JP4778208B2 - Automatic transmission - Google Patents

Description

  The present invention relates to an automatic transmission, and more particularly to an automatic transmission in which a shift operation of a transmission in which a sub-transmission is combined with a main transmission is electrically shifted by an electric signal.

2. Description of the Related Art Conventionally, an automatic transmission has been proposed in which a mechanical clutch and a synchronous mesh gear type transmission are electronically controlled to automatically shift to a traveling speed corresponding to a traveling state (see Patent Document 1). In the automatic transmission, the fluid clutch (torque converter) is not interposed in the driving force transmission system from the engine to the driving wheels, so that the driving force transmission efficiency is high and the fuel consumption can be improved. In addition, drivability can be improved because there is no slip feeling unique to the fluid clutch.
Japanese Utility Model Publication No. 2004-125003

The automatic transmission described above is often provided with a sub-transmission in order to increase the number of gear stages, and the automatic transmission with the sub-transmission has a high vehicle speed when shifting from a high vehicle speed running state to a stopped state. Control is performed to switch from the gear ratio of the sub-transmission corresponding to traveling to the low-speed gear ratio of the sub-transmission corresponding to start-up (this control is referred to as range pre-low control). This switching condition is switched when the vehicle speed becomes a predetermined speed or less. For this reason, if the vehicle speed sensor that detects the vehicle speed outputs an abnormal signal such as a failure or a signal mixed with noise, the vehicle speed is judged to be low even though the vehicle speed is actually in a high vehicle speed state. There is a risk of switching the gear ratio of the machine to a gear ratio corresponding to a low vehicle speed. If the gear ratio is changed to correspond to the low speed, the rotation speed of the sub-transmission becomes over-rotation, which may reduce the durability of the sub-transmission.

  Therefore, an object of the present invention is to provide an automatic transmission that appropriately performs range pre-low control regardless of the detection state of a vehicle speed sensor.

A main transmission comprising a plurality of gear trains installed on the same axis and a gear train having a gear ratio of at least the high speed side and the low speed side are provided, and the rotational speed set by the main transmission is selectively high speed And a control means for selectively engaging a gear train of the sub-transmission with a first output shaft connected to the drive wheel according to an operating state. A main transmission gear position detecting means for detecting that the main transmission is neutral; and a sub-transmission gear for detecting a gear train of the auxiliary transmission engaged with the first output shaft by the control means. Position detection means, sub-transmission gear rotation speed detection means for detecting the rotation speed of the rotation shaft of the sub-transmission whose rotation speed changes according to the vehicle speed, and vehicle speed for detecting the speed of the vehicle equipped with the transmission Detecting means, and the control means includes the main transmission. Neutral, and the gear ratio of the auxiliary transmission is a case where the gear ratio of the high-speed side, only when the detected vehicle speed is lower than a predetermined value, and the rotational speed of the rotary shaft is lower than the predetermined value The automatic transmission is characterized in that the gear ratio of the auxiliary transmission is switched from a high-speed gear ratio to a low-speed gear ratio.

  According to a second invention, in the first invention, the sub-transmission includes a first gear coupled to the second output shaft of the main transmission, a first counter gear meshing with the first gear, 1 counter gear, a second counter gear connected via a counter shaft as the rotating shaft installed in parallel with the second output shaft, a second gear meshing with the second counter gear, and the second A gear is freely arranged and is connected to the drive wheel. The first output shaft is installed on the first output shaft, and the first output shaft is selectively connected to the first gear or the second gear. And a synchronous meshing means to be connected, wherein the auxiliary transmission gear rotational speed detecting means detects the rotational speed of the second gear or the counter shaft.

  According to a third invention, in the second invention, the number of teeth of the first gear is smaller than the number of teeth of the second gear.

  According to a fourth aspect, in the second aspect, the rotational speed of the counter shaft can be converted from the rotational speed of the second gear.

