JP2002327828A - Continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact and lightweight continuously variable transmission providing a triaxial structure by a simple forward/reverse change-over device and improving transmission efficiency. SOLUTION: The forward/reverse change-over device 3 clamps a forward brake B and releases a reverse clutch C in a forward range. In this state, rotation of an input shaft 12 is outputted as a reverse and decelerating rotation to a ring gear R by fixation of a carrier CR and a primary pulley 9 is rotated. Accordingly, a reverse and decelerating rotation of the primary pulley 9 composing a first shaft I is suitably changed by a belt type continuously variable transmission 5, the reverse rotation is transmitted to a secondary pulley 10 composing a second shaft II, a normal rotation is transmitted to a differential device 6 by an output gear 15 and a mount ring gear 65, and driving wheels are rotated in a forward direction by right and left drive shafts 16a and 16b. In a reverse range, the reverse clutch C is engaged and the forward brake B is released. In this state, a planetary gear 17 is in a directly coupled state, and the rotation of the input shaft 12 is transmitted as it is to the primary pulley 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a primary pulley and a secondary pulley each comprising a fixed sheave and a movable sheave, a belt wound around both of these pulleys (including a belt made of a metal bending link), and the like. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuously variable transmission (CVT) provided with a forward / reverse switching device, and more particularly to a continuously variable transmission suitable for use as an automobile transmission.

[0002]

2. Description of the Related Art Generally, the above-mentioned belt type continuously variable transmission (for example, see Japanese Patent Application Laid-Open No. 10-184834) uses a dual pinion planetary gear as a forward / reverse switching device, and the planetary gear connects a sun gear to an input shaft. At the same time, the carrier is connected to the fixed sheave of the primary pulley, the ring gear is connected to the reverse brake, and a direct clutch is interposed between the sun gear (input shaft) and the carrier.

Accordingly, the forward / reverse switching device transmits the rotation of the input shaft to the primary pulley as forward rotation (rotation in the same direction as the engine) by integrally engaging the direct clutch to rotate the planetary gear integrally. By releasing the direct clutch and engaging the reverse clutch, the rotation of the sun gear is transmitted from the carrier to the primary pulley as reverse rotation (rotation in the opposite direction to the engine).

[0004] Therefore, when the vehicle is moving forward, it is desirable to transmit the rotation in the same direction as the engine rotation direction to the output shaft as a transmission of an automobile. The fourth shaft) is arranged to reverse the rotation of the secondary shaft and transmit the rotation to the differential device, so that the rotation direction of the wheel drive shaft during forward movement matches the rotation direction of the engine.

In addition, since the forward / reverse switching device is in a forward state and is directly connected, it is not possible to obtain a sufficient reduction ratio. Drive torque is secured.

On the other hand, a simple planetary gear and a dual pinion planetary gear are provided as a forward / reverse switching device of a belt-type continuously variable transmission, and both planetary gears are:
There has been proposed one in which a sun gear is connected to an input shaft, a ring gear is connected to a primary pulley, and a carrier is fixed (see Japanese Patent Application Laid-Open No. 61-270542).

In the forward / reverse switching device, when the rotation of the input shaft is transmitted to the sun gear of the simple planetary gear by the switching mechanism, the sun gear and the ring gear rotate in opposite directions, and are transmitted to the wheel drive shaft as forward rotation. When the rotation of the input shaft is transmitted to the sun gear of the dual planetary gear, the sun gear and the ring gear rotate in the same direction, and transmit the reverse rotation to the wheel drive shaft.

[0008]

The former forward / reverse switching device using one dual pinion planetary gear is disclosed in US Pat.
In addition to the primary shaft, secondary shaft, and differential shaft (left and right wheel drive shafts), a total of four countershafts are required, which hinders downsizing, and a reduction gear mechanism is arranged on the countershaft. In addition, a dual planetary gear is required for the forward / reverse switching device, which causes an increase in weight and increases gear meshing, which is not preferable in terms of transmission efficiency.

