A three-degree-of-freedom hydraulic joint

Abstract

This invention provides a three-degree-of-freedom hydraulic joint, belonging to the field of hydraulic drive and servo control. The invention features an inner rotor oscillating blade surrounded by an intermediate oscillating blade. The inner rotor oscillating blade and the intermediate oscillating blade's internal cavity form two cavities, realizing the first degree of freedom of the inner rotor's rotation around its output shaft. The intermediate oscillating blade is nested within the outer rotor cavity, dividing the outer rotor cavity into two cavities, realizing the second degree of freedom of rotational oscillation of the intermediate oscillating blade. The intermediate oscillating blade, inner rotor, and outer rotor are nested and installed within a stator base, forming two cavities with the hollow portion of the stator base, enabling the outer rotor to drive the assembly to achieve the third degree of freedom of rotation. This invention can realize three independent degrees of freedom of movement in a mechanical joint, significantly reducing the total mass of the robotic arm and simplifying the traditional complex robotic arm transmission chain. Hydraulic drive can obtain greater driving force compared to electric drive, combining simplicity and efficiency.

Description

Technical Field

[0001] This invention relates to a three-degree-of-freedom hydraulic joint, belonging to the field of hydraulic drive and servo control. Background Technology

[0002] With the development of industrial technology, the application of robots is becoming increasingly widespread, and the complexity of robotic arms is also increasing. Currently, most robotic arms achieve one degree of rotational freedom through a single actuator, which determines the current complexity of robotic arm structures. Three-degree-of-freedom joints can significantly reduce the number of joints in a robot, greatly simplifying the mechanical structure and significantly improving its mechanical rigidity.

[0003] Currently, each joint of a hydraulically driven robotic arm is driven by a single motor. Since motors account for a large proportion of the weight of the robotic arm joints, multiple motors account for a significant portion of the weight of the cantilever section of the robotic arm, and the structure is also relatively complex. Therefore, under the above circumstances, using a novel three-degree-of-freedom motor to enable a single motor to control the movement of three joints can significantly reduce the weight of the cantilever section of the robotic arm. This is a method to obtain a more compact structure and high power density, which can effectively improve the load capacity and driving accuracy of the robotic arm. Summary of the Invention

[0004] The purpose of this invention is to solve the problems existing in the prior art, and to provide a three-degree-of-freedom swing hydraulic joint that has an outer rotor, an intermediate swing blade and an inner rotor nested together and directly driven by hydraulics, and can realize three independent degrees of freedom of rotation.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A three-degree-of-freedom hydraulic joint, the three-degree-of-freedom hydraulic joint mainly includes a stator base, a stator cover, an outer rotor, an intermediate swing blade, and an inner rotor;

[0007] The stator base has two pairs of stator base oil holes. The stator cover fits with the stator base plane and the fit is sealed. A hollow cavity is formed between the stator cover and the stator base. The stator cover has a spherical auxiliary to the swing and rotation of the output shaft of the inner rotor.

[0008] The inner rotor has a sphere in the middle, with one end being the output shaft of the inner rotor, which is also the output shaft of the three-degree-of-freedom hydraulic joint, and the other end being the inner rotor blade. The inner rotor blade is nested with the intermediate body swing blade, and the motion is guided by the support bearing. The cross-sectional shape of the intermediate body swing blade is rectangular, with the upper and lower curved surfaces being the inner and outer spherical surfaces. The inner spherical surface of the intermediate body swing blade forms a mating surface with the outer spherical surface of the inner rotor's middle sphere, and the outer spherical surface of the intermediate body swing blade forms a mating surface with the inner spherical surface of the outer rotor. A stator is provided in the inner cavity of the intermediate body swing blade, thereby dividing the inner cavity of the intermediate body swing blade into the first pair of working cavities, which allows the inner rotor to rotate around its own axis.

