JP2001349332A - Fixed constant velocity universal joint and assembly method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily increase the strength of a cage when the maximum operation angle is further increased. SOLUTION: In a fixed constant velocity universal joint provided with a joint outer ring 25 forming a plurality of track grooves 22, a joint inner ring 28 forming a plurality of track grooves 27, a ball 29 provided between both track grooves 22 and 27 of the joint inner and outer rings 28, 25, and the cage 30 holding the ball 29 between the joint inner and outer rings 28 and 25, they are set to satisfy the following conditions: f/(f+F)=0.35 or more when (f+F)/ PCR=0.1, f/(f+F)=0.11 or more when (f+F)/PCR=0.2, and f/(f+F)=0.03 or more when (f+F)/PCR)=0.3 when a track offset amount is F, a cage offset amount is f, and a length of a line segment joining a center O2 of a curvature of the track groove 27 of the joint inner ring 28 with a center of the ball is PCR.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixed type constant velocity universal joint and, more particularly, to a fixed type constant velocity universal joint used in a power transmission system of an automobile or various industrial machines. The present invention relates to a fixed type constant velocity universal joint that allows only a fixed velocity universal joint.

[0002]

2. Description of the Related Art As a fixed type constant velocity universal joint, for example, there is a UF (undercut free) type as shown in FIG. This fixed type constant velocity universal joint includes a joint outer ring 5 having a mouth portion 4 in which a plurality of track grooves 2 are formed on an inner spherical surface 1 at circumferentially equal intervals along an axial direction toward an open end 3.
And a joint inner ring 8 in which a plurality of track grooves 7 paired with the track groove 2 of the joint outer ring 5 are formed in the outer spherical surface 6 at equal intervals in the circumferential direction along the axial direction, and both the joint outer ring 5 and the joint inner ring 8 A plurality of balls 9 interposed between the track grooves 2 and 7 for transmitting torque, an inner spherical surface 1 of the joint outer race 5 and an outer spherical surface 6 of the joint inner race 8
And a cage 10 interposed between them to hold each ball 9. The plurality of balls 9 are accommodated in pockets 13 formed in the cage 10 and are arranged at regular intervals in the circumferential direction.

[0003] For example, a driven rotary shaft is connected to a stem portion (not shown) of the joint outer ring 5 extending integrally from the mouth portion 4, and a drive rotary shaft is connected to the joint inner ring 8 by serration or the like. By doing so, a structure is possible in which torque transmission can be performed while allowing an operating angle displacement between the two rotating shafts.

In this fixed type constant velocity universal joint, the center of curvature O ₁ ′ of the track groove 2 of the outer ring 5 of the joint and the center O ₂ of curvature of the track groove 7 of the inner ring 8 of the joint have a structure capable of obtaining a large operating angle. 'Is offset in the axial direction in the opposite direction to the joint center plane P' including the ball center by an equal distance F '(track offset). Similarly, the center of curvature O ₃ ′ of the inner spherical surface 11 of the cage 10 and the center of curvature O ₄ ′ of the outer spherical surface 12 are axially oppositely offset by the same distance f ′ from the joint center plane P ′. (Cage offset).

In this conventional fixed type constant velocity universal joint, the cage offset amount f 'and the total offset amount (f' + F ')
[Cage offset amount f 'and track offset amount F'
Is set so as to satisfy the following condition.
However, the cage offset amount f 'and the total offset amount (f'
Since the optimum range of the ratio to (+ F ′) varies depending on the size of the joint, it is necessary to determine the ratio in relation to the basic dimensions representing the size of the joint. Therefore, the total offset amount (f ′
+ F ′), the length PCR ′ of the line segment connecting the center of curvature O ₂ ′ of the track groove 7 of the joint inner ring 8 (or the center of curvature O ₁ ′ of the track groove 2 of the joint outer ring 5) and the center of the ball 9.
When the ratio of the cage offset amount f ′ to the total offset amount (f ′ + F ′) is expressed as (f ′ + F ′) / PCR ′ = 0.14, f ′ /
(F ′ + F ′) = 0 (f ′ + F ′) / When PCR ′ = 0.15, f ′ / F ′
It is set so as to satisfy the condition of (f ′ + F ′) = 0.11.

