Actuator for an electric side step device

Abstract

The present invention includes: a driving motor; a first worm shaft that transmits a driving force of the driving motor by deceleration; a first worm that engages with the first worm shaft; a second worm shaft that connects with the first worm; a second worm that engages with the second worm shaft; and a main shaft that connects with the second worm. The second worm shaft includes: a screw portion; a lower end shaft portion that is formed below the screw portion, and is engaged with an inner ring of a lower bearing; a spacer portion that is formed between the screw portion and the lower end shaft portion, and presses the inner ring of the lower bearing downward; an upper end shaft portion that is formed above the screw portion, and is engaged with the first worm. The diameter of the spacer portion of the second worm shaft is larger than the diameter of the lower end shaft portion and smaller than the inner diameter of an outer ring of the lower bearing. According to the present invention, the inner ring of the lower bearing is not moved by the spacer portion of the second worm shaft, and working noise caused by the movement of the inner ring of the lower bearing is not generated, thereby improving the functional stability.

Description

Technical Field

[0001] This invention relates to an actuator for starting an electric side step device in a vehicle with a high vehicle body to help passengers get on and off the vehicle conveniently. Background Technology

[0002] SUVs and other vehicles with high body height are equipped with side steps to facilitate passengers getting in and out of the vehicle.

[0003] like Figure 1 The side pedal device includes: a pedal (foot pedal) (omitted in the attached figure), chain-connected to the vehicle body; and an actuator 5 for activating the pedal. The actuator 5 includes: a drive motor 10 for generating power; a first worm gear shaft 12 for transmitting power by reducing the rotational force of the drive motor; a first worm gear 14 meshing with the first worm gear shaft 12; a second worm gear shaft 15 engaging with the first worm gear 14 and rotating together with the first worm gear 14; and a second worm gear 17 meshing with the second worm gear shaft 15, and the second worm gear 17 being connected to the main shaft 19.

[0004] The drive motor 10 is a gear motor, which includes: a motor part having a fixed element, a rotor and a rotating shaft connected to the rotor; and a reduction part having a plurality of reduction gears assembled on the rotating shaft and an output shaft connected thereto.

[0005] The working characteristic of gear motors is that the output shaft speed is greatly reduced relative to the rotating shaft, which leads to a relatively stronger rotational torque. In mechanical industrial fields that require this low-rotation, high-torque working characteristic, it has been a commonly used machine device for a long time.

[0006] The first worm gear 14 is made of synthetic resin material and is formed by molding the second worm gear shaft 15, which is made of metal material.

[0007] According to the prior art, the operation of the drive motor 10 is transmitted to the main shaft 19 through the worm shafts 12 and 15 and the worm wheels 14 and 17, and the rotation of the main shaft 19 causes the pedal (omitted in the figure) to work.

[0008] The second worm gear shaft 15 includes a screw portion 151, an upper shaft portion 152 above the screw portion 151, and a lower shaft portion 153 below the screw portion 151. The upper shaft portion 152 is supported by an upper bearing 20. A thread cap 30 is provided above the upper bearing 20, which serves as a finishing element by engaging with the outer cover H thread.

[0009] The upper bearing 20 and the lower bearing 22 include inner wheels 201 and 221 and outer wheels 202 and 222, as well as bearing balls 203 and 223 disposed between them. The inner wheel 201 of the upper bearing 20 is connected to the upper end shaft portion 152 of the second worm gear shaft 15, and the inner wheel 221 of the lower bearing 22 is connected to the lower end shaft portion 153 of the second worm gear shaft 15. Each outer wheel 202 and 222 is fixed to the outer cover H.

[0010] On the other hand, in the process of manufacturing electric side pedal devices, it is preferable to minimize assembly tolerances by precision manufacturing all components, but in reality, assembly tolerances will occur, which will lead to a decrease in the operation rate of the assembly process.

[0011] Therefore, since the front end of the screw portion 151 of the second worm gear shaft 15 and the lower bearing 22 do not contact each other due to the consideration of component assembly tolerances in the past, the installation of the second worm gear shaft 15 can be carried out more easily.

[0012] However, in this prior art, according to the worm gear coupling structure of the second worm gear 14 and the second worm gear shaft 15, if the second worm gear shaft 15 rotates, a relative resistance is generated on the screw portion 151 of the second worm gear shaft 15 along the normal direction. Part of this resistance will act as an axial force that causes the second worm gear shaft 15 to move along the length direction.

[0013] On the other hand, the upper bearing 20 and lower bearing 22 used in the prior art are ordinary radial bearing types. This structure makes the bearing balls 203 and 223 simply set between the inner wheels 201 and 221 and the outer wheels 202 and 222, without considering axial force, that is, without considering the resistance structure against axial force.