On the other hand, in the latter forward / reverse switching device using two types of planetary gears, the engine rotation direction and the primary pulley rotation direction are opposite, so that the counter shaft can be omitted and a three-axis structure can be used. Although it is possible to reduce the size, the forward / reverse switching device requires a simple planetary gear, a dual pinion planetary gear, and a switching mechanism for switching the input to the planetary gear, and the forward / reverse switching device becomes large and complicated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a continuously variable transmission which is compact, lightweight and has improved transmission efficiency by enabling a three-axis structure with a simple forward / reverse switching device. .

[0011]

According to a first aspect of the present invention, a case (7) includes a forward / reverse switching device (3), a belt-type continuously variable transmission (5), and a differential device (6). In the continuously variable transmission (1), the forward / reverse switching device (3) has one simple planetary gear (17) and connects the sun gear (S) of the planetary gear to the input side (12). , The ring gear (R) is connected to the output side (19), and the reverse brake (B) capable of locking the carrier (CR), and the three elements (S, R, CR) of the planetary gear (For example, S and C
R) with which a reverse clutch (C) can be connected, a first shaft (I) aligned with a primary pulley (9) of the belt-type continuously variable transmission (5), and a secondary pulley (10). A continuously variable transmission, comprising: a second shaft (II) that is aligned; and a third shaft (III) that is aligned with the left and right drive shafts (16a, 16b) of the differential device (6).

According to a second aspect of the present invention, the forward / reverse switching device (3) is disposed on the first shaft (I) on a transmission upstream side of the primary pulley (9), and the ring gear (R) is provided. Are connected to a fixed sheave (19) of the primary pulley (9), the sun gear (S) is connected to an input shaft (12), and the reverse clutch (C) is connected between the input shaft and the carrier. 2. The method according to claim 1, wherein the step is interposed.
In the continuously variable transmission described above.

According to a third aspect of the present invention, an annular flange (19a) is provided on the back surface of the primary pulley (9), and a bearing (32) is fitted around the outer periphery of the flange to form the case (7). ) And a cavity (3
6), and a ring gear plate (31) fixed to the ring gear (R) is provided in the cavity (19).
The continuously variable transmission according to claim 2, wherein a sun gear disk (30) formed on the inner peripheral surface of (a) and forming the sun gear (S) is connected to the input shaft (12).

According to a fourth aspect of the present invention, the ring gear plate (31) has a flange portion (31a) extending in the axial direction toward the primary pulley on the inner diameter side and a stepped portion (31b) at an intermediate portion. And the front sun gear disk (3
The ring gear plate (31) has a flange portion (30a) extending in the axial direction on the primary pulley side on the inner diameter side and a stepped portion (30b) on an intermediate portion.
And both flange portions (31a) (30) of the sun gear disc (30).
b) is coupled to the flange (19a) or the input shaft (12) of the fixed sheave so that the two portions partially overlap in the axial direction, and the stepped portions (31b) and (30b) partially overlap in the axial direction. The continuously variable transmission according to claim 3, wherein the transmission is arranged as follows.

According to a fifth aspect of the present invention, the carrier (CR) has a brake hub (25b) extending in the axial direction on the outer diameter side to the opposite side of the primary pulley, and the primary hub on the inner diameter side. A carrier plate (25) having a flange (25a) extending in the axial direction on the pulley side and a clutch hub (25c) extending on the opposite side to the primary pulley at an intermediate portion thereof is provided. The carrier plate (25) is rotatably supported by the input shaft, and the flange (25a) is housed inside the stepped portion (30b) of the sun gear disc (30). Item 4. The continuously variable transmission according to item 4.

According to a sixth aspect of the present invention, the gear ratio (i) between the ring gear (R) and the sun gear (S) is 1.4 to 1.4.
The continuously variable transmission according to any one of claims 1 to 5, wherein the range is 1.5.

