A rotary hydraulic joint actuator for heavy-duty robots

Abstract

This invention discloses a rotary hydraulic joint actuator for heavy-duty robots. Two input external gears mesh with input internal gears, and the two input external gears are arranged symmetrically at 180°. Two output external gears mesh with output internal gears, and the two output external gears are also arranged symmetrically at 180°. The input and output external gears are coaxially and fixedly connected via gear shafts, which are fixedly mounted on a planetary carrier. Two plunger cylinders are eccentrically connected between the two input external gears and the two output external gears, respectively. The working cycles of the plunger cylinders at the input and output ends of this invention have a certain phase difference, jointly driving the external gears to rotate. This solves the "dead point" problem in transmission and has advantages such as high output torque, smooth drive, and high power-to-weight ratio. It can be used for the motion joints of low-speed, heavy-duty robots.

Description

Technical Field

[0001] This invention pertains to hydraulic joint actuators in the field of hydraulic transmission, and particularly relates to a rotary hydraulic joint actuator for heavy-duty robots. Background Technology

[0002] With the rapid application of robotics technology in engineering, especially in industrial manufacturing, disaster relief, and material transportation, the requirements for the motion load-bearing capacity of robots are constantly increasing. Heavy-duty robots generally operate under harsh conditions and have high load requirements, making their joint drive method crucial. Motor drives have advantages such as being pollution-free, compact in structure, easy to install, and easy to control, but they also have low power density, poor reliability, and limited output torque, making them difficult to use for joint drives in heavy-duty robots.

[0003] Traditional hydraulic systems use pressurized oil as a power source. Compared with electric motor drive, it has a larger output torque and better motion smoothness. Existing hydraulic actuators are usually driven by piston cylinders or hydraulic motors. If they are directly driven to rotate gears, dead point problems will occur, and it will be difficult to achieve smooth drive. Summary of the Invention

[0004] To address the problems existing in the background art, the purpose of this invention is to design a rotary hydraulic joint actuator for heavy-duty robots. This invention combines low-tooth-difference transmission technology and hydraulic drive technology, enabling the device to generate a large output torque while achieving a relatively stable rotary hydraulic drive.

[0005] The technical solution of this invention is as follows:

[0006] It includes a gear mechanism, a hydraulic mechanism, and a planetary carrier. The gear mechanism is fixedly connected to the planetary carrier, and the hydraulic mechanism is located in the middle of the gear mechanism and drives the gear mechanism to operate. The hydraulic mechanism is externally connected to a control system. The gear mechanism and the hydraulic mechanism are respectively equipped with gears and hydraulic cylinders. The control system drives the piston rod of the hydraulic cylinder to move, thereby driving the gear in the gear mechanism to move, thus realizing the stable driving of the equipment to be driven.

[0007] The gear mechanism includes an annular input internal gear, two input external gears, two output external gears, an annular output internal gear, and a gear shaft; the two input external gears are located in the middle of the input internal gears and are arranged symmetrically at 180°; the inner circumference of the input internal gear and the outer circumference of the input external gear are provided with gear rings, and the gear rings of the input external gears mesh with the gear rings of the input internal gears;

[0008] Both external output gears are located in the middle of the internal output gear, and the two external output gears are arranged symmetrically at 180°. Both the inner circumference of the internal output gear and the outer circumference of the external output gear are provided with gear rings, and the gear rings of the external output gear mesh with the gear rings of the internal output gear.

[0009] The input internal gear and the input external gear are coaxially arranged with the output internal gear and the output external gear, respectively. The input external gear and the output external gear are fixedly connected by a gear shaft, which is fixedly mounted on the planetary carrier.

[0010] The hydraulic mechanism includes an input piston cylinder and an output piston cylinder. The input piston cylinder and the output piston cylinder are located in the middle of the input internal gear and the output internal gear, respectively. The two ends of the input piston cylinder are fixedly connected to the outer periphery of the two input external gears, and the two ends of the input piston cylinder are located on both sides of the line connecting the centers of the two input external gears. The two ends of the output piston cylinder are fixedly connected to the outer periphery of the two output external gears, and the two ends of the output piston cylinder are located on both sides of the line connecting the centers of the two output external gears.

