Rear axle structure of a fork lift truck

Abstract

This invention discloses a rear axle structure for a forklift, relating to the field of forklift technology. It includes: a frame on which a steering unit is mounted, and a swing arm hinged to the rear of the frame; a drive wheel assembly located at the rear of the frame. The steering unit is connected to the drive wheel assembly to drive its rotation. When the vehicle turns, the steering unit drives the drive wheel assembly to rotate, and the drive wheel assembly, through a transmission assembly, drives the balance wheel assembly to rotate accordingly. The steering of the balance wheel assembly is actively transmitted by the drive wheel assembly, eliminating lateral forces caused by offset distance. This results in smooth vehicle steering, and the balance wheel assembly and drive wheel assembly maintain a defined relative position, making the parking state controllable and avoiding additional disturbances when restarting the vehicle. Furthermore, this invention requires only one steering unit to achieve synchronous steering of the drive wheel assembly and the balance wheel assembly, eliminating the need for a separate steering unit and controller for the balance wheel assembly, significantly reducing cost and structural complexity.

Description

Technical Field

[0001] This invention relates to the field of forklift technology, and more specifically to a rear axle structure for a forklift. Background Technology

[0002] As industrial material handling vehicles, forklifts' rear axle structure significantly impacts their steering performance, driving stability, and operational efficiency. Currently, forklift rear axle balance wheel structures primarily employ two technical solutions: First, using swivel casters as balance wheels. However, the offset between the swivel caster's rotation pivot point and the wheel's contact point generates lateral force during vehicle reversal, causing lateral swaying of the vehicle body. Furthermore, the swivel caster's stationary state is uncertain, generating additional disturbances upon restarting. Second, using an active steering mechanism to drive the balance wheels. This solution requires a separate steering unit and controller for the balance wheels, while the drive wheels themselves are equipped with steering units. This dual-system approach to steering control results in high cost, large space requirements, and complex control algorithms.

[0003] Therefore, there is an urgent need to propose a rear axle structure for forklifts. Summary of the Invention

[0004] In order to overcome the above-mentioned technical problems, the purpose of this invention is to provide a rear axle structure for a forklift.

[0005] The objective of this invention can be achieved through the following technical solutions: A rear axle structure for a forklift, comprising: A chassis on which a steering unit is mounted, and a swing frame is hinged to the rear of the chassis; A drive wheel assembly is located at the rear of the vehicle frame, and the steering unit is connected to the drive wheel assembly to drive the drive wheel assembly to rotate. A balance wheel assembly is disposed at the rear of the frame and is connected to the swing frame; A transmission assembly is connected between the drive wheel assembly and the balance wheel assembly, wherein the drive wheel assembly drives the balance wheel assembly to turn via the transmission assembly.

[0006] As a further aspect of the present invention: the steering unit enables the drive wheel assembly and the balance wheel assembly to achieve at least three states: in the first state, the drive wheel assembly is centered in the direction of vehicle travel, and the balance wheel assembly is parallel to the drive wheel assembly; in the second state, the drive wheel assembly deflects to the right, and the balance wheel assembly follows the drive wheel assembly to deflect to the right via the transmission assembly; in the third state, the drive wheel assembly deflects to the left, and the balance wheel assembly follows the drive wheel assembly to deflect to the left via the transmission assembly.

[0007] As a further aspect of the present invention: the drive wheel assembly and the balance wheel assembly are respectively provided with a first connector and a second connector on their sides; The transmission assembly includes a first connecting rod hinged to a first connecting member, a second connecting rod hinged to a second connecting member, and a transmission rod disposed between the first connecting rod and the second connecting rod. The two ends of the transmission rod are hinged to the ends of the first connecting rod and the second connecting rod, respectively, and the middle part of the transmission rod is hinged to the vehicle frame.

[0008] As a further aspect of the present invention: both the first connecting rod and the second connecting rod are semi-circular rings, and the transmission rod is bent.

