Transmission for vehicle

A transmission for a vehicle includes a transmission shift unit that receives a shift command of the vehicle, a driving unit that generates a driving force for causing the transmission shift unit to be switched between positions, and a controller configured to control the driving unit for causing the transmission shift unit to be switched between the positions depending on whether a preset condition is satisfied. In particular, the driving unit includes a first stator to generate magnetic flux, a first rotor including first inner permanent magnets and second inner permanent magnets and configured to be rotated by the magnetic flux transmitted to the first inner permanent magnets, outer permanent magnets, a second rotor disposed between the second inner permanent magnets and the outer permanent magnets, and a clutch unit disposed between the first rotor and the second rotor.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Korean Patent Application No. 10-2021-0086246 filed on Jul. 1, 2021, which application is incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a transmission for a vehicle, and more particularly, to a vehicle transmission with a transmission shift unit, positions of which are adjusted based on a preset condition.

2. Description of the Related Art

A transmission may vary gear ratios to maintain rotational speed of the engine of a vehicle over different vehicle speeds, enabling the driver to change the gear ratio of the transmission via manipulation of a shift lever.

In a manual shift mode, the driver changes the shift stage, and in an automatic shift mode, the shift stage is automatically changed depending on the vehicle speed when the driver selects the drive stage (D). Further, in a sports mode type transmission, both manual shifting and automatic shifting can be performed in a single transmission system. The sports mode type transmission system may be provided with a manual transmission next to an automatic transmission, allowing the driver to perform manual shifting by increasing or decreasing the gear stage while the system performs automatic shifting by default.

The shift lever is exposed inside the vehicle for the driver's manipulation, and most shift levers are exposed between the center fascia and the console box in the vehicle.

A driver normally selects a shift stage by moving the shift lever, which requires a space amounting to the movement trajectory of the shift lever, which in turn requires design endeavors to prevent the shift lever from interfering with the surroundings thereof.

Recently, a dial-type or button-type shift operation is available to reduce the space required for the shifting manipulation, thereby allowing more efficient use of the interior space of the vehicle and improving maneuverability of the transmissions.

SUMMARY

Aspects of the present disclosure provide a transmission for a vehicle with a transmission shift unit, positions of which are adjusted based on a preset condition.

In order to achieve the above object, a transmission for a vehicle according to an embodiment of the present invention may include a transmission shift unit configured to receive a shift command of the vehicle, a driving unit configured to generate a driving force for causing the transmission shift unit to be switched between positions, and a controller configured to control the driving unit for causing the transmission shift unit to be switched between the positions depending on whether a preset condition is satisfied. Further, the driving unit may include a first stator configured to generate magnetic flux, a first rotor including first inner permanent magnets and second inner permanent magnets that are disposed circumferentially at regular intervals along a rotational axis, and configured to be rotated by the magnetic flux transmitted to the first inner permanent magnets, outer permanent magnets that are provided in a different number than the second inner permanent magnets, a second rotor disposed between the second inner permanent magnets and the outer permanent magnets, and a clutch unit disposed between the first rotor and the second rotor.

Further, the clutch unit may include a base ring, one or more rollers disposed between the base ring and the second rotor, and one or more elastic parts provided on the base ring and configured to provide an elastic force to the rollers with respect to the base ring. The base ring may include seating surfaces configured to seat the rollers and to provide travel paths of the rollers, each of the elastic parts may be planar and elongated, and each of the seating surfaces may be inclined corresponding to a longitudinal direction of each elastic part and a travel path of each roller. The base ring may include seating surfaces configured to seat the one or more rollers and to provide the rollers with travel paths, respectively, and each of the one or more rollers may be pushed by the second rotor when rotating, toward a spot where the seating surface and an inner surface of the second rotor are spaced by decreasing distances.

The first rotor may include a rotating body and catch portions that protrude from the rotating body, and the first rotor may be rotated by a rotational force of the second rotor transmitted to the catch portions through the rollers. The first rotor may include a rotating body and catch portions that protrude from the rotating body, and each of the one or more rollers may be pushed by the catch portions when the first rotor rotates, toward a spot where the seating surface and the inner surface of the second rotor are spaced by increasing distances. The catch portions may be disposed circumferentially, and each of the catch portions may be disposed between adjacent ones of the rollers.

Further, the first rotor may be coupled to a rotor shaft formed elongated along a rotation axis, the rotor shaft being provided with a magnet holder that is configured to hold a magnetic substance. A magnetic sensor may be further provided to detect a rotation angle of the first rotor by using a magnetic force distribution of the magnetic substance.

Further, the controller may be configured to control the driving unit to cause the shift unit to be switched to a parking stage position when a parking condition is satisfied, and to control the driving unit to cause the shift unit to be switched to a stowed position when a stowing condition is satisfied. For example, the stowing condition may include at least one of turning off the vehicle or a user command input.

The controller may be configured to control, in response to the shift unit being switched from a first shift stage position to a second shift stage position when a shift condition is not satisfied, the driving unit to cause the shift unit to be switched to the first shift stage position. In addition, the controller may be configured to output a warning alarm in response to the shift unit being switched from the first shift stage position to the second shift stage position when the shift condition is not satisfied. The controller may be configured to determine whether the shift condition is satisfied by referring to at least one of an operation angle of a brake pedal or a driving speed of the vehicle.

Further, the second rotor may be configured to be intermittently rotated in response to being subjected to a force greater than a magnetic force between the second inner permanent magnets and the outer permanent magnets.

