JPS5819373Y2 - power transmission shaft - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a power transmission shaft, and is particularly suitable for use as a power transmission shaft in a constant velocity universal joint of a front engine, front drive type automobile, and has sufficient torsional rigidity and is lightweight. This invention relates to a power transmission shaft that is low cost and highly safe.

In general, the power transmission shaft that connects the engine rotation part and the driving wheels of automobiles, etc., has sufficient strength to withstand the usage conditions of the vehicle, and is strong enough to withstand the torsional vibrations of the entire power plant, from the engine to the tires. Appropriate torsional rigidity is required to cope with various vibration noises of vehicles.

On the other hand, in conventional power transmission shafts such as constant velocity universal joints used in so-called front engine front drive type automobiles, where the engine is mounted at the front of the vehicle and drives the front wheels, For example, as shown in Figure 1,
An intermediate shaft 6 is used that connects the telescopic constant velocity universal joint 2 at the input end and the non-retractable constant velocity universal joint 4 on the wheel side at the output end to transfer power.

Conventionally, as this intermediate shaft 6, a solid type power transmission shaft 10, which is a solid shaft having an input end 12 and an output end 14 formed therein, has been generally used, as shown in FIG.

However, the solid shaft 10 in FIG. 2 is shown without the boot mounting groove.

In an automobile using this solid type power transmission shaft 10,
In order to reduce the weight of the vehicle, many methods are being used to reduce the weight by making the diameter of the power transmission shaft as thin as possible (for example, in a small passenger car with a maximum engine torque of about 10 KP・m, the diameter is about 20 to 3 Q mm). .

However, in such a solid power transmission shaft, if the diameter of the power transmission shaft is made thinner, even if the shaft is thick enough in terms of strength, the torsional rigidity of the shaft will decrease, which will cause problems for the vehicle. This has the disadvantage that torsional vibrations are generated in the power transmission shaft during sudden acceleration or deceleration, which seriously impairs riding comfort.

In order to improve the drawbacks of such a solid type power transmission shaft, as shown in FIG. an intermediate member 20 made of thick-walled pipe that is spline-fitted to the output end member 18, and welded portions 2 at both ends.
4, a pipe-type power transmission shaft 28 made up of these intermediate materials 20 and 22 and a thin cylindrical pipe material 26 that is arc welded is coming into use.

In this pipe type power transmission shaft 28, the input end member 16
Alternatively, the reason why the output end member 18 and the pipe material 26 are not joined directly but through an intermediate material 20.22 is that the outer diameter is generally about 50 to 60 mm and the wall thickness is about 2 mm. The wall thickness of the pipe material 26 is too thin, and even if the connecting part between the person and the output member is made thicker and the connection is directly caulked, there is a possibility that the connection will easily loosen and come off. This is because it may lead to serious accidents.

Further, since the members 16 and 18 generally do not function unless they are quench-hardened, it is difficult to arc weld these members to the pipe material.

On the other hand, in order to ensure sufficient torsional rigidity, the diameter of the pipe material 26 must be considerably thicker than the diameter of the joint parts. There is a limit to the thickness of the thinned part, and we cannot expect much increase in the thickness of the thinned part.

Therefore, direct caulking is difficult in this case as well.

In this method as well, the output end members 16 and 18 are normally hardened as described above, and it is difficult to directly weld the pipe material 26 as in the previous example.

On the other hand, in the conventional example shown in FIG.
The intermediate material 20.22 bites into the serration rolled portion of 6.18 and is securely crimped and connected, and since this intermediate material 20.22 is not hardened, it can be arc welded to the pipe material 26.

However, in such conventional pipe-type power transmission shafts, when caulking the intermediate material to the joint or welding the pipe material to the intermediate material, it is easy to cause inclination or misalignment. It is extremely difficult to align the axes of both 16 and 18.

Furthermore, the cost is high due to the large number of parts and processing steps.

Furthermore, the problem is that the process control of joint quality requires considerable attention and man-hours, because the disconnection of the joint between a person, an output end member and an intermediate material, or an intermediate material and a pipe material can directly lead to a major accident while driving a car. There is a point.

