JP3074323B2 - Two-way differential clutch for continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-way differential clutch in a continuously variable transmission.

[0002]

2. Description of the Related Art The schematic structure of a conventional continuously variable transmission will be described with reference to FIG. 1. The rotation of a drive shaft DS on the engine ENG side is transmitted to an input shaft IS, and the rotation of the input shaft IS is applied to the input shaft IS. A belt V mounted between a pair of detachable input pulleys IP1 and IP2 attached to the shaft IS and a pair of detachable output pulleys OP1 and OP2 attached to the output shaft OS. , And transmitted to the output shaft OS in a stepless manner, and further transmitted to the drive wheels W. In addition, as a power transmission path, in addition to the main power transmission path via the belt V, an auxiliary power transmission path for transmitting power to the output shaft OS via a two-way differential clutch CL is provided. FIG. 2 is a longitudinal sectional view of the two-way differential clutch CL,
FIG. 3 is a cross-sectional view taken along the line AA of FIG. 2, FIGS. 4 and 5 are operation explanatory views, and FIG. 6 is an enlarged view of a main part. In FIG. 2, reference numeral 1 denotes a rotating shaft, which has various steps on its outer peripheral surface. Reference numeral 4 denotes an output gear, which is connected to one step of the rotating shaft 1 by a spline 4b. 4a are teeth provided on the outer periphery of the output gear 4 and mesh with a gear (not shown) on the output shaft OS side. 1
Reference numeral 7 denotes an outer cylindrical surface, which is formed in another step on the outer periphery of the rotating shaft 1 in parallel with the input gear 2. The input gear 2 has an inner peripheral cylindrical surface 18 and is externally inserted with a gap around the outer peripheral cylindrical surface 17. 2b is the input gear 2
Are meshed with gears (not shown) on the drive shaft DS side.

As can be seen from the enlarged view of the main part of FIG. 6, a plurality of sprags 6 are arranged at predetermined intervals in the circumferential direction between the inner cylindrical surface 18 of the input gear 2 and the outer cylindrical surface 17 of the rotary shaft 1. It is arranged. The cylindrical surface 1 facing the sprag 6
In the neutral state in which the cylindrical surface 1 and the cylindrical surface 1 are located between the sprags 6 and 7 in the neutral state.
A radial gap is formed between 7 and 18. Also, when the sprag 6 falls down in the circumferential direction of the cylindrical surfaces 17 and 18 from the neutral state, the inner-diameter arc surface 6a and the outer-diameter arc surface 6b engage with the opposing cylindrical surfaces 17 and 18. The outer diameter end of the sprag 6 fits into a pocket 9a of an outer holding member 9 fixed to the inner peripheral cylindrical surface 18 of the input gear 2 by press fitting or the like. And between the rotary shaft 1 and the pocket 10 a of the inner holding member 10 slidably inserted into the input gear 2. The dimension between the peripheral sides of the pocket 9a in the outer holding member 9 in the circumferential direction is smaller than the dimension between the peripheral sides of the pocket 10a in the inner holding member 10 in the circumferential direction.
A concave portion 10b is formed at the center of the side surface of the inner holding member 10 which faces the pocket 10a in the circumferential direction. When pressed, the sprag 6 is held in a neutral state as shown in FIG. Here, a leaf spring, a Koly spring, or the like can be used as the elastic body 7. In addition, H in the figure is a hole for discharging iron powder or the like.

Returning to FIG. 2, reference numeral 8 denotes a sub gear, which is provided in parallel with the input gear 2. Reference numeral 8a denotes teeth provided on the outer periphery of the sub gear 8, and the drive shaft D
The gear meshes with the S-side gear. The inner holding member 10 is slidably inserted into the inner periphery of the input gear 2 on the inner periphery side of the sub gear 8. The sub gear 8 is pressed by a disc spring 19 between a retaining ring 20 attached to the inner holding member 10 and a side surface of the step portion of the inner holding member 10. A notch 11 is provided by partially cutting the inner peripheral side of the outer holding member 9, while a stopper 1 a is protrudingly provided on the inner holding member 10 at a position facing the notch 11. Reference numerals 12 and 14 denote bearings for supporting the rotating shaft 1, and 13 denotes the input gear 2 and 1
5 is a bearing for supporting the inner holding member 10.

