A wet friction overload clutch

Abstract

The utility model discloses a kind of wet friction overload clutches, including output shaft, the front section of output shaft is outer spline section, front pressure plate is installed on the front end face of outer spline section by internal hexagon screw, rear pressure plate is connected with outer spline section by internal spline, three friction plates are set between front pressure plate and rear pressure plate, friction plate is connected input torque by outer spline, one pair of plate is set between two adjacent friction plates, each pair of plate is contacted with two sides friction plate, front pressure plate and rear pressure plate are contacted with adjacent friction plate, elastic component includes disc spring, spring seat and adjusting pad and is installed in the rear end of rear pressure plate, stop washer is set between the shaft shoulder of outer spline section and compression nut, compression nut is abutted with stop washer, the overload clutch is not easy to deform in use, the stability of the contact surface between friction plate and pair of plate is guaranteed, assembly efficiency is high, compression nut is not easy to loosen, improve the reliability and service life of gear box.

Description

Technical Field

[0001] This utility model belongs to the field of clutch technology, and relates to a friction overload clutch, specifically a wet friction overload clutch. Background Technology

[0002] The feed box drive gearbox in a combine harvester is a crucial component of the transmission chain. During operation, it requires internal overload protection. Its main function is to transmit torque to drive the feed box via an overload clutch during normal operation. When an overload or jamming occurs at the feed load end, exceeding a set torque value, the overload clutch slips, separating the active and passive power transmission, thus protecting the engine and gearbox transmission chain from damage due to overload. However, existing wet friction overload clutches have the following problems:

[0003] 1. The front section of the output shaft of the overload clutch is machined with external splines. The entire structure of the overload clutch is axially positioned by machining a positioning shoulder on the front end of the external spline section of the output shaft. The positioning shoulder is small, and tightening it with a nut will cause the entire overload clutch to deform significantly. At the same time, the external spline of the output shaft must be machined by gear shaping, and a relief groove structure is required, which increases the machining cost.

[0004] 2. Due to the limited internal space of the gearbox, the pressure plate of the overload clutch is relatively thin. After the nut is tightened, the pressure plate will deform, resulting in a reduction in the contact area between the friction plate and the mating plate, and uneven surface pressure.

[0005] 3. Frictional torque is controlled by adjusting the normal force of the disc spring by adjusting the tightening torque of the nut. However, due to the non-linear stiffness of the disc spring, the compression height is different each time, and the tolerance of the nut is large, so the tightening torque control is not precise. It is necessary to measure the frictional torque multiple times after installation, and adjust the tightening torque of the nut only if it does not meet the requirements, resulting in low assembly efficiency.

[0006] 4. The nut is prevented from loosening by punching the convex thin wall into the groove of the output shaft. During operation, the loosening of the nut is very harmful, which will lead to the attenuation of friction torque and abnormal torque transmission of the gearbox. Therefore, the nut is the key to the effective operation of the overload clutch, and it is unreliable to use only one method. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide a wet friction overload clutch that can solve the technical problems of large overall deformation, uneven surface pressure between friction plates and mating plates, low assembly efficiency, and easy loosening of nuts in existing overload clutches.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] A wet friction overload clutch includes an output shaft. The front section of the output shaft is an external spline section with external splines machined on it. Three friction plates, two mating plates, a rear bearing plate, and an elastic component are fitted on the external spline section. A front bearing plate is installed at the front end of the external spline section, and a clamping nut is installed at the rear end of the external spline section.

[0010] The front bearing plate is mounted on the front end face of the external spline section by multiple circumferentially distributed hexagonal socket screws. The rear bearing plate is connected to the external spline section by an internal spline. Three friction plates are disposed between the front and rear bearing plates. The friction plates are connected by external splines to input torque. A mating plate is disposed between two adjacent friction plates. The mating plate is connected to the external spline section by an internal spline. Each mating plate is in contact with the friction plates on both sides. Both the front and rear bearing plates are in contact with adjacent friction plates. The elastic component is mounted on the rear end of the rear bearing plate and is in contact with the rear bearing plate. The front end face of the clamping nut abuts against the shoulder end face of the external spline section.

