JP3480140B2 - Universal joint - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The universal joint according to the present invention is incorporated in, for example, a steering device of an automobile and is used for transmitting the movement of a handle shaft to a steering gear.

[0002]

2. Description of the Related Art A cross joint called a cardan joint has been widely known as a universal joint used for a steering device of an automobile. For example, Actual Kaihei 5-3652
The publication describes a universal joint as shown in FIG. 11 which is incorporated in a steering device as shown in FIG. As shown in FIG. 10, the steering device is configured so that the movement of the steering wheel 1 is transmitted to a steering gear 4 via a steering shaft 2 and an intermediate shaft 3, and the steering gear 4 steers the wheels. The steering shaft 2 and steering gear 4
Normally, the input shaft 5 and the input shaft 5 are not provided on the same straight line. Therefore, the intermediate shaft 3 is provided between the both shafts 2 and 5, and both ends of the intermediate shaft 3 and the ends of the steering shaft 2 and the input shaft 5 are connected to the universal joints 6 and 6 which are objects of the present invention. Are connected through.

Regarding the structure of each of these universal joints 6, 6,
12 will be described in addition to FIG. 11 described above. The structure shown in FIG. 11 is a so-called vibration-proof joint that prevents transmission of vibration, but the universal joint that is the subject of the present invention does not necessarily have to have a vibration-proof structure. Therefore, in the following description, the vibration proof structure will be omitted and the universal joint 6 will be described. The universal joint 6 is composed of a pair of yokes 7a and 7b each formed in a bifurcated shape with a metal material having sufficient rigidity, and a cross shaft 8 made of a hard metal such as alloy steel. . Circular holes 9, 9 concentric with each other are formed at both ends of each of the yokes 7a, 7b. And each circular hole 9, 9
Further, the bearing cups 10 and 10, which are also made of a hard metal such as bearing steel and have a bottomed cylindrical shape, are internally fitted and fixed with their openings facing each other. The cross shaft 8 has a shape in which the intermediate portions of a pair of pillars are orthogonal to each other,
It has four shaft portions 11, 11 each having a cylindrical shape. The four shaft parts 11, 11 are inserted into the bearing cups 10, 10. A radial bearing 12, such as a needle bearing, is provided between the inner peripheral surface of each of the bearing cups 10 and 10 and the outer peripheral surface of each of the shaft portions 11 and 11.
12 is provided, and each of the yokes 7a is provided with respect to the cross shaft 8.
7b swings with a light force. With this configuration, even if the central axes of the two yokes 7a and 7b do not coincide with each other, the rotational force can be transmitted between the two yokes 7a and 7b with almost no transmission loss.

The basic structure of the universal joint 6 is as described above, but in such a universal joint 6, the space between the base portion 13 of the cross shaft 8 and the openings of the bearing cups 10 and 10 is provided. , And seal rings 14 and 14 are provided, respectively. The seal rings 14 and 14 prevent muddy water and the like from entering the installation portions of the radial bearings 12 and 12, thereby ensuring the durability of the universal joint 6.
Further, bottomed insertion holes 15 and 15 are provided in the central portions of the four shaft portions 11 and 11 , respectively.
Is formed in the axial direction of each of these shaft portions 11, 11 in a state of opening at the end face of the. Then, each of the above insertion holes 1
As described in detail in Japanese Utility Model Publication No. Sho 64-2982, pins 1 made of a synthetic resin are provided on the inside of Nos. 5 and 15.
6 and 16 are inserted.

Conventionally, each of these pins 16 and 16 has been formed in a shape as shown in FIG. 13 or 14. That is, the flange-shaped large-diameter portion 1 is provided at both axial ends of the cylindrical small-diameter portion 17.
8 and 18 are formed, and the outer end surfaces of the large-diameter portions 18 and 18 are frustoconical projection surfaces 19 and 19, respectively. The example shown in FIG. 13 is one in which ribs 20, 20 are formed from both axial ends of the small-diameter portion 17 to the base end portions of the large-diameter portions 18, 18, and the example shown in FIG. Such ribs 20, 2
0 is omitted. In any case, at the time of assembling the universal joint 6, the pins 16 and 16 are inserted into the insertion holes 1
5 and 15, one end of each of these insertion holes 15, 1
5 is abutted against the rear end of the bearing cup 5 and the other end is the bearing cup 1
It is struck against the bottom of 0 and 10.

The pins 16 and 16 are stretched between the bearing cups 10 and 10 and the shaft portions 11 and 11 to open the end portions of the bearing cups 10 and 10 and the base portion 13. Prevents the distance between and from becoming too short.
This is to prevent the respective seal rings 14, 14 from being excessively compressed, or conversely, the amount of compression being too low. That is, when the universal joint 6 is used, a thrust load is applied between the cross shaft 8 and the bearing cups 10 and 10. Therefore, if no measures are taken, the seal ring 14 on the thrust load acting side (anchor side) is excessively compressed and the durability is impaired, and the compression amount of the seal ring 14 on the opposite side (anti-anchor side) decreases. This seal ring 14
This is because the sealing property is impaired. Each pin 1
By supporting such a thrust load, the reference numerals 6 and 16 serve to keep the compression amounts of the seal rings 14 and 14 in an appropriate range.

Each of the pins 16 and 1 that fulfills such a role
In order to carry out the mounting work of 6, the pins 16 and
16, the insertion holes 15 existing at the positions opposite to each other in the axial direction,
Insert into 15. At this time, when the pin 16 shown in FIG. 13 is used, the pins 16 and 16 are inserted into the insertion holes 1 while the outer peripheral edge portions of the ribs 20 and 20 are plastically deformed.
The insertion holes 15 and 15 are press-fitted into the insertion holes 5 and 15 to the deep ends. After press-fitting, these pins 16 and 16 do not accidentally fall out of the insertion holes 15 and 15. Ribs 20,
When using the pin 16 shown in FIG. 14, which does not have the pin 20, after inserting the pins 16 and 16 into the insertion holes 15 and 15, until the bearing cups 10 and 10 are mounted as described below. between, in order to prevent falling off of the pins 16, 16, kept with suppressing the respective pins 16, 16.

In this way, with the pins 16 and 16 inserted into the insertion holes 15 and 15, the shaft portions 11 and 11 are inserted.
Is placed in the circular holes 9, 9 of the yoke 7a (7b). Then, the respective bearing cup 10, 10 in these circular holes 9, 9, and pressed from the outer end opening side, further toward the respective bearing cups 10, 10 to the respective shaft portions 11, 11, in a direction closer to each other Press. Of course, the base end portion of the shaft portions 11, 11 prior to the press work, previously fitted with the sealing ring 14, 14. Also, during the pressing operation, the radial bearings 12, 12 are set inside the bearing cups 10, 10. Furthermore, the open end of the bearing cups 10, 10 is previously squeezed in advance diametrically inwardly.

By the pressing work, the bearing cups 10 and 10 on the opposite side in the axial direction are internally fitted and fixed in predetermined positions in the circular holes 9 and 9 and the pins 16 and 16 are compressed in the axial direction. To be done. That is, these small-diameter portion 17 of each pin 16, 16, by being strongly clamped between the inner surface of the bottom and the respective insertion holes 15, 15 of the respective bearing cups 10, 10, 12 As shown, it transforms into a barrel. In this state, the pins 16 and 16 are connected to the bearing cups 10 and 10, respectively.
Between the bottom surface of the bearing cup 1 and the inner surface of each of the insertion holes 15 and 15 so as to support the bearing cup 1 regardless of the thrust load.
Prevents 0 and 10 from being displaced in the axial direction. As a result,
The amount of compression of each of the seal rings 14, 14 is properly maintained.

[0010] Incidentally, conventionally a synthetic resin forming the respective pin 16, 16, were using polyacetal resin. When a compressive load is applied to the pins 16 made of polyacetal resin, the relationship between the compressive load and the compressive amount is
As shown by the chain line a in FIG. 15, it becomes smooth. In other words, a slight difference in compression load does not significantly affect the compression amount. Therefore, there is no great difference in the amount of compression of the pair of pins 16 and 16 existing at the axially opposite positions due to the pressing work. That is, these pins 16, 16
The compression characteristics of may differ somewhat due to errors that cannot be avoided in manufacturing (dimension errors, material quality errors). If the relationship between the compression load and the compression amount is smooth as shown by the chain line a, there is no great difference between the compression amounts of the pair of pins 16 and 16, and the pins 1 and 2 exist at the opposite positions in the axial direction. There is no significant difference in the amount of compression between the pair of seal rings 14, 14.

[0011]

However, in the case of the conventional universal joint constructed and operated as described above, the pin 1 is used.
Due to the material of the synthetic resin constituting 6, 16, there are the following points to be solved. That is, these pins 16,
While the polyacetal resin conventionally used as the synthetic resin forming 16 is not necessarily sufficient in heat resistance, the universal joint 6 forming the steering device is provided in a high temperature engine room. In particular, there is a tendency that the temperature in the engine room becomes higher due to the improvement of the engine output in recent years or the reduction of the space in the engine room due to the increase of auxiliary machines. Moreover, since the universal joint for the steering device is often arranged adjacent to the exhaust pipe, it must be taken into consideration that it is exposed to a considerably high temperature. In the case of the polyacetal resin pins 16 and 16, when they are exposed to a high temperature, they are softened and deformed.
There may be a gap between the end of 6 and the bottom surface of the bearing cup 10, 10. And if there is a gap,
Rattling is generated at the universal joint 6 portion, which gives an uncomfortable feeling to the driver who operates the steering wheel 1 (FIG. 10).
An unfavorable phenomenon occurs.

If a heat-resistant synthetic resin is used as the synthetic resin forming the pins 16 and 16, the above-mentioned problems can be solved, but instead, due to the characteristics of the heat-resistant synthetic resin, The problem as described in 1. occurs. That is, when a compressive load is applied to a general heat-resistant synthetic resin pin, the relationship between the compressive load and the compressive amount is as shown by the broken line b in FIG. As is clear from the broken line b, the yield point clearly appears as a material characteristic of a general heat resistant synthetic resin. As a result, when the compression load and the compression amount exceed a certain value, the compression amount suddenly becomes large (large) despite the change amount of the compression load being small (small). If the above-mentioned yield point exists in a portion outside the range of use, there is no particular problem, but if the pins 16 and 16 incorporated in the universal joint 6 generally used for steering devices are made of heat-resistant synthetic resin. , This yield point appears within the usable range.

When the yield point appears in the use range in this way, the compression amount of one pin 16 of the pair of pins 16, 16 provided on the opposite side in the axial direction becomes the compression amount of the other pin 16. Compared to each other, they are likely to differ greatly. That is, due to an unavoidable error in manufacturing, when the bearing cups 10 and 10 are pushed into the circular holes 9 and 9, the small diameter portion 17 of the pin 16 (for example, the upper side in FIG. 12) becomes the yield point. Before reaching, the small diameter portion 17 of the other pin 16 (for example, the lower side of FIG. 12) may reach the yield point. In such a case, the pin 1 of the one pin 1 is accompanied by the pushing operation which is continued after the small diameter portion 17 of the other pin 16 reaches the yield point.
The compression amount of the other pin 16 is larger than the compression amount of 6. The yield points of the small-diameter portions 17, 17 of the pair of pins 16, 16 are very close to each other, but when they are far apart, the compression amount of the pair of pins 16, 16 is as shown in FIG. However, it will be very different. As a result, the compression amount of the seal ring 14 corresponding to the other pin 16 is large (excessive), and the compression amount of the seal ring 14 corresponding to the one pin 16 is small (insufficient).

