JP3572979B2 - Belt type continuously variable transmission - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a belt-type continuously variable transmission having a starting clutch.
[0002]
[Prior art]
Conventionally, two pulleys on the input side and the output side and a belt wound around them are provided, and the groove widths of these two pulleys are arbitrarily changed while synchronizing with each other to thereby rotate the output side pulley. 2. Description of the Related Art A belt-type continuously variable transmission capable of continuously changing the speed is known.
[0003]
When such a belt-type continuously variable transmission is used, a torque converter, an electromagnetic clutch, or a wet multi-plate clutch (hereinafter, referred to as a connecting / disconnecting means) for connecting / disconnecting a power transmission path between an engine and a driving wheel is used. , A start clutch) is used, and the shock accompanying the input of the engine rotation at the time of start or the like is reduced through these connecting / disconnecting means.
[0004]
By the way, the torque converter and the electromagnetic clutch are generally provided at the connection between the engine and the transmission on the axis of the primary shaft, while the starting clutch is provided on the secondary shaft. For example, FIG. 3 is a side sectional view showing the structure of a conventional belt-type continuously variable transmission having a start clutch. An output shaft (crankshaft) of an engine is provided on the left side of a primary shaft 51, and a belt-type continuously variable transmission is provided. The rotation is input to the continuously variable transmission. In this conventional belt-type continuously variable transmission, the starting clutch 53 is provided on the secondary shaft 52 on the downstream side of the secondary pulley 55 to disconnect and connect the transmission of rotation between the secondary shaft 52 and the drive gear 54. I was
[0005]
[Problems to be solved by the invention]
In recent years, a hybrid vehicle combining an engine and an electric motor has been developed. Although there are various methods for arranging the engine and the electric motor in the hybrid vehicle, it is conceivable to arrange the electric motor in the transmission coaxially with the primary shaft.
[0006]
However, in the case of the belt-type continuously variable transmission having the above-described conventional start clutch, the start clutch 53 is provided on the secondary shaft 52. It will interfere with the clutch 53. Further, if the diameter of the starting clutch 53 is reduced so as to avoid interference, it is not possible to secure a sufficient clutch capacity. If the number of clutch plates is increased in order to secure the clutch capacity, the The shaft length increases, and the entire transmission 50 becomes large.
[0007]
Furthermore, not only the hybrid vehicle, but also the secondary shaft 52 has a high rotational speed and a large differential rotational speed between the secondary shaft 52 and the drive gear 54 at the time of starting. There is also a problem of concern.
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has been made to improve the durability of a starting clutch and to be applicable to a hybrid vehicle having an electric motor on a primary shaft. It is an object to provide a transmission.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, in the belt-type continuously variable transmission according to the present invention, by changing the groove width of the primary pulley and the groove width of the secondary pulley in conjunction with each other, transmission is performed from the primary shaft to the secondary shaft via the belt. The speed of the rotation is continuously variable, and the rotation is transmitted from the secondary shaft to the countershaft by meshing between the drive gear provided on the engine side of the secondary pulley and the driven gear provided on the countershaft on the secondary shaft. Then, a starting clutch for connecting and disconnecting the driven gear and the countershaft so as to transmit the driving force to the drive wheels is disposed closer to the engine than the driven gear on the countershaft.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 show a belt-type continuously variable transmission as one embodiment of the present invention. FIG. 1 is a skeleton diagram showing a schematic configuration of the belt-type continuously variable transmission. In this embodiment (see FIG. 1), the belt-type continuously variable transmission is disposed on the left side of the engine 1 in the plan view. However, as in the conventional example (FIG. 3), the engine and the transmission are separated. It may be arranged left and right reversed. Moreover, as a matter of course, all the rotating shafts 5, 6, 24, 25, 27, 33, and 34 shown in FIG. 1 are arranged in parallel with each other.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, in the belt-type continuously variable transmission according to the present invention, by changing the groove width of the primary pulley and the groove width of the secondary pulley in conjunction with each other, transmission is performed from the primary shaft to the secondary shaft via the belt. The speed of the rotation is continuously variable, and the rotation is transmitted from the secondary shaft to the countershaft by meshing between the drive gear provided on the engine side of the secondary pulley and the driven gear provided on the countershaft on the secondary shaft. to so as to transmit the driving force to the drive wheels, disposed on the engine side than the driven gear on the countershaft of the starting clutch for performing connection disconnection between the driven gear and the counter shaft, further restrain the rotation of the counter shaft Parking gear that is Disposed to gin side.
