JP2003028250A - Pulley width adjuster for continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure with an excellent transmission efficiency and a low cost as an actuator 19 for adjusting a clearance between a fixed pulley element 2 and a displaceable pulley element 3. SOLUTION: The ball screw type actuator 19 comprises a fixed male ball screw cylinder 21 provided with a male ball screw groove 32 in an outer circumference, a female ball screw cylinder 33 provided with a female ball screw groove 40 in an inner circumference and rotatively driven by an electric motor, a plurality of balls 41, 41 and a first ball bearing 35 disposed between the displaceable pulley element 3 and a tip portion of the female ball screw cylinder 33. An outer ring raceway 36 forming the first ball bearing 35 and an outer ring raceway 24 forming a second ball bearing 23 disposed between a base end portion of the male ball screw cylinder 21 and an end of a rotary shaft 1 are formed direct in part of inner circumferences of the female ball screw cylinder 33 and the male ball screw cylinder 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION A pulley width adjusting device for a continuously variable transmission according to the present invention is incorporated in a continuously variable transmission for various mechanical devices such as automobiles and industrial machines, and is provided between a drive shaft and a driven shaft. It is for adjusting the width of the drive pulley or the driven pulley in order to change the gear ratio.

[0002]

2. Description of the Related Art Continuously variable transmissions have become widely used in recent years as automatic transmissions for automobiles because the output of the engine can be utilized in the best condition. Among these, as a belt type continuously variable transmission, the one described in Japanese Patent No. 2744038 is conventionally known. The belt type continuously variable transmission is, for example, as described in this publication, a pulley (primary pulley) provided on the drive shaft side and a pulley (secondary pulley) provided on the driven shaft side, each of which has an adjustable width. (Pulley) and endless belt.
When changing the gear ratio between the drive shaft and the driven shaft, the widths of the primary pulley and the secondary pulley are changed in opposite directions in synchronization with each other. For example, when changing to the speed increasing side, the width of the primary pulley is narrowed and the width of the secondary pulley is widened to move the endless belt to the outer diameter side of the primary pulley and to the inner diameter side of the secondary pulley. Let On the contrary, when changing to the deceleration side, the width of the primary pulley is widened and the width of the secondary pulley is narrowed to move the endless belt to the inner diameter side of the primary pulley and to the outer diameter side of the secondary pulley. Let

As a pulley width adjusting device for a continuously variable transmission for adjusting the width of a pulley of the above-mentioned endless belt type continuously variable transmission, a structure having a structure as shown in FIG. 5 is conventionally known. There is. In this pulley width adjusting device for a continuously variable transmission, a fixed pulley piece 2 is fixed to one end (right end in FIG. 5) of a rotary shaft 1, and a displacement pulley piece 3 is fixed to an intermediate part of the rotary shaft 1. Only the axial displacement of the rotary shaft 1 is supported. A rotary cylinder 4 is rotatably supported on the displacement side pulley piece 3 by a deep groove type first ball bearing 5 capable of supporting a radial load and a thrust load. Then, one end of the rotary cylinder 4 (see FIG.
The female screw 6 formed on the inner peripheral surface of the left end) is screwed with the male screw 8 formed on the outer peripheral surface of the fixed cylinder 7 supported and fixed inside the transmission case 12. Further, the rotary shaft 1 is provided inside the transmission case 12 with the second and third ball bearings 1
It is rotatably supported by 3 and 14. Further, the driven gear 9 fixed to the outer peripheral surface of the rotary cylinder 4 and the drive shaft 1
Drive gear 11 provided on the rotary cylinder 4
Is freely rotatable. When changing the gear ratio,
The rotary cylinder 4 is rotated to displace the displacement-side pulley piece 3 in the axial direction together with the rotary cylinder 4, so that the inner surface of the displacement-side pulley piece 3 and the inner surface of the fixed-side pulley piece 2 are spaced apart from each other. A certain pulley width is changed in synchronization with the driving side and the driven side.

