Patent Application
20080040009
The foregoing and further features and advantages of the invention will become apparent from the following description of example embodiments with reference to the accompanying drawings, wherein the same or corresponding portions will be denoted by the same reference numerals and wherein:
Hereafter, embodiments of the invention will be described with reference to the accompanying drawings. In the description below, the same or corresponding components will be denoted by the same reference numerals. The functions and the names of the components having the same reference numerals are also the same. Accordingly, detailed description on the components having the same reference numerals will be provided only once below.
The shift-position control system 10 is used to change the shift-positions for a vehicle. The shift-position control system 10 includes a P-switch 20, a shift switch 26, a vehicle power supply switch 28, a vehicle control unit (hereinafter, referred to as an “EFI-ECU”) 30, a parking control unit (hereinafter, referred to as a “SBW (Shift-by-Wire)-ECU”) 40, an actuator (motor) 42, an encoder 46, a shift-position control mechanism 48, a display unit 50, a meter 52, and a drive mechanism 60. The shift-position control system 10 functions as a Shift-by-Wire shift-position changing apparatus that changes the shift-positions under electric control. More specifically, the shift-position control mechanism 48 is driven by the actuator 42 to change the shift-positions.
The vehicle power supply switch 28 is used to change the on/off state of an electric power supply for a vehicle. Any type of switch, for example, an ignition switch may be employed as the vehicle power supply switch 28. An instruction that the vehicle power supply switch 28 receives from, for example, the driver is transmitted to the EFI-ECU 30. For example, when the vehicle power supply switch 28 is turned on, electric power is supplied from an auxiliary battery (not shown), whereby the shift-position control system 10 is actuated.
The P-switch 20 is used to change the shift-position between P and Non-P. The P-switch 20 includes an indicator 22 that indicates the current shift-position ( P or Non-P) to the driver, and an input unit 24 that receives an instruction from the driver. The driver inputs an instruction to change the shift-position to P in the P-switch 20 through the input unit 24. The input unit 24 may be a momentary switch. The instruction from the driver, which is received by the input unit 24, is transmitted to the EFI-ECU 30, and also to the SBW-ECU 40 through the EFI-ECU 30. A component other than the P-switch 20 may be used to change the shift-position from Non-P to P.
The SBW-ECU 40 controls the actuator 42 that drives the shift-position control mechanism 48 to change the shift-position between P and Non-P. The SBW-ECU 40 causes the indicator 22 to indicate the current shift-position (P or Non-P). If the driver presses the input unit 24 when the shift-position is in Non-P, the SBW-ECU 40 changes the shift-position to P, and causes the indicator 22 to indicate that the current shift-position is in P.
The actuator 42 is formed of a switched reluctance motor (hereinafter, referred to as a “SR motor”), and drives the shift-position control mechanism 48 in accordance with an instruction from the SBW-ECU 40. The encoder 46 rotates together with the actuator 42, and detects the rotational state of the SR motor. The encoder 46 is a rotary encoder that outputs an A-phase signal, a B-phase signal and a Z-phase signal. The SBW-ECU 40 receives a signal from the encoder 46 to determine the rotational state of the SR motor, and controls a supply of electric power used to drive the SR motor.
The shift switch 26 is used to change the shift-position to Drive (hereinafter, referred to as D), Reverse (hereinafter, referred to as R), Neutral (hereinafter, referred to as N), or the Brake (hereinafter, referred to as B). When the shift-position is in P, the shift switch 26 is used to change the shift-position from P to Non-P. An instruction from the driver, which is received by the shift switch 26, is transmitted to the EFI-ECU 30. The EFI-ECU 30 executes the control to change the shift-positions in the drive mechanism 60 in accordance with the instruction from the driver, and causes the meter 52 to indicate the shift-position. In the first embodiment of the invention, the drive mechanism 60 is formed of a continuously variable speed-change mechanism. Alternatively, the drive mechanism 60 may be formed of a multi-speed speed-change mechanism.
