JP3706194B2 - Continuously variable transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a continuously variable transmission.
[0002]
[Prior art]
Conventionally, in a continuously variable transmission using a V-belt type continuously variable transmission (CVT), a V belt is stretched between a primary pulley and a secondary pulley. By changing the interval between the V-shaped grooves, the effective diameters of the primary pulley and the secondary pulley are changed, and the gear is changed at a continuously variable transmission ratio. In this case, the gear ratio is a value obtained by dividing the rotation speed of the primary pulley by the rotation speed of the secondary pulley.
[0003]
In the continuously variable transmission in which the continuously variable transmission mode and the stepped transmission mode can be selected, when the continuously variable transmission mode is selected, the target rotational speed of the primary pulley corresponding to the engine load is selected. Is set, and the gear ratio is changed so that the target rotational speed is achieved. Further, when the stepped transmission mode is selected, a plurality of preset gear ratios are sequentially selected by the driver operating a shift lever or the like.
[0004]
Furthermore, when shifting from the continuously variable transmission mode to the stepped transmission mode, the gear ratio when the continuously variable transmission mode is selected is temporarily fixed, and the driver operates the shift lever or the like. When the upshift is performed, the gear ratio of the upper gear is selected, and when the downshift is performed, the gear ratio of the lower gear is selected.
[0005]
If the difference between the fixed gear ratio and the gear ratio of the first gear is small and falls within a predetermined range, the gear ratio of the first gear is selected and similarly fixed. When the difference between the set gear ratio and the gear ratio of the next lower gear is small and falls within a predetermined range, the gear ratio of the next lower gear is selected.
[0006]
[Problems to be solved by the invention]
However, in the conventional continuously variable transmission, when the gear ratio of the upper gear stage or the gear ratio of the lower gear stage is selected, the fixed gear ratio and the selected gear ratio are Since the difference is not sufficient, the driver may not be able to experience an upshift or downshift.
[0007]
Further, when the gear ratio of the gear stage that is one step higher or the gear ratio of the gear step that is one step lower is selected, the difference between the fixed gear ratio and the selected gear ratio becomes too large, and the gear shift shock Will occur.
In addition, the driver determines whether the difference between the fixed gear ratio and the gear ratio of the upper gear is small, or whether the difference between the fixed gear ratio and the gear ratio of the lower gear is small. Since it is not known whether the gear ratio of the upper gear or the gear of the lower gear is selected, the gear ratio of the upper gear or the gear of the lower gear is selected. It cannot be predicted whether the transmission ratio will be selected.
[0008]
Furthermore, in the stepped speed change mode, one of a plurality of preset gear ratios is selected, so that the V belt always hits the same part of the primary pulley and the secondary pulley. Therefore, the primary pulley and the secondary pulley are locally worn, and the durability of the continuously variable transmission is reduced.
The present invention solves the problems of the above-described conventional continuously variable transmission, so that an upshift or a downshift can be experienced, a shift shock does not occur, and a selected gear ratio is expected. It is an object of the present invention to provide a continuously variable transmission that can be improved in durability.
[0009]
[Means for Solving the Problems]
For this purpose, in the continuously variable transmission according to the present invention, a continuously variable transmission that shifts at a continuously variable transmission ratio, an actuator that changes the transmission ratio of the continuously variable transmission, and a continuously variable transmission from the continuously variable transmission mode. A shift mode determining means for determining whether or not the mode has been changed, a reference speed ratio calculating means for calculating a speed ratio when the stepless speed change mode is changed to the stepped speed change mode, and the reference speed ratio calculation means. A shift ratio sequence calculating means for calculating a plurality of shift ratios suitable for upshifting and downshifting with reference to the changed gear ratio, and when shifting from the continuously variable transmission mode to the stepped transmission mode The speed ratio calculated by the reference speed ratio calculating means is fixed as a target speed ratio, and then the shift ratio of the upshift is determined from the plurality of speed ratios calculated by the speed ratio sequence calculating means. Has a target speed ratio determining means for determining a gear ratio of the target corresponding to the instruction for gear shift of the shows and the downshift, and an actuator operating means for operating said actuator so that the speed ratio of the target is achieved.
