JPH04327055A - Continuously variable transmission - Google Patents

Abstract

PURPOSE:To realize the gear ratio from reverse rotation to positive rotation and allow the forward/reverse switching only by the control of the gear ratio of a frictional wheel type continuously variable transmission mechanism by combining an epicyclic transmission mechanism with the frictional wheel type continuously variable transmission mechanism. CONSTITUTION:An epicyclic transmission mechanism 24 consisting of a first epicyclic gear 50 and a second epicyclic gear 60 is provided between a first continuously variable transmission mechanism 12 and a second continuously variable transmission mechanism 14. The first internal gear 52 of the first epicyclic gear 50 is fixed to a static part, a first piston carrier 59 is connected to the output disks 18, 28 of the first and second continuously variable transmission mechanisms, and a first sun gear 54 is connected to the second internal gear 62 of the second epicyclic gear 60. A second piston carrier 68 is connected to an input shaft 1, and a second sun gear 64 is connected to an output shaft 42.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuously variable transmission.

0002

2. Description of the Related Art A conventional friction wheel type continuously variable transmission is disclosed in Japanese Unexamined Patent Publication No. 2-163562. The friction wheel type continuously variable transmission shown in this figure includes a first input disk and a first output disk that are rotatably and axially movable, and a toroidal groove formed by both disks. a first continuously variable transmission mechanism including a pair of first friction rollers arranged in frictional contact;
a second input disk and a second output disk rotatably and axially movable; a pair of second input disks disposed in frictional contact with the disks within a toroidal groove formed by the disks; a second continuously variable transmission mechanism including a friction roller; a torque converter that transmits the rotation of the engine to the first input disk and the second input disk;
a countershaft that transmits the rotational force taken out between the first output disk and the second output disk to the output shaft;
A forward/reverse movement detection means provided at the tip of the counter shaft, an actuator capable of driving the friction roller to a predetermined inclination position, a speed change control device that outputs a drive signal to the actuator while feeding back the amount of inclination of the friction roller, and a stepless speed change control device. It has forward/reverse switching means provided on the rotational force input path to the transmission mechanism. The speed change control device is composed of a first speed change control device for forward movement only and a second speed change control device for reverse movement only. Switching between the first speed change control device and the second speed change control device is performed by a control device switching device based on a result of a forward/reverse motion detection device that determines whether the vehicle is in a forward or reverse state. When moving forward, the actuator is drive-controlled by the first speed change control device, while when the vehicle is moving backward, the actuator is drive-controlled by the second control device.

0003

[Problems to be Solved by the Invention] However, the conventional friction wheel type continuously variable transmission described above has a gear ratio in the range of 0.4 to 0.4.
In addition, a torque converter and a forward/reverse switching device are required for starting and switching between forward and backward travel, resulting in a large size.
Because it has a structure that allows it to be taken out from between the continuously variable transmission mechanism,
A countershaft is also required, which poses a problem in that the radial dimension of the entire transmission increases. The present invention aims to solve these problems.

0004

[Means for Solving the Problems] The present invention solves the above problems by providing a friction wheel type continuously variable transmission mechanism with a planetary gear transmission mechanism consisting of two planetary gears. That is, the continuously variable transmission according to the present invention includes a friction wheel type continuously variable transmission mechanism and a planetary gear transmission mechanism (24), and the friction wheel type continuously variable transmission mechanism includes an input disk (16, 26), an output disk (18, 28), and friction rollers (20, 30) that are provided in a toroidal groove formed by both disks to make the contact state with both disks variable, and the input disk has an input shaft (10, ), and the planetary gear transmission mechanism is connected to the first internal gear (5
2), a first planetary gear (54) having a first sun gear (54), and a double pinion type first pinion carrier (59);
50), and a second planetary gear (60) having a second internal gear (62), a second sun gear (64), and a single pinion type or double pinion type second pinion carrier (68). The first internal gear is fixed to the stationary part (40), the first pinion carrier is connected to the output disk, the first sun gear is connected to the second internal gear, and the second pinion carrier is connected to the second internal gear. is connected to the input shaft, and the second sun gear is connected to the output shaft (42). Note that the numbers in parentheses above are the codes of corresponding members in the embodiments described later.

[0005]