The operation of the two-way differential clutch constructed as described above will be described. The rotation of the gear on the drive shaft DS side is transmitted to the input gear 2 and the sub gear 8 meshing therewith. However, the teeth 2b of the input gear 2
For example, while the number of teeth is 53, the teeth 8a of the sub gear 8
Is set to, for example, 54 teeth, and has the same drive shaft D
Due to the rotation of S, the rotation of the sub gear 8 is delayed from the rotation of the input gear 2. Therefore, as shown in FIG. 5, the inner holding member 10 pressed against the sub gear 8
Rotates relative to the rotation of the input gear 2 until the stopper 1 a comes into contact with the end face of the notch 11 of the outer holding member 9 with a speed difference from the rotation of the input gear 2. The sprags 6 accommodated in the pockets 10a of the inner holding member 10 are
It falls in the rotation direction of 0. Therefore, as shown in FIG.
The inner diameter side arc surface 6a and the outer diameter side arc surface 6b of the sprag 6 are engaged with the opposed cylindrical surfaces 17 and 18, so that the clutch can be operated, that is, the sprag can be clamped.

Here, when the vehicle is running at a high speed,
Since the output gear 4, that is, the rotation of the rotary shaft 1 is set to rotate faster than the rotation of the input gear 2, the sprag 6 receives a frictional force in a rising direction and idles,
It does not bite into the cylindrical surfaces 17 and 18. In contrast,
When the vehicle is in the starting state, the rotation of the input gear 2 is set to be faster than the rotation of the output gear 4, that is, the rotation of the rotating shaft 1, and the clutch operates to reduce the rotating force of the input gear 2 to the rotating shaft 1. To be communicated to.
After the stopper 1a comes into contact with the wall surface of the notch 11, the inner holding member 10 idles with respect to the sub gear 8, so that the sub gear 8 is not damaged. As described above, the clutch operation principle of the sprag 6 due to the differential speed of the sub gear 8 does not depend on the direction of rotation of the input gear 2, so that the two-way differential clutch functions effectively even when the vehicle moves backward. It is configured.

The structure of the output pulleys OP1 and OP2 moves along the output shaft OS in opposition to a fixed output pulley OP1 provided integrally with the output shaft OS as shown in a sectional view of FIG. A movable output pulley OP2 is provided as much as possible, and a movable output pulley OP2 is provided.
Is provided with a belt tension mechanism for applying tension to the belt V. In this belt tension mechanism,
In order to apply a tension to the belt V, a torque cam 20 is fixed or formed integrally with the pulley OP2 on the back outer surface side of the movable output pulley OP2.
0 on the cam surface 20a having the wedge angle α at the right end, the output shaft O
Corresponding cam surfaces 21a of the hub 21 fixed to the S are abutted, and a perspective view of the torque cam 20 and the hub 21 is shown in FIG.

A compression coil spring 22 is mounted between the hub 21 and the outer surface of the movable output pulley OP2. The compression coil spring 22 is rotated by the torque T applied via the belt V to rotate the output shaft OS. Is rotated, the cam surface 21a of the hub 21 slides on the cam surface 20a of the torque cam 20, and an axial thrust F is generated by the wedge angle α, and the torque cam 20 and the movable output pulley OP2 are fixed to the output pulley. The belt V is pressed toward the OP1 side, whereby tension is applied to the belt V. The cam surface 20a of the torque cam 20 has a forward cam surface portion 20a1 and a retreat cam surface portion 20a2, and the corresponding cam surface 21a of the hub 21 similarly has a forward cam surface portion 21a.
1 and the cam surface portion 21a2 on the retreat side, so that a thrust can be obtained regardless of the traveling direction (rotation direction).