[0004]

In the case of the above-mentioned conventional structure, an actuator for displacing the displacement side pulley piece 3 in the axial direction of the rotary shaft 1, a rotary cylinder 4 having an internal thread 6 formed on its inner peripheral surface, It is composed of a fixed cylinder 7 having an external thread 8 formed on the outer peripheral surface thereof, and a first ball bearing 5 provided between the rotary cylinder 4 and the displacement side pulley piece 3. Then, the female screw 6 and the male screw 8 are screwed together. Since the contact state between the female screw 6 and the male screw 8 includes sliding contact, it is difficult to sufficiently reduce the friction loss in the engaging portion between the both screws 6, 8 and the transmission efficiency in the actuator portion is sufficient. It may not be possible to secure it. If the transmission efficiency cannot be sufficiently secured in this way, the electric power consumption of the electric motor used to operate the actuator becomes large. Further, in this case, the electric motor becomes large in size, which causes a large size of the entire pulley width adjusting device including the electric motor.

Further, in the case of the above-mentioned conventional structure, the first ball bearing 5 for supporting the rotary cylinder 4 around the displacement side pulley piece 3 is provided.
The outer ring 15 constituting the above is provided separately from the rotary cylinder 4 and is internally fitted and fixed to the inner peripheral surface of the distal end portion of the rotary cylinder 4. Further, of the second and third ball bearings 13 and 14 for supporting the rotary shaft 1 inside the transmission case 12, the second provided on the other end side (the left end side in FIG. 5) of the rotary shaft 1 Ball bearing 14
The outer ring 16 constituting the above is provided separately from the fixed cylinder 7, and is fitted and fixed to the inner peripheral surface of the base end portion of the fixed cylinder 7. Therefore, when the pulley width adjusting device is assembled, the outer rings 15 and 16 forming the first and second ball bearings 5 and 13 are partially inserted into the rotary cylinder 4 and the fixed cylinder 7. It requires a troublesome work of fitting and fixing. Also, each outer ring 1
It becomes necessary to strictly regulate the diameters of the outer peripheral surfaces of 5 and 16 and the partial inner peripheral surfaces of the rotary cylinder 4 and the fixed cylinder 7, respectively. Performing such a troublesome work of fitting the outer rings 15 and 16 inside and fixing the diameter of a predetermined portion strictly causes a cost increase of the pulley width adjusting device.
Further, in order to secure the strength of the outer rings 15 and 16, it is necessary to increase the radial thickness of the outer rings 15 and 16 to some extent. Therefore, each of these outer rings 15, 16
And a part of the rotary cylinder 4 or the fixed cylinder 7 for fitting and fixing
There is a limit to reducing the diametrical dimension of the portion including the first and second ball bearings 5 and 13, which makes it difficult to reduce the size and weight of the pulley width adjusting device.

Further, since the outer races 15 and 16 constituting the respective ball bearings 5 and 13 are provided separately from the rotating barrel 4 or the fixed barrel 7, the outer races are accompanied by the use of the pulley width adjusting device. There is a possibility that relative sliding may occur between the outer peripheral surfaces of 15 and 16 and the inner peripheral surfaces of the rotary cylinder 4 and the fixed cylinder 7. When such relative slippage occurs, damage such as wear may occur on the fitting surfaces of the outer rings 15 and 16 and the rotary cylinder 4 and the fixed cylinder 7, or heat generated due to the relative slippage may cause First, above
The second ball bearings 5 and 13 and a part of the actuator may be seized or deformed. In view of such circumstances, the present invention has been made to eliminate any inconvenience that occurs in the conventional structure.

[0007]

The pulley width adjusting device for a continuously variable transmission according to the present invention is one of the endless belts as in the previously known pulley width adjusting device for a continuously variable transmission. It is incorporated in a continuously variable transmission that changes the gear ratio between the drive shaft and the driven shaft by changing the width of the pulley around which it is used, and is used to change the width of the pulley. Then, this pulley is provided with a fixed pulley piece supported around the rotary shaft so as to freely rotate in synchronism with the rotary shaft in a state where displacement of the rotary shaft in the axial direction is prevented, The displacement side pulley piece is supported so as to be freely displaceable and rotatable in synchronization with the rotation shaft, and an actuator for displacing the displacement side pulley piece in the axial direction of the rotation shaft.

