JP2004144139A - Transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To implement miniaturization, downsizing, and weight saving of a transmission constituted by disposing a continuously variable transmission mechanism and a stepped rotation transmitting mechanism in parallel, as far as possible. <P>SOLUTION: A belt type continuously variable transmission mechanism CVT is disposed in parallel with a LOW rotation transmitting mechanism GT. The continuously variable transmission mechanism comprises: a drive pulley 30 disposed on a main shaft 17; a driven pulley 35 disposed on a countershaft 18; a metal belt 34 stretched between the drive pulley and the driven pulley; a drive pulley cylinder 33 for variably setting a width of the drive pulley; and a driven pulley piston 38 for variably setting a width of the driven pulley. On the main shaft 17, the drive pulley cylinder 33 is arranged on a left side and a forward/reverse switching mechanism 60 is arranged on a right side, when the driven pulley is set as the center. Further, on the countershaft 18, a LOW clutch 46 is arranged on a left side and the driven pulley piston 38 is arranged on a right side, when the driven pulley is set as the center. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a transmission having a continuously variable transmission mechanism and a stepped rotation transmission mechanism arranged in parallel between an input shaft and an output shaft.
[0002]
[Prior art]
Such a transmission having a continuously variable transmission mechanism and a stepped rotation transmission mechanism (a rotation transmission mechanism formed of a gear train) in parallel has been conventionally known (for example, Patent Document 1 and Patent Document 1). 2). For example, the transmission disclosed in Patent Literature 1 includes a torque converter that receives an input from an engine, and a reduction gear train (parallel) that is arranged in parallel between a transmission input shaft connected to the torque converter and a transmission output shaft. (A gear-type rotation transmission mechanism, that is, a stepped rotation transmission mechanism) and a belt-type continuously variable transmission mechanism. In this transmission, a first hydraulic clutch for transmitting power by a reduction gear train and a second hydraulic clutch for transmitting power by a belt-type continuously variable transmission mechanism are arranged on a transmission input shaft. A planetary gear unit for switching between forward and backward movement is provided on the transmission output shaft. Note that a transmission having a similar configuration is also disclosed in Patent Document 2 (see FIGS. 1 and 2).
[0003]
In the transmission having such a configuration, the speed ratio of the reduction gear train is set to be lower than the lowest speed ratio of the belt-type continuously variable transmission mechanism, and the first hydraulic clutch is engaged when the vehicle starts. And transmitting the rotational driving force of the engine to the wheels via a reduction gear train to start the vehicle, and then releasing the first hydraulic clutch and engaging the second hydraulic clutch to thereby transmit a belt-type continuously variable transmission. , And the vehicle is controlled so as to start and run smoothly by performing stepless shift control.
[0004]
In FIG. 3 of Patent Document 2, the reduction gear train is configured by providing a low-speed gear train and a high-speed gear train in parallel, and the low-speed gear train has a lower gear ratio than the lowest speed ratio of the continuously variable transmission mechanism. , And the gear train for high speed is set to a speed ratio higher than the highest speed ratio of the continuously variable transmission mechanism. In this transmission, when the vehicle starts, power is transmitted by a low-speed gear train, and thereafter, the speed is controlled by switching to a power transmission mechanism using a continuously variable transmission mechanism, so that the gear ratio of the continuously variable transmission mechanism becomes the maximum gear ratio. After reaching, power transmission by a high-speed gear train is performed.
[0005]
[Patent Document 1] JP-B-63-14228 [Patent Document 2] JP-A-2002-48213
[Problems to be solved by the invention]
As described above, a transmission configured by having a continuously variable transmission mechanism and a stepped rotation transmission mechanism in parallel has, for example, a belt-type continuously variable transmission mechanism between input and output shafts, and It is necessary to dispose a gear train constituting a stepped rotation transmitting mechanism on the side, and further provide a forward / reverse switching mechanism and a starting clutch (hydraulic clutch). For this reason, it is necessary to increase the number of shafts constituting the transmission to increase the number of shafts, or to increase the axial dimension of the transmission, thereby increasing the size and weight of the transmission. There is a problem that there is a possibility.