[0009]

However, in such a cam surface structure of the torque cam 20 and the hub 21, due to the structure, a play in which the cam surface 20a and the cam surface 21a do not contact each other occurs around the output shaft OS shown in FIG. It exists within the range of the rotation angle θc. On the other hand, also in the two-way differential clutch CL,
At the time of switching between forward and backward, the clamped state of the sprag 6 can be obtained only after the drive shaft DS rotates a predetermined angle θ. Therefore, in the relationship between the rotation angle θc and the angle θ,
There is a case where switching between forward and backward movement of the two-way differential clutch CL cannot be performed effectively.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and its gist is to provide a pair of detachable input side pulleys attached to an input shaft and an output shaft. A continuously variable transmission that continuously changes the rotation of an input shaft and transmits the rotation to an output shaft by a belt mounted between a pair of detachable output side pulleys attached to the output pulley,
A main power transmission path for transmitting rotation of the engine via the belt; and a sub power transmission path for transmitting the rotation of the engine to the output shaft via a two-way differential clutch.
A rotating shaft for transmitting rotation to the output shaft, an input gear rotatable relative to the rotating shaft, and rotationally driven by a drive shaft on the engine side, and the input shaft similarly rotated and driven by the drive shaft; A sub-gear having a greater number of teeth than a gear, and being interposed between the input gear and the rotary shaft, clamping the input gear and the rotary shaft based on a differential speed between the input gear and the sub-gear; And a cam surface is formed on the outer surface of the movable pulley in the output side pulley over the entire circumference concentrically with the output shaft as a belt tension mechanism for applying tension to the belt. A continuously variable transmission comprising a torque cam, and a hub attached to the output shaft and having a cam surface that abuts the cam surface of the torque cam. The sub of the two directions differential clutch
The number of gear teeth is determined by the following equation: θ <θc · ig · ip (where,
θ: the drive required until the sprags are clamped
The rotation angle of the shaft, θc: the torque cam and the hub
Play angle between cam surfaces, ig: between the input shaft and the drive shaft
Gear ratio, ip: pulley ratio between the input shaft and output shaft)
Holds, and the equation of θ = θs / (Z / Zi−Z / Zs) (this
Here, θs: switch angle (rotation required to switch back and forth
Angle), Z: Number of drive gear teeth of the drive shaft on the engine side, Zi:
Input gear teeth number, Zs: number of sub gear teeth)
That is, the number of teeth is set .

[0011]

[Function] The sub gear is a gear unrelated to power transmission,
By setting the number of teeth of this sub gear to be large, the rotation angle of the drive shaft required until the sprags are clamped can be set smaller than the play angle between the cam surface of the torque cam and the hub. Can be effectively switched back and forth.

[0012]

An embodiment of the present invention will be described below with reference to FIGS. As described in the above-mentioned conventional example, in the cam surface structure of the torque cam 20 and the hub 21 in the belt tension mechanism, the cam surface 20a and the cam surface 21a
Is present in the range of the rotation angle θc about the output shaft OS. On the other hand, also in the two-way differential clutch CL, when switching between forward and backward movement, the drive shaft DS is set at the predetermined angle θ.
Only after the rotation, the sprag 6 can be clamped. Here, assuming that the gear ratio between the input shaft IS and the drive shaft DS is ig and the pulley ratio between the input shaft IS and the output shaft OS is ip, when the drive shaft DS rotates by θ (rad), the output shaft OS becomes θ / rad. ig / ip rotation.
Therefore, the condition in which the forward / reverse switching can be performed in the two-way differential clutch CL is expressed by the following formula: θ / ig / ip <θc (rad). That is, it is represented by θ <θc · ig · ip.