  Therefore, in the present invention, the main transmission is neutral and the engagement gear of the sub-transmission has a high-speed gear ratio, the detected vehicle speed is lower than a predetermined value, and the rotation speed of the counter shaft is When the gear ratio is lower than the predetermined value, the gear ratio of the sub-transmission is switched from the high-speed gear ratio to the low-speed gear ratio. Therefore, the vehicle speed detection means for detecting the vehicle speed fails or there is noise in the output signal. Even in such a case, the range pre-row control can be reliably determined.

  In FIG. 1, 1 is an engine, 2 is a friction clutch, 3 is a synchronous mesh automatic transmission, and an output shaft of the automatic transmission 3 is connected to a rear axle via a propeller shaft (not shown). The engine 1 is provided with an electronic governor device 1A that controls the injection amount of fuel supplied to the engine, and is installed between the engine 1 and the automatic transmission 3, and a clutch 2 that controls transmission of these powers. Is provided with a clutch booster 2A for performing the connection / disconnection operation. Further, the automatic transmission 3 is provided with a gear shift unit 3A for performing a shift to the target gear stage.

  As will be described later, the automatic transmission 3 further includes a main transmission gear train 40A as a main transmission and a splitter gear train 40B and a range gear train 40C as auxiliary transmissions. The gear train is selected so as to be a combination of gear trains to be the target shift speed. Reference numeral 27 denotes a supply / discharge valve that controls the operating pressure (compressed air) of the actuators constituting the clutch booster 2A and the gear shift unit 3A.

  As means for detecting driving information necessary for vehicle shift control, an engine rotation sensor 29 that detects the engine speed, an accelerator opening sensor 28 that detects the amount of depression of the accelerator pedal 7 (accelerator opening), and the clutch 2 A clutch stroke sensor 22 for detecting the stroke amount, gear position sensors 60, 62, 64 for detecting selected gear positions of the main transmission gear train 40A, splitter gear train 40B and range gear train 40C of the automatic transmission 3, The vehicle speed sensor 21 that detects the rotational speed of the output shaft 50 and the rotational speed of the gear of the main transmission gear train 40A that idles on the main shaft 46 (the first speed gear Zm1 in the embodiment) (= the rotational speed of the counter shaft 48) A main gear rotation sensor 23 is provided for detecting.

  Furthermore, in order to switch between automatic shift control of the clutch 2 and manual shift control based on the manual operation of the driver, clutch switches 24 and 25 for detecting an initial position (release state) and an operation position (depression state) of the clutch pedal are provided. A shift lever unit 4 is provided in the driver's seat as a shift operation means of the automatic transmission 3, and outputs a shift instruction signal (including a neutral instruction signal) corresponding to the shift position of the shift lever 4A. Further, a mode changeover switch 5 for selecting a manual shift mode in which the vehicle is shifted according to the driver's shift instruction and an automatic shift mode in which the shift is automatically controlled according to the driving state of the vehicle. Provided on the knob of the shift lever 4A. In the driver's seat, a brake pedal switch 26 for detecting depression of a brake pedal (not shown), a display unit (monitor) 13 for displaying the current gear position of the automatic transmission 3, and automatic downshift control are provided. A downshift interlocking switch 31 for selection and a buzzer 13A for alarming automatic downshift control are provided.

  A transmission control unit (TCU) 11 that outputs a control signal to the gear shift unit 3A to control a shift is installed, and is connected to an engine control unit (ECU) 12 that controls the operation of the engine by serial communication (LAN). In the TCU 11, when the mode changeover switch 5 selects the manual shift mode, when the shift instruction signal of the shift lever unit 4 does not match the shift position based on the gear position switch of the transmission 3, the target position corresponding to the shift instruction signal is reached. Shift request (shift command) is generated. When the mode change switch selects the automatic shift mode, the target stage is obtained based on a preset shift map from the driving state detection signals such as the detection signal of the accelerator opening sensor 28 and the detection signal of the vehicle speed sensor 21, and this target speed is obtained. When the gear does not coincide with the shift position based on the gear position switch of the transmission 3, a shift request (shift command) to the target gear is generated.

