Forklift steering axle easy to maintain

Abstract

The forklift steering axle easy to maintain comprises a steering axle body, a steering knuckle, a steering hub, a connecting rod and a steering oil cylinder, and double fixing plates are arranged at the end of the steering axle body and fixed to rotating shafts on the two sides of the steering knuckle through tapered roller bearings respectively. The two ends of the tapered roller bearing are provided with an oil injection port and an oil outlet and are respectively provided with an oil cup and a roller bearing oil seal; one end of the connecting rod is installed on the U-shaped hinged front forks and the front fork pin shafts of output shafts at the two ends of the steering oil cylinder through knuckle bearings, knuckle bearing oil seals are installed in gaps between the two end faces of the knuckle bearings and the U-shaped hinged front forks, and a third oil injection opening penetrating to the knuckle bearings is formed in one end of the connecting rod. According to the forklift steering axle easy to maintain, the design is ingenious, the structure is compact, in the high-pressure oil injection maintenance process, old grease in a system is pushed out, meanwhile, the oil seal is protected against being extruded out of a steering system in the high-pressure state, the sealing effect is good, the maintenance efficiency is high, the maintenance cost is low, and operation is easy.

Description

Technical Field

[0001] The invention relates to the technical field of forklift steering axles, in particular to an easy-to-maintain forklift steering axle. Background Art

[0002] With the rapid development of industrial vehicles, industrial vehicles are involved in various fields and working environments. How to improve the service life of various vehicle parts is a challenge, and the good and sufficient maintenance and sealing of the vehicle are also related to the performance and service life of the vehicle.

[0003] In recent years, the steering axles of domestic forklifts, especially the structures and sealing systems in the steering system, are similar. However, the most prominent problem of this common steering structure and sealing system is that it is inconvenient to maintain. For example, when injecting new grease into the steering structure, when the oil pressure injected by the equipment is too low, the amount of new oil injected is small, and the old grease in the steering structure cannot be pushed out, thus failing to achieve the expected maintenance effect; but when the oil pressure injected by the equipment is too high, the seals in the steering structure will be pushed out, thereby destroying the sealing system in the entire steering system. However, if you want to completely replace the grease in the steering system, you can only replace the new grease by disassembling the various parts of the steering system in the steering axle, which leads to slow maintenance efficiency and high maintenance costs. How to solve the problem of complete injection of new oil and pushing out old oil without damaging the sealing system during maintenance of the steering structure in the steering axle is a difficult problem that the entire industry urgently needs to overcome. Summary of the invention

[0004] The purpose of the present invention is to provide a forklift steering axle that is easy to maintain to solve the above defects.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A forklift steering axle that is easy to maintain, comprising a steering axle body, a steering knuckle, a steering wheel hub, a connecting rod, and a steering oil cylinder. The steering knuckles are provided with two and are respectively mounted at both ends of the steering axle body through a rotating shaft. The steering wheel hubs are provided with two and are respectively mounted at the outer ends of the two steering knuckles. The connecting rods are provided with two, one end of the two connecting rods is respectively hinged to the output shafts at both ends of the steering oil cylinder, and the other end thereof is respectively hinged to the two steering knuckles; the steering knuckle sleeve is fixed on the rotating shaft, and double fixing plates are provided at the ends of the steering axle body and are both connected by tapered rollers. The sub-bearings are respectively fixed on the rotating shafts on both sides of the steering knuckle, and oil filling ports and oil outlets are arranged at both ends of the tapered roller bearing, and oil cups and roller bearing oil seals are respectively installed; U-shaped articulated front forks are arranged on the output shafts at both ends of the steering cylinder and a front fork pin is installed through them, one end of the connecting rod is installed on the front fork pin inside the U-shaped articulated front fork through a joint bearing, joint bearing oil seals are installed at the gaps between the two end surfaces of the joint bearing and the U-shaped articulated front fork, and an oil filling port three is arranged on one end of the connecting rod and passes through the joint bearing.

[0007] Preferably, the double fixing plates are an upper fixing plate and a lower fixing plate which are parallel to each other and are vertically fixed to the end of the steering bridge body, and shaft fixing end plates are fixedly installed at both ends of the rotating shaft.

