Vehicle step apparatus

Provided is a vehicle step apparatus comprising a first extending and retracting device comprising a first mounting bracket, a first step bracket, and a first arm assembly coupled between the first mounting bracket and the first step bracket and configured to drive the first step bracket to move between an extending position and a retracting position; a second extending and retracting device comprising a second mounting bracket, a second step bracket, and a second arm assembly configured to drive the second step bracket to move; a step mounted on the first step bracket and the second step bracket; a single motor mounted on the first mounting bracket and having a motor shaft coupled with the first arm assembly; and a transmission shaft defining a first end coupled with the motor shaft, and a second end coupled with the second arm assembly via a braking device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and benefits of Chinese Patent Application Serial No. 201510469324.4 and No. 201520580148.7, both filed with the State Intellectual Property Office of P. R. China on Aug. 4, 2015, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention generally relate to the field of vehicle, and more particularly, to a vehicle step apparatus.

2. Description of the Related Art

A vehicle step apparatus mounted on a chassis of a vehicle is used to assist passengers to get on or off the vehicle. The extending and retracting device of the vehicle step apparatus is driven by a motor, and then the step is driven to move between an extending position and a retracting position. In the related art, if the step is driven by two extending and retracting devices, two motors are needed to drive the two extending and retracting devices respectively. The control of the two motors is complex, and the two extending and retracting devices may interfere with each other if the two motors is not synchronous.

In addition, when the step is in the retracting position, the step droops under the gravity of the step and the gravity of the extending and retracting device.

SUMMARY OF THE INVENTION

The present invention seeks to solve at least one of the technical problems existing in the related art. Therefore, embodiments of the present invention provide a vehicle step apparatus. The vehicle step apparatus can prevent the first extending and retracting device and the second extending and retracting device from drooping.

A vehicle step apparatus according to embodiments of the present invention includes: a first extending and retracting device comprising a first mounting bracket, a first step bracket, and a first arm assembly coupled between the first mounting bracket and the first step bracket and configured to drive the first step bracket to move between an extending position and a retracting position; a second extending and retracting device comprising a second mounting bracket, a second step bracket, and a second arm assembly coupled between the second mounting bracket and the second step bracket and configured to drive the second step bracket to move between the extending position and the retracting position; a step mounted on the first step bracket and the second step bracket; a single motor mounted on the first mounting bracket and having a motor shaft coupled with the first arm assembly; and a transmission shaft defining a first end coupled with the motor shaft, and a second end coupled with the second arm assembly via a braking device.

A vehicle step apparatus according to embodiments of the present invention includes: a first extending and retracting device comprising a first mounting bracket, a first step bracket, and a first arm assembly coupled between the first mounting bracket and the first step bracket and configured to drive the first step bracket to move between an extending position and a retracting position; a second extending and retracting device comprising a second mounting bracket, a second step bracket, and a second arm assembly coupled between the second mounting bracket and the second step bracket and configured to drive the second step bracket to move between the extending position and the retracting position; a step mounted on the first step bracket and the second step bracket; a single motor mounted on the first mounting bracket and having a motor shaft coupled with the first arm assembly; and a scroll spring configured to be elastically deformed so as to store energy when the single motor drives the first extending and retracting device to move towards the extending position, and to release energy so as to assist the single motor to drive the first extending and retracting device when the motor drives the first extending and retracting device to move towards the retracting position.

Other objects, features and advantages of the present invention will be readily appreciated as the same becomes better understood after reading the subsequent description taken in connection with the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION

Reference will be made in detail to embodiments of the present invention. Embodiments of the present invention will be shown in drawings, in which the same or similar members and the members having same or similar functions are denoted by like reference numerals throughout the descriptions. The embodiments described herein according to drawings are explanatory and illustrative, not construed to limit the present invention.

The following description provides a plurality of embodiments or examples configured to achieve different structures of the present invention. In order to simplify the publication of the present invention, components and dispositions of the particular embodiment are described in the following, which are only explanatory and not construed to limit the present invention. In addition, the present invention may repeat the reference number and/or letter in different embodiments for the purpose of simplicity and clarity, and the repeat does not indicate the relationship of the plurality of embodiments and/or dispositions. Moreover, in description of the embodiments, the structure of the second characteristic “above” the first characteristic may include an embodiment formed by the first and second characteristic contacted directly, and also may include another embodiment formed between the first and the second characteristic, in which the first characteristic and the second characteristic may not contact directly.

