft via a spline, and a reverse idler gear is provided in the housing, and the reverse idler gear is meshed with the reverse driving gear.

[0021] The beneficial effects of adopting the above further technical solution are: the input shaft and the wet clutch cylinder body are rigidly connected through the spline. The setting of the reverse idler gear facilitates changing the final output shaft rotation direction.

[0022] In addition, the utility model also provides a tractor, comprising a gearbox as described in any one of the above items.

[0023] The beneficial effects of adopting the technical solution of the utility model are: improving the performance, operation and durability of the tractor gearbox. The engine transmits torque to two wet clutches through the input shaft. A wave spring is added at the outer diameter of the friction plate between the steel plates. When the steel plates and the friction plates are pressed, the wave spring will also be subjected to a certain pressure, which increases the installation space of the wave spring in the radial direction and reduces the sliding wear of the friction plates and the steel plates. When switching the clutch, the disc spring returns to the fast return piston of the wet clutch, and the wave spring separates the steel plate and the friction plate to cut off the drag of the lubricating oil. The clutch returns and engages quickly, solves the drag problem of the wet clutch, and the clutch is separated more thoroughly, which improves the comfort of shifting. Improve the performance, operation and durability of the wet clutch. The structure is compact, simple, stable and low cost.

[0024] Advantages of additional aspects of the present invention will be partially given in the following description, and partially become apparent from the following description, or be understood through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is one of the structural schematic diagrams of the wet clutch provided in the embodiment of the utility model.

[0026] Figure 2 This is a second structural schematic diagram of a wet clutch provided in an embodiment of the utility model.

[0027] Figure 3 The third structural schematic diagram of the wet clutch provided in the embodiment of the utility model.

[0028] Figure 4 This is a fourth structural schematic diagram of a wet clutch provided in an embodiment of the utility model.

[0029] Figure 5 This is the fifth structural schematic diagram of the wet clutch provided in the embodiment of the utility model.

[0030] Explanation of the accompanying figures: 1. Input shaft; 2. Oil distribution seat; 3. High gear driving gear; 4. Wet clutch; 5. Low gear driving gear; 6. Oil distribution ring; 7. Reverse gear driving gear; 8. Direct gear output gear; 9. High gear passive gear; 10. Power shift shaft; 11. Low gear passive gear; 12. Reverse gear passive gear; 13. Direct gear driving gear; 14. Disc spring; 15. Friction plate; 16. Steel plate; 17. Quick return piston; 17-1. Oil return screw; 17-2. Steel ball; 18. Wave spring; 19. Reverse gear idler; 20. Wet clutch cylinder; 21. Housing. DETAILED DESCRIPTION

[0031] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The embodiments given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0032] like Figures 1 to 5 As shown, an embodiment of the utility model provides a wet clutch, comprising: a disc spring 14, a plurality of friction plates 15, a plurality of steel plates 16, a quick return piston 17, a plurality of wave springs 18, and a wet clutch cylinder 20, wherein the disc spring 14, the friction plate 15, the steel plate 16, the quick return piston 17, and the wave spring 18 are all installed in the wet clutch cylinder 20, the disc spring 14 is connected to the quick return piston 17, the plurality of friction plates 15 and the plurality of steel plates 16 are spaced apart from each other, and the plurality of wave springs 18 are respectively installed on the outer peripheral side walls of the plurality of friction plates 15.

[0033] The beneficial effects of the technical solution of the utility model are as follows: a wave spring is added to the outer diameter of the friction plate between the steel plates, and the wave spring will also be subjected to a certain pressure when the steel plate and the friction plate are pressed, which increases the installation space of the wave spring in the radial direction and reduces the sliding wear of the friction plate and the steel plate. When switching the clutch, the disc spring returns to the fast return piston of the wet clutch, and the wave spring separates the steel plate and the friction plate, cutting off the drag of the lubricating oil. The clutch returns and engages quickly, solves the drag problem of the wet clutch, and the clutch is separated more thoroughly, which improves the comfort of shifting. Improve the use performance, operation performance and durability of the wet clutch. The structure is compact, simple, stable and low cost.

[0034] In order to improve the performance, operability and durability of the tractor gearbox, a wet clutch (a wet clutch) using a wave spring + friction plate + quick return piston combination is applied.