Particularly, in the continuously variable transmission pulley width adjusting device of the present invention, the actuator includes a male ball screw cylinder, a female ball screw cylinder, a plurality of balls, and a first rolling bearing. Prepare Of these, the male ball screw cylinder is
It is fixed inside the transmission case, and has a male ball screw groove on the outer peripheral surface. The female ball screw cylinder is arranged concentrically with the male ball screw cylinder around the male ball screw cylinder and has a female ball screw groove formed on the inner peripheral surface thereof. The plurality of balls are provided between the female ball screw groove and the male ball screw groove. The first rolling bearing is provided between the inner peripheral surface of the distal end portion of the female ball screw cylinder and the outer peripheral surface of the cylindrical portion formed at the inner diameter side end of the displacement side pulley piece. Supports load and thrust load.

Further, in the pulley width adjusting device for a continuously variable transmission according to the first aspect, the outer ring raceway which constitutes the first rolling bearing is directly attached to the inner peripheral surface of the distal end portion of the female ball screw cylinder. Is forming. Further, in the pulley width adjusting device for a continuously variable transmission according to claim 2, the rotary shaft is rotatably supported inside the transmission case on the inner peripheral surface of the base end portion of the male ball screw cylinder. The outer ring raceway forming the second rolling bearing is directly formed.

[0010]

When the pulley width adjusting device for a continuously variable transmission of the present invention configured as described above is used to change the pulley width, it is controlled by a drive source such as an electric motor or the like through a transmission mechanism such as a gear reducer or the like. Rotate the ball screw cylinder. Then, with the rolling of a plurality of balls provided between the female ball screw groove formed on the inner peripheral surface of the female ball screw cylinder and the male ball screw groove formed on the outer peripheral surface of the fixed male ball screw cylinder. Then, the female ball screw cylinder is displaced in the axial direction. The axial displacement of the female ball screw cylinder is transmitted to the displacement side pulley piece via the first rolling bearing, and the displacement side pulley piece is displaced in the axial direction, so that the pulley width changes. As described above, in the case of the present invention, since the ball screw mechanism is used as the actuator for displacing the displacement side pulley piece in the axial direction of the rotating shaft,
It is possible to reduce friction loss in the actuator portion, improve transmission efficiency, and save energy.

Further, in the case of the present invention, the outer ring raceway forming the first rolling bearing or the second rolling bearing is directly formed on a part of the female ball screw cylinder or the male ball screw cylinder. Therefore, it is not necessary to internally fit and fix a separate outer ring to a part of the female ball screw cylinder or the male ball screw cylinder.
For this reason, the assembly work can be facilitated, and the dimensions of the respective predetermined parts, which are necessary when the outer ring of the separate body is fitted and fixed to the female ball screw cylinder or the male ball screw cylinder, must be strictly regulated. Can be lost. Therefore, the cost of the entire pulley width adjusting device can be reduced in combination with the fact that the number of parts can be reduced by omitting the outer ring. In addition, it prevents damage such as wear due to relative slippage that may occur when the separate outer ring is fitted and fixed to a part of the female ball screw cylinder or the male ball screw cylinder to ensure durability. It is possible to secure sufficient sex. Also, the diametrical dimension of the part including the part of the female ball screw cylinder and the first rolling bearing, or the part including the part of the male ball screw cylinder and the second rolling bearing is reduced in the diameter direction. As a result, the overall size and weight of the pulley width adjusting device for a continuously variable transmission can be reduced.

[0012]

1 and 2 show a first example of an embodiment of the present invention corresponding to claims 1 and 2. A fixed pulley piece 2 is fixed to one end (right end in FIG. 1) of a rotary shaft 1 which is a drive shaft or a driven shaft constituting a belt type continuously variable transmission, and a displacement side is fixed to an intermediate portion of the rotary shaft 1. Pulley piece 3
Only the axial displacement of the rotary shaft 1 is supported. That is, the key 17 locked on the outer peripheral surface of the rotating shaft 1
And the key groove 1 formed on the inner peripheral surface of the displacement side pulley piece 3
8, the displacement side pulley piece 3 is supported on the rotary shaft 1 so that the rotary shaft 1 can be displaced in the axial direction and can rotate in synchronization with the rotary shaft 1. .

