JPH10103365A - Constant velocity universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform compacting, and to ensure strength, load capacity, and durability. SOLUTION: Eight pieces of torque transmission balls 3 are arranged. A ratio R1 (=PCDball /Dball ) between a pitch circle diameter PCDball and a diameter Dball of the torque transmission ball 3 is set to a value within a range of 3.3<=r1<=5.0. A ratio r2 (=Douter /PCDserr ) between an outside diameter Douter of an outer wheel 1 and a pitch circular PCDserr of the serration (or a spline) 2c of an inner ring 2 is set to a value within a range of 2.5<=r2<=3.5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant velocity universal joint having eight torque transmitting balls.

[0002]

FIG. 15 shows a typical Zepper type constant velocity universal joint as a constant velocity universal joint. This constant velocity universal joint has an outer ring 11 as an outer joint member in which six curved guide grooves 11b are formed in an axial direction on a spherical inner surface 11a, and six curves on a spherical outer surface 12a. Serrated (or spline) 12 for forming a shaft-shaped guide groove 12b in the axial direction and connecting the shaft to the inner diameter surface.
c, an inner ring 12 as an inner joint member, and an outer ring 1
Six torque transmission balls 13 disposed on six ball tracks formed by the one guide groove 11b and the guide groove 12b of the inner race 12 in cooperation with each other;
And a holder 14 for holding the

The center A of the guide groove 11b of the outer ring 11 is relative to the center of the spherical surface of the inner surface 11a, and the center B of the guide groove 12b of the inner ring 12 is relative to the center of the spherical surface of the outer surface 12a.
On the opposite side by the same distance in the axial direction (center A is the opening side of the joint,
The center B is offset (to the far side of the joint). Therefore, the ball track formed by the cooperation of the guide groove 11b and the corresponding guide groove 12b has a wedge-like shape toward the opening side of the joint. The spherical centers of the inner diameter surface 11a of the outer ring 11 and the outer diameter surface 12a of the inner ring 12, which are guide surfaces of the retainer 14, are all within the joint center plane O including the center of the torque transmission ball 13.

When the outer race 11 and the inner race 12 are angularly displaced by an angle θ, the torque transmitting ball 1 guided by the cage 14
3 is always maintained within the bisecting plane (θ / 2) of the angle θ at any operating angle θ, so that the constant velocity of the joint is ensured.

According to the present invention, the constant velocity universal joint as described above is further compacted, and has a strength and load equal to or greater than that of a comparative product (the six-ball constant velocity universal joint as described above). The purpose is to secure capacity and durability.

[0006]

In order to solve the above problems, the present invention sets the number of ball tracks and the number of arranged torque transmitting balls to eight.

Further, a ratio r1 (= PCD) between the pitch circle diameter (PCD _BALL ) and the diameter (D _BALL ) of the torque transmitting ball is obtained.
_BALL / D _BALL ) was set to 3.3 ≦ r1 ≦ 5.0.

Here, the pitch circle diameter (PCD _BALL ) of the torque transmitting ball is defined by the center of the guide groove of the outer joint member (outer ring) or the center of the guide groove of the inner joint member (inner ring) and the center of the torque transmitting ball. The length of the line connecting the center of the guide groove of the outer joint member (outer ring) and the center of the torque transmitting ball, the center of the guide groove of the inner joint member (inner ring) and the center of the torque transmitting ball. Is equal to the length of the line segment connecting. Thereby, the constant velocity of the joint is ensured. Hereinafter, this dimension is referred to as (PCR). ｝ Twice (PCD _BALL = 2
× PCR).

The reason for setting 3.3 ≦ r1 ≦ 5.0 is that the strength of the outer ring, the load capacity of the joint and the durability are comparative products (FIG. 1).
This is to ensure that it is equal to or greater than that of a six-ball constant velocity universal joint as shown in FIG. That is, in the constant velocity universal joint, it is difficult to largely change the pitch circle diameter (PCD _BALL ) of the torque transmission ball within a limited space. Therefore, the value of r1 mainly depends on the diameter (D _BALL ) of the torque transmitting ball. r1 <3.3
In the case of (mainly when the diameter D _BALL is large), the thickness of other parts (outer ring, inner ring, etc.) becomes too thin, and there is a concern in terms of strength. Conversely, if r1> 5.0 (mainly when the diameter _DBALL is small), the load capacity becomes small, and there is a concern about durability. Also, the surface pressure at the contact portion between the torque transmitting ball and the guide groove increases (because the smaller the diameter D _BALL , the smaller the contact ellipse at the contact portion). It is feared that it will become.