DETAILED DESCRIPTION

FIG.1is a diagram of a transmission10for a vehicle, according to an embodiment of the present disclosure.FIG.2is a diagram illustrating a transmission shift unit, also referred to as a shift unit100, the shift stage of which may be adjusted by a driving unit200.FIG.3is a diagram illustrating the shift unit100being switched to a stowed position by the driving unit200. Referring toFIG.1, the vehicle transmission10according to an embodiment of the present disclosure may include a shift unit100, a driving unit200, and a controller300.

The shift unit100may receive a shift command of the vehicle. Further, the shift unit100may include a shift body110and a shift lever120. The shift body110may rotate about a rotation axis Ax. The shift lever120may be elongated in one direction from the shift body110. For example, the shift lever120may be elongated in a direction perpendicular to the rotation axis Ax. As the shift body110rotates, the longitudinal direction of the shift lever120may be changed or switched. A user (e.g., a driver) may operate the shift unit100to change the shift stage of the vehicle. In some embodiments of the present disclosure, the shift stages selectable by the shift unit100may include a parking stage (P stage), a reverse stage (R stage), a neutral stage (N stage), and a drive stage (D stage).

The driving unit200may generate a driving force for repositioning or switching the transmission shift unit or, simply, shift unit100between the shift positions. For example, the driving unit200may generate a rotational force, by which the shift unit100may be turned and switched between the shift positions.

Referring toFIG.2, as the driving force of the driving unit200may be transmitted to the shift unit100, and the shift unit100may be switched to one of its shift positions among a parking stage (P stage), a reverse stage (R stage), a neutral stage (N stage), and a drive stage (D stage). Further, the transmission10for a vehicle according to some embodiments of the present disclosure may have a stowed position. Referring toFIG.3, the shift unit100may be switched from the parking stage position to the stowed position. The stowed position may refer a position in which the shift lever120of the shift unit100is disposed in parallel or near parallel to the ground (or substantially horizontal with respect to the orientation shown inFIG.3). In the stowed position, the shift stage of the shift unit100may maintain the parking stage. A separate stowing device (not shown) may be provided for stowing the shift lever120of the shift unit100. In such a case, the stowed position may mean that the shift lever120is stowed in the stowing device, and an unstowed position may mean that the shift lever120is exposed out of the stowing device.

The driving force of the driving unit200may be transmitted to the shift unit100by a drive transmission medium400.FIGS.1to3illustrate the driving force transmitting medium400provided in the form of a belt, which is exemplary, and the driving force transmitting medium400may be provided in various other forms such as a wire or a gear. Alternatively, the driving unit200may have its spindle directly connected to a spindle of the shift unit100for transmitting the driving force of the driving unit200to the shift unit100without relaying the same by the drive transmission medium400.

The controller300may be configured to control the driving unit200to cause the shift unit100to be switched between positions based on whether a preset condition is satisfied. Specifically, when the parking condition is satisfied, the controller300may be configured to control the driving unit200for switching the shift unit100to the parking stage position. For example, when the vehicle is turned off or turned on, the controller300may be configured to control the driving unit200to switch the shift unit100to the parking position. Alternatively, when the stowing condition is satisfied, the controller300may be configured to control the driving unit200to switch the shift unit100to the stowed position. For example, when the vehicle is turned off or a separate user command is inputted by using a button or other input means, the controller300may be configured to control the driving unit200to cause the shift unit100to be switched to the stowed position. Alternatively, if the shift unit100is switched from a first shift stage position to a second shift stage position while the shift condition is not satisfied, the controller300may be configured to control the driving unit200causing the shift unit100to be switched back to the first shift stage position. For example, the shift unit100, which is in the drive stage position, may be switched to the neutral stage position by a mistake of a user. In this case, the controller300may be configured to determine whether the reposition to the neutral stage is intentional or by mistake of the user, and upon determining that the reposition to the neutral stage is due to a mistake, it may be configured to control the driving unit200for switching the shift unit100back to the drive stage position.

FIG.4is a front perspective view of a driving unit200,FIG.5is a rear perspective view of the driving unit200, andFIG.6is a cross-sectional view taken along line A-A′ inFIG.4. Referring toFIGS.4to6, the driving unit200may include a first stator210, a second stator220, a first rotor230, outer permanent magnets240, a second rotor250, and a clutch unit260.

The first stator210may generate magnetic flux. The first stator210may include a plurality of coils provided separately from one another. Specifically, the first stator210may include a plurality of coils in a three-phase connection to generate magnetic flux by receiving power with different time offsets. Power may be sequentially supplied to the coils in a three-phase connection, and the energized coils may generate magnetic flux. A detailed description of the first stator210will be presented below with reference toFIGS.7and8.

The second stator220may support the outer permanent magnets240. The first stator210and the second stator220may be arranged adjacent along the rotation axis Bx. In the present disclosure, the rotation axis Bx may correspond to the rotation shaft for both the first rotor230and the second rotor250.

The first rotor230may include a rotating body231, first inner permanent magnets232, and second inner permanent magnets233. The first rotor230may be rotated by the magnetic flux transmitted from the first stator210. A detailed description of the first rotor230will be presented below with reference toFIGS.10to12.

A plurality of outer permanent magnets240may be disposed in the form of a ring externally of the first rotor230. Specifically, the outer permanent magnets240may be disposed concentrically with the second inner permanent magnets233about the rotation axis Bx where the second inner permanent magnets233are disposed. The number of the outer permanent magnets240may be different from the number of the second inner permanent magnets233. Specifically, the number of the outer permanent magnets240may be greater than the number of the second inner permanent magnets233.