The variation in the amount of compression of the seal rings 14, 14 due to the bias of the amount of compression of the pins 16, 16 is as follows.
Insufficient durability of the seal ring 14 (when the compression amount is excessive) or deterioration of the sealing performance (when the compression amount is insufficient)
Invite. Therefore, regardless of variations in the compression characteristics of the pins 16 and 16, the pins 16 provided on the opposite side in the axial direction,
In order to prevent the amount of compression of 16 from varying, the cross shaft 8
It is conceivable that the bearing cups 10 and 10 are pushed in while fixing the. That is, of the four shafts 11, 11 forming the cross shaft 8, two shafts 11, 11 which are not pushed (for example, arranged in the horizontal direction in FIG. 12) are supported and fixed. Perform the pushing work. If the pushing operation is performed in this manner, the above-mentioned variation in the amount of compression can be prevented, but the work for fixing the cross shaft 8 is required, which complicates the manufacturing process of the universal joint 6 and reduces the manufacturing cost of the universal joint 6. I will raise it. The universal joint of the present invention was invented in view of such circumstances.

[0015]

The universal joint of the present invention, like the conventional universal joint described above, has a pair of yokes each formed in a bifurcated shape, and concentric with each other at both ends of each yoke. The formed circular holes, the bottomed cylindrical bearing cups fitted and fixed inside the circular holes with their openings facing each other, and the four shafts each formed in a cylindrical shape. A cross shaft having a shaft portion and each shaft portion inserted in each of the bearing cups, a radial bearing provided between an inner peripheral surface of each bearing cup and an outer peripheral surface of each shaft portion, and A seal ring provided between the base of the cross shaft and the opening of each of the bearing cups, and formed inside the cross shaft in the state of opening in the end face of each of the shafts in the axial direction. Insert the bottomed insertion hole and insert it into each insertion hole so that one end of each , And the other ends and a synthetic resin pin abuts the bottom surface of each bearing cup.

Particularly, in the universal joint of the present invention, each of these pins has a linear polyphenylene sulfide resin content of 80 to 98 % by weight (hereinafter referred to as "linear PPS").
And 1 to 10% by weight of fibrous filler , aramid fiber
And 1 to 10% by weight of spherical isotropic particle filler .
It is composed of amorphous carbon particles . Also, preferably,
As described in claim 2, as the aramid fiber, a long
With a diameter of 5 mm or less and a diameter of 0.1 to 20 μm
The above isotropic amorphous carbon particles have a diameter of 0.1 to
Those of 50 μm are used.

More preferably , as described in claim 3,
A large cross-sectional area portion formed at both axial end portions as the pins and insertable into the insertion holes, and provided between the large cross-sectional area portions in series in the axial direction. Also, those having a small cross-sectional area portion and an interrupted area portion are used.

The linear PPS used in the present invention has no crosslinking agent or branching agent added during polymerization. Further, after the polymerization, it was not subjected to heat treatment at high temperature. Therefore, it is a high polymer that does not contain a cross-linking or branching structure in the molecule. As such a linear PPS, those produced by the production method disclosed in JP-A-61-7332 or JP-A-61-66720 can be preferably used. The melt viscosity, which is a measure of the molecular weight of the linear PPS produced by this method, has a resin of 310 ° C. and a shear rate of 200 (seconds).
It is 500 poises or more when measured at ^-1 . As such a PPS, for example, "Fortron KPS (registered trademark)" manufactured by Kureha Chemical Industry Co., Ltd. can be used.

Examples of the aramid fiber used in the present invention include highly heat resistant aramid fibers such as Kevlar or Nomex manufactured by DuPont and Technora or Conex manufactured by Teijin. In addition, the fibrous filler Der
Is in the form of that aramid fibers, in the 10mm or less in length (preferably 5mm or less), it is desirable that a diameter of 0.1 to 20 [mu] m. The reason for this is that the fibrous filler , Alami
This is because the work of melt-kneading the dough fiber and the straight-chain PPS and further performing injection molding can be easily performed. Also, Arami
In order to improve the affinity between the dough fiber and the linear PPS and improve the quality of the obtained pin, the aramid fiber is treated with a coupling agent or the like, or the aramid fiber and the linear PPS are treated. It is desirable to directly add the above-mentioned coupling agent or the like when blending.

Furthermore, the spherical isotropic indeterminate used in the present invention
The shape of the shaped carbon particles is 0.1-50 μm in diameter.
Something is desirable. The reason for this is to ensure the dispersibility in the case of melt-kneading with the linear PPS, the ease of injection molding, and the smoothness of the pin which is a molded product. Furthermore,
In order to improve the affinity between these spherical isotropic amorphous carbon particles and linear PPS, these spherical isotropic amorphous carbon particles are used.
Or process the child with a coupling agent or the like, or of these spherical
When the isotropic amorphous carbon particles and the linear PPS are blended, it is desirable to directly add the coupling agent or the like. Incidentally, the spherical isotropic amorphous carbon particles are spherical phenol cured products produced by the method disclosed in, for example, JP-A-58-17114 and JP-A-57-177011, using phenols. It is a particle having an average particle diameter of 1 to 30 μm, which is obtained by baking the particle at a temperature of 500 ° C. or higher in an inert atmosphere and carbonizing. An example of such particles is "Bellpearl-C (registered trademark)" manufactured by Kanebo.