[0014] Therefore, according to the prior art, the outer wheels 202 and 222 of bearings 20 and 22 are respectively firmly fixed to the outer cover H, while the inner wheels 201 and 221, which rotate together with the upper shaft portion 152 and the lower shaft portion 153 of the second worm gear shaft 15, move slightly along the axial direction due to the axial force of the second worm gear shaft 15, thereby generating working noise. Summary of the Invention

[0015] Technical issues

[0016] As described above, the present invention addresses the problems of the prior art as described above. The object of the present invention is to provide an actuator for an electric side pedal device that includes a second worm gear shaft that prevents the inner wheels of the upper and lower bearings from moving due to the axial force generated during rotation.

[0017] Technical solution

[0018] The second worm gear shaft used in the actuator of the electric side pedal device of the present invention for achieving the aforementioned purpose includes: a screw portion; an upper shaft portion formed above the screw portion and fastened to the inner wheel of the upper bearing; a spacer portion formed below the screw portion for pressing the inner wheel of the lower bearing; and a lower shaft portion formed below the spacer portion and fastened to the inner wheel of the lower bearing.

[0019] The diameter of the spacer portion of the second worm gear shaft is larger than the diameter of the lower shaft portion and smaller than the inner diameter of the outer wheel of the lower bearing.

[0020] The manufacturing method of the second worm gear shaft includes: a cutting step, in which a continuous steel bar is cut to a specified length to manufacture a base bar; an upper shaft forming step, in which the upper front end of the cut base bar is machined within a specified range to form an upper shaft for fastening into an inner gear of an upper bearing; a lower shaft forming step, in which the lower front end of the base bar is machined within a specified range to form a lower shaft; a spacer forming step, in which a specified range connected to the lower shaft of the base bar is machined to form a spacer; and a screw forming step, in which the range between the upper shaft and the spacer of the base bar is machined to form a screw.

[0021] The effects of the invention

[0022] The actuator of the electric side pedal device of the present invention has the following advantages: structurally, the spacer portion of the second worm gear shaft prevents the inner wheels of the upper and lower bearings from moving, thus avoiding the working noise caused by the movement of the inner wheels of each bearing and improving functional stability. Attached Figure Description

[0023] Figure 1 A diagram illustrating the structure of the actuator of a prior art electric side pedal device.

[0024] Figure 2 A diagram illustrating the cross-sectional structure of the first and second worm gear shafts in the prior art.

[0025] Figure 3 A diagram illustrating the bearing support structure of a prior art second worm gear shaft.

[0026] Figure 4 A diagram illustrating the clearance state of the upper and lower bearings supporting the second worm gear shaft in the prior art.

[0027] Figure 5 A diagram illustrating the second worm gear shaft of the present invention.

[0028] Figure 6 A diagram illustrating the pressing state of the bearing formed by the second worm gear shaft according to the present invention.

[0029] Figure 7 A diagram illustrating the manufacturing process of the second worm gear shaft of the present invention.

[0030] Figure 8 A diagram illustrating the structure of the actuator of an electric side pedal device according to another embodiment of the present invention. Detailed Implementation

[0031] The following is with reference to the appendix. Figures 5 to 8 The specific details for implementing this invention are described in detail.

[0032] Structures identical to those in the prior art are given the same reference numerals and their descriptions are omitted.

[0033] like Figure 5 and Figure 6 As shown, the second worm gear shaft 16 of the actuator for the electric side pedal device of the present invention includes: a screw portion 161; an upper shaft portion 162 formed above the screw portion 161 and fastened to the inner wheel 201 of the upper bearing 20; a spacer portion 163 formed below the screw portion 161 for pressing the inner wheel 221 of the lower bearing 22; and a lower shaft portion 164 formed below the spacer portion 163 and fastened to the inner wheel 221 of the lower bearing 22.

[0034] The diameter D1 of the spacer portion 163 of the second worm gear shaft 16 is larger than the diameter D2 of the lower end shaft portion 164 and smaller than the inner diameter D3 of the outer wheel 222 of the lower bearing 22. (Ref) Figure 5 )

[0035] According to the present invention as described above, when the second worm gear shaft 16 is supported by the upper bearing 20 and the lower bearing 22, that is, when the upper shaft portion 162 is engaged with the inner wheel 201 of the upper bearing 20 and the lower shaft portion 164 is engaged with the inner wheel 221 of the lower bearing 22, the front end of the spacer portion 163 contacts and presses the inner wheel 221 of the lower bearing 20.

[0036] Therefore, according to the present invention, when the actuator is working, the second worm gear shaft 16 rotates, so that even if axial force is generated, the inner wheel 221 of the lower bearing 22 is pressed by the spacer portion 163, thereby preventing the inner wheel 221 of the lower bearing 22 from moving in the axial direction.

[0037] Furthermore, as the inner wheel 221 of the lower bearing 22 is pressed, the second worm gear shaft 16 is relatively lifted, and the inner wheel 201 of the upper bearing 20 is also pressed upward through the upper shaft portion 162, so that it will not move.

