JP2722210B2 - Continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Industrial applications]

The present invention relates to a belt-type continuously variable transmission for a vehicle, and more particularly, to a configuration of a gear-type switching unit that is directly connected to move forward from a neutral position or reversely transmits power to move backward.

[Prior art]

In a continuously variable transmission with a variable pulley using a belt, the pulley ratio is converted according to the relationship between the engine speed and the vehicle speed due to the depression of an accelerator pedal, so that a stepless speed change is automatically performed. . Therefore, in such a continuously variable transmission, there is no need for a speed change mechanism for selectively obtaining a plurality of speeds having different speed ratios, particularly at the forward position, and a neutral position for interrupting the transmission of power is directly connected to directly transmit the power. Forward position,
In addition, only three positions of the reverse position for transmitting power in the reverse direction are required, and a switching unit for switching to these three positions is provided. Therefore, conventionally, there is a switching unit of this type of continuously variable transmission disclosed in Japanese Patent Application Laid-Open No. Sho 60-164061. Here, power is transmitted to the switching unit of the continuously variable transmission via an electromagnetic clutch. In such a system, even if the inertia mass on the engaged side of the switching unit is large, a synchronization mechanism is used for the switching operation for the forward gear and the reverse gear so that synchronization can be smoothly achieved.

[Problems to be solved by the invention]

In such a continuously variable transmission, a newly raised problem is that it is necessary to cope with an increase in the speed of the engine and a high reduction ratio seen in a mini vehicle or the like. In the above-described continuously variable transmission, when the peripheral speed of the belt increases, a large tensile force is generated due to the centrifugal force applied to the belt, which adversely affects the strength, durability, and transmission efficiency of the belt. Therefore, the present invention has a simple configuration in which only a pair of gears is incorporated into the switching portion of the above-described continuously variable transmission, and suppresses a rise in rotation of the main pulley on the input side and suppresses a centrifugal force acting on the belt. Accordingly, it is an object of the present invention to provide a continuously variable transmission capable of coping with an increase in the speed of an engine and an increase in a reduction ratio without adversely affecting the strength, durability, transmission efficiency, and the like of the belt.

[Means for Solving the Problems]

For this reason, in the present invention, the switching unit disposed on the input side of the pulley ratio conversion unit has an input-side shaft and an output-side shaft disposed coaxially with the input-side shaft, and is integrally formed with the input-side shaft. A drive gear and a driven gear rotatably fitted to the output side shaft are meshed with each other via a counter gear and an idler gear, and the intermediate gear that is rotatable coaxially with the input side shaft is connected to the counter gear. And a forward synchronizing mechanism is provided between the output shaft and the intermediate gear, and a reverse synchronizing mechanism is provided between the driven gear and the intermediate gear. The first stage deceleration is performed with the eight gear.

[Action]

Therefore, even if the speed of the engine is increased, the first-stage deceleration is achieved in the switching unit before entering the pulley ratio conversion unit, so that an increase in the centrifugal force applied to the belt can be suppressed, and the strength and durability of the belt can be reduced. In this way, it is possible to avoid a bad influence on the transmission and transmission efficiency, and to cope with a high reduction ratio together with the reduction portion after the pulley ratio conversion portion. Further, the switching portion may be simply added by adding a pair of gears.