In the description of the present invention, unless specified or limitation otherwise, it should be noted that, terms “mounted,” “coupled” and “coupled” may be understood broadly, such as electronic connection or mechanical connection, inner communication between two members, direct connection or indirect connection via intermediary. These having ordinary skills in the art should understand the specific meanings in the present invention according to specific situations.

A vehicle step apparatus100according to embodiments of the present invention will be described with reference to the drawings.

As shown inFIG. 1toFIG. 10, the vehicle step apparatus100according to embodiments of the present invention comprises a first extending and retracting device10, a second extending and retracting device20, a step80, a single electric motor30and a transmission shaft70.

The first extending and retracting device10comprises a first mounting bracket11, a first step bracket12and a first arm assembly13. The first arm assembly13is coupled between the first mounting bracket11and the first step bracket12, and configured to drive the first step bracket12to move between an extending position and a retracting position. As shown inFIG. 1andFIG. 2, a plurality of lever arms forms the first arm assembly13via pivotal connection, at least one lever arm of the first arm assembly13is coupled with the first mounting bracket11, and at least one lever arm of the first arm assembly13is coupled with the first step bracket12.

The second extending and retracting device20comprises a second mounting bracket21, a second step bracket22and a second arm assembly23. The second arm assembly23is coupled between the second mounting bracket21and the second step bracket22, and configured to drive the second step bracket22to move between the extending position and the retracting position. As shown inFIG. 1andFIG. 2, a plurality of arms forms the second arm assembly23via pivotal connection, at least one arm of the second arm assembly23is coupled with the second mounting bracket21, and at least one arm of the second arm assembly23is coupled with the second step bracket22.

As shown inFIG. 1andFIG. 2, the step80is mounted to the first step bracket12and the second step bracket22, and the single motor30is mounted to the first mounting bracket11. The single motor30has a motor shaft32coupled with the first arm assembly13. The transmission shaft70defines a first end71and a second end72, the first end71is coupled with the motor shaft32, and the second end72is coupled with the second arm assembly23via a braking device1. Specifically, the motor shaft32is coupled with one lever arm of the first arm assembly13, and the transmission shaft70is coupled with one lever arm of the second arm assembly23.

Since the braking device1is coupled between the transmission shaft70and the second extending and retracting device20, a driving force of the single motor30is transmitted to the second extending and retracting device20, and a resistance is transmitted from the second extending and retracting device20to the transmission shaft70. In other words, a force which is resist the gravity of the second extending and retracting device20and an action force of the step80acting on the second extending and retracting device20, is transmitted to the transmission shaft70. Thus, it can prevent the first extending and retracting device10and the second extending and retracting device20from drooping.

In an embodiment, the braking device1comprises a braking bush2, a brake driving shaft3, a brake driven shaft4, a brake shoe5and a first elastic member6.

As shown inFIG. 3toFIG. 5, the brake driving shaft3is coupled with the motor output shaft32of the single motor30, and rotatably disposed in the braking bush2via a first brake bearing7fitted over an outer circumferential surface of the brake driving shaft3. Specifically, the brake driving shaft3defines a first end and a second end. The first end of the brake driving shaft3is coupled with the second end of the transmission shaft70, and the second end of the brake driving shaft3is rotatably disposed in the braking bush2via the first brake bearing7.

An end of the brake driving shaft3(the right end inFIG. 4) has a first axial protrusion3a. As shown inFIG. 4, the brake driving shaft3has a cylindrical shape, and has a first non-circular center hole3b. The first axial protrusion3ais integrally extended outwardly from an end surface of the brake driving shaft3. As shown inFIG. 4, the first axial protrusion3ais formed to have an arc shape which is consistent with the shape of a portion of the side wall of the brake driving shaft3.

In some embodiments, the cross section of the first non-circular center hole3bhas a non-circular shape, such as an elliptical or rectangular shape. An end of the output motor shaft32of the single motor30has a cross section shape adapted to the first non-circular center hole3b, so that the driving force (torque) of the single motor30can be transmitted to the braking bush2.

Specifically, the first non-circular center hole3bis formed in the brake driving shaft3, the second end of the transmission shaft70has a shape adapted to that of the first non-circular center hole3band fitted within the first non-circular center hole3b, and the first end of the transmission shaft70is connected to the motor shaft32via a first connection shaft91.

