Gearbox for engineering machinery and engineering machinery

Abstract

The utility model relates to a gearbox for engineering machinery. The gearbox comprises a gearbox body (1), a clutch (2) housed within the gearbox housing and having a clutch shaft (20) having a first end (21) and an opposite second end (22); the speed change valve (3) is fixedly mounted to the gearbox body, the speed change valve is provided with a valve body, the valve body is provided with a circular groove (4) facing the gearbox body, and the second end of the clutch shaft extends into the circular groove; and a bushing (5) having a first section (6) of a first outer diameter and a second section (7) of a second outer diameter, the first outer diameter being greater than the second outer diameter, the bushing being mounted such that the first section is located between the second end of the clutch shaft and the gearbox housing and is in interference fit with the gearbox housing, and the second section is located between the second end of the clutch shaft and the gearbox housing. And the second section is located between the inner peripheral wall (40) of the circular groove and the second end of the clutch shaft. The utility model further relates to engineering machinery comprising the gearbox.

Description

TECHNICAL FIELD

[0001] The utility model relates to gearbox technical field especially relates to a kind of gearbox for engineering machinery / working machine, and the engineering machinery comprising the gearbox. BACKGROUND

[0002] For the shaft arranged with clutch in gearbox, two oil channels need to be introduced, one is pressure oil for gear shifting control, and the other is lubricating oil for lubricating friction plate and bearing.

[0003] The current implementation is that gearbox valve group is directly arranged at shaft end, and the oil entering valve group is divided into pressure oil and lubricating oil, and then enters shaft through shaft sleeve. Although this scheme can realize function and simplify arrangement, it still has the following problems: shaft sleeve and valve are interference assembled, and the matching section is almost the entire length of shaft sleeve, which can cause the inner circle of shaft sleeve to be greatly deformed after assembly, and the diameter tolerance and roundness are difficult to maintain in the state before assembly, thereby affecting the sealing effect of sealing ring on shaft; as a wear part, shaft sleeve needs to be easily disassembled, and the interference matching of long section is difficult to disassemble; the gap range of shaft sleeve and shaft is required to be high for the shaft end sealing ring to achieve good sealing effect, which requires high-precision positioning of valve and box body, and it is difficult to process the stopper directly due to the irregular shape of valve. SUMMARY

[0004] In order to overcome at least one aspect of the above problems, it is necessary to provide a gearbox for engineering machinery, which is not only compact in structure and good in sealing effect, but also easy to disassemble.

[0005] Therefore, the utility model provides a gearbox for engineering machinery, comprising: a gearbox housing; a clutch accommodated in the gearbox housing and having a clutch shaft with a first end and an opposite second end; a gear shift valve fixedly installed to the gearbox housing and having a valve body with a circular groove facing the gearbox housing, the second end of the clutch shaft extending into the circular groove; and a shaft sleeve including a through hole, a first section having a first outer diameter, and a second section having a second outer diameter, the first outer diameter being larger than the second outer diameter, wherein the shaft sleeve is installed such that the first section is located between the second end of the clutch shaft and the gearbox housing and interference fits with the gearbox housing, and the second section is located between the inner peripheral wall of the circular groove and the second end of the clutch shaft.

[0006] In the above scheme, the shaft sleeve is provided as a wear part to avoid direct valve replacement due to wear, which is beneficial to save maintenance cost. Moreover, the first section of the shaft sleeve interference fits with the gearbox housing, the matching section is short, and the distance from the through hole is far, so that the deformation of the inner diameter after assembly is small, which is helpful for sealing.

[0007] According to a preferred embodiment of the present invention, a first annular groove and two first annular sealing grooves located on both sides of the second section of the bushing are provided in the outer peripheral wall, and at least one opening is provided in the first annular groove, and a first sealing ring, such as an O-ring, is arranged in each of the two first annular sealing grooves.