The displacement pulley piece 3 is displaced in the axial direction of the rotary shaft 1 by the actuator 19. The actuator 19 includes a male ball screw cylinder 21, a female ball screw cylinder 33, and a plurality of balls 4.
It is constituted by the first and the fourth ball bearings 35.
Of these, the male ball screw cylinder 21 is fixed inside the transmission case 12. A part of the inner surface of the transmission case 12 has a bottomed concave hole-shaped storage portion 2 having a cylindrical inner peripheral surface.
0 is set. The base end portion (the left end portion in FIGS. 1 and 2) of the male ball screw cylinder 21 is fixed in the storage portion 20 concentrically with the storage portion 20. That is, the base end portion of the male ball screw cylinder 21 is internally fitted and fixed to the small diameter portion 22 provided concentrically with the storage portion 20 in the back portion of the storage portion 20 by interference fitting.

Then, between the inner peripheral surface of the base end portion of the male ball screw cylinder 21 and the outer peripheral surface of the other end portion (left end portion in FIGS. 1 and 2) of the rotary shaft 1, A deep groove type second ball bearing 23, which is a rolling bearing, is provided. And
In the case of the present invention, the outer ring raceway 24 is formed directly on the inner peripheral surface of the base end portion of the male ball screw cylinder 21. An inner ring 25 is fitted on the outer peripheral surface of the other end of the rotary shaft 1. The inner ring 25 includes a step surface 26 provided on the outer peripheral surface of the rotating shaft 1 near the other end (a portion near the left end of FIGS. 1 and 2) and an annular member 27 externally fitted and fixed to the other end of the rotating shaft 1. It is fixed to the rotating shaft 1 by being sandwiched between and. A plurality of balls 29, 29 are rotatably provided between the outer ring raceway 24 and an inner ring raceway 28 formed on the outer peripheral surface of the inner ring 25. Then, the second ball bearing 2 is attached to the inner diameter side portion of the proximal end portion of the male ball screw cylinder 21 including the outer ring raceway 24.
It has a function as an outer ring that composes 3.

On the other hand, a deep groove type third ball bearing 30 is provided between the outer peripheral surface of one end of the rotary shaft 1 and the inner surface of the transmission case 12. The third ball bearing 30 and the second ball bearing 23 rotatably support the rotary shaft 1 inside the transmission case 12.

The male ball screw cylinder 21 has an outer diameter smaller than the inner diameter of the housing portion 20. Therefore, a cylindrical space 31 is formed between the outer peripheral surface of the male ball screw cylinder 21 and the inner peripheral surface of the housing portion 20. A male ball screw groove 32 is formed on the outer peripheral surface of the male ball screw cylinder 21 from the portion facing the cylindrical space 31 to the tip portion (right end portion in FIG. 1). 1 shows only a part of the male ball screw groove 32 for simplification, but in the actual case, the male ball screw groove 32 is formed on the outer peripheral surface of the male ball screw cylinder 21. Formed in a wider area.

The first half of the male ball screw cylinder 21 fixed in the transmission case 12 as described above (the right half of FIG. 1).
A base half portion (the left half portion in FIG. 1) of the female ball screw cylinder 33 is positioned around the circumference of. This female ball screw cylinder 33
Shifts in the axial direction in synchronization with the displacement side pulley piece 3 when changing the pulley width.

The tip of the female ball screw cylinder 33 is
Cylindrical portion 3 formed at the inner diameter side end of the displacement side pulley piece 3
4 is connected by the deep groove type first ball bearing 35 corresponding to the first rolling bearing described in the claims and capable of supporting radial load and thrust load. Further, in the case of the present invention, the outer ring raceway 36 is formed directly on the inner peripheral surface of the distal end portion of the female ball screw cylinder 33. Further, the inner ring 3 is provided on the outer peripheral surface of the base end portion (right end portion in FIG. 1) of the cylindrical portion 34.
7 is abutted against the stepped surface 38 formed on the outer peripheral surface of the intermediate portion of the displacement side pulley piece 3, and is externally fitted and fixed by adhesion or the like. And the female ball screw cylinder 33
A plurality of balls 29, 29 are rotatably provided between an outer ring raceway 36 formed directly on the inner peripheral surface of the distal end of the inner ring 37 and an inner ring raceway 39 formed on the outer peripheral surface of an inner ring 37 fixed to the cylindrical portion 34. ing. The inner diameter side portion of the female ball screw cylinder 33 including the outer ring raceway 36 has a function as an outer ring forming the first ball bearing 35.

