JP5796841B2 - Power transmission device and method of manufacturing rolling element for power transmission device - Google Patents

Description

The present invention has a kinematic coupling device, and a method of manufacturing a rolling element for a power transmission device.
More particularly, the present invention provides a power transmission apparatus having an excellent rolling resistance to seizure property, and a method of manufacturing a rolling element for a power transmission device.

  Conventionally, in rolling elements for toroidal continuously variable transmissions used under high surface pressure, machine structural steel is further subjected to plasma high-concentration carburizing treatment or plasma high-concentration carburizing treatment to improve durability. What was made to do is proposed (refer patent document 1).

JP-A-8-338493

  By the way, for example, a multi-stage transmission using a traction drive or a transfer of a four-wheel drive vehicle has a structure in which the rolling element has a clutch mechanism. Little research is known.

  Therefore, when the present inventors used the rolling element described in Patent Document 1 as a rolling element that is used under a condition involving slipping, heat is generated due to, for example, slip that occurs during gear shifting or driving force transmission. We found a new problem that the amount increases and seizure occurs.

The present invention has been made to solve such a new problem.
Then, it is an object of the present invention, a power transmission apparatus having an excellent rolling resistance to seizure property, and to provide a method for manufacturing a rolling element for a power transmission device.

The inventors of the present invention have made extensive studies in order to achieve the above object.
As a result, a film containing hard particles having a hardness higher than the hardness of the substrate and a melting point higher than the melting point of the substrate and a metal material such as a single metal or an alloy as surface components was formed on the surface of the substrate . It has been found that the above object can be achieved by, for example, a configuration including a predetermined input shaft and output shaft made of rolling elements , and the present invention has been completed.

That is, the power transmission device of the present invention are those having an input shaft and an output shaft composed of rolling elements and a predetermined film formed on the surface of the substrate and the substrate.
And the said input shaft and the said output shaft have a contact surface in which the said predetermined membrane | film | coat which mutually contacts and transmits motive power was formed.
Further, the predetermined film has at least a surface configuration of at least one kind of hard particles having a hardness higher than the hardness of the base material and a melting point higher than the melting point of the base material, and a metal material composed of at least one of a single metal and an alloy. It is included as an element.

The method for manufacturing a rolling element for a power transmission device according to the present invention is a method for manufacturing a rolling element used in the power transmission device according to the present invention, wherein the formation of a film on the surface of a substrate is performed in a predetermined manner. This is a method performed by a thermal spraying method using a thermal spray material.
And the predetermined thermal spray material in this rolling element manufacturing method comprises at least one of at least one kind of hard particles having a hardness higher than the hardness of the base material and a melting point higher than the melting point of the base material, a single metal, and an alloy. Metal material.

According to the present invention, a power transmission apparatus having an excellent rolling resistance to seizure property, and it is possible to provide a manufacturing method of the rolling element of the power transmission device.

It is the schematic which shows an example of the structure of the film | membrane in the rolling element which concerns on one Embodiment of this invention. It is sectional drawing which shows an example of the power transmission device which concerns on one Embodiment of this invention. It is a perspective explanatory view showing the point of a seizure test. It is a graph which shows the load conditions in a seizure test. 2 is a graph showing the results of X-ray diffraction analysis of a film in Example 1. FIG.

Hereinafter, the dynamic force transmission device of the present invention, and will be described in detail a manufacturing method of the rolling element for power transmission device.

First, a rolling element according to an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram illustrating an example of a structure of a film in the rolling element of the present embodiment.
FIG. 1A is a schematic view of the structure of the film observed from the surface, and FIG. 1B is a schematic view of the structure of the film observed from a cross section.
As shown in FIG. 1, the rolling element 1 of the present embodiment includes a base material 2 and a predetermined film 4 formed on the surface of the base material 2.
The predetermined film 4 on the rolling element 1 is made of at least one kind of hard particles 4a having a hardness higher than the hardness of the base material 2 and a melting point higher than the melting point of the base material 2, and at least one of a single metal and an alloy. The metal material 4b is included as a surface constituent element.
In the present invention, “hardness” can be defined by, for example, Vickers hardness (HV), but is not limited to this, and other scales may be used.
In the present invention, the “surface constituent element” is an element that constitutes the surface when the structure of the film is observed from the surface. For example, in the rolling element shown in FIG. The particles 4a and the metal material 4b correspond.

