Patent Application
20140083247
The present invention relates to a manual transmission applied to a vehicle which has an internal combustion engine and an electric motor as power sources, and more particularly to a manual transmission applied to a vehicle which includes a friction clutch disposed between the output shaft of the internal combustion engine and the input shaft of the manual transmission.
Conventionally, there has been widely known a so-called hybrid vehicle which includes an engine and an electric motor as power sources (see, for example, Japanese Patent Application Laid-Open (kokai) No. 2000-224710). In such a hybrid vehicle, a structure can be adopted in which the output shaft of the electric motor is connected to one of the output shaft of the internal combustion engine, the input shaft of a transmission, and the output shaft of the transmission. In the following description, drive torque from the output shaft of the internal combustion engine will be referred to as “engine drive torque,” and drive torque from the output shaft of the electric motor as “motor drive torque.”
In recent years, there has been developed a power transmission control apparatus applied to a hybrid vehicle which includes a manual transmission and a friction clutch (hereinafter referred to as an “HV-MT vehicle”). A term “manual transmission” used herein refers to a transmission which does not include a torque converter and whose gear stage is selected in accordance with the shift position of a shift lever operated by a vehicle driver (the manual transmission may be abbreviated as MT). Also, a term “friction clutch” used herein refers to a clutch which is interposed between the output shaft of the internal combustion engine and the input shaft of the manual transmission and which is configured such that the engagement state of a friction plate changes in accordance with the operation quantity of a clutch pedal operated by the driver.
In the following description, a configuration is assumed in which the output shaft of the electric motor is connected to the input shaft of the transmission or the output shaft of the transmission in a power transmissible manner. The “ratio of the rotational speed of the input shaft of the transmission to the rotational speed of the output shaft of the transmission” will be referred to as “transmission speed reduction ratio” and the “ratio of the rotational speed of the electric motor to the rotational speed of the output shaft of the transmission” will be referred to as “motor speed reduction ratio”.
In the manual transmission applied to HV-MT vehicle, it is preferable to decrease or increase the rotational speed of the electric motor in relation to the rotational speed of the drive wheels as necessary in order to enable the drive wheels to stably produce satisfactory drive torque on the basis of the motor drive torque. A conceivable method of realizing this is providing a motor speed change mechanism which changes the motor speed reduction ratio without changing the gear stage of the manual transmission (i.e., without changing the transmission speed reduction ratio).
In the case where such a motor speed change mechanism is provided, the transmission of torque from the output shaft of the electric motor to the output shaft of the transmission (i.e., the drive wheels) must be interrupted temporarily when the motor speed reduction ratio is changed. Accordingly, a shock (a change in acceleration in the front-rear direction of the vehicle) is unavoidably generated as a result of the change in the motor speed reduction ratio. Generation of such a shock provides unpleasant feel to the vehicle driver.
An object of the present invention is to provide a manual transmission for an HV-MT vehicle which includes a motor speed change mechanism capable of changing the motor speed reduction ratio and which makes a driver less likely to perceive a shock produced as a result of changing of the motor speed reduction ratio.
A manual transmission according to the present invention includes an input shaft (Ai) for receiving power from an internal combustion engine and an output shaft (Ao) for outputting power to drive wheels of the vehicle. This manual transmission includes a transmission speed change mechanism (M1) and a motor speed change mechanism (M2).
The transmission speed change mechanism (M1) operates, when a driver moves a shift operation member (SL) on a shift pattern to each of shift completion positions corresponding to a plurality of gear stages (1-st to 6-th), so as to establish a “power transmission system (line) between the input shaft and the output shaft such that the transmission speed reduction ratio is set to a value corresponding to a corresponding gear stage.” The motor speed change mechanism (M2) establishes a power transmission system (line) between the input or output shaft and the electric motor and changes the “motor speed reduction ratio” without changing the “transmission speed reduction ratio.” The “motor speed reduction ratio” may be changed between two values, or may be changed among three or more values.
The feature of the manual transmission according to the present invention resides in that the motor speed change mechanism (M2) is configured to change the “motor speed reduction ratio” when the position of the shift operation member passes through a predetermined position on the shift pattern other than the shift completion positions.
In the manual transmission of the present invention, when the driver changes or sets the gear stage, the driver must operate the shift operation member on the shift pattern. In general, a human being becomes less likely to perceive a shock or the like from the outside, when he or she performs some operation. The above-mentioned configuration is adopted in view of this fact.
According to the above-described configuration, the “motor speed reduction ratio” is changed while the driver is operating the shift operation member. In other words, the driver receives a shock generated as a result of changing of the “motor speed reduction ratio,” while the driver is operating the shift operation member. Accordingly, the driver becomes less likely to perceive the shock.
