JPH0979334A - Belt type continuously variable transmission - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To make a belt-type continuously variable transmission compact in structure and to be easily mounted on a vehicle. SOLUTION: A hollow input shaft 4 to which a rotational force is transmitted from an engine side of a vehicle through a torque converter 1 and a planetary gear mechanism 5 for switching between forward and backward movements is provided with a second shaft 12 and a second shaft 12 which are parallel to the input shaft 4, respectively. The three shafts 16 are arranged symmetrically, the variable drive pulley 15 and the variable driven pulley 17 are attached to the second shaft 12 and the third shaft 16, respectively, and the endless belt 18 is stretched between the variable pulleys 15 and 17. The output shaft 20 is arranged coaxially with the input shaft 4, and the oil pump 24 is arranged at the tip of the drive shaft 23 that is connected to the engine side and passes through the hollow input shaft 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention applies an endless belt between two variable pulleys and continuously changes the rotational speed between the variable pulley shafts according to the radial position of the endless belt contacting the variable pulleys. The present invention relates to a belt type continuously variable transmission.

[0002]

2. Description of the Related Art A conventional vehicle belt type continuously variable transmission is disclosed in Japanese Patent Application Laid-Open No. 1-283461.
The torque is transmitted from the prime mover to the one variable pulley coaxial with the input shaft through the torque converter and the planetary gear device, and the endless belt is stretched between the variable pulley and the other variable pulley arranged below. In this case, the rotational speed between the variable pulley shafts is continuously changed according to the radial position of the endless belt in contact with each variable pulley. On the side, a space of at least the distance between the two variable pulley shafts plus the radius of the variable pulley is required.Therefore, the outer diameter of the housing that accommodates both variable pulleys must be increased accordingly. Since it is necessary to secure a sufficient ground clearance of the continuously variable transmission, there is a problem that it is not easy to mount the belt type continuously variable transmission on the vehicle.

The oil pump, which serves as a hydraulic power source for controlling the transmission and for lubrication, must always be driven from the engine side during operation of the engine. In the case where the rotational force is transmitted to the coaxial variable pulley via the gear device, an oil pump has to be arranged between the torque converter and the planetary gear device because of its structure, and therefore, the input shaft side The total length tends to be large, and the transmission tends to be large.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to make the structure of a belt type continuously variable transmission compact so that it can be easily mounted on a vehicle.

[0005]

In order to achieve this object, a belt type continuously variable transmission according to the present invention is provided with an input shaft, a first parallel transmission which is arranged in parallel with the input shaft with a space therebetween, and which interlocks with the input shaft. Two shafts, a variable drive pulley attached to the second shaft, a third shaft arranged in parallel with the input shaft and the second shaft at intervals, and a variable driven pulley attached to the third shaft, And an endless belt that is stretched between the variable pulleys.

In this case, the second shaft to which the variable drive pulley is attached and the third shaft to which the variable driven pulley is attached are arranged in parallel with the input shaft at intervals, respectively, and the input shaft, the second shaft and the Since none of the three shafts are coaxially arranged, as compared with the conventional device in which the input shaft and one variable pulley are coaxial, the diameters of both variable pulleys and the distance between the two variable pulley shafts are different from each other. Even if the distances are exactly the same, the entire speed change mechanism including the input shaft can be easily downsized, and therefore, the belt type continuously variable transmission can be made compact.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, each embodiment of the present invention will be described with the same reference numerals being given to the same parts. 1 and 2, the engine output of the vehicle is transmitted as a rotational force to the hollow transmission shaft 3 via the torque converter 1 or the lockup clutch 2, and the hollow input shaft 4 is rotatable coaxially with the transmission shaft 3. The transmission shaft 3 is provided with the sun gear 6 of the planetary gear mechanism 5, the planetary gear 7 of the planetary gear mechanism 5 is connected to the input shaft 4, and the wet type for forward movement is provided between the transmission shaft 3 and the planetary gear 7. The clutch 8 is installed, and the reverse wet brake 11 is installed between the ring gear 9 of the planetary gear mechanism 5 and the speed change casing 10.

A second shaft 12 is rotatably arranged parallel to the input shaft 4 at a distance obliquely above the input shaft 4, and a gear 13 of the input shaft 4 and a gear 14 of the second shaft 12 mesh with each other. In addition, the variable drive pulley 15 is attached to the second shaft 12.

On the other hand, a third shaft 16 parallel to the input shaft 4 is rotatably arranged at a symmetrical position of the second shaft 12 about the input shaft 4, and a variable driven pulley 17 is attached to the third shaft 16. An endless belt 18 is hung between the variable drive pulley 15 and the variable driven pulley 17, and as is well known, a continuously variable transmission mechanism 19 is formed by the variable drive pulley 15, the variable driven pulley 17, and the endless belt 18. Endless belt 18 in contact with drive pulley 15 and variable driven pulley 17
In accordance with the radial position of, the rotational force is continuously stepped from the variable drive pulley 15 to the variable driven pulley 17 and transmitted.