  With such a configuration, the rolling element is excellent in seizure resistance. Therefore, power such as a multi-stage transmission using a traction drive or a transfer of a four-wheel drive vehicle having a structure in which the clutch mechanism is provided to the rolling element. It is suitable for use in a transmission device.

In the rolling element, the hardness of the coating is preferably higher than the hardness of the base material.
Thus, by making the hardness of the film itself higher than the hardness of the base material, the surface hardness becomes higher than the surface hardness of the conventional rolling element, so that the rolling element is more excellent in seizure resistance.

  Hereinafter, each configuration will be described in more detail.

(Substrate 2)
As the base material 2, what is used as the base material of the conventional rolling element can be applied.
As such a base material, for example, JIS G4051 carbon steel material for machine structure (SC) standardized by Japanese Industrial Standard (JIS), JIS G4052 structural steel material (H steel) guaranteed for quenching, JIS G4053 for structural use Alloy steel (manganese steel (SMn), manganese chromium steel (SMnC), chromium steel (SCr), chromium molybdenum steel (SCM), nickel chromium steel (SNC), nickel chromium molybdenum steel (SNCM)), JIS G4401 carbon tool steel Examples include steel (SK), JIS G4403 high speed steel (SKH), JIS G4404 alloy tool steel (SKS, SKD, SKT), JIS G4805 high carbon chromium bearing steel (SUJ), etc. it can.
These typically have a hardness of about 700 to 800 HV and a melting point of about 1400 to 1500 ° C.

(Hard particles 4a)
The hard particles 4a are not particularly limited as long as they have a relatively high hardness and a high melting point compared to the above-described base material.
Examples of such hard particles include carbide, boride, nitride, silicide, sulfide, oxide, and carbon hard particles.
In general, many of the hard particles described above exhibit high hardness and high melting point.
In addition, these may be contained alone or in combination of two or more.

Examples of hard carbide particles include titanium carbide (TiC), zirconium carbide (ZrC), vanadium carbide (VC), niobium carbide (NbC), tantalum carbide (TaC), chromium carbide (Cr ₃ C ₂ ), molybdenum carbide ( Examples thereof include hard particles composed of Mo ₂ C), tungsten carbide (WC), boron carbide (B ₄ C), silicon carbide (SiC), and the like.
Examples of the boride hard particles include titanium boride (TiB ₂ ), zirconium boride (ZrB ₂ ), vanadium boride (VB ₂ ), niobium boride (NbB ₂ ), tantalum boride (TaB ₂ ), boron Made of chromium bromide (CrB ₂ ), molybdenum boride (Mo ₂ B ₅ ), tungsten boride (W ₂ B ₅ ), boron (B), aluminum boride (AlB ₁₂ ), silicon boride (SiB ₆ ), etc. Hard particles can be mentioned.
Examples of the hard particles of nitride include titanium nitride (TiN), zirconium nitride (ZrN), vanadium nitride (VN), niobium nitride (NbN), chromium nitride (CrN), boron nitride (c-BN), silicon nitride ( Examples thereof include hard particles made of Si ₃ N ₄ ), aluminum nitride (AlN), or the like.
Examples of the oxide hard particles include aluminum oxide (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ), titanium oxide (TiO ₂ ), thorium oxide (ThO ₂ ), beryllium oxide (BeO), and magnesium oxide (MgO). Hard particles made of In addition, it is preferable that magnesium oxide is contained as magnesium zirconate, for example.
Examples of hard carbon particles include hard particles such as diamond (C).

Among these, tungsten carbide having a high hardness, a high melting point, and a high density (WC, Vickers hardness: 2350 HV, melting point: 2776 ° C., density: 15.72 g / cm ³ ) is particularly preferable.
Since tungsten carbide has a high density, there is an advantage that it is easy to form a dense film with few vacancies when the film is formed by a thermal spraying method to be described later.

(Metal material 4b)
Examples of the metal material 4b include, but are not limited to, a simple metal and an alloy. For example, an intermetallic compound or a solid solution may be used.
These may be used alone or in combination of two or more.
Examples of such a simple metal include cobalt (Co), iron (Fe), nickel (Ni), chromium (Cr), and titanium (Ti).
Examples of such alloys include cobalt (Co) -chromium (Cr), nickel (Ni) -chromium (Cr), hastelloy, chromium (Cr) -molybdenum (Mo), tungsten (W)- Chromium (Cr), nickel (Ni) -cobalt (Co) -chromium (Cr), tungsten (W) -cobalt (Co), nickel (Ni) -chromium (Cr) -aluminum (Al), nickel (Ni)- Molybdenum (Mo) etc. can be mentioned.
Among these, cobalt (Co) can be preferably used.
Since cobalt (Co) is easily plastically deformed, it is easy to form a dense film.