【Example】

Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings. 1, a continuously variable transmission with an electromagnetic powder type clutch will be described as an example of a continuously variable transmission to which the present invention is applied. Reference numeral 1 denotes an electromagnetic powder type clutch, 2 denotes a continuously variable transmission, and FIG. The step transmission 2 is roughly divided into a transmission unit 3, a pulley ratio conversion unit 4, and a final reduction unit 5 that are configured to transmit power from the input side, and further include a hydraulic control unit 6 that controls the pulley ratio conversion unit 4. Then, the electromagnetic powder type clutch 1 is housed and installed in one clutch housing 7 divided into three parts,
The switching unit 3, the pulley ratio conversion unit 4, and the final reduction unit 5 of the continuously variable transmission 2 are assembled in a main case 8 and a side case 9 which are continuously joined to the housing 7. The electromagnetic powder type clutch 1 has a crankshaft 10 from the engine.
A ring-shaped drive member 12 serving also as a flywheel is integrally connected to the drive shaft 11 via a drive plate 11, while a disk-shaped driven member 15 having a coil 14 built in the transmission input shaft 13 is integrally formed in the rotation direction. To the spline. The drive and the driven members 12, 15 are loosely fitted to form a circular band-like gap 16 having a large diameter therebetween, and a powder chamber 17 having electromagnetic powder is provided near the gap 16. Further, at the hub portion of the driven member 15 including the coil 14, the slip ring 18 and the power supply brush 19 are slidably contacted, and a clutch current circuit is formed in the coil 14 from the slip ring 18 and further through the driven member 15. I have. In this way, when a clutch current is applied to the coil 14, the magnetic powder generated between the drive and the driven members 12, 15 via the gap 16 causes the magnetic powder to be coupled and accumulated in the gap 16 in a chain-like manner. Member 12
In contrast, the driven member 15 is integrally connected while sliding, and the clutch is connected. On the other hand, when the clutch current is cut, the drive and driven members 12,1
The coupling force of 5 disappears and the clutch is disconnected. In this case, if the supply and cut of the clutch current are performed in conjunction with the operation of the switching unit 3 of the continuously variable transmission 2, the forward D (drive) from the P (parking) or N (neutral) range. , L (low) or retreat R
When switching to the (reverse) range, the clutch 1 is automatically disengaged and the clutch pedal operation becomes unnecessary. Next, the switching unit 3 has a synchronizing mechanism for forward and backward movement, and is provided between a shaft 13 on the input side from the clutch 1 and a main shaft 20 on the output side disposed coaxially therewith. That is, the drive gear 21 is formed integrally with the input side shaft 13,
The output side main shaft 20 has a driven gear 22 on the reverse wave engagement side.
Are rotatably fitted. The drive gear 21 includes:
The intermediate gear 21x on the forward engaged side is rotatably fitted via a bearing. And the shaft 13
A counter gear 24a meshed with the drive gear 21 is spline-fitted to a counter shaft 23 arranged in parallel with the main shaft 20, and a counter gear 24b meshed with the intermediate gear 21x is provided. It is formed integrally. And, by appropriately setting the gear ratio of each of the gears 21, 24a, 24b, 21x, the rotation of the intermediate gear 21x is configured to be reduced with respect to the rotation of the shaft 13, and One-step deceleration is performed. Further, another counter gear 24c is formed integrally with the counter shaft 23, and meshes with an idler gear 26. The idler gear 26 is meshed with the driven gear 22. And the spindle 20 and the intermediate gear 21x
, And a reverse-side synchronization mechanism 28 is provided between the main shaft 20 and the driven gear 22. The pulley ratio conversion unit 4 has a sub shaft 35 disposed in parallel with the main shaft 20, a main pulley 36 and a sub pulley 37 provided on both shafts 20 and 35, respectively, and an endless pulley 36 between the pulleys 36 and 37. Drive belt 38 is stretched. Each of the pulleys 36 and 37 is configured to be divided into two, and one of the pulley halves 36a and 37a
On the other hand, the other pulley half 36b, 37b is made movable to make the pulley interval variable, and the movable side pulley half 36b, 37b is provided with hydraulic servo devices 38, 39 which also serve as pistons themselves, Further, a spring 40 is urged on the movable pulley half body 37b of the sub pulley 37 so as to reduce the pulley interval. Then, while changing the servo hydraulic pressure of the sub-pulley side hydraulic servo device 39, oil is supplied to and discharged from the main pulley-side hydraulic servo device 38, and as one of the pulley intervals between the main pulley 36 and the sub-pulley 37 becomes narrower, The pulley ratio of the pulleys 36 and 37 of the drive belt 38 is changed in a stepless manner so that the power continuously variable is taken out to the sub shaft 35. The final reduction section 5 has a very small high-speed step side pulley ratio of the pulley ratio conversion section 4 of, for example, 0.5.
In consideration of the high rotation speed of the
An output shaft 42 is connected via 41. And this output shaft
A final gear 44 meshes with an output gear 43 of 42, and the axles 46, 4 of right and left driving theory from the final gear via a differential mechanism 45.
The transmission is configured as 7 and can be applied to FF or RR vehicles. Further, the hydraulic control unit 6 is provided with an oil pump 50 as an operation source next to the main pulley 36.
Reference numeral 50 denotes a high-pressure gear pump in which a pump drive shaft 51 penetrates through the main pulley 36, the main shaft 20, and the input-side shaft 13 and is directly connected to the engine crankshaft 10. It has become. The oil pressure of the oil pump 50 is guided to a hydraulic control circuit 53 by an oil passage 52, and this circuit 53
Is controlled by the vehicle speed, the throttle opening according to the depression of the accelerator, the engine speed, etc., and is supplied to the hydraulic servo devices 38, 39 of the pulley ratio conversion unit 4 by the oil passages 54, 55 to control the continuously variable transmission. It is configured as follows. In FIG. 2, the switching unit 3 will be described in detail.
The forward and backward synchro mechanisms 27 and 28 are partially back-to-back. Therefore, the forward synchro mechanism
27, a spline portion 21a and a cone portion 21b are formed on the gear 21x, and the spline portion is formed on the cone portion 21b.
A synchro ring 29 having 29a is fitted. A sleeve 31 is spline-fitted to the hub 30 integrally coupled to the main shaft 20 so as to be movable in the axial direction. A synchro key 32 is inserted into a key groove 30a of the hub 30, and the synchro key 32 is projected by a spring 33. 32a is fitted in the groove 31a of the sleeve 31 so as to be able to move in and out, and a shift fork (not shown) is engaged with the groove 31b outside the sleeve 31. The reverse-side synchro mechanism 28 has the same spline portion 22a and cone portion 22b as described above in the gear 22, and the synchro ring 34 having the spline portion 34a in the cone portion 22b is fitted to the hub 30, the synchro key 32 A synchronizing mechanism is constituted together with the sleeve 31. Here, both ends of the synchro key 32 are fitted in the grooves 29b and 34b of the synchro rings 29 and 34, but the groove width of the grooves 29b and 34b is formed larger than that of the synchro key 32, and the sleeve Synchro ring 2 for 31
9,34 can rotate independently. The operation of the switching unit 3 of the continuously variable transmission 2 configured as described above will be described with reference to FIG. First, the operation of switching to forward movement will be described. Sleeve from the middle position as shown in Fig. 2
Intermediate gear 21 with shift fork 31
Move to X side. Then, the sync key 32 moves with the sleeve 31 and the sync key 32 is
Is pressed against the cone portion 21b of the gear 21X, so that the synchro ring 29 is rotated by the rotation of the intermediate gear 21X and rotates by the difference between the width of the key 32 and the groove 29b, and the splice portion 31c of the sleeve 31 is rotated. FIG. 3 (a) shows the chamfered portion of the spline portion 29a of the synchro ring 29.
It is a position opposite as shown. Next, when the sleeve 31 is further pressed, the key 32 is prevented from proceeding by the synchro ring 29, so that the projection 32a of the key 32 and the groove 31a are disengaged, and only the sleeve 31 moves, and the spline portion 31c 3 comes into contact with the spline portion 29a of the synchro ring 29 as shown in FIG. Therefore, the rotation of the intermediate gear 21X is synchronized with the rotation of the main shaft 20 by a component force in the chamfered portion rotating direction of both spline portions. Then, when synchronized, the synchro ring 29 no longer needs to transmit the rotation to the intermediate gear 21x and becomes free in the rotation direction.
The 31 spline portion 31c meshes with and engages with the spline portion 21a of the intermediate gear 21x while pushing the synchro ring 29. Thus, the shaft 13 on the input side from the clutch 1 forms a power transmission path to the main shaft 20 via the drive gear 21, the counter gears 24a and 24b, and the intermediate gear 21x,
With the engagement of the clutch 1, the engine power is input to the pulley ratio converter 4 in the first-stage deceleration state, and the vehicle travels forward. On the other hand, in the case of the switching operation to the reverse, when the sleeve 31 is moved to the gear 22 side opposite to the above, the sleeve 31 and the spline portions 31c and 34a of the synchro ring 34 perform a synchronizing action as described above. Therefore, even when the portion between the driven member 15 having a large mass of the clutch 1 and the shaft 13 on the input side and the gears 21, 24a, 24c, 26, 22 is coasting, it is immediately synchronized with the main shaft 20. Spline part of sleeve 31 and gear 22
It is engaged by the engagement of 31c and 22a. In this manner, the input shaft 13 is connected to the main shaft 20 via the gears 21, 24a, 24c, 26, and 22, and the engine power is transmitted in a reduced and reversed manner, so that the vehicle travels backward. In the above embodiment, since the first stage is reduced by the switching unit, the number of reduction stages in the final reduction unit 5 is reduced by one, specifically, the intermediate reduction gear 41 is deleted to simplify the configuration. Can be Even in this case, the first-stage deceleration function works effectively in order to suppress an increase in the rotation speed of the pulley ratio conversion unit 4 accompanying an increase in the speed of the engine.