[Operation] Based on the above configuration, the forward / reverse switching device (3) engages the forward brake (B) and releases the reverse clutch (C) in the forward (D) range. In this state, rotation of the input side (for example, the input shaft 12) is output to the ring gear (R) as reverse rotation / reduced rotation by fixing the carrier (CR), and the output side (for example, the primary pulley 9) is rotated. Therefore, the first axis I
The reverse rotation and the deceleration rotation of the primary pulley (9) are appropriately shifted by a belt-type continuously variable transmission (5).
The reverse rotation is transmitted to the secondary pulley (10) constituting the second shaft II, and the forward rotation is transmitted to the differential device (6) by the output gear (15) and the mount ring gear (65), etc. (16a, 1
The drive wheel is rotated in the forward direction according to 6b).

In the case of the reverse (R) range, the forward / reverse switching device (3) engages the reverse clutch (C) and releases the forward brake (B). In this state, two of the three elements are connected and the planetary gear (17) is directly connected, and the rotation of the input side (for example, the input shaft 12) is transmitted to the output shaft (for example, the primary pulley 9) as it is. Is done. The forward rotation of the primary pulley (9), which is the first shaft I, is transmitted to the secondary pulley (10), which is the second shaft II, as the same rotation, and further transmitted through the output gear (15) and the ring gear (65). The rotation is transmitted to the differential device (6) as reverse rotation, and the drive wheels are rotated in the reverse direction by the left and right drive shafts (16a, 16b).

The symbols in parentheses are for comparison with the drawings, but do not affect the scope of the claims.

[0020]

According to the first aspect of the present invention, when the forward-reverse switching device is in the forward state, the rotation of the input side is reversed and transmitted to the output side. Although it is used, the first, second and third axes are sufficient, and the conventionally required counter shaft (fourth axis) is not required. Further, the forward / reverse switching device requires only a simple configuration including one simple planetary gear, a forward brake, and a reverse clutch, and together with the fact that the fourth shaft is not required, the continuously variable transmission can be made compact. Can be configured. Further, the fourth shaft becomes unnecessary, and the reduction gear mechanism provided on the fourth shaft is also eliminated. However, when the forward / reverse switching mechanism is in the forward position, a predetermined reduced rotation is output, so that a desired reduction rotation is output. The speed ratio (width) can be ensured, and since there is no speed reduction gear mechanism and simple planetary gears, the number of meshing gears is reduced, transmission efficiency can be improved, and weight can be reduced. .

According to the second aspect of the present invention, since the forward / reverse switching device is disposed on the first shaft upstream of the transmission of the primary pulley, the forward / reverse switching device is axially mounted on the hydraulic actuator of the secondary pulley. A rational arrangement such as lapping is possible, and the compactness of the forward / reverse switching device itself including the simple planetary gears and the like can be combined, so that the continuously variable transmission can be downsized.

According to the third aspect of the present invention, a cavity is provided on the inner diameter side of the flange supporting the fixed sheave of the primary pulley, and a ring gear plate is connected to the inner peripheral surface of the flange in the cavity. By connecting the sun gear disk to the input shaft, the axial size can be further reduced.

According to the fourth aspect of the present invention, the ring gear plate and the sun gear disk are formed with flanges extending in the same direction, and these two flanges partially overlap in the axial direction. Connected to the ring gear plate and the sun gear disk, and further formed with stepped portions at the intermediate portions of the ring gear plate and the sun gear disk, respectively, and these stepped portions are arranged so as to partially overlap in the axial direction. The size can be reduced, and the positioning accuracy of the planetary gears can be improved, so that the transmission efficiency of the gears can be improved.

According to the fifth aspect of the present invention, the brake hub, the clutch hub and the flange are integrally provided on the carrier plate, so that the rational arrangement of the planetary gear, the forward brake and the reverse clutch is simplified. In addition, the carrier plate is rotatably supported on the input shaft by the above-mentioned flange portion, and the carrier is supported by only one carrier plate. The efficiency and reliability can be improved, and the flange portion is housed and arranged on the inner diameter side of the stepped portion of the sun gear disk, so that the carrier is supported by only one carrier plate. Together with this, it is possible to further reduce the size in the axial direction.