[0009] The nested assembly of the inner rotor blades and the intermediate body oscillating blades is placed in the hollow cavity of the outer rotor. The bottom of the hollow cavity of the outer rotor is an inner spherical surface. The outer spherical surface of the intermediate body oscillating blades and the inner spherical surface of the outer rotor form a mating surface. The nested assembly of the inner rotor blades and the intermediate body oscillating blades divides the hollow cavity of the outer rotor into a second pair of working cavities, which allows the nested assembly of the inner rotor blades and the intermediate body oscillating blades to oscillate in the parallel plane of the inner cavity of the outer rotor.

[0010] The outer rotor body is a hollow body with inner and outer spherical surfaces. The center of the inner and outer spherical surfaces coincides with the center of the inner rotor. The outer rotor has two parallel fan-shaped sides. Sliding bearings are placed on the parallel sides. At the same time, oil distribution grooves are provided on the parallel fan-shaped sides. Oil holes of the outer rotor are provided on the oil distribution grooves. A pair of oil holes on the stator base can be connected to the oil holes of the outer rotor through the oil distribution grooves to distribute oil for the drive of the intermediate body swing blades.

[0011] The inner rotor blades, intermediate body oscillating blades and outer rotor are nested together to form an assembly placed in the hollow cavity of the stator base. The outer spherical surface of the outer rotor and the inner spherical surface of the stator base cooperate to form a mating surface. The assembly of the outer rotor divides the hollow cavity of the stator base into a third pair of working cavities, allowing the outer rotor assembly to oscillate in the parallel plane of the inner cavity of the stator base.

[0012] The present invention discloses a three-degree-of-freedom hydraulic joint, wherein the sliding bearings are respectively engaged with the inner rotor, the outer rotor, the stator base and the stator cover, serving as auxiliary support when the outer rotor swings; the support bearings are respectively engaged with the inner rotor and the intermediate body swing blades, supporting the intermediate body swing blades when the inner rotor swings, ensuring that the inner rotor and the intermediate body swing blades only have relative rotational motion.

[0013] The present invention provides a three-degree-of-freedom hydraulic joint, wherein the cross-sectional shape of the intermediate body swing blade is rectangular to ensure that the intermediate body swing blade cannot spin within the inner cavity of the outer rotor, and the two parallel planes on the side of the outer rotor ensure that the outer rotor cannot spin within the stator base.

[0014] The present invention provides a three-degree-of-freedom hydraulic joint, wherein the first pair of working cavities, the second pair of working cavities, and the third pair of working cavities are independent of each other.

[0015] The present invention provides a three-degree-of-freedom hydraulic joint in which the driving oil of the inner rotor blades is introduced through the output shaft, passes through the intermediate ball, and reaches both sides of the inner rotor blades.

[0016] This invention discloses a three-degree-of-freedom hydraulic joint, capable of achieving three independent degrees of freedom of motion. It effectively simplifies the structure of robotic arms or joints requiring multiple degrees of freedom, and significantly simplifies the transmission chains of traditional, complex robotic arms or joints. Compared to motor-driven joints, the hydraulically driven three-degree-of-freedom hydraulic joint can achieve a greater driving torque, thus significantly improving the system's power density. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the three-degree-of-freedom hydraulic joint of the present invention;

[0018] Figure 2 This is the invention Figure 1 Sectional view along AA;

[0019] Figure 3 This is the invention Figure 1 Sectional view along BB;

[0020] Figure 4 This is a schematic diagram of the inner rotor and intermediate body oscillating blade structure of the present invention;

[0021] Figure 5 This is a schematic diagram of the external rotor structure of the present invention;

[0022] Figure 6 This is an exploded view of the inner rotor, middle layer oscillating blades, and outer rotor of the present invention;

[0023] In the diagram: 1-Stator base; 2-Intermediate body oscillating blade; 3-Outer rotor; 4-Sealing ring; 5-Sliding bearing; 6-Stator top cover; 7-Screw; 8-Inner rotor; 9-Support bearing; 1-1, 1-2, 1-3, 1-4-Stator base oil holes; 3-1, 3-2-Oil distribution grooves; 3-3, 3-4-Outer rotor oil holes; 8-1-Output shaft; 8-2-Inner rotor blade; 8-3, 8-4-Inner rotor oil holes; C, D-Inner rotor working cavity; E, F-Intermediate body oscillating blade working cavity; G, H-Outer rotor working cavity. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to the accompanying drawings: This embodiment is implemented under the premise of the technical solution of the present invention, and detailed implementation methods are given, but the protection scope of the present invention is not limited to the following embodiments.

