Sliding bearing for a rack and pinion oscillating cylinder

Abstract

The utility model relates to a sliding bearing for gear and rack swing cylinder, including bearing shell, the inside of bearing shell can be provided with gear shaft body of rotation, still be equipped with a plurality of cylinder barrels on bearing shell, the inside of every two coaxial cylinder barrels and the inside of bearing shell intercommunication, the inside of every two coaxial cylinder barrels and the inside of bearing shell still be equipped with rack body through the sliding of hydraulic oil drive, the tooth on rack body and the tooth on gear shaft body mesh, the inside of bearing shell still be equipped with the support bushing of coaxial center between adjacent cylinder barrel, be equipped with the lubricating grease on every support bushing and the side wall of support bushing is attached to the side wall of rack body, the utility model adopts the rack and piston structure and tin bronze support bushing of split type, provides a kind of gear and rack swing cylinder, which eliminates gear shaft radial load, output torque is big, running is stable, and it is not sensitive to processing and assembly error, and the service life of gear and rack swing cylinder is long.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic cylinder technology, specifically to a sliding bearing for a gear and rack swing hydraulic cylinder. Background Technology

[0002] A double-gear rack and pinion oscillating cylinder is a hydraulic actuator that converts hydraulic energy into finite-angle rotary motion. Its core structure consists of two parallel shafts with gears and a rack and piston that mesh with both within a sealed cylinder housing. When pressurized oil enters one end of the cylinder, it pushes the rack and piston in a linear motion, while the rack synchronously drives the two gears to rotate in opposite directions, thus transmitting a high-torque oscillating motion through the output shaft.

[0003] Authorization number CN110469554B discloses a double rack swing cylinder. According to its specification and drawings, the design uses oil pipes to connect the upper left oil hole, lower left oil hole, lower right oil hole, and upper right oil hole on the cylinder bottom and the housing. When the equipment is in use, the equipment is connected to a motor, and the output shaft of the motor is connected to the inner ring of the gear through a spline. The first oil guide hole and the second oil guide hole are connected to the equipment to be connected. Hydraulic fluid is injected into the cylinder, and the output shaft of the motor drives the gear to rotate, so that the gear drives the two racks to move laterally.

[0004] However, this design has certain limitations: the enormous radial force generated by the meshing of the gear and rack is usually borne by polymer guide belts mounted on the pistons at both ends of the rack. However, as the system's output torque demand continues to increase, the resulting radial force also increases accordingly. This requires the guide belts to have a wider contact area to distribute the load, which leads to a significant increase in the radial dimensions of the piston and the entire cylinder, making the structure bulky and presenting a design bottleneck. Summary of the Invention

[0005] This invention addresses the aforementioned shortcomings of the piston in a double rack and pinion swing cylinder during sliding. It proposes a sliding bearing for the rack and pinion swing cylinder, employing a split rack and piston structure and tin bronze support bearing. This provides a rack and pinion swing cylinder that eliminates radial load on the gear shaft, delivers high output torque, operates smoothly, is insensitive to machining and assembly errors, and has a long service life.

[0006] The objective of this invention is achieved through the following technical solution: a sliding bearing for a gear and rack oscillating cylinder, comprising a bearing housing, a gear shaft body rotatably disposed inside the bearing housing, and a plurality of cylinders disposed on the bearing housing, wherein the interior of every two coaxial cylinders is connected to the interior of the bearing housing, and a rack body that is pushed and slid by hydraulic oil is disposed inside the interior of every two coaxial cylinders and the interior of the bearing housing, wherein the teeth on the rack body mesh with the teeth on the gear shaft body, and a support bearing bush coaxial with the adjacent cylinders is disposed inside the bearing housing, each support bearing bush being provided with grease and the sidewall of the support bearing bush being in contact with the sidewall of the rack body, and a gap being present between the sidewall of each rack body and the inner wall of the cylinder.

[0007] Preferably, each of the rack bodies includes an annular portion and a rack portion. The annular portion of the rack body fits against the side wall of the support bearing. The teeth on the rack portion mesh with the teeth on the gear shaft body. The support bearing is made of tin bronze. The support bearing has an inner groove on the side near the annular portion, and the inner groove is filled with grease.