On the other hand, if the intermediate material is omitted in a pipe-type power transmission shaft, in addition to the problems mentioned above, there is also the problem of loosening due to torsional torque, especially when used in a front-wheel drive axle of an automobile. There is also the problem that when the joint angle of the non-expandable constant velocity universal joint 4 attached to the wheel side becomes large, the inner diameter of the pipe expands and becomes loose due to the strong bending moment that the output end member receives.

In this case, too, it will lead to a serious accident.

Another method is to use thick-walled pipe material for pipe-type power transmission shafts and omit the intermediate material to ensure caulking. If a thicker pipe is used, there are problems in that the economic cost becomes very high and the weight reduction effect is reduced.

The present invention was made to eliminate the above-mentioned conventional drawbacks, and aims to provide a power transmission shaft that has sufficient torsional rigidity, is lightweight, low cost, and highly safe.

In the present invention, a large-diameter flange portion having a width sufficiently short relative to the entire length of the shaft is formed at least in the vicinity of the input end and the output end, which integrally connects the input end and the output end of the power transmission shaft.
By comprising an inner shaft having a small diameter at least in the middle part, and a thin outer cylinder fixedly connected to the outside of the flange part so as to connect the flange parts and cover the middle part of the inner shaft, The above objective has been achieved.

Further, the inner shaft is formed by integrally joining and fixing the flange piece and the bar material by friction welding, thereby facilitating the manufacture of the inner shaft.

Furthermore, the outer tube is crimped and connected to the outer side of the flange portion of the inner shaft by caulking the outer tube from the outside against the uneven shape formed on the outer side of the flange portion of the inner shaft. This ensures the connection between the shaft and the outer cylinder.

Further, the outer cylinder is connected to the flange portion of the inner shaft by welding, and the connection between the two is also ensured.

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

As shown in FIG. 4, the first embodiment of the present invention is an input shaft that integrally connects a power transmission shaft 29 with a shaft end 30 on the sliding joint side, which is an input end, and a shaft end 32 on the output end side. Near the end 30 and the output shaft end 32, two large diameter flange portions 34 and 36 having a width sufficiently short relative to the entire length of the shaft are formed, and the intermediate portion 3
8 is a thin-walled inner shaft 40 having a small diameter, which is fixedly connected to the outside of the large-diameter flange portion 34, 36 so as to connect the flange portions 34 and 36, and to cover the intermediate portion 38 of the inner shaft 40. It is composed of an outer cylinder 42 consisting of a cylinder.

For example, as shown in FIG. 5, the inner shaft 40 is made by friction welding a flange piece 44, 46, which is a short shaft member formed by general hot forging, and a round bar material 48. It is manufactured from an inner shaft material 49 formed by bonding and fixing.

FIG. 5 shows the shape of the inner shaft after friction welding these materials and before finishing machining.

An uneven shape 54 such as a tooth pattern or a spline is formed on the outer periphery of the large diameter flange portion 34. By caulking the outer cylinder 42 from the direction, the power transmission shaft 29 according to the present invention is completed.

Similarly, the inner shaft 40, for example, as shown in FIG.
By welding and fixing one round rod 51 and two perforated disks 52, it can be used as the material for the inner shaft of the present invention, and a cost reduction effect can be expected.

A second embodiment of the present invention is shown in FIG.

In this embodiment, the outer cylinder 42 is arc-welded at the welding part 62 without making any irregularities on the outer periphery of the large diameter flange part 58, 60 of the inner shaft 56, which has been induction hardened only in necessary parts. It is something.

The other points are the same as those of the first embodiment, so the explanation will be omitted.

A third embodiment of the present invention is shown in FIG.

In this embodiment, a large-diameter flange portion 66 is also formed at the intermediate portion 38 of the inner shaft 64, and the outer cylinder 42 is caulked also at the intermediate portion.

The other points are the same as those of the first embodiment, so the explanation will be omitted.