[0035] The wet clutch of wave spring + friction plate + quick return piston optimizes the structure of the friction plate and the piston on the basis of the existing wet clutch. Specifically, a stamped waveform (wave friction plate) is added to the friction plate, and a wave spring is added at the outer diameter of the friction plate between the steel plates. When the steel plates and friction plates are pressed, the wave spring will also be subjected to a certain pressure, which increases the gap between the friction plate and the steel plate. The total thickness of the friction plate and the steel plate remains unchanged, and the axial installation space of the friction plate and the steel plate is increased. The installation space of the wave spring is increased radially, and the sliding wear of the friction plate and the steel plate is reduced. The piston structure (quick return piston) is optimized to make the clutch (wet clutch) return and engagement response fast, thus solving the drag problem of the wet clutch.

[0036] like Figures 1 to 5 As shown, further, the friction plate 15 is a corrugated friction plate.

[0037] The beneficial effects of adopting the above-mentioned further technical scheme are: a stamping waveform is added to the friction plate, and a wave spring is added at the outer diameter of the friction plate between the steel plates. When the steel plates and the friction plates are pressed, the wave spring will also be subjected to a certain pressure, thereby increasing the gap between the friction plates and the steel plates. The total thickness of the friction plates and the steel plates remains unchanged, and the axial installation space of the friction plates and the steel plates is increased. The installation space of the wave spring is increased radially, thereby reducing the sliding wear of the friction plates and the steel plates.

[0038] like Figures 1 to 5 As shown, further, the wave spring 18 is located between two adjacent steel sheets 16 .

[0039] The beneficial effects of adopting the above further technical solution are: adding a wave spring at the outer diameter of the friction plate between the steel plates, and the wave spring will also be subjected to a certain pressure when the steel plate and the friction plate are pressed, increasing the installation space of the wave spring in the radial direction, and reducing the sliding wear of the friction plate and the steel plate. When switching the clutch, the disc spring returns to the fast return piston of the wet clutch, and the wave spring separates the steel plate and the friction plate, cutting off the drag of the lubricating oil. The clutch returns and engages quickly, solves the drag problem of the wet clutch, and the clutch is separated more thoroughly, which improves the comfort of shifting. Improve the use performance, operation performance and durability of the wet clutch. The structure is compact, simple, stable and low cost.

[0040] like Figures 1 to 5 As shown, further, an oil passage is provided on the quick return piston 17, and an oil return screw 17-1 and a steel ball 17-2 are provided in the oil passage on the quick return piston 17.

[0041] The beneficial effects of adopting the above further technical solution are: optimizing the piston structure to make the clutch return and engagement response fast, solving the drag problem of the wet clutch. When the wet clutch is engaged, the air in the pressure oil channel can be discharged through the oil return screw and the steel ball, so that the clutch can be quickly filled with oil; when the wet clutch is disengaged, part of the oil can be quickly drained through the oil return screw and the steel ball. Assisting the clutch to achieve the purpose of rapid engagement and separation.

[0042] like Figures 1 to 5 As shown, in addition, the utility model also provides a gearbox, including a pair of wet clutches 4 as described in any one of the above items, and also includes: a housing 21, an input shaft 1, the input shaft 1 and a pair of wet clutches are installed in the housing 21, and a pair of wet clutches are sleeved on the input shaft 1.

[0043] The beneficial effects of adopting the technical solution of the utility model are: improving the performance, operation and durability of the tractor gearbox. The engine transmits torque to two wet clutches through the input shaft. A wave spring is added at the outer diameter of the friction plate between the steel plates. When the steel plates and the friction plates are pressed, the wave spring will also be subjected to a certain pressure, which increases the installation space of the wave spring in the radial direction and reduces the sliding wear of the friction plates and the steel plates. When switching the clutch, the disc spring returns to the fast return piston of the wet clutch, and the wave spring separates the steel plate and the friction plate to cut off the drag of the lubricating oil. The clutch returns and engages quickly, solves the drag problem of the wet clutch, and the clutch is separated more thoroughly, which improves the comfort of shifting. Improve the performance, operation and durability of the wet clutch. The structure is compact, simple, stable and low cost.

[0044] like Figures 1 to 5 As shown, further, an oil distribution seat 2 and an oil distribution ring 6 are sleeved on the input shaft 1, the oil distribution seat 2 is located on one side of a wet clutch, the oil distribution ring 6 is located between a pair of wet clutches, an oil channel hole is provided on the input shaft 1, and the oil distribution seat 2 and the oil distribution ring 6 are both connected to the oil channel hole on the input shaft 1.