[0008] In a preferred embodiment of this utility model, the first section of the bushing has a first end face facing the second section and a second end face facing away from the second section, as well as a plurality of set screw holes extending axially between the first end face and the second end face. The set screw holes on the end face of the bushing allow screws to be driven in to hold the inner ring of the bearing during disassembly, and the bushing also serves as a wear-bearing component, facilitating disassembly.

[0009] In one embodiment, the circular groove also has a bottom wall, wherein the inner peripheral wall has a pressure oil outlet and the bottom wall has a lubricating oil outlet; the second outer diameter of the second section of the bushing is selected such that the outer peripheral surface of the second section is clearance-fitted with the inner peripheral wall of the circular groove; and there is a gap between the shaft end face of the second end of the clutch shaft and the bottom wall.

[0010] In one embodiment of the present invention, the clutch shaft has a pressure oil passage and a lubricating oil passage extending from the first end toward the second end and sealed apart from each other; the lubricating oil outlet is in fluid communication with the lubricating oil passage, and the pressure oil outlet is in fluid communication with the pressure oil passage; and wherein the lubricating oil inlet of the lubricating oil passage is located in the shaft end face;

[0011] According to a preferred embodiment of this utility model, a second annular groove and two second annular sealing grooves located on both sides of the second annular groove are formed in the outer peripheral wall of the second end of the clutch shaft. The pressure oil inlet of the pressure oil channel is located in the second annular groove, and a second sealing ring, such as a rectangular sealing ring, is arranged in each of the two second annular sealing grooves. This configuration ensures that the pressure oil flowing out from the pressure oil outlet will not enter the gap between the shaft end face and the bottom wall of the second end of the clutch shaft, further avoiding the risk of oil leakage.

[0012] In an advantageous embodiment, the pressure oil outlet is aligned with the first annular groove of the bushing, and at least one opening of the bushing is aligned with the second annular groove of the clutch shaft, thereby enabling fluid communication between the pressure oil outlet and the pressure oil inlet. Preferably, four openings are provided in the first annular groove, evenly distributed circumferentially along the bushing. It should be understood that the number of openings described above is merely exemplary, and other numbers of openings are also covered within the scope of this application.

[0013] According to a preferred embodiment of this invention, the gearbox further includes bearings, such as tapered bearings, respectively arranged at both ends of the clutch shaft; the clutch shaft has a shoulder near the second end, wherein the bearing arranged at the second end of the clutch shaft is located between the second end face of the bushing and the shoulder; and an adjusting shim is provided between the second end face and the bearing for adjusting the bearing clearance. Here, the first section of the bushing serves to position the bearing, and the bearing bears the axial force, directly pressing against the second end face of the first section of the bushing, saving the need for a commonly used bearing end cap. Preferably, the second end face can be constructed as a stepped surface to facilitate bearing assembly.

[0014] According to a preferred embodiment of the present invention, the plurality of set screw holes include two or three set screw holes evenly arranged along the circumference of the bushing to ensure the stability, adjustability and long-term reliability of the bushing.

[0015] This utility model also provides an engineering machine, which includes the above-mentioned gearbox.

[0016] The beneficial effects of the gearbox according to this utility model are at least as follows: the bushing and the gearbox housing are interference fit, the fitting section is relatively short and the distance from the inner circle (the bushing through hole) is relatively far, the deformation of the inner diameter after assembly is very small, which helps to seal; the bushing end face has a set screw hole, and when disassembling, a bolt is driven in to hold the bearing inner ring, and the bushing acts as a wear-bearing component, which facilitates disassembly; the shaft end seal ring achieves a good sealing effect, which requires a high clearance range between the bushing and the clutch shaft. Using the outer circle of the bushing as a positioning stop facilitates machining and ensures the positional accuracy of the bushing, without needing to ensure the positional accuracy of the transmission valve.

[0017] With the above-described configuration according to this utility model, the gearbox has a compact structure, and the lubricating oil enters the lubricating oil passage on the clutch shaft directly from the lubricating oil outlet of the transmission valve, and the pressurized oil enters the pressurized oil passage on the clutch shaft directly from the pressurized oil outlet of the transmission valve, thus eliminating the need for oil pipes or external oil passages, reducing costs and the risk of oil leakage.