By setting 3.3 ≦ r1 ≦ 5.0,
The strength of the outer ring and the like, the load capacity of the joint, and the durability can be ensured to be equal to or more than those of the comparative product (six balls). This has been confirmed to some extent by tests.

[0011]

[Table 1]

As shown in Table 1 (Table 1 shows the evaluation based on the comparative test), when r1 = 3.2, the strength of the outer ring, the inner ring, and the retainer is not sufficiently secured, and Undesirable results were obtained. In the case of r1 = 3.3, 3.4, good results were obtained in terms of strength. In particular, when r1 ≧ 3.5, the outer ring, the inner ring,
The strength of the cage and the durability of the joint were sufficiently ensured, and favorable results were obtained. Although the test has not been carried out for the range of r1> 3.9, it is presumed that preferable results are obtained in the same manner as described above. Where r
1> 5.0, it is considered that durability and the strength of the inner and outer rings are considered to be problems as described above.
It is better to set ≦ 5.0.

As described above, r1 is 3.3 ≦ r1 ≦ 5.
It is good to set in the range of 0, preferably in the range of 3.5 ≦ r1 ≦ 5.0.

Further, in the present invention, the ratio r1 between the pitch circle diameter (PCD _BALL ) and the diameter (D _BALL ) of the torque transmitting ball is provided.
(= PCD _BALL / D _BALL ) is set to 3.3 ≦ r1 ≦ 5.0, and the outer diameter (D _OUTER ) of the outer joint member and the tooth shape of the inner joint member (teeth for connecting the shaft portion) Mold (formed on the inner diameter surface of the inner joint member).
_SERR ) and the ratio r2 (= D _OUTER / PCD _SERR ) to 2.5
≦ r2 ≦ 3.5.

The reason for setting 3.3 ≦ r1 ≦ 5.0 is the same as above. As a preferred range, 3.5 ≦ r1
The same holds true for ≦ 5.0. 2.5 ≦ r2 ≦ 3.
The reason for setting 5 is as follows. That is, the pitch circle diameter (PCD _SERR ) of the tooth form of the inner joint member cannot be largely changed in relation to the strength of the mating shaft and the like. Therefore, r2
_Will mainly depend on the outer diameter (D _OUTER ) of the outer joint member. If r2 <2.5 (mainly the outer diameter D
_{When OUTER} is small), the thickness of each component (outer ring, inner ring, etc.) becomes too thin, and there is concern about strength. On the other hand, r
If 2> 3.5 (mainly when the outer diameter D _OUTER is large), a practical problem arises in terms of dimensions and the like. 2.
By setting 5 ≦ r2 ≦ 3.5, the strength of the outer ring and the like and the durability of the joint can be ensured to be equal to or higher than that of the comparative product (six balls), and the practical demand can be satisfied.
Particularly, by setting 2.5 ≦ r2 <3.2, there is an advantage that the outer diameter can be made smaller than a comparative product of the same nominal type (six balls: generally r2 ≧ 3.2). There is.

As described above, r2 is 2.5 ≦ r2 ≦ 3.
5 is set, preferably in the range of 2.5 ≦ r2 <3.2.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the constant velocity universal joint according to this embodiment has an outer race 1 as an outer joint member having eight curved guide grooves 1b formed in the axial direction on a spherical inner surface 1a.
And an inner joint member in which eight curved guide grooves 2b are formed in the spherical outer diameter surface 2a in the axial direction and serrations (or splines) 2c for connecting the shaft portion 5 to the inner diameter surface are formed. An inner ring 2 and eight torque transmitting balls 3 respectively arranged on eight ball tracks formed in cooperation with a guide groove 1b of the outer ring 1 and a corresponding guide groove 2b of the inner ring 2. And a retainer 4 for retaining the torque transmitting ball 3.