[0008] Preferably, annular oil storage space 1 and annular oil storage space 2 are respectively arranged between the upper fixed plate and the outer wall of the rotating shaft at the inner and outer ends of the tapered roller bearing at the upper fixed plate; the oil filling port and the oil outlet port at both ends of the tapered roller bearing at the upper fixed plate are oil filling port 1 and oil outlet port 1 respectively, the oil filling port 1 and the oil outlet port 1 are both arranged on the upper fixed plate and penetrate into the annular oil storage space 1 and the annular oil storage space 2 respectively, the oil cup is installed in the oil filling port 1, the roller bearing oil seal is installed in the annular oil storage space 2, and a wire retaining ring is installed in the oil outlet port 1.

[0009] Preferably, an oil storage space three and an annular oil storage space four are respectively arranged between the lower fixed plate and the outer wall of the rotating shaft at the inner and outer ends of the tapered roller bearing at the lower fixed plate; the oil filling port and the oil outlet port at both ends of the tapered roller bearing at the lower fixed plate are oil filling port two and oil outlet port two, respectively, the oil filling port two is arranged on the shaft fixed end plate and passes through the oil storage space three, and the oil cup is installed in the oil filling port two; the oil outlet port two is located in the gap between the steering knuckle and the lower fixed plate and passes through the annular oil storage space four, the roller bearing oil seal is installed in the annular oil storage space four, and a dust cover is installed in the oil outlet port two.

[0010] Preferably, the roller bearing oil seal is an annular structure consisting of a metal frame and a rubber wrapping layer, the metal frame is arranged in the middle of the rubber wrapping layer; the end of the metal frame is tightly attached to the upper fixed plate or the lower fixed plate, and the rubber wrapping layer is provided with a double annular sealing lip and is tightly attached to the steering knuckle.

[0011] Preferably, a step blocking structure is provided on the lower fixed plate at the end of the steering bridge body at the roller bearing oil seal, and a metal frame of the roller bearing oil seal is engaged with the step blocking structure of the lower fixed plate.

[0012] Preferably, the spherical bearing oil seal is an annular structure consisting of an L-shaped hard frame and a rubber elastic layer, and the rubber elastic layer is arranged on the top and inner end surface of the L-shaped hard frame.

[0013] Preferably, the rubber elastic layer is provided with a three-lip sealing structure, namely annular sealing lip one, annular sealing lip two and annular sealing lip three. The annular sealing lip one is located at the top of the L-shaped hard skeleton and is tightly attached to the inner side surface of the U-shaped hinged front fork of the steering cylinder, the annular sealing lip two is located at the inner end face of the L-shaped hard skeleton and is tightly attached to the side end face of the connecting rod, and the annular sealing lip three is located at the inner end face of the L-shaped hard skeleton and is tightly attached to the end face of the joint bearing.

[0014] The beneficial effects of the present invention are:

[0015] The easy-to-maintain forklift steering axle of the present invention has a steering axle body fixed on the steering knuckle through a tapered roller bearing, and an oil filling port and an oil outlet are provided at both ends of the tapered roller bearing, and an oil cup and a roller bearing oil seal are installed respectively; the connecting rod is installed in the U-shaped hinged front fork of the steering oil cylinder through a spherical bearing, and the gaps between the two end surfaces of the spherical bearing and the U-shaped hinged front fork are both provided with spherical bearing oil seals, and an oil filling port three that runs through the spherical bearing is provided, which solves the problem that the old grease in the system is pushed out during the high-pressure oil filling maintenance process, and protects the oil seal from being squeezed out of the steering system under a high-pressure state, thereby avoiding damage to the entire sealing system; at the same time, new oil is directly injected under high pressure to push out the old oil, thereby improving the maintenance efficiency and reducing the maintenance cost. The easy-to-maintain forklift steering axle of the present invention has an ingenious design and a compact structure, and the old grease in the system is pushed out during the high-pressure oil filling maintenance process, and the oil seal is protected from being squeezed out of the steering system under a high-pressure state, and has a good sealing effect, high maintenance efficiency, low maintenance cost, and is easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 : A structural front view of the present invention;

[0017] Figure 2 : Figure 1 Structural cross-section view in the AA direction;

[0018] Figure 3 : Figure 3 A magnified view of the structure at D in the middle;