【The invention's effect】

As described in detail above, the present invention has a simple configuration in which only a pair of gears is incorporated in the switching portion of the above-described continuously variable transmission, and suppresses the centrifugal force acting on the belt by the first-stage deceleration. In addition, it is possible to cope with an increase in the speed of the engine and an increase in the speed reduction ratio without adversely affecting the strength, durability, transmission efficiency, and the like of the belt.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram showing an embodiment of a continuously variable transmission according to the present invention, FIG. 2 is a sectional view of a main part, and FIGS. 3 (a) to 3 (c) are explanatory views of the operation. 3 ... Switching unit, 4 ... Pulley ratio converter, 13 ... Input side shaft, 20 ... Main shaft, 21 ... Drive gear, 21x ... Intermediate gear, 22 ... Driven gear, 24a to 24c ...
... Counter gear, 26 ... Idler gear, 27,28 ... Synchro mechanism.

Claims (1)

(57) [Claims] A switching section disposed on an input side of a pulley ratio conversion section has an input side shaft and an output side shaft disposed coaxially with the input side shaft, and is integrally formed with the input side shaft. A drive gear and a driven gear rotatably fitted to the output side shaft are meshed via a counter gear and an idler gear, and a rotatable intermediate gear coaxially rotatable with the input side shaft is meshed with the counter gear. A forward-side synchronization mechanism is provided between the output shaft and the intermediate gear, and a reverse-side synchronization mechanism is provided between the output gear and the driven gear, and at least the drive gear and the intermediate gear are provided. A continuously variable transmission characterized in that a first-stage deceleration is performed between the first and second stages.