[0045] The beneficial effect of adopting the above further technical solution is that the system pressure oil passes through the oil distribution seat and the oil distribution ring, and then through the oil channel hole of the input shaft, respectively pushing the quick return piston in the wet clutch to overcome the elastic force of the disc spring.

[0046] like Figures 1 to 5 As shown, further, a high gear driving gear 3, a low gear driving gear 5, a reverse gear driving gear 7, and a direct gear output gear 8 are sleeved on the input shaft 1, the high gear driving gear 3 and the low gear driving gear 5 are respectively located on both sides of a wet clutch, the high gear driving gear 3 and the low gear driving gear 5 are both connected to a wet clutch through a spline, the reverse gear driving gear 7 and the direct gear output gear 8 are respectively located on both sides of another wet clutch, and the reverse gear driving gear 7 is connected to another wet clutch through a spline.

[0047] The beneficial effect of adopting the above further technical solution is that the torque is transmitted to the power shift shaft through the friction force generated between multiple friction plates and multiple steel plates and then through the spline and the driving gears connected to each clutch (high gear driving gear, low gear driving gear, reverse gear driving gear).

[0048] like Figures 1 to 5As shown, further, a power change shaft 10 is provided in the housing 21, and a high gear passive gear 9, a low gear passive gear 11, a reverse gear passive gear 12, and a direct gear driving gear 13 are sleeved on the power change shaft 10. The high gear passive gear 9 is meshed with the high gear driving gear 3, the low gear passive gear 11 is meshed with the low gear driving gear 5, the reverse gear passive gear 12 is meshed with the reverse gear driving gear 7, and the direct gear driving gear 13 is meshed with the direct gear output gear 8.

[0049] The beneficial effect of adopting the above further technical solution is: the torque is transmitted to the direct gear output gear through the direct gear driving gear, and when the clutch connected to the direct gear output gear is engaged, the power will be output from the direct gear output gear.

[0050] like Figures 1 to 5 As shown, further, the wet clutch cylinder body 20 is connected to the input shaft 1 through a spline, and a reverse idler gear 19 is provided in the housing 21 , and the reverse idler gear 19 is meshed with the reverse driving gear 7 .

[0051] The beneficial effects of adopting the above further technical solution are: the input shaft and the wet clutch cylinder body are rigidly connected through the spline. The setting of the reverse idler gear facilitates changing the final output shaft rotation direction.

[0052] The embodiment of the utility model provides a wet clutch, which can be a structure used in combination of a wave spring + friction plate + quick return piston, thereby solving the problem of large drag of the wet clutch and solving the problem of slow return and engagement response of the clutch.

[0053] like Figures 1 to 5As shown, the wet clutch structure (wet clutch) used in the tractor gearbox wave spring + friction plate combination includes: the engine transmits torque to two wet clutches 4 through the input shaft 1 (the input shaft 1 and the wet clutch cylinder 20 are rigidly connected through splines); the system pressure oil passes through the oil distribution seat 2 and the oil distribution ring 6, and then passes through the oil channel hole of the input shaft 1, and pushes the quick return piston 17 in the wet clutch 4 to overcome the elastic force of the disc spring 14 (the quick return piston 17 can move axially on the wet clutch cylinder 20, and only pushes one piston to move each time). , to combine different gears), and also compress the wave spring 18, and finally press the multiple friction plates 15 and the multiple steel plates 16; the friction force generated between the multiple friction plates 15 and the multiple steel plates 16 is then transmitted to the power change shaft 10 through the spline and the driving gears connected to each clutch (high gear driving gear 3, low gear driving gear 5, reverse gear driving gear 7), and then through the direct gear driving gear 13, the torque is transmitted to the direct gear output gear 8; when the clutch connected to the direct gear output gear 8 is engaged, the power will be output from the direct gear output gear 8. Only one wet clutch can be engaged at a time. When switching the clutch, the disc spring 14 returns to the quick return piston 17 of the corresponding wet clutch, and the wave spring 18 separates the steel plate and the friction plate, cutting off the drag of the lubricating oil. When the wet clutch is engaged, the air in the pressure oil channel can be discharged through the oil return screw 17-1 and the steel ball 17-2, so that the clutch is quickly filled with oil; when the wet clutch is separated, part of the oil can be quickly drained through the oil return screw 17-1 and the steel ball 17-2. Assist the clutch to achieve quick engagement and separation.