[0019] Figure 4 : Figure 3Enlarged view of the structure at E in the middle;

[0020] Figure 5 : Figure 3 A magnified view of the structure at F in the middle;

[0021] Figure 6 : Figure 3 A magnified view of the structure at G in the middle;

[0022] Figure 7 : A top view of the structure of the present invention;

[0023] Figure 8 : Figure 1 A magnified view of the structure at C in the middle;

[0024] Fig. 9 : Figure 2 Structural cross-section view in the middle BB direction;

[0025] Fig.10 : Fig. 9 Enlarged view of the structure at H in the middle. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0027] Embodiment 1:

[0028] Reference Figure 1-10 The present invention proposes an easy-to-maintain forklift steering axle, which includes a steering axle body 1, a steering knuckle 2, a steering wheel hub 3, a connecting rod 4, and a steering cylinder 5. Two steering knuckles 2 are provided and are respectively installed at both ends of the steering axle body 1 through a rotating shaft 11. Two steering wheel hubs 3 are provided and are respectively installed at the outer ends of the two steering knuckles 2. Two connecting rods 4 are provided. One end of the two connecting rods 4 is respectively hinged to the output shafts at both ends of the steering cylinder 5, and the other end thereof is respectively hinged to the two steering knuckles 2.

[0029] like Figure 1-6 As shown, the steering knuckle 2 is sleeved and fixed on the rotating shaft 7, and a double fixing plate is arranged at the end of the steering bridge body 1 and is respectively fixed to the rotating shaft 7 on both sides of the steering knuckle 2 through tapered roller bearings 71. Oil filling ports and oil outlets are arranged at both ends of the tapered roller bearing 71, and an oil cup 6 and a roller bearing oil seal 72 are respectively installed.

[0030] like Figure 1 , Figure 7-10As shown, a U-shaped hinged front fork 51 is provided on the output shafts at both ends of the steering cylinder 5 and a front fork pin 52 is installed through it, one end of the connecting rod 4 is installed on the front fork pin 52 inside the U-shaped hinged front fork 51 through a joint bearing 53, joint bearing oil seals 54 are installed in the gaps between the two end surfaces of the joint bearing 53 and the U-shaped hinged front fork 51, and an oil filling port 55 that penetrates through the joint bearing 53 is provided on one end of the connecting rod 4.

[0031] The invention provides an easy-to-maintain forklift steering axle, which solves the problem that old grease in the system is pushed out during high-pressure oil injection maintenance, while protecting the oil seal from being squeezed out of the steering system under high pressure, thereby avoiding damage to the entire sealing system; at the same time, new oil is directly injected under high pressure to push out old oil, thereby improving maintenance efficiency and reducing maintenance costs.

[0032] Embodiment 2:

[0033] Reference Figure 1-10 The present invention proposes an easy-to-maintain forklift steering axle, which includes a steering axle body 1, a steering knuckle 2, a steering wheel hub 3, a connecting rod 4, and a steering cylinder 5. Two steering knuckles 2 are provided and are respectively installed at both ends of the steering axle body 1 through a rotating shaft 11. Two steering wheel hubs 3 are provided and are respectively installed at the outer ends of the two steering knuckles 2. Two connecting rods 4 are provided. One end of the two connecting rods 4 is respectively hinged to the output shafts at both ends of the steering cylinder 5, and the other end thereof is respectively hinged to the two steering knuckles 2.

[0034] like Figure 1-6 As shown, the steering knuckle 2 is sleeved and fixed on the rotating shaft 7, and a double fixing plate is arranged at the end of the steering bridge body 1 and is respectively fixed to the rotating shaft 7 on both sides of the steering knuckle 2 through tapered roller bearings 71. Oil filling ports and oil outlets are arranged at both ends of the tapered roller bearing 71, and an oil cup 6 and a roller bearing oil seal 72 are respectively installed.

[0035] like Figure 1 , 2 As shown in FIG. 3 , the double fixing plates are an upper fixing plate 11 and a lower fixing plate 12 which are parallel to each other and are vertically fixed to the end of the steering bridge body 1 , and shaft fixing end plates 74 are fixedly installed at both ends of the rotating shaft 7 .