  When a shift request based on the shift instruction signal of the shift lever unit 4 is generated, the TCU 11 and ECU 12 control the electronic governor device 1A, the clutch booster 2A, and the gear shift unit 3A to perform a shift operation to the required position. . That is, after the clutch 2 is disengaged, the gear is released when the automatic transmission 3 is not neutral. Thereafter, when the clutch 2 is connected and the engine rotation speed is controlled, when the gear rotation speed of the main transmission gear train 40A enters the synchronization region, the automatic transmission 3 is geared.

  As shown in FIG. 2, the automatic transmission 3 has a configuration in which a splitter gear train 40B and a range gear train 40C as sub-transmissions are connected to the input side and the output side of the main transmission gear train 40A, respectively. Hereinafter, the configuration of the automatic transmission 3 will be described.

  A splitter gear Zm5 for switching the splitter gear train 40B to a high speed stage is freely arranged on the input shaft 42 for inputting the output of the engine 1, and a synchronizer hub 44A constituting the synchromesh mechanism 44 is provided at the tip thereof. Fixed. A main shaft (second output shaft) 46 disposed coaxially with the input shaft 42 includes a drive gear Zm4, a third speed gear Zm3, a second speed gear Zm2, and a first speed that constitute each gear stage of the main transmission gear train 40A. A gear Zm1 and a reverse gear ZmR are arranged freely to rotate, respectively, and a range high gear (first gear) Zr1 for switching the range gear train 40C to a high speed stage is fixed to the tip portion thereof. The main shaft 46 between the drive gear Zm4 and the third speed gear Zm3, the second speed gear Zm2 and the first speed gear Zm1, and the first speed gear Zm1 and the reverse gear ZmR has a synchronizer hub 44A constituting the synchromesh mechanism 44, respectively. Is fixed.

  On the other hand, the main counter shaft 48 arranged in parallel with the input shaft 42 and the main shaft 46 has a counter gear which is always meshed with the splitter gear Zm5, the drive gear Zm4, the third speed gear Zm3, the second speed gear Zm2 and the first speed gear Zm1. Splitter gear Zc5, counter drive gear Zc4, counter third speed gear Zc3, counter second speed gear Zc2 and counter first speed gear Zc1 are fixed. A counter reverse gear ZcR that is always meshed with the reverse gear ZmR is fixed to the main counter shaft 48 via a reverse idler gear ZmR1.

  A range low gear (second gear) Zr2 for switching the range gear train 40C to a low speed stage freely rotates on an output shaft (first output shaft) 50 that is arranged coaxially with the main shaft 46 and is connected to a propeller shaft (not shown). The synchronizer hub 44A constituting the synchromesh mechanism 44 is fixed to one end portion of the synchronizer hub 44A. A range counter high gear (first counter gear) Zcr1 and a range counter low gear (which are always meshed with the range high gear Zr1 and the range low gear Zr2) are connected to the range counter shaft (rotary axis = counter axis) 52 arranged in parallel with the output shaft 50. Second counter gear) Zcr2 is fixed.

  In the automatic transmission 3 having such a configuration, the main transmission gear train 40A and the range gear train 40C constitute six shift stages, and each of these shift stages is shifted half a stage by the splitter gear train 40B, so that the forward 12 stages and the reverse 2 stages. A gear stage is configured.