In the manual transmission, movement of the shift operation member to each of the shift completion positions corresponding to the plurality of gear stages is achieved by movement of the shift operation member to a corresponding selection position achieved by a selection operation which is an operation of the shift operation member in the left-right direction of the vehicle in a state in which no power transmission system (line) is established between the input and output shafts, and subsequent movement of the shift operation member from the corresponding selection position to the corresponding shift completion position achieved by a shift operation which is an operation of the shift operation member in the front-rear direction of the vehicle.
In this case, the “motor speed reduction ratio” may be changed when the shift operation member which moves in the front-rear direction of the vehicle during the shift operation passes through a predetermined position (other than shift completion positions) in the front-rear direction of the vehicle. More preferable, the “motor speed reduction ratio” is changed when the shift operation member which moves in the left-right direction of the vehicle during the selection operation passes through a predetermined position in the left-right direction of the vehicle.
Now, a case is assumed in which the “motor speed reduction ratio” is changed during the selection operation of the shift operation member. In this case, preferably, the motor speed reduction ratio is set to a first speed reduction ratio when the position of the shift operation member in the left-right direction of the vehicle moves from a first region (Hi region) on one side of the predetermined position located toward to the shift completion positions of gear stages for high speed travel to a second region (Lo region) on the other side of the predetermined position located toward to the shift completion positions of gear stages for low speed travel, and the motor speed reduction ratio is set to a second speed reduction ratio which is smaller than the first speed reduction ratio when the position of the shift operation member in the left-right direction of the vehicle moves from the second region to the first region.
By virtue of this configuration, when a gear stage for low speed travel is selected, the “motor speed reduction ratio” is set to a larger value, whereby the amplification factor of the motor drive torque is increased. Therefore, a large drive torque based on the motor drive torque can be obtained when the vehicle travels at a relatively low speed. As a result, the electric motor can be made smaller in size. On the other hand, when a gear stage for high speed travel is selected, the “motor speed reduction ratio” is set to a smaller value, whereby the rotational speed of the electric motor relative to the vehicle speed can be decreased. Accordingly, the rotational speed of the motor can be restricted to a range in which the energy efficiency is high when the vehicle travels at a relatively higher speed. As a result, a high energy efficiency can be maintained when the vehicle travels at a relatively higher speed.
An example of a power transmission control apparatus (hereinafter referred to as “present apparatus”) of a vehicle which includes a manual transmission M/T according to an embodiment of the present invention will now be described with reference to the drawings. As shown in
First, the overall structure of the present apparatus will be described. The engine E/G is a well known internal combustion engine, such as a gasoline engine which uses gasoline as fuel, or a diesel engine which uses light oil as fuel.
The manual transmission M/T is a transmission which does not include a torque converter and whose gear stage is selected in accordance with the shift position of a shift lever SL operated by a driver. The manual transmission M/T has an input shaft Ai for receiving power from an output shaft Ae of the engine E/G, an output shaft Ao for outputting power to drive wheels of the vehicle, and an MG shaft Am for receiving power from the motor generator M/G. The input shaft Ai, the output shaft Ao, and the MG shaft Am are disposed in parallel with one another. The MG shaft Am may be the output shaft of the motor generator M/G itself or may be a shaft which is parallel to the output shaft of the motor generator M/G and is connected with the output shaft of the motor generator M/G via a gear train in a power transmissible manner. The structure of the manual transmission M/T will be described in detail later.
The friction clutch C/T is disposed between the output shaft Ae of the engine E/G and the input shaft Ai of the manual transmission M/T. The friction clutch C/T is a well known clutch configured such that the engagement state of a friction plate (more specifically, the axial position of the friction plate, which rotates together with the input shaft Ai, in relation to a flywheel, which rotates together with the output shaft Ae) changes in accordance with an operation quantity (depression amount) of a clutch pedal CP operated by the driver.
The engagement state of the friction clutch C/T (the axial position of the friction plate) may be mechanically adjusted in accordance with the operation quantity of the clutch pedal CP, by making use of a link mechanism or the like which mechanically connects the clutch pedal CP to the friction clutch C/T (the friction plate). Alternatively, the engagement state of the friction clutch C/T may be electrically adjusted by making use of drive force of an actuator which operates in accordance with the operation quantity of the clutch pedal CP detected by a sensor (a sensor P1 to be described later) (by a so-called by-wire scheme).
The motor generator M/G has one of well known structures (e.g., an AC synchronous motor), and its rotor (not illustrated) rotates together with the MG shaft Am. In the following description, drive torque from the output shaft Ae of the engine E/G will be referred to as “EG torque,” and drive torque from the MG shaft Am (torque from the output shaft of the motor generator M/G) will be referred to as “MG torque.”