The brake driven shaft4is coupled with the second extending and retracting device20, and rotatably disposed in the braking bush2via a second brake bearing8fitted over the outer circumferential surface of the brake driven shaft4. The end of the brake driven shaft4opposing to the brake driving shaft3(left end inFIG. 4) has a second axial protrusion4aopposing to the first axial protrusion3a.

Specifically, the brake driven shaft4defines a first end and a second end. The first end of the brake driven shaft4is rotatably disposed in the braking bush2via the second brake bearing8, and has a second axial protrusion4aopposing to the first axial protrusion3a. The second end of the brake driven shaft4is coupled with the second arm assembly23.

As shown inFIG. 4andFIG. 6, the brake driven shaft4has a cylindrical shape, and has a second non-circular center hole4b. The second axial protrusion4ais integrally extended outwardly from an end surface of the brake driven shaft4. As shown inFIG. 4andFIG. 6, the second axial protrusion4ais formed to have an arc shape which is consistent with the shape of a portion of the side wall of the brake driven shaft4.

The cross section of the second non-circular center hole4bhas a non-circular shape, such as an elliptical or rectangular shape. The second extending and retracting device20has a cross section shape adapted to the second non-circular center hole4b, so that the driving force (torque) of the brake driven shaft4can be transmitted to the second extending and retracting device20.

Specifically, the second non-circular center hole4bis formed in the brake driven shaft4, the second arm assembly23is connected to the brake driven shaft4via a second connection shaft92, the first end of the second connection shaft92has a shape adapted to that of the second non-circular center hole4band fitted within the second non-circular center hole4b.

As shown inFIG. 5andFIG. 6, the brake shoe5is disposed between the first axial protrusion3aand the second axial protrusion4a, i.e. the brake shoe5is sandwiched between the first axial protrusion3aand the second axial protrusion4a. In addition, the thickness at both ends of the brake shoe5in the lengthwise direction decreases gradually, in which the lengthwise direction of the brake shoe5is consistent with the radial direction of the braking bush2when the brake shoe5is disposed in the braking bush2. Namely, both end surfaces of the brake shoe5in the lengthwise direction are bevels, and transited to the top surface (the upper surface inFIG. 6) through arcs respectively. Certainly, a person ordinarily skilled in the art can understand that the maximum length L of the brake shoe5in the lengthwise direction should be slightly smaller than the inner diameter D of the braking bush2, so that the brake shoe5can rotate in the braking bush2when a maximum length part of the brake shoe5which is longest passes through the center of the braking bush2.

The first elastic member6defines a first end6aand a second end6b. The first end6aof the first elastic member6is coupled with a surface of the second axial protrusion4aopposing to the first axial protrusion3a(namely inside surface), and the second end6bof the first elastic member6is coupled with the brake shoe5and normally urging the brake shoe5towards the first axial protrusion3a.

In an embodiment, the first elastic member6comprises a compression spring.

Operations of the vehicle step apparatus100according to an embodiment of the present invention will be described below.

When the step80is needed to be moved from the retracting position to the extending position, the single motor30rotates clockwise as shown inFIG. 6, and the single motor30drives the first extending and retracting device10to extend out. At the same time, the driving force (torque) of the single motor30is transmitted to the transmission shaft70and the brake driving shaft3, and the brake driving shaft3rotates in the braking bush2while the first axial protrusion3aof the brake driving shaft3urges the brake shoe5toward the second axial protrusion4aof the brake driven shaft4against the elastic force of the first elastic member6. After the brake shoe5moves toward the second axial protrusion4a, the maximum length portion of the brake shoe5passes through the center of the braking bush2. Since the maximum length L of the brake shoe5is slightly smaller than the inner diameter of the braking bush2, the brake shoe5can rotate in the braking bush2so that the first axial protrusion3acan transmit the driving force to the second axial protrusion4avia the brake shoe5. The second axial protrusion4atransmits the driving force to the second extending and retracting device20so as to drive the second extending and retracting device20to extend out, and then the step80is moved from the retracting position to the extending position.