[0025] Example 1: As Figure 1-6As shown, the three-degree-of-freedom hydraulic joint involved in this embodiment includes a stator base, a stator cover, an inner rotor, an intermediate swing blade, an outer rotor, a support bearing, a sliding bearing, an oil distribution mechanism, and a sealing assembly.

[0026] The inner rotor is integrated with the output shaft of the three-degree-of-freedom hydraulic joint. The inner rotor sphere is connected to the output shaft, enabling the output shaft to rotate in three degrees of freedom. The other end of the inner rotor is the inner rotor blade. The inner rotor blade is nested with the intermediate swing blade, and the motion is guided by the support bearing. The cross-sectional shape of the intermediate swing blade is rectangular, and the upper and lower curved surfaces are the inner and outer spherical surfaces. The inner spherical surface of the intermediate swing blade and the outer spherical surface of the inner rotor's intermediate sphere form a mating surface, and the outer spherical surface of the intermediate swing blade and the inner spherical surface of the outer rotor form a mating surface. The intermediate swing blade has a stator inside its inner cavity, which divides the inner cavity of the intermediate swing blade into the first pair of working cavities. When oil enters one cavity and oil exits the other cavity, the inner rotor can rotate around its own axis, that is, the output shaft rotates around the axis, realizing the first degree of freedom rotation.

[0027] The nested assembly of the inner rotor blades and the intermediate body oscillating blades is placed in the hollow cavity of the outer rotor. The bottom of the hollow cavity of the outer rotor is an inner spherical surface. The outer spherical surface of the intermediate body oscillating blades and the inner spherical surface of the outer rotor form a mating surface. The nested assembly of the inner rotor blades and the intermediate body oscillating blades divides the hollow cavity of the outer rotor into a second pair of working cavities. When oil enters one cavity and oil exits the other cavity, the nested assembly of the inner rotor blades and the intermediate body oscillating blades can oscillate in the parallel plane of the inner cavity of the outer rotor, thereby causing the output to oscillate and realizing the second degree of freedom of rotation.

[0028] The outer rotor body is a hollow body with inner and outer spherical surfaces. The center of the inner and outer spherical surfaces coincides with the center of the inner rotor. The outer rotor has two parallel fan-shaped sides. Sliding bearings are placed on the parallel sides. At the same time, the parallel fan-shaped sides are provided with oil distribution grooves. The oil distribution grooves are provided with oil holes of the outer rotor. A pair of oil holes on the stator base can be connected to the oil holes of the outer rotor through the oil distribution grooves to distribute oil for the drive of the intermediate body swing blades.

[0029] The inner rotor blades, intermediate swing blades, and outer rotor are nested together to form an assembly placed in the hollow cavity of the stator base. The outer spherical surface of the outer rotor and the inner spherical surface of the stator base cooperate to form a mating surface. The assembly of the outer rotor divides the hollow cavity of the stator base into a third pair of working cavities. When oil enters one cavity and oil exits from the other cavity, the outer rotor assembly can swing in the parallel plane of the cavity inside the stator base. The output shaft also swings in the same direction along with the inner rotor, realizing the third degree of freedom of rotation.

[0030] The intermediate body oscillating blade has a rectangular cross-section to ensure that it cannot spin within the outer rotor cavity; the two parallel sides of the outer rotor ensure that the outer rotor can only move along the direction parallel to the stator base without spinning.

[0031] The output shaft has a pair of oil holes to provide oil for the rotation of the inner rotor blades; the stator base has two pairs of oil passages, one pair to provide oil for the oscillation of the intermediate body blades, and the other pair to provide oil for the rotation of the outer rotor.

[0032] Example 2: Figure 1-6 As shown, the three-degree-of-freedom hydraulic joint involved in this embodiment mainly includes a stator base 1, a stator cover 6, an inner rotor 8, an intermediate swing blade 2, an outer rotor 3, a support bearing 9, a sealing ring 4, and a sliding bearing 5.