[0011] This utility model also includes the following technical features:

[0012] The elastic component includes a disc spring, a spring seat, and an adjusting shim. The spring seat is located at the rear end of the rear pressure plate, the disc spring is mounted on the spring seat, and the outer edge of the disc spring contacts the rear end face of the rear pressure plate. The adjusting shim is located between the spring seat and the clamping nut, and the thickness of the adjusting shim is used to adjust the positive pressure of the disc spring.

[0013] The output shaft is also fitted with a stop washer, which is located between the shoulder of the outer spline section and the clamping nut. The inner ring of the stop washer has a pair of symmetrically arranged forward-bent fixing ears. The output shaft near the shoulder of the outer spline section has a pair of fixing grooves corresponding to the fixing ears. The pair of fixing ears are inserted into the pair of fixing grooves. The outer skirt of the stop washer wraps around the hexagonal edge of the clamping nut.

[0014] The outer diameters of the front bearing plate, the mating plate, and the rear bearing plate are the same.

[0015] The thickness of the front bearing plate is 9mm.

[0016] The thickness of the rear bearing plate is 4mm.

[0017] The thickness of the adjustment pad is 0.8 to 1.3 mm.

[0018] Compared with the prior art, this utility model has the following technical effects:

[0019] (I) This utility model replaces the positioning shoulder with a front bearing plate, and the external spline can be machined by gear hobbing, which improves the processing efficiency and saves processing costs. The increased thickness of the front and rear bearing plates improves the overall rigidity of the clutch, avoids large deformation of the whole, ensures the stability of the contact surface between the friction plate and the mating plate, and solves the problem of uneven surface pressure caused by the compression deformation of the friction plate.

[0020] (II) By adding an adjustment shim, the positive pressure of the disc spring can be controlled by selecting an adjustment shim of appropriate thickness during assembly, eliminating the need for precise control of the tightening torque of the clamping nut and improving assembly efficiency.

[0021] (III) The stop washer added in this utility model can prevent the clamping nut from loosening during operation, ensure the transmission of maximum torque, improve the life of the friction plate, and enhance the reliability and service life of the gearbox. Attached Figure Description

[0022] Figure 1 This is an exploded view of the overall structure of this utility model.

[0023] Figure 2 This is a cross-sectional view of the overall structure of this utility model.

[0024] The meanings of the labels in the diagram are as follows:

[0025] 1. Output shaft, 2. Friction plate, 3. Couple plate, 4. Rear bearing plate, 5. Elastic component, 6. Front bearing plate, 7. Compression nut, 8. Socket head screw, 9. Stop washer, 11. External spline section, 12. Fixing groove, 51. Disc spring, 52. Spring seat, 53. Adjusting shim, 91. Fixing lug.

[0026] The specific content of this utility model will be further explained in detail below with reference to the embodiments. Detailed Implementation

[0027] Following the above technical solution, the following are specific embodiments of this utility model. It should be noted that this utility model is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solution of this application fall within the protection scope of this utility model.

[0028] In this utility model, unless otherwise stated, directional terms such as "upper", "lower", "left", and "right" are generally defined based on the drawing in the corresponding figure; "inner" and "outer" refer to the inner and outer contours of the corresponding components; and "longitudinal", "transverse", and "vertical" refer to the directions marked in the figure.

[0029] Example:

[0030] This embodiment provides a wet friction overload clutch, such as Figures 1 to 2 As shown, it includes an output shaft 1. The front section of the output shaft 1 is an external spline section 11 with external splines machined on it. Three friction plates 2, two mating plates 3, a rear bearing plate 4 and an elastic component 5 are mounted on the external spline section 11. A front bearing plate 6 is installed at the front end of the external spline section 11, and a clamping nut 7 is installed at the rear end of the external spline section 11.

[0031] The front bearing plate 6 is mounted on the front end face of the external spline section 11 by multiple circumferentially distributed internal hexagon screws 8. The rear bearing plate 4 is connected to the external spline section 11 by internal splines. Three friction plates 2 are arranged between the front bearing plate 6 and the rear bearing plate 4. The friction plates 2 are connected to the input torque by external splines. A mating plate 3 is arranged between two adjacent friction plates 2. The mating plate 3 is connected to the external spline section 11 by internal splines. Each mating plate 3 is in contact with the friction plates 2 on both sides. The front bearing plate 6 and the rear bearing plate 4 are both in contact with the adjacent friction plates 2. The elastic component 5 is installed at the rear end of the rear bearing plate 4 and is in contact with the rear bearing plate 4. The front end face of the clamping nut 7 abuts against the shoulder end face of the external spline section 11.

