Three-degree-of-freedom parallel mechanism, parallel robot and machine tool

Patent metadata

Field	Value
Publication number	US-12589484-B2
Application number	US-202418760792-A
Country	US
Kind code	B2
Filing date	Jul 1, 2024
Priority date	Dec 15, 2023
Publication date	Mar 31, 2026
Grant date	Mar 31, 2026

Abstract

Disclosed is a three-degree-of-freedom parallel mechanism, a parallel robot and a machine tool. The parallel mechanism includes a fixed frame and a moving platform, and the fixed frame includes a fixed seat and a cylindrical body fixedly connected to the fixed seat; three identical limbs are uniformly distributed in the cylindrical body in a circumferential direction, and each limb includes a prismatic joint A, a hinge A, a swing arm, a hinge B and a hinge C which are sequentially connected; an axis of the hinge A is perpendicular to an axis of movement of the prismatic joint A; an axis of the hinge B is perpendicular to, but does not intersect with the axis of the hinge A, which rotates around the axis of the hinge A; the hinge C has two rotational degrees of freedom.

First claim

What is claimed:

1 . A three degree of freedom (DOF) parallel mechanism, comprising:
a fixed frame and a moving platform, wherein the fixed frame comprises a fixed seat and a cylindrical body fixedly connected to the fixed seat; three identical limbs uniformly distributed in the cylindrical body in a circumferential direction, wherein each limb comprises a prismatic joint, a first hinge, a swing arm, a second hinge, and a third hinge which are sequentially connected; wherein an axis of the first hinge is perpendicular to an axis of movement of the first prismatic joint; an axis of the second hinge is perpendicular to, but does not intersect with the axis of the first hinge, which rotates around the axis of the first hinge; the third hinge has two rotational degrees of freedom; the third hinge comprises a first pivot and a second pivot that intersect at a right angle, wherein the second pivot rotates around an axis of the first pivot, the axis of the first pivot intersects with the axis of the second hinge at a right angle, and the second pivot rotates around the axis of the second hinge; and the second pivot of each limb is rotationally connected with the moving platform.

2 . The three degree of freedom parallel mechanism according to claim 1 , wherein a middle section of the second pivot is a rectangle, and
a shaft hole through which the first pivot penetrates is formed in a center of the second pivot.

3 . The three degree of freedom parallel mechanism according to claim 1 , wherein a longitudinal section of the swing arm is a rectangle with a triangular or arc-shaped notch on one side, and the notch faces towards an axis of the cylindrical body.

4 . The three degree of freedom parallel mechanism according to claim 1 , wherein the prismatic joint comprises:
a connecting plate fixedly connected with the cylindrical body; a linear guide rail fixed on the connecting plate; a saddle in sliding fit on the linear guide rail; and a sliding table fixedly connected to the saddle; wherein a driving device drives the prismatic joint in each limb back and forth along the axis of movement; wherein the driving devices comprise one of the following linear driving structures:
a combined structure of a servo motor and a ball screw pair in which an output shaft of the servo motor is connected with a screw rod of the ball screw pair, and a nut of the ball screw pair is fixedly connected with the sliding table; and
a hydraulic linear driving structure which comprises a hydraulic cylinder, and a piston rod of the hydraulic cylinder is fixedly connected with the sliding table.

5 . The three degree of freedom parallel mechanism according to claim 1 , wherein the second hinge comprises a first hinge mount and a third pivot which are configured to rotate relative to each other, and the third pivot and the first pivot are connected into a cross shaft.

6 . The three degree of freedom parallel mechanism according to claim 5 , wherein a joint part of the third pivot and the first pivot is a cylinder;
an axis of the cylinder coincides with an axis of the third pivot; a height of the cylinder is larger than a diameter of the first pivot; and a diameter of the cylinder is 1.5 to 3 times as large as that of the third pivot.