In this embodiment, the guide groove 1 of the outer race 1
the center O1 of the inner ring 2 with respect to the center of the spherical surface of the inner surface 1a.
The center O2 of the guide groove 2b is opposite to the center of the spherical surface of the outer diameter surface 2a by an equal distance (F) in the axial direction (the center O1 is the opening side of the joint, and the center O2 is the back side of the joint). To) offset. Therefore, the ball track formed by the cooperation of the guide groove 1b and the corresponding guide groove 2b has a wedge-shaped shape toward the opening side of the joint.

The center of the spherical surface of the outer diameter surface 4a of the retainer 4 and the center of the spherical surface of the inner diameter surface 1a of the outer ring 1 serving as a guide surface of the outer diameter surface 4a of the cage 4 are both the center of the torque transmitting ball 3. It is in the joint center plane O including O3. In addition, cage 4
Center of the spherical surface of the inner diameter surface 4b and the inner diameter surface 4 of the cage 4
The center of the spherical surface of the outer diameter surface 2a of the inner ring 2 serving as the guide surface of b is in the joint center plane O. Therefore, the offset amount (F) of the outer ring 1 is the axial distance between the center O1 of the guide groove 1b and the joint center plane O, and the offset amount (F) of the inner ring 2 is the center O2 of the guide groove 2b. And the joint center plane O, which are equal. Guide groove 1 of outer ring 1
The center O1 of the guide groove 1b and the center O2 of the guide groove 2b of the inner ring 2 are opposite to each other by an equal distance (F) in the axial direction with respect to the joint center plane O (the center O1 of the guide groove 1b is the opening side of the joint, the guide groove The center O2 of 2b is located at a position shifted toward the inner side of the joint). Outer ring 1
Center O1 of the guide groove 1b and center O of the torque transmitting ball 3
The length of the line segment connecting the center O3 of the inner ring 2 and the length of the line segment connecting the center O2 of the guide groove 2b of the inner ring 2 and the center O3 of the torque transmitting ball 3 is PCR, and both are equal.

When the outer race 1 and the inner race 2 are angularly displaced by the angle θ, the torque transmitting ball 3 guided by the retainer 4 always divides the angle θ into two equal planes (θ / 2) at any operating angle θ.
And the constant velocity of the joint is ensured.

As described above, the pitch circle diameter PCD _BALL (PCD
Ratio r1 (= PCD) between _BALL = 2 × PCR) and diameter D _BALL
(BALL / D _BALL ) is set to a value in the range of 3.3 ≦ r1 ≦ 5.0, preferably in a range of 3.5 ≦ r1 ≦ 5.0, to secure the strength of the outer ring and the like and to maintain the load capacity. However, in this embodiment, r1 = 3.
83 is set. The ratio r2 between the outer diameter D _OUTER of the outer ring 1 and the pitch circle diameter PCD _SERR of the serration (or spline) 2c of the inner ring 2
(= D _OUTER / PCD _SERR ) 2.5 ≦ r2 ≦ 3.5,
For example, it is set to a value within the range of 2.5 ≦ r2 <3.2. Note that the above configuration may be employed alone.

Table 2 shows a comparison of the above structure with a comparative product having the same nominal type (a constant velocity universal joint having six balls as shown in FIG. 15).

[0024]

[Table 2]

In the constant velocity universal joint of this embodiment, the number of the torque transmitting balls 3 is eight, and the comparative product (six balls) is used.
Torque transmission ball 1 in the total load capacity of the joint
Since the load ratio per piece is small, the diameter D of the torque transmitting ball 3 is compared with the comparative product (six balls) of the same nominal type.
_{It is possible to make the BALL} small, and to secure the thickness of the outer ring 1 and the thickness of the inner ring 2 at the same level as the comparative product (six balls).

The ratio r2 (= D _OUTER / PCD _SERR ) is reduced (2.5 ≦ r2 <3.2) with respect to the comparative product (six balls) having the same nominal type, and the comparative product (six balls) is used. Ball), while maintaining strength, load capacity and durability equal to or higher than that of the ball), and further downsizing can be achieved.