Examples of other elements constituting the coating include η phase when tungsten carbide is used as the hard particles when the coating is formed by a thermal spraying method to be described later.
The η phase is sometimes referred to as a lower carbide.
When tungsten carbide is applied as hard particles, which are constituents of the thermal spray material, when a coating is formed by a thermal spraying method, which will be described later, the component of tungsten carbide is applied to a single metal or alloy as a metal material, which is another constituent of the thermal spray material. Elutes.
At this time, when cobalt (Co) is applied as the metal material, for example, a η phase made of double carbide such as W ₃ Co ₃ C in addition to tungsten carbide (WC, W ₂ C) is formed.
The η phase generally has higher hardness and melting point than a single metal or alloy.
Therefore, by including the η phase, a rolling element with better seizure resistance is obtained.

Next, the manufacturing method of the rolling element which concerns on one Embodiment of this invention is demonstrated in detail.
The manufacturing method of the rolling element of this embodiment is an example of the manufacturing method of the rolling element which concerns on one Embodiment of this invention mentioned above.
Specifically, in producing a rolling element, the formation of a film on the surface of the substrate is performed by using at least one hard particle having a hardness higher than the hardness of the substrate and a melting point higher than the melting point of the substrate, a single metal, and This is performed by a thermal spraying method using a thermal spray material including a metal material made of at least one of alloys.
By using such a manufacturing method, a spray material having a particle size of several μm to several tens of μm can be sprayed on the surface of the base material, so that a film can be formed at a high film forming rate only on a necessary portion. .
Also, with such a production method, the content ratio of the hard particles in the thermal spray material can be set high, and a film can be formed only on a necessary portion, so that the rolling elements can be produced at low cost. There is also an advantage of being able to.

The thermal spraying method is preferably, for example, a thermal spraying method performed in the atmosphere.
If a film can be formed in the atmosphere, it can be easily applied to the production of large rolling elements.
Needless to say, the process can be performed under controlled atmosphere conditions.

Furthermore, the thermal spraying method is preferably, for example, a high-speed flame spraying method.
When a coating is formed by high-speed flame spraying, it is easy to elute the components of hard particles in the sprayed material into a single metal or alloy.
As a result, it becomes easy to form the η phase in the film, the hardness and melting point of the film are improved, and a rolling element with better seizure resistance can be obtained.

Moreover, it is preferable that the thermal spraying material in a thermal spraying method is a thermal spraying material granulated, for example using the hard particle | grains mentioned above and the particle | grains containing the metal material mentioned above.
When a thermal spray material granulated from hard particles and metal material particles is used, the composition of the thermal spray material has a high degree of freedom, and any combination of components is possible if fine primary particles are obtained.

Next, a power transmission device according to an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 2 is a sectional view showing a transfer of a four-wheel drive vehicle which is an example of a power transmission device according to an embodiment of the present invention.
In a transfer 100 of a four-wheel drive vehicle that is an example of a power transmission device, an input shaft 10 and an output shaft 20 that are examples of rolling elements are disposed in a housing H.
The input shaft 10 is rotatably supported with respect to the housing H by ball bearings 31 and 32, and the output shaft 20 is also rotatably supported with respect to the housing H by ball bearings 33 and 34.
The input shaft 10 is further rotatably supported with respect to the housing H by roller bearings 35 and 36 disposed in the housing H, and the output shaft 20 is further provided with roller bearings 37 and 38 disposed in the housing H. Also supported by the housing H so as to be rotatable.

Therefore, the roller bearings 35 and 37 positioned in the same axis perpendicular plane of the input / output shafts 10 and 20 are held in a common bearing support 39, and the bearing support 39 is housed by any means such as a bolt 40. Attach to the corresponding inside surface of H.
Further, the roller bearings 36 and 38 positioned in the same axis perpendicular plane of the input / output shafts 10 and 20 are held in a common bearing support 41, and the bearing support 41 is mounted on the housing H by any means such as a bolt 42. Attach to the corresponding inside surface.

Both ends of the input shaft 10 protrude from the housing H, the left end of the input shaft 10 in the drawing is coupled to the output shaft of the transmission (not shown), and the right end in the drawing is the rear propeller shaft (not shown). ) To the rear final drive unit (not shown).
The left end in the figure of the output shaft 20 is protruded from the housing H, and the protruding left end of the output shaft 20 is coupled to a front final drive unit (not shown) via a front propeller shaft (not shown).