[0038] The reason for this is the following structural characteristics: as described above, the diameter D1 of the spacer portion 163 is greater than the diameter D2 of the lower end shaft portion 164 and smaller than the inner diameter D3 of the outer wheel 222 of the lower bearing 22.

[0039] Therefore, according to the present invention, the working noise caused by the movement of the inner wheels 201 and 221 of the upper bearing 20 and the lower bearing 22 will not be generated as in the past.

[0040] According to another embodiment of the present invention, such as Figure 7 The lower bearing 32 forms an inclination angle on the inner surfaces (contact surfaces with the bearing balls) of its inner wheel 321 and outer wheel 322 in a direction that faces each other across the bearing balls 323.

[0041] According to another embodiment of the present invention as described above, the inner wheel 321 of the lower bearing 32 is strongly supported by the outer wheel 322 along the axial direction.

[0042] Therefore, even if the inner wheel 321 is pressed by the spacer portion 163 of the second worm gear shaft 15, the axial load is distributed along the radial direction, thereby improving the durability of the lower bearing 30.

[0043] The second worm gear shaft 16 of the present invention, including the spacer portion 163, can be manufactured by a method of machining the base material bar 16', which will be described below.

[0044] like Figure 8 As shown, the manufacturing method of the second worm gear shaft 16 of the present invention may include: a cutting step (S1), cutting a continuous steel bar to a predetermined length to manufacture a base bar 16'; an upper shaft portion forming step (S2), performing a predetermined cutting process on the upper front end of the cut base bar 16' to form an upper shaft portion 162 that is snapped into the inner wheel 201 of the upper bearing 20; a lower shaft portion forming step (S3), performing a predetermined cutting process on the lower front end of the base bar 16' to form a lower shaft portion 164; a spacer portion forming step (S4), performing a predetermined cutting process on a predetermined section connected to the lower shaft portion 164 of the base bar 16' to form a spacer portion 163; and a screw portion forming step (S5), performing a cutting process on the section between the upper shaft portion 162 and the spacer portion 163 of the base bar 16' to form a screw portion 161.

[0045] In step S3 of forming the spacer portion, the diameter of the spacer portion 163 is larger than the diameter of the lower end shaft portion 162 and smaller than the inner diameter of the outer wheel 222 of the lower bearing 22.

[0046] In the second worm gear shaft manufacturing method of the present invention described above, an example is given of forming the upper shaft portion 162, the lower shaft portion, the spacer portion 163, and the screw portion 161 in sequence. Depending on the requirements, the processing sequence for forming each part can be different.

[0047] According to the second worm gear shaft manufacturing method of the present invention as described above, the base material bar 16' is divided into an upper shaft section, a spacer section, a lower shaft section, and a screw section, and simple cutting is performed on each section. In this way, the second worm gear shaft 16 can be manufactured, thereby improving productivity.

Claims

1. An actuator for an electric side pedal device, include: Drive motor; The first worm gear shaft transmits the driving force of the drive motor by reducing its speed; The first worm gear meshes with the first worm gear shaft; The second worm gear shaft is connected to the first worm gear and rotates together with the first worm gear; The second worm gear meshes with the second worm gear shaft; and The main shaft is connected to the second worm gear. The second worm gear shaft is supported by an upper bearing and a lower bearing. The actuator of the electric side pedal device is characterized in that the second worm gear shaft includes: Screw part; The upper shaft portion is formed above the screw portion and is fastened into the inner wheel that is connected to the upper bearing; A spacer portion, formed below the screw portion, is used to press the inner wheel of the lower bearing; and The lower end shaft portion is formed below the spacer portion and is fastened into the inner wheel of the lower bearing.

2. The actuator of the electric side pedal device according to claim 1, characterized in that, The diameter of the spacer portion of the second worm gear shaft is larger than the diameter of the lower shaft portion and smaller than the inner diameter of the outer wheel of the lower bearing.

3. The actuator of the electric side pedal device according to claim 2, characterized in that, The lower bearing has its inner and outer wheels separated by bearing balls and forming an angle of inclination along mutually opposing directions.

4. A method for manufacturing a second worm gear shaft for an actuator of an electric side pedal device, characterized in that, include: The cutting process involves cutting continuous steel bars to a specified length to manufacture the base material. In the upper shaft forming step, the upper front end of the cut base material bar is cut within a specified range to form the upper shaft that is snapped into the inner wheel of the upper bearing. In the lower end shaft forming step, the lower front end of the base material bar is cut within a specified range to form the lower end shaft. The spacer part forming step involves machining a predetermined section connected to the lower end shaft of the base material bar to form the spacer part; and In the screw part forming step, the area between the upper end shaft part and the spacer part of the base material bar is machined to form the screw part.

5. The method for manufacturing the second worm gear shaft of the actuator for the electric side pedal device according to claim 4, characterized in that, In the step of forming the spacer portion, the diameter of the spacer portion is larger than the diameter of the lower end shaft portion and smaller than the inner diameter of the outer wheel of the lower bearing.

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