[0008] Preferably, the bearing housing has a plurality of first annular inner grooves, the same number as the number of support bearing bushes, with one side of each support bearing bush coaxially installed inside the first annular inner groove, and the other side of each support bearing bush fitting against the side wall of the corresponding rack body.

[0009] Preferably, the side of the support bearing near the first annular inner groove is also provided with an annular boss, and the inside of the first annular inner groove is also provided with a second annular inner groove adapted to the annular boss. Each of the first annular inner grooves is also provided with a limiting protrusion for restricting the movement of the support bearing in the radial direction. This configuration provides a specific installation method for the support bearing within the load-bearing housing. This structure ensures the coaxiality of the support bearing and the cylinder, thereby guaranteeing that the rack body can slide smoothly along a straight line without deviation. It effectively disperses the radial force transmitted from the rack body onto the robust load-bearing housing, greatly enhancing the structural rigidity and stability of the entire system.

[0010] Preferably, each cylinder is further provided with a rack piston for pushing the rack body to slide radially, and each rack piston and the end of the cylinder away from the bearing housing form an oil cavity.

[0011] Preferably, the side wall of each rack piston is sealed to the inner wall of the cylinder by a silicone sealing ring, and a rack body is provided between the rack pistons inside every two coaxial cylinders. The rack body and the rack piston are designed as separate parts. The design features a rack and pinion piston responsible for dynamic sealing via a sealing ring, focusing on transmitting hydraulic pressure; while the rack body focuses on meshing and transmission with the gears. This separate structure allows the rack body to have slight adaptive adjustment capabilities during installation and operation, automatically compensating for machining and assembly errors.

[0012] Preferably, each cylinder has the same diameter, each cylinder has a cylinder cover at the end away from the bearing housing, each cylinder cover is connected to the bearing housing by a stud, each cylinder cover and the rack piston form an oil chamber, and each cylinder cover is also provided with an oil passage communicating with the inside of the cylinder. The cylinder head is fastened to the bearing housing with studs, forming a robust sealed pressure vessel. The oil passage design allows hydraulic oil to be precisely injected into or discharged from the oil chamber, achieving precise control over the direction of cylinder movement.

[0013] Preferably, the bearing housing is further provided with several supporting bearings, the gear shaft body includes a columnar part and a gear part, the columnar part is connected to the interior of the supporting bearings, and the gear part meshes with the teeth on the rack body; This configuration of the support bearing provides precise, low-friction rotational support for the cylindrical portion of the gear shaft body, enabling it to smoothly output torque.

[0014] 1. The traditional integral rack is divided into two independent parts: the rack body and the rack piston. The ingenious concept of transmission and precision tolerance is achieved through structural separation. This separation design allows the rack body to have a small self-adjustment capability in the cylinder and the rack body to have a small self-adjustment capability in the support bearing. It can automatically compensate for installation errors and automatically compensate for the center distance installation error between the gear shaft body and the rack part. This reduces the installation difficulty and the stringent requirements for machining accuracy, and reduces meshing noise and wear caused by misalignment. 2. The tin bronze support bearing directly bears the radial force generated by the meshing of the rack body and the gear shaft body. Tin bronze has higher compressive strength, load-bearing capacity and self-lubricating properties. The tin bronze support bearing can not only withstand the radial load transmitted from the rack body, but also the excellent self-lubricating and wear-resistant properties of the support bearing greatly reduce the wear between the annular part of the rack body and the support bearing. The service life and reliability of the double gear rack swing cylinder are significantly improved. 3. The inner groove of the bearing bush on the support bearing is filled with grease, which is continuously applied to the annular part during the sliding of the rack body to achieve dynamic lubrication. This not only reduces the coefficient of friction, but also improves lubrication efficiency and reliability, and avoids failure caused by dry friction. The grease storage and application functions are innovatively integrated into the support bearing bush, simplifying maintenance requirements. 4. The rack and pinion piston focuses on sealing and transmitting hydraulic pressure, the rack body focuses on transmitting torque and motion, and the support bearing focuses on resisting radial force. The rational layout of each structure and function, the specialized design, and the overall performance are optimized. Attached Figure Description

[0015] Figure 1 This is a perspective view of the present utility model; Figure 2 This is a cross-sectional view of the present invention; Figure 3 This is a cross-sectional view of some components of this utility model after they have been removed; Figure 4 This is an exploded cross-sectional view of the present invention.