Also, an electric motor capable of outputting power to the primary shaft is disposed coaxially between the output shaft of the engine and the rotation shaft of the primary pulley.
Further, the drive gear and the driven gear are configured so that the speed is reduced when the rotation is transmitted from the secondary shaft to the counter shaft.
Further, an output gear provided on the counter shaft for outputting the driving force is disposed on the opposite side of the driven gear from the engine.
[0011]
A forward / reverse switching mechanism 4 is provided between the engine 1 and the electric motor 2, and rotations input from the engine 1 and the electric motor 2 are transmitted through the forward / reverse switching mechanism 4. Input to the continuously variable transmission mechanism 20.
As the forward / reverse switching mechanism 4, a planetary gear unit is employed, and an output shaft 6 of the engine 1 is connected to a sun gear 10. The output shaft 5 of the electric motor 2 is connected to a carrier 12 that supports the pinion gear 11. Therefore, the rotation of the engine 1 is input from the sun gear 10, and the rotation of the electric motor 2 is input from the carrier 12. The pinion gear 11 is a double pinion gear including an inner pinion 11a and an outer pinion 11b that mesh with each other.
[0012]
The rotation output from the forward / reverse switching mechanism 4 to the continuously variable transmission mechanism 20 is performed from the carrier 12. In other words, the primary shaft 24 coaxially integrated with the primary pulley 21 of the continuously variable transmission mechanism 20 is connected to the continuously variable transmission mechanism 20 side of the carrier 12, and the engine 1 and the electric motor 1 input to the sun gear 10 and the carrier 12, respectively. The rotation of the motor 2 is output from the carrier 12 to the primary shaft 24.
[0013]
A brake 14 is provided on the ring gear 13, and the rotation of the ring gear 13 can be restricted by operating the brake 14. A clutch 15 is disposed inside the primary shaft 24 of the continuously variable transmission mechanism 20. By connecting the clutch 15, the sun gear 10 and the carrier 12 can be integrally restrained.
[0014]
Therefore, when traveling forward using the engine 1 and the electric motor 2 together, the brake 14 should be turned off and the clutch 15 should be turned on. When traveling backward, the brake 14 should be on and the clutch 15 should be off. Then, the electric motor 2 can be reversed. When the vehicle runs only by the electric motor 2 or performs energy regeneration, both the brake 14 and the clutch 15 may be turned off.
[0015]
Next, the continuously variable transmission mechanism 20 will be described. The continuously variable transmission mechanism 20 includes a primary pulley 21, a secondary pulley 22, and a belt 23, and is input to the primary shaft 24 from the forward / reverse switching mechanism 4. The rotation is input to the secondary pulley 22 via the belt 23 from the primary pulley 21 coaxially integrated with the primary shaft 24.
[0016]
The primary pulley 21 and the secondary pulley 22 each include two sheaves 21a, 21b, 22a, and 22b that rotate integrally. One of the sheaves 21a, 22a is a fixed sheave fixed in the axial direction, and the other sheave 21b, 22b is a movable sheave movable by a hydraulic actuator (see FIG. 2). Here, the movable sheave 21b of the primary pulley 21 is disposed on the side opposite to the engine 1 with respect to the fixed sheave 21a, and the movable sheave 22b of the secondary pulley 22 is disposed on the side opposite to the movable sheave 21b with respect to the belt 23. The length of the secondary shaft 25 described later is kept short.