The present apparatus includes a clutch operation quantity sensor P1 which detects the operation quantity (depression amount, clutch stroke, etc.) of the clutch pedal CP, a brake operation quantity sensor P2 which detects the operation quantity (depression force, presence/absence of operation, etc.) of a brake pedal BP, an accelerator operation quantity sensor P3 which detects the operation quantity (accelerator opening) of an accelerator pedal AP, and a shift position sensor P4 which detects the position of the shift lever SL.
Moreover, the present apparatus includes an electronic control unit (hereinafter simply referred to as the “ECU”). On the basis of information, among others, from the above-mentioned sensors P1 to P4 and other sensors, etc., the ECU controls the EG torque by controlling the amount of fuel injected into the engine E/G (opening of its throttle valve) and controls the MG torque by controlling an inverter (not shown).
The structure of the manual transmission M/T will be described specifically with reference to
As shown in the shift pattern of
The manual transmission M/T includes sleeves S1, S2, S3, and Sm. The sleeves S1, S2, and S3 are fitted onto corresponding hubs which rotate together with the output shaft Ao such that the sleeves cannot rotate relative to the corresponding hubs but can move axially relative to the corresponding hubs. The sleeve S1 is used to switch the MT speed reduction ratio between values corresponding to “1-st” and “2-nd.” The sleeve S2 is used to switch the MT speed reduction ratio between values corresponding to “3-rd” and “4-th.” The sleeve S3 is used to switch the MT speed reduction ratio between values corresponding to “5-th” and “6-th.” The sleeve Sm is fitted onto a hub which rotates together with the MG shaft Am such that the sleeve Sm cannot rotate relative to the hub but can move axially relative to the hub. The sleeve Sm is used to switch the MG speed reduction ratio between values corresponding to “Hi” and “Lo.”
As shown in
The S&S shaft shown in
First, the changeover of the MG speed reduction ratio will be described with reference to
The changeover of the MG speed reduction ratio is performed when the position of the shift lever SL moves from the “Hi region” to the “Lo region” (or vice versa) during the selection operation (i.e., when the position of the shift lever SL passes through the “predetermined position”). Specifically, as shown in
On the other hand, as shown in
As is understood from the foregoing, the MG speed reduction ratio is changed from “Hi” (a smaller value) to “Lo” (a larger value) when the position of the shift lever SL moves from the “Hi region” to the “Lo region” during a selection operation. Accordingly, for example, when a shift operation is performed such that the position of the shift lever SL moves from the “N position” to the “shift completion position for 1-st (or 2-nd),” the MG speed reduction ratio is switched from “Hi” to “Lo” in the course of movement of the shift lever SL from the “N position” to the “1-2 selection position.” After that point in time, the MG speed reduction ratio is maintained at “Lo” so long as the position of the shift lever SL is maintained in the “Lo region” (i.e., 1-st or 2-nd is selected).
Since the MG speed reduction ratio is set to “Lo” (a larger value) when a gear stage for low speed travel (1-st or 2-nd) is selected, the amplification factor of the MG torque increases. Therefore, a large drive torque can be obtained on the basis of the MG torque when the vehicle travels at a relatively lower speed. As a result, the motor generator M/G can be made smaller in size.
Meanwhile, when the position of the shift lever SL moves from the “Lo region” to the “Hi region” during a selection operation, the MG speed reduction ratio is changed from “Lo” to “Hi.” Accordingly, for example, when a shift operation is performed such that the position of the shift lever SL moves from the “shift completion position for 2-nd (or 1-st) to the “shift completion position for 3-rd (or 4-th),” the MG speed reduction ratio is switched from “Lo” to “Hi” in the course of movement of the shift lever SL from the “1-2 selection position” to the “N position.” Thereafter, the MG speed reduction is maintained at “Hi” so long as the position of the shift lever SL is maintained in the “Hi region” (i.e., one of N and 3-rd through 6-th is selected).
Since the MG speed reduction ratio is set to “Hi” (a smaller value) when a gear stage for high speed travel (3-rd through 6-th) is selected, the rotational speed of the motor generator M/G relative to the vehicle speed can be decreased. Accordingly, the rotational speed of the motor generator M/G can be restricted to a range in which the energy efficiency is high when the vehicle travels at a relatively higher speed. As a result, a high energy efficiency can be maintained when the vehicle travels at a relatively higher speed.
As described above, the manual transmission M/T includes an MG speed change mechanism M2 which can selectively set the MG speed reduction ratio to one of two values; i.e., “Hi” and “Lo.” The MG speed change mechanism M2 is composed of the stationary gears Gmlo and Gmho, the idle gears Gmli and Gmhi, the sleeve Sm, the fork shaft FSm, etc.
