Abstract:
A clutchless transmission apparatus and control method thereof. The transmission apparatus comprises a motor ( 10 ) and a transmission ( 20 ), said motor ( 10 ) is connected to said transmission ( 20 ) and supplies power to said transmission ( 20 ) via an input shaft of the transmission ( 20 ), wherein said apparatus further comprises a control device ( 30 ), which is electrically connected to said motor ( 10 ) and said transmission ( 20 ), wherein said control device ( 30 ) is configured to determine whether a gear-position shifting is required based on rotation speed of said transmission ( 20 ), if a gear-position shifting is required, regulates torque of said motor ( 10 ) to control said transmission ( 20 ) to disengage, and then regulates the rotation speed of said motor ( 10 ) based on the rotation speed of said transmission ( 20 ) to control said transmission ( 20 ) to engage for shifting gear-position. The clutchless transmission apparatus provided in the present invention doesn&#39;t need a clutch during gear-position shifting, and therefore it is light, simple, easy to maintain and control, and can be used in a wide range of application.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a national phase application of PCT Application No. PCT/CN2008/070752, filed Apr. 18, 2008, which claims priority from Chinese Patent Application No. 2007-10098247.1, filed Apr. 20, 2007, both contents of which are incorporated herein by reference in their entirety. 
     FIELD OF INVENTION 
     The present invention relates to a transmission apparatus for controlling gear-position shifting and a control method thereof, particularly to a clutchless transmission apparatus for controlling gear-position shifting speed and a control method thereof. 
     BACKGROUND 
     In a conventional internal combustion engine automobile, the functions of a clutch are: making the automobile starts stably; interrupting the power supply to the transmission apparatus to assist gear-position shifting; and preventing from overloading on the transmission apparatus. However, the implement for above functions with clutch not only requires the driver to operate skillfully but also causes power interruption inevitably; as a result, the acceleration/deceleration of the automobile is not smooth enough. In addition, the clutch operates by utilizing the friction on contact surfaces between drive part and driven part, utilizing liquid as driving medium or utilizing magnetic force for driving; therefore, the clutch has aging and wearing problems. Furthermore, in a hybrid automobile or electric automobile, since the motor can start the automobile with loads, the startup procedure doesn&#39;t need a clutch used in traditional internal combustion engine automobiles. Therefore, when designing a transmission apparatus for hybrid automobile or electric automobile, it is desired that to design a clutchless transmission apparatus and a control method to adapt for the intrinsic characteristics of motor, rather than to improve traditional transmission apparatuses in prior arts, such as the gear-position shifting control method used in a clutchless variable speed operated parallel hybrid automobiles as disclosed in CN1272203C. 
     SUMMARY OF INVENTION 
     In order to overcome the drawbacks of the above traditional control method thereof in operability, power performance, and component durability, the present invention provides a clutchless transmission apparatus for controlling gear-position shifting and the control method thereof, which is operated easily, delivers good power performance, and is essentially free of component durability problem. 
     The clutchless transmission apparatus for controlling gear-position shifting provided in the present invention comprises a motor and a transmission; said motor is connected to said transmission and supplies power to said transmission  20  via an input shaft of the transmission; wherein, said apparatus further comprises a control device, which is electrically connected to said motor and said transmission and is configured to determine whether a gear-position shifting is required based on rotation speed of said transmission; if a gear-position shifting is required, regulate torque of said motor firstly, to control said transmission to disengage, and then regulate rotation speed of said motor based on the rotation speed of said transmission to control said transmission to engage for shifting gear-position. 
     The present invention also provides a control method for shifting gear-position comprising: determining whether a gear-position shifting is required based on rotation speed of said transmission; if a gear-position shifting is required, regulating torque of said motor firstly, to control said transmission to disengage, and then regulating rotation speed of said motor based on the rotation speed of said transmission to control said transmission to engage for shifting gear-position. 
     The clutchless transmission apparatus provided in the present invention doesn&#39;t need clutch during gear-position shifting; instead of this, it controls gear-position shifting of the transmission based on the rotation speed detected and then controls the torque and rotation speed of the motor to adapt for gear-position shifting of the transmission. The transmission apparatus has advantages such as light weight, easy maintenance, simple structure, easy control, and wide range of application. 
    
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         FIG. 1  is a structural diagram of the clutchless transmission apparatus provided in the present invention; 
         FIG. 2  is a structural diagram of the control device used in the clutchless transmission apparatus provided in the present invention; 
         FIG. 3  is a flow diagram of the control method for shifting gear-position provided in the present invention; and 
         FIG. 4  is a schematic flow diagram of gear-up with the control method provided in the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereafter the present invention will be described in detailed with the accompanying drawings. 
     As shown in  FIG. 1 , the transmission apparatus provided in the present invention comprises a motor  10  and a transmission  20 . 