[0016] The markings in the diagram are: 1. Bearing housing; 11. First annular inner groove; 12. Second annular inner groove; 13. Limiting protrusion; 2. Gear shaft body; 21. Columnar part; 22. Gear part; 3. Cylinder barrel; 30. Oil chamber; 4. Rack body; 41. Annular part; 42. Rack part; 5. Support bearing; 51. Bearing inner groove; 52. Annular boss; 6. Rack piston; 7. Cylinder head; 71. Stud; 72. Oil passage; 8. Support bearing. Detailed Implementation

[0017] The present invention will be further described below with reference to the embodiments shown in the accompanying drawings: like Figure 1 and Figure 2 As shown, a cylinder 3 for a gear rack oscillating cylinder includes a bearing housing 1. The bearing housing 1 has a rotatable gear shaft body 2 inside. The bearing housing 1 also has four cylinders 3. The interior of every two coaxial cylinders 3 is connected to the interior of the bearing housing 1. The communication channel between the interior of the two coaxial cylinders 3 and the interior of the bearing housing 1 is used to install a rack body 4 that is pushed and slid by hydraulic oil. If we consider two coaxial cylinders 3 as a group, then two sets of coaxial cylinders 3 are installed on the bearing housing 1; the two sets of cylinders 3 are parallel to each other, and the teeth of the rack bodies 4 inside the two sets of cylinders 3 are all engaged with the gear shaft body 2; the two rack bodies 4 slide in opposite directions inside the corresponding cylinders 3. Under the action of hydraulic pressure in the cylinder 3 in which it is installed, the two racks of the rack body 4 will move in opposite directions at the same time; for example, the first rack body 4 moves downward and the other rack body 4 moves upward, but both rack bodies 4 are meshed with the same gear shaft body 2. The linear movement of the rack body 4 and the gear shaft body 2 forces the gear shaft body 2 to rotate around its axis.

[0018] Each cylinder 3 has the same diameter, and each cylinder 3 has a cylinder cover 7 at the end away from the bearing housing 1. Each cylinder cover 7 is connected to the bearing housing 1 by a stud 71. Each cylinder 3 also has a rack piston 6 inside for pushing the rack body 4 to slide radially. The teeth on the rack body 4 mesh with the teeth on the gear shaft body 2. Each cylinder cover 7 and the rack piston 6 form an oil cavity 30. Each cylinder cover 7 also has an oil passage 72 that communicates with the inside of the cylinder 3. Since there are four cylinders 3, each cylinder 3 has an oil chamber 30. When the first oil chamber 30 is filled with oil, the hydraulic oil can squeeze the rack piston 6, causing the rack piston 6 in the cylinder 3 to slide. Similarly, when the second oil chamber 30 on the same axis is filled with oil, the hydraulic oil in the second oil chamber 30 can squeeze the corresponding rack piston 6, causing the rack piston 6 in the cylinder 3 to slide. At the same time, the first oil chamber 30 is in the oil discharge state. Please refer to Figure 2 When pressurized oil enters from the oil passage 72 of the left top cylinder 3, it acts on the rack piston 6 of the left top cylinder 3: At the same time, the oil in the cylinder 3 at the bottom left side will be discharged from the oil passage 72 in the cylinder 3 and return to the oil tank.

[0019] The rack body 4 located on the left side is pushed by the rack piston 6 inside the top cylinder 3 on the left side, causing it to slide downward relative to the cylinder 3. The rack piston 6 drives the gear shaft body 2 to produce a counterclockwise rotational motion.

[0020] On the other side, pressurized oil enters from the oil passage 72 of the right top cylinder 3 and acts on the rack piston 6 of the right top cylinder 3. At the same time, the oil in the cylinder 3 at the bottom right side will be discharged from the oil passage 72 in the cylinder 3 and return to the oil tank.