According to the present invention, the gear ratio between the ring gear and the sun gear is set to 1.4 to 1.5.
An appropriate gear ratio (width) can be obtained in consideration of the reverse running that is directly connected, and the sun gear has a larger diameter due to the sun gear disk, so the above-described stepped structure of the sun gear disk and the ring gear plate becomes possible. Thus, the size in the axial direction can be reduced.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

The continuously variable transmission (CVT) 1 includes a torque converter 2, a forward / reverse switching device 3, and a belt-type continuously variable transmission 5.
And a differential device 6 and the like, and are housed in a case 7 in which a torque converter housing 7B and a transmission case 7A are integrated. Further, the belt-type transmission 5 includes a primary pulley 9, a secondary pulley 10, and a belt (a rubber belt, a metal push type belt (so-called Bantone type)) wound around these belts, a metal pull type belt, and a metal pull type belt. The primary pulley 9 is aligned with the input shaft 12, the torque converter 2 and the engine crankshaft 13 to form a first shaft I, and the secondary pulley Reference numeral 10 is aligned with the output gear 15 to form a second shaft II, and left and right drive shafts (accel shafts) 16a, 16a of the differential device.
b constitutes a third axis III, these first axis I, second axis II,
The three axes III are arranged in a triangular shape in a side view.

The torque converter 2 includes a pump impeller 2a connected to the engine crankshaft 13, a turbine runner 2b connected to the input shaft 12, and a stator 2c fixed via a one-way clutch 2d. Further, a lock-up clutch 2e for mechanically directly connecting the pump impeller 2a and the turbine runner 2b.
have. Therefore, the engine crankshaft 13
Rotation of the pump impeller 2a, turbine liner 2b,
The power is transmitted to the input shaft 12 through an oil flow passing through the starter 2c or by a mechanical connection by a lock-up clutch 2e.

The forward / reverse switching device 3 has one simple planetary gear 17, the sun gear S of the planetary gear is fixed to the input shaft 12, the ring gear R is fixed to the fixed sheave 19 of the primary pulley 9, and the pinion P is connected to a forward brake B, and a reverse clutch C is provided between the input shaft 12 and the carrier CR.
Is interposed.

More specifically, as shown in FIG. 2, a hydraulic pump 20 is disposed on a case fixing portion 7a between the torque converter 2 and the forward / reverse switching device 3, and the clutch is arranged along the case fixing portion 7a. A drum 21 is arranged, and is fixed to the input shaft 12 at the inner peripheral end of the drum. A piston 22 having a check ball for centrifugal hydraulic pressure discharge is fitted in the clutch drum 21 in an oil-tight manner, and a return spring 23 is housed between the piston and a retainer.

On the other hand, the front side (engine side) of the carrier CR is a disk-shaped plate 25, and the inner diameter side of the carrier plate is a flange 25a extending rearward in the axial direction to form the input shaft 12a. The outer diameter side extends axially forward to form a brake hub 25b. Further, a clutch hub 25c extending forward in the axial direction is fixed to an intermediate portion of the plate 25, and a number of clutch plates and disks are provided between the outer peripheral surface of the clutch hub and the inner peripheral surface of the outer peripheral portion of the clutch drum 21. Constitutes the wet multi-plate clutch C, and the clutch is operated by a hydraulic actuator 26 composed of a cylinder including the piston 23 and a clutch drum.

The brake hub 2 of the case 7
A spline is formed in a portion facing 5b, and a number of brake plates and disks are interposed between the spline and the brake hub to constitute the wet-type multi-disc brake B.
A support 7b is fixed to the case 7 between the forward / reverse switching device 3 and the primary pulley 9, and is integrally fixed to the case. The forward / backward switching device for the support 7b (front) On the side, a cylinder of a hydraulic actuator for brake 27 is formed in a concave shape, and a piston 29 fitted to the cylinder in an oil-tight manner extends toward the brake B and a return spring is interposed.

