Hydrostatic transmission gearbox for engineering machinery and engineering machinery

Abstract

The utility model relates to a hydrostatic transmission gearbox for engineering machinery, which comprises a gearbox body, the gearbox body comprises a first shell and a second shell which are fixedly connected with each other and a box body cavity defined by the first shell and the second shell, and the first shell is provided with a lubricating oil inlet; the speed change valve is provided with a lubricating oil outlet and fixedly mounted to the first shell, and the lubricating oil outlet is configured to be aligned with the lubricating oil inlet; a first input shaft supported in an upper region of the housing chamber through a first bearing provided at the first housing and a second bearing provided at the second housing, the first input shaft being coupled with the first motor via a first flange adjacent to the second bearing; the first main lubricating oil flow channel is arranged in the first shell and is in fluid communication with the lubricating oil inlet; the second main lubricating oil flow channel extends out of the first main lubricating oil flow channel; and a first lubricating oil flow passage for the first bearing and a second lubricating oil flow passage for the second bearing in fluid communication with the second main lubricating oil flow passage. The utility model further provides engineering machinery.

Description

Technical Field

[0001] The utility model relates to the technical field of gearboxes for engineering machinery / operating machinery, in particular to a hydrostatic transmission gearbox with an improved bearing lubrication flow channel. Background Art

[0002] Hydrostatic transmission, which is a combination of engine, pump, motor and gearbox, can reduce fuel consumption by about 20% compared with the traditional transmission route, which is a combination of engine, torque converter and gearbox. In recent years, it has been widely used in the field of construction machinery, especially loaders.

[0003] For bearings, adequate lubrication is necessary, which can form a lubricating oil film on the rolling elements, remove pollutants and heat in time, and reduce power loss. In the common hydrostatic transmission in the industry, the lubrication of the clutch shaft end bearing is mostly forced lubrication, but for shafts without clutches, the lubrication of the shaft end bearing is mostly splashed by the oil thrown up by the gear shafts. Splash lubrication has high requirements on the structure. In places where splashing is difficult, especially in large-tonnage loaders, the lubrication effect is far inferior to forced lubrication. Utility Model Content

[0004] In order to overcome at least one aspect of the above problems, it is necessary to provide a hydrostatic transmission gearbox for engineering machinery, which has an improved bearing lubrication flow channel, is suitable for forced lubrication of bearings at a higher position in the case chamber, and does not require a lubricating oil pipeline to be set outside the gearbox.

[0005] The utility model provides a hydrostatic transmission gearbox for engineering machinery, which comprises: a gearbox case, the gearbox case comprising a first shell and a second shell fixedly connected to each other and a case chamber defined by the first shell and the second shell, wherein the first shell is provided with a lubricating oil inlet; a speed change valve, the speed change valve having a lubricating oil outlet and fixedly mounted to the first shell, wherein the lubricating oil outlet is configured to be aligned with the lubricating oil inlet; a first input shaft, the first input shaft being supported in an upper region of the case chamber by a first bearing arranged at the first shell and a second bearing arranged at the second shell, wherein the first input shaft is connected to the first motor via a first flange adjacent to the second bearing; a first main lubricating oil flow channel arranged in the first shell and in fluid communication with the lubricating oil inlet and a second main lubricating oil flow channel extending from the first main lubricating oil flow channel; and a first lubricating oil flow channel for the first bearing and a second lubricating oil flow channel for the second bearing in fluid communication with the second main lubricating oil flow channel. In this article, the first shell may also be referred to as a "case cover", and the second shell may also be referred to as a "case", or vice versa.

[0006] According to a preferred embodiment of the present invention, a first main lubricating oil flow channel extends along the axial direction of the first input shaft, and a second main lubricating oil flow channel extends vertically upward perpendicular to the first main lubricating oil flow channel, wherein the first lubricating oil flow channel extends in the first housing perpendicular to the second main lubricating oil flow channel toward the first bearing, wherein the first lubricating oil flow channel has a first port leading to the first bearing; and the second lubricating oil flow channel includes a first flow channel section extending in the first housing perpendicular to the second main lubricating oil flow channel toward the second housing, a second flow channel section extending in the second housing, and a third flow channel section extending perpendicular to the second flow channel section toward the second bearing, wherein the third flow channel section has a second port leading to the second bearing.