When the step80is needed to be moved from the extending position to the retracting position, the single motor30rotates counterclockwise as shown inFIG. 6, and the single motor30drives the first extending and retracting device10to retract. At the same time, the driving force (torque) of the single motor30is transmitted to the transmission shaft70, the brake driving shaft3(the first axial protrusion3a), the brake shoe5, the brake driven shaft4(the second axial protrusion4a) and the second extending and retracting device20, so that the first extending and retracting device10and the second extending and retracting device20are retracted, and then the step80is moved to the retracting position.

When the step80is in the retracting position, the single motor30stops rotating, both the gravity of the step80and the gravity of the second extending and retracting device20make the first extending and retracting device10and second extending and retracting device20droop, i.e. make the first extending and retracting device10and second extending and retracting device20move towards the extending position. A torque generated by the gravity of the step80and the gravity of the second extending and retracting device20acts on the second extending and retracting device20.

Since the first extending and retracting device10is coupled with the single motor30and locked by the single motor30, the first extending and retracting device10does not droop. Since the second extending and retracting device20is coupled with the braking device1, the torque mentioned above is transmitted to the brake driven shaft4. At the time, the second axial protrusion4acompresses the first elastic member6towards the brake shoe5and the first axial protrusion3a, and the brake shoe5moves towards the first axial protrusion3aunder elastic force of the first elastic member6. At the same time, the second axial protrusion4arotates and urges the brake shoe5towards the first axial protrusion3a, so that the maximum length portion of the brake shoe5is offset from the center of the braking bush2.

As shown inFIG. 6, both ends of the brake shoe5in the lengthwise direction contacts the inner wall of the braking bush2, so that the brake shoe5cannot be rotated in the braking bush2because of the friction therebetween. The second axial protrusion4a(thus brake driven shaft4) cannot be further rotated, thus the torque of the second axial protrusion4acannot be transmitted to the first axial protrusion3avia the brake shoe5, so that the first axial protrusion3acannot be rotated, further the transmission shaft70cannot be rotated. Thus, the second extending and retracting device20is braked so as to prevent the second extending and retracting device20from drooping.

Advantageously, the first extending and retracting device10is configured as one of a four-link mechanism10a, a five-link mechanism10band a six-link mechanism10c, and the second extending and retracting device20is configured as one of a four-link mechanism10a, a five-link mechanism10band a six-link mechanism10c.

The structure of the first extending and retracting device10will be described as an example below. A person ordinarily skilled in the art can understand that the second extending and retracting device20is the same as the first extending and retracting device10.

In an embodiment shown inFIG. 7, the first extending and retracting device10is a four-link mechanism10a, and the first extending and retracting device10comprises the first mounting bracket11, the first step bracket12and the first arm assembly13. The first arm assembly13is coupled between the first mounting bracket11and the first step bracket12.

The first arm assembly13comprises a first lever arm131and a second lever arm132. An upper end of the first arm131is pivotally coupled with the first mounting bracket11via a first connection pin136, and a lower end of the first arm131is pivotally coupled with the first step bracket12via a second connection pin137. An upper end of the second arm132is pivotally coupled with the first mounting bracket11via a third connection pin138, and a lower end of the second arm132is pivotally coupled with the first step bracket12via a fourth connection pin139.

In an embodiment shown inFIG. 8, the first extending and retracting device10is a five-link mechanism10b, and the first extending and retracting device10comprises the first mounting bracket11, the first step bracket12and the first arm assembly13. The first arm assembly13is coupled between the first mounting bracket11and the first step bracket12. The first arm assembly13comprises a first lever arm131, a third lever arm133and a fourth lever arm134.

An upper end of the first arm131is pivotally coupled with the first mounting bracket11via a first connection pin136, and a lower end of the first arm131is pivotally coupled with the first step bracket12via a second connection pin137. An upper end of the third arm133is pivotally coupled with the first mounting bracket11via a third connection pin138, and a lower end of the third arm133is pivotally coupled with an upper end of the fourth arm134via a fifth connection pin140. A lower end of the fourth arm134is pivotally coupled with the first step bracket12via a fourth connection pin139.

In an embodiment shown inFIG. 9, the first extending and retracting device10is a six-link mechanism10c, and the first extending and retracting device10comprises the first mounting bracket11, the first step bracket12and the first arm assembly13. The first arm assembly13is coupled between the first mounting bracket11and the first step bracket12. The first arm assembly13comprises a first lever arm131, a third lever arm133, a fourth lever arm134and a fifth lever arm135.