[0036] like Figure 3 , 4As shown, an annular oil storage space 1 75 and an annular oil storage space 2 76 are respectively provided between the upper fixing plate 11 and the outer wall of the rotating shaft 7 at the inner and outer ends of the tapered roller bearing 71 at the upper fixing plate 11. The oil filling port and the oil outlet at both ends of the tapered roller bearing 71 at the upper fixing plate 11 are respectively an oil filling port 111 and an oil outlet 112. The oil filling port 111 and the oil outlet 112 are both provided on the upper fixing plate 11 and penetrate into the annular oil storage space 1 75 and the annular oil storage space 2 76 respectively. The oil cup 6 is installed in the oil filling port 111, the roller bearing oil seal 72 is installed in the annular oil storage space 2 76, and a wire retaining ring 13 is installed in the oil outlet 112.

[0037] exist Figure 3 In the figure, the red arrows are the lines for injecting new oil and discharging old oil. Figure 3 As shown, the oil cup 6 is used to inject oil into the oil injection port 111 at high pressure, and the new lubricating oil passes through the oil injection port 111 and the annular oil storage space 175 in sequence to lubricate the tapered roller bearing 71, while the old lubricating oil is squeezed by the new lubricating oil and enters the annular oil storage space 276, the roller bearing oil seal 72 and the oil outlet 112 in sequence from the tapered roller bearing 71. The setting of the roller bearing oil seal 72 and the wire retaining ring 13 solves the problem that the old grease in the system is pushed out during the high-pressure oil injection maintenance process, while protecting the oil seal from being squeezed out of the steering system under high pressure, thereby avoiding damage to the entire sealing system; at the same time, the new oil is directly injected at high pressure to push out the old oil, thereby improving the maintenance efficiency and reducing the maintenance cost.

[0038] like Figure 5 , 6 As shown, an oil storage space 3 77 and an annular oil storage space 4 78 are respectively arranged between the lower fixed plate 12 and the outer wall of the rotating shaft 7 at the inner and outer ends of the tapered roller bearing 71 at the lower fixed plate 12. The oil storage space 3 77 is a cylindrical structure space formed by the annular space at the outer end of the tapered roller bearing 71 and the end space at the outer end of the rotating shaft 7. The oil filling port and the oil outlet at both ends of the tapered roller bearing 71 at the lower fixed plate 12 are respectively the oil filling port 2 741 and the oil outlet 2 79. The oil filling port 2 741 is arranged on the shaft fixed end plate 74 and penetrates into the oil storage space 3 77. The oil cup 6 is installed in the oil filling port 2 741; the oil outlet 2 79 is located in the gap between the steering knuckle 2 and the lower fixed plate 12 and penetrates into the annular oil storage space 4 78. The roller bearing oil seal 72 is installed in the annular oil storage space 4 78, and a dust cover 791 is installed in the oil outlet 2 79.

[0039] like Figure 6 As shown, the lower fixed plate 12 at the end of the steering bridge body 1 is provided with a step blocking structure 121 at the roller bearing oil seal 72 , and the metal frame 721 of the roller bearing oil seal 72 is engaged with the step blocking structure 121 of the lower fixed plate 12 .

[0040] exist Figure 5 In the figure, the red arrows are the lines for injecting new oil and discharging old oil. Figure 5 , 6 As shown, the oil cup 6 is used to inject oil into the second oil injection port 741 under high pressure, and the new lubricating oil passes through the second oil injection port 741 and the third oil storage space 77 in sequence to lubricate the tapered roller bearing 71, while the old lubricating oil is squeezed by the new lubricating oil and enters the fourth annular oil storage space 78, the roller bearing oil seal 72 and the second oil outlet 79 from the tapered roller bearing 71 in sequence to be discharged. The setting of the roller bearing oil seal 72 and the step blocking structure 121 solves the problem that the old grease in the system is pushed out during the high-pressure oil injection maintenance process, while protecting the oil seal from being squeezed out of the steering system under high pressure, thereby avoiding damage to the entire sealing system; at the same time, the new oil is directly injected under high pressure to push out the old oil, thereby improving the maintenance efficiency and reducing the maintenance cost.