[0018] By modifying the valve body structure of the transmission valve to provide clutch oil inlet and bearing positioning, the transmission valve is directly mounted onto the gearbox housing, resulting in a compact structure, reduced manufacturing difficulty and cost, and lower risk of oil leakage. Specifically, by incorporating a fluid channel within the transmission valve body that directly communicates with both lubricating oil and pressure oil channels, additional oil pipes and external channels are eliminated, reducing costs and leakage risks. Furthermore, the larger diameter section of the bushing also serves to position the bearing, eliminating the need for a commonly used bearing end cap. Attached Figure Description

[0019] The features and advantages of this utility model will become clear from the following detailed description provided with reference to the accompanying drawings. It should be understood that the following drawings are merely schematic and not necessarily drawn to scale, and therefore should not be considered as limitations on this utility model, wherein:

[0020] Figure 1 A perspective view of one embodiment of a gearbox for engineering machinery according to the present invention is shown;

[0021] Figure 2 for Figure 1 The cross-sectional view of the gearbox shown;

[0022] Figure 3 for Figure 2 A partially enlarged view of the cross-sectional view of the gearbox shown;

[0023] Figure 4 This is a structural schematic diagram of an embodiment of the bushing according to the present invention; and

[0024] Figure 5 for Figure 4 The cross-sectional view of the bushing of the speed change valve shown. Detailed Implementation

[0025] Embodiments of the present invention are described below with reference to the accompanying drawings. Numerous specific details are set forth in the following description to enable those skilled in the art to more fully understand and implement the present invention. Furthermore, it should be understood that the present invention is not limited to the specific embodiments described. Rather, the present invention can be practiced with any combination of the features and elements described below, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments, and advantages are for illustrative purposes only and should not be construed as elements or limitations of the claims unless expressly set forth in the claims.

[0026] The terms "first" and "second" are used below to describe the elements of this application. These terms are used only to distinguish the individual elements and not to limit the nature, order, or number of these elements. The terms "comprising" and "having" are used to indicate an open-ended inclusion and mean that there may be additional elements / components besides those listed.

[0027] Figure 1 An embodiment of a gearbox / transmission for engineering machinery according to the present invention is shown. Figure 2 This is a cross-sectional view of the gearbox. For clarity, parts unrelated to the improvements in this application have been omitted.

[0028] See Figure 1 and Figure 2The gearbox 100 includes a gearbox housing 1, a clutch 2 housed within the gearbox housing 1, and a transmission valve 3 fixedly mounted to the gearbox housing 1. The clutch 2 has a clutch shaft 20 with a first end 21 and an opposing second end 22, and a pressure oil passage 23 and a lubricating oil passage 24 extending from the first end toward the second end, the pressure oil passage and the lubricating oil passage being arranged substantially parallel and sealedly spaced apart. Additionally, a bearing 10, such as a tapered bearing, is provided at both the first end 21 and the second end 22 to support the clutch shaft 20.

[0029] In this embodiment, the transmission valve 3 can be directly mounted to the gearbox housing 1 using, for example, threaded fasteners. Figure 2 and Figure 3 As can be seen, the transmission valve 3 has a valve body 30, which has an oil inlet port (not shown) and a circular groove 4. The end of the valve body 30 facing the gearbox housing 1 is defined as the connecting end, and the circular groove 4 is located at this connecting end. The oil inlet port is located at other parts of the valve body. The circular groove 4 includes a bottom wall 41 with a lubricating oil outlet (not shown) and an inner peripheral wall 40 with a pressure oil outlet 401. The lubricating oil outlet can be, for example, circular, and the pressure oil outlet 401 can be a slender, approximately elliptical shape. In addition, an opening is provided at a position on the gearbox housing 1 opposite to the transmission valve 3. The second end 22 of the clutch shaft 20 extends through this opening into the circular groove 4 of the valve body 30, and the wall of the opening can form a bearing seat for the bearing 10.