[0010]
In another continuously variable transmission according to the present invention, the gear ratio sequence calculating unit multiplies the gear ratio calculated by the reference gear ratio calculating unit by an upshift gear constant and a downshift gear constant. Thus, the plurality of gear ratios are calculated.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a functional block diagram of a continuously variable transmission according to an embodiment of the present invention.
In the figure, 12 is a continuously variable transmission that performs a speed change with a continuously variable transmission ratio, 43 is a hydraulic actuator that changes the speed ratio of the continuously variable transmission 12, and 205 is a stepped transmission mode detection signal that will be described later. This is a position sensor sent to the control unit 206.
[0012]
Then, the control unit 206 calculates whether or not the shift mode determining means 250 determines whether or not the stepless transmission mode has shifted to the stepped shift mode, and calculates the gear ratio when the stepless shift mode has shifted to the stepped shift mode. Reference speed ratio calculation means 251 and the speed ratio α calculated by the reference speed ratio calculation means 251_MMultiple gear ratios α suitable for upshift and downshift_iThe gear ratio sequence calculating means 252 for calculating the gear ratio α calculated by the reference speed ratio calculating means 251 when the stepless speed change mode is shifted to the stepped speed change mode._MIs fixed as the target gear ratio α, and then a plurality of gear ratios α calculated by the gear ratio sequence calculating means 252 are used._iTo the target gear ratio determining means 253 for determining the target gear ratio α corresponding to the upshift gearshift instruction and the downshift gearshift instruction, and the hydraulic actuator 43 so that the target gear ratio α is achieved. Actuator actuating means 254 for actuating.
[0013]
FIG. 2 is a schematic diagram of a continuously variable transmission according to an embodiment of the present invention.
In the figure, reference numeral 11 denotes a continuously variable transmission. The continuously variable transmission 11 includes a V-belt continuously variable transmission 12, a forward / reverse mode switching device 13, a torque converter 16, a counter shaft 17, and a differential device 19. Have.
The torque converter 16 is connected to the engine output shaft 20 via a front cover 27, and is rotated by a pump impeller 21 rotated by an engine (not shown), a turbine runner 23 connected to the input shaft 22, and a one-way clutch 25. A stator 26 supported by the case 10 and a lock-up clutch 15 disposed between the front cover 27 and the input shaft 22 are provided.
[0014]
In addition, 30 is a damper spring disposed between the lockup clutch plate 15a and the input shaft 22, and 31 is an oil pump that is connected to the pump impeller 21 and is driven by the rotation from the engine.
The continuously variable transmission 12 includes a primary sheave 36 and a secondary shaft 37 that include a fixed sheave 33 that is fixed to a primary shaft 32 and a movable sheave 35 that is slidably movable with respect to the primary shaft 32. A secondary pulley 41 comprising a fixed sheave 39 fixed to the secondary shaft 37 and a movable sheave 40 slidably disposed with respect to the secondary shaft 37, and is stretched between the primary pulley 36 and the secondary pulley 41. A metal V-belt 42 is provided.
[0015]
Further, a hydraulic actuator 43 having a double piston structure is disposed on the back surface of the movable sheave 35 of the primary pulley 36, and a hydraulic actuator 45 having a single piston structure is disposed on the back surface of the movable sheave 40 of the secondary pulley 41.
The hydraulic actuator 43 on the primary pulley 36 side includes a cylinder member 46 and a reaction force support member 47 fixed to the primary shaft 32, a cylindrical member 49 fixed to the movable sheave 35, and a piston member 50. A first hydraulic chamber 51 is formed by the cylindrical member 49, the reaction force support member 47 and the back surface of the movable sheave 35, and a second hydraulic chamber 52 is formed by the cylinder member 46 and the piston member 50.
[0016]
In this case, the first hydraulic chamber 51 and the second hydraulic chamber 52 are connected to each other by the communication hole 47a, and when receiving the same hydraulic pressure as the hydraulic actuator 45 on the secondary pulley 41 side, the axial hydraulic force is applied. Double.
