Patent Application
20090100954
The disclosure of Japanese Patent Application No. 2007-253344 filed on Sep. 28, 2007 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
The present invention relates to an automatic transmission control unit.
There exists a vehicle mounted with a shift-by-wire system equipped with an actuator 130 that changes a travel range of a vehicle automatic transmission 140, and a shift-by-wire control circuit (referred to as an SBW-ECU below) 110 that controls the actuator 130 based on a required range selected by a driver, as shown in
However, in the conventional shift-by-wire system above, the actuator 130, the SBW-ECU 110, and the AT-ECU 120 being separately accommodated, and the SBW-ECU 110 and the AT-ECU 120 respectively having similar circuit functions including power sources and CAN interfaces, also results in an increased number of parts and manufacturing costs. Furthermore, since the actuator 130, the SBW-ECU 110, and the AT-ECU 120 are connected via the plurality of connectors 111, 112, 121, 132 by the harnesses 102, 103, 113, it is necessary to avoid contact failures and the like to secure high reliability. Noise countermeasures using shielding wire must also be enacted for the harness 113 through which a drive current of a motor 131 flows.
A shift-by-wire system that integrates the actuator and the SBW-ECU has been proposed in Japanese Patent Application Publication No. JP-A-2007-10042 as a countermeasure. According to this shift-by-wire system, the actuator and the SBW-ECU are stored in one case, which enables downsizing.
According to the shift-by-wire system described in Japanese Patent Application Publication No. JP-A-2007-10042, however, the AT-ECU is stored in a separate case, which leaves room for further downsizing, and furthermore, the SBW-ECU and the AT-ECU have similar circuit functions as well as a wire harness electrically connecting the SBW-ECU and the AT-ECU. This results in an increased number of parts and manufacturing costs.
Vehicles are constantly subjected to vibrations. In a control unit integrating the actuator, the SBW-ECU, and the like, the operation of the actuator, which is a heavy body, may generate vibrations with respect to an ECU. Sufficient vibration resistance must therefore be secured. However, the shift-by-wire system described in Japanese Patent Application Publication No. JP-A-2007-10042 does not take into consideration such problems.
The present invention was devised in light of the foregoing problems, and it is an object of the present invention to provide an automatic transmission control unit that enables downsizing and a reduction in manufacturing costs, and also has good vibration resistance. The present invention can also achieve various other advantages.
According to an exemplary aspect of the invention, an automatic transmission control unit includes an actuator that changes a travel range of an automatic transmission; a shift-by-wire control circuit that controls the actuator in order to change the travel range of the automatic transmission to a selected range selected by a driver; an automatic transmission control circuit that controls a shift speed of the automatic transmission by at least a travel range position signal; and a control unit case that encloses the actuator, the shift-by-wire control circuit, and the automatic transmission control circuit, and is fixed by a fixing member to an automatic transmission case, wherein: the actuator is disposed within the control unit case on an automatic transmission case side, and the shift-by-wire control circuit and the automatic transmission control circuit are disposed within the control unit case on a side opposite the automatic transmission case side.
According to an exemplary aspect of the invention, an automatic transmission control unit includes an actuator that changes a travel range of an automatic transmission; a shift-by-wire control circuit that controls the actuator in order to change the travel range of the automatic transmission to a selected range selected by a driver; an automatic transmission control circuit that controls a shift speed of the automatic transmission by at least a travel range position signal; and a control unit case that encloses the actuator, the shift-by-wire control circuit, and the automatic transmission control circuit, and is fixed by a fixing member to an automatic transmission case, wherein: the actuator is disposed within the control unit case on a side where the control unit case is fixed to the automatic transmission case, and the shift-by-wire control circuit and the automatic transmission control circuit are disposed on a side surface of the control unit case opposite to the side where the control unit case is fixed to the automatic transmission case.