[0007] In a preferred embodiment of the present invention, a first throttling screw is provided in the first lubricating oil flow channel; and a first through hole is provided at one end of the first flange close to the second bearing, the first through hole is configured to be aligned with the second port and its size is smaller than the size of the second port. It should be understood that the "size" here may refer to the cross-sectional area of ​​the first through hole and the second port, or the diameter of the through hole or the port.

[0008] In one embodiment of the present invention, the hydrostatic transmission gearbox also includes: a second input shaft, which is supported in the upper area of ​​the housing chamber by a third bearing arranged at the first housing and a fourth bearing arranged at the second housing, wherein the second input shaft is connected to the second motor via a second flange adjacent to the fourth bearing; and a third main lubricating oil flow channel extending from the second main lubricating oil flow channel, a third lubricating oil flow channel for the third bearing and a fourth lubricating oil flow channel for the fourth bearing which are fluidically connected to the third main lubricating oil flow channel.

[0009] According to a preferred embodiment of the utility model, the third main lubricating oil flow channel extends horizontally toward the third bearing in the first housing perpendicular to the second main lubricating oil flow channel, wherein the third lubricating oil flow channel extends perpendicular to the third main lubricating oil flow channel toward the third bearing, wherein the third lubricating oil flow channel has a third port leading to the third bearing; and the fourth lubricating oil flow channel includes a fourth flow channel section extending perpendicularly to the third main lubricating oil flow channel toward the second housing, a fifth flow channel section extending in the second housing and a sixth flow channel section extending perpendicularly to the fifth flow channel section toward the fourth bearing, wherein the sixth flow channel section has a fourth port leading to the fourth bearing.

[0010] In a preferred embodiment of the present invention, a second throttling screw is provided in the third lubricating oil flow channel; and a second through hole is provided at one end of the second flange close to the fourth bearing, the second through hole is configured to be aligned with the fourth port and its size is smaller than the size of the fourth port. Similarly, the "size" here can be understood as the cross-sectional area of ​​the first through hole and the second port, or the diameter of the through hole or the port.

[0011] According to one scheme of the utility model, the hydrostatic transmission gearbox also includes an output shaft having an output gear, which is supported in the lower area of ​​the housing chamber by a fifth bearing away from the output gear and a sixth bearing close to the output gear, wherein the fifth bearing is arranged in a bearing chamber defined by a bearing seat housing; wherein an oil inlet hole is provided on the upper side of the bearing seat housing and an oil drain hole is provided on the lower side of the bearing seat housing, and both the oil inlet hole and the oil drain hole are connected to the fluid in the bearing chamber.

[0012] According to a preferred solution of the utility model, a first sealing ring is provided at the joint of the first flange and the second shell; a second sealing ring is provided at the joint of the first flow channel section and the second flow channel section. A third sealing ring is provided at the joint of the second flange and the second shell; a fourth sealing ring is provided at the joint of the fourth flow channel section and the fifth flow channel section.

[0013] The utility model also provides an engineering machine, which comprises the above-mentioned hydrostatic transmission gearbox.

[0014] The beneficial effects of the gearbox according to the utility model are at least as follows: lubricating oil flow channels are arranged in the case body and case cover of the gearbox, so that bearings at higher positions, such as bearings for input shafts, are forced to be lubricated; the pressure and flow of the lubricating oil are adjusted by adjusting the size of the lubricating oil port, such as adding a throttling screw in the lubricating oil channel, or changing the orifice size; by directly fluidically connecting the main lubricating oil flow channel with the lubricating oil outlet in the shift valve, there is no need to arrange additional oil pipes and external flow channels, thereby reducing costs and oil leakage risks; an oil inlet hole and an oil outlet hole are arranged in the bearing seat housing of the output shaft located in the lower area of ​​the case chamber, such as the bearing away from the output gear, thereby improving the lubrication condition of the shaft end bearing of the output shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The features and advantages of the present invention will be clearly understood through the detailed description provided below with reference to the accompanying drawings. It should be understood that the following drawings are merely schematic and not necessarily drawn to scale, and thus cannot be regarded as limiting the present invention, wherein:

[0016] Figure 1A perspective view of an embodiment of a hydrostatic transmission gearbox for engineering machinery according to the utility model is shown, wherein the hydrostatic transmission gearbox is connected to a first motor and a second motor;

[0017] Figure 2 for Figure 1 A side view of a hydrostatic transmission gearbox is shown;

[0018] Figure 3 for Figure 2 A partial sectional view AA of the hydrostatic transmission gearbox shown;

[0019] Figure 3A for Figure 3 A partial enlarged view of the layout of the lubricating oil flow channel for the bearing shown in FIG.

[0020] Figure 4 for Figure 2 A partial cross-sectional view of the CC of the hydrostatic transmission gearbox shown;

[0021] Figure 4A for Figure 4 A partial enlarged view of the layout of the lubricating oil flow channel for the bearing shown in FIG.

[0022] Figure 5 for Figure 1 A front view of a hydrostatic transmission gearbox is shown;

[0023] Figure 6 for Figure 5 A partial cross-sectional view BB of the hydrostatic transmission gearbox shown;

[0024] Fig. 6A for Figure 6 A partial enlarged view of the layout of the lubricating oil flow channel for the bearing shown in FIG.

[0025] Figure 7 for Figure 1 A side view of a hydrostatic transmission transmission is shown;

[0026] Figure 8 for Figure 7 DD partial section view of the hydrostatic transmission gearbox shown; and

[0027] Fig. 8A for Figure 8 A partial enlarged view of the layout of the lubricating oil flow channel for the bearing shown in FIG. DETAILED DESCRIPTION

[0028] Embodiments of the present invention are described below with reference to the accompanying drawings. In the following description, many specific details are set forth so that those skilled in the art can more fully understand and implement the present invention. In addition, it should be understood that the present invention is not limited to the specific embodiments described. On the contrary, any combination of the features and elements described below can be considered to implement the present invention, regardless of whether they involve different embodiments. Therefore, the following aspects, features, embodiments and advantages are for illustrative purposes only and should not be regarded as elements or limitations of the claims unless explicitly stated in the claims.

[0029] In the following, terms such as "first", "second", etc. are used to describe the elements of the present application. These terms are only used to distinguish the various elements, and are not used to limit the nature, order or number of these elements. The terms "including" and "having" are used to express an open-ended inclusive meaning, and mean that there may be additional elements / components in addition to the listed elements / components.

[0030] Figure 1 An embodiment of a hydrostatic transmission gearbox / transmission 100 for engineering machinery according to the present invention is shown. Figure 2 for Figure 1 The illustrated diagram is a side view of a side of the hydrostatic transmission gearbox 100 on which the shift valve 2 is mounted. Figure 3 for Figure 2 AA partial section view of the hydrostatic transmission gearbox in.

[0031] As can be seen from the figure, in this embodiment, the hydrostatic transmission gearbox 100 may include a gearbox housing 1, a speed change valve 2 and a first input shaft 3, wherein the gearbox housing 1 includes a first housing 11 (also referred to as a housing cover) and a second housing 12 (also referred to as a housing) fixedly connected to each other, and the first housing and the second housing define a housing chamber suitable for accommodating the first input shaft 3, and the first input shaft 3 is supported in the upper region of the housing chamber by a first bearing 31 provided at the first housing 11 and a second bearing 32 provided at the second housing 12. The speed change valve 2 is fixedly mounted to the first housing 11 at one side of the gearbox housing 1, and the first input shaft 3 is connected to the first motor 21 via a first flange 211 adjacent to the second bearing 32. Advantageously, the first housing 11 is provided with a lubricating oil inlet 10, and the speed change valve 2, especially the speed change valve housing, is provided with a lubricating oil outlet 20, and in the installed state of the speed change valve, the lubricating oil inlet 10 and the lubricating oil outlet 20 are aligned and fluidly connected. Advantageously, a sealing ring is provided between the lubricating oil inlet and the lubricating oil outlet.

[0032] See especially Figure 3AIn this embodiment, in order to force lubricate the first bearing 31 and the second bearing 32 located in the upper area of ​​the housing chamber to improve the lubrication effect on the bearings, a first main lubricating oil flow channel P1 extending from the lubricating oil inlet 10, for example, along the axial direction of the first input shaft 3 (i.e., fluidly connected thereto), and a second main lubricating oil flow channel P2 extending vertically upward, for example, perpendicular to the first main lubricating oil flow channel P1 are provided in the first housing 11. In one example, the first lubricating oil flow channel L1 for supplying lubricating oil to the first bearing 31 located on the side of the first housing 11 extends perpendicularly to the second main lubricating oil flow channel P2 toward the first bearing 31 in the first housing 11, and the first lubricating oil flow channel has a first port 13 leading to the first bearing, so that the lubricating oil from the first lubricating oil flow channel L1 can force lubricate the first bearing 31. Preferably, a first throttle screw 13a can also be provided in the first lubricating oil flow channel L1, for example, it can be arranged close to the first port to adjust the fluid pressure and oil outlet state of the first port to ensure that the lubricating oil flowing out of the first port 13 meets the pressure and flow requirements.

[0033] In the above example, the second lubricating oil flow channel L2 for supplying lubricating oil to the second bearing 32 located on the second housing 12 side includes three sections, namely, a first flow channel section L21 extending toward the second housing 12 perpendicularly to the second main lubricating oil flow channel P2 in the first housing 11 and, for example, parallel to the axial direction of the first input shaft 3, a second flow channel section L22 aligned with the first flow channel section L21 and extending in the second housing 12, and a third flow channel section L23 extending toward the second bearing 32 perpendicularly to the second flow channel section, and the third flow channel section has a second port 23 leading to the second bearing 32, so that the lubricating oil from the second lubricating oil flow channel L2 can force lubricate the second bearing 22. Advantageously, in order to control the fluid pressure and oil discharge state from the second port 23 to the second bearing 23, a first through hole 2110 may be provided at one end of the first flange 211 close to the second bearing 32. The first through hole is configured to align with the second port 23 and its size is smaller than the size of the second port. The small-sized first through hole plays the same role as the throttle screw, and can ensure that the lubricating oil flowing out of the first through hole meets the pressure and flow requirements. In a preferred embodiment, the cross-sections of the first through hole and the second port may both be circular, that is, the diameter of the second port is significantly larger than the diameter of the first through hole. Preferably, a first sealing ring 121 may also be provided at the joint between the first flange 211 and the second housing 12, and a second sealing ring 122 may be provided at the joint between the first flow channel section L21 and the second flow channel section L22. In addition, sealing gaskets are also provided between the first flange 211 and the first motor 21, and between the second flange 221 and the second motor 22.

[0034] According to a preferred embodiment of the present invention, see Figure 4 , Figure 4A , Figure 5 and Figure 6 The hydrostatic transmission gearbox 100 also includes a second input shaft 4, which is supported in the upper area of ​​the housing chamber by a third bearing 41 arranged at the first housing 11 and a fourth bearing 42 arranged at the second housing 12, wherein the second input shaft 4 is connected to the second motor 22 via a second flange 221 adjacent to the fourth bearing.