On the other hand, the hydraulic actuator 45 on the secondary pulley 41 side includes a reaction force support member 53 fixed to the secondary shaft 37 and a cylindrical member 55 fixed to the back surface of the movable sheave 40, and the reaction force support member 53 and A hydraulic chamber 56 is formed by the cylindrical member 55. A preload spring 57 is disposed between the movable sheave 40 and the reaction force support member 53 to urge the movable sheave 40 toward the fixed sheave 39.
[0017]
The forward / reverse mode switching device 13 includes a double pinion planetary gear 60 for switching forward and backward, a reverse brake B₁, First clutch (D range clutch) C₁Second clutch (L range clutch) C₂And a one-way clutch F. And the first clutch C₁And the one-way clutch F are arranged in series, and the first clutch C is interposed between the input shaft 22 and the fixed sheave 33 of the primary pulley 36.₁And the one-way clutch F and the second clutch C₂Are arranged in parallel.
[0018]
In the planetary gear 60, the sun gear S is connected to the input shaft 22 and the first pinion P₁And second pinion P₂The carrier CR that supports the ring is fixed to the fixed sheave 33 of the primary pulley 36, and the ring gear R is the reverse brake B₁Respectively.
A large gear 61 and a small gear 62 are fixed to the counter shaft 17, and the large gear 61 and a gear 63 fixed to the secondary shaft 37 are engaged with each other. The gear 65 of the differential device 19 is meshed.
[0019]
The differential device 19 includes a differential case 76 to which the gear 65 is fixed, a differential gear 66 supported by the differential case 76, and left and right side gears 67 and 69, and the rotation transmitted to the differential case 76 via the gear 65. Is differentially transmitted by the differential gear 66 and the side gears 67 and 69 and transmitted to the left and right axles 70 and 71. Reference numeral 200 denotes an engine speed sensor, 201 denotes an input shaft speed sensor, and 202 denotes a vehicle speed sensor.
[0020]
Next, the hydraulic circuit of the continuously variable transmission 11 configured as described above will be described.
FIG. 3 is a hydraulic circuit diagram of the continuously variable transmission according to the embodiment of the present invention.
In the figure, 31 is an oil pump, 80 is an oil pump control valve, 81 is a solenoid valve for a control valve, 82 is a primary regulator valve, 83 is a secondary regulator valve, 85 is a linear solenoid valve for line pressure control, and 86 is for a solenoid valve. It is a modulator valve.
[0021]
Reference numeral 87 denotes a manual valve, and the hydraulic pressure of the line pressure port 1 is switched to the port 2 or 3 as shown in the table in FIG.
89 is a modulator valve, 90 is a C2 control valve, 91 is a duty control solenoid valve, and C1 is a first clutch C.₁(FIG. 2) hydraulic servo, C2 is the second clutch C₂Hydraulic servo, B1 is reverse brake B₁, 100 is an accumulator for the hydraulic servo B1, and 101 is an accumulator for the hydraulic servo C1.
[0022]
Further, 102 is a ratio control valve for controlling the transmission ratio, 103 is a linear solenoid valve for adjusting the control hydraulic pressure supplied to the ratio control valve 102, 43 is a hydraulic actuator on the primary pulley 36 side, and 45 is a secondary pulley. 41 is a hydraulic actuator on the 41 side.
Further, 16 is a torque converter, 105 is a lock-up control valve, 106 is a lock-up relay valve, 107 is a linear solenoid valve for lock-up control, and 109 is a cooler.
[0023]
Next, the control device of the continuously variable transmission 11 having the above configuration will be described.
FIG. 4 is a block diagram of a control device for a continuously variable transmission according to an embodiment of the present invention, and FIG. 5 is a schematic diagram of a speed selecting device according to an embodiment of the present invention.