[0017]
These movable sheaves 21b, 22b are configured to move synchronously. When the speed is reduced, the hydraulic pressure of the movable sheave 22b is increased to reduce the groove width of the secondary pulley 22, and the hydraulic pressure of the movable sheave 21b is reduced. And the groove width of the primary pulley 21 is increased. Conversely, when increasing the speed, the groove width of the primary pulley 21 is reduced and the groove width of the secondary pulley 22 is increased.
[0018]
The rotation that has been shifted by the continuously variable transmission mechanism 20 is output to a secondary shaft 25 that is arranged in parallel with the primary shaft 24 and that rotates coaxially with the secondary pulley 22.
Hereinafter, a detailed description will be given with reference to a sectional side view of a main part in FIG. 2. A drive gear 26 is fixedly provided near an end of the secondary shaft 25 on the engine 1 side. The rotation transmitted to the secondary shaft 25 is output from the drive gear 26 to a driven gear 28 that meshes. The driven gear 28 is rotatably supported by a countershaft 27 arranged side by side with the secondary shaft 25. A start clutch 29 is provided on the engine 1 side of the countershaft 27, and the opposite side across the driven gear 28. Is provided with a differential output gear (output gear) 30. The diameter of the drive gear 26 is smaller than that of the driven gear 28, so that the speed is reduced when the rotation is transmitted from the drive gear 26 to the driven gear 28.
[0019]
The starting clutch 29 is means for connecting and disconnecting the countershaft 27 and the driven gear 28, and employs a wet multi-plate clutch for connecting by friction between a plurality of clutch plates. That is, a clutch hub 40 is coaxially fixed to the driven gear 28, and a clutch drum 41 is coaxially fixed to the counter shaft 27. Drive plates 42 are provided at equal intervals on the outer peripheral surface of the clutch hub 40, and driven plates 43 are provided on the inner peripheral surface of the clutch drum 41 so as to alternately sandwich the drive plates 42. Further, pistons 44 and 45 are provided inside the clutch drum 41, and the hydraulic pressure in the hydraulic chambers 46 and 47 and the urging force of return springs 48 and 49 provided on the opposite side to the hydraulic chambers 46 and 47 are provided. It moves according to the power relationship between
[0020]
First, as the hydraulic pressure in the hydraulic chambers 46 and 47 is increased, the piston 44 moves in the direction of the plates 42 and 43 to press the plates 42 and 43, and the piston 45 also moves in the direction of the plates 42 and 43. Thus, the piston 44 is pressed against the plates 42, 43. As a result, friction occurs between the plates 42 and 43, and the plates 42 and 43 cannot rotate relative to each other. Therefore, in this case, the starting clutch 29 is connected, and the driven gear 28 and the counter shaft 27 are integrated with each other to transmit the rotation from the driven gear 28 to the counter shaft 27.
[0021]
On the other hand, when the hydraulic pressure is released from the hydraulic chambers 46 and 47, the pistons 44 and 45 are pushed back to the original positions by the urging forces of the return springs 48 and 49. Thereby, the contact between the plates 42 and 43 is cut off, and the plates 42 and 43 can freely rotate with each other. Therefore, in this case, the starting clutch 29 is released, and the transmission of rotation from the driven gear 28 to the counter shaft 27 is not performed.
[0022]
As a situation in which the start clutch 29 is used, first, there is a case where the engine 1 starts moving from a stopped state. When starting with the electric motor 2, an output can be obtained even from a stopped state, so that the electric motor 2 can start even when the electric motor 2 is directly connected to the wheels. However, in the case of the engine 1, the electric motor 2 is rotating. Otherwise, no output can be obtained, so even if an attempt is made to start while the engine 1 is directly connected to the wheels, the engine 1 cannot rotate and an engine stall will occur.
[0023]
Therefore, when starting with the engine 1, first, the starting clutch 29 is released to put the engine 1 in an idling state, and then the starting clutch 29 is gradually connected to gradually rotate the engine 1. It is transmitted to the wheels. As described above, when the vehicle is started by the engine 1, for example, when the remaining amount of the battery is insufficient due to traffic congestion and the output of the electric motor 2 is reduced, or when a problem occurs in the electric motor 2, the electric motor 2 is used. It is assumed that the vehicle cannot start.