[0041] The roller bearing oil seal 72 is an annular structure consisting of a metal frame 721 and a rubber wrapping layer 722. The metal frame 721 is arranged in the middle of the rubber wrapping layer 722. The end of the metal frame 721 is closely attached to the upper fixing plate 11 or the lower fixing plate 12. The rubber wrapping layer 722 is provided with a double annular sealing lip and closely attached to the steering knuckle 2. During the maintenance process of filling the steering system with new lubricating oil, the old oil is quickly squeezed out from the oil seal lip while the new oil is injected into the steering system. In this way, each component of the steering system is fully lubricated, thereby increasing the service life of each component of the steering system.

[0042] like Figure 1 , Figure 7-10 As shown, a U-shaped hinged front fork 51 is provided on the output shafts at both ends of the steering cylinder 5 and a front fork pin 52 is installed through it, one end of the connecting rod 4 is installed on the front fork pin 52 inside the U-shaped hinged front fork 51 through a joint bearing 53, joint bearing oil seals 54 are installed in the gaps between the two end surfaces of the joint bearing 53 and the U-shaped hinged front fork 51, and an oil filling port 55 that penetrates through the joint bearing 53 is provided on one end of the connecting rod 4.

[0043] The spherical bearing oil seal 54 is an annular structure composed of an L-shaped hard frame 541 and a rubber elastic layer 542 . The rubber elastic layer 542 is arranged on the top and inner end surface of the L-shaped hard frame 541 .

[0044] The rubber elastic layer 542 is provided with a three-lip sealing structure, which are an annular sealing lip 1 543, an annular sealing lip 2 544 and an annular sealing lip 3 545. The annular sealing lip 1 543 is located at the top of the L-shaped hard frame 541 and is closely attached to the inner side surface of the U-shaped hinged front fork 51 of the steering oil cylinder 5. The annular sealing lip 2 544 is located at the inner end surface of the L-shaped hard frame 541 and is closely attached to the side end surface of the connecting rod 4. The annular sealing lip 3 545 is located at the inner end surface of the L-shaped hard frame 541 and is closely attached to the end surface of the joint bearing 53. The three-lip sealing structure has a good sealing effect. During the high-pressure oil injection maintenance process, the old grease in the system is pushed out, and the joint bearing oil seal 54 is not squeezed out of the steering system under high pressure, avoiding damage to the entire sealing system.

[0045] The invention provides an easy-to-maintain forklift steering axle, which solves the problem that old grease in the system is pushed out during high-pressure oil injection maintenance, while protecting the oil seal from being squeezed out of the steering system under high pressure, thereby avoiding damage to the entire sealing system; at the same time, new oil is directly injected under high pressure to push out old oil, thereby improving maintenance efficiency and reducing maintenance costs.

[0046] The above is an exemplary description of the invention in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as such non-substantial improvements are made by adopting the method concept and technical solution of the present invention, or the concept and technical solution of the invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. An easy-to-maintain forklift steering axle, comprising a steering axle body (1), a steering knuckle (2), a steering wheel hub (3), a connecting rod (4), and a steering oil cylinder (5), wherein two steering knuckles (2) are provided and are respectively mounted on two ends of the steering axle body (1) through a rotating shaft (11), two steering wheel hubs (3) are provided and are respectively mounted on the outer ends of the two steering knuckles (2), two connecting rods (4) are provided, one end of the two connecting rods (4) is respectively hinged to the output shafts at both ends of the steering oil cylinder (5), and the other end thereof is respectively hinged to the two steering knuckles (2); characterized in that: The steering knuckle (2) is sleeved and fixed on the rotating shaft (7); a double fixing plate is arranged at the end of the steering bridge body (1) and is respectively fixed to the rotating shaft (7) on both sides of the steering knuckle (2) through tapered roller bearings (71); an oil filling port and an oil outlet are arranged at both ends of the tapered roller bearing (71), and an oil cup (6) and a roller bearing oil seal (72) are respectively installed; a U-shaped articulated front fork (51) is arranged on the output shaft at both ends of the steering cylinder (5) and a front fork pin shaft (52) is installed through it; one end of the connecting rod (4) is installed on the front fork pin shaft (52) inside the U-shaped articulated front fork (51) through a joint bearing (53); a joint bearing oil seal (54) is installed at the gap between the two end surfaces of the joint bearing (53) and the U-shaped articulated front fork (51); and one end of the connecting rod (4) is provided with an oil filling port three (55) that penetrates to the joint bearing (53).