[0030] In the above embodiment, it is advantageous to provide a bushing 5 as a wear-bearing component within the circular groove 4. The bushing 5 includes a through hole 50, a first section 6 having a first outer diameter, and a second section 7 having a second outer diameter, the first outer diameter being larger than the second outer diameter. The bushing 5 is fitted onto the clutch shaft 20 via the through hole 50, and is installed such that the first section 6 is located between the second end 22 of the clutch shaft 20 and the gearbox housing 1, and is in an interference fit with the gearbox housing 1. The second section 7 is located between the inner peripheral wall 40 of the circular groove 4 and the second end 22 of the clutch shaft 20. In this invention, the length of the second section 7 is significantly greater than the length of the first section 6.

[0031] In a preferred embodiment, see Figure 4 and Figure 5The second section 7 of the bushing 5 has a first annular groove 71 and two first annular sealing grooves 72 located on both sides of the first annular groove 71. The first annular groove 71 has at least one opening 74, such as four openings evenly distributed along the circumference of the bushing. First sealing rings 720, such as O-rings, are arranged in the two first annular sealing grooves 72 to provide static sealing for the bushing and the transmission valve. By providing such a bushing, direct wear of the sealing rings on the valve body can be avoided, thus avoiding direct valve replacement due to valve body failure. If necessary, only the bushing can be replaced, thereby saving maintenance costs. Furthermore, by making the first section of the bushing interference fit with the gearbox housing, the mating section is short, and the distance to the through hole is far, resulting in minimal deformation of the inner diameter after assembly, which aids in sealing.

[0032] In a preferred embodiment, the first segment 6 of the bushing 5 has a first end face 61 facing the second segment 7 and a second end face 62 facing away from the second segment, and a plurality of set screw holes 63 extending axially between the first end face and the second end face, for example, two set screw holes arranged circumferentially at an angle of 180°, or three set screw holes arranged circumferentially at an angle of 120°. By providing such set screw holes on the end face of the bushing, bolts can be driven in to hold the inner ring of the bearing during disassembly, facilitating disassembly.

[0033] See you again Figure 3 When the transmission valve 3 is assembled into the gearbox housing 1, there is a gap between the shaft end face 220 of the second end 22 of the clutch shaft 20 and the bottom wall 41 of the circular groove 4, and the lubricating oil passage is open at the shaft end face to form a lubricating oil inlet 241. Due to the gap, even if the lubricating oil outlet is not aligned with the lubricating oil inlet 241 as shown in the figure, the lubricating oil outlet can still be in fluid communication with the lubricating oil passage 24. During normal operation, the lubricating oil from the lubricating oil outlet can always enter the lubricating oil passage 24 through the gap and the lubricating oil inlet 241. Preferably, the second outer diameter of the second section 7 of the bushing 5 is selected such that the outer peripheral surface of the second section is in clearance fit with the inner peripheral wall 40 of the circular groove 4.

[0034] In an advantageous embodiment, a sealing structure is provided at the end of the pressure oil passage 23 near the second end 22 of the clutch shaft 20, and a second annular groove 200 and two second annular sealing grooves 221 located on both sides of the second annular groove 200 are provided in the outer peripheral wall of the second end 22 of the clutch shaft 20. The pressure oil inlet 231 of the pressure oil passage 23 is located in the second annular groove, and a second sealing ring 222 is arranged in each of the two annular grooves, which is, for example, a sealing ring with a rectangular cross-section, and serves as a dynamic seal for the clutch shaft and bushing.

[0035] Advantageously, in the assembled state, the pressure oil outlet 401 is aligned with the first annular groove 71 of the bushing 5, and at least one opening 74 of the bushing is aligned with the second annular groove 200 of the clutch shaft 20, so that the pressure oil outlet 401 is in fluid communication with the pressure oil inlet 231, and thus the pressure oil outlet 401 can be in fluid communication with the pressure oil passage 23. This allows the pressure oil from the pressure oil outlet 401 to directly enter the pressure oil passage in the clutch shaft, and then enter the clutch piston chamber, without leaking the gap between the shaft end face 220 of the second end 22 of the clutch shaft 20 and the bottom wall 41 of the circular groove 4. This also makes the pressure oil passage 23 and the lubricating oil passage 24, which are separated from each other, seal each other.

