Electronic shift lever

An electronic shift lever is provided and includes a housing which accommodates various components therein. A motor unit generates a driving force and a reduction unit is connected to the motor unit. The reduction unit is configured to increase the driving force generated from the motor unit. The motor unit and the reduction unit are accommodated inside the housing and are formed integrally with each other.

CROSS-REFERENCE TO RELATED APPLICATION

The application claims priority to Korean Patent Application No. 10-2019-0136118 filed on Oct. 30, 2019, the entire contents of which is incorporated herein for all purposes by this reference.

BACKGROUND

1. Field of the Disclosure

The present disclosure relates to an electronic shift lever, and more particularly, to an electronic shift lever in which a gearshift in a target shift stage range may be automatically operated within a shift range set according to a driving speed of a vehicle.

2. Discussion of Related Art

In general, a vehicle equipped with an automatic transmission allows a gearshift in a target shift range to be automatically operated by adjusting hydraulic pressure within a shift range set according to a driving speed of the vehicle. To perform shifting, the automatic transmission sets up a gear ratio using a hydraulic circuit, a planetary gear, and frictional elements. A transmission control unit (TCU) operates such components.

Meanwhile, unlike an existing mechanical shift system operated through the existing mechanical mechanism, a shift-by-wire (hereinafter, referred to as “SBW”) system is a shift system in which mechanism parts such as a cable, a mechanical manual valve, and a mechanical parking mechanism are removed. The SBW system is a system in which, when a lever sensor value generated during an operation of an electronic shift lever or a button is transferred to a TCU, a solenoid or an electric motor is operated by an electronic signal instructed by the TCU, and then, by the operation of the solenoid or the electric motor, oil pressure is applied to or shut off from a hydraulic circuit for each shift stage, whereby shift control may be electronically performed.

Therefore, an automatic transmission based on SBW delivers a driver's intention of shifting in the form of an electric signal to a TCU through a simple operation of an electronic shift lever or a button. Accordingly, shifting into a driving range (D), a reverse range (R), a neutral range (N), a parking range (P), and the like is easily performed. In addition, the size of the shift lever may be reduced to secure more space between a driver's seat and a passenger's seat.

An automatic transmission based on the conventional SBW includes a housing, a rotor core, a magnet yoke, and a sensor magnet. The rotor core and the magnet yoke are accommodated inside the housing, and the magnet yoke is assembled in a magnetized state on an upper portion of the rotor core. The sensor magnet is attached to the magnet yoke coupled to the upper portion of the rotor core through a bonding method. A magnetic force is delivered to a hall sensor positioned on a motor through the sensor magnet.

Meanwhile, the rotor core and the magnet yoke may be assembled in a mutually magnetized state, but for the rotor core and the magnet yoke to be assembled more firmly, a aperture may be formed in the upper portion of the rotor core to couple the magnet yoke to the aperture. Therefore, an additional operation process for forming the aperture in the upper portion of the rotor core is required. In addition, since an unnecessary space is formed inside the housing in addition to a space for installing the magnet yoke, there is a high possibility that a packaging problem occurs due to a full length of a product.

For the above-described reasons, in the related field, a method of reducing an additional operation process and a size of an automatic transmission is being sought, but until now, satisfactory results have not been obtained.

SUMMARY

The present disclosure is directed to providing an electronic shift lever which allows an additional operation process and a size of an automatic transmission to be reduced.

According to an aspect of the present disclosure, an electronic shift lever may include a housing which accommodates various components therein, a motor unit configured to generate a driving force, a reduction unit connected to the motor unit and configured to increase the driving force generated from the motor unit, and a printed circuit board (PCB) disposed on the motor unit and to which a Hall sensor is attached, wherein the motor unit and the reduction unit may be accommodated inside the housing and may be formed integrally with each other.

The motor unit may include a rotor core configured to generate the driving force, a hollow shaft rotated by the driving force of the rotor core due to the rotor core inserted to be disposed on an outer circumferential surface of the hollow shaft, a sensing plate disposed between the PCB and the reduction unit, and a sensor magnet attached to the sensing plate and sensed by the Hall sensor of the PCB, the reduction unit may include an output shaft in which the hollow shaft may be inserted to be disposed on an outer circumferential surface thereof, a bearing inserted between the hollow shaft and the output shaft, and a gear portion connected to the hollow shaft and the output shaft to deliver a driving force of the hollow shaft to the output shaft, and the sensing plate may be coupled between one end of the output shaft and one end of the hollow shaft.