[0007]
The present invention has been made in view of such a problem, and an object of the present invention is to make a transmission constituted by a continuously variable transmission mechanism and a stepped rotation transmission mechanism in parallel as small, compact and lightweight as possible. And
[0008]
[Means for Solving the Problems]
To achieve such an object, the transmission according to the present invention uses an input shaft (for example, the main shaft 17 in the embodiment) input from a drive source to input rotation driving force to an output shaft (for example, the countershaft in the embodiment). 18), a continuously variable transmission mechanism (for example, a belt-type continuously variable transmission mechanism CVT in the embodiment) and a stepped rotation transmission mechanism (for example, a LOW rotation transmission mechanism GT in the embodiment) that are provided in parallel, A continuously variable transmission mechanism includes a drive pulley having a variable pulley width disposed on an input shaft, a driven pulley having a variable pulley width disposed on an output shaft, and an endless bridge stretched between the drive pulley and the driven pulley. A belt (for example, the metal belt 34 in the embodiment) and a drive pulley disposed on an axial side of the drive pulley and variably setting the drive pulley width. A re-actuator (for example, the drive pulley cylinder 33 and the drive pulley oil chamber 33a in the embodiment) and a driven pulley actuator (for example, the driven in the embodiment) which is disposed on the axial side of the driven pulley and variably sets the driven pulley width. It comprises a pulley piston 38 and a driven pulley oil chamber 38a). The input shaft further includes a forward / reverse switching mechanism disposed in the continuously variable transmission mechanism, and friction engagement means (for example, the LOW clutch 46 in the embodiment) for establishing a power transmission path by the stepped rotation transmission mechanism. In the above, a drive pulley actuator is provided on one side in the axial direction with the drive pulley as a center, and one of a forward / reverse switching mechanism and a friction engagement means is provided on the other side in the axial direction, On the shaft, the other of the forward / reverse switching mechanism and the friction engagement means is disposed on one side in the axial direction with the driven pulley as the center, and the driven pulley actuator is disposed on the other side in the axial direction.
[0009]
According to the transmission of the present invention having such a configuration, since the continuously variable transmission mechanism is constituted by the belt-type continuously variable transmission mechanism in which the endless belt is stretched between the drive and the driven pulley, the drive and the driven pulley are provided. Are disposed on the input and output shafts, respectively, and are disposed in a positional relationship of being overlapped in the axial direction (a relationship of having the same axial position). Then, the drive pulley actuator is disposed on the input shaft on one axial side with respect to the drive pulley, and the driven pulley actuator is disposed on the output shaft on the other axial side with respect to the driven pulley. For this reason, a space is generated on the other side in the axial direction of the drive pulley on the input shaft, and a space is generated on one side in the axial direction of the driven pulley on the output shaft. In the transmission according to the present invention, these spaces are formed. A forward / reverse switching mechanism and a friction engagement means are provided at the front end. As a result, an increase in the axial dimension of the entire transmission can be suppressed, and the transmission can be reduced in size and size. Further, the drive and driven pulley, the forward / reverse switching mechanism, and the friction engagement means can all be efficiently disposed on the input shaft and the output shaft, and there is no need to make the transmission multi-axial. The size and weight of the transmission can be reduced.
[0010]
Note that the stepped rotation transmission mechanism includes a drive gear provided on the input shaft (for example, the LOW drive gear 41 in the embodiment) and a driven gear provided on the output shaft (for example, the LOW driven gear 45 in the embodiment). ) And an idle gear (for example, the LOW idle gear 42 in the embodiment) disposed in mesh with the drive gear and the driven gear, and one of the drive gear and the driven gear is one of the input shaft and the output shaft. It is preferable to be arranged so as to be rotatable on the above and to be freely disengageable from one of the above-mentioned shafts by a frictional engagement means. By configuring the stepped rotation transmission mechanism with a single gear train in this manner, this gear train can be disposed compactly on the side of the belt-type continuously variable transmission mechanism, and it is easy to make the transmission small and compact. It is.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. 1 to 5 show a transmission according to a preferred embodiment of the present invention, FIG. 1 shows an overall cross section, FIG. 2 shows a power transmission mechanism configuration, and FIGS. A portion above the center axis S1 of the machine main shaft 17, a portion between the center axis S1 and the center axis S2 of the transmission counter shaft 18, and a portion below the center axis S2 are enlarged.
