EP0866929A1

EP0866929A1 - Continuously variable transmission with lubricating apparatus

Info

Publication number: EP0866929A1
Application number: EP97909695A
Authority: EP
Inventors: Daisuke Kobayashi
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 1996-11-05
Filing date: 1997-10-30
Publication date: 1998-09-30
Also published as: WO1998020269A1; KR20000004901A; JPH10141459A

Abstract

A continuously variable transmission including drive (1) and driven (2) pulleys rotatable about parallel axes. The drive pulleys (1) has a moveable drive pulley half (1c) axially moveable relative to a fixed drive pulley half (1b) to vary a first axial distance therebetween. The driven pulley (2) has a moveable drive pulley half (2c) axially moveable relative to a fixed driven pulley half (2b) to vary a second axial distance therebetween. The moveable pulley halves (1c, 2c) cooperate to vary the first and second axial distances in inverse proportion. A V-belt (3) drivingly connects the drive (1) and driven (2) pulleys. Two injector nozzles (10, 11) have outlets respectively open to two parallel and axially-offset hypothetical planes which extend perpendicularly to the axes through substantially a midpoint of a maximum of the first axial distance and a midpoint of a maximum of the second axial distance, respectively.

Description

DESCRIPTION

CONTINUOUSLY VARIABLE TRANSMISSION WITH LUBRICATING APPARATUS

The contents of Application No. 8-292763, with a filing date of November 5, 1996 in Japan, are hereby incorporated by reference. BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a continuously variable transmission (CVT) for a vehicle and, more specifically, to a CVT of a V-belt type which includes a lubricating apparatus .

Description of the Related Art

Continuously variable transmissions (CVTs) of a V-belt type are well known. Japanese Patent

Application First Publication No. 8-254260 discloses a CVT of such a V-belt type which has a lubricating apparatus . The apparatus includes a set of injector nozzles provided for injecting lubricating oil toward belt portions of a V-belt which are engaged with drive and driven pulleys, respectively. The belt portions are influenced by frictional heat caused by a relative slide movement of a ring and an element constituting the V-belt , on the drive and driven pulleys . The belt portions are cooled and lubricated by the lubricating oil injected from the corresponding injector nozzles. The injector nozzles have outlets open to substantially a common hypothetical plane perpendicular to mutually parallel axes of rotation of the drive and driven pulleys .

There is a demand for providing a CVT in which lubricating oil is surely and effectively injected to the belt portions of the V-belt which are engaged with the drive and driven pulleys , for the purposes of cooling and lubrication, even when the V-belt is moved in the axial direction of the drive and driven pulleys upon changing speed ratio of the CVT.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, there is provided a continuously variable transmission, comprising: a drive pulley rotatable about a first axis, the drive pulley including a fixed drive pulley half and a moveable drive pulley half axially moveable relative to the fixed drive pulley half to vary a first axial distance therebetween; a driven pulley rotatable about a second axis parallel to the first axis, the driven pulley including a fixed driven pulley half and a moveable driven pulley half axially moveable relative to the fixed driven pulley half to vary a second axial distance therebetween; the moveable drive pulley half and said moveable driven pulley half cooperating to vary the first and second axial distances in inverse proportion; a V-belt drivingly connecting the drive pulley to the driven pulley; and a first injector nozzle and a second injector nozzle adapted to inject lubricating oil to the V- belt, respectively; the first injector nozzle having an outlet open to a first hypothetical plane extending perpendicularly to the first axis through substantially a midpoint of a maximum of the first axial distance, while the second injector nozzle having an outlet open to a second hypothetical plane axially offset by a predetermined distance from the first hypothetical plane and extending perpendicularly to the second axis through substantially a midpoint of a maximum of the second axial distance; the first injector nozzle and the second injector nozzle being adapted to spray lubricating oil from the outlets onto the V-belt along the first and second hypothetical planes, respectively.