The sun gear S of the simple planetary gear 17 is formed on the outer peripheral surface of a disk 30 having a crank shape, and the inner diameter portion of the sun gear disk extends rearward in the axial direction to form a flange 30a. The flange 25a of the carrier plate 25 is connected to the input shaft 12 by a spline formed on the inner peripheral surface thereof and is interposed between the input shaft 12 and an intermediate stepped portion 30b extending forward in the axial direction. . The ring gear R has an outer peripheral portion fixed to the rear end surface thereof. The ring gear plate 31 is formed to have an uneven cross section, and an inner diameter portion extends forward in the axial direction to form a flange portion 31a. The outer peripheral surface of the flange is spline-coupled to the inner peripheral surface of the flange 19 a of the fixed sheave 19.
Further, a stepped portion 31b formed at an intermediate portion of the ring gear plate 31 and an intermediate stepped portion 30b of the sun gear disk 30 are arranged so as to partially overlap each other in the axial direction. Is positioned through the thrust needle.

Thus, in the forward / reverse switching device 3, the carrier plate 25, the sun gear disk 30, and the ring gear plate 31 include the inner race and the fixed sheave of the case fixing portion 7 a of the input shaft 12 where the clutch drum 23 is fixed and the bearing 32. Is positioned between the flange 19a and the end face of the flange 19a. The planetary gear 17 has a large diameter with the sun gear S cut on the outer peripheral surface of the disk 30.
The gear ratio i (R / S) between the ring gear R and the sun gear S takes a relatively small value of about 1.4 to 1.5.

On the other hand, the primary pulley 9 has a fixed sheave 19 and a movable sheave 33. The fixed sheave has an annular flange 19a on the forward / reverse switching device side, and the outer peripheral surface of the flange is The ball bearing 32 is interposed between the support portion 7b and the support portion 7b. The inner diameter side of the flange portion 19a is a concave cavity 36, and in the cavity 36,
The flange 31a of the ring gear plate is provided on the inner peripheral surface of the flange.
Are spline-engaged, the flange 30a of the sun gear disk 30 is spline-engaged with the input shaft 12, and both flanges 31a, 30a are arranged so as to partially overlap in the axial direction.

That is, the sun gear S has a large diameter and can be formed on the outer peripheral surface of the disk 30 having a crank shape, and a fixed sheave supporting portion such as a bearing 32 is disposed in a concave portion of the disk 30. In addition to the elimination of the support disk (plate) on the pulley side of the carrier, it is possible to reduce the axial dimension, and furthermore, the support portion such as the bearing 32 is disposed on the outer diameter side. It is possible to form a cavity 36 on its inner diameter side, and to arrange a connecting portion between the ring gear R and the fixed sheave 19 and a connecting portion between the sun gear S and the input shaft 12 to shorten the cavity in the axial direction. The carrier CR is mounted on the plate 25 on the torque converter side.
A relatively wide collar 2
It is securely supported by the input shaft 12 at 5a.

The movable sheave 33 is slidably supported on the shaft portion 19b of the fixed sheave 19 via a ball spline, and a hydraulic actuator 37 for shifting operation is disposed on the back surface thereof. The hydraulic actuator comprises a cylinder comprising a flange 39 formed integrally with a movable sheave 33, and a first piston which is fitted to the cylinder in an oil-tight manner and is integrally fixed to a fixed sheave shaft 19b. 40, a drum-shaped cylinder member 41 sandwiched and fixed to the rear end face of the fixed sheave shaft portion 19b,
And a second piston 42 which is in contact with the tip of the flange 39 and is fitted in the cylinder member 41 in an oil-tight manner. And the first
The first oil chamber 43 formed by the piston 40 and the rear surface of the movable sheave 33 and the second oil chamber 45 formed by the second piston 42 and the cylinder member 41
6, so that the oil holes a,
The hydraulic pressure supplied from b and c acts on the movable sheave 33 with a pressure receiving area approximately twice as large as that of a hydraulic actuator on the secondary side described later.