[0012]
This transmission TM is configured by disposing a transmission mechanism in a casing 11 including a converter case 12, a center case 14, a left case 15, and a cover 16. In the casing 11, a main shaft 17 and a counter shaft 18 are rotatably supported by bearings, respectively, and extend in parallel with each other. A torque converter 20 is provided in converter case 12, and the right end of main shaft 17 protrudes into torque converter 20. Converter case 12 is connected to the output shaft end of the housing of the engine, and pump impeller 22 of torque converter 20 is connected to engine output shaft (crankshaft) 19 via drive plate 21.
[0013]
The torque converter 20 has a turbine runner 23 and a stator 24 in addition to the pump impeller 22. The turbine runner 23 is spline-coupled to an end of the main shaft 17, and the stator 24 is fixed to the casing 11. A lock-up clutch 26 is provided on the inner surface side of a side cover 25 which is connected to the pump impeller 22 and is provided so as to surround the turbine runner 23. The lock-up clutch 26 includes a disk-shaped piston 27 slidably supported on the outer peripheral surface of a boss 23 a of the turbine runner 23. A matable friction lining 28 is applied.
[0014]
In the lock-up clutch 26, the hydraulic pressure in the converter internal space in which the pump impeller 22, the turbine runner 23 and the stator 24 are disposed acts so as to press the piston 27 rightward in the drawing, and the piston 27 and the side cover 25 The hydraulic pressure in the lock-up oil chamber space 27a surrounded by the above acts to press the piston 27 to the left. The lock-up control hydraulic pressure supplied through a shaft hole 27b formed in the main shaft 17 to extend in the axial direction is supplied to the lock-up hydraulic space 27a. As a result, control is performed to bring the friction lining 28 of the piston 27 into contact with the inner peripheral surface of the side cover 25 in accordance with the balance with the oil pressure in the converter internal space, and engagement control of the lock-up clutch is performed.
[0015]
On the other hand, a belt-type continuously variable transmission mechanism CVT and a stepped (one-step) LOW rotation transmission mechanism GT are arranged in parallel across the main shaft 17 and the counter shaft 18.
[0016]
The belt-type continuously variable transmission CVT includes a drive pulley 30 supported on the main shaft 17, a driven pulley 35 supported on the counter shaft 18, and a metal belt 34 wound around the drive pulley 30 and the driven pulley 35. Is provided. The drive pulley 30 is disposed on the main shaft 17 so as to be rotatable relative to the fixed side pulley half 31, and is disposed movably in the axial direction so as to approach / separate from the fixed side pulley half 31. The driven pulley 35 includes a fixed-side pulley half 36 connected to and disposed on the countershaft 18, and a driven-side pulley half 36 that approaches and separates from the fixed-side pulley half 36. And a movable pulley half 37 disposed so as to be movable in the axial direction.
[0017]
A forward / reverse switching mechanism 60 using a single pinion type planetary gear mechanism is provided on the main shaft 17 adjacent to the drive pulley 30. The forward / reverse switching mechanism 60 includes a sun gear 61 connected to the main shaft 17, a ring gear 62 rotatably disposed on the main shaft 17 so as to surround the outer periphery of the sun gear 61 at a distance, and a main gear 17. A carrier 63 rotatably supported by the carrier 63 and a plurality of planetary gears 64 rotatably supported by the carrier 63 and simultaneously meshing with the sun gear 61 and the ring gear 62 are provided. Further, the ring gear 62 is connected to the drive pulley 30, and the ring gear 62 and the drive pulley 30 connected in this manner are engaged with and disengaged from the sun gear 61 (and the main shaft 17) via a wet-type multi-plate forward clutch 65. It is possible. Further, the carrier 63 is engaged with and disengaged from the casing 11 by a wet multi-plate reverse brake 66 so as to be fixedly held.
[0018]
During forward running of the vehicle, the forward clutch 65 is engaged, the sun gear 61 and the ring gear 62 and the drive pulley 30 that rotate integrally with the main shaft 17 are connected, and the main shaft 17 and the drive pulley 30 rotate integrally. The rotation of 17 is transmitted to the drive pulley 30 as it is.
[0019]
When the vehicle travels backward, the reverse brake 66 is engaged, and the carrier 63 is connected to the casing 11 and fixed and held. For this reason, the rotation of the sun gear 61 coupled to the main shaft 17 is reduced in the planetary gear mechanism and the direction is reversed and transmitted to the ring gear 62, and the ring gear 62 is rotated at a lower speed and in the opposite direction than the main shaft 17, This rotation is transmitted to the drive pulley 30 connected to the ring gear 62.