In this embodiment, the connection between the inner shaft 64 and the outer cylinder 42 becomes even more reliable.

In both of the above-mentioned embodiments, the present invention is applied to a power transmission shaft used as a front wheel drive axle of a front engine front drive type automobile, but the scope of application of the present invention is not limited to this, and is applicable to general use. It is clear that the present invention can be similarly applied to power transmission shafts used in industrial machinery.

As explained above, the present invention provides a power transmission shaft with a large-diameter flange portion having a width sufficiently short relative to the entire length of the shaft, at least in the vicinity of the input end and the output end, which integrally connects the input end and the output end. It is composed of an inner shaft having a small diameter at least in the middle portion thereof, and a thin outer cylinder fixedly connected to the outside of the flange portion so as to connect the flange portions and cover the middle portion of the inner shaft. Therefore, it has sufficient torsional rigidity, has a small number of parts, is lightweight and low cost, and even if the joint becomes loose, the input end and output end will not separate. , does not cause serious accidents and is highly safe.

Also, when used in front wheel drive axles of automobiles,
Since the input end and output end are integrated, even when the joint angle becomes large, it can withstand the bending moment sufficiently.Moreover, by taking sufficient corner curvature of both flanges, It has excellent effects such as being reliable.

According to the inventor's calculations, in one example where practical dimensions were set for each part, the power transmission shaft according to the present invention has torsional rigidity equal to that of a conventional pipe-type power transmission shaft when the torsional strength is the same. (In this calculation example, the torsional rigidity is about 70% higher than that of the conventional solid frame type power transmission shaft) while ensuring the torsional rigidity of
It was confirmed that a 30% weight reduction could be achieved.

Similarly, if the torsional stiffness is set to be the same,
It has been confirmed that the power transmission shaft according to the present invention can reduce the weight by about 401% compared to the conventional solid rod type power transmission shaft.

[Brief explanation of the drawing]

FIG. 1 is an overall view with a partial cross section showing an example of a conventional drive axle, FIG. 2 is a front view including a partial cross section showing an example of a conventional solid rod type power transmission shaft, and FIG. The figure is a cross-sectional view showing an example of a conventional pipe-type power transmission shaft, FIG. 4 is a cross-sectional view showing the structure of a first embodiment of the power transmission shaft according to the present invention, and FIG. FIG. 6 is a front view including a partial sectional view showing the manufacturing process of the inner shaft, FIG. 6 is a sectional view showing another manufacturing process of the inner shaft, and FIG.
FIG. 8 is a cross-sectional view showing the structure of the third embodiment. 2... Telescopic constant velocity universal joint part, 4...
Non-expandable constant velocity universal joint, 6...power transmission shaft,
29...Power transmission shaft, 12,30...
Input side shaft end, 14.32... Output side shaft end, 34
, 36, 58, 60, 66... Large diameter flange part, 38... Middle part, 40°56, 64...
...Inner shaft, 42...Outer tube, 44°46.
...Flange piece, 48...Round bar material,
51...Round bar material, 52...Perforated disk, 54...Irregular shape, 62...Welded part.

Claims (4)

[Scope of utility model registration request] (1) A large-diameter flange portion with a width sufficiently short relative to the entire length of the shaft is formed at least near the input end and output end, which integrally connects the input end and the output end, and at least the middle portion has a small diameter. connecting the inner shaft and the flange portions;
A power transmission shaft consisting of a thin outer cylinder fixedly connected to the outside of the flange so as to cover the middle part of the inner shaft. (2) The power transmission shaft according to claim 1, wherein the inner shaft is formed by integrally joining and fixing a flange piece and a bar material by friction welding. (3) Registration of a utility model in which the outer cylinder is crimped to the outside of the flange of the inner shaft by caulking the outer cylinder from the outside against the uneven shape formed on the outer periphery of the flange of the inner shaft. A power transmission shaft according to claim 1 or 2. (4) The power transmission shaft according to claim 1 or 2, wherein the outer cylinder is joined to the flange portion of the inner shaft by welding.