[0032] In this embodiment, a front bearing plate 6 is installed at the front end of the external spline section 11 to replace the machining of the positioning shoulder on the external spline section 11. The external spline can be machined by gear hobbing, which improves machining efficiency and saves machining costs. Furthermore, the thickness of the front bearing plate 6 is increased to 9mm, which improves the rigidity of the overall clutch and prevents large deformation after compression, ensuring the stability of the contact surface between the friction plate 2 and the mating plate 3, and solving the problem of uneven surface pressure caused by the compression deformation of the friction plate 2. The addition of a rear bearing plate 4, with a thickness of 4mm, prevents warping deformation when the elastic component 5 presses against the rear bearing plate 4, further ensuring... The stability of the contact surface between friction plate 2 and mating plate 3 is ensured, so that the normal pressure of elastic component 5 is fully transmitted to friction plate 2. The torque is transmitted through the friction torque between friction plate 2 and mating plate 3. When the torque does not exceed the friction torque generated by friction plate 2, it can work normally. When the output end of output shaft 1 is overloaded or jammed, and the transmitted torque exceeds the friction torque generated by friction plate 2, the two will slip. When slipping, friction plate 2 and mating plate 3 slide relative to each other, generating a lot of heat. The gearbox adopts splash lubrication. After the gear lubricating oil is injected, the lower part of friction plate 2 is immersed in the lubricating oil, which can effectively dissipate heat.

[0033] As a preferred embodiment, the front bearing plate 6, the mating plate 3, and the rear bearing plate 4 have the same outer diameter, which further ensures the rigidity of the overall clutch and improves product quality.

[0034] As a preferred embodiment, the elastic component 5 includes a disc spring 51, a spring seat 52, and an adjusting shim 53. The spring seat 52 is located at the rear end of the rear pressure plate 4, and the disc spring 51 is mounted on the spring seat 52. The outer edge of the disc spring 51 contacts the rear end face of the rear pressure plate 4. The clutch generates positive pressure by deforming the disc spring 51, which presses the friction plate 2 to generate friction torque. The adjusting shim 53 is located between the spring seat 52 and the clamping nut 7. The positive pressure of the disc spring 51 can be adjusted by adjusting the thickness of the adjusting shim 53. The thickness of the adjusting shim 53 is in the range of 0.8 to 1.3 mm. After selecting an adjusting shim 53 of appropriate thickness, it is not necessary to precisely control the tightening torque of the clamping nut 7 to adjust the positive pressure of the disc spring 51, thus improving assembly efficiency.

[0035] As a preferred embodiment, a retaining washer 9 is added and fitted onto the output shaft 1. The retaining washer 9 is positioned between the shoulder of the outer spline section 11 and the clamping nut 7. The inner ring of the retaining washer 9 has a pair of symmetrically arranged forward-bent fixing ears 91. The output shaft 1 near the shoulder of the outer spline section 11 has a pair of fixing grooves 12 corresponding to the fixing ears. The pair of fixing ears 91 are inserted into the pair of fixing grooves 12. The front end face of the outer skirt of the retaining washer 9 is in contact with the end face of the shoulder of the outer spline section 11. The clamping nut 7 is tightened to the rear end face of the outer skirt of the retaining washer 9. By processing, the outer skirt of the retaining washer 9 is bent towards the clamping nut 7, so that the outer skirt of the retaining washer 9 wraps around the hexagonal edge of the clamping nut 7, preventing the clamping nut 7 from loosening during operation. If the clamping nut 7 loosens due to vibration or other reasons during operation, the compression of the disc spring 51 will decrease, and the friction torque will decrease. The maximum torque that can be transmitted will attenuate, which may lead to failure and inability to transmit the designed maximum torque. The number of slippages during operation will increase, reducing the life of the friction plate 2. Adding the retaining washer 7 can ensure that the clamping nut 7 will not loosen, improving the reliability and service life of the gearbox.