[0006]

By the way, in the conventional fixed type constant velocity universal joint, the dimensions and shape are such that the ratio of the cage offset amount f 'to the total offset amount (f' + F ') satisfies the above-mentioned condition. Since the ball 9 was designed, the ball 9 was incorporated in the following manner.

First, with the joint inner ring 8 and the cage 10 incorporated in the joint outer ring 5, the track groove 2 of the joint outer ring 5, the pocket 13 of the cage 10 and the track groove 7 of the joint inner ring 8 are assembled as shown in FIG. After positioning in the radial direction,
The cage 10 and the joint inner ring 8 are tilted in the axial direction with respect to the joint outer ring 5 such that the gap between the open end 3 of the joint outer ring 5 and the entrance end of the pocket 13 of the cage 10 is larger than the ball diameter.

Thus, the pocket 13 of the cage 10
One of them is exposed outward from the open end 3 of the joint outer ring 5, and the ball 9 is inserted from the gap between the open end 3 of the joint outer ring 5 and the entrance end of the pocket 13 of the cage 10, and in the manner described above. Then, the balls 9 are sequentially inserted into the remaining pockets 13. Then, when assembling the last ball 9, as shown in FIG. 6, the angle at which the ball 9 is incorporated is in the phase of φ = 0 °, that is, from the direction coinciding with the direction connecting the center of the pocket 13 and the center of the cage 10. Ball 9 in pocket 13
To be inserted into.

When the last ball 9 is inserted, the outer ring 5
The cage 10 is tilted in the axial direction, so that the ball 9 having a curvature in the axial direction at the back side of the joint outer ring 5, that is, the balls 9 in the phases of φ = 120 ° and 240 ° move in the circumferential direction. It moves and interferes with the end of the pocket 13. If the circumferential dimension of the pocket 13 is increased, interference at the time of assembling can be suppressed.
Since the width of the pillar portion 14 between the pockets 13 is reduced, the strength of the cage 10 is reduced. Conversely, when the circumferential dimension of the pocket 13 is reduced, the column 1
Since the width of 4 can be increased, the strength of the cage 10 can be improved, but it is difficult to suppress the interference at the time of assembling.

Therefore, the pocket 1 in the cage 10
The circumferential dimension of 3 must be set in consideration of the cage strength so that there is no interference due to the circumferential movement of other balls 9 when the operating angle is set when the balls 9 are assembled. Thus, there has been a demand that the cage 10 be easily strengthened without interference due to the circumferential movement of the ball 9.

Therefore, the present invention has been proposed in view of the above problems, and an object of the present invention is to realize a further increase in the maximum operating angle and to suppress interference when the ball is assembled. Another object of the present invention is to provide a fixed type constant velocity universal joint which can easily increase the strength of a cage and a method of assembling the same.

[0012]

According to a first aspect of the present invention, a plurality of track grooves are formed on an inner spherical surface along an axial direction at equal intervals in a circumferential direction. The joint outer ring formed toward the outer ring, a plurality of track grooves forming a pair with the track groove of the joint outer ring on the outer spherical surface are formed along the axial direction at equal intervals in the circumferential direction, and the joint outer ring and the joint inner ring A fixed type constant velocity universal joint including a plurality of balls interposed between both track grooves to transmit torque, and a cage interposed between an inner spherical surface of the joint outer ring and an outer spherical surface of the joint inner ring to hold the balls. In, the center of curvature of the track groove of the joint outer ring and the center of curvature of the track groove of the joint inner ring are offset by the same distance in the axial direction with respect to the joint center plane including the ball center, and With the center of the outer sphere of the cage The spherical center is offset to the opposite side by an equal distance in the axial direction with respect to the joint center plane, the track offset amount is F, the cage offset amount is f, the center of curvature of the track groove of the joint outer ring or the joint inner ring. When the length of a line segment connecting the center of curvature of the track groove and the center of the ball is represented by PCR, when (f + F) /PCR=0.1, f / (f + F) =
0.35 or more When (f + F) /PCR=0.2, f / (f + F) =
0.1 / or more, when (f + F) /PCR=0.3, f / (f + F) =
It is characterized by being set so as to satisfy the condition of 0.03 or more.