An upper end of the first arm131is pivotally coupled with the first mounting bracket11via a first connection pin136, and a lower end of the first arm131is pivotally coupled with the first step bracket12via a second connection pin137. An upper end of the third arm133is pivotally coupled with the first mounting bracket11via a third connection pin138, and a lower end of the third arm133and an upper end of the fourth arm134are pivotally coupled with a first end of the fifth arm135via a fifth connection pin140. The second end of the fifth arm135is pivotally coupled with a middle portion of the first arm131by a sixth connection pin141. A lower end of the fourth arm134is pivotally coupled with the first step bracket12via a fourth connection pin139.

In the embodiments of the above-mentioned first extending and retracting device10, the motor shaft32of the single motor30is coupled with the first arm131or the second arm132via the first connection shaft91so as to drive it to rotate, and then the driving force of the single motor30is finally transmitted to the first step bracket12so as to drive the first step bracket12to extend and retract.

As shown inFIG. 1, the motor shaft32is coupled with the second end of the transmission shaft70by the first connection shaft91, and the second arm assembly23is coupled with the braking device1by the second connection shaft92.

Specifically, the first connection shaft91defines a first end and a second end. The first end of the first connection shaft91is coupled with the motor shaft32, and the second end of the first connection shaft91is coupled with the transmission shaft70. The first connection shaft91, the motor shaft32and the transmission shaft70are coaxially disposed. Moreover, the first connection shaft91is coupled with an arm of the first arm assembly13.

The second connection shaft92defines a first end and a second end. The first end of the second connection shaft92is coupled with the braking device1, and the second end of the second connection shaft92is coupled with an arm of the second arm assembly23. Thus, the driving force of the single motor30is transmitted to the first extending and retracting device10via the first connection shaft91and transmitted to the second extending and retracting device20via the first connection shaft91, the transmission shaft70and the second connection shaft92, so that transmission loss is decreased and the structure of the vehicle step apparatus100is more compactly, and then both a movement of the first extending and retracting device10and a movement of the second extending and retracting device20happen more synchronously.

In some embodiments, the vehicle step apparatus100further comprises a second elastic member40. The second elastic member40is configured to elastically deform so as to store energy when the single motor30drives the first extending and retracting device10and the second extending and retracting device20to move towards the extending position, and to release energy so as to assist the single motor30to drive the first extending and retracting device10and the second extending and retracting device20when the single motor30drives the first extending and retracting device10and the second extending and retracting device20to move towards the retracting position.

Specifically, when the motor shaft32rotates clockwise as shown inFIG. 6, the motor shaft32drives the second elastic member40to move and makes the second elastic member40be deformed so as to store energy, and the step80is moved from the retracting position to the extending position.

When the motor shaft32rotates counterclockwise as shown inFIG. 6, the second elastic member40releases energy so as to assist the single motor30to drive the first extending and retracting device10to retract. Thus, both the load and the work current of the single motor30are decreased, so that the work current of the single motor30in the process of driving the step80to extend approximately equals the work current of the single motor30in the process of driving the step80to retract so as to effectively protect the single motor30and prolong work-life of the single motor30.

More specifically, the first mounting bracket11is fixed on a vehicle, at least one arm of the first arm assembly13is pivotally coupled with the first mounting bracket11, and at least one arm of the first arm assembly13is pivotally coupled with the first step bracket12. The motor shaft32is coupled with an arm of the first arm assembly13so as to drive the first arm assembly13to move, and then to drive the first step bracket12coupled with the first arm assembly13to move. Thus, the single motor30rotates clockwise to drive the first extending and retracting device10to extend and rotates counterclockwise to drive the first extending and retracting device10to retract. Since the structure of the second extending and retracting device20is the same as the structure of the first extending and retracting device10, the course of motion of the second extending and retracting device20is not described.

Further, the second elastic member40comprises a scroll spring40a. The scroll spring40adefines a first end41and a second end42. The first end41of the scroll spring40ais fixed, and the second end42of the scroll spring40ais driven by the motor shaft32so as to twist.

Specifically, as shown inFIG. 1andFIG. 10, an end of the outer turn of the scroll spring40ais bent outwards so as to form the first end41, an end of the inner turn of the scroll spring40ais bent inwards so as to form the second end42. Thus, the first end41comprises the end of the outer turn and a portion of the outer turn which is coupled with the end of the outer turn, the second end42comprises the end of the inner turn and a portion of the inner turn which is coupled with the end of the inner turn.

When the first extending and retracting device10and the second extending and retracting device20is extended, i.e. when the step80is extended, the first end41of the scroll spring40ais fixed, and the second end42of the scroll spring40arotates along with the motor shaft32and is twisted by the motor shaft32so as to store energy.

When the first extending and retracting device10and the second extending and retracting device20is retracted, i.e. when the step80is retracted, the first end41of the scroll spring40ais fixed, and the second end42of the scroll spring40arotates along with the motor shaft32and releases energy so as to assist to drive the first extending and retracting device10and the second extending and retracting device20to retract. In addition, the structure of the scroll spring40ais simple and compact, and the scroll spring40ais easily to be mounted.

Additionally, the elastic member may be elastic sheet, belleville spring or other member which can elastically deform easily.

A suitable scroll spring40acan be chosen based on the differential between the load of the single motor30in the process of driving the step80to extend and the load of the single motor30in the process of driving the step80to retract, so that the load of the single motor30in the process of driving the step80to extend and the load of the single motor30in the process of driving the step80to retract can be balanced.

In an embodiment, as shown inFIG. 10, the vehicle step apparatus100further comprises a first cover61and a first connection plate51. A first recess is formed in a casing31of the single motor30, and the first cover61first covers the first recess to define a cavity. The first connection plate51is mounted in the cavity and driven by the motor shaft32to rotate. The scroll spring40ais mounted within the cavity, the first end41of the scroll spring40ais fixed to the first cover61, and the second end42of the scroll spring40ais coupled with the first connection plate51.

Specifically, the first connecting plate51is substantially a circular plate. The first connecting plate51is disposed in the cavity, and the first connecting plate51defines a first surface opposing to the first recess and a second surface opposing to the first cover61. The first connecting plate51is directly or indirectly coupled with the motor shaft32and is driven by the motor shaft32to rotate. The scroll spring40ais fitted over the first connecting plate51, and the second end42of the scroll spring40ais coupled with the first connecting plate51and rotates along with the first connecting plate51.

Thus, the scroll spring40acan be integrated in the single motor30so as to decrease transmission loss and make the structure of the vehicle step apparatus100more compactly.

In some embodiments, the first cover61is detachably fastened to the casing31. A limitation notch61ais formed in the first cover61, a limitation column111is formed on the first mounting bracket11, and the limitation column111is fitted within the limitation notch61ato mount the first cover61to the first mounting bracket11. The first end41of the scroll spring40ais fitted over the limitation column111.

As shown inFIG. 10, the first recess is formed in a side of the casing31facing the first mounting bracket11. The first cover61comprises a cover body and a flange coupled with an edge of the cover body. A stepped positioning surface is formed on an inner wall of the flange, and the first cover61covers the first recess via the stepped positioning surface. The limitation notch61aextends from an edge of the first cover61to an inner of the first cover61.

The limitation column111is formed on a side of the first mounting bracket11opposing to the single motor30, and a catch groove fitted with the limitation notch61ais formed in the limitation column111. The first cover61bears against the casing31via lower surfaces of the catch groove of two limitation columns111so as to limit the first cover61in the axial direction. Side surfaces of the catch grooves of two limitation columns111limit the first cover61in both the radial direction and the circumferential direction. The second end42of the scroll spring40apasses through the limitation notch61aand is fitted over the limitation column111.

Thus, the first cover61, the casing31and the first mounting bracket11are fixedly coupled together, and a suitable position is provided to mount the second end42of the scroll spring40a, so that a twisted deformation of the scroll spring40ais decreased during mounting and using.

The first cover61, the first connecting plate51and the first recess may be a circular shape, an elliptical and so on. The number of the limitation notch61ais more than two, and a plurality of the limitation notch61ais provided and evenly spaced apart from each other along a circumferential direction of the first cover61. The number of the limitation column111is more than two.

Advantageously, a first catch groove51ais formed in an outer circumferential surface of the first connection plate51, and the second end42of the scroll spring40ais inserted into and fitted within the first catch groove51a. The first connection shaft91is coupled with the motor shaft32via splined connection and coupled with the transmission shaft70via a bolt15. The first connection plate51is fitted over the first connection shaft91and coupled with the first connection shaft91via splined connection.