Further, the linear PPS of the present invention is filled with fibrous material.
Aramid fiber as a material and spherical isotropic as a particulate filler
The blending ratio when blending with the amorphous carbon particles is 80 to 98% by weight of linear PPS and 1 to 10 of aramid fiber .
%, And the isotropic amorphous carbon particles are 1 to 10% by weight. The reason for this is as follows. A is a fibrous filler
The ramid fiber is added to improve mechanical properties such as impact strength and compressive strength. However, when the amount of the aramid fiber added is less than 1% by weight, improvement of these mechanical properties can hardly be expected. On the other hand, 1 part of the above aramid fiber
If it is added in an amount of more than 0% by weight, the moldability of the linear PPS containing the aramid fiber is deteriorated, the compression fracture strain is further lowered, and the compression set is increased. Therefore, the amount of the aramid fiber added is set within the range of 1 to 10% by weight. Also, isotropic amorphous that is a particulate filler
Carbon particles are added to improve wear resistance.
When the amount of the isotropic amorphous carbon particles added is less than 1% by weight, improvement in wear resistance can hardly be expected. On the other hand, even if the above-mentioned isotropic amorphous carbon particles are added in an amount of more than 10% by weight, no remarkable improvement in wear resistance is observed, but rather deterioration in formability and reduction in compression fracture strain are caused. Will end up. Therefore, the amount of the isotropic amorphous carbon particles added is set within the range of 1 to 10% by weight.

If necessary, various fillers or fillers other than those mentioned above, and further various stabilizers may be blended within the range not impairing the object of the present invention. However, it is generally desirable that the total amount thereof be 10% by weight or less of the total amount. Such fillers (agents) and stabilizers include organic fillers, inorganic fillers, toughness improvers (e.g. elastomers), antioxidants, UV absorbers, light protectors, heat stabilizers, flame retardants, electrostatic charge There are inhibitors, peroxide decomposers, fluidity improvers, non-tackifiers, release agents, nucleating agents, plasticizers, solid lubricants, pigments, dyes and the like.

Furthermore, the method of blending the raw materials used in the composition of the pin constituting the universal joint of the present invention is not particularly limited. For example, linear PPS, aramid fiber, spherical
A raw material such as isotropic amorphous carbon particles , Henschel mixer,
It is possible to employ a method of premixing with a dry mixer such as a ribbon blender or a tumbler mixer, and then supplying the mixture to a melt mixer. As the melt mixer, any device such as a single-screw or twin-screw extruder, a mixing roll, a pressure kneader, a Banbury mixer, and a Brabender plastograph can be used. The melt-mixed material is formed into pellets, for example, and is molded into a predetermined shape as a pin of a universal joint by an ordinary screw-in-line type injection molding machine or the like. Further, the molding conditions are not particularly limited, and it may be carried out under normal molding conditions for the linear PPS.

[0024]

The universal joint of the present invention having the above-described structure serves to transmit a rotational force between a pair of shafts that do not exist on the same straight line, and each pin has a rear end of the insertion hole and a bearing cup. The effect of restricting the compression amount of the seal ring within an appropriate range by stretching the seal ring with the inner surface is similar to that of the conventional universal joint described above.

In particular, the pin constituting the universal joint of the present invention uses linear PPS having heat resistance of 150 ° C. or more, excellent toughness, and small compression set in a high temperature atmosphere. Even if a sudden compressive load or excessive compressive strain acts, it will not be damaged. Also, since the permanent deformation is small, even if there is a difference in the compression amount of each pin during the assembly of the universal joint, a gap is unlikely to be created between the protruding surface of the pin and the bottom surface of the bearing cup when the assembly is completed. . Furthermore, fibrous filling
Aramid fiber as a material and spherical isotropic as a particulate filler
Since the amorphous carbon particles are added , all of the compressive strength, impact resistance and abrasion resistance are extremely excellent without lowering the toughness.

Furthermore, in the case where each of the above pins is constructed by arranging a large cross-sectional area portion, an interruption area portion and a small cross-sectional area portion in series,
The relationship between the compression load and the compression amount of each of these pins can be smoothed. That is, when a compressive load is applied to each of these pins, the small cross-sectional area portion is first deformed, and then the interrupted area portion is deformed. Each of the pair of pins has been compressed to some extent at the time when the interrupted area portion begins to deform. Before the deformation of the interrupted area portion is started, the small cross-sectional area portion, which is easily deformed, passes through the yield point of the straight-chain type PPS, but after the small cross-sectional area portion is sufficiently compressed, The suspended area portion starts to be compressed by further applying a compressive load. In other words, after the breakdown of the small cross-sectional area portion, the breakdown of the interrupted area portion continues to occur.
As a result, the apparent characteristics of the pins as a whole are smooth characteristics such that there is no yield point, and there is no large difference in the amount of compression of the interrupted area portions of the pair of pins.

[0027]

EXAMPLES First, an experiment conducted to confirm the effect of the present invention will be described. The present invention is not limited to the embodiments described below. The raw materials used in Examples and Comparative Examples are as follows. The code in parentheses after each raw material name is the abbreviation of the raw material. -Linear PPS (L-PPS): "Fortron (registered trademark) KPS W-214" manufactured by Kureha Chemical Industry Co., Ltd.-Branched PPS (B-PPS): "Ryton (registered trademark)" manufactured by Philips Oil Co., Ltd. P4 "-Polyacetal copolymer (POM):" Duracon (registered trademark) M90-44 "manufactured by Polyplastics Co., Ltd.-Nylon 66 (PA66):" Amilan (registered trademark) 3001-N "manufactured by Toray Co., Ltd.-Glass fiber ( GF): “M” manufactured by Asahi Fiber Glass Co., Ltd.
F-KAC (diameter 13 μm, length 50 to 120 μm) ”-Aramid fiber (ArA):“ Conex (registered trademark) cut fiber (diameter 2 denier, length 0.6 mm) ”manufactured by Teijin Ltd. Amorphous amorphous carbon particles (BP): "Bellpearl (registered trademark) C-800 (diameter 1 to 30 µm, manufactured by Kanebo Co., Ltd.
m) ”・ Graphite (Gr):" BF "manufactured by Chuetsu Graphite Co., Ltd.