[0009] As a further aspect of the present invention: the hinge points between the two ends of the transmission rod and the first connecting rod and the second connecting rod are respectively the first movable hinge point and the second movable hinge point; the hinge point between the first connecting rod and the first connecting member is the first fixed hinge point; the hinge point between the second connecting rod and the second connecting member is the second fixed hinge point; and the hinge point between the transmission rod and the vehicle frame is the third fixed hinge point.

[0010] As a further aspect of the present invention: the balance wheel assembly and the swing frame are hinged by a pin, a mounting bracket is fixedly connected to the frame, and a shock-absorbing spring is provided between the mounting bracket and the swing frame.

[0011] As a further aspect of the present invention: the first movable hinge point and the second movable hinge point are respectively provided with bearing holes at corresponding positions on the transmission rod; the first fixed hinge point, the second fixed hinge point and the third fixed hinge point are respectively provided with bearing holes at corresponding positions on the first connecting rod, the second connecting member and the middle of the transmission rod; a spherical bearing is installed in each of the bearing holes; a first flat washer is provided at both ends of each spherical bearing; a threaded hole is provided at another corresponding position of each of the first movable hinge point, the second movable hinge point, the first fixed hinge point, the second fixed hinge point and the third fixed hinge point; a screw passes through the spherical bearing; the screw passes through the bearing and the threaded hole in sequence and is threaded into the threaded hole; a second flat washer is fitted on the screw; the second flat washer is sandwiched between the screw head and one of the first flat washers.

[0012] As a further aspect of the present invention: the mounting bracket is threaded with an adjusting bolt, and the two ends of the shock-absorbing spring are respectively connected to the swing bracket and the adjusting bolt.

[0013] As a further aspect of the present invention, the steering center of the balance wheel assembly coincides with the ground contact point of its wheel.

[0014] As a further aspect of the present invention, the bearing bore of the spherical bearing is filled with grease.

[0015] The beneficial effects of this invention are as follows: The drive wheel assembly and the balance wheel assembly are arranged side by side at the rear of the vehicle frame. When the vehicle turns, the steering unit drives the drive wheel assembly to rotate, and the drive wheel assembly drives the balance wheel assembly to rotate accordingly through the transmission assembly. The steering of the balance wheel assembly is actively transmitted by the drive wheel assembly, rather than being passively rotated, which eliminates the lateral force caused by the offset distance. The vehicle steering is smooth, and the balance wheel assembly and the drive wheel assembly maintain a certain relative position, making the parking state controllable and avoiding additional disturbances when restarting the vehicle. In addition, this invention only requires one steering unit to achieve synchronous steering of the drive wheel assembly and the balance wheel assembly, eliminating the need to configure a separate steering unit and controller for the balance wheel assembly, which significantly reduces cost and structural complexity. Attached Figure Description

[0016] The invention will now be further described with reference to the accompanying drawings.

[0017] Figure 1 This is a rear view of the overall structure of the present invention; Figure 2 This is a bottom view of the invention in its first state; Figure 3 This is a bottom view of the invention in its second state; Figure 4 This is a bottom view of the invention in its third state; Figure 5 This is a schematic diagram of the connection of the spherical bearing of the present invention.

[0018] Explanation of reference numerals in the attached drawings: 1. Frame; 2. Steering unit; 3. Swing frame; 4. Drive wheel assembly; 5. Balance wheel assembly; 6. Transmission assembly; 61. First connecting member; 62. Second connecting member; 63. First link; 64. Second link; 65. Transmission rod; 601. First movable hinge point; 602. Second movable hinge point; 603. First fixed hinge point; 604. Second fixed hinge point; 605. Third fixed hinge point; 71. Bearing hole; 7. Spherical bearing; 72. First flat washer; 73. Threaded hole; 74. Second flat washer; 75. Screw; 31. Pin; 32. Mounting bracket; 33. Shock absorber spring; 34. Adjusting bolt. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] See Figures 1-2An embodiment of the present invention provides a rear axle structure for a forklift, comprising: a frame 1 on which a steering unit 2 is mounted, and a swing frame 3 hinged to the rear of the frame 1; a drive wheel assembly 4 disposed on the frame 1 and used to provide steering power, wherein the steering unit 2 is connected to the drive wheel assembly 4 to drive the drive wheel assembly 4 to rotate; a balance wheel assembly 5 disposed on the frame 1 and connected to the swing frame 3; and a transmission assembly 6 connected between the drive wheel assembly 4 and the balance wheel assembly 5, wherein the drive wheel assembly 4 drives the balance wheel assembly 5 to turn through the transmission assembly 6, wherein the drive wheel assembly 4 and the balance wheel assembly 5 are the drive wheel assembly and the balance wheel assembly of the forklift, respectively.