Specifically, as shown inFIG. 10, the first catch groove51aextends from an edge of the first connecting plate51to an inner of the first connecting plate51, and the first catch groove51aextends along the radial direction of the first connecting plate51. A center of the first connecting plate51has a first spline hole, and the motor shaft32has a second spline hole. The first connection shaft91has an external spline, and the first connection shaft91is coupled with the motor shaft32and the first connecting plate51via spline connection so as to ensure driving force transmission and make installation and disassembly to be easy.

The first connection shaft91is coupled with an arm of the first arm assembly13and passes through the first mounting bracket11. Thus, the single motor30drives the first connection shaft91and the first connecting plate51to rotate, and the second end42of the scroll spring40afixed on the first connecting plate51is rotated along with the first connecting plate51, so that the scroll spring40ais twisted tensely.

In an embodiment, a mounting hole311is formed in the casing31, and the limitation column111is passed through the mounting hole311. A threaded hole111ais formed in the limitation column111, and the single motor30is mounted on the first mounting bracket11via a bolt15fitted within the threaded hole111a.

Specifically, the limitation column111passes through the limitation notch61aand bears against the casing31. The mounting hole311of the casing31is in one-to-one relationship with the threaded hole111aof the limitation column111, and the bolt15passes through the mounting hole311and is fitted within the threaded hole111aso as to mount the casing31to the first mounting bracket11. Thus, the single motor30, the first connecting plate51and the first mounting bracket11are mounted together via the bolt15, and it is easy to change and maintain the scroll spring40a.

In addition, the casing31, the first connecting plate51and the first mounting bracket11are mounted together via welding or other suitable manner.

In an embodiment shown inFIG. 1, the second elastic member40comprises one scroll spring40a, and the one scroll spring40ais mount on an outside of the second mounting bracket21away from the first mounting bracket11. The one scroll spring40adefines a first end41and a second end42, and the first end41is fixed and the second end42is driven by the second connection shaft92to twist. Thus, the scroll spring40aprovides driving force for the second extending and retracting device20so as to prevent a transmission from the motor shaft32to the second connection shaft92from delaying, so that both a movement of the first extending and retracting device10and a movement of the second extending and retracting device20happen more synchronously.

In some embodiments, a second recess112is formed in the outside of the second mounting bracket21away from the first mounting bracket11, and the second recess112is covered by a second cover62. The first end of the second connection shaft92is coupled with the braking device1, and the second end of the second connection shaft92is extended beyond the outside of the second mounting bracket21. A second connection plate52is fitted over and coupled with the second end of the second connection shaft92via splined connection, and a second catch groove52bis formed in an outer circumferential surface of the second connection plate52.

A catch column113is formed on the outside of the second mounting bracket21, and the catch column113is disposed in the second recess112. The one scroll spring40ais disposed in the second recess112, the first end41of the one scroll spring40ais fitted over the catch column113, and the second end42of the one scroll spring40ais inserted into the second catch groove52b.

Thus, the motor shaft32drives the first connection shaft91, the transmission shaft70, the second connection shaft92and the second connection plate52to rotate in same direction.

In some embodiments, the second elastic member40comprises a first scroll spring and a second scroll spring. The first scroll spring is disposed between the single motor and the first mounting bracket11, and the second scroll spring is disposed on an outside of the second mounting bracket21away from the first mounting bracket11.

A person ordinarily skilled in the art can understand that the numbers of the first extending and retracting device10, the second extending and retracting device20and the scroll spring40aare more than two. In addition, the first end41of the scroll spring40ais directly coupled with the motor shaft32, and the second end42of the scroll spring40ais coupled with at least one of the casing31, the second mounting bracket21and the first cover61.

In other embodiments shown inFIG. 11andFIG. 12, the vehicle step apparatus100comprises a first extending and retracting device10, a second extending and retracting device20, a step80, a single motor30and a scroll spring40a.

The first extending and retracting device10comprises a first mounting bracket11, a first step bracket12and a first arm assembly13. The first arm assembly13is coupled between the first mounting bracket11and the first step bracket12, and configured to drive the first step bracket12to move between an extending position and a retracting position.

The second extending and retracting device20comprises a second mounting bracket21, a second step bracket22and a second arm assembly23. The second arm assembly23is coupled between the second mounting bracket21and the second step bracket22, and configured to drive the second step bracket22to move between the extending position and the retracting position.