7 . The three degree of freedom parallel mechanism according to claim 1 , wherein the prismatic joint comprises:
a connecting plate fixedly connected with the cylindrical body; a linear guide rail fixed on the connecting plate; and a saddle in sliding fit on the linear guide rail; wherein the first hinge comprises a second hinge mount and a fourth pivot which rotate relative to each other; wherein one of the second hinge mount and the fourth pivot is fixedly connected with the saddle, and the other of the second hinge mount and the fourth pivot is connected with the swing arm.

8 . The three degree of freedom parallel mechanism according to claim 7 , wherein the second hinge mount of the first hinge and the first hinge mount of the second hinge are integrally connected with the swing arm.

9 . A machine tool, comprising the three degree of freedom parallel mechanism according to claim 1 .

10 . The machine tool of claim 9 , wherein a middle section of the second pivot is a rectangle, and a shaft hole through which the first pivot penetrates is formed in a center of the second pivot.

11 . The machine tool of claim 9 , wherein the second hinge comprises a first hinge mount and a third pivot which are configured to rotate relative to each other, and wherein the third pivot and the first pivot are connected into a cross shaft.

12 . The machine tool of claim 11 , wherein a joint part of the third pivot and the first pivot is a cylinder;
an axis of the cylinder coincides with an axis of the third pivot; a height of the cylinder is larger than a diameter of the first pivot; and a diameter of the cylinder is 1.5 to 3 times as large as that of the third pivot.

13 . A parallel robot, comprising the three degree of freedom parallel mechanism according to claim 1 .

14 . The parallel robot of claim 13 , wherein a middle section of the second pivot is a rectangle, and a shaft hole through which the first pivot penetrates is formed in a center of the second pivot.

15 . The parallel robot of claim 13 , wherein a longitudinal section of the swing arm is a rectangle with a triangular or arc-shaped notch on one side, and the notch faces towards an axis of the cylindrical body.

16 . The parallel robot of claim 13 , wherein the prismatic joint comprises:
a connecting plate fixedly connected with the cylindrical body; a linear guide rail fixed on the connecting plate; a saddle in sliding fit on the linear guide rail; and a sliding table fixedly connected to the saddle; wherein a driving device drives the prismatic joint in each limb back and forth along the axis of movement; the driving devices comprise one of the following linear driving structures:
a combined structure of a servo motor and a ball screw pair in which an output shaft of the servo motor is connected with a screw rod of the ball screw pair, and a nut of the ball screw pair is fixedly connected with the sliding table; and
a hydraulic linear driving structure which comprises a hydraulic cylinder, and a piston rod of the hydraulic cylinder is fixedly connected with the sliding table.

17 . The parallel robot of claim 13 , wherein the second hinge comprises a first hinge mount and a third pivot which are configured to rotate relative to each other, and wherein the third pivot and the first pivot are connected into a cross shaft.

18 . The parallel robot of claim 17 , wherein a joint part of the third pivot and the first pivot is a cylinder;
an axis of the cylinder coincides with an axis of the third pivot; a height of the cylinder is larger than a diameter of the first pivot; and a diameter of the cylinder is 1.5 to 3 times as large as that of the third pivot.

19 . The parallel robot of claim 13 , wherein the prismatic joint comprises:
a connecting plate fixedly connected with the cylindrical body; a linear guide rail fixed on the connecting plate; and a saddle in sliding fit on the linear guide rail; wherein the first hinge comprises a second hinge mount and a fourth pivot which rotate relative to each other; and wherein one of the second hinge mount and the fourth pivot is fixedly connected with the saddle, and the other of the second hinge mount and the fourth pivot is connected with the swing arm.

Assignees

• Univ Tianjin

Inventors

• Liu Haitao
• Shan Xianlei
• Wu Hongye
• Han Jiale
• Xiao Juliang
• Huang Tian

Classifications

• B25J9/144 Primary

  Linear actuators · CPC title

• B25J9/0009

  Constructional details, e.g. manipulator supports, bases · CPC title

• B25J17/0266

  comprising more than two actuating or connecting rods · CPC title

• B25J9/0051

  with kinematics chains of the type rotary-universal-universal or rotary-spherical-spherical, e.g. Delta type manipulators · CPC title

• B25J9/0036 Primary

  with kinematics chains of the type prismatic-rotary-rotary · CPC title