[0021] The rack body 4 located on the right side is pushed by the rack piston 6 inside the top cylinder 3 on the right side. The rack body 4 slides upward relative to the cylinder 3, and the rack piston 6 drives the gear shaft body 2 to generate a clockwise rotational motion.

[0022] Because the two rack bodies 4 move simultaneously and in opposite directions, the forces acting on the gear shaft body 2 are balanced. This eliminates the radial load on the gear shaft body 2, resulting in high output torque and smooth operation.

[0023] Please continue to refer to the reference. Figure 4The bearing housing 1 is also provided with two support bearings 8 inside. The gear shaft body 2 includes a columnar part 21 and a gear part 22. The columnar part 21 is connected to the inside of the support bearing 8. The gear part 22 meshes with the teeth on the rack body 4. During the rotation of the gear part 22 of the gear shaft body 2 driven by the rack body 4, the support bearing 8 is used to support and guide the columnar part 21. The columnar part 21 of the gear shaft body 2 passes through the bearing housing 1. The end of the columnar part 21 of the gear shaft body 2 is provided with a keyway, which is directly connected to an external load (such as a robotic arm or turntable). The cylinder 3 itself does not have an extended shaft.

[0024] Please continue to refer to the reference. Figure 3 In this embodiment, the side wall of each rack piston 6 is sealed to the inner wall of the cylinder 3 by a silicone sealing ring, and a rack body 4 is provided between the rack pistons 6 inside every two coaxial cylinders 3. The rack body 4 and the rack piston 6 are designed as separate parts. With this configuration, the rack body 4 and the rack piston 6 are installed together inside the cylinder 3 as independent parts, through dimensional precision control and fit clearance design: The split structure allows the rack body 4 to have a slight adaptive adjustment capability in the inner hole of the cylinder 3, which can automatically compensate for installation errors and ensure that the center distance between the gear shaft body 2 and the rack body 4 always maintains the best meshing state, reducing the installation difficulty and the stringent requirements for machining accuracy.

[0025] Please continue to refer to the reference. Figure 2 and Figure 3 The bearing housing 1 is further provided with a support bearing 5 coaxial with the adjacent cylinder 3. Each support bearing 5 is provided with grease, and the sidewall of the support bearing 5 is in contact with the sidewall of the rack body 4. There is a gap between the sidewall of each rack body 4 and the inner wall of the cylinder 3. The support bearing 5 is made of tin bronze. During the sliding process of the rack body 4 relative to the cylinder 3, during the meshing process of the rack body 4 and the gear part 22 of the gear shaft body 2, the rack body 4 will generate a radial thrust on the side wall of the support bearing 5. Because this solution eliminates the traditional guide belt inside the double rack and pinion swing cylinder, the support bearing 5 is made of high-strength copper alloy material to directly bear the meshing radial force between the rack body 4 and the gear shaft body 2. Specifically, the copper alloy material is tin bronze. This copper alloy material not only has higher compressive strength and load-bearing capacity than the polymer guide belt, but can also effectively cope with larger radial loads. Tin bronze also has excellent self-lubricating properties, which can reduce the frictional resistance between the rack body 4 and the support bearing 5 while improving wear resistance and service life.

[0026] In this embodiment, each rack body 4 includes an annular portion 41 and a rack portion 42. The annular portion 41 of the rack body 4 fits against the side wall of the support bearing 5. The teeth on the rack portion 42 mesh with the teeth on the gear shaft body 2. The support bearing 5 has a bearing inner groove 51 on the side near the annular portion 41. The inside of the bearing inner groove 51 is filled with grease. During the sliding process of the rack body 4 relative to the cylinder 3, the support bearing 5 inside the cylinder 3 mainly supports and guides the rack body 4. In order to further reduce the coefficient of friction, the grease filled in the inner groove 51 of the bearing can always coat the annular part 41 of the rack body 4 during the sliding process. The inner groove 51 of the bearing has the dual function of collecting excess grease and coating grease.