[0054] Solve the drag problem of wet clutch, reduce the sliding wear of friction plate and steel plate, make the gear shift response faster, the clutch separation more thorough, and improve the comfort of gear shift. The structure is compact, simple, more stable and low cost.

[0055] In addition, the utility model also provides a tractor, comprising a gearbox as described in any one of the above items.

[0056] The beneficial effects of adopting the technical solution of the utility model are: improving the performance, operation and durability of the tractor gearbox. The engine transmits torque to two wet clutches through the input shaft. A wave spring is added at the outer diameter of the friction plate between the steel plates. When the steel plates and the friction plates are pressed, the wave spring will also be subjected to a certain pressure, which increases the installation space of the wave spring in the radial direction and reduces the sliding wear of the friction plates and the steel plates. When switching the clutch, the disc spring returns to the fast return piston of the wet clutch, and the wave spring separates the steel plate and the friction plate to cut off the drag of the lubricating oil. The clutch returns and engages quickly, solves the drag problem of the wet clutch, and the clutch is separated more thoroughly, which improves the comfort of shifting. Improve the performance, operation and durability of the wet clutch. The structure is compact, simple, stable and low cost.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A wet clutch, characterized in that: include: A disc spring (14), a plurality of friction plates (15), a plurality of steel plates (16), a quick return piston (17), a plurality of wave springs (18), and a wet clutch cylinder (20); the disc spring (14), the friction plates (15), the steel plates (16), the quick return piston (17), and the wave spring (18) are all installed in the wet clutch cylinder (20); the disc spring (14) is connected to the quick return piston (17); the plurality of friction plates (15) and the plurality of steel plates (16) are arranged at intervals from each other; the plurality of wave springs (18) are respectively installed on the outer peripheral side walls of the plurality of friction plates (15); an oil channel is provided on the quick return piston (17); an oil return screw (17-1) and a steel ball (17-2) are provided in the oil channel on the quick return piston (17).

2. A wet clutch according to claim 1, characterized in that: The friction plate (15) is a corrugated friction plate.

3. A wet clutch according to claim 1, characterized in that: The wave spring (18) is located between two adjacent steel sheets (16).

4. A gearbox, characterized in that: It comprises a pair of wet clutches as described in any one of claims 1 to 3, and also comprises: a housing (21), an input shaft (1), the input shaft (1) and the pair of wet clutches are both mounted in the housing (21), and the pair of wet clutches are sleeved on the input shaft (1).

5. A gearbox according to claim 4, characterized in that: The input shaft (1) is sleeved with an oil distribution seat (2) and an oil distribution ring (6); the oil distribution seat (2) is located on one side of a wet clutch; the oil distribution ring (6) is located between a pair of wet clutches; an oil passage hole is provided on the input shaft (1); the oil distribution seat (2) and the oil distribution ring (6) are both connected to the oil passage hole on the input shaft (1).

6. A gearbox according to claim 4, characterized in that: The input shaft (1) is sleeved with a high gear driving gear (3), a low gear driving gear (5), a reverse gear driving gear (7), and a direct gear output gear (8); the high gear driving gear (3) and the low gear driving gear (5) are respectively located on both sides of a wet clutch; the high gear driving gear (3) and the low gear driving gear (5) are both connected to a wet clutch via a spline; the reverse gear driving gear (7) and the direct gear output gear (8) are respectively located on both sides of another wet clutch; the reverse gear driving gear (7) is connected to another wet clutch via a spline.

7. A gearbox according to claim 6, characterized in that: A power shift shaft (10) is provided in the housing (21). A high gear passive gear (9), a low gear passive gear (11), a reverse gear passive gear (12), and a direct gear driving gear (13) are sleeved on the power shift shaft (10). The high gear passive gear (9) is meshed with the high gear driving gear (3), the low gear passive gear (11) is meshed with the low gear driving gear (5), the reverse gear passive gear (12) is meshed with the reverse gear driving gear (7), and the direct gear driving gear (13) is meshed with the direct gear output gear (8).

8. A gearbox according to claim 7, characterized in that: The wet clutch cylinder body (20) is connected to the input shaft (1) via a spline, and a reverse gear idler wheel (19) is arranged in the housing (21), and the reverse gear idler wheel (19) is meshed with the reverse gear driving gear (7).

9. A tractor, characterized in that: A gearbox comprising any one of claims 4 to 8.

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