  Further, the gear shift unit 3A of the automatic transmission 3 pneumatically controls the gears of the main transmission gear train 40A, the splitter gear train 40B, and the range gear train 40C via the supply / discharge valve 27 controlled to be opened and closed by the TCU 11 incorporating the microcomputer. It consists of a main actuator to be switched, a splitter actuator, and a range actuator. The automatic transmission 3 detects gears of the main transmission gear train 40A, the splitter gear train 40B, and the range gear train 40C, specifically, gears connected to the shafts 42, 46, 50 by the synchromesh mechanism 44. A main position sensor 60, a splitter position sensor 62, and a range position sensor 64 are attached. Further, the automatic transmission 3 includes a vehicle speed sensor (vehicle speed detection means) 21 that detects the vehicle speed from the rotation speed of the output shaft (= propeller shaft) 50, and a main rotation speed sensor 23 that detects the rotation speed of the main counter shaft 48. A range rotation speed sensor 17 for detecting the rotation speed of the range counter shaft 52 is attached.

  The automatic transmission 3 to which the present invention is applied is configured as described above. Next, the configuration of the TCU 11 that performs the range pre-low control of the present invention will be described using the block diagram shown in FIG.

  The operating state of the automatic transmission 3 is input to the TCU 11 from each sensor. Specifically, the gear position fixed to the main shaft 46 of the main transmission gear train 40A is input from the position sensor 60, and the gear position fixed to the range counter shaft 52 of the range gear train 40C is input from the position sensor 64. . The rotational speed of the range counter shaft 52 is input from the range rotational speed sensor 17, the shift position is input from the shift lever unit 4, and the vehicle speed is input from the vehicle speed sensor 21.

  Based on each input signal, the TCU 11 controls switching of the range gear train 40C from fixed range high gear Zr1 to fixed range low gear Zr2 and connection / disconnection of the clutch 2.

  FIG. 4 shows that when the main transmission gear 40A is in a neutral state and the vehicle speed decreases from a high vehicle speed to a predetermined vehicle speed or less, the gear fixed to the output shaft 50 is switched to the range high gear Zr1 or the range low gear Zr2. It is a flowchart explaining pre-roll control. The neutral state may be selected based on an automatic transmission mode of an automatic transmission or a manual transmission mode selected by a driver.

  First, in step S1, the vehicle speed is input from the vehicle speed sensor 21. In step S2, the rotational speed of the gear of the range gear train 40C is input from the range rotational speed sensor 17, and in step S3, the gear position of the range gear train 40C fixed to the range counter shaft 52 is input from the position sensor 64. Further, in step S4 and step S5, the gear position of the main transmission gear train 40A fixed to the main shaft 46 is input from the position sensor 60, and the shift position is input from the shift lever unit 4.

  In step S6, it is determined whether or not the detected gear position of the main transmission gear train 40A is neutral. If it is neutral, the process proceeds to step S7, and otherwise, the process returns to step S1. In step S7, it is determined from the shift position input in step S5 whether or not the driver is operating the shift lever. If the shift lever 4A is not operated, the process proceeds to step S8. Returning to step S1, the control is repeated.

  In the following step S8, it is determined whether or not the gear position of the range gear train 40C is the range high gear Zr1, and if it is the range high gear Zr1, the process proceeds to step S9, otherwise the process returns to step S1.

  In step S9, the detected rotational speed of the range high gear Zr1 of the range gear train 40C is converted into a rotational speed X of the range counter shaft 52. Next, in step S10, it is determined whether or not the vehicle speed detected from the vehicle speed sensor 21 in step S1 is equal to or less than a predetermined value. If it is equal to or less than the predetermined value, the process proceeds to step S11, and if it exceeds the predetermined value, the process proceeds to step S12. The range pre-low control for switching from the range high gear Zr1 to the range low gear Zr2 in the range gear train 40C is not performed.

  In step S11, it is determined whether or not the rotational speed X calculated in step S9 is equal to or less than a predetermined value. If it is equal to or less than the predetermined value, the process proceeds to step S13, range pre-low control is performed, and the gear ratio of the sub-transmission is changed. Switch from high speed to low speed. If it exceeds the predetermined value, the process proceeds to step S12. After proceeding to step S12, the process proceeds to step S1. The rotational speed X of the range counter shaft may be directly detected using a sensor.