The input shaft 10 is formed of bearing steel (SUJ), and has a first roller 11 formed of bearing steel (SUJ) in the middle in the axial direction thereof. A WC-Co film 12 is formed.
The output shaft 20 is also formed of bearing steel (SUJ), and has a second roller 21 formed of bearing steel (SUJ) in the middle in the axial direction, and has a high-speed flame spraying method on the surface thereof. Thus, the WC-Co film 22 is formed.
In these, the first roller 11 and the second roller 21 are arranged in a common axis perpendicular plane.
Then, the first roller 11 and the second roller 21 are pressed against each other in the radial direction, and the coatings on the outer peripheral surface of the roller are pressed and contacted with each other under preload at the locations indicated by reference numerals 12a and 22a.

That is, the bearing supports 39 and 41 are configured so that the distance between the axes of the first roller 11 and the second roller 21 is smaller than the sum of the radius of the first roller 11 and the radius of the second roller 21. A radial pressing force is generated between the roller 11 and the second roller 21.
The torque that can be transmitted between the first roller 11 and the second roller 21 is determined by the radial pressing force.
In FIG. 2, the coatings 12 and 22 are formed on both the first roller 11 and the second roller 21. However, if seizure resistance is satisfactory, the coating may be formed on only one of them. Good (not shown).

In the transfer 100, for example, when the rear wheel is on a slippery road surface and the front wheel is on a slippery road surface, the input shaft 10 rotates and the output shaft 20 does not rotate.
At that time, driving force is transmitted to the output shaft 20 by pressing the first rotor 11 of the input shaft 10 and the second rotor 21 of the output shaft 20 in order to drive the vehicle.
At that time, since the output shaft 20 is not rotated, the driving force is transmitted with a large sliding speed when pressed.
In the transfer to which the power transmission device of the present invention is applied, the predetermined film is formed, so that the occurrence of seizure can be suppressed or prevented and the driving force can be transmitted sufficiently.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these Examples.

(Examples 1 to 13, Comparative Examples 1 to 5)
The surface of each substrate shown in Table 1 was blasted using aluminum oxide particles.
Next, high-speed flame spraying under the conditions shown in Table 2 was performed using the thermal spray material obtained by granulation using the hard particles and metal material particles shown in Table 1, and the hard particles and metal materials shown in Table 1 were used. Was formed on the surface of the substrate to obtain rolling elements (blocks and rings) of Examples 1 to 13.
In addition, about the comparative example 1-the comparative example 5, the base material itself which has not formed the membrane | film | coat was made into the rolling element (block and ring) of the comparative example 1- comparative example 5. FIG.
The composition of the thermal spray material in Example 1 is WC-12 mass% Co.

[Performance evaluation]
(Seizure test)
A seizure test using a block-on-ring friction and wear tester (FFWEX, LFW-1) was performed.
First, rolling elements for seizure test (blocks and rings for seizure test) of each example were produced.
Specifically, the coating surfaces of the rolling elements (blocks and rings) of Examples 1 to 13 were ground using a diamond wheel, and then lapped using diamond abrasive grains. Thirteen rolling elements for seizure test (block and ring for seizure test) were obtained.
At this time, the seizure test block had a shape of 6.35 × 15.75 × 10.16 mm (according to ASTM test method), a film thickness of 120 μm, and a surface roughness of Ra 0.03 μm.
The seizure test ring had a shape of φ34.99 mm (according to the ASTM test method), the film thickness was 300 μm, and the surface roughness was Ra 0.03 μm.
On the other hand, the surfaces of the rolling elements (blocks and rings) of Comparative Examples 1 to 5 were ground using a diamond wheel, and then lapped using diamond abrasive grains, and seizures of Comparative Examples 1 to 5 were performed. A rolling element for test (a seizure test block and a ring) was obtained.
At this time, the seizure test block had a shape of 6.35 × 15.75 × 10.16 mm (according to ASTM test method) and a surface roughness of Ra 0.03 μm.
The seizure test ring had a shape of φ34.99 mm (according to ASTM test method) and a surface roughness of Ra 0.03 μm.

Next, the rolling elements for the seizure test of each example were attached to a block-on-ring frictional wear tester and arranged as shown in FIG. 3, and the seizure test was performed under the conditions shown in Table 3.
The obtained results are also shown in Table 1.