By mixing the above raw materials in the proportions shown in the following Table 1, a total of 12 types of samples, 3 types for the examples of the present invention and 9 types for the comparative examples deviating from the present invention, were obtained. Created.

[0029]

[Table 1]

After premixing Examples 1 to 3 and Comparative Examples 1 to 9 shown in Table 1 above with a Henschel mixer manufactured by Mitsui Miike Seisakusho, a twin-screw extruder (PCM-
30) and kneaded and extruded to form a strand. Then, this strand was continuously cut immediately after extrusion to obtain pellets having the composition shown in Table 1 above.
Then, the pellets were molded into a test piece having a shape and a size according to each test method described below by using an injection molding machine (MODEL SIM-4749) manufactured by Technoplus. And various physical properties of the obtained test piece were measured based on the following test methods. The measurement results are shown in Table 1 above together with the composition.

Heat Aging Test Using 12 kinds of raw materials having the composition shown in Table 1,
ASTM I type dumbbell tensile test pieces were prepared and
A heat aging test was performed for 2000 hours in a hot air circulation type constant temperature bath at 0 ° C. Based on ASTM D638, the tensile strength and tensile elongation of each test piece were measured, and the retention rate was calculated for each of the tensile strength and tensile elongation. The results are shown in the first column and the second column in the column of physical properties in Table 1. The values of the results shown in Table 1 were calculated by the following formula. Retention rate (%) = {(physical property value after test) / (initial physical property value)} × 100

Impact Test I-zod impact test pieces were prepared from the above 12 kinds of raw materials, and the I-zod impact strength was measured according to ASTM D256. The measurement results are shown in the third column of the physical properties column of Table 1.

Compressive Fracture Strain Test Using the above 12 kinds of raw materials, diameter 12.7 mm, length 2
A cylindrical test piece of 5.4 mm was prepared, and ASTM D695
The compressive fracture strain was measured based on. The measurement results are shown in the fourth column of the physical properties column of Table 1. The results of the tests shown in Table 1 were calculated by the following formula. Compressive fracture strain (%) = {25.4- (test piece length at compressive fracture) /25.4} x 100

Compression set test Using the above 12 kinds of raw materials, diameter 12.7 mm, length 2
A 5.4 mm cylindrical test piece was prepared. Then, each test piece was left in a hot air circulation type constant temperature bath at 150 ° C. for 1 hour while being loaded with 10% compressive strain in the lengthwise direction, and then each test piece was taken out and after 30 minutes passed. The length of each test piece was measured to determine the compression set. The measurement results are shown in the fifth column of the physical properties column of Table 1. The results shown in Table 1 were calculated by the following formula. The numerical value of 2.54 corresponds to a compressive strain of 10%. Compression set (%) = {(25.4-length of test piece after test)
/2.54} x 100

Friction and abrasion test A disc-shaped test piece having a diameter of 30 mm and a thickness of 3 mm and an inner diameter of 20 mm, an outer diameter of 25.6 mm and a height of 1 were prepared from the above 12 kinds of raw materials.
A 5 mm hollow cylindrical mating material test piece (S45C, sliding surface roughness 0.8 Ra, hardness HRC20) was prepared. Heat resistant grease (ENS grease manufactured by Nippon Oil Co., Ltd.) on both of these test pieces
Was applied thinly, and using a Suzuki type friction and wear tester, sliding speed was 20 m / min, load was 80 kgf / cm ² , and ambient temperature was 150 ° C.
After operating for 5 hours under the conditions, the friction coefficient and specific wear amount (mm
³ / kgf · km) was calculated. The measurement results are shown in the sixth to seventh columns in the physical properties column of Table 1.

As is clear from the description of Table 1 showing the results of the above-mentioned tests, Examples 1 to 3 and Comparative Examples 7 to 9 were obtained.
Shows good heat aging resistance because it uses linear PPS as the base resin. Moreover, Examples 1-3 and Comparative Examples 7-
Comparing 9 with Comparative Examples 4-6, Examples 1-3 and the ratio
Comparative Examples 7 to 9 exhibit good compression set resistance in a high temperature environment. Further, when comparing Comparative Example 7 and Example 1 with Comparative Examples 2 and 3, it can be seen from Comparative Example 7 and Example 1 that the impact strength values are improved, and thus the same PPS is obtained. Also, the toughness is improved by using the linear PPS instead of the branched PPS. Moreover, Examples 1-3 and Comparative Examples 7-
By comparing 9 with Comparative Example 1, good compression characteristics are exhibited when the filling amounts of the fibrous filler and the particulate filler are both 10% by weight or less, but the filling amount increases. (15% by weight in Comparative Example 1), it can be seen that the compression characteristics deteriorate. Furthermore, also in Examples 1 to 3 and Comparative Examples 7 to 9 ,
Example 1 containing a fibrous filler and a particulate filler
3 and Comparative Examples 8 and 9 show excellent wear resistance. In particular, Examples 1 to 3 use aramid fibers, which are heat-resistant organic fibers, as the fibrous filler and spherical isotropic amorphous carbon particles as the particulate filler, so that general reinforcement is achieved. It can be seen that it exhibits better wear resistance than glass fiber, which is a fiber, and non-spherical graphite, which is a typical solid lubricant, is added.