FIG. 2 shows the outer race 1. A cylindrical cut portion 1a1 for incorporating the retainer 4 into the inner diameter surface 1a is provided in the opening side region of the inner diameter surface 1a of the outer ring 1. When assembling the retainer 4, as shown in FIG.
With the axes perpendicular to each other, the pocket 4
c is put into the cylindrical cut portion 1a1. In this manner, the retainer 4 is arranged such that the center of the spherical surface of the outer diameter surface 4 a is the inner diameter surface 1 of the outer ring 1.
Insert until it matches the spherical center of a. From this state,
The retainer 4 is rotated by 90 degrees so that the axis of the retainer 4 and the axis of the outer ring 1 match. Thereby, the retainer 4 is completely assembled on the inner diameter surface 1a of the outer race 1.

As shown in FIGS. 2C and 2D, a chamfer 1b1 is provided in a region of the outer race 1 on the opening side of the guide groove 1b. When heat-treating the guide groove 1b, the chamfer 1b1 heat-treats the region W in FIG. 2D.役 割 has the role of preventing burn-through (outer ring 1
Of the torque transmitting ball 3 can be used as a guide when the torque transmitting ball 3 is incorporated into the pocket 4c of the retainer 4.

FIG. 3 shows the inner race 2. The diameter of the outer diameter surface 2a of the inner ring 2 is A, and the two guide grooves 1 facing each other by 180 degrees.
The maximum distance between the outer diameter surfaces 2a in a vertical section parallel to the plane S including the groove bottom b is C.

FIG. 4 shows the retainer 4. Cage 4
Are provided with eight window-shaped pockets 4c for accommodating and holding the torque transmitting ball 3 at equal circumferential intervals. Four of the eight pockets 4c are long pockets 4c1 having a large circumferential dimension, and the remaining four are short pockets 4 having a small circumferential dimension.
At c2, the long pockets 4c1 and the short pockets 4c2 are alternately arranged. The diameter (B) of the inlet 4d of the retainer 4 in which the inner ring 2 is incorporated is determined by the relationship of C ≦ B <A with respect to the outer diameter (A) of the inner ring 2 shown in FIG. It is set to be. A step 4e is formed on the inner side of the entrance 4d (the boundary between the inner diameter surface 4b and the entrance 4d).

The reason why the diameter (B) of the inlet portion 4d is set so as to satisfy the relationship of C ≦ B <A is to take into consideration the ease of assembling the inner ring 2 into the inner diameter surface 4b of the retainer 4. When assembling the inner ring 2, one guide groove 2 b of the inner ring 2 is inserted into the entrance 4 d of the retainer 4 in a state where the axes are orthogonal to each other.
, The inner ring 2 is inserted into the inner surface 4 b of the retainer 4. When the inner race 2 is inserted to some extent in this manner, the maximum interval (C) between the outer diameter surfaces 2a of the inner race 2 is caught by the step 4e, and the inner race 2 cannot be inserted any more (the state shown in FIG. 5). From this state, the inner ring 2 is rotated by 90 degrees, and the axis of the inner ring 2 and the axis of the retainer 4 are aligned. Thereby, the inner race 2 is completely assembled on the inner diameter surface 4b of the retainer 4.

The reason why the four long pockets 4c1 and the four short pockets 4c2 are alternately arranged is that the torque transmitting ball 3
This is because consideration has been given to the ease of assembling when the device is assembled into the pocket 4c of the retainer 4. As shown in FIG. 6 (a), the assembly of the torque transmission ball 3 is performed by assembling the assembly of the inner ring 2 and the retainer 4 on the inner surface 1 a of the outer ring 1, and then connecting the inner ring 2 and the retainer 4 to the outer ring 1. This is performed in a state of being angularly displaced (the ball assembling angle α). The torque transmitting balls 3 in each phase of FIG. 6B are indicated by 31, 32,... The torque transmitting balls 31, 33, 35 and 37 are accommodated in the short pockets 4 c 2 of the retainer 4, and the torque transmitting balls 3
2, 34, 36 and 38 are accommodated in the long pocket 4c1. The movement position of the torque transmitting ball 3 in the pocket 4c when the joint has the operating angle α is as shown in FIG. 7A corresponds to the configuration of FIG. 1 without the cage offset (f), and FIG. 7B corresponds to the configurations of FIGS. 11 and 12 with the cage offset (f). I have. First, the torque transmitting balls 3 are assembled into the four long pockets 4c1, respectively, and then assembled into the four short pockets 4c2. For example, torque transmitting ball 3
When 1 is incorporated, the amount of movement of the torque transmitting ball 3 in the circumferential direction is small in the phases of 33, 35, and 37. Therefore, the torque transmission ball 31 can be incorporated in the short pocket 4c2. Similarly, for example, when the torque transmitting ball 33 is assembled, in the phases of 31, 35, and 37, the torque transmitting ball 3
Has a small amount of movement in the circumferential direction. Therefore, the torque transmission ball 33 can be incorporated in the short pocket 4c2. Thus, the torque transmitting balls 3 can be incorporated in all the short pockets 4c2. When the torque transmitting ball 3 is incorporated into the pocket 4c, the chamfer 1b1 of the outer race 1 plays a role of guiding the torque transmitting ball 3 (FIG. 6A).
reference}.