According to a fourth aspect of the present invention, the components of the fixed type constant velocity universal joint according to the first aspect of the present invention include a track offset amount F, a cage offset amount f,
And a fixed type constant velocity universal joint in which the length PCR of the line segment connecting the center of curvature of the track groove of the outer ring of the joint or the center of curvature of the track groove of the inner ring of the joint with the center of the ball satisfies the above condition. In incorporating the last ball into the pocket of the cage, the ball is inserted from a direction forming a predetermined phase angle with respect to a cage radial direction passing through the center of the pocket.

According to the first aspect of the present invention, the relationship between the track offset amount F and the length of a line segment PCR connecting the center of curvature of the track groove of the outer ring of the joint or the center of curvature of the track groove of the inner ring of the joint and the center of the ball. By setting the offset amount f so as to satisfy the above condition, the maximum operating angle can be increased.

In order to realize a higher maximum operating angle,
As in the invention of claim 4, when the last ball is assembled,
By inserting the ball from a direction that forms a predetermined phase angle with respect to the cage radial direction passing through the center of the pocket, the interference angle between the ball on the back side of the already installed joint outer ring and the column between the cage pocket is conventionally Can be larger than in the case of Therefore, when the last ball is inserted, the amount of circumferential movement of the ball on the track side having a curvature in the axial direction on the back side of the joint outer ring becomes smaller than in the conventional case, so that the column width between the cage pockets is reduced. Can be set large and the strength of the cage can be easily increased.

Further, when the ball is assembled, the ball is not positioned 180 ° opposite to the ball insertion side in the cage radial direction, so that the axial length of the track groove is not required. The length in the direction can be reduced, and the entire assembly can be made compact.

The invention according to claims 2 and 5 is characterized in that the number of the balls is eight. As a result, the load applied to one ball can be reduced and the efficiency can be improved, and the strength, load torque, and durability are excellent. The ball diameter can be reduced, and the entire joint can be reduced in size. It is. The invention according to claims 3 and 6 is characterized in that a pocket gap is formed so as not to restrain the ball on the back side of the pocket of the cage. In this way, even if the depth of the cage on the back side is reduced due to the increase in the cage offset amount, the strength of the cage can be ensured.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fixed type constant velocity universal joint according to the present invention will be described in detail below.

The fixed type constant velocity universal joint of the embodiment shown in FIG. 1 has a mouth portion 24 in which a plurality of track grooves 22 are formed on an inner spherical surface 21 at equal intervals in a circumferential direction toward an open end 23 along an axial direction. Outer race 25 having a plurality of track grooves 27 forming a pair with the track groove 22 of the joint outer race 25 on the outer spherical surface 26.
Inner ring 2 formed along the axial direction at equal intervals in the circumferential direction
8, both track grooves 2 of the joint outer ring 25 and the joint inner ring 28
Plural balls 2 that transmit torque by being interposed between 2 and 27
9 and a cage 30 that holds each ball 29 between the inner spherical surface 21 of the joint outer race 25 and the outer spherical surface 26 of the joint inner race 28. The plurality of balls 29
And are arranged at equal intervals in the circumferential direction.