As described above, the composition of the pin incorporated in the universal joint of the present invention has excellent compression characteristics and wear resistance without impairing the heat resistance and toughness of the linear PPS. Therefore, when this composition is molded into a pin and assembled in a universal joint, the compression set under a high temperature atmosphere is small, and when a sudden compression load is applied or the compression amount of the seal ring is properly adjusted. Therefore, as shown in the concrete structure below, the pin is provided with a small cross-sectional area, and even if the amount of compression of a part of this pin becomes excessive, this small cross-sectional area may be damaged. Absent. Moreover, since the permanent deformation of the pin is small and the wear resistance is good, the durability in a high temperature atmosphere is improved. Therefore, it is possible to improve the durability and reliability of the universal joint that is used for a long time in a high temperature atmosphere such as in the engine room.

Next, an example of a specific structure of the universal joint of the present invention will be described. It should be noted that the present invention provides the best results by carrying out the structure shown in the embodiments described below, but as long as the constituent material of the pin satisfies the composition described in the claims, it is not necessarily shown. It is not limited to the examples. 1 to 4 show a first embodiment relating to a specific structure. The feature of the embodiment relating to the specific structure is that the pins 16a, 16a are composed mainly of straight-chain PPS, and a pair of seal rings 14 are provided at positions opposite to the cross shaft 8 in the axial direction. Each of the pins 16a, 16a so that the compression amount of each of the fourteen is within an appropriate range.
The point is that the shape of the is devised. Since the structure and operation of the other parts are the same as the conventional structure described above, the same parts are designated by the same reference numerals to omit or simplify the overlapping description, and the characteristic parts of the embodiment will be mainly described below. . Although the universal joint 6 shown in FIG. 1 does not have a vibration isolation structure, it is free to have a vibration isolation structure as shown in FIG.

Large linear cross-section areas 21 and 21 are formed on both ends of the linear PPS pins 16a and 16a in the axial direction (vertical direction in FIGS. 1 to 3). This large cross-section area 2
The outer diameters of 1 and 21 are the four shaft portions 1 forming the cross shaft 8.
The inner diameters of the insertion holes 15 and 15 opened at the central portions of the end faces 1 and 11 are the same as or slightly smaller than the inner diameters. Thus each large-sectional area portion 21 and 21, each of the insertion holes 1
It can be inserted into 5 and 15. Also, the pins 16a, 1
At the central portion in the axial direction of 6a, a small cross-sectional area portion 2 having a cylindrical shape is also provided.
Forming 2. Further, interrupted area portions 23 and 23 are provided between both ends in the axial direction of the small sectional area portion 22 and the large sectional area portions 21 and 21, respectively.

Each of the pins 16a having such a shape,
16a are inserted into the insertion holes 15 and 15 formed in the shaft portions 11 and 11, respectively, and are stretched between the rear ends of the insertion holes 15 and 15 and the bottom surfaces of the bearing cups 10 and 10. In the case of the illustrated embodiment, each of the above-mentioned interruption area portions 23,
The rib 2 extends from 23 to the large cross-section areas 21 and 21.
0 and 20 are formed. Therefore, the insertion holes 15,
The pins 16a and 16a inserted into the shaft 15 do not accidentally fall off before the bearing cups 10 and 10 are mounted. Further, linear PPS constituting the respective pin 16a, and 16a, so has an excellent impact strength (toughness) as compared to branched PPS, when inserting each pin 16a, and 16a into the insertion hole 15, 15 In addition, the small cross-section area is not broken.

In the case of the universal joint of this embodiment including the pins 16a and 16a as described above, the relationship between the compression load and the compression amount of each of the pins 16a and 16a can be made smooth, and A pair of pins 16a provided on opposite sides of the direction,
The compression amount of 16a can be made substantially equal. That is, the yoke 7
With the work of pushing the bearing cups 10 and 10 into the circular holes 9 and 9 formed in the a and 7b, respectively,
When a compressive load is applied to each of the pins 16a, 16a, first, the small cross-sectional area portion 22 is compressed and deformed. Then, in the state in which the small cross-sectional area portion 22 has been compressed and deformed to some extent, the interrupted area portions 23, 23 start compressive deformation. still,
While the small cross-sectional area portion 22 is compressed and deformed, the interrupted area portions 23 and 23 are also slightly compressed and deformed.
It is far less than the amount of deformation.

Therefore, at the time when each of the interrupted area portions 23, 23 starts to be substantially compressed and deformed, the pair of pins 16 is formed.
Both a and 16a are compressed to some extent by the compressive deformation of the small cross-sectional area portion 22. Incidentally, before the compression deformation of each of the interrupted area portions 23, 23 is started in this way, the small cross-sectional area portion 22 passes through the yield point of the linear PPS.
It should be noted that, at the stage when the compression deformation of each of the interrupted area portions 23, 23 is started, the compression amount of each of the pins 16a, 16a as a whole has not reached the use range.

In other words, each of the interrupted area portions 23, 2
The small cross-sectional area portion 22 is almost completely compressed and deformed at the time point 3 is substantially compressed and deformed. Accordingly, the pair of pins 16a, even if there is a difference in yield point of the small cross-sectional area portion 22 of the 16a, a pair of in pushing completion of the bearing cups 10, 10, the difference is above the pins 16a, the overall 16a Has almost no effect on the amount of compression.