The hollow shaft may include an eccentric portion formed on an outer circumferential surface in the one end direction thereof and may deliver the driving force of the rotor core to the gear portion through the eccentric portion. The gear portion may include an inner gear inserted to be disposed on the eccentric portion of the hollow shaft and an outer gear coupled to an outer circumferential surface of the inner gear, and the outer gear and the inner gear may be coupled to each other in a cycloid gear structure.

A wing or flange portion, through which a coupling groove passes, may be formed on an outer circumferential surface of the output shaft, and a coupling protrusion may be formed to extend downward from a position of a lower surface of the inner gear, which corresponds to the coupling groove, and may be inserted into the coupling groove. The sensing plate may include a plate portion which has a lower surface with which an end of the hollow shaft in one direction is in contact and has an upper surface to which the sensor magnet is attached, and an insertion portion having a cylindrical shape which extends downward from the plate portion.

An outer circumferential surface of the insertion portion may be in contact with an inner circumferential surface of the hollow shaft, and an inner circumferential surface of the insertion portion may be in contact with an outer circumferential surface of the output shaft. The bearing may include a double-row bearing disposed between an outer circumferential surface of the output shaft and an inner circumferential surface of the hollow shaft, and a single-row bearing disposed between an outer circumferential surface of the hollow shaft and an inner circumferential surface of the gear portion.

The double-row bearing may include two radial-type ball bearings which are rotatable in response to external forces in axial, radial, and tangential directions. The reduction unit may further include a reducer cover in which an outer gear is assembled in a press-fitting manner, and a knurled surface may be formed on a surface of the reducer cover on which the outer gear is press-fitted.

DETAILED DESCRIPTION

The advantages and features of the present disclosure and methods for accomplishing the same will be more clearly understood from exemplary embodiments described below with reference to the accompanying drawings. However, the present disclosure is not limited to the following exemplary embodiments but may be implemented in various different forms.

Rather, the present exemplary embodiments will make the disclosure of the present disclosure complete and allow those skilled in the art to completely comprehend the scope of the present disclosure. The present disclosure is only defined within the scope of accompanying claims.

Terms used in this specification are to describe the embodiments and are not intended to limit the present disclosure. As used herein, singular expressions, unless defined otherwise in contexts, include plural expressions. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including,” when used herein, specify the presence of stated components, steps, operations, and/or elements, but do not preclude the presence or addition of one or more other components, steps, operations, and/or elements.

Referring toFIGS.1to5, the electronic shift lever according to one exemplary embodiment of the present disclosure may include a housing100, a printed circuit board (PCB)200, a motor unit300, and a reduction unit400. The housing100accommodates various components such as the PCB200, the motor unit300, and the reduction unit400and blocks foreign materials from being introduced from the outside.

The housing100protects various components accommodated therein from an external impact. The PCB200is disposed in one end direction inside the housing100, and at least one Hall sensor210is disposed therein. The Hall sensor210attached to the PCB200may be configured to sense a change in magnetic flux of a sensor magnet332of the motor unit300to calculate a rotation angle of the motor unit300.

Meanwhile, when the Hall sensor210attached to the PCB200is able to sense the change in magnetic flux of the sensor magnet332, the Hall sensor210may also include various sensors. The motor unit300may be accommodated inside the housing100, and a driving force thereof may be generated according to an input signal of a controller configured to receive an input signal from a user. The motor unit300may include a rotor core310, a hollow shaft320, a sensing plate330, and the sensor magnet332. The rotor core310may be configured to generate the driving force in the motor unit300and has an aperture311formed to pass through a first end and a second end thereof. The hollow shaft320passes through the aperture311.

Meanwhile, the rotor core310according to one exemplary embodiment of the present disclosure may be a brushless direct current (BLDC) motor or a switched reluctance (SR) motor. The rotor core310may be inserted to be disposed on an outer circumferential surface of the hollow shaft320, and thus, the hollow shaft320may be rotated by the driving force of the rotor core310. The first end and the second end of an inside of the hollow shaft320communicate with each other.