A driven-side rotating shaft, for example, is connected to a stem portion (not shown) extending integrally from the mouth portion 24 of the joint outer ring 25, and a driving-side rotating shaft is connected to the joint inner ring 28 by serration or the like. By doing so, a structure is possible in which torque transmission can be performed while allowing an operating angle displacement between the two rotating shafts.

Each track groove 22 of the joint outer race 25 has a tapered shape in which the groove bottom on the opening side is linearly enlarged toward the opening end. That is, the track groove 22 has an arcuate bottom 22a on the back side of the mouth part 24 and a tapered bottom 22b on the opening side of the mouth part 24. On the other hand, the joint inner ring 28
Each of the track grooves 27 has a tapered shape in which the bottom of the back groove is linearly enlarged toward the back. That is, the track groove 27 is formed in the circular arc bottom 27a on the opening side of the mouse portion 24.
And a tapered bottom 27 b on the back side of the mouth part 24.

As described above, by forming the groove bottom on the opening side of the track groove 22 of the mouth portion 24 of the joint outer ring 25 as the tapered bottom 22b whose diameter is linearly increased toward the opening end, the mouth portion 24 of the joint outer ring 25 is formed. Without increasing the outside diameter of
The maximum operating angle has been increased. As a result, the joint outer ring 25 can be made compact, the load capacity can be increased, and the like.

Although not shown, the axial shape of the track groove 22 of the joint outer ring 25 may be all straight tapered. That is, as the track groove 22 of the joint outer race 25, a straight tapered bottom that uniformly increases in diameter from the back side of the mouth portion 24 toward the opening end 23 thereof may be formed. Also, the track groove 27 of the joint inner ring 28
Alternatively, a straight tapered bottom that uniformly increases in diameter from the opening side of the mouth portion 24 to the back side thereof may be formed. By doing so, it is possible to improve the workability by, for example, cold forging as well as to increase the maximum operating angle.

In the fixed type constant velocity universal joint shown in FIG.
25 center of curvature O of the track groove 22 ₁And the joint inner ring 28
Center of curvature O of the track groove 27_TwoIncludes the center of the ball
In the axial direction opposite to the joint center plane P by the same distance F
Offset (track offset). As well
The center of curvature O of the inner spherical surface 31 of the cage 30_ThreeAnd the outer sphere
32 center of curvature O_FourIs equal to the joint center plane P
Is offset in the opposite direction in the axial direction by a distance f (case
Offset).

In the fixed type constant velocity universal joint of this embodiment,
Structure that can take a larger operating angle than the conventional type
Therefore, the cage offset amount f and the total offset amount
The ratio with (f + F) is set so as to satisfy the following condition.
You. However, the cage offset amount f and the total offset amount (f
+ F) depends on the size of the joint
Therefore, in relation to the basic dimensions representing the size of the joint,
Need to ask. Therefore, the total offset amount (f +
F) and the center of curvature O of the track groove 27 of the joint inner ring 28. _Two
(Or center of curvature of track groove 22 of joint outer ring 25)
O₁) And the center of the ball 29, the length PCR of the line segment
The cage offset f and the total offset according to the ratio of
When the ratio to (f + F) is (f + F) /PCR=0.1, f / (f + F) =
0.35 or more When (f + F) /PCR=0.2, f / (f + F) =
0.1 / or more, when (f + F) /PCR=0.3, f / (f + F) =
Set to satisfy the condition of 0.03 or more.

In the embodiment shown in FIG. 1, when the track offset amount F = 0, that is, f / (f + F) =
The case of 1.0 is shown. Therefore, the center of curvature O ₁ of the track groove 22 of the joint outer ring 25 matches the center of curvature O ₄ of the outer spherical surface 32 of the cage 30, and the center of curvature O ₂ of the track groove 27 of the joint inner ring 28 is It is located coincident with the center of curvature O ₃ of the inner spherical surface 31.