The second rotor250may be disposed between the second inner permanent magnets233and the outer permanent magnets240, and it may rotate along a magnetic force path between the second inner permanent magnets233and the outer permanent magnets240. In particular, the second rotor250may rotate at revolutions per unit time (e.g., revolutions per minute, RPM) different from the number of revolutions per unit time of the first rotor230. The second rotor250may include a plurality of pole pieces252(seeFIG.13). The second rotor250may rotate with the magnetic force path formed by the pole pieces252between the second inner permanent magnets233and the outer permanent magnets240. Accordingly, the number of revolutions per unit time of the second rotor250with respect to the number of revolutions per unit time of the first rotor230may be determined by the number of first inner permanent magnets232, the number of second inner permanent magnets233, and the number of pole pieces252. The number of the outer permanent magnets240may be greater than the number of the second inner permanent magnets233first rotor230as mentioned above, wherein the number of revolutions per unit time of the second rotor250may be smaller than the number of revolutions per unit time of the first rotor230.

The clutch unit260may be disposed between the first rotor230and the second rotor250. As the clutch unit260receives a driving force from the first rotor230or the second rotor250, it may selectively transmit the rotational force of the first rotor230or the second rotor250. The operation of the clutch unit260may dictate the frictional force between the clutch unit260and the second rotor250. Upon receiving the driving force from the first rotor230, the clutch unit260may be spaced apart (e.g., disengaged) from the second rotor250or may be in contact with the second rotor250with a relatively low frictional force. In this case, the second rotor250may rotate nearly unaffected by the clutch unit260. On the other hand, upon receiving the driving force from the second rotor250, the clutch unit260may be in close contact (e.g., engaged) with the second rotor250with a relatively high frictional force. In this case, the driving force of the second rotor250may be transmitted via the clutch unit260to the first rotor230.

A detailed description concerning the linkage and power transmission of the first rotor230, the second rotor250, and the clutch unit260will be described below with reference toFIGS.20to25.

FIG.7is a view of a first stator210, andFIG.8is a view of a stationary body211of the first stator210. Referring toFIGS.7and8, the first stator210may include the stationary body211and coils212u,212v, and212w.

The stationary body211may include a rim211a, legs211b, and teeth211c. The rim211amay be provided in the form of a ring. A plurality of legs211bmay radially protrude internally from the rim211a. The coils212u,212v,212wmay be wound around the legs211b. To this end, the legs211bthat protrude from the rim211amay have a predetermined length or more.

The teeth211cmay be provided at the distal end of each of the plurality of legs211b. The teeth211cmay prevent separation of the coils212u,212v,212wwound around the legs211b. Additionally, the teeth211cmay form a magnetic flux path of magnetic flux generated in the coils212u,212v, and212w.

By way of example, nine (9) legs211bmay be provided. The nine legs211bmay be disposed on the rim211aso that the intervals between the adjacent legs211bare consistent.FIG.7illustrates that U-phase coils212u, V-phase coils212v, and W-phase coils212ware installed in the stationary body211. The U-phase coils212u, V-phase coils212v, and W-phase coils212wmay be sequentially wound around the legs211bin a clockwise or counterclockwise direction. The coils212u,212v,212wof the same phase may be interconnected electrically.FIG.7shows the provision of three U-phase coils212uthat are interconnected electrically, three V-phase coils212vthat are interconnected electrically, and three W-phase coils212wthat are interconnected electrically. Therefore, when electric power is supplied to one of the three U-phase coils212u, it may be also supplied to the other two U-phase coils212u, which similarly applies to the V-phase coils212vand the W-phase coils212w.

Among the plurality of coils in a three-phase connection, a first-phase coil may be understood as corresponding to the U-phase coil212u, a second-phase coil corresponding to the V-phase coil212v, and a third-phase coil corresponding to the W-phase coil212w.

The above description illustrates the legs211bas being nine, although some embodiments of the present disclosure may provide less or more than nine legs211b. The following description is principally based on nine legs211bfor illustration purposes.

FIG.9is a diagram for explaining the operation principle of the first stator210. Referring toFIG.9, the first stator210may be connected to a vehicle power source20through a switching unit500. The vehicle power source20may be a battery provided in the vehicle, but the vehicle power source20of the present disclosure is not limited to the battery.

The switching unit500may include a plurality of switches510to560. The plurality of switches510to560may include six switches. The plurality of switches510to560may include first to third switch groups connected in parallel. The first switch group may include the first switch510and the fourth switch540connected in series, the second switch group may include the second switch520and the fifth switch550connected in series, and the third switch group may include the third switch530and the sixth switch560connected in series.

A junction between the first switch510and the fourth switch540may be connected to, among the plurality of coils in a three-phase connection, a first-phase coil, i.e., the U-phase coils212u, a junction between the second switch520and the fifth switch550may be connected to a second-phase coil, i.e., the V-phase coils212v, and a junction between the third switch530and the sixth switch560may be connected to a third-phase coil, i.e., the W-phase coils212w.

The operation of each of the six switches510to560may be controlled by the controller300. The controller300may be configured to individually control the opening and closing of the six switches510to560. With individual operations of the switches510to560, the transmission may determine the allowing or breaking of the power supply from the vehicle power source20to each of the coils212u,212v, and212wprovided in the first stator210. For example, the operations of the switches510to560may cause the electric power to be supplied to a selected coil among the U-phase coils212u, the V-phase coils212v, and the W-phase coils212w.