[0021] Specifically, the drive wheel assembly 4 and the balance wheel assembly 5 are arranged side by side at the rear of the frame 1. When the vehicle turns, the steering unit 2 drives the drive wheel assembly 4 to rotate, and the drive wheel assembly 4 drives the balance wheel assembly 5 to rotate through the transmission assembly 6. The steering of the balance wheel assembly 5 is actively transmitted by the drive wheel assembly 4, rather than passively rotating, which eliminates the lateral force caused by the offset distance. The vehicle steering is smooth, and the balance wheel assembly 5 and the drive wheel assembly 4 maintain a certain relative position. The parking state is controllable, which can avoid additional disturbances when restarting the vehicle. In addition, the present invention only requires one set of steering unit 2 to realize the synchronous steering of the drive wheel assembly 4 and the balance wheel assembly 5. There is no need to configure a separate steering unit 2 and controller for the balance wheel assembly 5, which significantly reduces the cost and structural complexity.

[0022] See Figures 1-4 Optionally, the steering unit 2 enables the drive wheel assembly 4 and the balance wheel assembly 5 to achieve at least three states: in the first state, the drive wheel assembly 4 is centered in the direction of vehicle travel, and the balance wheel assembly 5 is parallel to the drive wheel assembly 4; in the second state, the drive wheel assembly 4 deflects to the right, and the balance wheel assembly 5 follows the drive wheel assembly 4 to deflect to the right via the transmission assembly 6; in the third state, the drive wheel assembly 4 deflects to the left, and the balance wheel assembly 5 follows the drive wheel assembly 4 to deflect to the left via the transmission assembly 6.

[0023] In this embodiment, when the vehicle is traveling in a straight line, the steering unit 2 controls the drive wheel assembly 4 to be in the center position. At this time, the balance wheel assembly 5 remains parallel to the drive wheel assembly 4 under the action of the transmission assembly 6, ensuring that the vehicle travels stably in a straight line. When the vehicle needs to turn right, the steering unit 2 drives the drive wheel assembly 4 to turn to the right. The drive wheel assembly 4 transmits the steering action to the balance wheel assembly 5 through the transmission assembly 6, causing the balance wheel assembly 5 to turn to the right synchronously, achieving coordinated steering. When the vehicle needs to turn left, the steering unit 2 drives the drive wheel assembly 4 to turn to the left, and the balance wheel assembly 5 follows suit by turning to the left through the transmission assembly 6. By flexibly switching between these three states, precise steering control of the vehicle under different driving conditions is achieved. The following steering of the balance wheel assembly 5 effectively reduces steering resistance, improves steering stability, and effectively avoids the lateral swaying problem caused by passive steering of traditional omnidirectional wheels.

[0024] See Figures 1-4 Optionally, the drive wheel assembly 4 and the balance wheel assembly 5 are respectively provided with a first connecting member 61 and a second connecting member 62 on their sides; the transmission assembly 6 includes a first connecting rod 63 hinged to the first connecting member 61, a second connecting rod 64 hinged to the second connecting member 62, and a transmission rod 65 disposed between the first connecting rod 63 and the second connecting rod 64; the two ends of the transmission rod 65 are respectively hinged to the ends of the first connecting rod 63 and the second connecting rod 64, and the middle part of the transmission rod 65 is hinged to the frame 1.