[0024]
As a situation in which the start clutch 29 is released, the battery may be charged when the vehicle is stopped. When charging the battery, either the clutch 15 or the brake 14 of the forward / reverse switching mechanism 4 is connected to connect the engine 1 to the electric motor 2, and the engine 1 rotates the rotor 7 of the electric motor 2. This is performed by causing the electric motor 2 to function as a generator. However, since the output shaft 5 of the electric motor 2 and the input shaft (output shaft of the engine) 6 of the continuously variable transmission mechanism 20 are connected via the carrier 12, when the electric motor 2 is rotated, the continuously variable transmission mechanism 20 is rotated. The rotation is transmitted to.
[0025]
Therefore, when the battery is charged by the rotation of the engine 1 when the vehicle is stopped, the starting clutch 29 is released, the transmission of rotation from the driven gear 28 to the counter shaft 27 is cut off, and the rotation is not transmitted to the wheels. Keeps the vehicle stationary.
When the starting clutch 29 is connected and the rotation inputted to the driven gear 28 is transmitted to the counter shaft 27, the rotation is output from a differential output gear 30 provided coaxially with the counter shaft 27 to a ring gear 32 of a front differential 31. It is supposed to be. The differential output gear 30 has a smaller diameter than the ring gear 32, and the rotation is further reduced when the rotation is transmitted from the differential output gear 30 to the ring gear 32.
[0026]
The rotation input to the ring gear 32 is distributed to the left and right axle shafts 33 and 34 in the front differential 31 and transmitted to the left and right wheels via the axle shafts 33 and 34. .
Further, a parking gear 35 is fixedly provided on the engine 1 side of the start shaft 29 of the counter shaft 27. A sprag 36 is provided near the parking gear 35. When parking (P range) is selected by the select lever, the sprag 36 is engaged with the parking gear 35 to rotate the parking gear 35. It is being restrained. Therefore, when rotation is input from the wheel side when the vehicle is stopped, the rotation is received by the parking gear 35.
[0027]
Since the belt-type continuously variable transmission as one embodiment of the present invention is configured as described above, when starting (forwarding) using the output of the engine 1, first, the clutch in the forward / reverse switching mechanism 4. 15 and release the brake 14 so that the rotation of the engine 1 can be output to the continuously variable transmission mechanism 20 and the starting clutch 29 is released. That is, the hydraulic pressure is released from the hydraulic chambers 46 and 47 to return the pistons 44 and 45 to the initial positions, and the contact between the drive plate 42 provided on the driven gear 28 and the driven plate 43 provided on the counter shaft 27 is cut off. Thus, the transmission of rotation from the driven gear 28 to the counter shaft 27 is cut off, and the load at the time of starting the engine 1 is reduced.
[0028]
Then, when the engine 1 starts and enters an idling state, the drive plate 42 and the driven plate 43 are brought into contact with each other by gradually increasing the hydraulic pressure in the hydraulic chambers 46 and 47, and the starting clutch 29 is gradually moved. Connect to. At this time, before the start clutch 29 comes into contact, the inertial system from the engine 1 to the driven gear 28 is rotating at a constant speed, whereas the inertial system from the counter shaft 27 to the wheels is stationary. Therefore, there is a rotational speed difference between the drive plate 42 and the driven plate 43 of the starting clutch 29.
[0029]
For this reason, when connecting the starting clutch 29, it is necessary to absorb energy according to the differential rotation speed. However, if the clutch capacity is insufficient for the absorbed energy, the durability life of the starting clutch 29 is extended. There is a risk of lowering. Therefore, in order to ensure sufficient durability of the starting clutch 29, it is necessary to reduce the absorbed energy or to secure a sufficient clutch capacity in the starting clutch 29.
