Multi-gear high-temperature-resistant gearbox of medium-high horsepower tractor
By placing the breather port on the rear housing of the gearbox in the medium-to-high horsepower tractor gearbox, and setting up an oil baffle channel and throttle hole, along with a baffle plate, the technical problems of oil leakage and breathing in the gearbox were solved. This achieved efficient lubrication and high-temperature resistance of the gearbox, while reducing costs and gear losses.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-28
- Publication Date
- 2026-04-07
AI Technical Summary
Existing medium and high horsepower tractor gearboxes suffer from problems such as poor gear bearing lubrication, lubricating oil spillage, oil churning loss, increased air pressure due to temperature rise, and oil leakage. In particular, when plowing on sloping land or below the bank, the gearbox has oil on one side and oil shortage on the other. Furthermore, the arrangement of the crawler gear and four-wheel drive gears is unreasonable, resulting in complex structure and high cost.
The vent is located on the rear housing, with an oil baffle channel and throttle hole. A partition separates the gear sets, and the creep gear set is located on the rear housing to reduce lubricating oil splashing and churning loss. An oil baffle is designed to suppress oil mist diffusion, and the gear layout is optimized to reduce speed and frequency of use.
It effectively avoids high-temperature oil leakage in the transmission, ensures pressure relief and venting functions, reduces costs, minimizes gear oil churning losses and oil mist diffusion, and improves the transmission's high-temperature resistance and cooling performance.
Smart Images
Figure CN121803618A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of tractor gearbox technology, and is a multi-gear high-temperature resistant gearbox for medium and high horsepower tractors. Background Technology
[0002] Currently, there are two lubrication methods for medium and high horsepower tractor gearboxes in China: lubrication by splashing lubricating oil through the rotation of gears inside the gearbox and lubrication by forced injection of lubricating oil through an external gear pump. These methods have some drawbacks. On the one hand, while lubrication by splashing lubricating oil through the rotation of gears inside the gearbox is simple in structure and low in cost, it is prone to causing poor lubrication and burnout of the gear bearings inside the gearbox. On the other hand, with lubrication by splashing lubricating oil through the rotation of gears inside the gearbox, the breather opening on the gearbox cover lacks an oil-blocking structure, allowing lubricating oil to splash and form an oil film on the breather opening or block it, causing gearbox oil to overflow. Therefore, the existing technology has the following shortcomings: The operation of gearbox gears will cause oil churning loss. When the gearbox is working for a long time, the internal temperature will rise sharply. The rise in temperature will lead to an increase in air pressure, causing lubricating oil to leak in the cover or other places. Important components such as bearings and oil seals will fail due to high temperature.
[0003] Because the location of the breather in the existing technology is unreasonable, the breather in the existing gearbox is generally placed on the tractor gearbox or the oil filler pipe. When working on a slope or plowing on the bank, the tractor tilts to one side, and there will always be oil on one side of the gearbox while the other side is short of oil for a long time. The gears on the side with oil will suffer from oil churning loss, while the gear bearings on the side with no oil will burn out. When running at high speed, the lubricating oil will be severely atomized, which will easily form an oil film at the gearbox breather, affecting the pressure relief and exhaust of the gearbox and causing the gearbox oil to overflow.
[0004] In existing technologies, the creeper gear is placed in the gearbox or shuttle gear housing, which results in a complex structure and an unreasonable distribution of working intensity among different gear positions. Summary of the Invention
[0005] This invention provides a multi-gear high-temperature resistant gearbox for medium and high horsepower tractors. Improvements in the position and structure of the breather inlet solve the problem of uneven oil storage on both sides of the gearbox when operating on slopes or plowing on the bank, and utilize the oil-blocking channel to complete the breathing function more smoothly.
[0006] To achieve the above objectives, the present invention provides a multi-speed high-temperature resistant gearbox for medium and high horsepower tractors, comprising a front box, a main gearbox, a secondary gearbox, a rear box, and a PTO box arranged sequentially from front to back. Power is transmitted sequentially from the front box, the main gearbox, the secondary gearbox, the rear box, and the PTO box, with the power output from the rear box to the rear wheel or the front wheel.
[0007] The rear storage compartment houses a creeper gear set, a front wheel output gear set, and a differential helical gear set. The creeper gear set and the front wheel output gear set are powered by the front end of the differential helical gear set. The front wheel output gear set outputs power to the front wheels to achieve four-wheel drive, while the two sides of the differential helical gear set output power to the rear wheels. The rear compartment is equipped with a vent, which is used for depressurizing and venting the transmission.
[0008] This invention features five housings: a front housing, a main gearbox, a secondary gearbox, a rear housing, and a PTO housing. The vent is positioned on the rear housing, in the middle of the tractor chassis. The distance from the vent to the high-temperature, high-pressure gas generated by the front and rear housings is approximately the same, ensuring the normal pressure relief and venting function of the entire gearbox. This effectively solves the problem of oil accumulation on one side of the gearbox and oil shortage on the other side during slope operation and plowing operations below the bank, ensuring the normal pressure relief and venting function of the entire gearbox and effectively preventing high-temperature oil leakage from the tractor gearbox.
[0009] This invention places the creep gear on the rear box, which reduces the speed of the creep gear pair by more than 9 times compared to the gearbox gear and the shuttle gear, and by more than 3 times compared to the large and small helical gears. This saves a pair of constantly meshing gears in the gearbox, and the number of gear pairs used in the main and auxiliary transmissions is the fewest among products of the same gear, resulting in lower costs and solving the problem of unreasonable distribution of working intensity of gears in different gear positions.
[0010] Preferably, the vent is positioned above the creeper gear set. Since the creeper gear is used infrequently in tractor operation, placing the vent above the creeper gear reduces the probability of lubricating oil splashing, minimizes direct splashing of lubricating oil at the vent, and significantly reduces oil loss due to gear churning, effectively preventing high-temperature oil leakage from the transmission.
[0011] Preferably, a partition is provided inside the rear housing, with the creeper gear set and the front wheel output gear set located in front of the partition, and the differential helical gear set located behind the partition. The partition design of the rear housing separates the creeper gear and the front output gear from the large and small helical gears and the PTO gear, thereby reducing the impact of gear oil churning on adjacent gears, reducing energy loss, and suppressing oil mist diffusion.
[0012] Preferably, the vent is located on the gearbox cover in the rear compartment, the gearbox cover is located at the top of the rear compartment, and an oil baffle is provided at the lower part of the gearbox cover. An oil baffle channel is provided through the oil baffle, and the oil baffle channel communicates with the vent. The oil baffle channel structure at the vent position of the gearbox cover of the present invention effectively prevents lubricating oil from splashing directly onto the vent.
[0013] Preferably, the vent and the oil baffle channel are perpendicular to each other, and the oil baffle channel is arranged horizontally in the longitudinal direction. The purpose of this design is to position the vent above the creep gear, with the oil baffle channel arranged horizontally in the longitudinal direction, that is, parallel to the shaft of each gear in the rear gearbox. When the gear at the vent rotates, the direction of lubricating oil splashing is perpendicular to the oil baffle channel of the vent, and the length of the oil baffle part can completely block the splashed oil, resulting in better performance.
[0014] Preferably, the oil-blocking channel is symmetrically arranged about the axis of the breather port, and the length of the oil-blocking channel is 3 to 4 times the diameter of the breather port. This dimensional parameter ensures, on the one hand, that the oil-blocking part can better cover the tooth width of the gear below, and that the length of the oil-blocking part is sufficient to prevent lubricating oil from splashing into the breather port. On the other hand, it also avoids the problem of air intake being obstructed because the oil-blocking channel is too long and its two ends are too close to the partition.
[0015] Preferably, the breather port is provided with a throttling orifice at the junction with the oil baffle channel. When the gearbox gears rotate at high speed, the lubricating oil will vaporize due to high temperature, producing oil vapor. The throttling orifice structure designed in the breather port can condense the oil vapor within a certain length of the breather port channel. The condensed oil falls back into the gearbox along the oil baffle channel under the action of gravity, thereby reducing oil leakage and seepage, and ensuring that the gas can more smoothly complete the breathing function using the oil baffle channel.
[0016] Preferably, the device further includes a groove at the bottom of the gearbox cover and reinforcing ribs at the edge of the groove. The grooves are symmetrically arranged in pairs on both sides of the oil baffle. The grooves and reinforcing ribs help to strengthen the gearbox cover. The bottom dimension of the groove is smaller than the opening dimension, that is, the groove is constructed with a downwardly widening structure, which facilitates the lubricating oil to flow down quickly after being splashed up.
[0017] Preferably, the present invention further includes an oil baffle plate disposed at the lower part of the rear housing, with the bottom of the large gear of the differential helical gear set located in the oil baffle plate. The oil baffle plate below the differential helical gear set prevents oil from splashing upwards from the bottom of the rear housing after being thrown by the large gear, thereby reducing oil churning losses and suppressing oil mist diffusion.
[0018] Compared with the prior art, the present invention has the following beneficial effects: In terms of cost: This invention arranges the crawler gear and the four-wheel drive gear separately on the rear box, saving a pair of constant mesh gears compared to tractor gearboxes of the same gear. The number of gear pairs used in the main and auxiliary transmissions is the smallest among products of the same gear; thus, the cost is lower.
[0019] In terms of functionality: The vent is positioned in the middle of the tractor chassis. The distance from the high-temperature and high-pressure gas generated by the front and rear gearboxes to the vent is basically the same, ensuring that the pressure relief and exhaust function of the entire gearbox is normal and effectively solving the problem of oil accumulation on one side of the gearbox and oil shortage on the other side when working on slopes or plowing on the bank.
[0020] An oil-blocking channel structure is set at the breather port, and when the gear at the breather port rotates, the direction of lubricating oil splashing is perpendicular to the oil-blocking channel at the breather port, effectively preventing lubricating oil from splashing directly onto the breather port.
[0021] When the gearbox gears rotate at high speed, the lubricating oil will vaporize due to high temperature and produce oil gas. The throttle orifice structure designed in the breather can condense the oil gas in the breather channel of a certain length. The condensed oil falls back into the gearbox along the oil baffle channel under the action of gravity, thereby reducing the occurrence of oil leakage and seepage, and also ensuring that the gas can complete the breathing function more smoothly by utilizing the oil baffle channel.
[0022] By placing the crawler gear on the rear box, the speed of the crawler gear pair is reduced by more than 9 times compared to the transmission gear and shuttle gear, and by more than 3 times compared to the large and small helical gears. Moreover, the crawler gear is used infrequently in tractor operation. Therefore, the transmission vent is placed above the crawler gear, which reduces the direct splashing of lubricating oil at the transmission vent and greatly reduces the loss of oil churning in the gears, effectively preventing transmission oil leakage due to high temperature.
[0023] The rear housing is designed with a partition to separate the creep gear set, the front wheel output gear set, the differential helical gear set, and the gears of the PTO gearbox. The helical gear is also designed with an oil baffle, which reduces gear oil churning loss and suppresses oil mist diffusion. The transmission has good cooling and heat dissipation performance and good high temperature resistance.
[0024] Traditional tractor gearbox transmission structures typically place the crawler gear in the front box or gearbox and the crawler gear on the rear box. This saves a pair of constantly meshing gears in the gearbox and solves the problem of unreasonable distribution of working intensity among different gears.
[0025] In terms of performance: It solves the problem of oil accumulation on one side of the gearbox and oil shortage on the other side when operating on slopes and plowing on the bank, effectively ensuring the normal pressure relief and venting function of the entire gearbox, and effectively avoiding high temperature oil leakage in tractor gearboxes. Attached Figure Description
[0026] Figure 1 This is a simplified structural diagram of a multi-gear high-temperature resistant gearbox for medium and high horsepower tractors, as described in this invention.
[0027] Figure 2 This is a cross-sectional view of the rear box described in this invention.
[0028] Figure 3 This is a schematic diagram illustrating the working principle of the oil baffle described in this invention.
[0029] Figure 4 This is a bottom view of the gearbox cover described in this invention.
[0030] Figure 5 This is a cross-sectional view of the gearbox cover described in this invention.
[0031] In the diagram: 1-Front gearbox, 2-Main gearbox, 3-Auxiliary gearbox, 4-Rear gearbox, 5-PTO gearbox, 6-Crawler gear set, 7-Front wheel output gear set, 8-Differential helical gear set, 9-Breaker, 10-Block plate, 11-Gearbox cover, 1101-Oil baffle, 1102-Oil baffle passage, 1103-Throttle port, 1104-Groove, 1105-Reinforcing rib, 12-Oil baffle plate. Detailed Implementation
[0032] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention.
[0033] In the description of this invention, it should be understood that the terms "left", "right", "up", "down", "front", "back", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or structure referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention. Example
[0034] like Figure 1 and Figure 2 As shown, a multi-gear high-temperature resistant gearbox for medium and high horsepower tractors is characterized by comprising a front housing 1, a main gearbox 2, a secondary gearbox 3, a rear housing 4, and a PTO housing 5 arranged sequentially from front to back. The rear housing 4 is equipped with a creeper gear set 6, a front wheel output gear set 7, and a differential helical gear set 8. The creeper gear set 6 and the front wheel output gear set 7 are poweredly connected to the front end of the differential helical gear set 8. The front wheel output gear set 7 outputs power to the front wheel, and the two sides of the differential helical gear set 8 output power to the rear wheel. A vent 9 is provided on the rear housing 4.
[0035] like Figure 1As shown, this embodiment has five housings: front housing 1, main gearbox 2, auxiliary gearbox 3, rear housing 4, and PTO housing 5. The vent 9 is positioned on the shell of the rear housing 4, which is in the middle of the entire tractor chassis. The distance from the high-temperature and high-pressure gas generated by the front housing 1 and the rear housing 4 to the vent 9 is basically the same, ensuring that the pressure relief and exhaust function of the entire gearbox is normal and effectively solving the problem of oil accumulation on one side of the gearbox and oil shortage on the other side when working on slopes or plowing on the bank. This effectively ensures the normal pressure relief and exhaust function of the entire gearbox and effectively avoids high-temperature oil leakage from the tractor gearbox.
[0036] Example 2: A high-temperature resistant multi-gear transmission for medium and high horsepower tractors.
[0037] like Figure 1 As shown, in this embodiment, the front-to-back direction is defined as the power transmission flow direction, that is, the front box 1 is in front and the PTO box 5 is in the back.
[0038] like Figure 1 and Figure 2 As shown, a multi-speed high-temperature resistant gearbox for medium and high horsepower tractors includes a front box 1, a main gearbox 2, a secondary gearbox 3, a rear box 4, and a PTO box 5 arranged sequentially from front to back. Power is transmitted sequentially from the front box 1, the main gearbox 2, the secondary gearbox 3, the rear box 4, and the PTO box 5, and the power output from the rear box 4 is sent to the rear wheel or the front wheel.
[0039] The rear box 4 is equipped with a creeper gear set 6, a front wheel output gear set 7, and a differential helical gear set 8. The creeper gear set 6 and the front wheel output gear set 7 are powered by the front end of the differential helical gear set 8. The front wheel output gear set 7 outputs power to the front wheels to achieve four-wheel drive, and the two sides of the differential helical gear set 8 output power to the rear wheels. The rear box 4 is provided with a vent 9, which is used for depressurization and exhaust of the gearbox.