[0036] Here, by improving the structure of the valve body of the transmission valve, especially the flow path layout of the pressure oil and lubricating oil, the pressure oil and lubricating oil can directly enter the pressure oil passage and lubricating oil passage in the clutch shaft from the transmission valve, respectively, eliminating the need for oil pipes and external oil passages, reducing costs and the risk of oil leakage.

[0037] According to a preferred embodiment of the present invention, the clutch shaft 20 has a shoulder 223 near the second end 22, wherein the bearing 10 disposed at the first end of the clutch shaft is located between the second end face 62 of the first section of the bushing 5 and the shoulder 223, thereby the bushing 5, especially the first section 6 of the bushing, is used to position the bearing 10 (more specifically the outer ring of the bearing 10 in the illustrated embodiment), which bears axial force and presses directly against the second end face of the bushing, saving the use of a commonly used bearing end cap. Advantageously, an adjusting shim 60 is provided between the second end face 62 and the bearing 10 for adjusting the bearing clearance, thereby ensuring the bearing clearance.

[0038] In this utility model, an engineering machine is also provided, which includes the above-mentioned gearbox. The engineering machine can be a grader, a loader, a bulldozer or a road roller, especially various engineering machines with gearboxes.

[0039] Industrial applicability

[0040] The gearbox according to this utility model can be applied to a variety of engineering machinery, such as graders, loaders, bulldozers or road rollers.

[0041] The following is combined with Figure 2 and Figure 3 A brief introduction to the assembly and operation process of the gearbox for engineering machinery according to this utility model:

[0042] After the main body of the gearbox is assembled, the clutch shaft 20 is exposed. First, the rectangular second sealing ring 222 is placed in the two second annular sealing grooves 221 respectively. Then, the bushing 5 is assembled onto the gearbox housing 1, using the first section 6 of the bushing 5 as a stop for positioning. Next, the circular first sealing ring 720 is placed in the two first annular sealing grooves 72. Finally, the transmission valve 3 is assembled onto the gearbox housing 1.

[0043] When it is necessary to perform gear shifting operation on clutch 2, the transmission valve 3 is switched to shifting mode. Pressure oil from pressure oil outlet 401 enters the first annular groove 71 of bushing 5, and then enters the second annular groove 200 located on clutch shaft 20 through opening 74. Subsequently, it is introduced into pressure oil passage 23 in clutch shaft 20 through pressure oil inlet 231. Then, the pressure oil enters the piston chamber of clutch through pressure oil outlet to drive the piston of clutch to move in piston chamber.

[0044] During normal operation, since the friction plates of clutch 2 and the bearings 10 at both ends of clutch shaft 20 always need lubrication, lubricating oil from the lubricating oil outlet is always introduced into the lubricating oil passage 24 of clutch shaft through lubricating oil inlet 241, and then the lubricating oil reaches the friction plates to lubricate them, and at the same time enters the bearings 10 at both ends of clutch shaft to lubricate them.

[0045] In the gearbox according to this utility model, by providing a bushing as a wear-resistant component, direct valve replacement due to wear is avoided, which helps save maintenance costs. Furthermore, by making the first section of the bushing interference fit with the gearbox housing, the mating section is short, and the distance from the through hole is far, resulting in minimal deformation of the inner diameter after assembly, which aids in sealing. Additionally, a set screw hole is provided on the end face of the bushing, allowing bolts to be driven in to hold the bearing inner ring during disassembly, facilitating removal; using the outer circle of the bushing as a locating stop facilitates machining and ensures the positional accuracy of the bushing, eliminating the need to guarantee the positional accuracy of the transmission valve.