An eccentric portion321may be formed in the hollow shaft320. The eccentric portion321may be formed on the outer circumferential surface in the second end direction of the hollow shaft320and allows the driving force of the rotor core310to be delivered to a gear portion430. The eccentric portion321protrudes from the outer circumferential surface in the second end direction of the hollow shaft320, and when the hollow shaft320may be rotated by the rotation of the rotor core310, the eccentric portion321presses the gear portion430.

The sensing plate330may be disposed under the PCB200and may be disposed at a first end of the hollow shaft320. In other words, the sensing plate330may be disposed between the PCB200and the hollow shaft320. The sensing plate330may be coupled between one end (e.g., a first end) of the hollow shaft320and one end (e.g., a first end) of an output shaft410of the reduction unit400. The sensing plate330may include a plate portion331and an insertion portion333.

One end of the hollow shaft320is in contact with a lower surface of the plate portion331, and the sensor magnet332, of which a magnetic force is sensed by the Hall sensor210attached to the PCB200, may be attached onto an upper surface of the plate portion331. The plate portion331may be formed to be thick, may have an outer diameter greater than an outer diameter of the hollow shaft320, and may have an area smaller than an area of the PCB200. In particular, the plate portion331may be disposed adjacent to the PCB200.

The Hall sensor210attached to the PCB200may be disposed in a region that overlaps the plate portion331. Thus, the Hall sensor210may be configured to sense the change in magnetic flux of the sensor magnet332attached to the plate portion331to calculate the rotation angle of the motor unit300. In addition, the plate portion331and the PCB200may be disposed adjacent to each other, and thus, the Hall sensor210attached to the PCB200may have a relatively high detection power with respect to the sensor magnet332to accurately sense the sensor magnet332. In addition, the sensor magnet332having low magnetism may be selectively used according to a use environment to lower costs of the sensor magnet332.

Furthermore, since the plate portion331may be formed to be thick, the housing100may be formed to have a small size, thereby making the electronic shift lever compact. The insertion portion333may be formed to have a cylindrical shape and extend downward from the lower surface of the plate portion331. The insertion portion333may have a cross-sectional shape that corresponds to cross-sectional shapes of the hollow shaft320and the output shaft410of the reduction unit400. As shown inFIG.3, the insertion portion333may be inserted between the hollow shaft320and the output shaft410. Thus, the insertion portion333prevents the sensing plate330from being separated from the hollow shaft320and the output shaft410.

The reduction unit400may be connected to the motor unit300to increase the driving force generated from the motor unit300, specifically, the rotor core310, and may include the output shaft410, a bearing, and the gear portion430. The hollow shaft320may be inserted to be disposed on an outer circumferential surface of the output shaft410, and a lower portion of the output shaft410may be connected to a detent lever (not shown) which changes parking (P), reverse (R), neutral (N), and driving (D) stages of a transmission according to an input signal of the controller.

In other words, when the driving force generated in the rotor core310may be delivered to the output shaft410through the gear portion430according to the rotation of the hollow shaft320, the output shaft410may be rotated to deliver the driving force of the rotor core310to the detent lever. Therefore, the output shaft410may be configured to rotate the detent lever by a specific position according to the driving force to change the P, R, N, and D stages of the transmission.

In addition, the output shaft410may have an outer diameter that is less than an inner diameter of the hollow shaft320. Accordingly, the outer circumferential surface of the output shaft410may be spaced apart from an inner circumferential surface of the hollow shaft320by a certain distance, and as shown inFIG.3, the insertion portion333may be fitted between one end direction (e.g., a first end direction) of the output shaft410and one end direction (e.g., a first end direction) of the hollow shaft320in a forcible fitting manner.

In other words, an inner circumferential surface of the insertion portion333is in contact with the outer circumferential surface of the output shaft410, and an outer circumferential surface thereof is in contact with the inner circumferential surface of the hollow shaft320. Due to such a coupling structure, the sensing plate330may be stably prevented from being separated from the hollow shaft320and the output shaft410by a vibration of the rotor core310or an external force applied from the outside.

The bearing may be inserted between the hollow shaft320and the output shaft410. When the gear portion430is rotated by the driving force of the rotor core310, the bearing allows the gear portion430to be rotated more easily from the housing100. In particular, due to the bearing, the gear portion430allows the hollow shaft320and the output shaft410to be strongly supported by the housing100.