According to an exemplary aspect of the invention, an automatic transmission control unit includes an actuator that changes a travel range of an automatic transmission; a shift-by-wire control circuit that controls the actuator in order to change the travel range of the automatic transmission to a selected range selected by a driver; an automatic transmission control circuit that controls a shift speed of the automatic transmission by at least a travel range position signal; and a control unit case that encloses the actuator, the shift-by-wire control circuit, and the automatic transmission control circuit, and is fixed by a fixing member to an automatic transmission case, wherein: the control unit case is divided into a first storage portion that accommodates the actuator and a second storage portion that accommodates the shift-by-wire control circuit and the automatic transmission control circuit, and the first storage portion is adjacent to the automatic transmission case.
Various exemplary aspects of the invention will be described with reference to the drawings, wherein:
First and second embodiments that realize an automatic transmission control unit according to the present invention will be described below with reference to the accompanying drawings. As
The control unit 1 is provided with an actuator 20 and a control circuit mechanism 50. The actuator 20 is provided with a motor 21 that changes a travel range (such as P, R, N, D, D1, and D2) of the automatic transmission 6, while the control circuit mechanism 50 includes one printed circuit board 51 mounted with a shift-by-wire control circuit (referred to as an SBW-ECU below) 53, an automatic transmission control circuit (referred to as an AT-ECU below) 56, and the like as will be explained later (see
As
A bus bar 14, which serves as a conductor, conducts the motor drive current, and an end of the bus bar 14 is soldered to a land 14a of the printed circuit board 51 that is connected with an IC of the motor drive circuit 54. In addition, the bus bar 14 passes through the inside of the separation wall 11a, and another end of the bus bar 14 projects downward from the separation wall 11a and is connected with the motor 21 of the actuator 20. A signal conducting wire 15 transfers a signal detected by the position sensor 38 to the SBW-ECU 53, and an end of the signal conducting wire 15 is soldered to a land 15a of the printed circuit board 51 that is connected with an IC of the SBW-ECU 53. In addition, the signal conducting wire 15 passes through the inside of the separation wall 11a, and another end of the signal conducting wire 15 projects downward from the separation wall 11a and is connected with the position sensor 38.
Inside the case body 10, a ball screw shaft 30 is arranged parallel to the motor 21 and both ends of the ball screw shaft 30 are rotatably and axially supported on the main bracket 24 via bearings 31, 32. A front end side of the ball screw shaft 30 is fixed with a large gear 28 that meshes via the small gear 26 and an intermediate gear 27. The small gear 26, the intermediate gear 27, and the large gear 28 structure the reduction mechanism 22. Note that in the present embodiment, the rotation of the motor 21 decelerated by the small gear 26, the intermediate gear 27, and the large gear 28 is transferred to the ball screw shaft 30. However, the rotation of the motor 21 may be decelerated by a planetary gear, a worm gear, or the like, and then transferred to the ball screw shaft 30.
The ball screw shaft 30 is threadedly engaged with a ball nut 33. Both ends of an engagement rod 34 that extends parallel to the ball screw shaft 30 are fitted to the main bracket 24. A C-shaped engagement portion 35 that protrudes toward an outer periphery of the ball nut 33 is engaged with the engagement rod 34, and the ball nut 33 is held movable in an axial direction with respect to the main bracket 24. Thus, rotation of the motor 21 is decelerated by the reduction mechanism 22 and transferred to the ball screw shaft 30 and rotation of the ball screw shaft 30 is converted into axial motion of the ball nut 33 by the ball screw shaft 30, the ball nut 33, and the like.
An end of a manual shaft 36 projects inside the lower storage portion 10a and is rotatably supported on the case body 10. A base end portion of an arm 37 is fitted to the manual shaft 36 with a relative rotation of the arm 37 thus regulated and the arm 37 supported capable of oscillation. A distal end of the arm 37 branches into two and extends toward both sides of the ball nut 33, where respective concave portions 37a are formed on the distal ends. Through engagement of the concave portions 37a with an engagement shaft 33a provided extending toward both sides of the ball nut 33, the arm 37 is engaged with relative movement thereof in the axial direction of the ball screw shaft 30 regulated. The ball screw shaft 30, the ball nut 33, the arm 37, the engagement shaft 33a, the concave portion 37a, and the like structure the motion conversion mechanism 23. In addition, an end of the manual shaft 36 is attached with the position sensor 38.