A female ball screw groove 40 is formed in a portion of the inner peripheral surface of such a female ball screw cylinder 33 near the intermediate base end. Then, the plurality of balls 41, 41 are provided between the female ball screw groove 40 and the male ball screw groove 32, and the female ball screw cylinder 33 is connected to the male ball screw cylinder 2.
Concentric support around 1. Further, the female ball screw groove 4 is formed at a portion of the female ball screw cylinder 33 near the intermediate base end.
The holding hole 42 is formed in a part of the portion where 0 is formed, and the circulation member 43 is installed in the holding hole 42. The circulation member 43 is for returning the ball 41 reaching one end of the female ball screw groove 40 to the other end, and has a conventionally known structure for a ball screw mechanism. In the illustrated example, a cylindrical sleeve 44 is externally fitted and fixed to the base half of the female ball screw cylinder 33 so that the circulation member 43 does not come out from the holding hole 42 in the radial direction. ing.

The female ball screw cylinder 33 is rotatably driven by an electric motor (not shown). For this reason, the drive gear 11 is externally fitted and fixed or integrally formed on the intermediate portion of the drive shaft 10 which is rotationally driven by an electric motor whose rotational direction is freely convertible. On the other hand, the driven gear 9 is externally fitted and fixed to the tip of the female ball screw cylinder 33. The driven gear 9 and the drive gear 11 are meshed with each other. Of these, the drive gear 11 is sufficiently secured in the axial direction, and the driven gear 9 and the drive gear 11 are irrespective of the axial displacement of the female ball screw cylinder 33 caused by changing the pulley width. Are kept in mesh with each other.

When changing the pulley width by the pulley width adjusting device for a continuously variable transmission according to the present invention having the above-mentioned structure, the electric motor is energized, and the electric power is supplied to the electric gear and the driven gear 9 and the driven gear 9. The female ball screw cylinder 33 is rotated in a predetermined direction. Then, the female ball screw groove 40 formed on the inner peripheral surface of the female ball screw cylinder 33 and the male ball screw groove 3 formed on the outer peripheral surface of the fixed male ball screw cylinder 21.
The female ball screw cylinder 33 is displaced in the axial direction with the rolling of the balls 41 provided between the female ball screw 41 and the ball 41.

The axial displacement of this female ball screw cylinder 33 is
Since the displacement side pulley piece 3 is transmitted to the displacement side pulley piece 3 via the first ball bearing 35 and the displacement side pulley piece 3 is displaced in the axial direction, the pulley width is changed. For example, if the displacement side pulley piece 3 is moved to the right in FIG. 1, the pulley width becomes narrow and the endless belt 45 is displaced to the outer diameter side. Therefore, when the pulley is on the primary side, the continuously variable transmission is on the speed increasing side, and when it is on the secondary side, it is on the decelerating side. On the other hand, if the displacement side pulley piece 3 is moved to the left in FIG. 1, the pulley width becomes wider and the endless belt 45 is displaced toward the inner diameter side. Therefore, when the pulley is on the primary side, the continuously variable transmission is on the deceleration side, and when it is on the secondary side, it is on the speed increasing side. As described above, in the case of the present invention, since the ball screw mechanism is used for the actuator 19 for displacing the displacement side pulley piece in the axial direction of the rotary shaft 1, the friction loss in the actuator 19 portion is reduced. Energy consumption can be reduced by reducing the transmission efficiency and improving the transmission efficiency.