According to another aspect of the present invention, there is provided a continuously variable transmission, including a drive pulley rotatable about a first axis, the drive pulley including a fixed drive pulley half and a moveable drive pulley half axially moveable relative to the fixed drive pulley half to vary a first axial distance therebetween, a driven pulley rotatable about a second axis parallel to the first axis, the driven pulley including a fixed driven pulley half and a moveable driven pulley half axially moveable relative to the fixed driven pulley half to vary a second axial distance therebetween, the moveable drive pulley half and the moveable driven pulley half cooperating to vary the first and second axial distances in inverse proportion, a V-belt drivingly connecting the drive pulley to the driven pulley, first and second injector nozzles adapted to inject lubricating oil to the V-belt through outlets thereof, respectively, a hydraulic pump supplying a pressure of lubricating oil to the first and second injector nozzles, a pressure regulator fluidly connected to the hydraulic pump, the moveable drive pulley half, the moveable driven pulley half and the first and second injector nozzles, and a controller operatively coupled with the pressure regulator, the improvement wherein the outlet of the first injector nozzle is open to a first hypothetical plane extending perpendicularly to the first axis through substantially a midpoint of a maximum of the first axial distance, while the outlet of the second injector nozzle is open to a second hypothetical plane axially offset by a predetermined distance from the first hypothetical plane and extending perpendicularly to the second axis through substantially a midpoint of a maximum of the second axial distance; the first and second injector nozzles being adapted to spray lubricating oil from the outlets onto the V-belt along the first and second hypothetical planes, respectively.

According to still another aspect of the present invention, there is provided a lubricating apparatus for use in a continuously variable transmission including a drive pulley rotatable about a first axis, the drive pulley including a fixed drive pulley half and a moveable drive pulley half axially moveable relative to the fixed drive pulley half to vary a first axial distance therebetween, a driven pulley rotatable about a second axis parallel to the first axis, the driven pulley including a fixed driven pulley half and a moveable driven pulley half axially moveable relative to the fixed driven pulley half to vary a second axial distance therebetween, the moveable drive pulley half and the moveable driven pulley half cooperating to vary the first and second axial distances in inverse proportion, and a V-belt drivingly connecting the drive pulley to the driven pulley, comprising: a hydraulic pump feeding lubricating oil; a pressure regulator fluidly connected to the hydraulic pump to adjust a pressure of the lubricating oil; and a first injector nozzle and a second injector nozzle fluidly connected to the pressure regulator, respectively; the first injector nozzle having an outlet open to a first hypothetical plane extending perpendicularly to the first axis through substantially a midpoint of a maximum of the first axial distance, while the second injector nozzle having an outlet open to a second hypothetical plane axially offset by a predetermined distance from the first hypothetical plane and extending perpendicularly to the second axis through substantially a midpoint of a maximum of the second axial distance; the first injector nozzle and the second injector nozzle being adapted to spray the lubricating oil from the outlets onto the V-belt along the first and second hypothetical planes, respectively. BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic diagram showing a continuously variable transmission (CVT) of a V-belt type, of a first embodiment according to the present invention, which is incorporated in a transaxle drivingly connected to an engine;

Fig. 2 is an enlarged section of a V-belt, taken in a radial direction thereof; Fig. 3 is a fragmentary enlarged side view of the V-belt, as viewed in a circumferential direction thereof ;

Fig. 4 is a fragmentary enlarged longitudinal section of a main part of the CVT, taken in a longitudinal direction of the V-belt, showing a lubricating condition in a case where a speed ratio is maximum;

Fig. 5 is a fragmentary enlarged cross section as viewed in a direction perpendicular to the direction of Fig. 4;

Fig. 6 is a section similar to Fig. 4, but showing a lubricating condition in a case where the speed ratio is minimum; Fig. 7A is a fragmentary schematic side view of the V-belt tensioned on drive and driven pulleys, showing conditions of contact between a ring and an element in the case of the maximum speed ratio;

Fig. 7B is a fragmentary schematic side view similar to Fig. 7A, but showing conditions of contact between the ring and the element in the case of the minimum speed ratio;

Fig. 8 is a graph illustrating a relationship between the speed ratio and difference in speed between the ring and the element ;

Fig. 9 is a section similar to Fig. 4, but showing a main part of the CVT of a second embodiment according to the present invention; and

Fig. 10 is a section similar to Fig. 5, but showing the main part of the CVT of the second embodiment . DETAILED DESCRIPTION OF THE INVENTION

Referring to Figs. 1-6, a continuously variable transmission, referred to as CVT hereinafter, of a V-belt type, of a first embodiment according to the present invention, is now explained.

As illustrated in Fig. 1, the CVT includes a drive pulley 1 as input pulley, a driven pulley 2 as output pulley, and a V-belt 3 drivingly connecting the drive pulley 1 and the driven pulley 2. The drive pulley 1 includes a driver shaft la as input shaft, which is connected via a torque converter 4 and a clutch 5 to an output shaft 6a of an engine 6 to be rotatable about an axis . The drive pulley 1 is rotatable about the axis of rotation of the driver shaft la. The driver shaft la extends in one direction, i.e., left as viewed in Fig. 1, along the axis X. The drive pulley 1 includes a fixed drive pulley half lb securely connected to the driver shaft la and an axially moveable drive pulley half lc mounted to the driver shaft la in opposed spaced relation to the fixed drive pulley half lb to define therewith a drive pulley groove. The drive pulley halves lb and lc are of a generally frustoconical shape. The moveable drive pulley half lc is axially moveable relative to the fixed drive pulley half lb to vary an axial distance therebetween, i.e., a width of the drive pulley groove. The driven pulley 2 includes a follower shaft 2a rotatable about an axis parallel to the axis of the driver shaft la. The follower shaft 2a extends in an opposite direction, namely, right as viewed in Fig. 1, along the axis. The driven pulley 2 includes a fixed driven pulley half 2b securely connected to the follower shaft 2a and an axially moveable driven pulley half 2c mounted to the follower shaft 2a in opposed spaced relation to the fixed drive pulley half lb to define therewith a driven pulley groove. The driven pulley halves 2b and 2c are of a generally frustoconical shape. The moveable driven pulley half 2c is axially moveable relative to the fixed driven pulley half 2b to vary an axial distance therebetween, i.e., a width of the driven pulley groove. The fixed driven pulley half 2b is axially displaced by a predetermined distance from the fixed drive pulley half lb.

The moveable drive pulley half lc and the moveable driven pulley half 2c are operatively coupled to a pressure regulator 8 fluidly connected with a hydraulic pump 7. The pressure regulator 8 is operatively coupled with a controller 9 which develops a control signal for achieving a predetermined speed ratio corresponding to a predetermined shift pattern depending on operating condition of the vehicle. The term "speed ratio" is defined as a ratio of rotation speed of input shaft, i.e., the driver shaft la, of the CVT to rotation speed of output shaft, i.e., the follower shaft 2a, thereof. The pressure regulator 8 is operative in response to the control signal to apply fluid pressures to the moveable drive pulley half lc and the moveable driven pulley half 2c . The moveable pulley halves lc and 2c are hydraulically operated to move to the respective axial positions corresponding to the fluid pressures. Thus, the respective axial distances between the drive pulley halves lb and lc and between the driven pulley halves 2b and 2c are variable by the axial positions of the moveable drive pulley half lc and the moveable driven pulley half 2c.

The moveable drive pulley half lc and the moveable driven pulley half 2c cooperate to vary the respective axial distances from the fixed drive pulley half lb and the fixed driven pulley half 2b, in inverse proportion. The inversely proportional change of the axial distances between the drive pulley halves lb and lc and between the driven pulley halves 2b and 2c, alters a radius of curvature over which the V-belt 3 frictionally contacts with the pulley groove walls of the drive pulley 1 and the driven pulley 2. This causes change of the speed ratio of the CVT.

Specifically, the moveable drive pulley half lc siidably moves leftward as viewed in Fig. 1, away from the fixed drive pulley half lb to increase the axial distance therebetween, while the moveable driven pulley half 2c siidably moves leftward as viewed in Fig. 1, closer to the fixed driven pulley half 2b to reduce the axial distance therebetween. Namely, the radius of curvature over which the V- belt 3 frictionally contacts with the pulley groove walls of the drive pulley 1 decreases , while the radius of curvature over which the V-belt 3 frictionally contacts with the pulley groove walls of the driven pulley 2 increases. Therefore, the speed ratio becomes larger corresponding to a LOW shift range. When the axial distance between the drive pulley halves lb and lc is maximum and the axial distance between the driven pulley halves 2b and 2c is minimum, the speed ratio is maximum corresponding to the most LOW shift position. Conversely, when the moveable drive pulley half lc siidably moves toward the fixed drive pulley half lb to reduce the axial distance therebetween, the moveable driven pulley half 2c siidably moves apart from the fixed driven pulley half 2b to increase the axial distance therebetween. The radius of curvature over which the V-belt 3 frictionally contacts with the pulley groove walls of the drive pulley 1 increases , while the radius of curvature over which the V-belt 3 frictionally contacts with the pulley groove walls of the driven pulley 2 decreases. The speed ratio becomes smaller corresponding to a HIGH shift range. When the axial distance between the drive pulley halves lb and lc is smallest and the axial distance between the driven pulley halves 2b and 2c is greatest, the speed ratio is minimum corresponding to the most HIGH shift position.

The V-belt 3 has a structure as explained hereinafter. The V-belt is made of a suitable metal. As illustrated in Figs. 2 and 3, the V-belt 3 includes an endless ring 3a having a multi-layered structure, and a plurality of elements 3b mounted to the ring 3a. The elements 3b are continuously disposed in a circumferential direction of the ring 3a. Each of the elements 3b includes a protrudent portion having a generally triangular flat surface as shown in Fig. 2. The protrudent portion is connected with a leg-like portion tapered radially inward the ring 3a as shown in Fig. 3, through a central post portion interposed therebetween as shown in Fig. 2. Opposed slots are disposed adjacent the central post portion and extend parallel to each other in the circumferential direction of the ring 3a to be engaged with the ring 3a. As illustrated in Fig. 3, the leg-like portion has a vertical surface flush with the triangular flat surface of the protrudent portion, and a slant surface 3c inclined relative to the vertical surface. A boundary between the flat surface and the slant surface 3c is indicated by A in Fig. 3. Each element 3b is rotatable on the boundary A relative to the adjacent element 3b. The boundary A is arranged so as to be spaced radially inward by a distance r from a bearing surface B contacting a radial inner side of the ring 3a. For instance, the radial distance r may be approximately 1 mm. The provision of the slant surface 3c allows a row of the elements 3b to curve along the ring 3a on the radial inner side, causing the V-belt 3 to be wound on the drive pulley 1 and driven pulley 2. The leglike portion of the element 3b also has opposed side faces adjacent the slant surface 3c which are frictionally contacted with the respective pulley groove walls of the drive pulley 1 and the driven pulley 2 when the V-belt is mounted to the drive and driven pulleys 1 and 2. The V-belt 3 tensioned between the drive pulley 1 and the driven pulley 2 transmits a torque by the friction contact of the element 3b with the respective pulley groove walls of the drive and driven pulleys 1 and 2.

Referring back to Fig. 1, two separate injector nozzles 10 and 11 adapted to inject lubricating oil to the V-belt 3 are disposed in the vicinity of the drive pulley 1 and the driven pulley 2. The injector nozzles 10 and 11 are fluidly connected to the pressure regulator 8 via separate lubricating oil feed pipes 12 and 13, respectively. The injector nozzles 10 and 11 are provided for injecting the lubricating oil fed from the pressure regulator 8 to the V-belt engaged with the drive and driven pulleys 1 and 2 to thereby cool the V-belt . The injector nozzles 10 and 11 have outlets open to two hypothetical planes which are perpendicular to the axes of rotation of the drive and driven pulleys 1 and 2 and axially displaced by a predetermined distance from each other. One of the hypothetical planes extends through substantially a midpoint of a maximum of the axial distance between the fixed and moveable drive pulley halves lb and lc, and the other extends through substantially a midpoint of a maximum of the axial distance between the fixed and moveable driven pulley halves 2b and 2c. The injector nozzles are adapted to spray the lubricating oil from the outlets onto the V-belt along the hypothetical planes, respectively.

Specifically, as best shown in Fig. 4 in which the CVT is conditioned that the speed ratio is maximum, the injector nozzle 10 has the outlet open to a first hypothetical plane C extending perpendicularly to the axis of rotation of the drive pulley 1 through substantially the midpoint of the maximum axial distance between the fixed and moveable drive pulley halves lb and lc. When the V- belt 3 is placed in the position as shown in Fig. 4, the radius of curvature over which the V-belt 3 contacts with the drive pulley halves lb and lc is smallest for the maximum speed ratio as explained above. In this position, a center line of the V- belt 3 which extends in a longitudinal direction of the V-belt 3 is contained substantially in the first hypothetical plane C. The outlet of the injector nozzle 10 is thus directed to a central portion of the V-belt 3 which extends along the center line, and so designed as to spray the lubricating oil onto the central portion of the V-belt 3 along the first hypothetical plane C. On the other hand, the injector nozzle 11 has the outlet open to a second hypothetical plane C which is parallel to the first hypothetical plane C and axially offset by a predetermined distance δ from the first hypothetical plane C in such a manner as to be away from the fixed driven pulley half 2b, and extends through substantially the midpoint of the maximum axial distance between the fixed and moveable driven pulley halves 2b and 2c. The outlet of the injector nozzle 11 is so designed to spray the lubricating oil onto the V-belt 3 along the second hypothetical plane C. The outlet of the injector nozzle 11 is directed to the central portion of the V-belt 3 between the driven pulley halves 2b and 2c, when the V-belt 3 is placed in a position, as shown in Fig. 6, for the minimum speed ratio of the CVT as explained later.

As illustrated in Fig. 5, the injector nozzles 10 and 11 are disposed within an area defined by the drive pulley 1, the driven pulley 2 and the V-belt 3. The outlets of the injector nozzles 10 and 11 are arranged near an inner circumferential portion of the V-belt 3. Concretely, the outlet of the injector nozzle 10 is directed to near a belt portion 31 of the V-belt 3 which engages the fixed and moveable drive pulley halves lb and lc. The outlet of the injector nozzle 11 is directed to near a belt portion 32 of the V-belt 3 which engages the fixed and moveable driven pulley halves 2b and 2c. The outlets of the injector nozzles 10 and 11 are oriented in opposite directions as shown in Fig. 5, such that the lubricant oil is sprayed in the opposite directions.

Fig. 6 illustrates the drive pulley halves lb and lc, the driven pulley halves 2b and 2c and the V-belt 3 of the CVT conditioned to achieve the minimum speed ratio. In this condition, the V-belt 3 is placed in the position displaced axially and along the plane C from the position shown in Fig. 4. In this position, the radius of curvature over which the V-belt 3 contacts with the driven pulley halves 2b and 2c is smallest, and the center line of the V-belt 3 lies substantially in the second hypothetical plane C. The outlet of the injector nozzle 11 is thus directed to the central portion of the V-belt 3 and so designed as to spray the lubricating oil onto the central portion of the V- belt 3 along the second hypothetical plane C ' . A mechanism of heat generation in the V-belt 3 is now explained by referring to Figs. 7A and 7B. Figs . 7A and 7B illustrate fragmentary schematic side views showing conditions of the contact between the ring 3a and the element 3b of the V-belt 3 tensioned over the drive and driven pulleys 1 and 2 in the cases of the larger speed ratio and the smaller speed ratio. Point A, i.e., the boundary A, forms arc trajectories on the drive pulley 1 and the driven pulley 2 on the radial inner side of the V- belt 3, as shown in Fig. 7A. Point B, i.e., the bearing surface B, forms arc trajectories on the drive pulley 1 and the driven pulley 2 on the radial outer side of the V-belt 3, as shown in Fig. 7B. In the case of the larger speed ratio as illustrated in Fig. 7A, an angle of contact of the V-belt 3 with the drive pulley 1 is smaller than an angle of contact thereof with the driven pulley 2, and a length of the belt portion of the V-belt 3 which contacts with the drive pulley 1 is smaller than a length thereof contacting with the driven pulley 2. This is because the corresponding radius of curvature over the drive pulley 1 is smaller than the corresponding radius of curvature over the driven pulley 2. Accordingly, a frictional force caused between the ring 3a and the element 3b on the drive pulley 1 is smaller than a frictional force caused between those on the driven pulley 2. In addition, with the provision of the above-described radial distance r between the boundary A on the radial inner side of the V-belt 3 and the bearing surface B on the radial outer side thereof, an angular velocity of the ring 3a on the bearing surface B at the curvature of the V-belt 3 is smaller than an angular velocity of the element 3b at the curvature thereof . There is a difference in speed between the ring 3a and the element 3b as shown in Fig. 7A. For these reasons as described above, a relative slide movement between the ring 3a and the element 3b on the drive pulley 1 is caused. The relative slide movement causes frictional heat on the mutually contacting portions of the radial inner side surface of the ring 3a and the bearing surface B of the element 3b on the drive pulley 1. On the other hand, the ring 3a and the element 3b on the driven pulley 2 make a substantially unitary rotation so that the relative slide movement therebetween is not substantially caused.

Conversely, in the case of the smaller speed ratio as shown in Fig. 7B, an angle of contact of the V-belt 3 with the driven pulley 2 is smaller than that with the drive pulley 1. The frictional force caused between the ring 3a and the element 3b on the driven pulley 2 is smaller than the frictional force caused therebetween on the drive pulley 1. As a result, a relative slide movement between the ring 3a and the element 3b on the driven pulley 2 is caused, thus producing frictional heat on the mutually contacting portions of the ring 3a and the element 3b on the driven pulley 2.

Referring to Fig. 8, a relationship between the speed ratio of the CVT, referred to herein as CVT ratio, and difference in speed between the ring 3a and the element 3b of the V-belt 3 is explained.

Fig. 8 shows calculation results of the difference in speed between the ring 3a and the element 3b which is produced by changing the CVT ratio assuming that the V-belt 3 has an entire length of 700 mm, a distance between the driver shaft la and the follower shaft 2a is 160 mm, and a rotation speed of the driver shaft la is 4000 rpm.

As illustrated in Fig. 8, the difference in speed between the ring 3a and the element 3b is caused on the input pulley side, i.e., the drive pulley side, when the CVT ratio is larger than 1.0, while the difference in speed therebetween is caused on the output pulley side, i.e., the driven pulley side, when the CVT ratio is smaller than 1.0. It will be appreciated that as the CVT ratio becomes much larger or much smaller than 1.0, the difference in speed between the ring 3a and the element 3b and thus the relative slide movement therebetween increases, causing the larger frictional heat. In a case where the CVT ratio is maximum as shown in Fig. 4, frictional heat is produced on the belt portion of the V-belt 3 which is engaged with the drive pulley halves lb and lc. The outlet of the injector nozzle 10 is oriented to the belt portion which is influenced by the frictional heat and disposed substantially in the first hypothetical plane C. This arrangement of the outlet of the injector nozzle 10 assures that the lubricant oil is injected to the belt portion on the drive pulley 1 to thereby cool the belt portion frictionally heated and at the same time effectively lubricate the belt portion. The outlet of the injector nozzle 11 is axially offset by the predetermined distance δ , for instance 9.5 mm assuming the condition explained above by referring to Fig. 8. The lubricating oil is injected to the belt portion of the V-belt 3 which is engaged with the driven pulley 2 , in such a manner as axially offset by the predetermined distance δ from the central portion of the V-belt 3. In this circumstance, since the relative slide movement between the ring 3a and the element 3b on the driven pulley 2 is not substantially caused, the belt portion engaged with the driven pulley 2 is not influenced by frictional heat caused by the relative slide movement.

On the other hand, when the CVT ratio is minimum as shown in Fig. 6, frictional heat is produced on the belt portion of the V-belt 3 engaged with the driven pulley halves 2b and 2c. The outlet of the injector nozzle 11 is directed to the belt portion which is exposed to the frictional heat and disposed substantially in the second hypothetical plane C axially offset by the predetermined distance δ from the first hypothetical plane C.

Accordingly, it is assured that the lubricant oil is injected from the outlet of the injector nozzle 11 to the belt portion on the driven pulley 2 to cool the belt portion frictionally heated and effectively lubricate the belt portion. Meanwhile, on the drive pulley side, the relative slide movement between the ring 3a and the element 3b of the belt portion of the V-belt 3 which is engaged with the drive pulley 1 is not caused. Therefore, the belt portion on the drive pulley 1 is not exposed to frictional heat caused by the relative slide movement between the ring 3a and the element 3b.

Referring now to Figs. 9 and 10, the CVT of the second embodiment according to the invention is explained, which is similar to the CVT of the first embodiment except that injector nozzles 100 and 110 are connected with a common lubricating oil feed pipe 14. Like reference numerals and symbols denote like parts and therefore detailed explanations therefor are omitted.

Figs. 9 and 10 illustrate the condition of the drive pulley 1, the driven pulley 2 and the V-belt 3 in the case of the maximum speed ratio, as shown in Figs. 4 and 5.

As illustrated in Fig. 9, the injector nozzles 100 and 110 are coupled with the common lubricating oil feed pipe 14. The common lubricating oil feed pipe 14 is fluidly connected to the hydraulic pump 7 via the pressure regulator 8, as well as the lubricating oil feed pipes 12 and 13 of the first embodiment. The injector nozzles 100 and 110 are substantially same as the injector nozzles 10 and 11 of the first embodiment in otherwise structural features. Accordingly, in the case of the maximum speed ratio, an outlet of the injector nozzle 100 is open to the first hypothetical plane C extending through substantially the center line of the V-belt 3, and an outlet of the injector nozzle 110 is open to the second hypothetical plane C axially offset by the predetermined distance δ from the first hypothetical plane C. Then, the outlet of the injector nozzle 110 is axially displaced substantially by the predetermined distance δ from the center line of the V-belt 3.

As shown in Fig. 10, the injector nozzles 100 and 110 connected by the lubricating oil feed pipe 14 are concentratedly arranged in the area defined by the drive and driven pulleys 1 and 2 and the V- belt 3. The outlets of the injector nozzles 100 and 110 are oriented in substantially diametrically opposite directions so as to spray lubricating oil in the substantially diametrically opposite directions toward the belt portions of the V-belt 3 which are engaged with the drive and driven pulleys 1 and 2, respectively. This concentrated arrangement of the injector nozzles 100 and 110 serves for saving a space required for installing lubricating oil feed pipes , thereby providing a wide variety of design of the CVT.

In addition, as well as the arrangement of the first embodiment , the arrangement of the second embodiment can assure the injection of lubricating oil to the belt portion of the V-belt which is exposed to frictional heat caused in the CVT operation, facilitating cooling and lubricating of the V-belt and then increasing a performance of the CVT.

Claims

CLAIMS 1. A continuously variable transmission, comprising: a drive pulley rotatable about a first axis, said drive pulley including a fixed drive pulley half and a moveable drive pulley half axially moveable relative to the fixed drive pulley half to vary a first axial distance therebetween; a driven pulley rotatable about a second axis parallel to the first axis, said driven pulley including a fixed driven pulley half and a moveable driven pulley half axially moveable relative to the fixed driven pulley half to vary a second axial distance therebetween; said moveable drive pulley half and said moveable driven pulley half cooperating to vary the first and second axial distances in inverse proportion; a V-belt drivingly connecting the drive pulley to the driven pulley; and a first injector nozzle and a second injector nozzle adapted to inject lubricating oil to the V- belt, respectively; said first injector nozzle having an outlet open to a first hypothetical plane extending perpendicularly to the first axis through substantially a midpoint of a maximum of the first axial distance, while said second injector nozzle having an outlet open to a second hypothetical plane axially offset by a predetermined distance from the first hypothetical plane and extending perpendicularly to the second axis through substantially a midpoint of a maximum of the second axial distance; said first injector nozzle and said second injector nozzle being adapted to spray lubricating oil from the outlets onto the V-belt along the first and second hypothetical planes, respectively.

2. A continuously variable transmission as claimed in claim 1, wherein the first and second injector nozzles are disposed within an area defined by the drive pulley, the driven pulley and the V-belt.

3. A continuously variable transmission as claimed in claim 2, wherein the one outlet of the first injector nozzle is directed to near a belt portion of the V-belt which engages the fixed drive pulley half and the moveable drive pulley half, while the outlet of the second injector nozzle is directed to near a belt portion of the V-belt which engages the fixed driven pulley half and the moveable driven pulley half .

4. A continuously variable transmission as claimed in claim 3, wherein the outlets of the first and second injector nozzles are oriented in opposite directions .

5. A continuously variable transmission as claimed in claim 1, wherein the first and second injector nozzles are connected with separate lubricating oil feed pipes, respectively.

6. A continuously variable transmission as claimed in claim 1, wherein the first and second injector nozzles are connected with a common lubricating oil feed pipe.

7. A continuously variable transmission as claimed in claim 1, wherein the drive pulley comprises a driver shaft connected to the fixed drive pulley half and extending in one direction along the first axis to permit sliding movement of the moveable drive pulley half thereon, and the driven pulley comprises a follower shaft connected to the fixed driven pulley half and extending in an opposite direction along the second axis to permit sliding movement of the moveable driven pulley half thereon, the fixed driven pulley half being offset by a predetermined axial distance from the fixed drive pulley half.

8. A continuously variable transmission as claimed in claim 1, further comprising a hydraulic pump and a pressure regulator which is fluidly connected to the hydraulic pump, the moveable drive pulley half, the moveable driven pulley half and the first and second injector nozzles.

9. A continuously variable transmission as claimed in claim 8 , further comprising a controller operatively coupled with the pressure regulator to establish a predetermined speed ratio of rotation speed of the drive pulley to rotation speed of the driven pulley.

10. A continuously variable transmission, including a drive pulley rotatable about a first axis, said drive pulley including a fixed drive pulley half and a moveable drive pulley half axially moveable relative to the fixed drive pulley half to vary a first axial distance therebetween, a driven pulley rotatable about a second axis parallel to the first axis , said driven pulley including a fixed driven pulley half and a moveable driven pulley half axially moveable relative to the fixed driven pulley half to vary a second axial distance therebetween, said moveable drive pulley half and said moveable driven pulley half cooperating to vary the first and second axial distances in inverse proportion, a V- belt drivingly connecting the drive pulley to the driven pulley, first and second injector nozzles adapted to inject lubricating oil to the V-belt through outlets thereof, respectively, a hydraulic pump supplying a pressure of lubricating oil to the first and second injector nozzles, a pressure regulator fluidly connected to the hydraulic pump, the moveable drive pulley half, the moveable driven pulley half and the first and second injector nozzles, and a controller operatively coupled with the pressure regulator, the improvement wherein the outlet of the first injector nozzle is open to a first hypothetical plane extending perpendicularly to the first axis through substantially a midpoint of a maximum of the first axial distance, while the outlet of the second injector nozzle is open to a second hypothetical plane axially offset by a predetermined distance from the first hypothetical plane and extending perpendicularly to the second axis through substantially a midpoint of a maximum of the second axial distance; said first and second injector nozzles being adapted to spray lubricating oil from the outlets onto the V-belt along the first and second hypothetical planes, respectively.

11. A lubricating apparatus for use in a continuously variable transmission including a drive pulley rotatable about a first axis, said drive pulley including a fixed drive pulley half and a moveable drive pulley half axially moveable relative to the fixed drive pulley half to vary a first axial distance therebetween, a driven pulley rotatable about a second axis parallel to the first axis, said driven pulley including a fixed driven pulley half and a moveable driven pulley half axially moveable relative to the fixed driven pulley half to vary a second axial distance therebetween, said moveable drive pulley half and said moveable driven pulley half cooperating to vary the first and second axial distances in inverse proportion, and a V-belt drivingly connecting the drive pulley to the driven pulley, comprising: a hydraulic pump feeding lubricating oil; a pressure regulator fluidly connected to said hydraulic pump to adjust a pressure of the lubricating oil; and a first injector nozzle and a second injector nozzle fluidly connected to said pressure regulator, respectively; said first injector nozzle having an outlet open to a first hypothetical plane extending perpendicularly to the first axis through substantially a midpoint of a maximum of the first axial distance, while said second injector nozzle having an outlet open to a second hypothetical plane axially offset by a predetermined distance from the first hypothetical plane and extending perpendicularly to the second axis through substantially a midpoint of a maximum of the second axial distance; said first injector nozzle and said second injector nozzle being adapted to spray the lubricating oil from the outlets onto the V-belt along the first and second hypothetical planes, respectively.

12. A lubricating apparatus as claimed in claim 11, wherein the first and second injector nozzles are disposed within an area defined by the drive pulley, the driven pulley and the V-belt .

13. A lubricating apparatus as claimed in claim 12, wherein the outlet of the first injector nozzle is directed to near a belt portion of the V-belt which engages the fixed drive pulley half and the moveable drive pulley half, while the outlet of the second injector nozzle is directed to near a belt portion of the V-belt which engages the fixed driven pulley half and the moveable driven pulley half .

14. A lubricating apparatus as claimed in claim 13, wherein the outlets of the first and second injector nozzles are oriented in opposite directions.

15. A lubricating apparatus as claimed in claim 11, wherein the first and second injector nozzles are connected with separate lubricating oil feed pipes, respectively, which are connected to the pressure regulator.

16. A lubricating apparatus as claimed in claim 11, wherein the first and second injector nozzles are connected with a common lubricating oil feed pipe connected to the pressure regulator.

17. A lubricating apparatus as claimed in claim 11, wherein said pressure regulator is fluidly connected to the moveable drive pulley half and the moveable driven pulley half.