[0030]
First, in order to reduce the absorbed energy, it is necessary to keep the differential rotation speed low. In this regard, in the present belt-type continuously variable transmission, the differential clutch speed is reduced by providing the starting clutch 29 on the counter shaft 27 instead of on the secondary shaft 25 as in the related art. That is, when the rotational speeds of the secondary shaft 25 and the counter shaft 27 are compared, the driven gear 28 has a larger diameter than the drive gear 26, so that when the rotation is transmitted from the drive gear 26 to the driven gear 28, the speed is reduced. The rotation speed of the counter shaft 27 is lower than that of the secondary shaft 25. Therefore, the differential rotation speed can be suppressed to be lower by the reduction ratio between the drive gear 26 and the driven gear 28 than when provided on the secondary shaft 25 as in the related art, and the absorbed energy can be reduced.
[0031]
Next, in order to increase the clutch capacity, it is necessary to increase the number of the plates 42, 43 or to increase the diameter of the plates 42, 43. However, when the number of plates 42 and 43 is increased, the starting clutch 29 becomes longer in the axial direction, and naturally, the countershaft 27 having the starting clutch 29 also becomes longer, and the overall length of the transmission 3 becomes longer. .
[0032]
In this regard, in the present belt-type continuously variable transmission, the starting clutch 29 is disposed in a portion of the countershaft 27 on the engine 1 side where a sufficient outer space is easily secured, so that the plates 42 and 43 are larger than before. The diameter can be increased, and a sufficient clutch capacity is secured by increasing the diameter of the plates 42, 43. That is, when the start clutch 29 is provided on the secondary shaft 25 as in the conventional case, the start clutch 29 and the electric motor 2 interfere with each other, and it is difficult to increase the diameter of the start clutch 29. On the other hand, when the starting clutch 29 is provided on the counter shaft 27 as in the present belt-type continuously variable transmission, there is no interference with the electric motor 2 and the driven pulley 22 Since the starting clutch 29 is provided on the opposite side, there is no interference with the movable sheave 22b of the secondary pulley 22. Therefore, the diameter of the plates 42 and 43 can be increased without considering interference with the electric motor 2 and the movable sheave 22b, and a sufficient clutch capacity can be secured.
[0033]
Further, when the starting clutch 29 is released when the vehicle is stopped, for example, when the battery is charged when the vehicle is stopped as described above, the engagement between the driven gear 28 and the counter shaft 27 is disconnected. The drive system downstream from the counter shaft 27 can freely rotate without being restricted by the engine 1 or the electric motor 2. Therefore, when there is no restraining means, the vehicle starts to move when an external force acts.
[0034]
On the other hand, in the present belt-type continuously variable transmission, the parking gear 35 is provided on the counter shaft 27, and when the select lever is set to the P range, the sprag 36 is engaged with the parking gear 35, and The rotation of the shaft 27 is restricted. Therefore, the vehicle can be reliably stopped regardless of the connection state of the starting clutch 29.
[0035]
Further, when the diameter of the parking gear 35 is small, the force that the parking gear 35 should receive when an external force acts on the vehicle increases, and the durability of the parking gear 35 may decrease. Therefore, it is desired to increase the diameter of the parking gear 35. However, if the parking gear is provided on the secondary shaft together with the starting clutch as in the related art, it is limited to increase the diameter due to interference with the motor and the pulley. There is. On the other hand, in the case of the present belt-type continuously variable transmission, the parking gear 35 is also installed on the counter shaft 27 together with the starting clutch 29, and is further installed on the engine 1 side than the starting clutch 29. There is no need to consider interference with the second and second pulleys 22, and the diameter of the parking gear 35 can be increased.
[0036]
As described above, according to the belt-type continuously variable transmission, since the starting clutch 29 is provided on the counter shaft 27, the speed reduction between the drive gear 26 and the driven gear 28 is smaller than that of the conventional type provided on the secondary shaft 25. There is an advantage that the differential rotation speed can be reduced by the ratio and the durability of the starting clutch 29 can be improved.