[0011] The axis of the input piston cylinder and the axis of the output piston cylinder are not collinear.

[0012] The input internal gear and the input external gear have the same module, and the output external gear and the output internal gear have the same module.

[0013] The input internal gear and the input external gear have the same module, forming a meshing input gear pair. The output internal gear and the input external gear have the same module, forming a meshing output gear pair. The input external gear and the output external gear are fixedly connected to the same gear shaft, forming an external meshing gear set. The gear shaft is mounted on a planet carrier.

[0014] The input and output gear pairs have a small difference in the number of teeth, forming a low-tooth-difference transmission. The input and output external gears are designed as an integrated gear shaft, fixedly connected together. During actual operation, the input internal gear remains stationary. Because the two input gears mesh, the input external gear rotates around the central axis of the planetary carrier while rotating on its own axis. The output external gear is fixedly connected to the input external gear, so their rotation is exactly the same, thus transmitting power to the output internal gear to output speed. The plunger cylinder drives the two input external gears, which are 180° apart at both ends of the planetary carrier, to rotate, increasing the input torque.

[0015] The device uses hydraulic drive instead of electric motor drive, and the oil in the plunger cylinder generates force on the piston rod to drive the pinion at the input end to rotate.

[0016] The plunger cylinder is eccentrically hinged to the external gear at the input end to generate input torque. Each of the input and output ends of the device has a plunger cylinder connected to two external gears at the corresponding ends, and the connection point of the plunger cylinder on the external gear has a certain eccentricity relative to the center of the external gear. When the piston rod of one plunger cylinder passes the center of the external gear at that end, it is driven by the other plunger cylinder to pass through the "dead point".

[0017] Oil can be introduced into both chambers of each plunger cylinder. When the piston rod of the plunger cylinder passes the center of the external gear, that is, when it encounters the "dead point", the oil in the two chambers of the plunger cylinder completes the switching between high pressure and low pressure. That is, the chamber that originally had high pressure oil is switched to low pressure oil, and the chamber that originally had low pressure oil is switched to high pressure oil. This completes the switching of pushing and pulling force on the external gear, enabling it to complete the cycle.

[0018] This invention uses two input-end external gears distributed at 180° as an example. In actual design and manufacturing, the number of input-end external gears can be increased, such as 4×90°, four gears evenly distributed at 90° along the circumference of the planetary carrier, or even more external gears, and so on. This structure results in less impact and better motion smoothness in actual transmission. When the number of input-end external gears increases, the corresponding number of plunger cylinders must also increase.

[0019] The piston rod of this device is hinged to the eccentric position of the input external gear. The pushing and pulling force of the piston rod drives the input external gear to rotate, which in turn drives the output external gear of the planetary carrier to rotate. Finally, the rotational speed of the output internal gear is used as the output. It has the advantages of high output torque, smooth drive, and high power-to-weight ratio, and can be used for the motion joints of low-speed heavy-duty robots.

[0020] The beneficial effects of this invention are as follows:

[0021] 1. This invention uses hydraulic power as a power source, which significantly improves the output torque compared to electric motor drive.

[0022] 2. The present invention uses two pairs of internal meshing gears as the input end and the output end respectively, and the two sets of gears form a structure with a small tooth difference, which improves the reduction ratio and torque transmission ratio.

[0023] 3. The working cycles of the two plunger cylinders at the input and output ends of this invention have a certain phase difference, which jointly drive the external gear to rotate, thus solving the "dead point" problem in the transmission and realizing a relatively stable rotary hydraulic drive.