[0036] In actual operation of this embodiment:

[0037] The front bearing plate 6 is fixed to the front end face of the outer spline section 11 by eight hexagon socket screws 8. Then, the friction plate 2 and the mating plate 3 are placed in sequence. The first friction plate 2 contacts the front bearing plate 6, and the third friction plate 2 contacts the rear bearing plate 4. Then, the disc spring 51 and the spring seat 52 are installed. The thickness of the adjusting shim 53 is initially selected and assembled. The two pre-bent fixing ears 91 of the stop washer 9 are inserted into the corresponding fixing grooves 12 of the output shaft 1. The clamping nut 7 is tightened to the rear end face of the outer skirt of the stop washer 9. Then, the entire device is placed on a special fixture to measure the friction torque. The thickness of the adjusting shim 53 is increased or decreased according to the first measurement result. The stop washer 9 and the clamping nut 7 are reinstalled. The friction torque value is tested for the second time. If it meets the requirements, it is acceptable. Finally, the outer skirt of the stop washer 9 is folded onto the hexagonal edge of the clamping nut 7, and the two fixing ears 91 are punched into the fixing grooves 12 to prevent the clamping nut 7 from loosening during operation.

Claims

1. A wet friction overload clutch, comprising an output shaft (1), the front section of which is an external spline section (11) machined with external splines, characterized in that, The external spline segment (11) is fitted with three friction plates (2), two mating plates (3), a rear bearing plate (4) and an elastic component (5). The front bearing plate (6) is installed at the front end of the external spline segment (11), and the clamping nut (7) is installed at the rear end of the external spline segment (11). The front bearing plate (6) is installed on the front end face of the external spline section (11) by a plurality of circumferentially distributed internal hexagonal screws (8). The rear bearing plate (4) is connected to the external spline section (11) by internal splines. Three friction plates (2) are arranged between the front bearing plate (6) and the rear bearing plate (4). The friction plates (2) are connected to the input torque by external splines. A mating plate (3) is arranged between two adjacent friction plates (2). The mating plate (3) is connected to the external spline section (11) by internal splines. Each mating plate (3) is in contact with the friction plates (2) on both sides. The front bearing plate (6) and the rear bearing plate (4) are both in contact with the adjacent friction plates (2). The elastic component (5) is installed at the rear end of the rear bearing plate (4) and is in contact with the rear bearing plate (4). The front end face of the clamping nut (7) abuts against the shoulder end face of the external spline section (11).

2. The wet friction overload clutch as described in claim 1, characterized in that, The elastic component (5) includes a disc spring (51), a spring seat (52), and an adjusting pad (53). The spring seat (52) is located at the rear end of the rear bearing plate (4). The disc spring (51) is mounted on the spring seat (52). The outer edge of the disc spring (51) contacts the rear end face of the rear bearing plate (4). The adjusting pad (53) is located between the spring seat (52) and the clamping nut (7). The thickness of the adjusting pad (53) is used to adjust the magnitude of the positive pressure of the disc spring (51).

3. The wet friction overload clutch as described in claim 1, characterized in that, The output shaft (1) is also fitted with a stop washer (9). The stop washer (9) is located between the shoulder of the outer spline section (11) and the clamping nut (7). The inner ring of the stop washer (9) is provided with a pair of symmetrically arranged forward-bent fixing ears (91). The output shaft (1) near the shoulder of the outer spline section (11) is provided with a pair of fixing grooves (12) corresponding to the fixing ears. The pair of fixing ears (91) are inserted into the pair of fixing grooves (12). The outer skirt of the stop washer (9) wraps around the hexagonal edge of the clamping nut (7).

4. The wet friction overload clutch as described in claim 1, characterized in that, The front bearing plate (6), the mating plate (3), and the rear bearing plate (4) have the same outer diameter.

5. The wet friction overload clutch as described in claim 1, characterized in that, The thickness of the front bearing plate (6) is 9mm.

6. The wet friction overload clutch as described in claim 1, characterized in that, The thickness of the rear bearing plate (4) is 4mm.

7. The wet friction overload clutch as described in claim 2, characterized in that, The thickness of the adjustment pad (53) is 0.8 to 1.3 mm.

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