[0035] See especially Figure 4A and Fig. 6A Advantageously, the lubricating oil passages for forced lubrication of the third bearing 41 and the fourth bearing 42 further include a third main lubricating oil passage P3 extending horizontally in the first housing 11, for example, perpendicular to the second main lubricating oil passage P1, a third lubricating oil passage L3 for the third bearing 41 in fluid communication with the third main lubricating oil passage P3, and a fourth lubricating oil passage L4 for the fourth bearing 42. Fig. 6A It can be seen that the third lubricating oil flow channel L3 extends perpendicularly to the third main lubricating oil flow channel P3 toward the third bearing 41, and the third lubricating oil flow channel has a third port 33 leading to the third bearing, so that the lubricating oil from the third lubricating oil flow channel L3 can force lubricate the third bearing 41. Preferably, a second throttle screw 33a can be provided in the third lubricating oil flow channel L3, for example, near the third port 33, to adjust the fluid pressure and oil outlet state at the third port, and ensure that the lubricating oil flowing out of the third port 33 meets the pressure and flow requirements. See in particular Figure 4AThe fourth lubricating oil flow channel L4 includes three sections, namely, a fourth flow channel section L41 extending from the third main lubricating oil flow channel P3 toward the second housing 12 in the first housing 11, a fifth flow channel section L42 extending aligned with the third flow channel section in the second housing, and a sixth flow channel section L43 extending perpendicular to the fifth flow channel section toward the fourth bearing 42, wherein the sixth flow channel section has a fourth port 43 leading to the fourth bearing, so that the lubricating oil from the fourth lubricating oil flow channel L4 can force lubricate the fourth bearing 42. Advantageously, in order to control the fluid pressure and flow from the fourth port 43 to the fourth bearing 42, a second through hole 2210 can be provided at one end of the second flange 221 close to the fourth bearing 42, the second through hole is configured to align with the fourth port 43 and its size is smaller than the size of the fourth port, and the small-sized second through hole is provided to play the same role as the throttling screw, which can ensure that the lubricating oil flowing out of the second through hole meets the pressure and flow requirements. In a preferred embodiment, the cross-sections of the second through hole and the fourth port can both be circular, that is, the diameter of the fourth port is significantly larger than the diameter of the second through hole. Preferably, a third sealing ring 123 can also be provided at the joint between the second flange 221 and the second housing 12, and a second sealing ring 124 can be provided at the joint between the fourth flow channel section L41 and the fifth flow channel section L42.

[0036] According to one embodiment of the present invention, see Figure 7 , Figure 8 and Fig. 8A The hydrostatic transmission gearbox 100 further includes an output shaft 5 having an output gear Z, which is supported in the lower region of the housing chamber by a fifth bearing 51 away from the output gear and a sixth bearing (not shown) close to the output gear, wherein the fifth bearing 51 is arranged in a bearing chamber 52 defined by a bearing seat housing 50. Since the output shaft 5 is located in the lower region of the housing chamber, a large amount of lubricating oil can splash down from the output shaft 5 to lubricate the fifth bearing and the sixth bearing; however, since the bearings are assembled in the bearing seat housing, the housing blocks the lubricating oil. In addition, the output gear Z will also stir up the lubricating oil in the oil pan to lubricate the sixth bearing close to the output gear, but the fifth bearing 51 far from the output gear is still difficult to be lubricated. In order to solve this problem, in this embodiment, an oil inlet hole 501 is provided on the upper side of the bearing seat housing 50, and an oil drain hole 502 is provided on the lower side of the bearing seat housing 50, and the oil inlet hole and the oil drain hole are both in fluid communication with the bearing chamber 51, so that splashed lubricating oil can flow into the bearing chamber from the upper oil inlet hole 501 and flow out of the bearing chamber from the lower oil drain hole 502, thereby obtaining more lubricating oil and forming a flow cycle to take away heat. In this embodiment, the bearing seat housing 50 is a part of the second housing and is made integrally therewith.

[0037] In the present invention, there is also provided an engineering machine, which comprises the above-mentioned hydrostatic transmission gearbox with improved bearing lubrication. The engineering machine may be a grader, a bulldozer or a roller, in particular, a variety of engineering machines with a hydrostatic transmission gearbox.

[0038] Industrial Applicability

[0039] The gearbox according to the utility model can be applied to various engineering machines, such as graders, loaders, bulldozers or road rollers.