Further, in the case of the present invention, the first ball bearing 35 and the second ball are provided on the inner peripheral surface of the distal end portion of the female ball screw cylinder 33 and the inner peripheral surface of the base end portion of the male ball screw cylinder 21. Since the outer ring raceways 36 and 24 forming the bearing 23 are directly formed, the female ball screw cylinder 33 and the male ball screw cylinder 2 are formed.
There is no need to fit a separate outer ring into the first unit. Therefore, the assembling work can be facilitated, and the dimensions of the respective predetermined parts, which are necessary when the separate outer ring is fitted and fixed to the female ball screw cylinder 33 and the male ball screw cylinder 21, are strictly regulated. Eliminate the need. Therefore, the cost of the entire pulley width adjusting device can be reduced in combination with the fact that the number of parts can be reduced by omitting the outer ring.

Moreover, each of the ball screw cylinders 3 may occur when the separate outer ring is internally fitted and fixed to a part of the female ball screw cylinder 33 or the male ball screw cylinder 21.
It is possible to prevent occurrence of damage such as wear due to relative sliding between the outer races 3 and 21 and ensure sufficient durability. Further, the diametrical direction of the part including the part of the female ball screw cylinder 33 and the first ball bearing 35, and the part including the part of the male ball screw cylinder 21 and the second ball bearing 23. Since the dimensions can be made smaller, the overall size and weight of the pulley width adjusting device for a continuously variable transmission can be reduced.

Next, FIG. 3 shows a second example of the embodiment of the present invention, which also corresponds to claims 1 and 2. In the case of this example, unlike the case of the above-mentioned first example, angular type bearings are used for the first and second ball bearings 35a, 23a. The ball bearings 35a and 23a are arranged in a state of having a predetermined contact angle. In the case of this example as described above, the thrust load that can be supported by each of the ball bearings 35a, 23a can be made larger than in the case of the above-described first example. The first ball bearing 35a is always subjected to a leftward thrust load in FIG. 3 due to the endless belt 45 pressing the inner surface of the displacement pulley piece 3. Therefore, it is not a particular problem that the first ball bearing 35a has a small thrust load in the reverse direction. The same applies to the second ball bearing 23a. Other configurations and operations are the same as in the case of the first example described above.

Next, FIG. 4 shows a third example of the embodiment of the present invention, which also corresponds to claims 1 and 2. In the case of this example, it is devised to prevent foreign matter from entering the inside of the ball screw mechanism of the actuator 19 and ensure excellent durability. That is, in the case of this example, the first dustproof member 46 is attached to the tip of the male ball screw cylinder 21 over the entire circumference. The outer diameter of the first dustproof member 46 is made larger than the outer diameter of the male ball screw cylinder 21, and its outer peripheral edge is slidably contacted with the inner peripheral surface of the intermediate portion of the female ball screw cylinder 33 over the entire circumference. ing. The first dustproof member 46 closes the gap between the outer peripheral surface of the male ball screw cylinder 21 and the inner peripheral surface of the intermediate portion of the female ball screw cylinder 33 over the entire circumference. Further, the female ball screw cylinder 33 is displaced in the axial direction in synchronization with the displacement side pulley piece 3 when changing the pulley width, but it is closest to the fixed side pulley piece 2 in order to make the pulley width the narrowest. Even in the state of being displaced in the direction (rightmost in FIG. 4), the outer peripheral edge of the first dustproof member 46 slides on the inner peripheral surface of the female ball screw cylinder 33 to the portion deviated from the female ball screw groove 40. In this way, the dimensions of each part are regulated.

On the other hand, the outer peripheral surface of the sleeve 44 externally fitted and fixed to the base end portion of the female ball screw cylinder 33, and the transmission case 1
A second dustproof member 47 is provided between the inner peripheral surface of the housing 2 and the inner peripheral surface of the housing portion 20 to close the gap between these peripheral surfaces over the entire circumference. For this reason, in the illustrated example, the second dustproof member 47 is locked in the locking groove formed at the opening-side end portion of the inner peripheral surface of the storage portion 20, and the inside of the second dustproof member 47 is locked. The peripheral edge is in sliding contact with the outer peripheral surface of the sleeve 44. Further, the female ball screw cylinder 33 is displaced in the axial direction in synchronization with the displacement side pulley piece 3 when changing the pulley width, but it is closest to the fixed side pulley piece 2 in order to make the pulley width the narrowest. The dimensions of the respective parts are regulated so that the base end part of the housing part 20 remains inserted even in the direction (rightmost in FIG. 4).