After the small cross-sectional area portion 22 is completely compressed and deformed, the interrupted area portions 2 of the pair of pins 16a, 16a are formed.
When the compression work is further applied to the bearings 3 and 23 as the pair of bearing cups 10 and 10 are continuously pushed, the bearings 3 and 23 are substantially compressed. Then, the pin 16 of the pair
By compressing the interruption area portions 23, 23 in addition to the small cross-sectional area portions 22, a and 16a are respectively compressed by a predetermined amount as a whole. In other words, each of the pin 16a,
16a is compressed as a whole by the amount of compression in the small cross-sectional area portion 22 plus the amount of compression in the interrupted area portions 23, 23.

Of the total compression amount of each pin 16a, 16a, the compression amount of the small cross-sectional area portion 22 occupies a certain degree, so that the compression of the interruption area portions 23, 23 is performed. The quantity will be limited. Therefore, the compression of each of the interrupted area portions 23, 23 does not pass the yield point, or even if it passes, it passes only just before the pushing operation of the pair of bearing cups 10, 10 is completed. Therefore, there is no great difference in the amount of compression of the interruption area portions 23, 23 of the pair of pins 16a, 16a. This way, these 1
Since the pair of pins 16a, 16a further compress the interrupted area portions 23, 23 in a state in which the amount of compression by the small cross-sectional area portion 22 is secured, the apparent compression characteristics of these pins 16a, 16a are as shown in FIG. As shown by the solid line c in FIG.

Therefore, the linear PP having excellent heat resistance
As in the case of using S and polyacetal resin, a pair of pins 16 present at axially opposite positions
It is possible to prevent a large difference in the compression amounts of a and 16a.
As a result, the compression amounts of the pair of seal rings 14, 14 provided at axially opposite positions can be kept within the appropriate range. Therefore, one of the seal rings 14 will not be excessively compressed to lower the durability, or the compression amount of the seal ring 14 on the opposite side will not be insufficient and the sealing performance will not be impaired.

In order to make the apparent compression characteristics of the linear PPS pin 16a smooth, this pin 1
It was confirmed by an experiment conducted by the present inventor that the size of 6a should be restricted as follows. First, when the interval D 21 between the large cross-sectional area portions ₂₁ , 21 formed at both ends in the axial direction is 1.0, the length dimension L ₂₂ of the small cross-sectional area portion ₂₂ is 0.25 to 0.4.
Within the range (L ₂₂ = (0.25 to 0.4) D ₂₁ ).
The absolute value of the length dimension L ₂₂ is smaller than the compression amount L ₀ required for the pin 16a as a whole (L ₂₂ <L ₀ ). In short, even if the small cross-sectional area portion 22 is completely compressed (it requires an extremely large load to be compressed further),
The length dimension L ₂₂ is regulated so that the compression amount does not reach the required compression amount L ₀ . Further, the length dimensions of the interruption area portions 23, 23 existing on both sides in the axial direction of the small sectional area portion 22 are made equal to each other. Furthermore, each of these interruption area portions 23,
When the cross-sectional area S ₂₃ of ₂₃ is 1, the small cross-sectional area portion 2
The cross-sectional area S ₂₂ of 2 is set within the range of 0.5 to 0.7 (S ₂₂
= (0.5~0.7) S _23).

Next, FIGS. 5 to 7 show a second embodiment having a specific structure. In the case of this embodiment, reinforcing ribs 24, 24 extending in the axial direction are formed at four positions on the outer peripheral surface of the small cross-sectional area portion 22 of the linear PPS pin 16b. In the case of the present embodiment, such reinforcing ribs 24, 24
Due to the existence of the above, when the pin 16b is press-fitted into the insertion hole 15, the small cross-sectional area portion 22 is less likely to bend.
In the case of this embodiment, the cross-sectional area of the small cross-sectional area portion 22 includes these reinforcing ribs 24, 24. That is, the above-mentioned cross-sectional area regulation formula (S ₂₂ = (0.5 to 0.7) S ₂₃ ) is
It is necessary to fill with a cross-sectional area including the cross-sectional areas of the reinforcing ribs 24, 24. The number of the reinforcing ribs 24, 24 is the same as that of the pin 1
There is no particular restriction on the function of 6b. However, if the number of the reinforcing ribs 24, 24 is 2 or 4, and the reinforcing ribs 24 are arranged at equal intervals in the circumferential direction, there is no undercut portion during injection molding, and it is possible to mold with a simple two-split mold, which is advantageous. is there. Other configurations and operations are similar to those of the above-described first embodiment.

Next, FIGS. 8 to 9 show a third embodiment of the present invention. In the case of this embodiment, the cross-sectional shape of the small cross-sectional area portion 22 of the linear PPS pin 16c is square. Other configurations and operations are similar to those of the above-described first embodiment. In each of the illustrated embodiments, the small cross-sectional area portion 22 is sandwiched by the pair of interrupted area portions 23, 23 from both sides in the axial direction, but this is not always necessary in order to obtain the effect of the present invention. It does not have to be such an arrangement. In short, at least one small cross-sectional area portion 22 and at least one interrupted area portion 23 may be provided in series in the axial direction between the large cross-sectional area portions 21, 21 at both ends. However, if the arrangement as in the illustrated embodiment is adopted, there is an effect that the step difference between the cross-sectional area portions adjacent to each other in the axial direction can be reduced and the deformation due to molding can be reduced.