As described above, the total offset amount (f +
F) and the center of curvature O ₁ of the track groove 22 of the joint outer ring 25.
Alternatively, according to the ratio of the length PCR of the line segment connecting the center of curvature O ₂ of the track groove 27 of the joint inner ring 28 to the center of the ball,
By setting the ratio of the cage offset amount f to the total offset amount (f + F) so as to satisfy the above condition, it is possible to realize a higher maximum operating angle than the conventional type.

As described above, in the fixed type constant velocity universal joint according to the embodiment in which the maximum operating angle is further increased, the ratio between the cage offset amount f and the total offset amount (f + F) satisfies the above condition. Ball 2
It is effective to incorporate 9 in the following manner.

As before, the joint outer ring 25 and the joint inner ring 28
With the cage 30 incorporated and the track groove 22 of the joint outer race 25, the pocket 33 of the cage 30 and the track groove 27 of the joint inner race 28 radially aligned, the open end 23 of the joint outer race 25 and the cage are aligned. The cage 30 and the joint inner ring 28 are inclined in the axial direction with respect to the joint outer ring 25 so that a gap between the pocket 30 and the inlet end of the pocket 33 is larger than the ball diameter. In this way, cage 3
0 of the pocket 33 of the joint 30 faces outward from the open end 23 of the joint outer ring 25, and the ball 2 is inserted through the gap between the open end 23 of the joint outer ring 25 and the entrance end of the pocket 33 of the cage 30.
Insert 9 The remaining pockets 33 in the manner described above
Balls 29 are sequentially inserted into the holes.

When the last ball 29 is assembled, as shown in FIG. 2, a predetermined phase angle with respect to the cage radial direction passing through the center of the pocket 33 of the cage 30;
The ball 29 is inserted into the pocket 33 from a direction of ± 30 °, that is, φ = 30 ° or 330 °. That is, in the state where the direction connecting the center of the pocket 33 into which the last ball 29 is to be incorporated and the center of the cage 30 is φ = ± 30 °, that is, the cage 30 is arranged in a phase of φ = 30 ° or 330 °, The ball 29 is inserted into the pocket 33 along the cage radial direction.

In this manner, the angle of interference between the ball 29 on the inner side of the joint outer race 25 already assembled and the column 34 between the pockets 33 of the cage 30 can be made larger than in the conventional case. Therefore, the last ball 2
9 is inserted, the track side having a curvature in the axial direction on the back side of the joint outer ring 25, that is, φ = 150 ° and 21
The circumferential movement amount Δ of the ball 29 at the phase of 0 ° is in the conventional case, that is, at the phases of φ = 120 ° and 240 ° when the ball 9 is assembled from φ = 0 ° as shown in FIG. Since the circumferential movement amount Δ ′ of the ball 9 is smaller, the width dimension of the column portion 34 between the pockets 33 of the cage 30 can be set large, and the strength of the cage 30 can be increased.

In the fixed type constant velocity universal joint according to the embodiment in which the maximum operating angle is further increased, the ratio of the cage offset amount f to the total offset amount (f + F) is (f + F) / PCR = 0. , F / (f + F) =
0.35 or more When (f + F) /PCR=0.2, f / (f + F) =
0.1 / or more, when (f + F) /PCR=0.3, f / (f + F) =
Since the setting is made so as to satisfy the condition of 0.03 or more, as shown in FIG. 3, the incorporation from φ = 30 ° or 330 ° is an advantageous range. On the other hand, in the conventional fixed type constant velocity universal joint, the cage offset amount f ′ and the total offset amount (f ′ +
F ′), when (f ′ + F ′) / PCR ′ = 0.14, f ′ /
(F ′ + F ′) = 0 (f ′ + F ′) / When PCR ′ = 0.15, f ′ / F ′
Since (f ′ + F ′) = 0.11 is set, the incorporation from φ = 0 ° is an advantageous range as shown in FIG.