In the figure, reference numeral 206 denotes a control unit (ECU) composed of an in-vehicle computer. The control unit 206 includes an engine speed sensor 200 for detecting the engine speed and the speed of the primary pulley 36 (FIG. 2), that is, an input shaft. An input shaft rotational speed sensor 201 that detects the rotational speed of the motor 22, a rotational speed of the secondary pulley 41, that is, a vehicle speed sensor 202 that detects the vehicle speed, an accelerator depression amount, that is, an accelerator sensor 203 that detects the throttle opening, 205 are connected to each other.
[0024]
In the present embodiment, the speed selecting device includes a shift lever 301 as shown in FIG. 5, and by operating the shift lever 301, each switch (not shown) constituting the position sensor 205 is turned on / off. It is like that. That is, the shift lever 301 is moved in the continuously variable transmission mode guide groove 302 to be placed at the parking range position P, the reverse travel range position R, the neutral range position N, the forward travel range position D, and the low range position L. When the shift lever 301 is placed at the forward travel range position D, the continuously variable transmission mode is set.
[0025]
Then, the shift lever 301 is moved to the stepped speed change mode guide groove 304 through the mode transition groove 303 and moved in the stepped speed change mode guide groove 304 to be placed at the upshift position + and the downshift position −. be able to. Further, the control unit 206 includes a pump solenoid 381 for controlling the control valve solenoid valve 81 (FIG. 3), a line pressure solenoid 385 for controlling the line pressure control linear solenoid valve 85, and a duty control solenoid. C for controlling solenoid valve 91₂A solenoid 391 for shifting, a shifting solenoid 403 for controlling the linear solenoid valve 103, and a lock-up solenoid 407 for controlling the linear solenoid valve 107 are respectively connected.
[0026]
Next, the operation of the continuously variable transmission 11 having the above configuration will be described.
First, when the rotation of an engine (not shown) is transmitted to the oil pump 31, a predetermined oil pressure is generated by the oil pump 31. Then, the control unit 206 sends a signal SG1 calculated based on the engine load to the line pressure solenoid 385 and causes the line pressure control linear solenoid valve 85 to generate a control oil pressure. When the control hydraulic pressure is sent to the primary regulator valve 82, the primary regulator valve 82 regulates the hydraulic pressure generated by the oil pump 31 to a line pressure.
[0027]
When the driver selects the forward travel range or low range in the continuously variable transmission mode and puts the shift lever 301 at the forward travel range position D or low range position L, the hydraulic pressure from the line pressure port 1 of the manual valve 87 is increased. The first clutch C is supplied to the hydraulic servo C1 through the port 2.₁Are engaged.
As a result, the rotation of the engine output shaft 20 is caused by the torque converter 16, the input shaft 22, the one-way clutch F, and the first clutch C.₁Is transmitted to the primary pulley 36, is shifted at a predetermined gear ratio in the continuously variable transmission 12, and is transmitted to the secondary pulley 41. The rotation of the secondary pulley 41 is transmitted to the left and right axles 70 and 71 via the countershaft 17 and the differential device 19. When the forward travel range is selected, the first clutch C is connected via the one-way clutch F.₁Since only the gear is engaged, the engine brake does not operate during coasting.
[0028]
When the low range is selected, the position sensor 205 detects that the shift lever 301 is placed at the low range position L, and the control unit 206 detects C₂A duty signal SG3 is sent to the solenoid 391. Then, the duty control solenoid valve 91 is controlled, the C2 control valve 90 is switched, and the hydraulic pressure is supplied to the hydraulic servo C2, and the second clutch C₂Are engaged. As a result, the engine brake can be operated during the coasting.
[0029]
When the driver selects the reverse travel range in the continuously variable transmission mode and places the shift lever 301 at the reverse travel range position R, the hydraulic pressure from the port 1 of the manual valve 87 is transferred to the hydraulic servo B1 via the port 3. Supplied with reverse brake B₁Are engaged.
At this time, the ring gear R of the planetary gear 60 is fixed, and the rotation input from the input shaft 22 to the sun gear S is output as rotation in the reverse direction from the carrier CR and transmitted to the primary pulley 36.