     The structure and working principle of the motor  10  is well known by those skilled in the art; said motor  10  can be any motor that is known by those skilled in the art, and therefore will not be described in details here. 
     The structure of the transmission  20  is also well known by those skilled in the art; for example, said transmission  20  can be a double-shaft transmission or three-shaft transmission. Here, the case of two-shaft transmission is discussed, which mainly comprises an input shaft, an output shaft, several sets of gears, and a gear-position shifting actuator. Since the motor  10  can be controlled to rotate in reverse direction easily, the transmission  20  described in the present invention is preferably a transmission without reverse gear-position. 
     Said motor  10  is connected to said transmission  20  and supplies power to said transmission  20  via the input shaft of said transmission  20 . No clutch is required between said motor  10  and said transmission  20 , and said motor  10  can be connected to said transmission  20  in any manner well known by those skilled in the art, for example, via a shaft-coupling or a spline. Wherein, said transmission apparatus further comprises a control device  30 , which is electrically connected to said motor  10  and said transmission  20 ; wherein, said control device  30  determines whether a gear-position shifting is required based on rotation speed of said transmission  20 ; if a gear-position shifting is required, said control device  30  will regulate torque of said motor  10  to control said transmission  20  to disengage, and then regulate the rotation speed of said motor  10  based on the rotation speed of said transmission  20  to control said transmission  20  to engage. 
     As shown in  FIG. 2 , said control device  30  comprises a signal collecting unit  31  and a signal processing unit  32  that are electrically connected to each other, a motor control unit  33  and a transmission control unit  34  that are electrically connected to said signal processing unit  32  respectively. Wherein, said signal collecting unit  31  is configured to collect rotation speed of said transmission  20 ; said signal processing unit  32  is configured to receive the rotation speed of transmission  20  collected by said signal collecting unit  31  and determine whether a gear-position shifting is required at the rotation speed, and if a gear-position shifting is required, send instructions for regulating torque or rotation speed of said motor  10  to said motor control unit  33 ; when the regulation of torque or rotation speed of said motor  10  is completed, said signal processing unit  32  sends instructions for controlling said transmission  20  to disengage or engage to said transmission control unit  34 ; said motor control unit  33  is configured to receive the instruction for regulating torque or rotation speed of said motor from said signal processing unit  32  and regulate the torque or the rotation speed of said motor  10  under the received instruction; said transmission control unit  34  is configured to receive the instructions for disengaging or engaging said transmission  20  from said signal processing unit  32  and control said transmission  20  to disengage or engage under the received instructions. 
     Said signal processing unit  32  stores a plurality of rotation speed thresholds S i  corresponding to each gear position, a plurality of torques M i  of the motor  10  under zero load at each rotation speed threshold S i , and a plurality of transmission ratios K i  corresponding to each gear position. The corresponding relation between torque M i  and rotation speed S i  is: M i  is in direct proportion to dS/dt, and the proportion factor is a constant for a given motor. The rotation speed thresholds S i , torques M i  and transmission ratios K i  can be stored in a memory. 
     Said control device  30  further comprises: said signal collecting unit  31 , configured to collect the current rotation speed S of transmission  20  in real time; said signal processing unit  32 , configured to receive said current rotation speed S, compare said current rotation speed S with the stored rotation speed thresholds S i  one by one to determine whether a gear-position shifting is required at the current rotation speed S, read out the torque M and transmission ratio K corresponding to the current rotation speed S, and choose a target gear position according to the current gear position with reference to or not with reference to the changing trend of current rotation speed S, and send instructions for regulating torque or rotation speed of the motor  10  to the motor control unit  33  and instructions for disengaging or engaging the transmission  20  to the transmission control unit  34 ; said motor control unit  33 , configured to receive the instruction for regulating torque or rotation speed from the signal processing unit  32  and regulate the torque of motor to M and the rotation speed of motor to S/K; and said transmission control unit  34 , configured to receive the instruction for disengaging or engaging from the signal processing unit  32  and instruct the transmission  20  to disengage or engage synchronizer with gear. In details, when the torque of motor  10  is regulated to M, the interaction force between the synchronizer and the gear in the transmission  20  at the current gear position is approximately zero, and therefore it is easy to disengage them without injury to the mechanical parts; at that moment, the signal processing unit  32  instructs the transmission  20  to disengage. While, when the rotation speed of the motor  10  is regulated to S/K, the rotation speed difference between the synchronizer and the gear in the transmission  20  at the target gear position is approximately zero, and therefore it is easy to engage them without injury to the mechanical parts; at that moment, the signal processing unit  32  instructs the transmission  20  to shift to the target gear position. 