[0025] In this embodiment, the first link 63, the second link 64, and the transmission rod 65 are all located on the same movable plane, which is parallel to the bottom of the vehicle. This saves space occupied by the transmission assembly 6 and avoids interference between the transmission assembly 6 and the ground. When the steering unit 2 drives the drive wheel assembly 4 to rotate, the drive wheel assembly 4 drives the first link 63 to rotate through the first connector 61, thereby driving the transmission rod 65 to rotate around its middle part. The transmission rod 65 drives the second link 64 to rotate, and the second link 64 drives the balance wheel assembly 5 to rotate through the second connector 62.

[0026] See Figures 2-4 Optionally, the first link 63 and the second link 64 are both semi-circular rings, and the transmission rod 65 is bent. The bent transmission rod 65 can be adapted to the structure of the frame 1 and the wheelbase, so that the two ends of the transmission rod 65 can form reasonable connection angles with the first link 63 and the second link 64 respectively.

[0027] See Figures 2-4 Optionally, the hinge points between the two ends of the transmission rod 65 and the first connecting rod 63 and the second connecting rod 64 are the first movable hinge point 601 and the second movable hinge point 602, respectively; the hinge point between the first connecting rod 63 and the first connecting member 61 is the first fixed hinge point 603; the hinge point between the second connecting rod 64 and the second connecting member 62 is the second fixed hinge point 604; and the hinge point between the transmission rod 65 and the frame 1 is the third fixed hinge point 605.

[0028] In this embodiment, the first fixed hinge point 603 and the second fixed hinge point 604 serve as the rotation fulcrum of the first connecting rod 63 and the second connecting rod 64, respectively, and the third fixed hinge point 605 serves as the rotation fulcrum of the transmission rod 65. The first movable hinge point 601 and the second movable hinge point 602 move in space with the steering action. Since the drive wheel assembly 4 and the balance wheel assembly 5 are staggered on both sides of the frame 1, the following angle of the balance wheel assembly 5 and the steering angle of the drive wheel assembly 4 are non-linearly related through the transmission assembly 6 to adapt to the actual vehicle steering.

[0029] It should be noted that in the first state, the first connecting member 61 and the second connecting member 62 are arranged opposite each other, the first fixed hinge point 603 and the second fixed hinge point 604 are opposite each other, and the first movable hinge point 601 and the second movable hinge point 602 are located on the left side of the drive wheel assembly 4 and the balance wheel assembly 5 (towards the front of the forklift); in the second state, the drive wheel assembly 4 deflects to the right in the direction of vehicle travel, and the first fixed hinge point 603 follows the rotation of the drive wheel assembly 4. Because the transmission rod 65 can rotate around the third fixed hinge point 605, the first movable hinge point 601 moves closer to the drive wheel assembly 4 from left to right through the first connecting rod 63, and at the same time, the second movable hinge point 602 moves away from the balance wheel assembly 5 from right to left through the transmission rod 65. Then, the second fixed hinge point 604 drives the balance wheel assembly 5 to deflect to the right through the second connecting rod 64.

[0030] In the third state, the drive wheel assembly 4 deflects to the left in the direction of vehicle movement. The first fixed hinge point 603 rotates with the drive wheel assembly 4. Since the transmission rod 65 can rotate around the third fixed hinge point 605, the first movable hinge point 601 moves away from the drive wheel assembly 4 from right to left through the first connecting rod 63. The second movable hinge point 602 moves closer to the balance wheel assembly 5 from left to right through the transmission rod 65. Then, the second fixed hinge point 604 drives the balance wheel assembly 5 to deflect to the left through the second connecting rod 64.

[0031] See Figure 1 Optionally, the balance wheel assembly 5 is hinged to the swing frame 3 via a pin 31, allowing it to swing only up and down. A mounting bracket 32 ​​is fixedly connected to the frame 1, and a shock-absorbing spring 33 is provided between the mounting bracket 32 ​​and the swing frame 3. The shock-absorbing spring 33 is arranged vertically, allowing the balance wheel assembly 5 to swing slightly around the pin 31. The shock-absorbing spring 33 serves to limit the swing amplitude and reduce shock.