Now, the changeover of the MT speed reduction ratio will be briefly described with reference to
When the shift lever SL moves to the “shift completion position for 1-st” as shown in
In this state, the sleeve S1 is engaged with an idle gear G1o provided on the output shaft Ao. The idle gear G1o is always meshed with a stationary gear G1i provided on the input shaft Ai. As a result, a power transmission system corresponding to “1-st” for the EG torque is established between the input shaft Ai and the output shaft Ao through the gears G1i and G1o. Namely, the MT speed reduction ratio is equal to the value of (the number of gear teeth of the idle gear G1o/that of the stationary gear G1i) (=“1-st”).
When the shift lever SL is in any of the “shift completion positions for “2-nd” through “6-th” as shown in
As described above, the manual transmission M/T includes an MT speed change mechanism M1 which can selectively set the MT speed reduction ratio to one of six values corresponding to “1-st” through “6-th.” The MT speed change mechanism M1 is composed of the stationary gears GNi, the idle gears GNo, the sleeves S1 through S3, the fork shafts FS1 through FS3, etc. (N: 1 through 6).
As mentioned above, as indicated by thick solid lines in
Control of the engine E/G by the present apparatus is generally conducted as follows. When the vehicle is stopped or “N” is selected, the engine E/G is maintained in a stop state in which fuel injection is not conducted. The engine E/G is started (fuel injection is started), for example, when any one of “1-st” through “6-th” is selected in the state in which the engine E/G is stopped. During a period during which the engine E/G is operated (fuel injection is conducted), the EG torque is controlled in accordance with the accelerator opening, etc. The engine E/G is stopped again when “N” is selected or the vehicle is stopped during the period during which the engine E/G is operated.
Control of the motor generator M/G by the present apparatus is generally conducted as follows. When the vehicle is stopped or “N” is selected, the motor generator M/G is maintained in a stop state (MG torque=0). For example, when any one of “1-st” through “6-th” is selected in the state in which the motor generator M/G is stopped, the MG torque is controlled in accordance with the accelerator opening, the clutch stroke, etc. When “N” is selected or the vehicle stopped, the motor generator M/G is stopped again.
As described above, in the manual transmission M/T according to the embodiment of the present invention, while a driver is performing the selection operation of the shift lever SL (operation in the left-right direction of the vehicle), the MG speed reduction ratio is changed. In other words, while performing the selection operation of the shift lever SL, the driver receives a shock generated as a result of changing of the MG speed reduction ratio. In general, a human being becomes less likely to perceive a shock or the like from the outside, when he or she performs some operation. For the above-described reason, the present manual transmission M/T makes the driver less likely to perceive the shock generated as a result of changing of the MG speed reduction ratio.
The present invention is not limited to the above-described embodiment, and various modifications may be adopted without departing from the scope of the present invention. For example, although the sleeves S1, S2 and S3 (and the corresponding idle gears) are all provided on the output shaft Ao in the above-mentioned embodiment, they may be provided on the input shaft Ai. Alternatively, some of the sleeves S1, S2, S3 (and the corresponding idle gears) may be provided on the output shaft Ao, and the remaining sleeve(s) (and the corresponding idle gear(s)) may be provided on the input shaft Ai.
Although the MG shaft Am is connected to the output shaft Ao in a power transmissive manner in the above-mentioned embodiment, the MG shaft Am may be connected to the input shaft Ai in a power transmissive manner. In the above-mentioned embodiment, the MG speed change mechanism M2 is configured to change the MG speed reduction ratio between two values (i.e., “Hi” and “Lo”). However, the MG speed change mechanism M2 may be configured to change the MG speed reduction ratio among three or more values. In the above-mentioned embodiment, the MG speed reduction ratio is changed during the selection operation. However, the embodiment may be modified such that the MG speed reduction ratio is changed during the shift operation.
In the above-mentioned embodiment, the boundary between the “Hi region” and the “Lo region” is located between the “1-2 selection position” and the “N position.” However, the boundary between the “Hi region” and the “Lo region” may be located between the “5-6 selection position” and the “N” position. In this case, the MG speed reduction ratio is set to “Lo” when any one of “1-st” through “4-th” is selected, and is set to “Hi” when “5-th” or “6-th” is selected.
In the above-mentioned embodiment, the fork shaft FSm (i.e., the sleeve Sm) is driven by using the movement of the second inner lever IL2 of the S&S shaft. However, as shown in
In this case, as shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-043803 | Mar 2011 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2012/055128 | 2/29/2012 | WO | 00 | 8/30/2013 |