[0020]
As described above, the drive pulley 30 is driven to rotate forward (toward the same rotational direction as the main shaft 17) or backward (toward the rotational direction opposite to the main shaft 17), and this rotation is performed via the metal belt 34. The power is transmitted to the driven pulley 31. When the rotational power is transmitted by the belt-type continuously variable transmission mechanism CVT in this manner, control for continuously changing the speed ratio is performed. This continuously variable transmission control is performed by moving the movable pulley half 32 of the drive pulley 30 and the movable pulley half 37 of the driven pulley 35 in the axial direction.
[0021]
For this reason, a drive pulley cylinder 33 is attached to the side surface of the movable pulley half 32 of the drive pulley 30, and a drive pulley piston portion 32 a formed on the side of the movable pulley half 32 is connected to the drive pulley. A drive pulley oil chamber 33a is formed inside the cylinder 33 so as to be freely slidable. A driven pulley piston 38 is attached to a side surface of the movable pulley half 37 of the driven pulley 35, and a driven pulley piston 37 is attached to a driven pulley cylinder 37a formed on the side of the movable pulley half 37. The driven pulley oil chamber 38a is formed inside the driven pulley oil chamber 38a. Then, a pulley control oil pressure is supplied into the drive pulley oil chamber 33a and the driven pulley oil chamber 38a from a hydraulic control valve HV described later, and the movable pulley half 32 of the drive pulley 30 and the movable pulley half 37 of the driven pulley 35 are driven. Is moved in the axial direction to control the gear ratio continuously.
[0022]
The LOW rotation transmission mechanism GT includes a LOW drive gear 41 connected to the left end of the main shaft 17, a LOW idle gear 42 rotatably supported by the casing 11 and meshing with the LOW drive gear 41, and a countershaft 18. The LOW driven gear 45 is rotatably disposed at the left end and meshes with the LOW idle gear 42. The LOW driven gear 45 is connected to the counter shaft 18 via a one-way clutch 44 and a wet-type multi-plate LOW clutch 46 in series. Therefore, the power transmission control via the LOW rotation transmission mechanism GT is possible by the engagement / disengagement control of the LOW clutch 46, and the driving rotation in the forward direction is performed by the action of the one-way clutch 44 even when the LOW clutch 46 is engaged. Only the LOW driven gear 45 is transmitted to the counter shaft 18.
[0023]
As can be understood from the above configuration, a power transmission path from the main shaft 17 to the counter shaft 18 is formed by the forward / reverse switching mechanism 60 and the continuously variable transmission mechanism CVT, and the counter is also transmitted from the main shaft 17 by the LOW rotation transmission mechanism GT. A power transmission path to the shaft 18 is formed, and these two power transmission paths are formed in parallel. The speed ratio (gear ratio) R (GT) of the LOW rotation transmission mechanism GT is set to a speed lower than the lowest speed ratio R (LOW) of the continuously variable transmission mechanism CVT.
[0024]
At the right end of the counter shaft 18, a final drive gear 47 is connected and arranged. This final drive gear 47 meshes with a first reduction gear 49 which is connected and arranged to a reduction shaft 48 rotatably supported by the casing 11. The second reduction gear 50 connected to the reduction shaft 48 meshes with the final driven gear 53 connected to the differential box 52 of the differential mechanism 51. The differential mechanism 51 is a well-known one, and is fixed to differential pinions 55 and 55 rotatably supported by a pinion shaft 54 provided in the differential box 52 and left and right axles 56L and 56R inserted into the differential box 52. It is constituted by differential side gears 57, 57 meshing with the differential pinions 55, 55. As can be seen from this configuration, the rotation of the counter shaft 18 is transmitted to the left and right axles 56L, 56R via the gear train having the above configuration. This rotation transmission mechanism is referred to as a final rotation transmission mechanism FG.