[0040] Combine the following Figure 3A , Figure 4A and Fig. 6A and Fig. 8A Briefly introduce the gearbox 100 for engineering machinery according to the utility model, especially the bearing lubrication of the dual-input two-speed hydrostatic transmission gearbox:

[0041] During normal operation, the first bearing 31 and the second bearing 32 of the first input shaft 3 and the third bearing 41 and the fourth bearing 42 of the second input shaft 4 located in the upper area of ​​the housing chamber of the gearbox housing 1 need to be lubricated.

[0042] See Figure 3A Through the lubricating oil passages for bearings provided in the first housing and the second housing, the lubricating oil from the lubricating oil outlet 20 of the speed change valve 2 flows from the lubricating oil inlet 10 through the first main lubricating oil flow passage P1 and the second main lubricating oil flow passage P2 in sequence, and then enters the first lubricating oil flow passage L1 and the second lubricating oil flow passage L2 respectively from the second main lubricating oil flow passage, flows from the first port 13 to the first bearing 31 for forced lubrication thereof, and flows from the second port 23 through the first through hole 2110 to the second bearing 32 for forced lubrication thereof.

[0043] See also Figure 4A and Fig. 6A The lubricating oil from the lubricating oil outlet 20 of the speed change valve 2 flows from the lubricating oil inlet 10 through the first main lubricating oil flow channel P1, the second main lubricating oil flow channel P2 and the third main lubricating oil channel P3 in sequence, and then enters the third lubricating oil flow channel L3 and the fourth lubricating oil flow channel L4 from the third main lubricating oil flow channel respectively, flows from the third port 33 to the third bearing 41 for forced lubrication, and flows from the fourth port 34 and through the second through hole 2210 to the fourth bearing 42 for forced lubrication.

[0044] See also Fig. 8A During the operation of the hydrostatic transmission gearbox, splashed lubricating oil flows into the bearing chamber 51 from the upper oil inlet hole 501, and then flows out of the bearing chamber 52 from the lower oil discharge hole 502, thereby obtaining more lubricating oil and forming a flow cycle to take away heat, thereby improving the lubrication condition of the shaft end bearing of the output shaft.

[0045] For those skilled in the art, various modifications and variations may be made to the embodiments disclosed above without departing from the scope or spirit of the utility model. Other embodiments of the utility model will be apparent to those skilled in the art from the practice of the utility model disclosed in this specification. This specification and the examples disclosed therein should be considered to be illustrative only, and the true scope of the utility model is specified by the appended claims and their equivalents.

Claims

1. A hydrostatic transmission gearbox for engineering machinery, characterized in that: The hydrostatic transmission gearbox (100) comprises: A gearbox case (1), comprising a first shell (11) and a second shell (12) fixedly connected to each other, and a case chamber defined by the first shell and the second shell, wherein the first shell (11) is provided with a lubricating oil inlet (10); a speed change valve (2) having a lubricating oil outlet (20) and fixedly mounted to the first housing, wherein the lubricating oil outlet (20) is configured to align with the lubricating oil inlet (10); a first input shaft (3), the first input shaft being supported in an upper region of the housing chamber via a first bearing (31) disposed at the first housing (11) and a second bearing (32) disposed at the second housing (12), wherein the first input shaft (3) is coupled to the first motor (21) via a first flange (211) adjacent to the second bearing (32); A first main lubricating oil flow passage (P1) disposed in the first housing and in fluid communication with the lubricating oil inlet (10) and a second main lubricating oil flow passage (P2) extending from the first main lubricating oil flow passage; and A first lubricating oil flow passage (L1) for the first bearing (31) and a second lubricating oil flow passage (L2) for the second bearing (32) are fluidically connected to the second main lubricating oil flow passage (P2).

2. The hydrostatic transmission gearbox according to claim 1, characterized in that: The first main lubricating oil flow channel (P1) extends in the axial direction of the first input shaft (3), and the second main lubricating oil flow channel (P2) extends vertically upward perpendicularly to the first main lubricating oil flow channel (P1), wherein the first lubricating oil flow channel (L1) extends in the first housing perpendicularly to the second main lubricating oil flow channel (P2) toward the first bearing, wherein the first lubricating oil flow channel has a first port (13) leading to the first bearing; and The second lubricating oil flow channel (L2) includes a first flow channel section (L21) extending in the first housing perpendicularly to the second main lubricating oil flow channel (P2) toward the second housing, a second flow channel section (L22) extending in the second housing, and a third flow channel section (L23) extending perpendicularly to the second flow channel section toward the second bearing (32), wherein the third flow channel section has a second port (23) leading to the second bearing.