The step80is mounted on the first step bracket12and the second step bracket22, and the single motor30is mounted on the first mounting bracket11. The single motor30has a motor shaft32coupled with the first arm assembly13.

The scroll spring40ais configured to elastically deform so as to store energy when the single motor30drives the first extending and retracting device10to move towards the extending position, and to release energy so as to assist the single motor30to drive the first extending and retracting device10when the single motor30drives the first extending and retracting device10to move towards the retracting position.

Specifically, when the step80is needed to be moved from the retracting position to the extending position, the single motor30rotates clockwise as shown inFIG. 6, and the single motor30drives the first extending and retracting device10to extend out, so that the first step bracket12drives the step80to be moved from the retracting position to the extending position. At the same time, the step80drives the second extending and retracting device20to extend out.

When the step80is needed to be moved from the extending position to the retracting position, the single motor30rotates anticlockwise as shown inFIG. 6, and the single motor30drives the first extending and retracting device10to retract, so that the first step bracket12drives the step80to be moved from the extending position to the retracting position. At the same time, the step80drives the second extending and retracting device20to retract.

In an embodiment, as shown inFIG. 11andFIG. 12, the vehicle step apparatus100further comprises a first cover61and a first connection plate51. A first recess is formed in a casing31of the single motor30, and the first cover61first covers the first recess to define a cavity. The first connection plate51is mounted in the cavity and driven by the motor shaft32to rotate. The scroll spring40ais mounted within the cavity, the first end41of the scroll spring40ais fixed in the first cover61, and the second end42of the scroll spring40ais coupled with the first connection plate51.

Specifically, the first connecting plate51is a circular plate. The first connecting plate51is disposed in the cavity, and the first connecting plate51defines a first surface opposing to the first recess and a second surface opposing to the first cover61. The first connecting plate51is directly or indirectly coupled with the motor shaft32and is driven by the motor shaft32to rotate. The scroll spring40ais fitted over the first connecting plate51, and the second end42of the scroll spring40ais coupled with the first connecting plate51and rotates along with the first connecting plate51.

In some embodiments, the first cover61is detachably fastened to the casing31. A limitation notch61ais formed in the first cover61, a limitation column111is formed on the first mounting bracket11, and the limitation column111is fitted within the limitation notch61ato mount the first cover61on the first mounting bracket11. The first end41of the scroll spring40ais fitted over the limitation column111.

A first catch groove51ais formed in an outer circumferential surface of the first connection plate51, and the second end42of the scroll spring40ais inserted into and fitted within the first catch groove51a. The first connection shaft91is coupled with the motor shaft32via splined connection and coupled with the transmission shaft70via a bolt, and the first connection plate51is fitted over the first connection shaft91and coupled with the first connection shaft91via splined connection.

As shown inFIG. 11andFIG. 12, a mounting hole311is formed in the casing31, and the limitation column111is passed through the mounting hole311. A threaded hole111ais formed in the limitation column111, and the single motor30is mounted on the first mounting bracket11via a bolt15fitted within the threaded hole111a.

One scroll spring40ais provided, and the one scroll spring40ais mounted on an outside of the second mounting bracket21away from the first mounting bracket11. The one scroll spring40adefines a fixed first end41and a second end42driven by the second connection shaft92to twist.

A second recess112is formed in the outside of the second mounting bracket21and covered by a second cover61. The first end of the second connection shaft92is connected to the braking device1, and the second end of the second connection shaft92is extended beyond the outside of the second mounting bracket21.

A second connection plate52is fitted over and coupled with the second end of the second transmission shaft70via splined connection, and a second catch groove52bis formed in an outer circumferential surface of the second connection plate52. A catch column113formed on the outside of the second mounting bracket21is disposed in the second recess112. The one scroll spring40ais disposed in the second recess112, the first end41of the one scroll spring40ais fitted over the catch column113, and the second end42of the one scroll spring40ais inserted into the second catch groove52b.

The scroll spring40acomprises a first scroll spring and a second scroll spring. The first scroll spring is disposed between the single motor30and the first mounting bracket11, and the second scroll spring is disposed on an outside of the second mounting bracket21.

Although explanatory embodiments have been shown and described, it would be appreciated by those skilled in the art that the above embodiments cannot be construed to limit the present invention, and changes, alternatives, and modifications can be made in the embodiments without departing from spirit, principles and scope of the present invention.