[0046] Various modifications and variations can be made to the embodiments disclosed above without departing from the scope or spirit of this invention. Other embodiments of this invention will be apparent to those skilled in the art based on the practice of this invention disclosed in this specification. This specification and the examples disclosed herein should be considered illustrative only, and the true scope of this invention is defined by the appended claims and their equivalents.

Claims

1. A gearbox for a working machine, the gearbox (100) comprising: a gearbox housing (1); a clutch (2) housed within the gearbox housing (1) and having a clutch shaft (20) with a first end (21) and an opposite second end (22); a gear shift valve (3) fixedly mounted to the gearbox housing and having a valve body (30) with a circular recess (4) facing the gearbox housing, the second end of the clutch shaft extending into the circular recess; and a bushing (5) comprising a through hole (50), a first section (6) having a first outer diameter and a second section (7) having a second outer diameter, the first outer diameter being larger than the second outer diameter, wherein the bushing is mounted such that the first section is located between the second end (22) of the clutch shaft and the gearbox housing (1) and is in interference fit with the gearbox housing, the second section being located between an inner peripheral wall (40) of the circular recess and the second end (22) of the clutch shaft.

2. The gearbox according to claim 1, wherein an outer peripheral wall (70) of the second section (7) of the bushing (5) is provided with a first annular groove (71) and two first annular sealing grooves (72) located on both sides of the first annular groove, and at least one aperture (74) is provided in the first annular groove (71), and a first sealing ring (720) is arranged in each of the two first annular sealing grooves (72).

3. The gearbox according to claim 1 or 2, wherein the first section (6) of the bushing (5) has a first end face (61) facing the second section (7), a second end face (62) facing away from the second section, and a plurality of tumbler holes (63) extending axially between the first end face and the second end face.

4. The gearbox according to claim 2, wherein the circular recess (4) further has a bottom wall (41), wherein the inner peripheral wall (40) is provided with a pressure oil outlet (401), and the bottom wall (41) is provided with a lubricating oil outlet; the second outer diameter of the second section (7) of the bushing (5) is selected such that an outer peripheral surface of the second section is in clearance fit with the inner peripheral wall (40) of the circular recess; and an axial end face (220) of the second end (22) of the clutch shaft (20) has a clearance with the bottom wall (41).

5. The gearbox according to claim 4, wherein the clutch shaft (20) has a pressure oil channel (23) and a lubricating oil channel (24) extending from the first end towards the second end and being sealedly separated from each other; the lubricating oil outlet is in fluid communication with the lubricating oil channel (24), and the pressure oil outlet (401) is in fluid communication with the pressure oil channel (23); and wherein a lubricating oil inlet (241) of the lubricating oil channel (24) is located in the axial end face.

6. The gearbox according to claim 5, wherein A second annular groove (200) and two second annular sealing grooves (221) are formed in the outer peripheral wall of the second end (22) of the clutch shaft (20), wherein the pressure oil inlet (231) of the pressure oil passage (23) is located in the second annular groove, and a second sealing ring (222) is arranged in each of the two second annular sealing grooves (221).

7. The gearbox according to claim 6, characterized in that, the pressure oil outlet (401) is aligned with the first annular groove (71) of the shaft sleeve, and the at least one aperture (74) of the shaft sleeve is aligned with the second annular groove of the clutch shaft, so that the pressure oil outlet (401) is in fluid communication with the pressure oil inlet (231).

8. The gearbox according to claim 1 or 2, characterized in that, the gearbox further comprises bearings (10) arranged at the two ends of the clutch shaft (20) respectively; the clutch shaft has a shaft shoulder (223) close to the second end (22), wherein the bearing (10) arranged at the second end of the clutch shaft is located between the second end face (62) of the shaft sleeve and the shaft shoulder; and an adjusting washer (60) is arranged between the second end face and the bearing for adjusting the bearing play.

9. The gearbox of claim 3, wherein, The plurality of jackscrew holes (63) includes two or three jackscrew holes arranged uniformly along the circumference of the shaft sleeve.

10. A working machine, characterized in that The engineering machinery comprises the gearbox according to any one of claims 1 to 9.

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