[0032] See Figures 1-5Optionally, the first movable hinge point 601 and the second movable hinge point 602 are respectively provided with bearing holes 71 at corresponding positions on the transmission rod 65. The first fixed hinge point 603, the second fixed hinge point 604 and the third fixed hinge point 605 are respectively provided with bearing holes 71 at corresponding positions on the first connecting rod 63, the second connecting member 62 and the middle of the transmission rod 65. A spherical bearing 7 is installed in each bearing hole 71. A first flat washer 72 is provided at both ends of the spherical bearing 7. The first movable hinge point 601, the second movable hinge point 602, the first fixed hinge point 603, the second fixed hinge point 604 and the third fixed hinge point 605 are respectively provided with bearing holes 71 at corresponding positions on the first connecting rod 63, the second connecting member 62 and the middle of the transmission rod 65. A threaded hole 73 is provided at the other corresponding position of the hinge point 604 and the third fixed hinge point 605. A screw 75 is inserted into the spherical bearing 7. The screw 75 passes through the bearing and the threaded hole 73 in sequence and is threaded into the threaded hole 73. By tightening the screw 75 into the threaded hole 73, the component for installing the spherical bearing 7 is installed between the protruding head of the screw 75 and the component with the threaded hole 73. A second flat washer 74 is fitted on the screw 75. The second flat washer 74 is sandwiched between the head of the screw 75 and one of the first flat washers 72. The diameter of the first washer is smaller than the diameter of the second washer.

[0033] In this embodiment, the spherical bearing 7 has a self-aligning function, which can adapt to the angular deviation generated by the transmission component 6 during transmission, thereby reducing wear and preventing the swing of the balance wheel from affecting the stable operation of the transmission component 6. The arrangement of the first and second shims effectively disperses the pressure on the connecting surface and provides appropriate frictional damping for the screw 75 to prevent loosening of the connection.

[0034] See Figure 1 Optionally, an adjusting bolt 34 is threaded through the mounting bracket 32, and the two ends of the shock-absorbing spring 33 are connected to the swing frame 3 and the adjusting bolt 34 respectively. The distance between the two ends of the shock-absorbing spring 33 is adjusted by adjusting the adjusting bolt 34 to adjust the swing amplitude of the swing frame 3.

[0035] See Figure 1 Optionally, the steering center of the balance wheel assembly 5 coincides with the contact point of its wheel. Compared with the traditional forklift balance wheel which uses a universal wheel, the offset between the steering center and the contact point causes a large lateral impact force when changing direction, resulting in vehicle body swaying and tire wear. In addition, the direction is uncertain when parking and causes additional disturbances when starting. In this embodiment, when the vehicle turns, the balance wheel assembly 5 rotates around the contact point, which is less likely to generate lateral force caused by the offset. The parking state is certain and there is no additional disturbance when restarting, which significantly improves driving stability and operational safety. At the same time, it reduces abnormal tire wear and extends tire life.

[0036] Optionally, the bearing bore 71 of the spherical plain bearing 7 is filled with grease. During the operation of the transmission assembly 6, the grease forms an oil film on the friction surface, reducing direct metal-to-metal contact, lowering the coefficient of friction and wear rate, and also serving to seal, prevent dust and corrosion, and dissipate heat.

[0037] In the description of this invention, it should be understood that the terms "upper," "lower," "left," and "right," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or a specific orientational structure and operation. Therefore, they should not be construed as limitations on the invention. Furthermore, "first" and "second" are only for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "multiple" means two or more.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A rear axle structure for a forklift, characterized in that, include: A frame (1) on which a steering unit (2) is mounted, and a swing frame (3) is hinged to the rear of the frame (1). A drive wheel assembly (4) is disposed at the rear of the frame (1), and the steering unit (2) is connected to the drive wheel assembly (4) to drive the drive wheel assembly (4) to rotate; A balance wheel assembly (5) is disposed at the rear of the frame (1) and the balance wheel assembly (5) is connected to the swing frame (3); A transmission assembly (6) is connected between the drive wheel assembly (4) and the balance wheel assembly (5), wherein the drive wheel assembly (4) drives the balance wheel assembly (5) to turn through the transmission assembly (6).