[Operation] The rotation input to the first pinion carrier is controlled by the friction wheel type continuously variable transmission mechanism, for example, - relative to the input rotation 1.
It changes in the range of 0.5 to -2.0. In response to changes in the rotation of the first pinion carrier, the output shaft connected to the second sun gear is rotated from reverse to stop to forward rotation. Therefore, by simply controlling the gear ratio of the friction wheel type continuously variable transmission mechanism, reversing, stopping at idling,
It is possible to start and run in overdrive. As a result, a torque converter, forward/reverse switching mechanism, etc. are not required. Further, the input shaft and the output shaft can be arranged concentrically.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a basic configuration diagram of a friction wheel type continuously variable transmission according to the present invention. Input shaft 10 to which engine torque is transmitted
A first continuously variable transmission mechanism 12 and a second continuously variable transmission mechanism 1 are concentrically connected to the
4 is provided. The first continuously variable transmission mechanism 12 includes a first input disk 16, a first output disk 18, and a pair of first input disks 16 and a first output disk 18, which are arranged in a toroidal groove formed by both disks so as to be in frictional contact with both disks. 1 friction roller 20
It has . The first input disk 16 rotates together with the input shaft 10 via a ball spline 22 and is movable in the axial direction. The first output disk 18 is the input shaft 1
It is connected to a planetary gear transmission mechanism 24 concentric with 0 as will be described later. The second continuously variable transmission mechanism 14 also includes the first continuously variable transmission mechanism 12
Similarly, the second input disk 26 and the second output disk 2
8, and a pair of second friction rollers 30 disposed in a toroidal groove formed by both disks so as to be in frictional contact with both disks. The second input disk 26 rotates together with the rotating shaft 11 via a ball spline 32 and is movable in the axial direction. In addition, the rotation axis 1
1 is connected to the input shaft 10 so as to rotate together with the input shaft 10. The second output disk 28 is coupled to the planetary gear transmission mechanism 24 as described below. Note that the arrangement of the second input disk 26 and the second output disk 28 is opposite to that of the first continuously variable transmission mechanism 12. That is, the first continuously variable transmission mechanism 12 and the second continuously variable transmission mechanism 14 are arranged such that the first output disk 18 and the second output disk 28 are adjacent to each other. A loading cam device 34 is provided outside the first input disk 16, to which engine rotation is input, and a pressing force corresponding to this input torque is generated by the loading cam device 34 and the disc spring 38. The cam plate 34a of the loading cam device 34 is relatively rotatably fitted to the input shaft 10 and is attached to the input shaft 10 via a thrust bearing 36. Also, the second
The right end wall 40 of the input disk 26 and casing 40 in the figure
A disc spring 38 is provided between the disc spring 38 and the disc spring 38. The pressing force generated by the loading cam device 34 and the disc spring 38 is applied to the first input disk 16 via the input shaft 10 and the rotating shaft 11.
and acts on the second input disk 26.

The planetary gear transmission mechanism 24 is disposed between the first continuously variable transmission mechanism 12 and the second continuously variable transmission mechanism 14, and includes a first planetary gear 50 of a double pinion type and a second planetary gear of a single pinion type. 60. In addition, a single pinion type planetary gear has a single pinion gear that meshes with both the internal gear and the sun gear, while a double pinion type planetary gear has two pinion gears that mesh with each other, one of which meshes with the internal gear and the other. is the one that meshes with Sangiya. First planetary gear 50
A first internal gear 52, a first sun gear 54, and two first pinion gears 56 and 58 that mesh with each other.
The first pinion carrier 59 supports the first pinion carrier 59. The first internal gear 52 meshes with one first pinion gear 56, and the first sun gear 54 meshes with the other first pinion gear 58. The second planetary gear 60 includes a second internal gear 62, a second sun gear 64, and a second pinion carrier 68 that supports a second pinion gear 66 that meshes with the second internal gear 62 and the second sun gear 64 at the same time. ing. The first internal gear 52 is always fixed to the casing 40, and the first pinion carrier 59 is connected to the first output disk 18 and the second output disk 2.
It is connected to 8. The first sun gear 54 is connected to a second internal gear 62 of a second planetary gear 60 . The second pinion carrier 68 includes the input shaft 10 and the rotation shaft 11
is connected to. The second sun gear 64 is connected to the output shaft 42 .

