JPH051028U - Trunnion in tripod type constant velocity joint - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the durability of the trunnion of a tripod type constant velocity joint. [Constitution] Three journals 3 are attached to the outer diameter surface of the boss 2.
Form at intervals of 20 °. A large number of teeth 4 for transmitting torque are provided on the inner diameter surface of the boss portion 2. A toothless portion 6 in which a plurality of the teeth 4 are removed is formed on the inner diameter surface of the cylindrical portion 5 between the journals 3 and the whole is hardened to increase the hardness. The shaft is press-fitted into the hardened trunnion, the torque is transmitted at the engaging portion of the teeth formed on the outer periphery of the shaft and the teeth of the trunnion, and the cylindrical portion 5 having the toothless portion 6 on the inner periphery is not loaded. To do so.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to a trunnion in a tripod type constant velocity joint.

[0002]

[Prior Art]

 As shown in FIG. 5, the tripod type constant velocity joint has three troughs 12 axially formed on the inner diameter surface of the outer ring 11 at intervals of 120 °, and is installed inside the outer ring 11. Three journals 14 are provided on the outer diameter surface of 13 at intervals of 120 °, and rollers 15 rotatably attached to the outside of each journal 14 are fitted into the track grooves 12, and the track grooves 12 The rotation torque is transmitted to the outer ring 11 between the trunnions 13 by the engagement between the side surface and the roller 15.

Here, as shown in FIGS. 3 and 4, the trunnion 13 has a structure in which teeth 17 for torque transmission such as serration are formed on an inner diameter surface of a boss portion 16 having three journals 14. As shown in FIG. 5, the teeth 17 are engaged with teeth 19 on the outer circumference of a shaft 18 press-fitted inside the trunnion 13, and torque is transmitted at the engaging portions of the teeth 17, 19. ..

Since the trunnion 13 is required to have strength, it is usually hardened to increase its hardness.

[0005]

[Problems to be solved by the device]

 By the way, in the trunnion 13, since the thickness of the forming portion of the journal 14 is large and the thickness of the cylindrical portion 20 between the journals 14 is small, the shrinkage amount in the cooling process after quenching is in the circumferential direction of the boss portion 16. The inner diameter surface of the cylindrical portion 20 that is not uniform and has a large amount of contraction is deformed inward by a few tens of μm more than the inner surface of the journal formation site, and as shown by the chain line (a) in FIG. Transforms into a rice ball shape.

For this reason, when the shaft 18 is inserted into the trunnion 13 and coupled to each other, if the fit is a tight fit, the interference of the teeth 17 on the inner diameter surface of the cylindrical portion 20 becomes smaller than that of the teeth 17 on the journal forming portion. If the clearance fit is larger than the interference fit and the clearance fit fits, the clearance of the teeth 17 in the cylindrical portion 20 is smaller than the clearance of the teeth 17 in the journal forming portion, and the teeth 17 on the inner diameter surface of the cylindrical portion 20 during torque transmission. However, there is a problem that the thin cylindrical portion 20 is weak in strength.

The present invention aims to solve the above problems and to improve the durability of the cylindrical portion.

[0008]

[Means for Solving the Problems]

 In order to solve the above problems, in the present invention, three journals are provided on the outer diameter surface of the boss portion at intervals of 120 °, and a large number of teeth for torque transmission are provided on the inner diameter surface of the boss portion. That is, a structure in which a toothless portion in which a plurality of teeth are removed is provided on the inner diameter surface of the cylindrical portion between the journals is adopted.

[0009]

[Action]

 According to the above structure, the shaft teeth having the torque transmitting teeth on the outer periphery are press-fitted into the trunnion to couple the trunnion with the shaft, so that the shaft teeth are engaged with the teeth on the inner diameter surface of the journal forming portion. Then, the torque is transmitted at the engaging portion. Therefore, no load is applied to the cylindrical portion, and it is possible to prevent damage to the cylindrical portion.

[0010]

【Example】

 An embodiment of this invention will be described below with reference to FIGS. 1 and 2.

As shown in the figure, the trunnion material 1 has a boss portion 2, and three journals 3 are formed on the outer diameter surface of the boss portion 2 at intervals of 120 °. A large number of teeth 4 for transmitting torque are formed on the inner diameter surface of the boss portion 2, and a toothless portion 6 obtained by removing a plurality of the teeth 4 is provided on the inner diameter surface of the cylindrical portion 5 between the journals 3. ing.

The trunnion material 1 having the above structure is hardened by a quenching treatment. During cooling after the treatment, the inner diameter surface of the boss portion 2 contracts, and the amount of contraction is uneven in the circumferential direction due to the difference in thickness, and the inner diameter surface of the cylindrical portion 5 is larger than the inner diameter surface of the journal forming portion. Although deformed, the inner diameter of the toothless portion 6 of the cylindrical portion 5 is larger than the root diameter of the tooth 4, so that the inner diameter surface of the toothless portion 6 is not deformed inward more than the tooth bottom surface.

After the quenching treatment, when the shaft having teeth on the outer periphery is press-fitted into the trunnion 1 and coupled, the teeth of the shaft and the teeth 4 of the trunnion 1 engage with each other, and torque is transmitted at the engaging portion.

At this time, since there are no teeth 4 on the inner diameter surface of the cylindrical portion 5, no load is applied to the cylindrical portion 5 during torque transmission, and damage from the cylindrical portion 5 can be prevented.

[0015]

[Effect of the device]

 As described above, in the present invention, a large number of teeth for torque transmission are formed on the inner diameter surface of the boss portion, and a toothless portion is provided on the inner diameter surface of the cylindrical portion between the journals, so that the cylindrical portion during torque transmission. Since no load is applied to the cylinder, damage from the cylindrical portion can be prevented, and durability can be improved.

[Brief description of drawings]

FIG. 1 is a front view of a trunnion material used in the method according to the present invention.

FIG. 2 is an enlarged front view showing a part of the above.

FIG. 3 is a front view showing a conventional trunnion.

FIG. 4 is an enlarged front view showing a part of the above.

FIG. 5 is a vertical sectional front view of a tripod type constant velocity joint.

[Explanation of symbols]

 1 Trunnion material 2 Boss part 3 Journal 4 Teeth 5 Cylindrical part 6 Missing teeth part

Claims (1)

[Claims for utility model registration] [Claim 1] Three journals are provided on the outer surface of the boss.
A tripod type in which a plurality of teeth for torque transmission are formed on the inner diameter surface of the boss portion at intervals of 20 °, and a toothless portion with a plurality of teeth removed is formed on the inner diameter surface of the cylindrical portion between the journals. Trunnion in constant velocity joint.