2. The rear axle structure of the forklift according to claim 1, characterized in that, The steering unit (2) enables the drive wheel assembly (4) and the balance wheel assembly (5) to achieve at least three states: in the first state, the drive wheel assembly (4) is centered in the direction of vehicle movement, and the balance wheel assembly (5) is parallel to the drive wheel assembly (4); in the second state, the drive wheel assembly (4) deflects to the right, and the balance wheel assembly (5) follows the drive wheel assembly (4) to deflect to the right through the transmission assembly (6); in the third state, the drive wheel assembly (4) deflects to the left, and the balance wheel assembly (5) follows the drive wheel assembly (4) to deflect to the left through the transmission assembly (6).

3. The rear axle structure of the forklift according to claim 2, characterized in that, The drive wheel assembly (4) and the balance wheel assembly (5) are respectively provided with a first connector (61) and a second connector (62) on their sides. The transmission assembly (6) includes a first link (63) hinged to the first connector (61), a second link (64) hinged to the second connector (62), and a transmission rod (65) disposed between the first link (63) and the second link (64). The two ends of the transmission rod (65) are hinged to the ends of the first connecting rod (63) and the second connecting rod (64) respectively, and the middle part of the transmission rod (65) is hinged to the frame (1).

4. The rear axle structure of the forklift according to claim 3, characterized in that, The first connecting rod (63) and the second connecting rod (64) are both semi-circular rings, and the transmission rod (65) is bent.

5. The rear axle structure of the forklift according to claim 4, characterized in that, The hinge points between the two ends of the transmission rod (65) and the first connecting rod (63) and the second connecting rod (64) are the first movable hinge point (601) and the second movable hinge point (602), respectively. The hinge point between the first connecting rod (63) and the first connecting member (61) is the first fixed hinge point (603). The hinge point between the second connecting rod (64) and the second connecting member (62) is the second fixed hinge point (604). The hinge point between the transmission rod (65) and the frame (1) is the third fixed hinge point (605).

6. The rear axle structure of the forklift according to claim 5, characterized in that, The balance wheel assembly (5) is hinged to the swing frame (3) by a pin (31), and a mounting bracket (32) is fixedly connected to the frame (1). A shock-absorbing spring (33) is provided between the mounting bracket (32) and the swing frame (3).

7. The rear axle structure of the forklift according to claim 6, characterized in that, The first movable hinge point (601) and the second movable hinge point (602) are respectively provided with bearing holes (71) at corresponding positions on the transmission rod (65). The first fixed hinge point (603), the second fixed hinge point (604) and the third fixed hinge point (605) are respectively provided with bearing holes (71) at corresponding positions in the middle of the first connecting rod (63), the second connecting member (62) and the transmission rod (65). A spherical bearing (7) is installed in each of the bearing holes (71). A first flat washer (72) is provided at both ends of each spherical bearing (7). The first movable hinge point (601) is provided with bearing holes (71) at corresponding positions on the transmission rod (65). A threaded hole (73) is provided at the other corresponding position of the hinge point (601), the second movable hinge point (602), the first fixed hinge point (603), the second fixed hinge point (604) and the third fixed hinge point (605). A screw (75) is provided inside the joint bearing (7). The screw (75) passes through the bearing and the threaded hole (73) in sequence and is threaded into the threaded hole (73). A second flat washer (74) is provided on the screw (75). The second flat washer (74) is sandwiched between the head of the screw (75) and one of the first flat washers (72).

8. The rear axle structure of the forklift according to claim 6, characterized in that, The mounting bracket (32) is threaded with an adjusting bolt (34), and the two ends of the shock-absorbing spring (33) are connected to the swing bracket (3) and the adjusting bolt (34) respectively.

9. The rear axle structure of the forklift according to claim 1, characterized in that, The steering center of the balance wheel assembly (5) coincides with the ground contact point of its wheel.

10. The rear axle structure of the forklift according to claim 7, characterized in that, The bearing bore (71) of the spherical bearing (7) is filled with grease.

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