[0037]
Further, since the starting clutch 29 is provided on the counter shaft 27, the starting clutch 29 and the electric motor 2 do not interfere with each other, and are further disposed on the opposite side of the driven gear 28 from the secondary pulley 22. Therefore, there is no interference with the movable sheave 22b of the secondary pulley 22. Therefore, the diameters of the plates 42 and 43 of the starting clutch 29 can be increased without considering interference with the electric motor 2 and the movable sheave 22b, and there is an advantage that a sufficient clutch capacity can be secured.
[0038]
It should be noted that the present invention is not limited to the above-described embodiment, and can be implemented with various modifications without departing from the spirit of the present invention. For example, in the above-described embodiment, a case has been described in which the present belt-type continuously variable transmission is applied to a hybrid vehicle in which an engine and an electric motor are combined. However, the present invention can be applied to a normal engine vehicle.
[0039]
【The invention's effect】
As described in detail above, according to the belt-type continuously variable transmission of the present invention, since the starting clutch is provided on the counter shaft, the distance between the drive gear and the driven gear is smaller than that provided on the secondary shaft as in the related art. , The differential rotation speed can be kept low by the reduction ratio, and the durability of the starting clutch can be improved.
[0040]
In addition, since the starting clutch is provided on the counter shaft, even when the electric motor is provided on the primary shaft, the starting clutch and the electric motor do not interfere with each other, and the driven gear is on the side opposite to the secondary pulley. , It does not interfere with the secondary pulley. Therefore, there is an advantage that the diameter of the plate of the starting clutch can be increased without considering interference with the electric motor or the secondary pulley, and a sufficient clutch capacity can be secured.
[Brief description of the drawings]
FIG. 1 is a skeleton diagram showing a configuration of a belt-type continuously variable transmission as one embodiment of the present invention.
FIG. 2 is a side sectional view of a main part of a belt-type continuously variable transmission as one embodiment of the present invention.
FIG. 3 is a side sectional view showing a configuration of a conventional belt-type continuously variable transmission.
[Explanation of symbols]
1 engine 2 electric motor 3 transmission (belt type continuously variable transmission)
4 Forward / reverse switching mechanism 20 Continuously variable transmission mechanism 21 Primary pulley 21a Fixed sheave 21b Movable sheave 22 Secondary pulley 22a Fixed sheave 22b Movable sheave 23 Belt 24 Primary shaft 25 Secondary shaft 26 Drive gear 27 Counter shaft 28 Driven gear 29 Start clutch 30 Diff Output gear 35 Parking brake

Claims (4)

A primary shaft connected to an output shaft of the engine, a primary pulley provided on the primary shaft, a secondary shaft provided side by side with the primary shaft, a secondary pulley provided on the secondary shaft, A belt wound around the pulley and the secondary pulley, a drive gear provided on the engine side of the secondary shaft with respect to the secondary pulley, and a driving force transmitted to driving wheels arranged in parallel with the secondary shaft. And a driven gear provided on the countershaft and meshing with the drive gear. The groove width of the primary pulley and the groove width of the secondary pulley are changed in conjunction with each other to change the primary shaft from the primary shaft. Transmission to the secondary shaft via the belt With the speed of the rotating continuously variable being, in a belt type continuously variable transmission which transmits from the secondary shaft rotation in the counter shaft via the said drive gear and said driven gear,
On said counter shaft, characterized in that it includes a starting clutch for performing connection disconnection between disposed on the engine side the driven gear and the counter shaft than said driven gear, a belt type continuously variable transmission. The belt type motor according to claim 1, wherein an electric motor capable of outputting power to the primary shaft is disposed coaxially between an output shaft of the engine and a rotation shaft of the primary pulley. Step transmission. 3. The belt type motor according to claim 1, wherein the drive gear and the driven gear are configured to reduce speed when transmitting rotation from the secondary shaft to the counter shaft. Step transmission. An output gear provided on the counter shaft for outputting the driving force is disposed on the opposite side of the driven gear from the engine.
The belt-type continuously variable transmission according to any one of claims 1 to 3, wherein:

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