[0027] To further facilitate the installation of the support bearing 5 inside the bearing housing 1, the bearing housing 1 is provided with a plurality of first annular inner grooves 11, the same number as the support bearing 5. One side of each support bearing 5 is coaxially installed inside the first annular inner groove 11, and the other side of each support bearing 5 is attached to the side wall of the corresponding rack body 4. The side of the support bearing 5 near the first annular inner groove 11 is also provided with an annular boss 52. The inside of the first annular inner groove 11 is also provided with a second annular inner groove 12 adapted to the annular boss 52. Each first annular inner groove 11 is also provided with a limiting protrusion 13 for restricting the radial movement of the support bearing 5. During installation, the support bearing 5 and the annular boss 52 are respectively installed in the first annular inner groove 11 and the second annular inner groove 12 inside the bearing housing 1; the rack body 4 is in contact with the side wall of the support bearing 5 during sliding, so the movement tendency of the rack body 4 will be transmitted to the support bearing 5. At this time, the annular boss 52 on the support bearing 5 is canceled by the two annular inner grooves 12, so the support bearing 5 will never move relative to the bearing housing 1.

[0028] By precisely controlling the fitting clearance between the rack body 4 and the inner hole of the support bearing 5, and between the outer diameter of the support bearing 5 and the inner groove of the bearing housing 1, the contradiction between sliding flexibility and support rigidity is perfectly balanced, which not only ensures the smooth movement of the rack body 4, but also effectively suppresses vibration and impact during meshing.

[0029] The rack and pinion piston 6 focuses on sealing and transmitting hydraulic pressure, the rack body 4 focuses on transmitting torque and motion, and the support bearing 5 focuses on resisting radial force. The functional layout of each structure is reasonable, optimizing the overall performance and reliability.

[0030] The working principle and usage method of this utility model.

[0031] Pressurized hydraulic oil enters the oil chamber 30 through the oil passage 72 on the cylinder head 7, pushing the rack piston 6 to move linearly.

[0032] The rack piston 6 pushes the rack body 4, which is separated from it, to slide linearly inside the cylinder 3.

[0033] Please refer to Figure 2 When pressurized oil enters from the oil passage 72 of the left top cylinder 3, it acts on the rack piston 6 of the left top cylinder 3: At the same time, the oil in the cylinder 3 at the bottom left side will be discharged from the oil passage 72 in the cylinder 3 and return to the oil tank.

[0034] The rack body 4 located on the left side is pushed by the rack piston 6 inside the top cylinder 3 on the left side, causing it to slide downward relative to the cylinder 3. The rack piston 6 drives the gear shaft body 2 to produce a counterclockwise rotational motion.

[0035] On the other side, pressurized oil enters from the oil passage 72 of the right top cylinder 3 and acts on the rack piston 6 of the right top cylinder 3. At the same time, the oil in the cylinder 3 at the bottom right side will be discharged from the oil passage 72 in the cylinder 3 and return to the oil tank.

[0036] The rack body 4 located on the right side is pushed by the rack piston 6 inside the top cylinder 3 on the right side. The rack body 4 slides upward relative to the cylinder 3, and the rack piston 6 drives the gear shaft body 2 to generate a clockwise rotational motion.

[0037] Because the two rack bodies 4 move simultaneously and in opposite directions, this symmetrical drive design causes the radial forces acting on the gear shaft body 2 to cancel each other out, thereby eliminating the radial load on the gear shaft body 2. This allows the support bearing 8 to bear almost only pure torque, thus enabling it to output greater torque, operate extremely smoothly, and significantly reduce vibration and noise.

[0038] The rack body 4 and the rack piston 6 are designed as separate rack units. The rack and pinion piston 6 focuses on sealing (through the sealing ring) and transmitting hydraulic pressure, and does not directly participate in meshing.

[0039] The rack body 4 is focused on precise meshing with the gear shaft body 2 and power transmission.

[0040] This design allows the rack body 4 to have slight adaptive adjustment capabilities during installation and operation, automatically compensates for center distance errors, reduces the difficulty of machining and assembly, and ensures the best meshing state.

[0041] Instead of the traditional polymer guide belt, a high-strength, self-lubricating tin bronze support bearing 5 is used to directly bear the radial force generated by the meshing of the rack body 4 and the gear shaft body 2.