[0030]
Incidentally, in the continuously variable transmission 12, the line pressure from the primary regulator valve 82 is supplied to the hydraulic actuator 45 of the secondary pulley 41, and a belt clamping force corresponding to the load torque is generated by the hydraulic actuator 45. .
On the other hand, the linear solenoid valve 103 is controlled based on a shift signal SG4 sent from the control unit 206 to the shift solenoid 403, and a control hydraulic pressure is generated. The ratio control valve 102 is controlled by the control oil pressure, and the apply oil pressure controlled by the ratio control valve 102 is supplied to the hydraulic actuator 43. As a result, the gear ratio of the continuously variable transmission 12 is determined.
[0031]
In this case, for example, the control unit 206 calculates the best fuel consumption primary pulley rotation speed corresponding to the throttle opening detected by the accelerator sensor 203 based on the best fuel consumption power line capable of driving the engine with the best fuel consumption. Then, the best fuel efficiency primary pulley rotation speed is set as the target rotation speed.
Then, the actual input shaft rotational speed detected by the input shaft rotational speed sensor 201 is compared with the target rotational speed. When the actual input shaft rotational speed is higher than the target rotational speed, the apply hydraulic pressure is increased. As a result, the effective diameter of the primary pulley 36 is increased, the transmission ratio of the continuously variable transmission 12 is decreased, and an upshift is performed. Further, when the actual input shaft speed is lower than the target speed, the apply hydraulic pressure is lowered. As a result, the effective diameter of the primary pulley 36 is reduced, the transmission ratio of the continuously variable transmission 12 is increased, and a downshift is performed.
[0032]
When the forward travel range of the continuously variable transmission mode is selected and the stepped transmission mode is selected, the position sensor 205 detects that the shift lever 301 has been moved to the stepped transmission mode guide groove 304. Then, the stepped shift mode detection signal SG5 is sent to the control unit 206.
When the position change mode detection signal SG5 is sent from the position sensor 205, the speed change mode determination means 250 (FIG. 1) of the control unit 206 determines that the stepless speed change mode has shifted to the stepped speed change mode. The reference speed ratio calculating means 251 of the control unit 206 determines the speed ratio when the stepless speed change mode is changed to the stepped speed change mode as the reference speed ratio α._MCalculate as Here, the number of rotations of the input shaft 22 and the vehicle speed when shifting from the continuously variable transmission mode to the stepped transmission mode are set to N, respectively._I, N_OThen,
α_M= N_I/ N_O
become.
[0033]
Then, the control unit 206 sets the reference speed ratio α to the target speed ratio α._MTo set the gear ratio to α_MSecure to.
Next, the gear ratio sequence calculating means 252 of the control unit 206 has a reference gear ratio of α_MThe reference gear ratio α_MMultiple gear ratios α suitable for upshift and downshift_i(I = 1, 2,..., N) is calculated and the gear ratio α_iIs stored in a memory (not shown) built in the control unit 206.
[0034]
In this case, 1 / r (where r <1) is preset as the gear ratio constant for upshifting, and r is preset as the gear ratio constant for downshifting, and the reference gear ratio α_MIs repeatedly multiplied by the number of times corresponding to the gear position, so that the gear ratio α_iCan be calculated.
For example, the reference gear ratio α_MIn contrast, the upshift gear ratio α corresponding to each gear position_iUPBut
α_iUP= Α_M・ R, α_M・ R², ..., α_M・ R^{n / 2}
And the gear ratio α for downshift_iDOWNBut
α_iDOWN= Α_M/ R, α_M/ R², ..., α_M/ R^{n / 2}
As shown in FIG.
[0035]
Next, based on the shift operation detection signal SG6 sent from the position sensor 205, the controller 206 determines whether or not a shift is instructed in the stepped shift mode. It is determined whether or not a shift is instructed. In this case, when the shift lever 301 moved to the stepped transmission mode guide groove 304 is moved in the stepped transmission mode guide groove 304 and placed at the upshift position +, it is assumed that upshifting is instructed. If it is determined and placed in the downshift position −, it is determined that the downshift is instructed.