The pins 16a to 16c incorporated into the concrete structures as in the above-mentioned respective examples are made of general heat-resistant synthetic resin compositions as shown in Table 1 as Comparative Examples 2 to 3, for example. In the case of a certain branch type PPS, due to insufficient toughness, the compression set of the small cross-section area portion 22 which is easily deformed as described above becomes excessive, which may lead to damage of the pin. Further, in the case of being made of polyacetal or nylon 66 alone, the sliding contact between the bottom surfaces of the bearing cups 10 and 10 and the protruding surfaces 19 of the pins 16a to 16c causes the protruding surfaces 19 and 19 to move. As a result, remarkable wear is caused, and as a result, the protruding surface 1 of each of the pins 16a to 16c is
There may be a gap between the bearings 9, 19 and the bottom surface of the bearing cups 10, 10. When a gap is generated due to such wear, as in the case where the pin is softened and deformed,
An undesirable phenomenon such as rattling occurs. In the case of the present invention, since the pins 16a to 16c are composed of a composition mainly composed of a linear PPS having excellent toughness,
It is possible to effectively prevent damage to the pin having the small cross-sectional area portion 22. Furthermore, wear is prevented by adding an appropriate filler,
It is possible to prevent rattling due to wear.

[0051]

Since the universal joint of the present invention is constructed and operates as described above, the following effects (1) to (3) can be obtained at the same time. Since sufficient heat resistance can be ensured by using the linear PPS pins, rattling and other problems are less likely to occur even after long-term use in a high temperature environment such as in an engine room. Since the amount of compression of the seal ring can be made appropriate, the durability and seal performance of this seal ring can be secured.
Since it does not require troublesome work such as fixing the cross shaft at the time of assembly, the product yield is improved and the price can be reduced.

[Brief description of drawings]

FIG. 1 is a partially cut side view showing a first embodiment of a specific structure of the present invention.

FIG. 2 is a view corresponding to the AA cross section of FIG. 1, showing a state in which only one yoke is mounted on the cross shaft.

FIG. 3 is an enlarged side view of a pin used in the first embodiment.

4 is a sectional view taken along line BB of FIG.

FIG. 5 is a partially enlarged cross-sectional view showing a second embodiment of the specific structure of the present invention in a state where the bearing cup is being pushed.

FIG. 6 is an enlarged side view of a pin used in the second embodiment.

7 is a cross-sectional view taken along the line CC of FIG. 6 with a part omitted.

FIG. 8 is an enlarged side view of the pin showing the third embodiment of the specific structure of the present invention.

9 is a cross-sectional view taken along line DD of FIG. 8 with a part thereof omitted.

FIG. 10 is a perspective view of a steering device incorporating a universal joint.

FIG. 11 is a partially cut side view showing an example of a conventionally known universal joint.

FIG. 12 is a view similar to FIG. 2, showing a conventional universal joint.

FIG. 13 is a side view showing a first example of a conventionally used pin.

FIG. 14 is a side view showing the second example.

FIG. 15 is a diagram showing the relationship between the compressive load applied in the axial direction of the pin and the amount of compression applied in the axial direction of the pin.

[Explanation of symbols]

1 steering wheel 2 steering shaft 3 Intermediate shaft 4 steering gear 5 input shaft 6 universal joints 7a, 7b York 8 cross axis 9 circular holes 10 Bearing cup 11 Shaft 12 radial bearing 13 base 14 seal ring 15 insertion holes 16, 16a, 16b, 16c Pin 17 Small diameter part 18 Large diameter part 19 protruding surface 20 ribs 21 Large cross-section area 22 Small cross-section area 23 Suspended area section 24 Reinforcing rib

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-64-79419 (JP, A) JP-A-60-188460 (JP, A) JP-A-62-240351 (JP, A) JP-A-3- 287662 (JP, A) JP-A-3-292366 (JP, A) Actually open 3-7534 (JP, U) Actually open 57-61228 (JP, U) Actual public 64-2982 (JP, Y2) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16D 3/26-3/41

Claims (5)

(57) [Claims] 1. A pair of yokes each formed in a bifurcated shape, circular holes concentrically formed at both ends of each yoke, and the circular holes in the state where the openings are opposed to each other. A bottomed cylindrical bearing cup that is fitted in and fixed to the inside, and four shaft portions that are each formed in a cylindrical shape, and each shaft portion is a cross shaft that is inserted into each of the bearing cups. A radial bearing provided between an inner peripheral surface of each bearing cup and an outer peripheral surface of each shaft portion, and a seal ring provided between a base portion of the cross shaft and an opening portion of each bearing cup. A bottomed insertion hole formed in the axial direction inside the cross shaft while opening at the end face of each shaft portion, and one end of each insertion hole inserted into each insertion hole. Made of synthetic resin with the other end abutting against the bottom of each bearing cup. In the universal joint including the pins, each of the pins is 80 to 98 % by weight of linear polyphenylene sulfide resin and 1 to 1 which is a fibrous filler.
10% by weight of aramid fiber and particulate filler 1 to
A universal joint comprising 10% by weight of spherical isotropic amorphous carbon particles . 2. The flexible structure according to claim 1, wherein the aramid fiber has a length of 5 mm or less, a diameter of 0.1 to 20 μm, and the isotropic amorphous carbon particles have a diameter of 0.1 to 50 μm. Fittings. 3. Each pin is formed at both ends in the axial direction,
A large cross-sectional area portion that can be inserted into each insertion hole and a small cross-sectional area portion and an interrupted area portion that are provided in series between the large cross-sectional area portions in the axial direction and in series with each other are provided. , Claim 1
The universal joint described in any one of 2. 4. When the distance between the large cross-sectional area portions formed at both axial ends of each pin is 1, the length dimension of the small cross-sectional area portion is within the range of 0.25 to 0.4. Each pin is made smaller than the required compression amount as a whole, and the length dimensions of the interruption area portions existing on both sides in the axial direction of the small cross-sectional area portion are equal to each other
Moreover, when the cross-sectional area of each of these suspended area portions is 1,
The universal joint according to claim 3, wherein the cross-sectional area of the small cross-sectional area portion is within the range of 0.5 to 0.7. 5. The universal joint according to claim 1, which is used in a state where it is incorporated in a steering device of an automobile.