The last ball 2 in the embodiment described above
The assembling procedure of No. 9 can be adopted for the assembling of the other balls 29 before inserting the last ball 29. If the assembling of all the balls 29 is performed in the manner described above, the cage radial direction can be changed. Since the ball 29 is not positioned 180 ° opposite to the ball insertion side, that is, at a phase of φ = 180 °, the axial length of the track is not required, and as a result, the axial length of the joint outer ring 25 can be reduced. As a result, the entire assembly can be made compact.

In the above embodiment, the case where the number of the balls 29 held by the cage 30 is six has been described. However, the present invention is not limited to this.
It is also applicable to the case where 9 is 8 pieces, and φ = ±
This is similar to the case where the range in which the incorporation from 22.5 ° becomes dominant is six. In that case, the load on one ball can be reduced and the efficiency can be increased, and the strength, the load torque, and the durability are excellent. The ball diameter can be reduced, and the entire joint can be reduced in size. It is.

Further, as shown in FIG. 1, a pocket gap t is formed so as not to restrain the ball 29 on the back side of the pocket 33 of the cage 30. In this way, even if the thickness of the cage 30 on the back side is reduced due to the increase in the cage offset amount f, the pockets 33 of the cage 30 are reduced.
By contacting the back side of the cage 30, damage to the back side of the cage 30 can be reduced, and the strength of the cage 30 can be secured.

[0036]

According to the first aspect of the present invention, the track offset amount F, the cage offset amount f, the line center connecting the center of curvature of the track groove of the outer ring of the joint or the center of curvature of the track groove of the inner ring of the joint and the center of the ball. When the length PCR is (f + F) /PCR=0.1, f / (f + F) =
0.35 or more When (f + F) /PCR=0.2, f / (f + F) =
0.1 / or more, when (f + F) /PCR=0.3, f / (f + F) =
By setting so as to satisfy the condition of 0.03 or more, it is possible to realize a higher maximum operating angle.

After achieving the maximum working angle,
According to the fourth aspect of the present invention, when the last ball is incorporated into the pocket of the cage, the ball is inserted from a direction forming a predetermined phase angle with respect to the cage radial direction passing through the center of the pocket. At this time, the circumferential movement amount of the ball on the track side having a curvature in the axial direction on the back side of the joint outer ring becomes smaller than in the conventional case, so the column width between the pockets can be set large. The strength of the cage can be easily increased.

Further, when the ball is assembled, the ball is not positioned 180 ° opposite to the ball insertion side in the cage radial direction, so that the axial length of the track is not required. As a result, the axial length of the joint outer ring is reduced. And the size of the entire assembly can be reduced.

According to the second and fifth aspects of the present invention, since the number of balls is eight, the load on one ball can be reduced and the efficiency can be increased, and the strength, load torque and durability are excellent. As a result, the ball diameter can be reduced, and the entire joint can be reduced in size.

According to the third and sixth aspects of the present invention, the pocket gap is formed so as not to restrain the ball at the back of the pocket of the cage. Even if the wall thickness on the back side is reduced, the strength of the cage can be ensured.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a fixed type constant velocity universal joint according to the present invention.

FIG. 2 is a sectional view showing a state in which the last ball is inserted into a pocket of a cage in the constant velocity universal joint of FIG. 1;

FIG. 3 is a characteristic diagram showing an effective range in which the last ball is incorporated in the constant velocity universal joint of FIG. 1;

FIG. 4 is a sectional view showing a conventional example of a fixed type constant velocity universal joint.

FIG. 5 is a cross-sectional view showing a state where the last ball is incorporated in the conventional constant velocity universal joint.