3. The hydrostatic transmission gearbox according to claim 2, characterized in that: A first throttle screw (13a) is provided in the first lubricating oil flow passage (L1); and A first through hole (2110) is provided at one end of the first flange (211) close to the second bearing (32). The first through hole is configured to be aligned with the second port (23) and has a size smaller than that of the second port.

4. The hydrostatic transmission gearbox according to claim 2 or 3, characterized in that: The hydrostatic transmission gearbox (100) further comprises: a second input shaft (4), the second input shaft being supported at an upper region within the housing chamber by a third bearing (41) disposed at the first housing (11) and a fourth bearing (42) disposed at the second housing (12), wherein the second input shaft (4) is coupled to the second motor (22) via a second flange (221) adjacent to the fourth bearing; and A third main lubricating oil flow channel (P3) extending from the second main lubricating oil flow channel (P2), a third lubricating oil flow channel (L3) for the third bearing (41) and a fourth lubricating oil flow channel (L4) for the fourth bearing (42) fluidly connected to the third main lubricating oil flow channel (P3).

5. The hydrostatic transmission gearbox according to claim 4, characterized in that: The third main lubricating oil flow channel (P3) extends horizontally in the first housing perpendicularly to the second main lubricating oil flow channel (P2) toward the third bearing (41), wherein the third lubricating oil flow channel (L3) extends perpendicularly to the third main lubricating oil flow channel (P3) toward the third bearing (41), wherein the third lubricating oil flow channel has a third port (33) leading to the third bearing; and The fourth lubricating oil flow channel (L4) includes a fourth flow channel section (L41) extending perpendicularly to the third main lubricating oil flow channel (P3) toward the second housing, a fifth flow channel section (L42) extending in the second housing, and a sixth flow channel section (L43) extending perpendicularly to the fifth flow channel section toward the fourth bearing (42), wherein the sixth flow channel section has a fourth port (43) leading to the fourth bearing.

6. The hydrostatic transmission gearbox according to claim 5, characterized in that: A second throttle screw (33a) is provided in the third lubricating oil flow passage (L3); and A second through hole (2210) is provided at one end of the second flange (221) close to the fourth bearing (42). The second through hole is configured to be aligned with the fourth port (43) and has a size smaller than that of the fourth port.

7. The hydrostatic transmission gearbox according to claim 1 or 2, characterized in that: The hydrostatic transmission gearbox (100) further comprises an output shaft (5) having an output gear (Z), the output shaft being supported in the lower region of the housing chamber via a fifth bearing (51) away from the output gear and a sixth bearing close to the output gear, wherein the fifth bearing (51) is arranged in a bearing chamber (52) defined by a bearing seat housing (50); wherein an oil inlet hole (501) is provided on the upper side of the bearing seat housing and an oil drain hole (502) is provided on the lower side of the bearing seat housing, and the oil inlet hole and the oil drain hole are both in fluid communication with the bearing chamber.

8. The hydrostatic transmission gearbox according to claim 2, characterized in that: A first sealing ring (121) is provided at the joint between the first flange (211) and the second shell (12); and a second sealing ring (122) is provided at the joint between the first flow channel section (L21) and the second flow channel section (L22).

9. The hydrostatic transmission gearbox according to claim 5, characterized in that: A third sealing ring (123) is provided at the joint between the second flange (221) and the second shell (12); and a fourth sealing ring (124) is provided at the joint between the fourth flow channel section (L41) and the fifth flow channel section (L42).

10. An engineering machine, characterized in that: The construction machine comprises a hydrostatic transmission gearbox according to any one of claims 1 to 9.

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