2. The easy-to-maintain forklift steering axle according to claim 1, characterized in that: The double fixing plates are an upper fixing plate (11) and a lower fixing plate (12) which are parallel to each other and are vertically fixed to the end of the steering bridge body (1). Both ends of the rotating shaft (7) are fixedly mounted with shaft fixing end plates (74).

3. The easy-to-maintain forklift steering axle according to claim 2, characterized in that: An annular oil storage space 1 (75) and an annular oil storage space 2 (76) are respectively arranged between the upper fixing plate (11) and the outer wall of the rotating shaft (7) at the inner and outer ends of the tapered roller bearing (71) at the upper fixing plate (11); the oil filling port and the oil outlet port at the two ends of the tapered roller bearing (71) at the upper fixing plate (11) are respectively an oil filling port 1 (111) and an oil outlet port 1 (112); the oil filling port 1 (111) and the oil outlet port 1 (112) are both arranged on the upper fixing plate (11) and penetrate into the annular oil storage space 1 (75) and the annular oil storage space 2 (76); the oil cup (6) is installed in the oil filling port 1 (111); the roller bearing oil seal (72) is installed in the annular oil storage space 2 (76); and a wire retaining ring (13) is installed in the oil outlet port 1 (112).

4. The easy-to-maintain forklift steering axle according to claim 3, characterized in that: An annular oil storage space four (78) and an oil storage space three (77) are respectively arranged between the lower fixed plate (12) and the outer wall of the rotating shaft (7) at the inner and outer ends of the tapered roller bearing (71) at the lower fixed plate (12); the oil filling port and the oil outlet port at the two ends of the tapered roller bearing (71) at the lower fixed plate (12) are respectively an oil filling port two (741) and an oil outlet port two (79); the oil filling port two (741) is arranged on the shaft fixed end plate (74) and penetrates into the oil storage space three (77); the oil cup (6) is installed in the oil filling port two (741); the oil outlet port two (79) is located in the gap between the steering knuckle (2) and the lower fixed plate (12) and penetrates into the annular oil storage space four (78); the roller bearing oil seal (72) is installed in the annular oil storage space four (78), and a dust cover (791) is installed in the oil outlet port two (79).

5. The easy-to-maintain forklift steering axle according to claim 4, characterized in that: The roller bearing oil seal (72) is an annular structure consisting of a metal frame (721) and a rubber wrapping layer (722), wherein the metal frame (721) is arranged in the middle of the rubber wrapping layer (722); the end of the metal frame (721) is tightly attached to an upper fixing plate (11) or a lower fixing plate (12), and the rubber wrapping layer (722) is provided with a double annular sealing lip and is tightly attached to the steering knuckle (2).

6. The easy-to-maintain forklift steering axle according to claim 5, characterized in that: The lower fixed plate (12) at the end of the steering bridge body (1) is provided with a step blocking structure (121) at the roller bearing oil seal (72), and the metal frame (721) of the roller bearing oil seal (72) is engaged with the step blocking structure (121) of the lower fixed plate (12).

7. The easy-to-maintain forklift steering axle according to claim 1, characterized in that: The spherical bearing oil seal (54) is an annular structure consisting of an L-shaped hard frame (541) and a rubber elastic layer (542), wherein the rubber elastic layer (542) is arranged on the top end and the inner end surface of the L-shaped hard frame (541).

8. The easy-to-maintain forklift steering axle according to claim 7, characterized in that: The rubber elastic layer (542) is provided with a three-lip sealing structure, namely an annular sealing lip one (543), an annular sealing lip two (544) and an annular sealing lip three (545). The annular sealing lip one (543) is located at the top end of the L-shaped hard frame (541) and is tightly attached to the inner side surface of the U-shaped hinged front fork (51) of the steering cylinder (5). The annular sealing lip two (544) is located at the inner end surface of the L-shaped hard frame (541) and is tightly attached to the side end surface of the connecting rod (4). The annular sealing lip three (545) is located at the inner end surface of the L-shaped hard frame (541) and is tightly attached to the end surface of the joint bearing (53).

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