Further, the output shaft 20 is rotatably arranged coaxially with the input shaft 4, and the gear 21 of the third shaft 16 and the gear 22 of the output shaft 20 mesh with each other. On the other hand, the drive shaft 23 extending from the engine side is rotatably inserted into the hollow transmission shaft 3 and the hollow input shaft 4, and the oil pump 24 is attached to the tip of the drive shaft 23 protruding from the input shaft 4 into the speed change casing 10. Are arranged.

The speed change casing 10 houses a torque converter 1 as a clutch mechanism, a planetary gear mechanism 5 as a forward / reverse switching mechanism, and a continuously variable speed change mechanism 19 as a main speed change mechanism. 1 is accommodated in the first casing portion 101, and the planet gear mechanism 5 is accommodated in the second casing portion 10
2. The portion housing the continuously variable transmission mechanism 19 will be referred to as the third casing portion 103, respectively.

In the above device, the rotational force transmitted to the transmission shaft 3 via the torque converter 1 or the lockup clutch 2 is directly transmitted to the input shaft 4 by connecting the forward wet clutch 8 to the gear 13 The rotational force transmitted from the input shaft 4 to the second shaft 12 by the gears 14, 14 is transmitted by the continuously variable transmission mechanism 19 to the third shaft 16, and is transmitted from the third shaft 16 to the output shaft 20 by the gears 21 and 22. It is transmitted as forward rotational force.

The torque transmitted to the transmission shaft 3 through the torque converter 1 is disengaged from the forward wet clutch 8 and the reverse wet brake 11 is operated,
The rotational force decelerated in the reverse direction is transmitted to the input shaft 4, and the rotational force transmitted from the input shaft 4 to the second shaft 12 by the gears 13 and 14 is transmitted by the continuously variable transmission mechanism 19 to the third shaft 16,
By the gears 21 and 22, the reverse rotational force is transmitted from the third shaft 16 to the output shaft 20.

In this case, since the second shaft 12 and the third shaft 16 are arranged diagonally above the input shaft 4, which is a symmetrical position, the variable drive pulleys are respectively arranged on the second shaft 12 and the third shaft 16. 15 and the variable driven pulley 17 are attached, the variable pulleys 15,
The maximum distance to the outer peripheral edge is the distance from the input shaft 4 to the second shaft 12 or the third shaft 16 plus the radius of each of the variable pulleys 15 and 17, which is the same as the conventional device. Compared with the length obtained by adding the radius of the variable pulley to the inter-distance, the maximum distance can be easily reduced to be compact, so that the outer diameter of the third casing 103 for housing the continuously variable transmission mechanism 19 is the same as the above. It is inevitably smaller than the case of the conventional device, and there is an advantage that mounting on a vehicle is relatively easy.

The immersion of the continuously variable transmission mechanism 19 in the oil surface accumulated in the lower portion of the speed change casing 10 means that the endless belt 18 is provided on the oil surface of the variable pulley 15 and 17 in addition to the variable pulleys 15 and 17. Will be soaked, both variable pulley 15,
17 and the endless belt 18 vigorously agitate the oil surface, which causes problems such as output loss due to driving resistance of the variable pulleys 15 and 17 and the endless belt 18 and an increase in oil temperature, which is not preferable. Since the continuously variable transmission mechanism 19 is symmetrically arranged above the input shaft 4 and the output shaft 20, the endless belt 18 of the continuously variable transmission mechanism 19 does not particularly soak into the oil surface and agitate the oil surface. .

Therefore, the oil level of the oil sump at the bottom of the third casing 103 can be increased,
The vertical gap between the gears 13 and 22 and the bottom of the third casing portion 103 can be reduced, and the vertical cross-sectional area of the third casing portion 103 whose axial longitudinal cross section is substantially triangular is minimized to make Since the third casing portion 103 can be partially downsized, it is relatively easy to mount the third casing portion 103 on the vehicle, and the ground clearance of the portion mounted on the vehicle can be increased. There are also advantages.

Further, the drive shaft 23 extends from the engine side so as to pass through the hollow transmission shaft 3 and the hollow input shaft 4,
Drive shaft 2 protruding from input shaft 4 into speed change casing 10
Since the oil pump 24 is arranged at the tip of the oil pump 3, and the continuously variable transmission mechanism 19 is arranged above the input shaft 4, the oil pump 24 is formed in the space immediately below the continuously variable transmission mechanism 19. It is not necessary to provide an axial space for installing the oil pump 24, for example, between the torque converter 1 and the planetary gear mechanism 5, and the oil pump 24 does not need to be provided.
Since it is installed inside, the oil pump is placed outside the speed change casing to reduce the space restrictions related to vehicle mounting or restrictions from other loads compared to the case where the total length of the speed change casing is reduced. You can let
It is particularly suitable as a belt type continuously variable transmission for vehicles.