Additionally, the bearing may include a double-row bearing421and a single-row bearing422. The double-row bearing421may be disposed between the outer circumferential surface of the output shaft410and the inner circumferential surface of the hollow shaft320and supports both of the hollow shaft320and the output shaft410. Thus, when the rotor core310is operated, the double-row bearing421minimizes the shaking of the hollow shaft320and the output shaft410, thereby securing robustness of the hollow shaft320and the output shaft410.

The double-row bearing421may include two radial-type ball bearings which are rotatable in response to external forces in axial, radial, and tangential directions. The single-row bearing422may be disposed between an outer circumferential surface of the hollow shaft320and an inner circumferential surface of the gear portion430and supports the hollow shaft320and the gear portion430together. Thus, when the rotor core310is operated, the single-row bearing422minimizes the shaking of the hollow shaft320and the gear portion430, thereby securing robustness of the hollow shaft320and the gear portion430.

The gear portion430may be connected to the hollow shaft320and the output shaft410to deliver the driving force of the rotor core310to the output shaft410and may be selectively rotated by the driving force of the rotor core310, which is generated according to an input signal of the controller. The gear portion430may include an inner gear431and an outer gear433. The inner gear431may be inserted to be disposed in a region of the eccentric portion321of the hollow shaft320and may be rotated concurrently when the hollow shaft320is rotated by the driving force of the rotor core310.

The outer gear433may be disposed on an outer circumferential surface of the inner gear431to be coupled to the inner gear431and may be rotated together with the inner gear431when the hollow shaft320is rotated by the driving force of the rotor core310. The inner gear431and the outer gear433may receive the driving force from the rotor core310and perform deceleration to increase the driving force. An amount of increase in the driving force may be determined according to a deceleration ratio set by parameters such as a module, a pitch circle diameter (PCD), and the number of teeth of the inner gear431and the outer gear433.

Meanwhile, the inner gear431and the outer gear433may be coupled to each other in a cycloid gear structure. Accordingly, as shown inFIG.4, the inner gear431may be eccentrically assembled with the outer gear433, and a driving force may be delivered to the output shaft410according to eccentricity. Meanwhile, a wing portion, in which a plurality of coupling grooves412are formed at equal intervals in a circumferential direction thereof, may be formed on the outer circumferential surface of the output shaft410.

Coupling protrusions432extend downward from positions of a lower surface of the inner gear431that correspond to the coupling grooves412. The coupling protrusions432may be inserted into the coupling grooves412. Thus, when the driving force generated in the rotor core310is delivered to the inner gear431through the hollow shaft320, the output shaft410may be rotated more easily according to the driving force of the hollow shaft320due to the coupling protrusion432inserted into the coupling groove412of the inner gear431.

Meanwhile, among the inner gear431and the outer gear433, the inner gear431may be rotated together with the output shaft410by rotation of the hollow shaft320, but the outer gear433should be fixed. Accordingly, the present disclosure may further include a reducer cover440. The reducer cover440supports the outer gear433, and the outer gear433may be assembled in a press-fitting manner.

In particular, as shown inFIG.5, a knurled surface may be formed on a surface of the reducer cover440, on which the outer gear433is press-fitted. In other words, when the outer gear433is assembled in the press-fitting manner, the reducer cover440may secure assembly robustness by a frictional force of the knurled surface, whereby the outer gear433may be stably fixed to the reducer cover440. The knurled surface may be formed on the surface of the reducer cover440, but when assembly robustness of a reduction gear and the outer gear433may be secured, according to a use environment or a processing method, the knurled surface may also be formed on the outer circumferential surface of the outer gear433and may also be formed in any one of the reducer cover440or the outer gear433.

As described above, in the electronic shift lever according to the present disclosure, the plate portion331and the PCB200may be disposed adjacent to each other, and thus, the Hall sensor210attached to the PCB200may have a relatively high detection power with respect to the sensor magnet332to more accurately sense the sensor magnet332. In addition, the sensor magnet332having low magnetism may be selectively used according to a use environment to reduce costs of the sensor magnet332. Since the plate portion331may be formed to be thin, the housing100may be formed to have a reduced size, thereby making the electronic shift lever compact.

The present disclosure is not limited to the above-described exemplary embodiments and various modifications may be made without departing from the spirit and scope of the present disclosure.