The first and second dustproof members 46, as described above,
The material 47 may be any material that can prevent the passage of foreign matter such as abrasion powder, and need not be oil-tight. Therefore, on condition that the passage of foreign matter can be blocked,
Various conventionally known materials can be used. For example, a fibrous material having fine passages inside, such as felt, allows the passage of air and blocks the passage of foreign matter. Therefore, the pressure in the space existing between the dustproof members 46 and 47 is reduced. Fluctuations can be suppressed. Therefore, the force required to displace the female ball screw cylinder 33 in the axial direction can be kept low. However, the first and second dustproof members 46,
47 may be a seal ring made of an elastic material such as an elastomer such as rubber.

Since the transmission case 12 is provided with an air supply / exhaust port (not shown) for suppressing a pressure change in the transmission case 12 due to a temperature change, dust and the like floating in the external space are not provided. Foreign matter may enter the transmission case 12. Further, metal abrasion powder and the like generated by abrasion of the components of the continuously variable transmission may still exist as foreign matter in the transmission case 12. And
The foreign matter entering the case 12 may adhere to the inner peripheral surface of the male ball screw cylinder 21 or the outer peripheral surface of the female ball screw cylinder 33. When the foreign matter thus adhered enters the parts where the balls 41, 41 constituting the ball screw mechanism are installed, the male and female ball screw grooves 32,
The surfaces of the balls 40 and the balls 41, 41 are scratched, resulting in poor durability such as defective operation and early peeling.

On the other hand, in the case of the present embodiment, the second dustproof member 47 is used to form a gap between the outer peripheral surface of the distal end portion of the female ball screw cylinder 33 and the inner peripheral surface of the accommodating portion 20. Since the ball 41 is closed, foreign matter attached to the outer peripheral surface of the female ball screw cylinder 33 does not enter the portion where the balls 41, 41 are installed. Further, since the space between the tip of the male ball screw cylinder 21 and the inner peripheral surface of the intermediate portion of the female ball screw cylinder 33 is closed by the first dustproof member 46, the inner circumference of the male ball screw cylinder 21 is closed. Foreign matter adhering to the surface of each ball 4
It does not go into the part where 1 and 41 are installed. Thus, since no foreign matter enters this part from any side, the surfaces of the male and female ball screw grooves 32, 40 and the balls 41, 41 are prevented from being scratched by foreign matter. The durability of the actuator 19 for driving the displacement side pulley piece 3 can be improved. Other configurations and operations are the same as in the case of the first example shown in FIGS.

In addition to the case of this example, a tubular member is fitted and fixed to the inner peripheral surface of the base end portion of the female ball screw cylinder 33, and
A first dustproof member 46 may be provided between the outer peripheral surface of the distal end portion of the tubular member and the inner peripheral surface of the distal end portion of the male ball screw cylinder 21. Further, it is difficult to prevent foreign matter from entering the portions where the balls 41, 41 are installed, from the outer peripheral surface side of the female ball screw cylinder 33 rather than from the inner peripheral surface side. Therefore, the first dustproof member 46 can be omitted if the entry of foreign matter from the inner peripheral surface side is not a particular problem. Alternatively, for the intrusion of foreign matter from the inner peripheral surface side, the first ball bearing 35 is of a sealed type with a seal plate and is rotated with the inner peripheral surface of the cylindrical portion 34 provided on the displacement side pulley piece 3. This can also be prevented by providing a dustproof member between the shaft 1 and the outer peripheral surface of the intermediate portion. Of course, in this case, the first dustproof member 46 can be omitted.

[0032]

Since the present invention is constructed and operates as described above, it is possible to inexpensively realize a pulley width adjusting device for a continuously variable transmission that is small and has high efficiency, and to use a belt type device for various purposes. It is possible to reduce the size and weight of the gear transmission and save energy at low cost.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing a first example of an embodiment of the present invention.

2 is a partially enlarged sectional view of FIG.

FIG. 3 is a cross-sectional view of a main part showing a second example of the embodiment of the present invention.