  As described above, in the present invention, in addition to the vehicle speed reaching a predetermined value or less as the execution determination condition for the range pre-roll control, both conditions that the rotational speed of the range counter shaft 52 becomes a predetermined value or less are satisfied. Therefore, even when the vehicle speed sensor 21 for detecting the vehicle speed is broken or noise is mixed in the output signal, the determination of the range pre-low control can be performed reliably. That is, when the vehicle is actually traveling at a high vehicle speed, the TCU 11 performs the range pre-low control based on the output of the inappropriate vehicle speed sensor 21, and the range counter shaft 52 may be over-rotated. In the present invention, as described above, the range pre-shaft control is determined based on the rotational speed of the range counter shaft, so that the range counter shaft 52 can be prevented from over-rotating.

  In an automatic transmission equipped with a sub-transmission, range pre-load control can be more reliably performed, which is useful for vehicles, particularly cargo vehicles.

It is a whole lineblock diagram showing an embodiment of this invention. It is a block diagram of an automatic transmission. It is a block diagram explaining the structure of TCU of this invention. It is a flowchart explaining the range pre-roll control of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 1A Electronic governor apparatus 2 Clutch 2A Clutch booster 3 Transmission 3A Gear shift unit 4 Shift lever unit 4A Shift lever 11 Transmission control unit 12 Engine control unit 13 Display unit 13A Buzzer 17 Range gear rotation sensor 21 Vehicle speed sensor 22 Clutch stroke sensor 23 Gear Rotation sensors 24, 25 Clutch switch 26 Brake pedal switch 28 Accelerator opening sensor 29 Engine rotation sensor 32 Range countershaft 40A Main transmission 40B Splitter 40C Range (sub transmission)
42 Input shaft 44 Synchromesh mechanism 44A Synchronizer hub 46 Main shaft 48 Main counter shaft 50 Output shaft 60 Main position sensor 62 Splitter position sensor 64 Range position sensor

Claims (4)

A main transmission composed of a plurality of gear trains installed on the same axis;
A sub-transmission for providing a gear train having a gear ratio of at least a high speed side and a low speed side, and selectively shifting the rotational speed set by the main transmission at a gear ratio of the high speed side and the low speed side;
Control means for selectively engaging a gear train of the sub-transmission according to a driving state with a first output shaft connected to drive wheels;
Main transmission gear position detecting means for detecting that the main transmission is neutral;
Sub-transmission gear position detecting means for detecting a gear train of the sub-transmission engaged with the first output shaft by the control means;
Sub-transmission gear rotation speed detection means for detecting the rotation speed of the rotation shaft of the sub-transmission whose rotation speed changes according to the vehicle speed;
Vehicle speed detection means for detecting the speed of a vehicle equipped with the transmission,
The control means is a case where the main transmission is neutral and the gear ratio of the sub-transmission is a high-speed gear ratio, the detected vehicle speed is lower than a predetermined value, and the rotation shaft rotates. The automatic transmission apparatus, wherein the gear ratio of the auxiliary transmission is switched from the high-speed gear ratio to the low-speed gear ratio only when the speed is lower than the predetermined value. The auxiliary transmission is
A first gear coupled to a second output shaft of the main transmission;
A first counter gear meshing with the first gear;
A first counter gear and a second counter gear connected via a counter shaft as the rotating shaft installed in parallel with the second output shaft;
A second gear meshing with the second counter gear;
The first output shaft, wherein the second gear is freely arranged and connected to a drive wheel;
Synchronous engagement means installed on the first output shaft and selectively connecting the first output shaft and the first gear or the second gear;
2. The automatic transmission according to claim 1, wherein the sub-transmission gear rotation speed detection unit detects a rotation speed of the second gear or the counter shaft.   The automatic transmission according to claim 2, wherein the number of teeth of the first gear is smaller than the number of teeth of the second gear.   The automatic transmission according to claim 2, wherein the rotation speed of the counter shaft can be converted from the rotation speed of the second gear.

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