[0040] like Figure 3 As shown, in this embodiment, the breather 9 is positioned above the creeper gear set 6. Since the creeper gear is used infrequently in tractor operation, placing the breather 9 of the gearbox above the creeper gear set reduces the probability of lubricating oil splashing, minimizes direct splashing of lubricating oil onto the breather 9, and significantly reduces oil loss from gear churning, effectively preventing high-temperature oil leakage from the gearbox.
[0041] like Figure 2 As shown, in this embodiment, a partition 10 is provided inside the housing of the rear box 4, the creep gear set 6 and the front wheel output gear set 7 are located in front of the partition 10, and the differential helical gear set 8 is located behind the partition 10.
[0042] like Figure 1 and Figure 2 As shown, the rear housing 4 is designed with a partition 10 to separate the crawling gear, the front output gear, the large and small helical gears, and the PTO gear, thereby reducing the impact of gear oil churning on adjacent gears, reducing energy loss, and suppressing oil mist diffusion.
[0043] like Figure 2 As shown, in this embodiment, the breathing port 9 is disposed on the gearbox cover 11 of the rear box 4, and the gearbox cover 11 is disposed on the top of the rear box 4. like Figures 3-5 As shown, an oil baffle 1101 is provided at the lower part of the gearbox cover 11, and an oil baffle channel 1102 is provided through the oil baffle 1101. The oil baffle channel 1102 is connected to the vent 9.
[0044] like Figure 3 As shown, the transmission cover 11 of the present invention has an oil blocking channel 1102 structure at the vent 9 position. When the gear of the creep gear set 6 rotates counterclockwise, it drives the lubricating oil to splash upwards. The lubricating oil is blocked by the oil blocking part 1101, which effectively prevents the lubricating oil from splashing directly to the vent 9.
[0045] like Figure 5 As shown, in this embodiment, the vent 9 and the oil baffle channel 1102 are perpendicular to each other, and the oil baffle channel 1102 is arranged horizontally in the longitudinal direction. The purpose of this design is to arrange the vent 9 above the creep gear, and the oil baffle channel 1102 is arranged horizontally in the longitudinal direction, that is, parallel to the shaft of each gear in the rear housing 4. When the gear at the vent 9 rotates, the direction of lubricating oil splashing is perpendicular to the oil baffle channel 1102 of the vent 9. The length of the oil baffle 1101 can completely block the splashed oil, resulting in better performance.
[0046] like Figure 5 As shown, in this embodiment, the oil-blocking channel 1102 is symmetrically arranged about the axis of the breather 9, and the length L of the oil-blocking channel 1102 is 3 to 4 times the diameter D of the breather 9. This dimensional parameter ensures, on the one hand, that the oil-blocking part 1101 can better cover the tooth width of the gear below, and that the length of the oil-blocking part 1101 is sufficient to prevent lubricating oil from splashing into the breather 9. On the other hand, it also avoids the problem that if the oil-blocking channel 1102 is too long, the two ends of the oil-blocking channel 1102 will be too close to the partition 10, thus obstructing air intake.
[0047] In this embodiment, the breather 9 is provided with a throttling orifice 1103 at the junction with the oil-blocking channel 1102. When the gearbox gears are running at high speed, the lubricating oil will vaporize due to high temperature to produce oil vapor. The throttling orifice structure designed in the breather 9 can condense the oil vapor within a certain length of the breather 9 channel. The condensed oil falls back into the gearbox along the oil-blocking channel 1102 under the action of gravity, thereby reducing the occurrence of oil leakage and seepage, and also ensuring that the gas can more smoothly complete the breathing function using the oil-blocking channel 1102.