[0033] Inner rotor 8 Figure 6 As shown, one end is the output shaft 8-1, the middle is a sphere, and the other end is the inner rotor blade 8-2. The inner rotor blade 8-2 is nested with the intermediate body swing blade 2, and the support bearing 9 is placed between them. The inner rotor blade 8-2 and the intermediate body swing blade 2 form two working cavities C and D. The rotation of the extended shaft 8-1 around the axis is controlled by the rotation of the inner rotor blade 8-2 within the inner cavity of the intermediate body swing blade 2, thus realizing the rotation of degree of freedom a.

[0034] The intermediate oscillating blade 2 and the inner rotor blade 8-2 are combined and placed inside the inner cavity of the outer rotor 3, dividing the inner cavity of the outer rotor 3 into two working cavities E and F. The intermediate oscillating blade 2 assembly oscillates within the inner cavity of the outer rotor 3, driving the oscillation of the protruding shaft 8-1. The intermediate oscillating blade 2 oscillates along a pair of parallel planes within the inner cavity of the outer rotor, achieving a rotational degree of freedom b.

[0035] The stator base 1 and stator cover 6 are sealed together by a sealing ring 4, forming a spherical cavity in the middle. The combination of the inner rotor blade 8-2, the intermediate swing blade 2, and the outer rotor 3 is placed inside this spherical cavity. The outer spherical surface of the outer rotor 3 mates with the inner spherical surface of the stator base 1, dividing the spherical cavity into two working cavities G and H. The swing of the output shaft 8-1 is controlled by controlling the swing of the outer rotor 3, with the center being the center of the inner rotor 8-1, thus achieving rotation of the degree of freedom c, which is perpendicular to the degree of freedom b. The three degrees of freedom a, b, and c are independent of each other.

[0036] The driving oil for the rotation of the inner rotor is achieved through oil distribution within the output shaft. The oil enters the inner rotor oil holes 8-3 and 8-4 through the oil holes on the output shaft, and then enters the working cavities C and D on both sides of the inner rotor blades 8-2, thus achieving oil distribution within the shaft of the inner rotor.

[0037] Example 3: Figure 1-6As shown, the working process of a three-degree-of-freedom hydraulic joint involved in this embodiment is as follows:

[0038] The inner rotor 8 has an output shaft 8-1 at one end, a sphere in the middle, and an inner rotor blade 8-2 at the other end. The inner rotor 8 rotates around the center of the sphere. The inner rotor blade 8-2 is nested with the intermediate body oscillating blade 2. A support bearing 9 is placed between the outer spherical surface of the inner rotor 8 and the inner spherical surface of the intermediate body oscillating blade 2. The inner rotor blade 8-2 and the intermediate body oscillating blade 2 form two working cavities C and D, as shown in the figure. Figure 3 As shown. When pressurized oil flows into the working chamber C through the inner rotor oil hole 8-3 on the output shaft, the oil applies pressure to the inner rotor blades 8-2, causing the inner rotor blades 8-2 to swing towards the working chamber D. The oil in the working chamber D is discharged from the output shaft through the inner rotor oil hole 8-4. Reverse swing means that the oil flows in the opposite direction. Since the inner rotor blades 8-2 and the output shaft 8-1 are fixed together through the intermediate sphere of the inner rotor, the output shaft 8-1 also rotates accordingly, i.e., degree of freedom a;