[0036]
When the driver puts the shift lever 301 at the upshift position +, the target gear ratio determination means 253 of the control unit 206 determines that the upper gear is selected, and the gear ratio α from the memory is determined._iUPThe value of α_MRead r, the value α_M• Set r to the target gear ratio α. When the driver puts the shift lever 301 at the downshift position −, the target gear ratio determining means 253 of the control unit 206 determines that the lower gear is selected, and the gear ratio α from the memory is determined._iDOWNThe value of α_M/ R is read and the value α_M/ R is set to the target gear ratio α.
[0037]
Subsequently, the control unit 206 controls the minimum speed ratio α so that the target speed ratio α does not lower the engine efficiency._MINLarger, maximum gear ratio α_MAXWhether it is smaller, ie
α_MIN<Α <α_MAX                                    ...... (1)
To determine whether the condition is satisfied. When the condition of the expression (1) is not satisfied, the control unit 206 does not allow the shift.
[0038]
In addition, the control unit 206 controls the engine speed N corresponding to the target speed ratio α._eAnd the engine speed N_eIs the minimum engine speed that causes engine stall._MINMaximum engine speed N that causes higher engine revolutions_MAXWhether lower, i.e.
N_MIN<N_e<N_MAX                                  (2)
To determine whether the condition is satisfied. When the condition of the expression (2) is not satisfied, the control unit 206 does not permit the shift.
[0039]
Then, the control unit 206 sets the target gear ratio α when the expressions (1) and (2) are satisfied.
Subsequently, the actuator actuating means 254 of the control unit 206 calculates the target rotational speed based on the target speed ratio α and the actual input shaft rotational speed detected by the input shaft rotational speed sensor 201, and the actual rotational speed is calculated. The input shaft rotational speed is compared with the target rotational speed, and when the actual input shaft rotational speed is higher than the target rotational speed, the apply hydraulic pressure is increased. As a result, the effective diameter of the primary pulley 36 is increased, the actual transmission ratio of the continuously variable transmission 12 is decreased, and an upshift can be performed.
[0040]
The control unit 206 lowers the apply hydraulic pressure when the actual input shaft speed is lower than the target speed. As a result, the effective diameter of the primary pulley 36 is reduced, the transmission ratio of the continuously variable transmission 12 is increased, and a downshift can be performed.
Thus, when the shift lever 301 is placed at the upshift position +, the gear ratio α_iUPValue of α_MWhen r is set to the target gear ratio α and an upshift is performed and the shift lever 301 is placed at the downshift position −, the gear ratio α_iDOWNValue of α_M/ R is set to the target gear ratio α, and a downshift is performed.
[0041]
Thereafter, when the shift lever 301 is again placed at the upshift position +, the gear ratio α of the gear stage that is one step higher._iUPValue of α_M・ R²Is set to the target gear ratio α and an upshift is performed, and when the shift lever 301 is placed at the downshift position − again, the gear ratio α of the gear stage that is one step lower is set._iDOWNValue of α_M/ R²Is set to the target gear ratio α, and a downshift is performed.
[0042]
In this case, in the stepped speed change mode, the speed ratio α of each adjacent speed change stage_iSince the difference between them becomes appropriate, the driver can always experience the upshift or downshift. Further, it is possible to prevent a shift shock from occurring. The driver then changes the gear ratio α when the upshift or downshift is performed._iCan be expected.
[0043]
Moreover, the gear ratio α_MIs multiplied by a shift constant r for upshift and a shift constant 1 / r for downshift._iIs calculated, the gear ratio α of each gear stage_iThe difference between them becomes constant.
Therefore, the shift feeling in the upshift and downshift is constant.
[0044]
Further, in the stepped transmission mode, the gear ratio α when the stepless transmission mode is changed to the stepped transmission mode._MMultiple gear ratios α_iIs calculated so that the gear ratio α_iAlways fluctuates.
Accordingly, since the V belt 42 does not always hit the same part of the primary pulley 36 and the secondary pulley 41, the primary pulley 36 and the secondary pulley 41 are not locally worn, and the durability of the continuously variable transmission 11 is improved. Can be improved.