FIG. 2 is a diagram showing the relationship between the rotational speeds of each element of the planetary gear. Generally, in a single pinion type planetary gear, if the rotation speeds of the internal gear, pinion carrier, and sun gear are NR, NPC, and NS, respectively, and (number of teeth of sun gear)/(number of teeth of internal gear) is b, then these Between is NR+b×NS-(1+b)×N
The relational expression PC=0 holds true. Therefore, the vertical axes indicating the rotational speed of the second internal gear 62, second sun gear 64, and second pinion carrier 68 are R2 axis and S2 axis, respectively.
2 axes and PC 2 axes, the PC 2 axis is placed between the R2 axis and the S2 axis, and the distance between the R2 axis and the PC 2 axis and the PC
If the ratio of the distance between the two axes and the S2 axis is set to b, the coordinate axes of the intersections of any straight line on this coordinate with the R2 axis, the PC2 axis, and the S2 axis are shown in the above formula. You will be satisfied with your relationship. On the other hand, in a double pinion type planetary gear, if (number of teeth of sun gear)/(number of teeth of internal gear) is a, then NR-a×NS-(1-a)×NP
The relational expression C=0 holds true. Therefore, the vertical axes indicating the rotational speed of the first internal gear 52, the first sun gear 54, and the first pinion carrier 59 are the R1 axis and the S1 axis, respectively.
The R1 axis is placed between the S1 axis and the PC1 axis, and the ratio of the distance between the R1 axis and the PC1 axis and the distance between the PC1 axis and the S1 axis is a. If you do this,
The relationship in the above equation will be satisfied. Note that since the first sun gear 54 and the second internal gear 62 are connected to each other, the S1 axis and the R2 axis are drawn coaxially. The first internal gear 52 is always fixed to a stationary part, so it takes a point on the R1 axis where the rotation speed is 0, and the second pinion carrier 68 is connected to the input shaft 10, so it takes a point on the PC2 axis where the rotation speed is 1. take. Since the first pinion carrier 59 is connected to the first output disk 18 and the second output disk 28, the output rotation speed thereof is taken on the PC1 axis. Since the second sun gear 64 is connected to the output shaft 42, a point on the S2 axis indicates the output rotation of the output shaft 42. FIG. 2 shows a case where the output rotational speed of the first output disk 18 and the second output disk 28 changes between -0.5 and -2. First, take a point of -0.5 on the PC1 axis and 0 on the R1 axis.
Connect with the points. The intersection of this line and the S1 axis is connected to the point at which the rotation speed of the PC2 axis is 1, and the intersection of this line and the S2 axis is determined. This intersection point is when the rotational speed of the output disks 18 and 28 is -0.
5 shows the rotation speed of the output shaft 42 when the rotation speed is 5. Next, take the -2 point on the PC1 axis and connect the line in the same way as above. From this result, when the rotation speed of the output disks 18 and 28 is -0.5, the rotation speed of the output shaft 42 is about 1.8, so the output shaft 42 is in a state where the speed is increased compared to the input shaft 10. It will rotate. Also, when the rotation speed of the output disks 18 and 28 is -2, the rotation speed of the output shaft 42 is -0.5, and the rotation of the output shaft 42 is opposite to the rotation of the input shaft 10, so the car cannot move backward. become. In addition, output disks 18 and 2
When the number of rotations of the output shaft 42 is approximately 1.6, the number of rotations of the output shaft 42 becomes zero. Therefore, when the output rotation speed of the continuously variable transmission mechanism is changed between -0.5 and -2, the output shaft 42 is
It will rotate between -0.5 and -0.5. Expressing this rotational relationship mathematically, NS2=((1-a)/(a・b)
)×NPC1+(1/b)+1. By changing the values of a and b, the above-mentioned rotation speed can be adjusted to some extent.

Although the second planetary gear 60 is of a single pinion type in the above embodiment, it is not necessarily limited to this, and the second planetary gear 60 may be of a double pinion type. FIG. 3 is a diagram showing the relationship between the rotational speeds of each element when the second planetary gear 60 is a double pinion. When the output rotation speed of the continuously variable transmission mechanism is changed between -0.5 and -2 as in the above embodiment, the rotation speed of the output shaft 42 becomes almost the same as that of the single pinion type.

0010

As explained above, according to the present invention, a friction wheel type continuously variable transmission mechanism is provided with a planetary gear transmission mechanism consisting of a first planetary gear and a second planetary gear. By controlling the gear ratio of the continuously variable transmission, the output shaft can rotate from reverse to forward rotation. That is, it is possible to achieve a gear ratio from infinity to overdrive, and even reverse. Therefore, there is no need for a torque converter or forward/reverse switching device, and since the input and output shafts can be arranged concentrically, the radial dimension of the transmission can be reduced, resulting in a significantly smaller transmission. can be converted into

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of an embodiment of a friction wheel type continuously variable transmission of the present invention.

FIG. 2 is a diagram showing the relationship between the rotational speeds of each element of the planetary gear shown in FIG. 1;

FIG. 3 is a diagram showing the relationship between the rotational speeds of each element of a planetary gear according to another embodiment.

[Explanation of symbols]

10 Input shaft 11 Rotation axis 12 First continuously variable transmission mechanism 14 Second continuously variable transmission mechanism 16 First input disk 18 First output disk 20 First friction roller 24 Planetary gear transmission mechanism 26 Second input disk 28 Second output disk 30 Second friction roller 42 Output shaft 50 1st planetary gear 52 1st internal gear 54 1st Sangiya 59 1st pinion carrier 60 Second planetary gear 62 2nd internal gear 64 Second Sangir 68 2nd pinion carrier

Claims (1)

[Claims] Claim 1: Consisting of a friction wheel type continuously variable transmission mechanism and a planetary gear transmission mechanism, the friction wheel type continuously variable transmission mechanism consists of an input disk, an output disk, and a toroidal groove formed by both disks. The input disk is connected to the input shaft so as to rotate integrally with the input shaft, and the planetary gear transmission mechanism includes a first internal gear, a first sun gear, a first sun gear, and a first internal gear. and a first planetary gear having a double pinion type first pinion carrier, a second internal gear, a second sun gear,
and a second planetary gear having a single pinion type or double pinion type second pinion carrier, the first internal gear is fixed to a stationary part, and the first pinion carrier is connected to the output disk. The continuously variable transmission is characterized in that the first sun gear is connected to the second internal gear, the second pinion carrier is connected to the input shaft, and the second sun gear is connected to the output shaft. Machine.