The sequential supply of power may be performed in units of a pair of coils. For example, the operations of the switches510to560may sequentially establish a power supply circuit including a pair of coils, and power may be supplied to the pair of coils existing on that circuit. The coils in the pair may generate magnetic fluxes of different polarities, respectively. For example, one of the coils in the pair may generate an N-pole magnetic flux, and the other may generate an S-pole magnetic flux. One of the coils in the pair may apply a pushing force (e.g., a repulsive force) to the first rotor230, and the other may apply a pulling force (e.g., an attractive force) to the first rotor230.

The coil pairs may change sequentially. For example, after power is supplied to the U-phase coil212uand the V-phase coil212v, power may be supplied to the V-phase coil212vand the W-phase coil212w, followed by power being supplied to the W-phase coil212wand the U-phase coil212u, which proceeds repeatedly. The torque generated by changing coil pairs may rotate first rotor230.

FIG.10is a view of the rotating body231of the first rotor230,FIG.11is a view showing the rotating body231of the first rotor230installed with the first inner permanent magnets232and the second inner permanent magnets233, andFIG.12is a view looking in the direction of C inFIG.11. Referring toFIGS.10to12, the first rotor230may include the rotating body231, first inner permanent magnets232, and second inner permanent magnets233.

The rotating body231may be provided substantially in the form of a cylinder. The rotating body231may include a first rotating body portion231aand a second rotating body portion231b. The first rotation body portion231aand the second rotation body portion231bmay be disposed at different axial positions along the rotation axis Bx. As will be described below, the first rotating body portion231amay be coupled with the first inner permanent magnets232, and the second rotating body portion231bmay be coupled with the second inner permanent magnets233. As the first rotation body portion231aand the second rotation body portion231bare disposed at different axial positions along the rotation axis Bx, the first inner permanent magnets232and the second inner permanent magnets233may be disposed on the rotation body231at regular intervals along the rotation axis Bx.

The second rotating body portion231bmay be formed to have a diameter smaller than a diameter of the first rotating body portion231a. However, according to some embodiments of the present disclosure, the diameter of the first rotating body portion231amay be smaller than or equal to the diameter of the second rotating body portion231b.

Referring toFIG.12, a plurality of first inner permanent magnets232may be provided and coupled to the outer surface of the first rotating body portion231ain the form of a ring. The plurality of first inner permanent magnets232may be disposed with different (e.g., alternating) polarities thereof being adjacent to each other on the outer surface of the first rotating body portion231a. In other words, the permanent magnet of the S pole may be disposed adjacent to the permanent magnet of the N pole.FIG.12illustrates that the first rotor230is configured by including eight (8) first inner permanent magnets232, but this is merely illustrative and according to some embodiments of the present disclosure, different numbers may be selected for the first inner permanent magnets232. However, the number of the first inner permanent magnets232may be different from the number of the coils212u,212v,212winstalled in the first stator210.

A plurality of second inner permanent magnets233may be provided and coupled in the form of a ring to the outer surface of the second rotating body portion231b. The plurality of second inner permanent magnets233may be disposed with different polarities thereof being adjacent to each other on the outer surface of the second rotating body portion231b. In other words, the permanent magnet of the S pole may be disposed adjacent to the permanent magnet of the N pole.FIG.12illustrates that the first rotor230is configured to include two (2) second inner permanent magnets233, but this is merely illustrative and according to some embodiments of the present disclosure, different numbers may be selected for the second inner permanent magnets233. However, the number of the second inner permanent magnets233may be different from the number of the outer permanent magnets240installed in the second stator220.

The first rotor230may be rotated by the magnetic flux transferred to the first inner permanent magnets232thereof from the first stator210. The magnetic flux of the first stator210may generate a force for moving the first inner permanent magnets232, by which the first rotor230rotates.

FIG.13is a view of the second rotor250. Referring toFIG.13, the second rotor250may include a base251, pole pieces252, and a spindle253. The base251may be formed with a plane perpendicular to the rotation axis Bx of the second rotor250. The base251may include a central portion251aand an edge portion251b. The central portion251amay protrude from the edge portion251bin a direction parallel to the rotation axis Bx. The central portion251amay be formed with a recessed space that faces the first rotor230. The recessed space of the second rotor250may accommodate the clutch unit260therein.

The pole pieces252may be joined with the edge portion251b. A plurality of pole pieces252may be provided and formed to extend in one direction from the edge portion251b. The plurality of pole pieces252may have an elongated shape parallel to the rotation axis Bx of the second rotor250. The plurality of pole pieces252may be arranged in a ring shape about the rotation axis Bx of the second rotor250. In this case, the respective adjacent pole piece252among the plurality of pole pieces252may be disposed to be spaced apart from each other by a predetermined distance. The separation distance between adjacent pole pieces252may be equally applied to all adjacent pole pieces252.

The base251may be provided with a spindle253. Accordingly, when the second rotor250rotates, the spindle253provided on the base251may rotate along with the second rotor250. The spindle253may output the rotational force of the second rotor250. As the second rotor250rotates, an object coupled to the spindle253may rotate in unison with the second rotor250.

FIG.14is a view for explaining a rotation operation of the first rotor230with respect to the first stator210. Referring toFIG.14, the first stator210and the first rotor230may be disposed about the common rotation axis Bx. Accordingly, the central axis of the rim211aof the first stator210may coincide with the central axis of the first rotor230.