[0024] 4. The more pairs of external gears involved in the transmission in the device proposed in this invention, the better the transmission smoothness and the greater the power density. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the gear at the input end of the device;

[0026] Figure 2 This is a schematic diagram of the output gear of the device;

[0027] Figure 3 This is a simplified structural diagram of the reducer section in the device;

[0028] Among them: 1. Input end internal gear; 2. Input end external gear; 3. Output end external gear; 4. Output end internal gear; 5. Planetary carrier; 6a, 6b, piston cylinder. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0030] like Figure 1 , Figure 2 and Figure 3 As shown, it includes a gear mechanism, a hydraulic mechanism, and a planetary carrier 5. The gear mechanism is fixedly connected to the planetary carrier 5, and the hydraulic mechanism is located in the middle of the gear mechanism and drives the gear mechanism to operate. The hydraulic mechanism is externally connected to a control system. The gear mechanism and the hydraulic mechanism are respectively equipped with gears and hydraulic cylinders. The control system drives the piston rod of the hydraulic cylinder to move, thereby driving the gear in the gear mechanism to move, thus realizing the stable driving of the equipment to be driven.

[0031] The gear mechanism includes a ring-shaped input internal gear 1, two input external gears 2, two output external gears 3, a ring-shaped output internal gear 4, and a gear shaft. The two input external gears 2 are both located in the middle of the input internal gears 1, and are arranged symmetrically at 180°, meaning the centers of the two input external gears 2 are equidistant from the center of the input internal gears 1, and the centers of the two input external gears 2 lie on the same diameter line. Both the inner circumference of the input internal gear 1 and the outer circumference of the input external gears 2 are provided with... The input external gear 2 meshes with the input internal gear 1; the two output external gears 3 are located in the middle of the output internal gear 4, and the two output external gears 3 are arranged symmetrically at 180°, that is, the centers of the two output external gears 3 are equidistant from the center of the output internal gear 4, and the centers of the two output external gears 3 are on the same diameter line. The inner circumference of the output internal gear 4 and the outer circumference of the output external gear 3 are provided with gear rings, and the gear rings of the output external gear 3 mesh with the gear rings of the output internal gear 4.

[0032] The input internal gear 1 and the input external gear 2 are coaxially arranged with the output internal gear 4 and the output external gear 3, respectively. The input external gear 2 and the output external gear 3 are fixedly connected by a gear shaft, which is fixedly mounted on the planetary carrier 5.

[0033] like Figure 1 and Figure 2As shown, the hydraulic mechanism includes piston cylinder 6a and piston cylinder 6b. Piston cylinder 6a and piston cylinder 6b are located in the middle of the input internal gear 1 and the output internal gear 4, respectively. The two ends of piston cylinder 6a are fixedly connected to the outer periphery of the two input external gears 2, and the two ends of piston cylinder 6a are located on both sides of the line connecting the centers of the two input external gears 2. The two ends of piston cylinder 6b are fixedly connected to the outer periphery of the two output external gears 3, and the two ends of piston cylinder 6b are located on both sides of the line connecting the centers of the two output external gears 3. That is, the line connecting the centers of the two input external gears 2 forms a certain angle with the axis of piston cylinder 6a, and the line connecting the centers of the two output external gears 3 forms a certain angle with the axis of piston cylinder 6b.

[0034] The connection points of the two ends of the plunger cylinder 6a with the input external gear are respectively offset from the center of the input external gear; the connection points of the two ends of the plunger cylinder 6b with the output external gear are respectively offset from the center of the output external gear.

[0035] The axes of plunger cylinder 6a and plunger cylinder 6b are not collinear, that is, plunger cylinder 6a and plunger cylinder 6b form a certain angle.

[0036] The input internal gear 1 and the input external gear 2 have the same module, and the output external gear 3 and the output internal gear 4 have the same module.

[0037] like Figure 1 and Figure 2 As shown, the implementation process of the embodiments of the present invention is as follows:

[0038] First, high-pressure oil and low-pressure oil are respectively introduced into the two chambers of each plunger cylinder 6a and 6b. The high-pressure chamber generates a thrust in the direction of the low-pressure chamber, thereby driving the piston rod to move. The piston rod generates a thrust or pull on the input external gear 2 and the output external gear 3, thereby generating a rotational torque on the input external gear 2 and the output external gear 3. The input internal gear 1 is fixed, and the input external gear 2 always maintains meshing with the input internal gear 1 and rotates under the action of the input torque generated by the plunger cylinder, thus revolving around the axis of the input internal gear 1, thereby driving the planetary carrier 5 to rotate. The output external gear 3 also rotates under the action of the input torque generated by the plunger cylinder. The output external gear 3 rotates at the same speed as the input external gear 2 and always maintains meshing with the output internal gear 4, ultimately driving the output internal gear 4 to output speed and torque.