The tip of the shaft portion 19b of the fixed sheave is rotatably supported by the case 7 by a ball bearing 47 having a high (long in the radial direction) inner race. Together with the support of the ball bearing 32 by the portion 19a, both end portions are supported via the ball bearings 32 and 47.
Further, the input shaft 12 has its rear end portion rotatably supported by the fixed sheave 19 at the cavity 36, and its front side is rotated by the case fixing portion 7a and the stator connecting portion 49 of the torque converter 2. It is freely supported.

On the other hand, the secondary pulley 10 has a movable sheave 5 supported only by a fixed sheave 50 and a shaft portion 50a of the fixed sheave via a ball spline so as to be slidable only.
The hydraulic actuator 52 for holding the belt clamping pressure is disposed on the back of the movable sheave. The hydraulic actuator has a cylinder composed of a flange 53 integrally formed on the back surface of the movable sheave, and a piston 55 fitted to the cylinder in an oil-tight manner and fixed integrally to the shaft 50a. A spring 57 for holding an initial pressure is contracted in an oil chamber 56 formed by the piston and the cylinder. Further, a hydraulic pressure cancel plate 59 is stopped and connected to the tip of the flange 53.

Further, an output gear 15 is spline-coupled to the front side of the fixed sheave shaft portion 50a, and both ends of the shaft portion 50a are roller bearings 61 and 62, respectively.
And is rotatably supported by the case 7 through the second shaft II.

The differential device 6 has a relatively large mount ring gear 65 fixed to a differential case 63. Both ends of the differential case 63 are supported by the case 7 via tapered roller bearings 66 and 67, The drive shaft (askul shaft) 16a, 16b constitutes a third shaft III. The differential case 63 supports a pair of differential pinions 69 composed of a bevel gear with one shaft, and side gears 70 composed of a bevel gear fixed to the left and right drive shafts 16a and 16b supported by the differential case. 70 meshes with the differential pinion. The output gear 15 of the second shaft II meshes with the ring gear 65 of the third shaft III, and the output gear 15 has a relatively small diameter and the ring gear 65 has a relatively large diameter. A large reduction ratio.

Incidentally, in the conventional continuously variable transmission disclosed in Japanese Patent Application Laid-Open No. H10-196749, the case is divided into a torque converter housing, a transmission case, and a rear cover. When assembling such a continuously variable transmission, a brake, a countershaft, and a differential device are assembled in a transmission case, a housing is temporarily assembled, and the transmission case in which the housing is temporarily assembled is turned over, and a primary pulley and a rear pulley are mounted on a rear cover. Attach to the transmission case as an assembly with the secondary pulley attached. Further, the housing is removed, and a forward / reverse switching device including the input shaft is mounted.
As described above, the forward / reverse switching device is inserted after the belt-type continuously variable transmission is mounted. When the rear case assembly is mounted, both the counter gear and the spline connected to the primary pulley of the forward / reverse switching device are fitted. Since it is difficult to insert them so that they match each other, a forward / reverse switching device is attached later. With such a conventional configuration, the above-described assembling method must be performed, and a troublesome operation such as turning over the transmission case, temporarily assembling and removing the housing, and the like is required.

The case 7 of the above-described continuously variable transmission 1 includes a transmission case 7A and a torque converter housing 7B, and has a center support portion (support portion 7b) as a separate body. Therefore, when assembling the continuously variable transmission 1, the primary pulley 9, the secondary pulley 10, and the differential device 6 are assembled to the transmission case 7A,
Attach the center support part (support part 7b),
The forward / reverse switching device 7 is attached, and then the torque converter housing 7B is attached. When the belt-type continuously variable transmission 5 is mounted, since the belt 11 is already hung between the two pulleys 9 and 10, the two pulleys are inclined in a direction approaching by the restoring force of the pulleys, but support the secondary pulley 10. Torque converter housing 7B part 7
e is provided with a taper so that the housing can be attached smoothly. (In the above-mentioned conventional continuously variable transmission, it is fixed firmly to the rear case so as not to shift.) With such an assembling method, the case 7 is turned over and the forward / reverse switching device is attached later. Without any trouble, the case 7 can be attached in order from the side opposite to the engine direction, and the assemblability can be improved.