On the other hand, in the two-way differential clutch CL,
The rotation angle θ of the drive shaft DS required from the start of rotation to the clamping of the sprag 6, that is, the rotation angle required for switching between forward and backward movement, is determined by the number of teeth of the input gear 2 and the sub gear 8 and the switch angle (the inside required for switching between forward and backward movement). Rotation angle of the holding member 10 with respect to the input gear 2),
= Θs / (Z / Zi−Z / Zs). Here, θs: switch angle (rad), Z: number of drive gear teeth, Zi: number of input gear teeth, and Zs: number of sub gear teeth.

Here, the number of teeth Zs of the sub gear 8 is a parameter that can be freely set without affecting the total reduction ratio of the continuously variable transmission.
Is set to a large value and θ is reduced, so that the forward / reverse switching of the two-way differential clutch CL can be effectively performed.

[0015]

According to the present invention, by setting the number of teeth of the sub gear irrespective of the total reduction ratio to be large, the two-way differential clutch using the sprags can be effectively switched between forward and backward. There is an advantage that the forward / reverse switching of the two-way differential clutch can be reliably performed without affecting the total reduction ratio.

[Brief description of the drawings]

FIG. 1 is a schematic view of a continuously variable transmission.

FIG. 2 is a longitudinal sectional view of a two-way differential clutch.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a diagram illustrating the operation of a two-way differential clutch.

FIG. 5 is an explanatory diagram of an operation of the two-way differential clutch.

FIG. 6 is an enlarged view of a main part of FIG. 3;

FIG. 7 is a sectional configuration diagram of a belt tension mechanism.

FIG. 8 is a perspective view of a torque cam and a hub constituting a belt tension mechanism.

[Explanation of symbols]

 Reference Signs List 1 rotation shaft 2 input gear 4 output gear 6 sprag 8 sub gear 20 torque cam 21 hub 20a, 21a cam surface DS drive shaft IS input shaft OS output shaft IP1, IP2 input pulley OP1, OP2 output pulley V belt CL two-way difference Dynamic clutch

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16H 9/12 F16D 41/10

Claims (1)

(57) [Claims] 1. A belt mounted between a pair of detachable input side pulleys attached to an input shaft and a pair of detachable output side pulleys attached to an output shaft. Continuously variable transmission for continuously transmitting the rotation of the engine to an output shaft by transmitting the rotation of the engine to the output shaft via a main power transmission path via the belt and a two-way differential clutch. An auxiliary power transmission path, wherein the two-way differential clutch is rotatable relative to the rotation shaft for transmitting rotation to the output shaft, and
An input gear that is rotationally driven by an engine-side drive shaft, a sub-gear that is similarly rotationally driven by the drive shaft and has more teeth than the input gear, and is interposed between the input gear and the rotary shaft. A sprag for clamping the input gear and the rotating shaft based on a speed difference between the input gear and the sub gear, and a belt tension mechanism for applying tension to the belt, wherein the output is A torque cam having a cam surface formed on the outer surface of the movable pulley in the side pulley over the entire circumference concentric with the output shaft, and attached to the output shaft;
And a hub having a cam surface that comes into contact with the cam surface of the torque cam. In the continuously variable transmission, the number of teeth of the sub-gear of the two-way differential clutch is expressed by the following equation : θ <θc · ig · ip , Θ: the sprag
Is the rotation angle of the drive shaft required for clamping, θ
c: play between the cam surface of the torque cam and the hub
Angle, ig: gear ratio between the input shaft and the drive shaft, ip:
The pulley ratio between the input shaft and the output shaft is established, and the equation θ = θs / (Z / Zi−Z / Zs) (where θ
s: switch angle (rotation angle required to switch between forward and backward)
Z: number of drive gear teeth of the drive shaft on the engine side, Zi: imp
Ttogiya number of teeth, Zs: number of teeth, which is determined by the sub gear number of teeth)
A two-way differential clutch in a continuously variable transmission, wherein the clutch is set to: