JP3284734B2 - Forward / backward switching device for continuously variable transmission and method of fixing sun gear and hub in this device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forward / reverse switching device for a continuously variable transmission and a method for fixing a sun gear and a hub in the device.

[0002]

2. Description of the Related Art As a conventional forward / reverse switching device of a continuously variable transmission, as shown in Japanese Patent Application No. 5-31338 filed by the present applicant, a set of a planetary gear unit and a forward clutch are disclosed. And a device having a reverse brake.
As shown in FIG. 6, in the forward / reverse switching device for a continuously variable transmission, as shown in FIG.
8 is provided on the end face of the sun gear 75 meshing with the forward clutch 4.
No. 0 hub 76 is integrally fixed by welding. The hub 76 has a drum-like shape and has a cylindrical portion extending in a direction away from the sun gear 75 on an outer peripheral portion. A spline is formed on the outer periphery of the cylindrical portion, and the clutch plate of the forward clutch 40 is formed on the spline. 73 and 74 are superimposed on each other.

An oil passage 104 is formed in the sun gear 75 so as to penetrate from the inner diameter to the outer diameter of the sun gear 75. An outlet of the oil passage 104 on the outer side of the sun gear has a gear portion 75a of the sun gear 75 and a hub 76. It is open between the joints.
The sun gear 75 has a hub 7 that penetrates through the oil passage 104.
An oil passage 130 that opens into the inner side of 6 is also formed. As a result, the oil supplied through the oil passage 104 and between the gear portion 75a and the hub coupling portion moves radially in the outer circumferential direction of the sun gear 75 due to the centrifugal force generated by the rotation of the sun gear 75, and Along with 75, the other planetary gear units are lubricated, and the clutch plates 73, 74 are lubricated along the rear surface 76a of the hub. The oil passage 130 is connected to the hub 76 via the oil passage 104.
The oil supplied to the inside of the clutch plates 73, 7
The lubrication of No. 4 is performed.

[0004]

However, the sun gear 75 is provided with the oil passages 104, 13 penetrating through the inside.
0, and a ring-shaped projection 75b for positioning the hub 76 before welding by fitting the inner diameter of the hub 76 to the end face thereof must be formed. .

The sun gear 75 and the hub 76 are usually
At present, a large amount of time is spent on welding preparation and welding work because they are fixed by electron beam welding.
Therefore, in the conventional apparatus, much time is required for manufacturing the sun gear 75, and much time is required for fixing the sun gear 75 and the hub 76. There is a problem of inviting.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a stepless step in which an oil path for lubricating oil to a planetary gear unit and a forward clutch can be easily formed and cost can be reduced. An object of the present invention is to provide a forward / reverse switching device of a transmission and a method of fixing a sun gear and a hub in the device.

[0007]

According to a first aspect of the present invention, there is provided a forward / reverse switching device for a continuously variable transmission, comprising a set of planetary gear units, a forward clutch and a reverse brake. The planetary gear device is provided between the input shaft of the starting mechanism and the sun gear, the internal gear, and a carrier that rotatably supports a pinion gear that meshes with both gears simultaneously. The null gear and the sun gear can be fastened or released, and the reverse brake allows the carrier to be fastened or released to the casing,
The internal gear is integrally rotatably connected to the input shaft via a drum of a forward clutch, and the sun gear is integrally connected to the output shaft of the continuously variable transmission mechanism. A hub having a fixed portion and a cylindrical portion in which the clutch plate of the forward clutch is continuously meshed with the outer periphery of the fixed portion is fixed, and the inner gear side of the sun gear connected to the output shaft is fixed. In the forward / reverse switching device of the continuously variable transmission to which lubricating oil is supplied, at least one continuous groove is formed on the end face of the sun gear continuously from the inner diameter part to the outer diameter part in the radial direction, The upper edge of the continuous groove is covered by joining the end face of the sun gear and the fixing portion of the hub, so that one opens at the inner diameter of the sun gear and the other opens at the outer diameter of the sun gear and the outer circumference of the hub. Only by a device which is characterized in that first oil passage opening is formed.

A forward / reverse switching device for a continuously variable transmission according to a second aspect of the present invention is the device according to the first aspect, wherein the sun gear extends radially to an end face of the sun gear and continues from the inner diameter portion to halfway of the end face. At least one notch groove is formed, and an oil hole communicating with the front and back surfaces is provided in a fixing portion of the hub, and the oil hole corresponds to the notch groove, and the end surface of the sun gear and the hub are fixed to each other. The upper edge of the notch groove is covered by joining with the portion, so that one opens at the inner diameter of the sun gear and the other opens toward the inside of the hub via the oil hole. Is formed.

According to a third aspect of the present invention, there is provided a method for fixing a sun gear and a hub in a forward / reverse switching device for a continuously variable transmission, comprising a set of planetary gear units, a forward clutch, and a reverse brake. An inner diameter portion of a sun gear constituting a planetary gear device is integrally connected to an output shaft of the continuously variable transmission mechanism, which is provided between the transmission mechanism and the input shaft, and supplies lubricating oil to the inner diameter side of the sun gear. is definitive in forward-reverse switching device of the continuously variable transmission is, the end face of the sun gear, clutch plates of the forward clutch is engaged to the outer peripheral edge contiguous with the substantially disc-shaped fixing portion from the outer circumference of the fixing part A method of fixing a sun gear and a hub that joins a hub having a cylindrical portion, wherein at least one continuous groove is formed on an end face of the sun gear continuously in a radial direction from an inner diameter portion to an outer diameter portion. , Sun gear end And the rear surface of the fixing portion abutting the hub,
A plurality of protrusions are provided at a predetermined interval, and the fixed portion abuts on the end surface of the sun gear so that the plurality of protrusions straddle the continuous groove, and the protrusion is crushed by projection welding to press the fixed portion on the end surface of the sun gear. And fixing the sun gear to the hub.

Further, the method of fixing the sun gear and the hub in the forward / reverse switching device for a continuously variable transmission according to a fourth aspect of the present invention is the method of the third aspect, wherein the sun gear extends radially to the end face of the sun gear from its inner diameter. At least one notch groove extending halfway through the end face is formed, an oil hole communicating with the front and back surfaces is provided in the fixing portion of the hub, and the oil hole corresponds to the notch groove, and the back surface of the fixing portion is formed. A plurality of projections provided on the end face of the hub, straddling the fixed portion to the end face of the sun gear while straddling between the continuous grooves formed on the end face of the hub, and crushing the projections by projection welding to the end face of the sun gear. A method of fixing a sun gear and a hub, wherein the fixing portion is pressed against the sun gear.

[0011]

According to the forward / reverse switching device of the continuously variable transmission according to the first aspect of the present invention, the sun gear passes through the first oil passage from the inner diameter to the outer diameter of the sun gear and the outer circumference of the hub. The oil that has flowed radially moves in the outer circumferential direction of the sun gear due to the centrifugal force generated by the rotation of the sun gear. That is, part of the oil lubricates the sun gear, pinion gear and internal gear, and the remaining part reaches the forward clutch along the back surface of the hub. Thereby, the planetary gear device and the forward clutch can be lubricated.

Further, the manufacture of the sun gear is completed only by forming a continuous groove on the end face thereof, and the first oil passage is formed by fixing the fixing portion of the hub to the end face of the sun gear. The unit price can be reduced. According to the forward / reverse switching device of the continuously variable transmission according to the second aspect, in addition to the above operation, the oil that has flowed into the hub through the second oil passage from the inner diameter portion of the sun gear, Along the inner surface of the hub, it reaches the forward clutch. Thereby, the forward clutch can be lubricated more efficiently.

According to a third aspect of the present invention, there is provided a method for fixing a sun gear and a hub in a forward / reverse switching device for a continuously variable transmission.
In addition to the effect of the first aspect, since the sun gear and the hub are fixed by projection welding, the work time spent for the fixing work is significantly reduced, and the cost of the continuously variable transmission is reduced. Further, according to the method of the fourth aspect, in addition to the above-described operation, it is easy to form the second oil passage through which the oil flows from the inner diameter portion of the sun gear into the hub.

[0014]

FIG. 1 shows a power transmission mechanism of a continuously variable transmission. The continuously variable transmission mechanism includes a torque converter (starting mechanism) 12, a forward / reverse switching mechanism 15, a V-belt type continuously variable transmission mechanism 29, and a differential device 56, and controls the rotation of the output shaft 10 of the engine to a predetermined speed. Differential device 5 in ratio and direction of rotation
6 drive shaft.

The torque converter 12 is provided with a lock-up mechanism, and controls the oil pressure in the lock-up oil chamber 12a so that the input side pump impeller 12b
And the output side turbine liner 12c can be mechanically connected or disconnected. The output shaft of the torque converter 12 is connected to the rotating shaft (input shaft) 13,
The rotating shaft 13 is connected to the forward / reverse switching mechanism 15.

The V-belt type continuously variable transmission mechanism 29 includes a driving pulley 16, a driven pulley 26, and a V-belt 24 that is communicably connected between the driving pulley 16 and the driven pulley 26. The drive shaft (output shaft) 14 includes a bearing 88
a and 88b rotatably supported by the casing 83. The drive pulley 16 is provided coaxially with the drive shaft 14, and is fixedly integrated with the drive shaft 14.
Rotates to form a V-shaped pulley groove that is disposed opposite to the fixed cone member 18 and that the drive pulley cylinder chamber 2
The movable cone member 22 can be moved in the axial direction of the drive shaft 14 by hydraulic pressure acting on zero. The driven pulley 26 has a driven shaft 28 whose axis is parallel to the drive shaft 14.
The fixed cone member 30 rotates integrally with the driven shaft 28, and is disposed opposite to the fixed cone member 30 to form a V-shaped pulley groove, and a hydraulic pressure acting on the driven pulley cylinder chamber 32. Movable cone member 3
4 is movable in the axial direction of the driven shaft 28. Then, V is formed in a pulley groove between the driving pulley 16 and the driven pulley 26.
The V-belt type continuously variable transmission mechanism 29 is configured by the belt 24 being communicably coupled.

In the differential gear 56, the drive gear 46 rotates integrally with the driven shaft 28, and the idler gear 48 meshes with the drive gear 46 that rotates integrally with the idler shaft 52. The pinion gear 54 rotates,
The pinion gear 54 and the final gear 44 mesh with each other. Next, the forward / reverse switching device 1 of the continuously variable transmission shown in FIG.
5 will be described in detail with reference to FIGS.

As shown in FIG. 2, the forward / reverse switching device 15 includes a planetary gear unit 19, a forward clutch 40, and a reverse brake 50. Planetary gear set 19
Is composed of a sun gear 75, an internal gear 77, a pinion gear 78, and a carrier 79. The sun gear 75 is spline-coupled to the drive shaft 14 rotatably supported by bearings 88a and 88b at a spline portion 75f of an inner diameter portion. The internal gear 77 is connected to the forward clutch drum 70 so as to be integrally rotatable, and the pinion gear 78 is
It is engaged with the internal gear 77 and the sun gear 75 while being rotatably supported by the carrier 79.

Further, the forward clutch drum 70 is spline-connected to the drive shaft 13. A piston 71 is fitted into the forward clutch drum 70, and an oil chamber 89 is provided between the drum 70 and the piston 71.
Is defined. Note that the piston 71 is always receiving a return force by the return spring 72. And
When the oil pressure is supplied to the oil chamber 89, the piston 71 causes the clutch plates 73 and 7 which are alternately superimposed.
4. A pressing force acts on 4. Then, the clutch plate 73 rotates integrally with the forward clutch drum 70,
The clutch plates 74 are spline-connected so as to rotate integrally with a hub 76 integrated with the sun gear 75.

The hub 7 integrated with the sun gear 75
Reference numeral 6 denotes a drum-shaped end face of the sun gear 75.
Disc-shaped fixing portion 7 fixed to surface 5c with surface contact
6a and a cylindrical portion 76b formed continuously from an edge of the fixing portion 76a and extending in a direction away from the sun gear 75.
It is composed of And, in the cylindrical portion 76b,
A spline that meshes with the clutch plate 74 is provided.

On the other hand, a carrier 79 rotatably supporting the pinion gear 78 has a disk-shaped wall portion 79a orthogonal to the axial direction, and is formed continuously from an edge of the wall portion 79a to form the forward clutch drum 70. Cylindrical part 7 surrounding the outer periphery
9b. A clutch plate 81 with an inner diameter spline is meshed with the outer periphery of the cylindrical portion 79b. The clutch plate 82 with the outer diameter spline, which is disposed alternately with the clutch plate 81 with the inner diameter spline, is provided.
Are engaged with splines 83a of the casing 83. The clutch plate 81 with the inner diameter spline and the clutch plate 8 with the outer diameter spline
2, the piston 84 of the reverse brake 50 is pressed.
The force is applied.

The reverse brake piston 84 is fitted in a cylinder 83b formed in a casing 83. An oil chamber 85 is defined between the reverse brake piston 84 and the cylinder 83b. Also,
The reverse brake piston 84 is always receiving a returning force by the spring 86. When the hydraulic pressure is supplied to the oil chamber 85, the reverse brake piston 84 causes the clutch plates 81 and 8 alternately superimposed.
2. A pressing force acts on 2.

A first thrust bearing 100 is disposed on the side facing the sun gear 75 on the inner diameter side of the carrier 79 between the sun gear 75 and the bearing 88, and a second thrust bearing is disposed on the side facing the bearing 88. 10
2 are provided respectively. Furthermore, the sun gear 75
Between the spline portion 75f and the inner diameter portion of the forward clutch drum 70, oil passes through an oil passage 120, an orifice 121, and an oil passage 122 formed in the forward clutch drum 70, which are connected to a hydraulic pressure source. It can be supplied.

Here, a plurality of grooves are formed in the end face 75c of the sun gear 75, and an oil passage is formed by fixing the fixing portion 76a of the hub 76 to the end face 75c by projection welding. That is,
3 (a), 3 which face the end face 75c of the sun gear 75.
As shown in FIG. 3B, which is a view taken along the line III-III in FIG. 3A, the sun gear 75 has an end face 75c cut in a radial direction with a predetermined width and depth to form an inner circumferential face 75d. From the outer peripheral surface 75
A continuous groove 140 that extends linearly up to e is formed. The two continuous grooves 140 are formed at symmetrical positions on the end face 75c.

The end face 75c between the continuous grooves 140, 140 has a predetermined width and depth from the inner peripheral face 75d.
The cutout groove 14 is cut in the radial direction halfway through the end face 75c.
2 are formed. This notched groove 142 also has the end face 75.
Two are formed at symmetrical positions of c. On the other hand, the fixing portion 76a of the hub 76 has the structure shown in FIGS. 4A, 4B, and 4C. 4A is a front view of the fixing portion 76a, FIG. 4B is a cross-sectional view taken along the line IV-IV of FIG.
FIG. 5C is a sectional view taken along the arrow VV in FIG. That is, a plurality of projections 144... For projection welding projecting toward the fixing surface (rear surface) 76 c are provided at predetermined positions in the fixing portion 76 a. And these projections 14
Between 4..., An oil hole 145 communicating from the fixing surface 76 c to the surface 76 d is formed.

Then, as shown in FIGS. 5A and 5B, with the oil hole 145 corresponding to the notch groove 142, the fixing surface 76 of the hub 76 is formed by projection welding.
a is fixed to the end face 75 a of the sun gear 75. Thus, the sun gear 75, since the upper portion of the continuous groove 140 is covered by the fixing portion 76a, the sun gear 75 spline
A first oil passage 150 penetrating from the line portion 75f to the gear portion 75a is formed. In addition, the notch groove 142 is
The second oil passage 152 penetrating from the spline portion 75f of the sun gear 75 toward the inner wall of the hub 76 is formed by being covered with the fixing portion 76a while corresponding to the hole 45.

Next, the operation of this embodiment will be described. First, at the time of forward travel, hydraulic pressure is supplied to an oil chamber 89 between the forward clutch drum 70 and the piston 71, while an oil chamber 85 between the cylinder 83b and the reverse brake piston 84 is drained. The forward clutch 40 is engaged, and the reverse brake 50 is released.
As a result, the clutch plate 73 and the clutch plate 74 are engaged by the frictional force, and the forward clutch drum 70 and the sun gear 75 are connected via the hub. On the other hand, since the internal gear 77 is always connected to the forward clutch drum 70, the internal gear 7
7 and sun gear 75 are both forward clutch drums 70
And rotate integrally. For this reason, the planetary gear device 19 is in a locked state and rotates integrally as a whole. Therefore, the rotation of the forward clutch drum 70 (that is, the rotation of the rotary shaft 13) is transmitted to the sun gear 75 as it is (that is, transmitted to the drive shaft 14 as it is). As a result, the rotating shaft 13 and the drive shaft 14 rotate integrally in the same direction, so that the spurs of the sun gear 75 pass through the oil passage 120, the orifice 121 and the oil passage 122.
The oil supplied between the in portion 75f and the inner diameter portion of the forward clutch drum 70 passes through the first oil passage 150 penetrating to the gear portion 75a, and connects the gear portion 75a of the sun gear 75 to the hub 76. And between the parts. The oil radially moves in the outer circumferential direction of the sun gear 75 due to the centrifugal force generated by the rotation of the sun gear 75. Thereby, oil is supplied to the planetary gear device 19. Further, since the oil flows along the rear surface of the hub 76 to the outer spline portion, the clutch plates 73 and 7 of the forward clutch 40 are moved.
4 is performed. In addition, some of the oil, described above through
Of the hub 76 from the spline portion 75f of the sun gear 75
The hub 7 passes through the second oil passage 152 penetrating toward the wall.
6, the lubrication of the clutch plates 73 and 74 of the forward clutch 40 is performed more efficiently.

Next, when the vehicle is set in the reverse traveling state, the oil chamber 89 of the forward clutch 40 is set in the drain state, and the hydraulic pressure is applied to the oil chamber 85 of the reverse brake 50. As a result, the reverse brake piston 84 is connected to the clutch plate 81 with the inner diameter spline and the clutch plate 8 with the outer diameter spline.
A pressing force acts on 2 to fix the carrier 79 to the casing 83. At this time, the internal gear 77 is always connected to the rotating shaft 13 via the forward clutch drum 70. Therefore, the internal gear 77 rotates in the same direction as the output shaft 10 of the engine. As described above, since the carrier 79 is fixed, the sun gear 75
Rotates in a direction opposite to the rotation direction of the internal gear 77. Therefore, the rotation of the rotation shaft 13
Rotation is in the opposite direction. Thereby, the reverse state is realized. In this case, the rotation of the drive shaft 14 is increased by the ratio of the number of teeth between the internal gear 77 and the sun gear 75.

At this time, the gear portion 75a of the sun gear 75 and the hub 7 pass through the first oil passage 150 similarly to the forward movement.
The oil is supplied to the joint of the second oil and the second oil.
As it passes through the path 152 and flows into the inner wall side of the hub 76,
Oil is supplied to the planetary gear device 19 and the forward clutch 40. Next, a method of fixing the sun gear 75 and the hub 76 will be described.

First, the notch groove 1 formed in the end face 75c
All other projections 134 contact the end face 75c while the oil hole 145 corresponds to the oil hole 42. Next, an electrode portion (not shown) of a projection welding apparatus having a flat electrode tip is brought into contact with the inner side (the inner surface 76d) of all the projections 144. Next, the projections 144 are formed on the end surfaces 75 by the electrode portions.
Each of the electrode portions is turned on in a state where the pressure is applied to the side c. As a result, all the projections 144... On which the current and the pressing force are concentrated are pressed against each other while being crushed, and the sun gear 75 and the hub 76 are integrally fixed.

Therefore, according to the forward / reverse switching device of the continuously variable transmission according to the present embodiment, the first portion penetrating from the spline portion 75f side of the sun gear 75 to the gear portion 75a side by the fixed portion 76a of the sun gear 75 and the hub 76. Since the oil passage 150 is formed, the oil supplied to the gear portion 75a through the first oil passage 150 efficiently lubricates the planetary gear device 19 and the forward clutch 40 with oil. Can be.

The notch groove 142 of the sun gear 75 and the oil hole 145 of the fixing portion 76a correspond to the sun gear 75.
The oil flows to the inner wall side of the hub 76 through the second oil passage 152 penetrating from the spline portion 75f side toward the inner wall of the hub 76, so that the lubrication of the clutch plates 73 and 74 of the forward clutch 40 is further improved. Can do well.

Further, in the present embodiment, the oil passages 104 and 130 penetrating through the sun gear 75 are not formed unlike the conventional apparatus, and the continuous groove 1 formed in the end face 75c of the sun gear 75 is not formed.
The first oil passage 150 is formed only by fixing the fixing portion 76a to the end face 76c so as to cover the upper part of the end face 40, while the end face 7
The oil hole 145 is made to correspond to the notch groove 142 formed in the groove 5c, and the fixing portion 76a covers the upper part of the oil hole 145 and the end face 76c.
, The second oil passage 152 is formed, so that the manufacturing cost of the sun gear 75 can be reduced. Moreover, since the sun gear 75 and the hub 76 can be integrally fixed by a short-time operation by projection welding, it is possible to realize a significant cost reduction of the continuously variable transmission.

In the embodiment, two continuous grooves 140 and two notch grooves 142 are formed in the end face 75c of the sun gear 75, and oil holes 145 are formed in the fixing portions 76a of the hub 76 so as to correspond to the notch grooves 142. Are formed, but the gist of the present invention is not limited to this.

[0035]

As described above, according to the forward / reverse switching device of the continuously variable transmission according to the first aspect of the present invention, the opening is formed toward the inner diameter of the sun gear, the outer diameter of the sun gear, and the outer circumference of the hub. By forming the first oil passage, the lubrication efficiency for the planetary gear device and the forward clutch can be improved.

The manufacture of the sun gear is completed only by forming a continuous groove on the end face thereof, and the first oil passage is formed by fixing the fixing portion of the hub to the end face of the sun gear. The unit price can be reduced.
Further, according to the forward / reverse switching device of the continuously variable transmission according to the second aspect, in addition to the above-described effects, the second oil passage that opens inside the inner portion of the sun gear and the hub is further formed. The forward clutch can be efficiently lubricated.

Further, according to the method for fixing the sun gear and the hub in the forward / reverse switching device of the continuously variable transmission according to the third aspect,
The lubrication efficiency of the planetary gear unit and the forward clutch can be increased, the production cost of the sun gear can be reduced, and the sun gear and the hub are fixed by projection welding, so the work required for the fixing work is The time is greatly reduced, and the cost of the continuously variable transmission can be reduced.

According to a fourth aspect of the present invention, in addition to the effect of the third aspect, the method of forming the second oil passage is facilitated, and the forward clutch is more efficiently lubricated. Can be.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a continuously variable transmission according to the present invention.

FIG. 2 is a sectional view of a main part showing a forward / reverse switching device of the continuously variable transmission according to the present invention.

FIG. 3 is a view showing a sun gear according to the present invention.

FIG. 4 is a view showing a fixing portion of a hub according to the present invention.

FIG. 5 is a diagram showing a fixed state of a sun gear and a fixed portion of a hub.

FIG. 6 is a diagram showing a conventional sun gear and hub fixed state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 13 Rotating shaft (input shaft) 14 Drive shaft (output shaft) 19 Planetary gear 29 Continuously variable transmission mechanism 40 Forward clutch 50 Reverse brake 75 Sun gear 75a Sun gear gear portion 75c Sun gear end surface 75d Sun gear inner peripheral surface 75e Sun gear Outer peripheral surface 140 Continuous groove 142 Notch groove 144 Projection 145 Oil hole 150 First oil path 152 Second oil path

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16H 37/02 F16H 57/04 F16H 57/08

Claims (4)

(57) [Claims] 1. A planetary gear set comprising a set of planetary gear units, a forward clutch and a reverse brake, disposed between a continuously variable transmission mechanism and an input shaft of a starting mechanism, the planetary gear unit includes a sun gear,
An internal gear and a carrier that rotatably supports a pinion gear that meshes with both gears at the same time. The forward clutch enables the internal gear and the sun gear to be fastened or released. Can be fastened or released to the internal gear,
The sun gear is integrally rotatably connected to the input shaft via a drum of a forward clutch, and the sun gear is integrally connected to the output shaft of the continuously variable transmission mechanism. A hub having a cylindrical portion in which the clutch plate of the forward clutch is continuously engaged from the outer periphery of the portion is fixed, and lubricating oil is provided on the inner diameter side of the sun gear connected to the output shaft. In the forward / reverse switching device of the continuously variable transmission being supplied, at least one continuous groove is formed in the end face of the sun gear continuously from the inner diameter part to the outer diameter part in the radial direction, and the end face of the sun gear and the end face of the sun gear are formed. The upper edge of the continuous groove is covered by joining with the fixed portion of the hub, so that one of the openings opens at the inner diameter of the sun gear and the other opens toward the outer diameter of the sun gear and the outer circumference of the hub. Reverse switching device before the continuously variable transmission, wherein a road is formed. 2. The forward / reverse switching device for a continuously variable transmission according to claim 1, wherein at least one notch groove is formed in an end face of the sun gear and extends radially and continues from an inner diameter portion to a middle of the end face. And an oil hole communicating with the front and back surfaces is provided in the fixing portion of the hub. The notch is formed by joining the end surface of the sun gear and the fixing portion of the hub with the oil hole corresponding to the notch groove. By covering the upper edge of the groove, a second oil passage is formed, one of which opens at the inner diameter of the sun gear and the other opens toward the inside of the hub via the oil hole. Forward / backward switching device for a continuously variable transmission. 3. A continuously variable transmission mechanism including a set of planetary gear units, a forward clutch, and a reverse brake, is disposed between the continuously variable transmission mechanism and the input shaft, and has a planetary gear connected to an output shaft of the continuously variable transmission mechanism. An inner surface of a sun gear constituting the device is integrally connected, and in a forward / reverse switching device of a continuously variable transmission in which lubricating oil is supplied to an inner diameter side of the sun gear, an end surface of the sun gear is substantially disc-shaped. A sun gear and a hub fixing method for joining a hub having a fixed portion and a cylindrical portion in which a clutch plate of a forward clutch is engaged with an outer peripheral edge continuously from the outer periphery of the fixed portion. On the end face, at least one continuous groove is formed continuously from the inner diameter part to the outer diameter part in the radial direction, and a plurality of projections are formed at predetermined intervals on the back surface of the fixed portion of the hub that contacts the end face of the sun gear. Provided, these multiple protrusions Forward / backward switching of the continuously variable transmission, wherein the fixed portion abuts on the end surface of the sun gear so that the ridge straddles the continuous groove, and the projection is crushed by projection welding to press the fixed portion on the end surface of the sun gear. How to fix the sun gear and hub in the device. 4. The method for fixing a sun gear and a hub in a forward / reverse switching device for a continuously variable transmission according to claim 3, wherein at least one of the ends of the sun gear extends radially and continues from the inner diameter portion to the middle of the end surface. A plurality of projections provided on the back surface of the fixing portion, wherein oil holes communicating with the front and back surfaces of the fixing portion of the hub are provided. The fixed portion is brought into contact with the end surface of the sun gear while straddling the continuous groove formed on the end surface of the hub, and the projection is crushed by projection welding to press the fixed portion on the end surface of the sun gear. A fixing method of a sun gear and a hub in a forward / reverse switching device of a continuously variable transmission.