     According to a preferred embodiment, the components in said control device  30  are further configured as follows: said signal processing unit  32  is configured to send the instruction for regulating motor torque to said motor control unit  33  firstly, and choose said target gear position according to the current gear position with reference to or not with reference to the changing trend of the current rotation speed S; said motor control unit  33  is configured to receive the instruction for regulating motor torque from said signal processing unit  32 , regulate the torque of said motor  10  to M, and send a feedback signal indicating the torque synchronization is completed to said signal processing unit  32 ; said signal processing unit  32  is configured to receive the feedback signal indicating the torque synchronization is completed from said motor control unit  33 , and send the instruction for disengaging to said transmission control unit  34 ; said transmission control unit  34  is configured to receive the instruction for disengaging from said signal processing unit  32 , instruct said transmission  20  to disengage, and send a feedback signal indicating the disengagement is completed to said signal processing unit  32 ; said signal processing unit  32  is configured to receive the feedback signal indicating the disengagement is completed from said transmission control unit  34 , receive the updated rotation speed S′ of said transmission  20 , and send the instruction for regulating rotation speed of the motor  10  to said motor control unit  33 ; said motor control unit  33  is configured to receive the instruction for regulating rotation speed of the motor  10  from said signal processing unit  32 , regulate the rotation speed of said motor  10  to S′/K, and send a feedback signal indicating the rotation speed synchronization is completed to said signal processing unit  32 ; said signal processing unit  32  is configured to receive the feedback signal indicating the rotation speed synchronization is completed from said motor control unit  33 , and send the instruction for engaging to said transmission control unit  34  for gear-position shifting; and said transmission control unit  34  is configured to receive the instruction for engaging from said signal processing unit  32 , and instructs said transmission  20  to engage for shifting to the target gear position. 
     In the apparatus provided in the present invention, said disengagement and engagement operations are implemented by gear-position shifting actuator of said transmission  20  under the instruction from said transmission control unit  34  by means of electric signals. Said gear-position shifting actuator is configured to implement disengagement by disengaging the gear in the current gear position from the input shaft and implement engagement by engaging the gear in the target gear position to the output shaft. The structure, connection means, and working principle of said gear-position shifting actuator are well known by those skilled in the art; for example, it can be implemented with any synchronizer, and the gear-position shifting actuator will not be described in details here. 
     In the apparatus provided in the present invention, said signal collecting unit  31  is a rotation speed sensor, which can be implemented as a photoelectric sensor, a Hall sensor, or a magnetic induction sensor, mounted on the output shaft of said transmission  20 , and configured to detect the rotation speed of said transmission  20 . 
     In the apparatus provided in the present invention, said rotation speed thresholds S, are set as follows: the number of said rotation speed thresholds S i  is N, and threshold S i =maximum rotation speed×i/N, where, 2≦N&lt;10, i is an integer, and 0&lt;i&lt;N. When above threshold setting method is used, in order to choose said target gear position, it is required to detect the changing trend of the rotation speed and determine whether to gear up or gear down in accordance with increase/decrease of the rotation speed. 
     Preferably, in order to reduce frequent gear-position shifting and simplify the judgment so as to choose the target gear position solely according to the current gear position, in the apparatus provided in the present invention, the number of said rotation speed thresholds S i  is 2N, and threshold S i =maximum rotation speed×i/N±Y, where 2≦N&lt;10, i is an integer and 0&lt;i&lt;N, and Y is much smaller than S, and is different for different thresholds S i . Specifically, there are two thresholds between every two gear positions, wherein, maximum rotation speed×i/N+Y is the threshold for shifting from a lower gear position to a higher gear position, while maximum rotation speed×i/N−Y is the threshold for shifting from a higher gear position to a lower gear position. Wherein, Y is an integer much smaller than S i , and can be set to a percentage of S i , e.g., 2-5%. However, if S i  is great, 5% of S i  will be too great against timely gear-position shifting; therefore Y can be set to different values depending on different thresholds S i . Preferably, if S i  is great, the ratio of Y/S i  can be decreased appropriately, e.g., to 2%. 
     In the apparatus provided in the present invention, said control device  30  can be implemented conveniently in the electronic control unit of the automobile, or it can be implemented by means of a DSP or embedded system. 
     The present invention also provides a control method for shifting gear position, comprising: determining whether a gear-position shifting is required based on rotation speed of said transmission  20 ; if so, regulating torque of said motor  10  firstly, to control said transmission  20  to disengage, and then regulating rotation speed of said motor  10  based on the rotation speed of said transmission  20  to control said transmission  20  to engage for gear-position shifting. 
     As shown in  FIG. 3 , the control method provided in the present invention comprises the following steps: collecting the rotation speed of said transmission  20 ; determining whether a gear-position shifting is required at that rotation speed; if so, regulating the torque and rotation speed of said motor  10 ; when the regulation of torque of said motor  10  is completed, disengaging said transmission  20 ; and when the regulation of rotation speed of said motor  10  is completed, engaging to gear position of said transmission  20 . 