[0045]
Next, a flowchart will be described.
FIG. 6 is a flowchart showing the operation of the continuously variable transmission according to the embodiment of the present invention. The flowchart is a subroutine when the stepless speed change mode is shifted to the stepped speed change mode, and a shift output process is performed in a main routine (not shown).
Step S1 The shift mode determining means 250 (FIG. 1) of the control unit 206 (FIG. 4) determines whether or not the stepless shift mode is shifted to the stepped shift mode. If the transition from the continuously variable transmission mode to the stepped transmission mode is made, the process proceeds to step S2, and if not, the process proceeds to step S5.
Step S2: The reference speed ratio calculating means 251 of the control unit 206 determines the speed ratio α when the stepless speed change mode is changed to the stepped speed change mode._MIs calculated.
Step S3: The control unit 206 sets the speed ratio α to the target speed ratio α._MTo set the gear ratio to α_MSecure to.
Step S4: The gear ratio calculation means 252 of the control unit 206 determines that the reference gear ratio is α._MThe reference gear ratio α_MMultiple gear ratios α suitable for upshift and downshift_iIs calculated.
Step S5 The control unit 206 determines whether or not a shift is instructed in the stepped shift mode based on the shift operation detection signal SG6 sent from the position sensor 205. If shifting is instructed, the process proceeds to step S6. If not instructed, the process returns.
Step S6: The controller 206 determines whether or not an upshift is instructed. If an upshift is instructed, the process proceeds to step S7. If not, the process proceeds to step S8.
Step S7: The target speed ratio determining means 253 of the control unit 206 determines the speed ratio α for upshifting._iUPIs set to the target gear ratio α.
Step S8: The target gear ratio determining means 253 of the control unit 206 determines the gear ratio α for downshift._iDOWNIs set to the target gear ratio α.
Step S9: The controller 206 determines that the target speed ratio α is the minimum speed ratio α._MINLarger and maximum gear ratio α_MAXDetermine if less than. Gear ratio α is the minimum gear ratio α_MINLarger and maximum gear ratio α_MAXIf smaller, the process proceeds to step S10, where the speed ratio α is the minimum speed ratio α._MINOr the maximum gear ratio α_MAXIf it is above, return.
Step S10: The controller 206 controls the engine speed N corresponding to the target speed ratio α._eIs calculated.
Step S11: The controller 206 controls the engine speed N_eIs the minimum speed N_MINHigher and maximum speed N_MAXDetermine if it is lower. Engine speed N_eIs the minimum speed N_MINHigher and maximum speed N_MAXIf lower, the process proceeds to step S12, and the engine speed N_eIs the minimum speed N_MINOr the maximum rotational speed N_MAXIf it is above, return.
Step S12: The control unit 206 sets the target gear ratio α and returns.
[0046]
In the present embodiment, the reference gear ratio α_MIs repeatedly multiplied by a gear ratio constant 1 / r, r a number of times corresponding to the gear position, so that the gear ratio α_iIs calculated, but the vehicle speed N when the stepless speed change mode is shifted to the stepped speed change mode is calculated._O, Gear ratio α and engine speed N_eIt is also possible to refer to a map in which the gear ratio α is set in correspondence with
[0047]
【The invention's effect】
As described above in detail, according to the present invention, in the continuously variable transmission, a continuously variable transmission that performs a speed change with a continuously variable transmission ratio, an actuator that changes the gear ratio of the continuously variable transmission, A shift mode determining means for determining whether or not the transition from the continuously variable transmission mode to the stepped transmission mode, a reference transmission ratio calculating means for calculating a transmission ratio when shifting from the continuously variable transmission mode to the stepped transmission mode, Based on the transmission ratio calculated by the reference transmission ratio calculation means, a transmission ratio sequence calculation means for calculating a plurality of transmission ratios suitable for upshifting and downshifting, and a continuously variable transmission mode When shifting to the stepped speed change mode, the speed ratio calculated by the reference speed ratio calculating means is fixed as a target speed ratio, and thereafter, from a plurality of speed ratios calculated by the speed ratio sequence calculating means Target gear ratio determining means for determining a target gear ratio corresponding to an upshift gear shift instruction and a downshift gear shift instruction; and an actuator actuating means for operating the actuator so that the target gear ratio is achieved. Have
[0048]
In this case, when shifting from the continuously variable transmission mode to the stepped transmission mode, the target transmission ratio determination unit fixes the transmission ratio calculated by the reference transmission ratio calculation unit as the target transmission ratio, and then calculates the transmission ratio sequence. A target gear ratio corresponding to an upshift gearshift instruction and a downshift gearshift instruction is determined from the plurality of gear ratios calculated by the means.