When the outer ring 1, the inner ring 2, the retainer 4, and the torque transmitting ball 3 are assembled in the above-described manner, the constant velocity universal joint of the present embodiment shown in FIG. 1 is completed. The shaft portion 5 is connected to the serration (or spline) 2c of the inner race 2. In this embodiment, the shaft portion 5 is formed of boron steel to reduce the diameter of the shaft portion 5 (when the maximum operating angle is given,
The diameter of the portion that interferes with the open end of the outer ring 1 is reduced.
The serration diameter is the same as the comparative product. ). The reason why the diameter of the shaft portion 5 is reduced is that consideration is given to an increase in the operating angle. In the prototype, for example, a maximum operating angle of 45 ° or more required for a joint for a drive shaft of an automobile could be sufficiently achieved.

FIG. 8 shows the embodiment product and the comparative product (six-ball constant velocity universal joint) (all having the same nominal type).
3 shows the results of a comparative test of the relationship between the rotation speed (rpm) and the amount of temperature rise (° C.). In this figure, X (dotted white circle) is the product of the embodiment, Y (solid black circle) is the comparative product, and the temperature rise (° C) is data measured 30 minutes after the start of operation. Θ is the joint operating angle, and T is the input rotational torque.

As is clear from the test results shown in FIG.
The temperature rise of the embodiment product (X) is smaller than that of the comparative product (Y), and the difference increases as the rotation speed increases. Reducing the temperature rise leads to improved durability. Further, it is considered that such a reduction in temperature rise can be obtained regardless of the operating angle (θ) and the input rotation torque (T).

FIG. 9 shows the results of a comparative test of the change over time in the temperature rise (° C.) for the embodiment product and the comparative product (six balls) (all having the same nominal type).
In the figure, X (dotted white circle) is the embodiment product, Y (solid line black circle) is the comparative product, θ is the joint operating angle, and T is the input rotation torque.

As is clear from the test results shown in FIG.
The temperature rise amount of the embodiment product (X) is smaller than that of the comparative product (Y), and the difference does not change much even when the operation time becomes longer.

FIG. 10 shows the working angle θ (d) of the embodiment product and the comparative product (six balls) (all having the same nominal type).
3 shows the results of a comparative test of the relationship between the torque loss rate (eg) and the torque loss rate (%). In the figure, X (dotted white circle) indicates the product of the embodiment
Y (solid black circle) is a comparative product, and the input rotation torque T = 196 N · m at θ = 10 deg and T at θ = 30 deg.
= 98 N · m, and the torque loss rate is measured.

As can be seen from the figure, the torque loss rate of the embodiment product (X) is smaller than that of the comparative product (Y), and the difference increases as the operating angle θ increases. Reduction of torque loss contributes to fuel saving and energy saving, and also leads to reduction of temperature rise and improvement of durability.

Table 3 shows the results of observations of the outer ring, inner ring, cage, and balls after 300 hours of operation for the embodiment product and the comparative product (six balls) (all having the same nominal type). I have. For the cage, the wear depth of the pocket portion was measured, and the result is shown in FIG. The test conditions were as follows: θ = 6 deg, T = 1078 N · m, rotation speed = 200 rpm, total rotation speed = 3.60 × 10 6 (re
v). Note that the test is performed using two test products each as the embodiment product and the comparison product (the embodiment product is NO
1 and 2, the comparative products are NO3 and 4), and the wear depth shown in FIG. 11 is an average value of the two test products.