[0039] The intermediate oscillating blade 2 and the inner rotor blade 8-2 are assembled and placed inside the inner cavity of the outer rotor 3, dividing the inner cavity of the outer rotor 3 into two working cavities E and F, as shown below. Figure 1 As shown. When pressurized oil flows into the outer rotor oil distribution groove 3-1 through the stator base oil hole 1-1, the oil distribution groove 3-1 ensures that the stator base oil hole 1-1 and the outer rotor oil hole 3-3 are connected when the outer rotor 3 rotates in the stator base 1. The oil enters the sealed cavity F through the outer rotor oil hole 3-3. The pressurized oil applies pressure to the intermediate body swing blade 2, causing the intermediate body swing blade 2 to swing towards the sealed cavity E. Under the action of the support bearing 9, the intermediate body swing blade 2 drives the inner rotor blade 8-2 to swing, so the output shaft 8-1 of the inner rotor 8 also swings accordingly. At the same time, the oil in the working cavity E flows into the oil distribution groove 3-2 through the outer rotor oil hole 3-4, and then flows out through the stator base oil hole 1-2. The reverse swing, that is, the oil flows in the opposite direction, realizes the control of rotation along the parallel plane of the inner cavity of the outer rotor 3, that is, degree of freedom b;

[0040] The inner rotor blade 8-2, intermediate oscillating blade 2, and outer rotor 3 are assembled within the cavity of the stator base 1 and stator cover 6. The outer rotor 3 can rotate along the inner spherical surface of the stator base 1, with the center of rotation being the center of the inner rotor 8. The working cavities G and H formed by the outer rotor 3 and the stator base 1 are as follows: Figure 2As shown. When pressurized oil flows into the working cavity H through the stator base oil holes 1-3, it applies hydraulic pressure to the side of the outer rotor, pushing the outer rotor to rotate along the inner spherical surface of the stator base 1. Due to the nesting relationship between the inner rotor 8, the intermediate swing blade 2, and the outer rotor 3, the rotation of the outer rotor 3 is equivalent to the rotation of the inner rotor 8. The extension shaft 8-1 of the inner rotor 8 rotates with the rotation of the inner rotor 8, with the center of rotation being the center of the inner rotor 8 sphere. As the volume of the sealed cavity H increases, the volume of the sealed cavity G decreases accordingly. The oil flows out through the stator base oil holes 1-4. Reverse rotation, i.e., the oil flows in the opposite direction, realizes rotation perpendicular to the direction of freedom b, i.e., degree of freedom c.

[0041] By rotating the inner rotor blades relative to the intermediate swing blades, rotating the inner rotor blades and the intermediate swing blade assembly relative to the outer rotor, and rotating the inner rotor blades, the intermediate swing blades, and the outer rotor assembly relative to the stator base, the rotation of the three degrees of freedom of the three-degree-of-freedom hydraulic joint is realized, and the three degrees of freedom are independent of each other.