The plurality of coils212u,212v, and212wprovided in the first stator210may generate magnetic flux for each phase. For example, after the U-phase coil212ugenerates its magnetic flux, the V-phase coil212vmay generate its magnetic flux, and then the W-phase coil212wmay generate its magnetic flux. When the coil of one phase generates its magnetic flux, other coils may be stopped from generating their magnetic fluxes. The magnetic fluxes generated in the respective phase coils may be transmitted to the first inner permanent magnets232of the first rotor230and thereby may apply a force to the first inner permanent magnets232. Alternatively, the coils of the two phases may generate magnetic fluxes concurrently. For example, the U-phase coil212uand the V-phase coil212vmay simultaneously generate magnetic fluxes, or the V-phase coil212vand the W-phase coil212wmay simultaneously generate magnetic fluxes, or the W-phase coil212wand the U-phase coil212umay simultaneously generate magnetic fluxes. Here, one of the two coils that simultaneously generate magnetic fluxes may apply a pulling force to the pulling first rotor230, and the other may apply a pushing force thereto.

The first rotor230may rotate about the rotation axis Bx by the force applied to the first inner permanent magnets232thereof. With the magnetic fluxes generated rotationally by the respective phase coils212u,212v, and212wof the first stator210, the first rotor230may continuously rotate.

FIG.15is a view showing that the outer permanent magnets240are coupled to the second stator220. Referring toFIG.15, the outer permanent magnets240may be coupled to the second stator220and fixed thereto.

The second stator220may be provided in the shape of a ring. For example, the outer diameter of the second stator220may be equal or similar to the outer diameter of the first stator210. The plurality of outer permanent magnets240may be arranged in a ring shape along the inner surface of the second stator220.

The plurality of outer permanent magnets240may be arranged with different polarities thereof being adjacent to each other. In other words, the permanent magnet of the S pole may be disposed adjacent to the permanent magnet of the N pole.FIG.15shows that twenty (20) outer permanent magnets240are coupled to the second stator220, which is merely exemplary and some embodiments of the present disclosure may provide various numbers of outer permanent magnets240. However, the number of the outer permanent magnets240may be different from the number of the second inner permanent magnets233installed in the first rotor230. Specifically, the number of the outer permanent magnets240may be selected to be greater than the number of the second inner permanent magnets233installed in the first rotor230.

FIG.16is a view for explaining the coupling between the first rotor230, the second rotor250, and the outer permanent magnets240,FIG.17is a reduction ratio table, andFIG.18is a view for explaining a rotation operation of the second rotor250. Referring toFIG.16, the plurality of pole pieces252may be disposed between the second inner permanent magnets233and the outer permanent magnets240. The plurality of pole pieces252may form a magnetic force path between the second inner permanent magnets233and the outer permanent magnets240. In the present disclosure, the pole pieces252may be a magnetic substance. For example, the pole pieces252of the present disclosure may be a ferromagnetic material or a diamagnetic material. Accordingly, the pole pieces252disposed between the second inner permanent magnets233and the outer permanent magnets240may be simultaneously magnetized by the second inner permanent magnets233and the outer permanent magnets240to establish a magnetic force path therebetween.

The number of the plurality of pole pieces252provided in the second rotor250may be different from the numbers of the second inner permanent magnets233and the outer permanent magnets240. For example, the number of the plurality of pole pieces252may be different from the number of the second inner permanent magnets233and different from the number of the outer permanent magnets240.

The direction of the force that acts on each pole piece252may vary based on the positions of the surrounding ones of the second inner permanent magnets233and the outer permanent magnets240. In particular, a force in the circumferential direction of the second rotor250may act on some of the pole pieces252among the plurality of pole pieces252. When the first rotor230does not rotate, the resultant force in the circumferential direction that acts on the plurality of pole pieces252provided in the second rotor250may be zero. In this case, the second rotor250may not rotate. On the other hand, when the first rotor230rotates, the resultant force in the circumferential direction acting on the plurality of pole pieces252provided in the second rotor250may have a certain magnitude. The second rotor250may be rotated about the rotation axis Bx by the resultant force.

Compared to the number of revolutions per unit time of the first rotor230, the number of revolutions per unit time of the second rotor250may be configured to be small. Meanwhile, the force that acts on the second rotor250by the first rotor230that rotates for a unit time may be accumulated during that time, and thus the second rotor250may rotate with a higher torque than the first rotor230. The torque of the second rotor250may be determined by the number of second inner permanent magnets233, the number of outer permanent magnets240, and the number of pole pieces252.

Reduction ratios based on the number of the second inner permanent magnets233, the outer permanent magnets240, and the pole pieces252may be provided as shown in the reduction ratio table600ofFIG.17. Here, the reduction ratio represents a ratio of the number of revolutions per unit time of the second rotor250to the number of revolutions per unit time of the first rotor230. In the reduction ratio table600, nsrepresents the number of pole pieces252, p1represents the number of dipoles of the outer permanent magnets240, and p2represents the number of dipoles of the second inner permanent magnets233. Here, the dipole represents a pair of the N pole and the S pole among the plurality of magnets.

The reduction ratio may vary depending on which is the stationary body (“Fixed”) that is fixed and does not rotate, the input body (“Input”) that receives magnetic flux from the coils212u,212v,212w, and the output body (“Output”) that rotates and generates the resultant rotational force. The reduction ratio may be determined as p1/p2+1 when the outer permanent magnets240are the stationary bodies, the second inner permanent magnets233are the input bodies, and the pole pieces252are the output bodies. The reduction ratio may be determined as p1/p2when the pole pieces252are the stationary bodies, the second inner permanent magnets233are the input bodies, and the outer permanent magnets240are the output bodies. The reduction ratio may be determined as p2/p1+1 when the second inner permanent magnets233are the stationary bodies, the outer permanent magnets240are the input bodies, and the pole pieces252are the output bodies.

