Robot

1 . A wheel module comprising:

a first hinge and a second hinge mounted to a bottom of a robot;

an in-wheel motor including:

a drive wheel; and

a motor configured to rotate the drive wheel;

a first link arm connected to the motor and rotatably coupled to the first hinge by a first hinge shaft;

a first caster connected to the first link arm;

a second link arm rotatably connected to the first link arm by a second hinge shaft, and coupled to the second hinge by a guide pin; and

a second caster connected to the second link arm,

wherein the second hinge includes a pin guide configured to guide displacement of the guide pin.

2 . The wheel module of claim 1 , wherein the first link arm includes:

a first caster mount located at a front portion of the first link arm, the first caster mount being configured to rotatably support the first caster;

a first hinge shaft penetrating portion located in a central portion of the first link arm, the first hinge shaft penetrating portion being configured to rotatably support the first hinge shaft; and

a second hinge shaft penetrating portion located at a rear portion of the first link arm, the second hinge shaft penetrating portion being configured to rotatably support the second hinge shaft.

3 . The wheel module of claim 2 , wherein the first hinge includes:

a first mounter configured to be mounted to the bottom of the robot; and

a pair of side brackets extending from the first mounter, the pair of side brackets being spaced apart in a left and right direction, and

wherein the first hinge shaft passes through the pair of side brackets and the first hinge shaft penetrating portion.

4 . The wheel module of claim 1 , wherein a height of the second hinge shaft is higher than a height of the first hinge shaft.

5 . The wheel module of claim 1 , wherein the first link arm includes:

an upper arm surrounding an upper portion of a support shaft of the motor; and

a lower arm surrounding a lower portion of the support shaft of the motor, the lower arm being fastened to the upper arm.

6 . The wheel module of claim 1 , wherein one of the first link arm or the second link arm has a protrusion protruding toward another of the first link arm or the second link arm, and

wherein the another of the first link arm or the second link arm has a stop surface configured to come into contact with the protrusion or to move apart from the protrusion.

7 . The wheel module of claim 6 , wherein the protrusion is arranged to move away from the stop surface when a height of the first caster is higher than a height of the second caster, and

wherein the protrusion is arranged to approach the stop surface when the height of the first caster is lower than the height of the second caster.

8 . The wheel module of claim 1 , wherein the pin guide is a guide hole extending in a front and rear direction of the second hinge.

9 . The wheel module of claim 8 , wherein the guide pin is movable into contact with a rear end of the guide hole when the second hinge shaft is lowered, and

wherein the guide pin is movable into contact with a front end of the guide hole when the second hinge shaft is raised.

10 . The wheel module of claim 1 , wherein the second link arm includes:

a second hinge shaft penetrating portion located at a front portion of the second link arm, the second hinge shaft penetrating portion being configured to rotatably support the second hinge shaft;

a guide pin mount located at a central portion of the second link arm; and

a second caster mount located at a rear portion of the second link arm, the second caster mount being configured to rotatably support the second caster.

11 . The wheel module of claim 10 , wherein the second hinge further includes:

a second mounter configured to be mounted to the bottom of the robot; and

a pair of side brackets protruding from the second mounter, the pair of side brackets being spaced apart in a left and right direction, and

wherein the guide pin passes through the pair of side brackets and the guide pin mount.

12 . A robot comprising:

a robot frame including a bottom plate; and

at least one wheel module mounted to the bottom plate,

wherein the at least one wheel module includes:

a first hinge and a second hinge mounted to the bottom plate;

an in-wheel motor including:

a drive wheel; and

a motor configured to rotate the drive wheel;

a first link arm extending from the motor and rotatably connect to the first hinge by a first hinge shaft;

a first caster connected to the first link arm;

a second link arm rotatably connected to the first link arm by a second hinge shaft, and coupled to the second hinge by a guide pin; and

a second caster connected to the second link arm,

wherein the second hinge includes a pin guide configured to guide displacement of the guide pin.

13 . The robot of claim 12 , wherein the at least one wheel module includes:

a left wheel module mounted to the bottom plate; and

a right wheel module mounted to the bottom plate to be spaced apart from the left wheel module.

14 . The robot of claim 12 , wherein the first link arm extends from the motor in a forward direction of the robot, and

wherein the second link arm extends from the first link arm in a rearward direction of the robot.

15 . The robot of claim 14 , wherein the first link arm includes:

a first caster mount located at a front portion of the first link arm, the first caster mount being configured to rotatably support the first caster;

a first hinge shaft penetrating portion located in a central portion of the first link arm, the first hinge shaft penetrating portion being configured to rotatably support the first hinge shaft; and

a second hinge shaft penetrating portion located at a rear portion of the first link arm, the second hinge shaft penetrating portion being configured to rotatably support the second hinge shaft.

16 . The robot of claim 12 , wherein the second link arm includes:

a second hinge shaft penetrating portion located at a front portion of the second link arm, the second hinge shaft penetrating portion being configured to rotatably support the second hinge shaft;

a guide pin mount located at a central portion of the second link arm; and

a second caster mount located at a rear portion of the second link arm, the second caster mount being configured to rotatably support the second caster.

17 . The robot of claim 12 , wherein a height of the second hinge shaft is higher than a height of the first hinge shaft.

18 . The robot of claim 12 , wherein one of the first link arm or the second link arm has a protrusion protruding toward another of the first link arm or the second link arm, and

wherein the another of the first link arm or the second link arm has a stop surface configured to come into contact with the protrusion or to move apart from the protrusion.

19 . The robot of claim 12 , wherein the pin guide is a guide hole extending in a front and rear direction of the second hinge.

20 . A wheel module comprising:

an in-wheel motor including:

a drive wheel; and

a motor configured to rotate the drive wheel;

a first link arm connected to the motor;

a first hinge rotatably connected to the first link arm by a first hinge shaft;

a first caster connected to the first link arm;

a second link arm connected to the first link arm by a second hinge shaft, the second link arm including a guide pin;

a second hinge connected to the second link arm, the second hinge including a pin guide configured to guide displacement of the guide pin; and

a second caster connected to the second link arm,

wherein the second link arm includes:

a second hinge shaft penetrating portion located at a front portion of the second link arm;

a guide pin mount located at a central portion of the second link arm; and

a second caster mount located at a rear portion of the second link arm.