Next, in the embodiment shown in FIG. 3, the second shaft 12 is arranged with respect to the output shaft 20 arranged coaxially with the input shaft 4.
The third shaft 16 and the third shaft 16 are arranged obliquely downwardly and in parallel with the output shaft 20, and are rotatably arranged so as to be symmetrical about the output shaft 20.
The endless belt 18 is stretched between the variable drive pulley 15 attached to the No. 2 and the variable driven pulley 17 attached to the third shaft 16 to form the continuously variable transmission mechanism 19.
Further, similarly to the above-described embodiment, the oil pump 24 is arranged at the tip of the drive shaft 23 that is inserted from the engine side through the hollow transmission shaft and the hollow input shaft 4 and projects from the input shaft 4 into the speed change casing 10. Has been done.

Also in this belt type continuously variable transmission, similar to the above-mentioned embodiment, there is an oil sump at the bottom of the third casing portion 103, but the variable pulleys 15 and 17 and the bottom portion of the third casing portion 103 are provided. And the variable pulleys 15 and 17 and the endless belt 18 are prevented from being immersed in the oil surface, while a space above the third casing portion 103 is provided during mounting on a vehicle. When required, the axial lengthwise cross section of the third casing portion 103 is downsized into a substantially triangular shape to reduce the size of the first casing portion 1.
01 and the second casing portion 102, the third casing portion 103 is compactly arranged downward, and therefore, there is an advantage that the mounting is easy.

Further, in this embodiment, similarly to the above-mentioned embodiment, the maximum distance from the output shaft 20 to the outer peripheral edges of the variable pulleys 15 and 17 can be easily made smaller than in the case of the above-mentioned conventional device, so that there is no step. The outer diameter of the third casing portion 103 for accommodating the speed change mechanism 19 can also be made small, and there is an advantage that mounting on a vehicle is relatively easy. It can be arranged in the space formed directly above, and it is not necessary to particularly provide an axial space for installing the oil pump 24. Therefore, not only can the oil pump 24 be installed in the speed change casing 10, Since it is not necessary to increase the total length of the transmission casing 10 by installing the oil pump 24,
It is suitable as a belt type continuously variable transmission for vehicles.

In each of the above-described embodiments, the second parallel shaft and the third parallel shaft to which the variable pulleys are respectively attached.
The shafts are arranged substantially horizontally to the left and right of the input shaft. If necessary, the plane including the parallel second shaft and the third shaft is inclined from the horizontal direction, or the parallel second shaft and It is also possible to displace the third shaft vertically from the input shaft in the horizontal direction, or to dispose the second shaft and the third shaft asymmetrically with respect to the input shaft, or alternatively, to dispose the input shaft and the output shaft. Even if the axial center with respect to the shaft is appropriately shifted, and further, the above-mentioned modified examples are appropriately combined, the same operational effects as those of the above-described respective embodiment examples can be obtained.

[0022]

In the belt type continuously variable transmission according to the present invention, the second shaft to which the variable drive pulley is mounted and the third shaft to which the variable driven pulley is mounted are parallel to the input shaft at intervals. Are arranged, the input shaft and the second shaft and the third
Since none of the shafts are arranged on the same axis, the entire transmission mechanism including the input shaft can be easily made small, so that the belt type continuously variable transmission can be constructed compactly, and especially in the vehicle. Great advantage for use.

[Brief description of drawings]

FIG. 1 is a schematic top view in an embodiment of the present invention.

FIG. 2 is a rear view of the main part of the embodiment described above.

FIG. 3 is a rear view of a main part according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 torque converter 3 transmission shaft 4 input shaft 5 planetary gear mechanism 8 forward wet clutch 10 speed change casing 11 reverse drive wet brake 12 second shaft 15 variable drive pulley 16 third shaft 17 variable driven pulley 18 endless belt 19 continuously variable transmission mechanism 20 Output shaft 23 Drive shaft 24 Oil pump

Claims (7)

[Claims] 1. An input shaft, a second shaft arranged in parallel with the input shaft at a distance from the input shaft and interlocking with the input shaft by a gear train, a variable drive pulley attached to the second shaft, the input shaft and the above-mentioned. A belt-type continuously variable transmission having a third shaft arranged in parallel with the second shaft at a distance from each other, a variable driven pulley attached to the third shaft, and an endless belt stretched between the variable pulleys. Machine. 2. The belt type continuously variable transmission according to claim 1, wherein the second shaft and the third shaft are arranged above or below the input shaft. 3. The belt type continuously variable transmission according to claim 1, wherein the second shaft and the third shaft are arranged substantially symmetrically with respect to the input shaft. 4. The belt type according to any one of claims 1 to 3, further comprising a casing that accommodates the whole, and a portion of the casing that accommodates both the variable pulleys has a substantially triangular longitudinal cross section. Continuously variable transmission. 5. The drive shaft according to any one of claims 1 to 4, wherein the input shaft is formed hollow, is connected to the engine side, and is rotatably inserted in the input shaft, and the input shaft. Belt type continuously variable transmission having an oil pump arranged at the tip of the drive shaft protruding from the drive shaft. 6. The belt type continuously variable transmission according to claim 5, wherein the oil pump is arranged in a casing. 7. The rotational force is transmitted from the engine side to the input shaft via a torque converter or a lockup clutch and a planetary gear mechanism as a forward / reverse switching mechanism from any one of claims 1 to 6. Belt type continuously variable transmission.