The EFI-ECU 30 comprehensively controls the operation of the shift-position control system 10. The display unit 50 indicates an instruction, an alert, etc. provided from the EFI-ECU 30 or the SBW-ECU 40 to the driver. The meter 52 indicates the conditions of the vehicle components and the current shift-position.
The shift-position control mechanism 48 includes a manual shaft 102 that is rotated by the actuator 42, a detent plate 100 that rotates along with the manual shaft 102, a rod 104 that operates in accordance with the rotation of the detent plate 100, a parking gear 108 that is fixed to the output shaft of a transmission (not shown), a parking gear locking pawl 106 that is used to lock the parking gear 108, a detent spring 110 that restricts the rotation of the detent plate 100 to fix the shift-position at a predetermined shift-position, and a roller 112. The manual shaft 102 functions as a mechanical element according to the invention.
The detent plate 100 is driven by the actuator 42 to change the shift-positions. The manual shaft 102, the detent plate 100, the rod 104, the detent spring 110 and the roller 112 serve, in combination, as a shift-position changing mechanism. The encoder 46 obtains a discrete value corresponding to the amount by which the actuator 42 rotates. The shift-position changing mechanism functions as shift-position changing means or a shift-position changing unit according to the invention.
In the perspective view in
In the shift-position control system 10, the SBW-ECU 40 controls the amount by which the actuator 42 rotates so that the impact caused when the roller 112 of the detent spring 110 drops into an indentation after climbing over the crest 122 is reduced to reduce the load placed on the shift-position changing mechanism including the detent plate 100, the detent spring 110 and the manual shaft 102.
The shift position mechanism 48 is provided with emergency vehicle immobilizing actuator 72 that has a mechanism operated by the driver. With the emergency vehicle immobilizing actuator 72, it is possible to change the shift-positions even when electric power supply to the shift-position control system 10 is shut off due to a malfunction in a power supply system for a vehicle when the vehicle is at a standstill. The emergency vehicle immobilizing actuator 72 functions as a setting member according to the invention.
The emergency vehicle immobilizing actuator 72 includes a knob 72A that is pulled up by the driver, a rod 72B that transfers the force, with which the knob 72A is pulled up against a spring force, to a plate 72C, and a lug portion 72D that is fitted to the manual shaft 102 and that is engaged with the plate 72C, when needed, to rotate the manual shaft 102. As shown in
The lug portion 72D projects from the peripheral face of the manual shaft 102, and for example, it has a flat plate shape. As shown in
When the plate 72C is at the reference position that is reached when the rod 72B is operated downward to the fullest extent, the manual shaft 102 is rotated by the driving force of the actuator 42, and either Non-P or P may be selected. When the plate 72C is at the operated position that is reached when the rod 72 is operated upward to the fullest extent, even when the actuator 42 is driven, the rotation of the manual shaft 102 is restricted by the plate 72C, and the shift-position cannot be changed from P to Non-P. As indicated by the arrow P, moving the plate 72C from the reference position, at which the rod 72B is operated downward to the fullest extent, to the operated position at which the rod 72B is operated upward to the fullest extent, forcibly changes the shift-position from D to P. When the plate 72C is at the operated position that is reached when the rod 72B is operated upward to the fullest extent, the emergency vehicle immobilizing actuator 72 is in the operated state, that is, the emergency vehicle immobilizing actuator 72 has been pulled up by the driver.
When the emergency vehicle immobilizing actuator 72 is in the operated state, the knob 72A has been pulled up by the driver against the spring force. Accordingly, if the driver stops pulling up and releases the knob 72A, the plate 72C is moved to the reference position by the spring force, and the emergency vehicle immobilizing actuator 72 is no longer in the operated state. However, the shift-position is maintained at P. A component that applies a force to the plate 72C is not limited to a spring. Such force may be an electric force, an elastic force that is generated by a component other than a spring, a pressure, a magnetic force, etc. When the plate 72C is at the reference position, the shift-positions can be changed in a usual manner. A force for maintaining the shift-position at P may also be a spring force, an electric force, an elastic force that is generated by a component other than a spring, a pressure, a magnetic force, or the like.
The operation of the thus structured shift-position control system 10 will be described. When the vehicle is at a standstill, if a malfunction has occurred in the power supply system, for example, if an indicator of an instrument panel is entirely turned off although the ignition switch is not off, the Shift-by-Wire shift-position control system 10 cannot change the shift-position from Non-P to P. In a vehicle that includes an electric parking brake instead of a manual parking brake, the parking brake malfunctions as well.
In such a case, the driver pulls up the knob 72A to bring the emergency vehicle immobilizing actuator 72 in the operated state, to change the shift-position from Non-P to P. When the knob 72A is pulled up, the shift-position is changed to P, as shown in
As described above, with the shift-position control system 10 including the shift-position control apparatus, even when a malfunction has occurred in the electrical system of the vehicle equipped with the “Shift-by-Wire” shift-position changing apparatus, the shift-position is reliably changed from Non-P to P.
When the emergency vehicle immobilizing actuator 72 is in the operated state, the shift-position may be changed from Non-P to P and maintained at P. Alternatively, the shift-position may be changed from P to Non-P and maintained at Non-P.
The control system 1000 shown in
The shift-position control system 1000 shown in
Namely, the emergency vehicle immobilizing actuator 72 places the manual shaft 102, which is used to select the shift-position, into a predetermined rotational position. For example, the emergency vehicle immobilizing actuator 720 places the manual shaft 102 into a predetermined rotational position such that the shift-position is changed from Non-P to P and maintained at P, or the shift-position is changed from P to Non-P and maintained at Non-P. The types of a drive power source for changing the shift-positions and maintaining the shift-position are not limited to electric power supply sources and mechanical (pneumatic pressure, hydraulic pressure, spring, magnetic force, etc.) power supply sources as long as the power supply source is separate from the drive power source (auxiliary battery) for the actuator 42.
More specifically, the emergency vehicle immobilizing actuator 720 has the structure shown in
The emergency vehicle immobilizing actuator 720 includes an electric motor 720A, the rod 72B that transfers the driving force generated by the electric motor 720A to the plate 72C, and the lug portion 72D that is fitted to the manual shaft 102 and that is engaged with the plate 72C, when needed, to rotate the manual shaft 102. The electric motor 720A gradually moves the emergency vehicle immobilizing actuator 720 upward in the direction of the arrow P, in which the shift-position is changed to P, or moves the emergency vehicle immobilizing actuator 720 downward in the direction of the arrow Non-P, in which the shift-position is changed to Non-P. The electric motor 720A generates the driving force that is used to drive the emergency vehicle immobilizing actuator 720 instead of the operating force applied by the driver.
According to the second embodiment of the invention as well, when the electric motor 720A is not operated, the plate 72C is maintained at the reference position by the spring force, and the emergency vehicle immobilizing actuator 720 is no longer in the operated state.
The routine executed by the SBW-ECU 40 in
In step (hereinafter, simply referred to as “S”) 100, the SBW-ECU 40 monitors electric power supply in the shift system using a shift system power supply malfunction determination unit. Namely, the SBW-ECU 40 monitors whether electric power is properly supplied to the shift-position control mechanism 48 of the shift-position control system 10.
In S200, the SBW-ECU 40 determines whether there is a malfunction in the electric power supply in the shift system. If it is determined that there is a malfunction in the electric power supply in the shift system (“YES” in S200), S300 is executed. On the other hand, if it is determined that there is no malfunction (“NO” in S200), the routine ends.
In S300, the SBW-ECU 40 determines whether the actual shift-position is in Non-P. The determination is made based on a signal from a shift-position sensor. If it is determined that the shift-position is in Non-P (“YES” in S300), S400 is executed. On the other hand, if it is determined that the shift-position is in P (“NO” in S300), the routine ends.
In S400, the SBW-ECU 40 detects the vehicle speed V. In S500, the SBW-ECU 40 determines whether the vehicle speed V is equal to or lower than the threshold value V (TH). The threshold value V (TH) is set, for example, to a value close to zero. If it is determined that the vehicle speed V is equal to or lower than the threshold value V (TH) (“YES” in S500), S600 is executed. On the other hand, if it is determined that the vehicle speed V is higher than the threshold value V (TH) (“NO” in S500), the routine ends.
In S600, the SBW-ECU 40 outputs an operation instruction to the emergency vehicle immobilizing actuator 720. Then, as shown in
The operation of the shift-position control system 1000 that has the above-described structure and executes the above-described routine will be described below.
The electric power supply in the shift system is monitored (S100). If it is determined that a malfunction has occurred (“YES” in S200), the shift-position is in Non-P (“YES” in S300), and the vehicle is at a standstill (“YES” in S500), the emergency vehicle immobilizing actuator 720 is actuated (S600). At this time, the emergency vehicle immobilizing actuator 720 is operated to change the shift-position from Non-P to P. Namely, the electric motor 720A is controlled so that the rod 72B is moved upward.
With the shift-position control system 1000 including the shift-position control apparatus, even when a malfunction has occurred in the electric system (the auxiliary battery) of the actuator 42 that rotates the manual shaft 102 in the vehicle including the Shift-by-Wire shift-position changing apparatus, the shift-position is reliably changed from Non-P to P.
Hereafter, a modified example of the second embodiment of the invention will be described.
According to the modified example of the second embodiment of the invention, the following steps are executed in addition to the steps in the routine shown in
The shift-position control system 1000 according to the modified example of the second embodiment of the invention may be structured such that a spring force is not required.
If it is determined that there is a malfunction in the electric power supply in the shift system (“YES” in S200), and it is determined that the vehicle speed is higher than the threshold value V (TH) (“NO” in S500), the SBW-ECU 40 operates the emergency vehicle immobilizing actuator 720 to move the plate 72C from the operated position downward to the reference position. Namely, the plate 72C is maintained at the reference position. Thus, even when it becomes impossible to rotate the manual shaft 102 using the actuator 42 while the vehicle moves, the plate 72C is maintained at the reference position.
In the modified example, the driving force used to maintain the plate 72C at the reference position is not limited to the force generated by the electric motor. Such driving force may be a mechanically applied force, a pressure such as a pneumatic or a hydraulic pressure, a magnetic force, or a spring force as in the first embodiment of the invention.
At the reference position that is reached when the arc-shaped member 1720B pivots counterclockwise to the fullest extent, either Non-P or P may be selected by rotating the manual shaft 102 using the driving force of the actuator 42. At the operated position that is reached when the arc-shaped member 1720B pivots clockwise to the fullest extent, the rotation of the manual shaft 102 is restricted even when the actuator 42 is driven, and the shift-position cannot be changed from P to Non-P.
When the arc-shaped member 1720B pivots clockwise (the direction of the arrow P), the shift-position is forcibly changed from D to P. A lug portion 1720D projects from the peripheral face of the manual shaft 102, and has a flat plate shape. As shown in
When a malfunction has occurred, the arc-shaped member 1720B, which serves as an actuator, changes the shift-position from Non-P to P in response to the driver's operation as in the first embodiment of the invention, or using the electric motor as in the second embodiment of the invention.
The shift-position changing apparatus according to the invention may be applied to any one of an automatic transmission that executes the gear control in which the gear corresponding to the shift-position selected by the driver is used, and an automatic transmission that executes the shift-range control in which the gear corresponding to the shift-position selected by the driver and the gears lower than the selected gear are all used.
While the invention has been described with reference to example embodiments thereof, it is to be understood that the invention is not limited to the example embodiments or constructions. To the contrary, the invention is intended to cover various modifications and equivalent arrangements. In addition, while the various elements of the example embodiments are shown in various combinations and configurations, which are example, other combinations and configurations, including more, less or only a single element, are also within the spirit and scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-215961 | Aug 2006 | JP | national |