[0049]
Therefore, in the stepped speed change mode, the difference in speed ratio between adjacent speeds becomes appropriate, so that the driver can not only experience the upshift or downshift, but also generate a shift shock. Can be prevented. In addition, it is possible to expect a gear ratio when an upshift or a downshift is performed.
[0050]
Furthermore, in the stepped speed change mode, a plurality of speed ratios are calculated based on the speed ratio when the stepless speed change mode is changed to the stepped speed change mode. To do.
Therefore, since the V belt does not always hit the same part of the primary pulley and the secondary pulley, the primary pulley and the secondary pulley are not locally worn, and the durability of the continuously variable transmission can be improved. .
[0051]
In another continuously variable transmission according to the present invention, the gear ratio sequence calculating unit multiplies the gear ratio calculated by the reference gear ratio calculating unit by an upshift gear constant and a downshift gear constant. Thus, the plurality of gear ratios are calculated. In this case, since the difference in the gear ratio between the respective shift speeds is constant, the shift feeling in the upshift and the shift feeling in the downshift are constant.
[Brief description of the drawings]
FIG. 1 is a functional block diagram of a continuously variable transmission according to an embodiment of the present invention.
FIG. 2 is a schematic diagram of a continuously variable transmission according to an embodiment of the present invention.
FIG. 3 is a hydraulic circuit diagram of a continuously variable transmission according to an embodiment of the present invention.
FIG. 4 is a block diagram of a control device for a continuously variable transmission according to an embodiment of the present invention.
FIG. 5 is a schematic view of a speed selecting device according to an embodiment of the present invention.
FIG. 6 is a flowchart showing an operation of the continuously variable transmission according to the embodiment of the present invention.
[Explanation of symbols]
11 continuously variable transmission
12 continuously variable transmission
43 Hydraulic actuator
205 Position sensor
206 Control unit
250 Shift mode judgment means
251 Reference gear ratio calculation means
252 Gear ratio sequence calculating means
253 Target speed ratio determining means
254 Actuator operation means

Claims (2)

A continuously variable transmission that shifts at a continuously variable transmission ratio, an actuator that changes the variable gear ratio of the continuously variable transmission, and a shift mode determining means that determines whether or not a transition from the continuously variable transmission mode to the stepped transmission mode is made. A reference speed ratio calculating means for calculating a speed ratio when the stepless speed change mode shifts to the stepped speed change mode, and a shift ratio of the upshift based on the speed ratio calculated by the reference speed ratio calculation means. A speed ratio sequence calculating means for calculating a plurality of speed ratios suitable for downshifting, and a speed change calculated by the reference speed ratio calculating means when the stepless speed change mode is shifted to the stepped speed change mode. The ratio is fixed as a target gear ratio, and then, from the plurality of gear ratios calculated by the gear ratio sequence calculation means, an instruction corresponding to an upshift gearshift instruction and a downshift gearshift instruction is provided. A target gear ratio determining means for determining a gear ratio, continuously variable transmission, characterized in that an actuator actuating means for actuating the actuator so that the speed ratio of the target is achieved. 2. The gear ratio sequence calculating means calculates the plurality of gear ratios by multiplying the speed ratio calculated by the reference speed ratio calculating means by an upshift speed constant and a downshift speed constant. The continuously variable transmission as described.

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