Next, the operation of the continuously variable transmission 1 having the above configuration will be described. When both the forward brake B and the reverse clutch C are in the released state, the continuously variable transmission 1 is in the neutral (N) state, and the rotation of the engine crankshaft (output shaft) 13 is transmitted via the torque converter 2. Although transmitted to the input shaft 12, since the brake B and the clutch C are in the released state, the sun gear S rotates together with the input shaft 12 and the carrier CR only idles, and the ring gear R, and thus the primary pulley 9, is stopped. It is in.

When the driver operates the shift lever to the forward (D) range, the forward / reverse switching device 3 holds the clutch C in the released state, but switches the forward brake B to the engaged state. That is, hydraulic pressure is supplied to the oil chamber of the hydraulic actuator 27 of the support portion 7b, and the piston 29 is extended to lock the forward brake B.

In this state, the rotation of the sun gear S integral with the input shaft 12 is output from the ring gear R as reverse rotation and reduced rotation by fixing the carrier CR by locking the brake B. At this time, in the planetary gear 17 of the forward / reverse switching device 3, the sun gear S is formed to have a relatively large diameter by the sun gear disc 30, and the gear ratio i with the ring gear R is about 1.4 to 1. As a result, the reduction ratio, which is obtained by dividing the input rotation speed of the planetary gear by the output rotation speed, is about 1.4 to 1.5, and does not result in a large reduction.

The reverse rotation / reduced rotation of the ring gear R is transmitted to the primary pulley 9 via the ring gear plate 31 and further transmitted to the secondary pulley 10 via the belt 11.
Is transmitted as rotation in the same direction as the reverse rotation. On this occasion,
Oil chamber 56 of secondary pulley hydraulic actuator 52
, Line pressure is supplied through oil passages d and e to maintain a belt clamping pressure corresponding to the transmission torque capacity, and hydraulic actuators 37 of the primary pulleys have oil chambers 43 and 45 having a double piston structure. The speed of the belt-type continuously variable transmission 5 is controlled so that the gear ratio is adjusted appropriately according to the vehicle speed, the throttle opening, and the like. Further, the cancel plate 5 is connected to the secondary hydraulic actuator 52 via oil passages a and f.
The above hydraulic pressure is also guided to the cancel chamber 58 inside 9 to cancel the centrifugal hydraulic pressure in the oil chamber 56.

The reverse rotation of the shaft portion 50a of the secondary pulley 10 forming the third shaft III is performed by the forward rotation via the output gear 15 and the mount ring gear 65 (that is, the first rotation of the first shaft composed of the engine crankshaft 13 and the input shaft 12). (Rotation in the same direction as the axis I) to the differential device 6 and the left and right drive shafts (axle shafts) 16a, 1
6b is transmitted as differential rotation to rotate the left and right drive wheels in the forward direction of the wheels. At this time, the output gear 15 and the ring gear 65 have a relatively large reduction ratio, and together with the reduced rotation of the forward / reverse switching device 3, the reduction gear mechanism of the counter shaft conventionally required is omitted. Even if there is a rotation having the desired gear ratio (width),
a, 16b.

On the other hand, the driver moves the shift lever backward (R).
When the operation is performed in the range, the forward brake B is released and the reverse clutch C is engaged. That is, while the pressure oil drains from the oil chamber of the hydraulic actuator 29, the oil pressure is supplied to the oil chamber of the hydraulic actuator 26 including the clutch drum 21, and the reverse clutch C is engaged.