Another end of the manual shaft 36 is connected with the range changeover mechanism 40 subject to driving by the actuator 20, as shown in
The detent mechanism 41 is structured from the detent lever 42, a detent spring 43, and an engagement roller 44. The detent lever 42 integrally rotates with the manual shaft 36 and the arm 37. Accordingly, the detent lever 42 rotates in the directions of arrows C and D with the manual shaft 36 serving as the center of rotation. The detent lever 42 is also provided with a through hole 42b that is engaged with a portion of a parking mechanism (not shown). The position sensor 38, which is attached to an end of the manual shaft 36, detects a rotational position of the detent lever 42 so as to detect a current position of the spool 48. A potentiometer, for example, may be used as the position sensor 38, with the potentiometer outputting a voltage in accordance with a rotational angle of the manual shaft 36. The range position (P-position, R-position, N-position, and D-position) can thus be detected as a zone of a predetermined width depending on the voltage level output from the potentiometer.
A description follows below regarding an operation of the SBW-ECU 53 and the actuator 20 in the control unit 1 with the above structure. When the driver operates the shift lever 4, a shift signal based on the selected range selected is input to the SBW-ECU 53 via the signal terminal 13b of the connector 13. A motor drive current based on the shift signal is then supplied from the SBW-ECU 53 to the motor 21 via the bus bar 14.
Accordingly, the motor 21 is driven in a predetermined driving direction, and rotational motion of the output shaft of the motor 21 is decelerated by the reduction mechanism 22 and transferred to the ball screw shaft 30 supported on the main bracket 24. Rotation of the ball screw shaft 30 moves the ball nut 33, whose rotation is regulated by engagement of the engagement rod 39 and the engagement portion 35, in the axial direction to thus rotate the arm 37 around the manual shaft 36. Rotation of the manual shaft 36 rotates the detent lever 42, and the spool 48 is moved via the shift portion 42a.
The SBW-ECU 53 stops rotation of the motor 21 when an output voltage of the position sensor 38 reaches a predetermined value. Once rotation of the motor 21 is stopped, the detent lever is rotated due to the actions of the detent spring 43, the engagement roller 44, and the like, and then held at a predetermined position. In this manner, the spool 48 is changed, which changes the travel range of the automatic transmission 6.
Actions of the AT-ECU 56 will be outlined next. The AT-ECU 56 is input with information indicating an operation state such as the engine speed from the engine ECU 2 via the signal terminal 13b of the connector 13. Based on such information, the AT-ECU 56 outputs to the automatic transmission 6 a control signal that controls various valves of the hydraulic control device of the automatic transmission 6. The engagement states of the clutches and brakes are thus changed to change the shift state.
In the control unit 1 according to the first embodiment, regarding the arrangement of the actuator 20, the SBW-ECU 53, and the AT-ECU 56, the actuator 20 is disposed and fixed on an automatic transmission case side within the control unit case 1A, which is fixed by a fixing member 10c to the automatic transmission case 6A, whereas the SBW-ECU 53 and the AT-ECU 56 are disposed on a side far from the automatic transmission case 6A opposite the actuator 20. Therefore, in a vehicle subject to constant vibration, vibrations of the heavy actuator 20 can be suppressed and good stability achieved. In other words, the case body 10 of the control unit case 1A fixed with the actuator 20 is fixed to the automatic transmission case 6A by the fixing member 10c, which is a bolt or the like, that passes through the attachment hole 10b. Therefore, the heavy actuator 20 can be reliably fixed to the automatic transmission case 6A. Operation of the actuator may generate conductive foreign bodies and possibly cause a short circuit in an ECU electronic component; however, the risk of such occurrences can be reduced.