[0041]

[Table 3]

As is evident from the results shown in Table 3, no damage was found in each part of the embodiment product and the comparative product. Further, as is clear from the results shown in FIG. 11, the wear depth of the pocket portion of the cage in the embodiment product (X) was smaller than that of the comparative product (Y).

As described above, according to the constant velocity universal joint of this embodiment, it is possible to provide a load capacity and durability equal to or higher than that of the comparative product (six balls) while having a compact shape. .

FIG. 12 shows a constant velocity universal joint according to another embodiment of the present invention. The center O1 of the guide groove 1b of the outer ring 1 is axially equidistant from the spherical center O4 of the inner diameter surface 1a, and the center O2 of the guide groove 2b of the inner ring 2 is equal to the spherical center O5 of the outer diameter surface 2a. (F) is offset to the opposite side. Furthermore, in this embodiment, the spherical center of the outer diameter surface 4a of the retainer 4 (the same as the spherical center O4 of the inner diameter surface 1a of the outer ring 1) and the spherical center of the inner diameter surface 4b of the retainer 4 (the outer diameter of the inner ring 2) (Same as the spherical center O5 of the surface 2a) with respect to the joint center plane O in the axial direction on the opposite side by the same distance (f). The offset amount (F) of the outer ring 1 is the axial distance between the center O1 of the guide groove 1b and the center O4 of the inner diameter surface, and the offset amount (F) of the inner ring 2
Is the center O2 of the guide groove 2b and the spherical center O5 of the outer diameter surface 2a.
And the two are equal. The center O1 of the guide groove 1b of the outer ring 1 and the center O2 of the guide groove 2b of the inner ring 2 are on the opposite side by an equal distance in the axial direction with respect to the joint center plane O (the center O1 of the guide groove 1b is the opening side of the joint, The center O2 of the guide groove 2b is located at a position shifted toward the inner side of the joint). Outer ring 1
Center O1 of the guide groove 1b and center O of the torque transmitting ball 3
The length of the line segment connecting the center O3 of the inner ring 2 and the length of the line segment connecting the center O2 of the guide groove 2b of the inner ring 2 and the center O3 of the torque transmitting ball 3 is PCR, and both are equal. Since the configuration in the above embodiment is the same, the description is omitted.

In the embodiment shown in FIG. 13, a predetermined area U1 of the guide groove 1b of the outer ring 1 and a predetermined area U of the guide groove 2b of the inner ring 2 are shown.
2 is a straight shape. Guide groove 1
The area b other than U1 has a curved shape centered on the point O1, and the area other than U2 of the guide groove 2b has a curved shape centered on the point O2. Other configurations are the same as those of the above-described embodiment, and thus the description will be omitted.

In this type of constant velocity universal joint, the positional relationship between the center of the outer ring guide groove, the center of the inner ring guide groove, the spherical center of the inner ring inner diameter surface, and the spherical center of the inner ring outer diameter surface is as shown in FIG. Eight variations {Figs. 14 (a) to 14]
(H) Although there is｝, the present invention can be applied to any of the configurations. By the way, the configuration of FIG.
The configurations of FIG. 12B and FIGS. 12 and 13 correspond to FIG. 14A, respectively.

The present invention is not limited to a constant velocity universal joint having a configuration in which the inner ring and the shaft are connected by a tooth form (serration or spline), but a constant velocity universal joint having a configuration in which the inner ring and the shaft are integrated. Is also applicable. For example, after the inner ring, the retainer, and the ball are assembled into the outer ring, the shaft may be integrally joined to the end surface of the inner ring (welding, for example, laser beam welding, pressure welding, or the like).

Further, the constant velocity universal joint of the present invention
It can be widely used as a power transmission element in various industrial machines and the like.

[0049]

As described above, according to the present invention,
It is possible to further reduce the size of the constant velocity universal joint, and at the same time, it is possible to secure strength, load capacity, and durability equal to or more than those of the comparative product (six balls).