[0042] It has higher compressive strength and load-bearing capacity, excellent wear resistance, and long service life. The inner groove 51 of the bearing can store grease, which continuously lubricates the rack body 4 as the annular portion 41 slides, further reducing friction.

[0043] The gear shaft body 2 is precisely supported in the bearing housing 1 by the support bearing 8.

[0044] The support bearing 5 is firmly fixed in the first annular inner groove 11 of the bearing housing 1 through the cooperation of the annular boss 52 and the second annular inner groove 12, as well as the constraint of the limiting protrusion 13, thus ensuring the rigidity and stability of the support.

[0045] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

Claims

1. A sliding bearing for a gear and rack oscillating cylinder, comprising a bearing housing (1), characterized in that, The bearing housing (1) is rotatably provided with a gear shaft body (2). The bearing housing (1) is also provided with several cylinders (3). The interior of every two coaxial cylinders (3) is connected to the interior of the bearing housing (1). The interior of every two coaxial cylinders (3) and the interior of the bearing housing (1) are also provided with a rack body (4) that is pushed and slid by hydraulic oil. The teeth on the rack body (4) mesh with the teeth on the gear shaft body (2). The interior of the bearing housing (1) is also provided with a support bearing (5) that is coaxial with the adjacent cylinders (3). Each support bearing (5) is provided with grease and the side wall of the support bearing (5) is attached to the side wall of the rack body (4). There is a gap between the side wall of each rack body (4) and the inner wall of the cylinder (3).

2. The sliding bearing for a gear and rack oscillating cylinder according to claim 1, characterized in that, Each of the rack bodies (4) includes an annular portion (41) and a rack portion (42). The annular portion (41) of the rack body (4) is attached to the side wall of the support bearing (5). The teeth on the rack portion (42) mesh with the teeth on the gear shaft body (2). The support bearing (5) is made of tin bronze. The support bearing (5) has a bearing inner groove (51) on the side near the annular portion (41). The inside of the bearing inner groove (51) is filled with grease.

3. The sliding bearing for a gear and rack oscillating cylinder according to claim 2, characterized in that, The bearing housing (1) has a number of first annular inner grooves (11) that are the same number as the support bearings (5). One side of each support bearing (5) is coaxially installed inside the first annular inner groove (11), and the other side of each support bearing (5) is attached to the side wall of the corresponding rack body (4).

4. The sliding bearing for a gear and rack oscillating cylinder according to claim 3, characterized in that, The support bearing (5) is provided with an annular boss (52) on the side near the first annular inner groove (11). The first annular inner groove (11) is also provided with a second annular inner groove (12) adapted to the annular boss (52). Each of the first annular inner grooves (11) is also provided with a limiting protrusion (13) for restricting the support bearing (5) from moving in the radial direction.

5. The sliding bearing for a gear and rack oscillating cylinder according to claim 1, characterized in that, Each cylinder (3) is further provided with a rack piston (6) for pushing the rack body (4) to slide radially. Each rack piston (6) and the end of the cylinder (3) away from the bearing housing (1) form an oil cavity (30).

6. The sliding bearing for a gear and rack oscillating cylinder according to claim 5, characterized in that, The side wall of each rack piston (6) is sealed to the inner wall of the cylinder (3) by a silicone sealing ring. A rack body (4) is provided between the rack pistons (6) inside each two coaxial cylinders (3). The rack body (4) and the rack piston (6) are designed as separate units.

7. The sliding bearing for a gear and rack oscillating cylinder according to claim 6, characterized in that, Each cylinder (3) has the same diameter. Each cylinder (3) has a cylinder cover (7) at the end away from the bearing housing (1). Each cylinder cover (7) is connected to the bearing housing (1) by a stud (71). Each cylinder cover (7) and the rack piston (6) form an oil chamber (30). Each cylinder cover (7) is also provided with an oil passage (72) that communicates with the inside of the cylinder (3).

8. The sliding bearing for a gear and rack oscillating cylinder according to any one of claims 1 to 7, characterized in that, The bearing housing (1) is further provided with several supporting bearings (8). The gear shaft body (2) includes a columnar part (21) and a gear part (22). The columnar part (21) is connected to the inside of the supporting bearing (8). The gear part (22) meshes with the teeth on the rack body (4).

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