[0025]
The structure of the transmission TM is characterized by the arrangement of the forward / reverse switching mechanism 60, the belt-type continuously variable transmission CVT, and the LOW rotation transmission mechanism GT. This will be described with reference to FIG. The belt-type continuously variable transmission mechanism CVT is configured by extending a metal belt 34 between a drive pulley 30 and a driven pulley 35, and the drive pulley 30 and the driven pulley 35 overlap with the main shaft 17 and the countershaft 18 in an axial direction. They are arranged with a relationship (a relationship that results in the same axial position). In addition, a drive pulley cylinder 33 for variably setting the pulley width of the drive pulley 30 is disposed on the left side of the drive pulley 30, and a driven pulley piston 38 for variably setting the pulley width of the driven pulley 35 is provided. 35 is provided on the right side. A forward / reverse switching mechanism 60 is disposed on the right side of the drive pulley 30 on the main shaft 17 (ie, on the opposite side of the drive pulley cylinder 33 with the drive pulley 30 at the center). A LOW clutch 46 is provided on the left side (that is, the half of the driven pulley piston 38 with the driven pulley 35 at the center).
[0026]
If the drive pulley 30, the driven pulley 35, the forward / reverse switching mechanism 60, and the LOW clutch 46 are arranged so as to have the above positional relationship, these can be efficiently arranged inside the casing 11, An increase in the axial dimension of the entire transmission can be suppressed. Further, only the main shaft 17 and the counter shaft 18 are required as described above, and it is not necessary to make the transmission multi-axial, so that the size and weight of the transmission can be reduced.
[0027]
[Start running control]
An operation of the transmission TM configured as described above, that is, an example of starting and running control of the vehicle will be described with reference to a control device shown in FIG.
[0028]
First, the configuration of the control device in FIG. 6 will be described. The control device includes a hydraulic control valve HV for controlling and supplying control hydraulic pressure to the LOW clutch 46, the forward clutch 65, the reverse brake 66, the drive pulley oil chamber 33a and the driven pulley oil chamber 38a in the transmission TM. And a control unit ECU that controls the operation of the hydraulic control valve HV. Specifically, the energizing operation control of the solenoid valve constituting the hydraulic control valve HV is performed based on a control signal from the control unit ECU. For such control signal output control, the control unit ECU provides the engine rotation signal Ne from the engine rotation sensor 71, the main shaft rotation signal Nm from the main shaft rotation sensor 72, and the counter shaft rotation from the counter shaft rotation sensor 73. The signal Nc, the drive pulley rotation signal ND from the drive pulley rotation sensor 74, and the shift position signal Sp from the shift position sensor 77 are sent. The counter shaft rotation signal Nc may be a vehicle speed signal. The shift position sensor 77 detects the operating position of the shift lever operated by the driver in the driver's seat. For example, when the shift lever is operated to the R (reverse), N (neutral), or D (drive) range position, In response, the R, N, D position signals are sent to the control unit ECU.
[0029]
[Neutral stop control]
First, the neutral stop control performed when the driver operates the shift lever to the N range position will be described. At this time, the control oil pressure to the LOW clutch 46, the forward clutch 65, and the reverse brake 66 is set to almost zero to release all of them, and the speed ratio of the continuously variable transmission mechanism CVT is set to a predetermined speed ratio (for example, The supply of the control oil pressure to the drive pulley oil chamber 33a and the driven pulley oil chamber 38a is controlled so as to achieve a low speed gear ratio. As a result, the power transmission of the continuously variable transmission mechanism CVT is interrupted by the forward / reverse switching mechanism 60 at the predetermined gear ratio, the power transmission of the LOW rotation transmission mechanism GT is interrupted by the LOW clutch 46, and the transmission TM is in the neutral state. It becomes.
[0030]
[Forward start control]
Next, the forward start control of the vehicle will be described first. This control is performed when the driver operates the shift lever to the D (drive) range position from when the vehicle is stopped and the shift lever is at the N (neutral) range position. When the shift lever is operated from the N range position to the D range position, this is detected by the shift position sensor 77, and a D position signal is sent to the control unit ECU. Upon receiving this signal, the control unit ECU first supplies the forward clutch 65 with a relatively low-pressure hydraulic pressure (engagement control hydraulic pressure lower than the maximum engagement control hydraulic pressure) that gently engages the forward clutch 65. The operation of the hydraulic control valve HV is controlled.