In this state, the clutch drum 21 integrated with the input shaft 12 and the clutch hub 25c fixed to the carrier plate 25 are integrated, so that the sun gear S and the carrier CR are integrated and the planetary gear 17 rotates integrally. I do. Thus, the forward rotation of the input shaft 12 is transmitted to the primary pulley 9 as it is, and transmitted to the secondary pulley 10 via the belt 11 as the same rotation,
Further, the rotation is transmitted to the differential device 6 through the output gear 15 and the ring gear 65 as reverse rotation. Thus, the left and right drive shafts 16a and 16b drive the wheels in the reverse direction.

In the above embodiment, the forward / reverse switching device 3 is connected to the first pulley 9 on the upstream side of the transmission of the primary pulley 9.
Although arranged on the shaft I, the present invention is not limited to this, and may be arranged, for example, on the second shaft at a transmission intermediate portion between the secondary pulley and the output gear.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram showing a continuously variable transmission according to the present invention.

FIG. 2 is a sectional view of a continuously variable transmission according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 continuously variable transmission (CVT) 2 torque converter 3 forward / reverse switching device 5 belt-type continuously variable transmission 6 differential device 7 case 9 primary pulley 10 secondary pulley 11 belt 12 input side (input shaft) 15 output gear 16a, 16b left and right Drive shaft 17 Simple planetary gear 19 Fixed sheave 19a Flange 25 Carrier plate 25a Flange 25b Brake hub 25c Clutch hub 30 Sun gear disk 30a Flange 30b Stepped portion 31 Ring gear plate 31a Flange 31b Stepped portion 32 (ball) bearing 36 Cavity CR Carrier R Ring gear S Sun gear B Forward brake C Reverse clutch I First axis II Second axis III Third axis

Claims (6)

[Claims] 1. A continuously variable transmission in which a forward / reverse switching device, a belt-type continuously variable transmission, and a differential device are incorporated in a case, wherein the forward / reverse switching device has one simple planetary gear. A reverse brake that connects a sun gear of the planetary gear to an input side, connects a ring gear to an output side, and can further lock a carrier;
A reverse shaft capable of connecting two of the elements, a first shaft aligned with a primary pulley of the belt-type continuously variable transmission, a second shaft aligned with a secondary pulley, and the differential Third aligned with the left and right drive axes of the device
A continuously variable transmission comprising a shaft. 2. The forward / reverse switching device is disposed on the first shaft on the upstream side of transmission of the primary pulley, the ring gear is connected to a fixed sheave of the primary pulley, and the sun gear is connected to an input shaft. The continuously variable transmission according to claim 1, wherein the reverse clutch is interposed between the input shaft and the carrier. 3. An annular flange is provided on the back surface of the primary pulley, a bearing is fitted on the outer periphery of the flange and supported by the case, and a cavity is provided on the inner diameter side of the flange. The ring gear plate fixed to the ring gear is connected to an inner peripheral surface of the flange portion in the cavity, and a sun gear disk on which the sun gear is formed is connected to the input shaft. Step transmission. 4. The ring gear plate has a flange portion extending in the axial direction on the primary pulley side on the inner diameter side and a stepped portion on an intermediate portion, and the front sun gear disk has the primary sun gear disk on the inner diameter side. It has a flange portion extending in the axial direction on the pulley side and has a stepped portion in the middle portion, and both flange portions of the ring gear plate and the sun gear disk partially overlap in the axial direction so that the flange portion of the fixed sheave or The continuously variable transmission according to claim 3, wherein the continuously variable transmission is coupled to an input shaft, and the stepped portions are arranged so as to partially overlap in the axial direction. 5. The carrier has a brake hub extending axially on the outer diameter side opposite to the primary pulley, a flange portion extending axially on the inner diameter side toward the primary pulley, and an intermediate part thereof. And a carrier plate having a clutch hub extending on the opposite side to the primary pulley at a portion. The carrier plate is rotatably supported on the input shaft by the flange portion, and the flange portion is connected to the sun gear disk. The continuously variable transmission according to claim 4, wherein the continuously variable transmission is housed inside the stepped portion. 6. The continuously variable transmission according to claim 1, wherein a gear ratio between the ring gear and the sun gear is in a range of 1.4 to 1.5.