[0039] When the piston rods of plunger cylinders 6a and 6b pass the center of the input external gear 2 and the output external gear 3, i.e., when they encounter the "dead point", the oil in the two chambers of plunger cylinders 6a and 6b completes the switching between high pressure and low pressure. That is, the chamber that originally had high pressure oil is switched to low pressure oil, and the chamber that originally had low pressure oil is switched to high pressure oil, thus completing the switching of push and pull force. This cycle repeats periodically. When the piston of one of the plunger cylinders is on the same straight line as the center of the external gear at that end, the plunger cylinder at the other end completes the drive, thereby skipping the "dead point".

[0040] The technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made in accordance with the technical solutions of the present invention fall within the protection scope of the present invention.

Claims

1. A heavy-duty robot rotary hydraulic joint execution device, characterized in that: it comprises a gear mechanism, a hydraulic mechanism and a planet carrier (5), the gear mechanism is fixedly connected to the planet carrier (5), the hydraulic mechanism is arranged in the middle of the gear mechanism, and the hydraulic mechanism drives the gear mechanism to operate, and the hydraulic mechanism is connected with a control system; gears and hydraulic cylinders are respectively arranged in the gear mechanism and the hydraulic mechanism, the piston rod of the hydraulic cylinder is driven to move by the control system, so that the gear in the gear mechanism moves, and then the stable driving of the to-be-driven equipment is realized; the gear mechanism comprises an annular input end inner gear (1), two input end outer gears (2), two output end outer gears (3), an annular output end inner gear (4) and a gear shaft; the two input end outer gears (2) are located in the middle of the input end inner gear (1), and the two input end outer gears (2) are symmetrically arranged at 180°, the inner periphery of the input end inner gear (1) and the outer periphery of the input end outer gear (2) are provided with gear rings, and the gear rings of the input end outer gears (2) are engaged with the gear rings of the input end inner gear (1); the two output end outer gears (3) are located in the middle of the output end inner gear (4), and the two output end outer gears (3) are symmetrically arranged at 180°, the inner periphery of the output end inner gear (4) and the outer periphery of the output end outer gear (3) are provided with gear rings, and the gear rings of the output end outer gears (3) are engaged with the gear rings of the output end inner gear (4); the input end inner gear (1) and the input end outer gear (2) are coaxially arranged with the output end inner gear (4) and the output end outer gear (3) respectively, the input end outer gear (2) and the output end outer gear (3) are fixedly connected through the gear shaft, and the gear shaft is fixedly installed on the planet carrier (5); the hydraulic mechanism comprises an input end plunger cylinder (6a) and an output end plunger cylinder (6b), the input end plunger cylinder (6a) and the output end plunger cylinder (6b) are located in the middle of the input end inner gear (1) and the output end inner gear (4) respectively, the two ends of the input end plunger cylinder (6a) are fixedly connected with the outer peripheries of the two input end outer gears (2) respectively, and the two ends of the input end plunger cylinder (6a) are located on the two sides of the center connection line of the two input end outer gears (2) respectively, the two ends of the output end plunger cylinder (6b) are fixedly connected with the outer peripheries of the two output end outer gears (3) respectively, and the two ends of the output end plunger cylinder (6b) are located on the two sides of the center connection line of the two output end outer gears (3) respectively; the axis of the input end plunger cylinder (6a) and the axis of the output end plunger cylinder (6b) are not collinear. the modulus of the input end inner gear (1) and the input end outer gear (2) is the same, and the modulus of the output end outer gear (3) and the output end inner gear (4) is the same.

2. A heavy duty robot rotary hydraulic joint actuator according to claim 1, characterized in that: ​

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