[0031]
As a result, a state where the rotational driving force of the engine E is transmitted to the wheels via the torque converter 20, the forward / reverse switching mechanism 60, the continuously variable transmission mechanism CVT, and the final rotation transmission mechanism FG, that is, an in-gear state is established. Here, the speed ratio (gear ratio) R (GT) of the LOW rotation transmission mechanism GT is set to a speed lower than the lowest speed ratio R (LOW) of the continuously variable transmission mechanism CVT, and the forward clutch 65 Since the wheels are gently engaged with relatively low hydraulic pressure, a small torque is gently transmitted to the wheels, and there is no shock caused by the in-gear. In order to prevent the occurrence of the in-gear shock, the speed ratio of the continuously variable transmission mechanism CVT is preferably set to a predetermined speed ratio higher than the minimum speed speed ratio R (LOW). However, considering a smooth transition to the running control thereafter, it is preferable to set the speed ratio within a range necessary for suppressing the occurrence of the in-gear shock and to set the speed ratio to a predetermined speed ratio as low as possible. . The predetermined gear ratio is set to an optimum value according to the characteristics of the vehicle (for example, vehicle weight) and the use conditions (for example, transmission oil temperature).
[0032]
After initiating the in-gear control by gently engaging the forward clutch 65 in this manner, the control unit ECU immediately releases the forward clutch 65 and controls the hydraulic pressure to shift to the engagement control of the LOW clutch 46. The operation of the valve HV is controlled. That is, the forward clutch 65 is only for performing smooth in-gear without shock, and actual start control is performed by engaging the LOW clutch 46. Note that the timing for releasing the forward clutch 65 and shifting to the engagement control of the LOW clutch 46 is preset by a timer. Alternatively, the shift timing may be determined by detecting a change in the rotation of the counter shaft 18.
[0033]
As described above, when the shift lever is operated from the N (neutral) range position to the D (drive) range position, first, the forward clutch 65 is gently engaged to set the speed ratio to a relatively high speed side. The state is shifted to the in-gear state via the step-variable mechanism CVT, and thereafter, the control immediately shifts to the engagement control of the LOW clutch 46 to perform the starting control. As described above, control called so-called "squat control" is performed, and smooth start control is possible by performing in-gear control without shock.
[0034]
When the control shifts to the engagement control of the LOW clutch 46 as described above, the rotational driving force of the engine E is transmitted to the wheels at the lowest speed ratio R (GT) via the LOW rotation transmission mechanism GT. At this time, when the accelerator pedal is not depressed, the engine is in an idling state, and engagement control of the LOW clutch 46 is performed so that so-called creep torque is transmitted to the wheels. Thereafter, when the accelerator pedal is depressed, the LOW clutch 46 is further engaged, the engine output is transmitted to the wheels at the minimum speed ratio R (GT), and the vehicle starts.
[0035]
[Vehicle forward running control]
After the vehicle starts in this manner, the forward clutch 65 is engaged while the LOW clutch 46 is engaged in accordance with the increase in the traveling speed, and the process shifts to power transmission by the continuously variable transmission mechanism CVT. Then, the traveling control of the vehicle is performed by controlling the speed ratio of the continuously variable transmission mechanism CVT to be steplessly changed according to, for example, the accelerator opening and the vehicle speed. For example, shift control is performed such that the actual drive pulley rotation speed NDRa matches the target drive pulley rotation speed NDRo.
[0036]
[Vehicle reverse start and travel control]
On the other hand, the control of starting the vehicle in the reverse direction and running the vehicle is performed by controlling the engagement of the reverse brake 66. As described above, when the reverse brake 66 is engaged, the carrier 63 is fixed and held, and the rotation of the sun gear 61 connected to the main shaft 17 is reduced in the planetary gear mechanism and the direction is reversed and transmitted to the ring gear 62. , To the drive pulley 30 coupled to the ring gear 62. Then, the rotational driving force is transmitted from the continuously variable transmission mechanism CVT to the wheels via the final rotation transmission mechanism FG, and the starting and traveling control in the reverse direction are performed. Here, the minimum speed ratio R (LOW) of the continuously variable transmission mechanism CVT is a speed ratio higher than the speed ratio R (GT) of the LOW rotation transmission mechanism GT. However, during reverse traveling, the rotation of the main shaft 17 is reduced by the planetary gear mechanism 60 and transmitted to the drive pulley 30. Therefore, the overall speed ratio at the time of reverse travel is substantially the same as the speed ratio R (GT) via the LOW rotation transmission mechanism GT at the time of forward start, and the same start torque as at the time of reverse start as at the time of forward start. To the wheels.