The actuator 20 and the control circuit mechanism 50, which includes the SBW-ECU 53 and the AT-ECU 56, are accommodated within one control unit case 1A that includes the upper storage portion 12a and the lower storage portion 10a, which are vertically divided by the separation wall 11a. There is thus no need to provide respective onboard spaces, and similar circuit functions can also be used in common. The lower storage portion 10a accommodates the heavy actuator 20, and the upper storage portion 12a accommodates the lightweight control circuit mechanism 50. Therefore, good stability can be achieved in a vehicle subject to constant vibration. In addition, the actuator 20 structured from the motor 21, the reduction mechanism 22, the motion conversion mechanism 23, and the like, is fixed by the main bracket 24 made of metal separate from the case body 10 to the case body 10 using four bolts 25. Accordingly, the control unit 1 of the first embodiment is capable of achieving downsizing and a reduction in manufacturing costs, and also has good vibration resistance. In particular, mounting the SBW-ECU 53 and the AT-ECU 56 on one printed circuit board 51 in the control unit 1 enables the easy realization of a compact space and the common use of similar circuit functions. Furthermore, since wiring for the actuator 20 and the SBW-ECU 53 is accommodated in one case, the actuator 20 cannot be forcibly driven from outside, which can help prevent theft of the vehicle. Also, in the control unit 1, the storage portions divided by the separation wall 11a respectively accommodate the actuator 20, and the SBW-ECU 53 and the AT-ECU 56. Therefore, lubricant present in the actuator 20, wear particles generated from the reduction mechanism 22 and so forth can be prevented from penetrating to the storage portion where the SBW-ECU 53 and the AT-ECU 56 are accommodated.
In the control unit 1, the separation wall 11a is embedded with the bus bar 14 that electrically connects the actuator 20 and the printed circuit board 51. Therefore, the actuator drive current can flow through the bus bar 14 instead of an inner layer pattern of the printed circuit board 51, thereby downsizing the printed circuit board 51 and also eliminating the need for shielding wire as a noise countermeasure.
The automatic transmission control unit of the second embodiment has the structure shown in
The side lid 73 side of the case body 71 serves as a separation wall 71a. An end of the separation wall 71a is formed integrated with the connector 13 identical to that of the first embodiment, and projects toward a rear surface direction in
In the control unit 70 according to the second embodiment, the actuator 20 and the control circuit mechanism 50, which includes the SBW-ECU 53 and the AT-ECU 56, are accommodated within one control unit case 70A that includes the first storage portion 71b and the second storage portion 73a, which are laterally divided by the separation wall 71a. There is thus no need to provide respective onboard spaces, and similar circuit functions can also be used in common. The heavy actuator 20, which is controlled by the SBW-ECU 53 and changes the travel range of the automatic transmission 6, is disposed and fixed on the automatic transmission case 6A side within the control unit case 1A, which is fixed by the fixing member 71c to the automatic transmission case 6A. Meanwhile, the control circuit mechanism 50 that is more lightweight than the actuator 20 is disposed on a side surface of the control unit case 70A. Therefore, in a vehicle subject to constant vibration, vibrations of the heavy actuator can be suppressed and good stability achieved. Accordingly, the control unit 70 of the second embodiment is capable of achieving downsizing and a reduction in manufacturing costs, and also has good vibration resistance. Other structures, operations, and effects are identical to the first embodiment.
The control units 1, 70 in the present invention were described in the context of the first and second embodiments; however, the present invention is not limited to such, and may be applied with modification as appropriate provided that such modifications do not contradict the technical concept of the present invention.
The automatic transmission control unit according to the present invention is suitable for use as an automatic transmission control unit, which includes an actuator that changes a travel range of an automatic transmission for a vehicle; a shift-by-wire control circuit that controls the actuator based on a selected range selected by a driver; and an automatic transmission control circuit that controls various valves of a hydraulic control device of the automatic transmission.