The above description illustrates that the outer permanent magnets240, the second inner permanent magnets233, and the pole pieces252are the stationary bodies, input bodies, and output bodies, respectively, but the pole pieces252, the second inner permanent magnets233, and the outer permanent magnets240may be the stationary bodies, input bodies, and output bodies, respectively, and the second inner permanent magnets233, the outer permanent magnets240, and the pole pieces252may be the stationary bodies, input bodies, and output bodies, respectively.

Referring toFIG.18, as the second rotor250rotates, a rotational force T thereof may be outputted via the spindle253. The rotational force of the plurality of pole pieces252may be concentrated on the base251, and the spindle253may rotate together with the base251about the rotation axis Bx. The spindle253may be coupled to the shift unit100with or without the drive transmission medium400, and as the spindle253rotates, the shift unit100may be rotated, thereby causing the shift unit100to be switched between the stage positions.

The base251of the second rotor250may cover a surface of the first rotor230that is perpendicular to the rotation axis Bx. In the present disclosure, the base251may be a paramagnet or a non-metal. Such a configuration may reduce the magnetic force by the first inner permanent magnets232provided in the first rotor230from acting on the shift unit100.

FIG.19is a view for explaining a manual rotation operation of the second rotor250. Referring toFIG.19, the second rotor250may rotate intermittently. When the first rotor230is stopped from rotating, the rotation of the second rotor250may be prevented by the magnetic force of the second inner permanent magnets233and the outer permanent magnets240. Meanwhile, when a force greater than the magnetic force between the second inner permanent magnets233and the outer permanent magnets240is applied on the second rotor250, the second rotor250may rotate intermittently. In this case, the second rotor250may perform intermittent rotation by a distance interval between the adjacent pole pieces252. For example, when the number of the pole pieces252is 16, the second rotor250may perform intermittent rotation at an interval of 360/16=22.5 degrees.

Referring toFIG.19, when a force greater than the magnetic force between the second inner permanent magnets233and the outer permanent magnets240is applied on the second rotor250that is fixed at the P1 position, the second rotor250may rotate to the P2 position. Likewise, the second rotor250stopped at the P2 position may be rotated to the P3 position and then rotated to the P4 position.

In the respective stop positions, the second rotor250may be prevented from rotating and fixed by the second inner permanent magnets233and the outer permanent magnets240. The force of the second inner permanent magnets233and the outer permanent magnets240for preventing rotation of the second rotor250may be the strongest at the stop positions and may be weaker in other positions. For example, the force of the second inner permanent magnets233and the outer permanent magnets240for preventing rotation of the second rotor250may increase as each pole piece252approaches the stop positions.

Due to the different forces of the second inner permanent magnets233and the outer permanent magnets240acting on the second rotor250between the stop positions and the non-stop positions, the second rotor250may perform the intermittent rotation by an articulated distance interval between the pole pieces252.

The second rotor250may be connected to the shift unit100. When the user operates the shift unit100in the manual rotation mode, the shift unit100may, in turn, cause the second rotor250to perform intermittent rotation. Additionally, when the user's rotation of the shift unit100is stopped, the second rotor250may be fixed in place by the second inner permanent magnets233and the outer permanent magnets240, which may also fix the shift unit100in place.

As described above, in response to the user's forced rotation of the shift unit100, the second rotor250may perform the intermittent rotation. This enables the shift unit100, when manually rotated by the user, to provide an intermittent shift feel by the driving unit200. Accordingly, the user may rotate the shift unit100with a sense of intermittent force (e.g., a haptic feedback, an operational feeling, etc.).

In the present disclosure, the second rotor250may rotate along with the first rotor230. With the clutch unit260provided between the first rotor230and the second rotor250, a force that is applied to the second rotor250may be transferred by the clutch unit260to the first rotor230such that the first rotor230may rotate along with the second rotor250. The power transmission relationship between the first rotor230, the second rotor250, and the clutch unit260will be described below with reference toFIGS.23to25.

Further,FIG.19is a view showing a rotation pattern when the pole pieces252are the output bodies. When the outer permanent magnets240are the output bodies, they may perform intermittent rotation at a distance interval between adjacent outer permanent magnets240.

FIG.20is a view for explaining the coupling between the first rotor230, the second rotor250, and the clutch unit260,FIG.21a rear perspective view of the base251of the second rotor250,FIG.22a view of the clutch unit260, andFIG.23a view illustrating the clutch unit260as installed between the first rotor230and the second rotor250. Referring toFIGS.20to23, the first rotor230, the second rotor250, and the clutch unit260may be coupled to each other.

As shown inFIG.21, the base251of the second rotor250may include a recessed space S. The clutch unit260may be accommodated in the recessed space S of the base251. The recessed space S may be provided with a ring-shaped inner surface. The inner surface may be in close contact with rollers262of the clutch unit260, and the mutual contact force between the inner surface of the base251and the rollers262of the clutch unit260may determine a friction force between the base251and the clutch unit260.

The first rotor230may include a coupling ring234and catch portions235. The coupling ring234may be formed to protrude in the shape of a ring from the rotating body231and may be coupled to the clutch unit260. The clutch unit260may be coupled to the coupling ring234to be rotatable with respect to the first rotor230.

The catch portions235may be formed to protrude from the rotating body231. The catch portions235may serve to transfer the driving force to or from the rollers262of the clutch unit260.

Referring toFIG.22, the clutch unit260may include a base ring261, the rollers262, and an elastic part263. The base ring261may be provided in the shape of a ring. The base ring261may be centrally formed with a through-hole and externally provided with a plurality of generally planar surfaces. A mechanical coupling may be established between the clutch unit260and the first rotor230by inserting the coupling ring234of the first rotor230into the clutch unit260through the through-hole. The rollers262may be seated on the outer surfaces of the base ring261. Hereinafter, the outer surface of the base ring261on which each roller262is seated is referred to as a seating surface. The seating surface may provide a travel path for the roller262. While being seated on the seating surface, the roller262may be movable along the seating surface. At this time, the roller262may move while rotating along the seating surface.

The rollers262may be disposed on the seating surfaces. The rollers262may be disposed between the base ring261of the clutch unit260and the second rotor250. As described above, the rollers262may move along the seating surfaces, and the frictional force between the roller262and the second rotor250may vary depending on the position of the seating surface.

Elastic parts263may be provided on the base ring261, and they may provide an elastic force to the rollers262against the base ring261. Each elastic part263may be planar and elongated to one side. The elastic force may act in a direction perpendicular to one surface of the elastic part263.

Referring toFIG.23, the seating surfaces of the elastic parts263may each be inclined corresponding to the longitudinal direction of each elastic part263and to the travel path of each roller262. One end of the elastic part263may be coupled to the base ring261, and the other end thereof may provide an elastic force to the roller262.

At least one roller262may be provided. The base ring261may include the seating surfaces, each providing a travel path for each roller262. For example, one roller262may be seated on one seating surface. The roller262may be disposed between the inner surface of the second rotor250and its seating surface of the base ring261. Accordingly, the roller262may be in contact with at least one of the inner surface of the second rotor250or its seating surface of the base ring261. Where the inner surface of the second rotor250is curved and the seating surface of the base ring261is flat, the distance between the inner surface and the seating surface may be different along the travel path of the roller262. For example, the distance from the center of the seating surface to the inner surface may be formed to be the greatest, and the distance from the edge of the seating surface to the inner surface may be formed to be the smallest. Accordingly, the frictional force between the roller262and the inner surface of the second rotor250may vary depending on the position of the seating surface on which the roller262is disposed.

The catch portions235of the first rotor230may be disposed with the rollers262adjacent in the circumferential direction placed therebetween. The catch portion235may be provided for each roller262. As will be described below, the catch portion235may push the roller262to move it along the seating surface, which occurs when the push by the catch portion235on the roller262exceeds the elastic force of the elastic unit263.

FIG.24is a view illustrating the clutch unit260as transmitting the rotational force of the second rotor250to the first rotor230. Referring toFIG.24, when the second rotor250is rotated, at least one roller262is pushed by the second rotor250to move toward a spot where the seating surface and the inner surface of the second rotor250are spaced by decreasing distances.

At least one roller262may move along the seating surface by the rotation of the second rotor250. Referring toFIG.24, when the second rotor250rotates clockwise, the upper roller262may move along the seating surface by the rotation of the second rotor250. The following will be described with the upper roller262as a reference.

When the driver manipulates the shift lever120to rotate the second rotor250, the roller262that is in contact with the inner surface of the second rotor250may rotate and move along the seating surface. At this time, the roller262may move to a point where the distance between the seating surface and the inner surface of the second rotor250decreases. For example, the roller262may move toward the edge of the seating surface. In this case, the frictional force between the roller262and the second rotor250may increase, and the clutch unit260may rotate in unison with the second rotor250.

As the clutch unit260rotates, the roller262may rotate about the rotation shaft Bx, and the roller262may push the catch portion235of the first rotor230. When the rotational force of the second rotor250is transmitted to the catch portion235through the roller262, the first rotor230may also rotate. As a result, when the second rotor250is rotated by the driver, the first rotor230may rotate along with the second rotor250. At this time, the first rotor230and the second rotor250may rotate at the same speed.

When the driver manipulates the shift lever120to rotate the second rotor250, as the first rotor230corotates with the second rotor250, the shift lever120may be subject to a resistive force which may provide the drive with a shift feel.

The roller262disposed at the lower side inFIG.24may be hardly affected by the rotation of the second rotor250. When the second rotor250rotates in the clockwise direction, the lower roller262may move toward the center of its seating surface. In this case, the decreasing frictional force between the roller262and the second rotor250may leave the roller262unaffected by the rotation of the second rotor250.

The above description concerns the relationship between two of the four rollers262provided in the clutch unit260and the second rotor250, but the other two rollers262may operate similarly.

FIG.25is a view illustrating that the first rotor230renders the friction to be removed or reduced between the clutch unit260and the second rotor250. Referring toFIG.25, when the first rotor230rotates, at least one roller262may be pushed by the catch portion235and move to a point where the distance increases between its seating surface and the inner surface of the second rotor250.

Referring toFIG.25, when the first rotor230rotates counterclockwise, the upper roller262may move along the seating surface by the rotation of the first rotor230. The following description is given with respect to the upper roller262.

When the first rotor230rotates counterclockwise, the catch portion235may push the roller262. When the force of the catch portion235is greater than the elastic force of the elastic part263, the roller262may move along the seating surface. The roller262that moves along the seating surface may part from the inner surface of the second rotor250, which prevents the rotational force of the first rotor230from being transmitted via the clutch unit260to the second rotor250. This means that the second rotor250may rotate exclusively by the mutual magnetic force between the first rotor230and the outer permanent magnets240irrespective of the clutch unit260.

The transmission10for a vehicle according to some embodiments of the present disclosure may provide an automatic parking stage repositioning function (RTP; Return To Park). The automatic parking-stage repositioning indicates a function by which the shift unit100is automatically repositioned to the parking stage (P stage) or switched to the stowed position. For example, when the vehicle is turned off while the shift unit100is at a non-parking stage, the transmission10may cause the shift unit100to be repositioned to the parking stage (P stage) and/or switched to the stowed position.

With the automatic parking stage repositioning function, the second rotor250connected to the shift lever120may be rotated. To rotate the second rotor250, the first rotor230may be rotated. The clutch unit260, which is disposed between the first rotor230and the second rotor250, preferably distances itself from attenuating the rotational force of the first rotor230. As described above, when the first rotor230rotates, since the rollers262of the clutch unit260part from the second rotor250, the rotational force of the first rotor230may be applied to the second rotor250unattenuated by the clutch unit260.

FIG.26is a view illustrating the coupling between the first rotor230and a rotor shaft270, andFIG.27is a view illustrating a magnetic sensor280that detects the rotation angle of the first rotor230. Referring toFIGS.26and27, the first rotor230may be coupled to the rotor shaft270elongated along the rotation axis Bx.

The rotor shaft270may be coupled to and corotate with the first rotor230. A magnet holder271may be provided on the rotor shaft270. A magnetic substance272may be supported by the magnet holder271. The magnetic substance272may generate a magnetic force. The magnetic force generated by the magnetic substance272may be detected by the magnetic sensor280.

The magnetic sensor280may detect the rotation angle of the first rotor230by using the magnetic force distribution of the magnetic substance272. For example, the magnetic sensor280may output the rotation angle of the first rotor230as a linear signal. Since the linear signal includes continuous rotation angles based on the positions of the first rotor230, the transmission according to the present disclosure may detect the rotation angles of the first rotor230by using the data outputted by the magnetic sensor280.

In some embodiments, the magnetic sensor280may be provided separately from the first rotor230. For example, the magnetic sensor280may be fixed to a housing (not shown) enclosing the driving unit200. When the first rotor230rotates, the magnetic substance272may rotate with respect to the magnetic sensor280, and the magnetic force distribution detected by the magnetic sensor280may vary. The magnetic sensor280may utilize the magnetic force distribution to detect the rotation angle of the first rotor230.

The rotation angle of the first rotor230that is detected by the magnetic sensor280may be transmitted to the controller300which then may rotate the first rotor230by referring to the rotation angle of the first rotor230.

FIG.28is a flowchart for a method of outputting a shift signal by the controller300. Referring toFIG.28, the controller300may be configured to output a shift signal that corresponds to the input shift command. The driver may input a shift command of the vehicle by using the shift unit100. The controller300may be configured to receive the shift command (S710). The controller300may be configured to determine whether the received shift command satisfies a shift condition (S720). For example, the controller300may be configured to determine whether the received shift command is by the driver's intention or by mistake.

The controller300may be configured to determine whether the shift condition is satisfied by referring to the driving state of the vehicle. Additionally, the controller300may be configured to determine whether the shift condition is satisfied by referring to at least one of an operation angle of a brake pedal and a driving speed of the vehicle.

For example, the controller300may be configured to determine that the shift condition is not satisfied upon receiving a shift command toward the drive stage or reverse stage when the gear shift stage of the vehicle is the parking stage with the operation angle of the brake pedal being less than or equal to a threshold angle. Alternatively, the controller300may be configured to determine that the shift condition is not satisfied upon receiving a shift command toward the reverse stage or the parking stage when the gear shift stage of the vehicle is the drive stage with the driving speed of the vehicle exceeding a threshold speed.

When the shift condition is satisfied, the controller300may be configured to output a shift signal (S730). For example, the controller300may be configured to output a shift signal once the shift unit100is switched from the first shift stage position to the second shift stage position and when the shift condition is satisfied. The outputted shift signal may be transmitted to a transmission (not shown) to change the shift stage.

On the other hand, when the shift condition is not satisfied, the controller300may be configured to prevented from outputting a shift signal. For example, the controller300may be configured to output a warning alarm once the shift unit100is switched from the first shift stage position to the second shift stage position and when the shift condition is not satisfied (S740).

Additionally, when the shift condition is not satisfied, the controller300may be configured to return the shift lever120to the previous position (S750). For example, once the shift unit100is switched from the first shift stage position to the second shift stage position and when the shift condition is not satisfied, the controller300may be configured to control the driving unit200causing the shift lever120to be switched to the first shift stage position.

As described above, due to the controller300configured to operate by taking account of the shifting condition, an inadvertent or unintended input of shift command of the shift unit100by the driver may be prevented from causing the shift unit100to perform a transmission operation, thereby ensuring a more reliable vehicle operation.

According to embodiments of the present disclosure, the transmission for a vehicle as described above has advantages as follows.

First, with the non-contact type driving unit used, the transmission can reduce the noise due to rotation and provide the user with an improved shift feel. Second, no separate part is required in implementing an automatic return-to-park (RTP) function. Third, by employing a two-way clutch, the transmission can provide the user with an improved shift feel while implementing the RTP function. Fourth, by comparing the driving state of the vehicle and the shift operation, the transmission can determine whether the shift operation is incorrect such that safer driving of the vehicle may be facilitated. Fifth, the transmission can precisely control the driving unit by detecting an accurate rotation angle of the rotor shaft by using a magnetic sensor.

However, the effects of the embodiments are not restricted to the ones set forth herein. The above and other effects of the embodiments will become more apparent to one of daily skill in the art to which the embodiments pertain by referencing the claims.