[0037]
【The invention's effect】
As described above, according to the present invention, a transmission is configured in parallel with the continuously variable transmission mechanism and the stepped rotation transmission mechanism, and the continuously variable transmission mechanism spans the endless belt between the drive and the driven pulley. The drive and the driven pulley are arranged on the input and output shafts, respectively, and are arranged in a positional relationship overlapping in the axial direction (a relationship of the same axial position). Above, the drive pulley actuator is disposed on one side in the axial direction with respect to the drive pulley on the input shaft, and the driven pulley actuator is disposed on the other side in the axial direction with respect to the driven pulley on the output shaft. For this reason, a space is generated on the other side in the axial direction of the drive pulley on the input shaft, and a space is generated on one side in the axial direction of the driven pulley on the output shaft. In the transmission according to the present invention, these spaces are formed. Is provided with a forward / reverse switching mechanism and friction engagement means, whereby it is possible to suppress an increase in the axial dimension of the entire transmission, and to reduce the size and size of the transmission. Further, the drive and driven pulley, the forward / reverse switching mechanism, and the friction engagement means can all be efficiently disposed on the input shaft and the output shaft, and there is no need to make the transmission multi-axial. The size and weight of the transmission can be reduced.
[0038]
Note that the stepped rotation transmission mechanism is constituted by a drive gear provided on the input shaft, a driven gear provided on the output shaft, and an idle gear provided in mesh with the drive gear and the driven gear. One of the drive gear and the driven gear is rotatably disposed on one of the input shaft and the output shaft, and is configured to be freely disengageable from the one of the shafts by friction engagement means. Is preferred. By configuring the stepped rotation transmission mechanism with a single gear train in this manner, this gear train can be disposed compactly on the side of the belt-type continuously variable transmission mechanism, and it is easy to make the transmission small and compact. It is.
[Brief description of the drawings]
FIG. 1 is an overall sectional view showing an internal power transmission mechanism structure of a vehicle transmission according to a preferred embodiment of the present invention.
FIG. 2 is a skeleton diagram showing a power transmission path configuration of the vehicle transmission.
FIG. 3 is an enlarged partial cross-sectional view showing a portion above a central axis of a main shaft of the vehicle transmission.
FIG. 4 is an enlarged partial cross-sectional view illustrating a portion between a main shaft center axis and a counter shaft center axis of the vehicle transmission.
FIG. 5 is an enlarged partial cross-sectional view showing a portion below a central axis of a counter shaft of the vehicle transmission.
FIG. 6 is a block diagram showing a configuration of a control device of the vehicle transmission.
[Explanation of symbols]
TM transmission CVT stepless speed change mechanism GT LOW rotation transmission mechanism 17 main shaft 18 counter shaft 41 LOW drive gear 42 LOW idle gear 45 LOW driven gear 46 LOW clutch 60 forward / reverse switching mechanism 65 forward clutch 66 reverse clutch

Claims (2)

In a transmission having a continuously variable transmission mechanism and a stepped rotation transmission mechanism that transmit an input rotation driving force input to an input shaft from a drive source to an output shaft in parallel,
The continuously variable transmission mechanism has a variable pulley width drive pulley disposed on the input shaft, a variable pulley width driven pulley disposed on the output shaft, and a drive pulley and the driven pulley. An endless belt, a drive pulley actuator disposed on the axial side of the drive pulley and variably setting the drive pulley width, and a driven pulley width disposed on the axial side of the driven pulley. It consists of a driven pulley actuator that can be set variably,
A forward / reverse switching mechanism disposed in the continuously variable transmission mechanism, and friction engagement means for establishing a power transmission path by the stepped rotation transmission mechanism;
On the input shaft, the drive pulley actuator is disposed on one side in the axial direction with the drive pulley as the center, and one of the forward / reverse switching mechanism and the friction engagement means is provided on the other side in the axial direction. One is arranged,
On the output shaft, the other of the forward-reverse switching mechanism and the friction engagement means is disposed on one side in the axial direction with the driven pulley as a center, and the driven pulley actuator is disposed on the other side in the axial direction. A transmission characterized by being arranged and configured. A drive gear disposed on the input shaft, a driven gear disposed on the output shaft, and an idle gear disposed in mesh with the drive gear and the driven gear. Consisting of
One of the drive gear and the driven gear is rotatably disposed on one of the input shaft and the output shaft, and is freely disengageable from the one of the shafts by the friction engagement means. The transmission according to claim 1, wherein the transmission comprises:

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