     As shown in  FIG. 4 , the control method provided in the present invention further comprises the following steps: storing a plurality of rotation speed thresholds S i  corresponding to each gear position, a plurality of torques M i  of the motor  10  under zero load at each rotation speed threshold S i , and a plurality of transmission ratios K i  corresponding to each gear position; collecting the current rotation speed S of said transmission  20 ; comparing the current rotation speed S with the rotation speed thresholds S i  one by one to determine whether a gear-position shifting is required at the current rotation speed S; reading out the torque M and the transmission ratio K corresponding to the current rotation speed S, and choosing a target gear position according to the current gear position with reference to or not with reference to the changing trend of the current rotation speed S; regulating the torque of the motor  10  to M and the rotation speed of the motor to S/K; when the torque of the motor is regulated to M, instructing the transmission  20  to disengage; when the rotation speed of the motor is regulated to S/K, engaging to said target gear position. 
     The control method provided in the present invention further comprises the following steps: regulating the torque of the motor  10  to M; indicating the torque synchronization is completed; instructing the transmission  20  to disengage; indicating the disengagement is completed; collecting the updated rotation speed S′ of the transmission  20 ; regulating the rotation speed of said motor  10  to S′/K; indicating the rotation speed synchronization is completed; instructing the transmission  20  to engage to the target gear position. 
     In the control method, said rotation speed thresholds S i  are set as follows: the number of said rotation speed thresholds S, is N, and threshold S i =maximum rotation speed×i/N, where, 2≦N&lt;10, i is an integer, and 0&lt;i&lt;N. 
     Preferably, the number of said rotation speed thresholds S i  is 2N, and threshold S i =maximum rotation speed×i/N±Y, where, 2N&lt;10, i is an integer and 0&lt;i&lt;N, Y is an integer much smaller than S i  and can be different for different thresholds S i . 
     Hereafter the working principle and process of the present invention will be described in detail in the example of a two-speed transmission. 
     In the first threshold setting method, only one threshold is to be set, and S 1 =maximum rotation speed/2. The automobile starts and runs at a low speed, and when the rotation speed exceeds S 1 , the signal processing unit  32  sends an instruction to the motor control unit  33  firstly to regulate the motor torque; the motor control unit  33  receives the instruction for regulating motor torque from the signal processing unit  32  and regulates the motor torque to M; at that moment, the engaging resistance between the synchronizer and the gear of the transmission in the current gear position is minimum, and the motor control unit  33  sends a feedback signal to the signal processing unit  32  to indicate the torque synchronization is completed; the signal processing unit  32  receives the feedback signal indicating the torque synchronization is completed from the motor control unit  33 , and sends an instruction to the transmission control unit  34  to disengage; the transmission control unit  34  receives the instruction for disengagement from the signal processing unit  32 , and instructs the transmission to disengage; at that moment, the shifting fork shifts the synchronous gear ring into neutral position, and sends a feedback signal to the signal processing unit  32  to indicate the disengagement is completed; the signal processing unit  32  receives the feedback signal indicating the disengagement is completed from the transmission control unit  34 , receives the updated rotation speed S′ of the transmission, and sends an instruction to the motor control unit  33  to regulate the rotation speed of the motor  10 ; the motor control unit  33  receives the instruction for regulating motor speed from the signal processing unit  32 , regulates the rotation speed of the motor  10  to S′/K, and sends a feedback signal to the signal processing unit  33  to indicate the rotation speed synchronization is completed; the signal processing unit  32  receives the feedback signal indicating the rotation speed synchronization is completed from the motor control unit  33 , and sends a engaging instruction to the transmission control unit  34 ; the transmission control unit  34  receives the engaging instruction from the signal processing unit  32 , and instructs the transmission  20  to shift into the higher gear position. 
     When the automobile slows down to a rotation speed smaller than S 1 , gear-down is required; the operating procedures are similar to those for gear-up, and therefore will not be described here. 
     In the second threshold setting method, two thresholds have to be set, and S 1 =maximum rotation speed/2−Y and S 2 =maximum rotation speed/2+Y, where, Y=maximum rotation speed×5%. When the automobile speeds up to a rotation speed higher than S 2 , gear-up is required; whereas when the automobile slows down to a speed lower than S 1 , gear-down is required. The operating procedures are similar to those described above, and therefore will not be described here. 
     Since the motor  10  can be easily controlled to rotate in reverse direction by applying reverse voltage, it is unnecessary to arrange reverse gear and corresponding drive mechanism; when reversal is required, it is only need to control the motor  10  to rotate in reverse direction and increase the torque.