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention (FIG. A: FIG. B)
2 is a sectional view taken along a line a-a in FIG. 2, and a cross-sectional view is shown in FIG.

FIG. 2 is a front view of the outer race (FIG. A), a vertical sectional view (FIG. B), an enlarged front view of a guide groove portion in FIG.
It is an expanded longitudinal cross-sectional view (FIG. D) of the end part in FIG. B.

FIG. 3 is a front view (FIG. A) and a longitudinal sectional view (FIG. B) of the inner race.

FIG. 4 is a cross-sectional view (FIG. A) and a vertical cross-sectional view (FIG. B) of the cage.
It is.

FIG. 5 is a front view showing an embodiment when the inner ring is assembled into the retainer.

FIG. 6 is a longitudinal sectional view (FIG. A) and a transverse sectional view (FIG. B) showing an aspect when a torque transmitting ball is incorporated.

FIG. 7 is a diagram showing a moving position of a torque transmitting ball in a pocket at an operating angle α. FIG. 7A corresponds to a configuration without a cage offset, and FIG. 6B corresponds to a configuration with a cage offset.

FIG. 8 is a diagram showing the relationship between the number of rotations and the amount of temperature rise (FIGS. A, b, and c).

FIG. 9 is a diagram showing a change over time in the amount of temperature rise.

FIG. 10 is a diagram showing a relationship between an operating angle and a torque loss rate.

FIG. 11 is a view showing a result of measuring a wear depth of a pocket portion of the cage.

FIG. 12 is a longitudinal sectional view (FIG. A: a-a section in FIG. B) and a transverse sectional view (FIG. B: FIG. A) showing another embodiment of the present invention.
Bb section).

FIG. 13 is a longitudinal sectional view (FIG. A: a-a section in FIG. B) and a transverse sectional view (FIG. B: FIG. A) showing another embodiment of the present invention.
Bb section).

FIG. 14 shows the center of the outer ring guide groove in the constant velocity universal joint,
It is a figure which shows the variation of the positional relationship of the center of an inner ring guide groove, the center of an outer ring inner diameter surface (retainer outer diameter surface), and the center of an inner ring outer diameter surface (retainer inner diameter surface).

FIG. 15 is a cross-sectional view (FIG. A) and a vertical cross-sectional view (FIG. B: b- in FIG. A) showing a comparative product (constant velocity universal joint of six balls).
(b sectional view).

[Explanation of symbols]

 Reference Signs List 1 outer ring 1a inner diameter surface 1b guide groove 2 inner ring 2a outer diameter surface 2b guide groove 3 torque transmitting ball 4 cage

Claims (3)

[Claims] 1. An outer joint member having a plurality of axially extending guide grooves formed in a spherical inner diameter surface, an inner joint member having a plurality of axially extending guide grooves formed in a spherical outer diameter surface,
A torque transmitting ball disposed on each of a plurality of ball tracks formed by the guide groove of the outer joint member and the corresponding guide groove of the inner joint member cooperating with each other, and a retainer holding the torque transmitting ball. A constant velocity universal joint, wherein the number of the ball tracks and the number of torque transmitting balls are eight, wherein the number of the ball tracks and the number of the torque transmitting balls are eight. 2. A pitch circle diameter (P) of the torque transmitting ball.
Ratio r1 (= PCD _BALL ) between CD _BALL ) and diameter (D _BALL )
The constant velocity universal joint according to claim 1, wherein / D _{BALL satisfies} 3.3 ≦ r1 ≦ 5.0. 3. A pitch circle diameter (P) of the torque transmitting ball.
Ratio r1 (= PCD _BALL ) between CD _BALL ) and diameter (D _BALL )
/ D _BALL ) satisfies 3.3 ≦ r1 ≦ 5.0, and connects an outer diameter (D _OUTER ) of the outer joint member to a shaft portion formed on an inner diameter surface of the inner joint member. Ratio r2 (= D _OUTER / PC) to the pitch circle diameter (PCD _SERR ) of the tooth form
2. The constant velocity universal joint according to claim 1, wherein D _{SERR satisfies} 2.5 ≦ r2 ≦ 3.5.