FIG. 4 is a sectional view of an essential part showing the third example.

FIG. 5 is a cross-sectional view of a main part showing a first example of a conventional structure.

[Explanation of symbols]

1 rotation axis 2 Fixed pulley 3 Displacement side pulley 4 rotating cylinder 5 First ball bearing 6 female screw 7 Fixed tube 8 male screw 9 Driven gear 10 drive shaft 11 drive gear 12 Transmission case 13 Second ball bearing 14 Third Ball Bearing 15 outer ring 16 outer ring 17 keys 18 keyway 19 actuators 20 Storage 21 Male Ball Screw Tube 22 Small diameter part 23 Second Ball Bearing 24 Outer ring track 25 inner ring 26 Step surface 27 annular member 28 Inner ring track 29 balls 30 Third ball bearing 31 Cylindrical space 32 Male ball screw groove 33 Female Ball Screw Tube 34 Cylindrical part 35 First Ball Bearing 36 Outer ring track 37 Inner ring 38 Step surface 39 Inner ring track 40 Female Ball Screw Groove 41 balls 42 holding hole 43 Circulation member 44 sleeve 45 endless belt 46 First dustproof member 47 Second dustproof member

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Claims (2)

[Claims] 1. In order to change the width of the pulley by incorporating it in a continuously variable transmission that changes the gear ratio between the drive shaft and the driven shaft by changing the width of the pulley around which a part of the endless belt is stretched. , A fixed pulley piece supported around the rotary shaft so as to freely rotate in synchronism with the rotary shaft while preventing axial displacement of the rotary shaft, and axial displacement of the rotary shaft. And a pulley width adjustment for a continuously variable transmission, which comprises a displacement side pulley piece rotatably supported in synchronization with the rotation shaft and an actuator for displacing the displacement side pulley piece in the axial direction of the rotation shaft. In this device, this actuator consists of a male ball screw cylinder fixed to the inside of the transmission case and having a male ball screw groove formed on the outer peripheral surface, and concentric with this male ball screw cylinder around this male ball screw cylinder. Placed in A female ball screw cylinder having a female ball screw groove formed on the inner peripheral surface thereof, a plurality of balls provided between the female ball screw groove and the male ball screw groove, and an inner peripheral surface of the distal end portion of the female ball screw cylinder. And a first rolling bearing provided between the outer peripheral surface of the cylindrical portion formed at the inner diameter side end of the displacement side pulley piece and capable of supporting a radial load and a thrust load. A pulley width adjusting device for a continuously variable transmission, characterized in that an outer ring raceway constituting the first rolling bearing is directly formed on an inner peripheral surface of a front end portion of a female ball screw cylinder. 2. In order to change the width of the pulley by incorporating it into a continuously variable transmission that changes the gear ratio between the drive shaft and the driven shaft by changing the width of the pulley around which a part of the endless belt is stretched. , A fixed pulley piece supported around the rotary shaft so as to freely rotate in synchronism with the rotary shaft while preventing axial displacement of the rotary shaft, and axial displacement of the rotary shaft. And a pulley width adjustment for a continuously variable transmission, which comprises a displacement side pulley piece rotatably supported in synchronization with the rotation shaft and an actuator for displacing the displacement side pulley piece in the axial direction of the rotation shaft. In this device, this actuator consists of a male ball screw cylinder fixed to the inside of the transmission case and having a male ball screw groove formed on the outer peripheral surface, and concentric with this male ball screw cylinder around this male ball screw cylinder. Placed in A female ball screw cylinder having a female ball screw groove formed on the inner peripheral surface thereof, a plurality of balls provided between the female ball screw groove and the male ball screw groove, and an inner peripheral surface of the distal end portion of the female ball screw cylinder. And a first rolling bearing provided between the outer peripheral surface of the cylindrical portion formed at the inner diameter side end of the displacement side pulley piece and capable of supporting a radial load and a thrust load. An outer ring raceway which constitutes a second rolling bearing for rotatably supporting the rotating shaft inside the transmission case is directly formed on the inner peripheral surface of the base end portion of the male ball screw cylinder. Pulley width adjustment device for variable speed transmission.