According to an exemplary aspect of the invention, a heavy actuator, which is controlled by a shift-by-wire control circuit and changes a travel range of an automatic transmission, is disposed and fixed on an automatic transmission case side within a control unit case, which is fixed by a fixing member to an automatic transmission case. Meanwhile, the shift-by-wire control circuit and an automatic transmission control circuit, which are more lightweight than the actuator, are disposed on a side opposite the actuator far from the automatic transmission case. Therefore, in a vehicle subject to constant vibration, vibrations of the heavy actuator can be suppressed and good stability can be achieved. In addition, the actuator, the shift-by-wire control circuit, and the automatic transmission control circuit are accommodated within one case. There is thus no need to provide respective onboard spaces, and similar circuit functions can also be used in common. Accordingly, the automatic transmission control unit is capable of achieving downsizing and a reduction in manufacturing costs, and also has good vibration resistance. Furthermore, since wiring for the actuator, the shift-by-wire control circuit, and the automatic transmission control circuit is accommodated in one case, the actuator cannot be forcibly driven from outside, which can help prevent theft of the vehicle.
According to an exemplary aspect of the invention, a heavy actuator, which is controlled by a shift-by-wire control circuit and changes a travel range of an automatic transmission, is disposed and fixed on an automatic transmission case side within a control unit case, which is fixed by a fixing member to the automatic transmission case. Meanwhile, the shift-by-wire control circuit and an automatic transmission control circuit, which are more lightweight than the actuator, are disposed on a side surface of the control unit case. Therefore, in a vehicle subject to constant vibration, vibrations of the heavy actuator can be suppressed and good stability can be achieved. In addition, the actuator and a control unit including the shift-by-wire control circuit and the automatic transmission control circuit are accommodated within one case. There is thus no need to provide respective onboard spaces, and similar circuit functions can also be used in common. Accordingly, the automatic transmission control unit is capable of achieving downsizing and a reduction in manufacturing costs, and also has good vibration resistance. Furthermore, since wiring for the actuator, the shift-by-wire control circuit, and the automatic transmission control circuit is accommodated in one case, the actuator cannot be forcibly driven from outside, which can help prevent theft of the vehicle.
According to an exemplary aspect of the invention, the control unit case has an attachment hole, and is fixed to the automatic transmission case. Therefore, the heavy actuator can be reliably fixed to the automatic transmission case and vibration resistance improved.
According to an exemplary aspect of the invention, a control circuit mechanism including the shift-by-wire control circuit and the automatic transmission control circuit is fixed to a surface opposite a surface on an actuator side of a separation wall that divides an interior of the control unit case into two storage portions. Therefore, in an automatic transmission control unit where the actuator, the shift-by-wire control circuit, and the automatic transmission control circuit are integrated, operation of the actuator may generate conductive foreign bodies and possibly cause a short circuit in an ECU electronic component; however, the risk of such occurrences can be reduced.
According to an exemplary aspect of the invention, the heavy actuator is disposed in a lower storage portion on an automatic transmission case side within the control unit case, which is fixed by the fixing member to the automatic transmission case. Meanwhile, the shift-by-wire control circuit and the automatic transmission control circuit, which are more lightweight than the actuator, are disposed in an upper storage portion or a side storage portion. Therefore, in a vehicle subject to constant vibration, good stability can be achieved. Since the actuator and both control circuits are disposed in separate storage portions, even if operation of the actuator generates conductive foreign bodies, it is possible to prevent short-circuiting of electronic components of both control circuits.
According to an exemplary aspect of the invention, the shift-by-wire control circuit and the automatic transmission control circuit structure a control circuit mechanism mounted on one printed circuit board. Therefore, a compact space and the common use of similar circuit functions can be easily realized.
According to an exemplary aspect of the invention, the upper storage portion and the lower storage portion or the side storage portion are divided by a separation wall, and a conductor that electrically connects the actuator and the printed circuit board is embedded in the separation wall. Therefore, an actuator drive current can flow through the conductor instead of an inner layer pattern of the printed circuit board, thereby downsizing the printed circuit board and also eliminating the need for shielding wire as a noise countermeasure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-253344 | Sep 2007 | JP | national |