[0042] The above description is merely a preferred embodiment of the present invention. These specific embodiments are different implementations based on the overall concept of the present invention, and the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A three-degree-of-freedom hydraulic joint, characterized in that, The three-degree-of-freedom hydraulic joint mainly includes a stator base (1), a stator cover (6), an outer rotor (3), an intermediate swing blade (2), a support bearing (9), and an inner rotor (8). The inner rotor (8) has a sphere in the middle, one end of which is the inner rotor output shaft (8-1), which is also the output shaft of the three-degree-of-freedom hydraulic joint, and the other end is the inner rotor blade (8-2); a pair of inner rotor oil holes (8-3, 8-4) are provided between the output shaft (8-1), the sphere in the middle of the inner rotor (8) and the inner rotor blade (8-2). The cross-section of the intermediate swing blade (2) is rectangular, with an inner spherical surface and an outer spherical surface at the top and bottom. The inner spherical surface and the outer spherical surface are respectively matched with the intermediate sphere of the inner rotor (8) and the inner spherical surface of the outer rotor (3). The inner rotor blade (8-2) is nested with the intermediate swing blade (2) and is supported by the support bearing (9). The inner spherical surface of the intermediate swing blade (2) and the outer spherical surface of the intermediate sphere of the inner rotor (8) form a mating surface. The inner rotor blade (8-2) divides the intermediate swing blade (2) into the first pair of working cavities C and D. When oil enters one cavity and oil exits the other cavity, the inner rotor (8) rotates around its own axis, that is, the output shaft (8-1) rotates around the axis, realizing the first degree of freedom of rotation. The outer rotor (3) is a hollow body with inner and outer spherical surfaces. The nested assembly of the inner rotor blades (8-2) and the intermediate body oscillating blades (2) is placed inside the hollow cavity of the outer rotor (3). The outer spherical surface of the intermediate body oscillating blades (2) and the inner spherical surface of the outer rotor (3) form a mating surface. The nested assembly divides the hollow cavity of the outer rotor (3) into a second pair of working cavities E and F. When oil enters one cavity and oil exits the other cavity, the nested assembly of the inner rotor blades (8-2) and the intermediate body oscillating blades (2) is in... The outer rotor (3) swings in the parallel plane of the inner cavity, causing the output shaft (8-1) to swing along with it, thus realizing the second degree of freedom of rotation; the center of the inner and outer spherical surfaces of the outer rotor (3) coincides with the center of the inner rotor (8). The outer rotor (3) has two parallel fan-shaped sides. A sliding bearing (5) is placed at the center of the parallel fan-shaped sides. A pair of oil distribution grooves (3-1, 3-2) are provided on the parallel fan-shaped sides. Corresponding outer rotor oil holes (3-3, 3-4) are provided on the pair of oil distribution grooves (3-1, 3-2). The stator base (1) has two pairs of stator base oil holes (1-1, 1-2, 1-3, 1-4). The stator cover (6) is in planar fit with the stator base (1), and a sealing ring (4) is provided at the fit. A hollow cavity is formed between the stator cover (6) and the stator base (1). The stator cover (6) has the swing and rotation of the output shaft (8-1) of the spherical auxiliary inner rotor (8). The inner rotor blades (8-2), the intermediate swing blades (2) and the outer rotor (3) are nested together to form an assembly placed in the hollow cavity of the stator base (1). The outer spherical surface of the outer rotor (3) and the inner spherical surface of the stator base (1) form a mating surface, dividing the hollow cavity of the stator base (1) into a third pair of working cavities G and H. When oil enters one cavity and oil is discharged from the other cavity, the outer rotor assembly swings along the parallel plane of the hollow cavity of the stator base (1), and the output shaft (8-1) also swings along this swing direction with the inner rotor (8), realizing the third degree of freedom of rotation. The inner rotor (8) has a pair of oil passages, which provide oil for the rotation of the inner rotor blades (8-2) through a pair of inner rotor oil holes (8-3, 8-4); the stator base (1) has two pairs of oil passages, one pair of which provides oil for the oscillation of the intermediate body oscillating blades (2) through a pair of stator base oil holes (1-1, 1-2), a pair of oil distribution grooves (3-1, 3-2), a pair of outer rotor oil holes (3-3, 3-4), and the cooperation of the second pair of working cavities E, F; the other pair provides oil for the rotation of the outer rotor (3) through the cooperation of another pair of stator base oil holes (1-3, 1-4) and the third pair of working cavities G, H.

2. The three-degree-of-freedom hydraulic joint according to claim 1, characterized in that, The intermediate body oscillating blade (2) has a rectangular cross-section to ensure that the intermediate body oscillating blade (2) cannot spin in the cavity of the outer rotor (3). The two parallel planes on the side of the outer rotor (3) ensure that the outer rotor (3) cannot spin in the stator base (1). These two constraints on the spin motion ensure that the output shaft (8-1) of the three-degree-of-freedom hydraulic joint can generate three independent degrees of freedom motion.

3. The three-degree-of-freedom hydraulic joint according to claim 1, characterized in that, The sliding bearing (5) has four surfaces: a spherical surface, a cylindrical surface, and two planes, which respectively cooperate with the inner rotor (8), the outer rotor (3), the stator base (1), and the stator cover (6).

4. The three-degree-of-freedom hydraulic joint according to claim 1, characterized in that, The first pair of working cavities, the second pair of working cavities, and the third pair of working cavities are independent of each other.

5. The three-degree-of-freedom hydraulic joint according to claim 1, characterized in that, A support bearing (9) is provided between the spherical surface of the inner rotor (8) and the intermediate body swing blade (2) to support the intermediate body swing blade (2) and ensure that the intermediate body swing blade (2) always has only a relative rotational motion relationship with the inner rotor (8) during the swinging process.

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