FIG. 6 is a cross-sectional view showing a state in which the last ball is inserted into a cage pocket in a conventional constant velocity universal joint.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 21 Inner spherical surface of joint outer ring 22 Track groove of joint outer ring 23 Open end 25 Joint outer ring 26 Outer spherical surface of joint inner ring 27 Track groove of joint inner ring 28 Joint inner ring 29 Ball 30 Cage 31 Inner spherical surface of cage 32 Outer spherical surface of cage 33 Pocket f Cage offset amount F Track offset amount O ₁ Center of curvature of track groove of joint outer ring O ₂ Center of curvature of track groove of joint inner ring O ₃ Center of inner spherical surface of cage O ₄ Center of outer spherical surface of cage t Pocket gap

Claims (6)

[Claims] 1. A joint outer ring having a plurality of track grooves formed on an inner spherical surface at equal intervals in a circumferential direction toward an open end along an axial direction, and a plurality of paired grooves formed on the outer spherical surface with the track grooves of the joint outer ring. A joint inner ring in which track grooves are formed at equal circumferential intervals along the axial direction, a plurality of balls interposed between the track grooves of the joint outer ring and the joint inner ring to transmit torque, and an inner spherical surface of the joint outer ring A fixed type constant velocity universal joint comprising a cage interposed between an outer spherical surface of a joint inner ring and a cage for holding a ball, wherein a center of curvature of a track groove of the outer ring of the joint, and a center of curvature of a track groove of the inner ring of the joint. Are offset axially equidistantly with respect to the joint center plane including the ball center, and the outer spherical surface center and the inner spherical surface center of the cage are axially offset with respect to the joint central surface. Offset opposite by equal distance Is, F the track offset amount of the former,
When the latter cage offset amount is f and the length of a line connecting the center of curvature of the track groove of the outer ring of the joint or the center of curvature of the track groove of the inner ring of the joint and the center of the ball is PCR, (f + F) / PCR = 0 , F / (f + F) =
0.35 or more When (f + F) /PCR=0.2, f / (f + F) =
0.1 / or more, when (f + F) /PCR=0.3, f / (f + F) =
A fixed type constant velocity universal joint characterized by being set so as to satisfy a condition of 0.03 or more. 2. The fixed type constant velocity universal joint according to claim 1, wherein the number of the balls is eight. 3. The fixed type constant velocity universal joint according to claim 1, wherein a pocket gap is formed so as not to restrain the ball on the back side of the pocket of the cage. 4. A joint outer ring having a plurality of track grooves formed on the inner spherical surface at equal intervals in the circumferential direction toward the open end along the axial direction, and a plurality of paired grooves formed on the outer spherical surface with the track grooves of the joint outer ring. A joint inner ring in which track grooves are formed at equal circumferential intervals along the axial direction, a plurality of balls interposed between the track grooves of the joint outer ring and the joint inner ring to transmit torque, and an inner spherical surface of the joint outer ring A method of assembling a fixed type constant velocity universal joint having a cage interposed between an outer spherical surface of a joint inner ring and a cage for holding a ball, wherein a center of curvature of a track groove of the joint outer ring and a track groove of the joint inner ring are provided. The center of curvature is offset by an equal distance in the axial direction from the joint center plane including the ball center, and the center of the outer spherical surface and the center of the inner spherical surface of the cage are relative to the joint center plane. Equal distance on the opposite side in the axial direction F is the former track offset amount, f is the latter cage offset amount, and P is the length of the line connecting the center of curvature of the track groove of the outer ring of the joint or the center of curvature of the track groove of the inner ring of the joint with the center of the ball.
When CR, (f + F) /PCR=0.1, f / (f + F) =
0.35 or more When (f + F) /PCR=0.2, f / (f + F) =
0.11 or more When (f + F) /PCR=0.3, f / (f + F) =
0.03 or more, and when inserting the last ball into the pocket of the cage, the ball is inserted from a direction forming a predetermined phase angle with respect to the cage radial direction passing through the center of the pocket. Method for assembling a fixed type constant velocity universal joint. 5. The method according to claim 4, wherein the number of the balls is eight. 6. The method for assembling a fixed type constant velocity universal joint according to claim 4, wherein a pocket gap is formed so as not to restrain the ball on the inner side of the pocket of the cage.