[0048] This embodiment also includes a groove 1104 disposed at the bottom of the gearbox cover 11 and reinforcing ribs 1105 disposed at the edge of the groove 1104. The grooves 1104 are symmetrically arranged in pairs on both sides of the oil baffle 1101. The grooves 1104 and reinforcing ribs 1105 help to strengthen the gearbox cover 11. The bottom dimension of the groove 1104 is smaller than the opening dimension, that is, the groove 1104 is constructed with a downwardly widening structure, which facilitates the lubricating oil to flow down quickly after being splashed up.
[0049] This embodiment also includes an oil baffle 12 disposed at the lower part of the rear housing 4, with the bottom of the large gear of the differential helical gear set 8 located in the oil baffle 12. The oil baffle 12 is designed below the differential helical gear set 8 to prevent oil from splashing from the bottom of the rear housing 4 onto the top after being thrown by the large gear of the differential helical gear set 8, thereby reducing oil churning loss and suppressing oil mist diffusion.
Claims
1. A multi-speed, high-temperature resistant gearbox for medium and high horsepower tractors, characterized in that... The gearbox includes a front box (1), a main gearbox (2), a secondary gearbox (3), a rear box (4), and a PTO box (5) arranged sequentially from front to back. The rear box (4) is equipped with a creeper gear set (6), a front wheel output gear set (7), and a differential helical gear set (8). The creeper gear set (6) and the front wheel output gear set (7) are powered to the front end of the differential helical gear set (8). The front wheel output gear set (7) outputs power to the front wheel, and the two sides of the differential helical gear set (8) output power to the rear wheel. The rear box (4) is equipped with a vent (9).
2. The high-temperature resistant multi-gear transmission for medium and high horsepower tractors according to claim 1, characterized in that: The breathing port (9) is located above the crawling gear set (6).
3. The high-temperature resistant multi-gear transmission for medium and high horsepower tractors according to claim 1, characterized in that: The rear box (4) has a partition (10) inside its housing. The creep gear set (6) and the front wheel output gear set (7) are located in front of the partition (10), and the differential helical gear set (8) is located behind the partition (10).
4. The high-temperature resistant multi-gear transmission for medium and high horsepower tractors according to claim 1, characterized in that: The breathing port (9) is located on the gearbox cover (11) of the rear box (4). The gearbox cover (11) is located on the top of the rear box (4). The gearbox cover (11) has an oil baffle (1101) at the bottom. The oil baffle (1101) has an oil baffle channel (1102) through it. The oil baffle channel (1102) is connected to the breathing port (9).
5. The high-temperature resistant multi-gear transmission for medium and high horsepower tractors according to claim 4, characterized in that: The breathing port (9) and the oil-blocking channel (1102) are perpendicular to each other, and the oil-blocking channel (1102) is set horizontally in the longitudinal direction.
6. The high-temperature resistant multi-gear transmission for medium and high horsepower tractors according to claim 4, characterized in that: The oil-blocking channel (1102) is symmetrically arranged about the axis of the breathing port (9), and the length of the oil-blocking channel (1102) is 3 to 4 times the diameter of the breathing port (9).
7. The high-temperature resistant multi-gear transmission for medium and high horsepower tractors according to claim 4, characterized in that: The breathing port (9) is provided with a throttle port (1103) at the junction with the oil blocking channel (1102).
8. A multi-speed high-temperature resistant gearbox for medium and high horsepower tractors according to claim 4, characterized in that: It also includes a groove (1104) provided at the bottom of the gearbox cover (11), the bottom size of the groove (1104) being smaller than the opening size, and reinforcing ribs (1105) provided at the edge of the groove (1104). The grooves (1104) are symmetrically arranged in pairs on both sides of the oil baffle (1101).
9. A multi-gear high-temperature resistant gearbox for medium and high horsepower tractors according to claim 1, characterized in that: It also includes an oil baffle (12) provided at the lower part of the rear box (4), and the bottom of the large gear of the differential helical gear set (8) is located in the oil baffle (12).