As shown in Table 1, in the rolling elements of Comparative Examples 1 to 5 outside the present invention, seizure occurred with a load of 250 lbs to 400 lbs, but Examples 1 to 13 belonging to the scope of the present invention. In the rolling element, no seizure occurred even at a load of 500 lbs.
From this, it can be seen that the power transmission device of the present invention has excellent seizure resistance.

Moreover, when the cross-sectional hardness of the rolling element for seizure test (block and ring for seizure test) of Example 1 was measured after the seizure test, the hardness of the substrate (SUJ2) was 700 HV to 750 HV, and the hardness of the film Was about 1100 HV.
Thus, since the hardness of the film itself is higher than the hardness of the base material, it is considered that the seizure resistance is excellent.

As can be seen from Examples 1 to 13 belonging to the scope of the present invention, it can be seen that WC, Cr ₃ C _{2 and the} like can be used alone or in combination as the hard particles.
Thus, it is considered that the seizure resistance is excellent because the carbide is applied.
However, the hard particles are not limited to these as long as they are hard particles having a higher hardness and a higher melting point than the base material, and those described above can be applied.
This can be inferred from the configuration of the present invention.

The result of X-ray diffraction analysis of this film is shown in FIG.
FIG. 5 shows that tungsten carbide (WC, W ₂ C) and η phase (Co ₃ W ₃ C) are present in the coating components by heating the WC-Co particles by the high-speed flame spraying method.
Moreover, it is considered that the seizure resistance is excellent because the η phase is contained together with tungsten carbide.

As explained in the rolling element manufacturing method of Examples 1 to 13 belonging to the scope of the present invention, a thermal spray material having a particle size of several μm to several tens of μm can be sprayed on the surface of the base material. A film can be formed only at a portion at a high film formation rate.
In addition, as described in the rolling element manufacturing method of Examples 1 to 13 belonging to the scope of the present invention, when a film can be formed in the atmosphere by a thermal spraying method, it is possible to manufacture a large rolling element. Also, it can be easily applied.
Further, as described in the rolling element manufacturing method of Examples 1 to 13 belonging to the scope of the present invention, when the coating is formed by high-speed flame spraying, the components of the hard particles in the sprayed material are converted to simple metals or alloys. It is easy to elute in, and it becomes easy to form the η phase in the film.
As a result, the hardness and melting point of the film are improved, and a rolling element with better seizure resistance can be obtained.
Furthermore, as explained in the rolling element manufacturing method of Examples 1 to 13 belonging to the scope of the present invention, when using a sprayed material granulated from hard particles and metal material particles, High degree of freedom in composition.
If fine primary particles are obtained, any combination of components becomes possible.

As mentioned above, although this invention was demonstrated with some embodiment and an Example, this invention is not limited to these, A various deformation | transformation is possible within the range of the summary of this invention.
For example, the present invention can also be applied to traction rollers, rolling rollers, guide rollers, roller bearings, and the like.

DESCRIPTION OF SYMBOLS 1 Rolling body 2 Base material 4 Film | membrane 4a Hard particle 4b Metal material 10 Input shaft 11 1st roller 12, 22 Film 20 Output shaft 21 2nd roller 31, 32, 33, 34 Ball bearing 35, 36, 37, 38 Roller bearing 39, 41 Bearing support 40, 42 Bolt 100 Transfer of four-wheel drive vehicle H housing

Claims (9)

A power transmission device provided with an input shaft and an output shaft made of rolling elements provided with a base material and a film formed on the surface of the base material ,
The input shaft and the output shaft have a contact surface on which the film is formed to contact each other and transmit power,
The coating includes at least one kind of hard particles having a hardness higher than the hardness of the substrate and a melting point higher than the melting point of the substrate, and a metal material composed of at least one of a metal simple substance and an alloy as surface constituent elements. A power transmission device characterized by the above. The power transmission device according to claim 1, wherein the coating has a hardness higher than a hardness of the base material. 3. The hard particle according to claim 1, wherein the hard particle is at least one hard particle selected from the group consisting of carbide, boride, nitride, silicide, sulfide, oxide, and carbon. Power transmission device. The power transmission device according to any one of claims 1 to 3, wherein the hard particles are hard particles made of tungsten carbide. The power transmission device according to claim 4, wherein the coating includes an η phase. It is a manufacturing method of a rolling element used for a power transmission device given in any 1 paragraph of Claims 1-5,
The formation of a film on the surface of the base material is made of at least one kind of hard particles having a hardness higher than the hardness of the base material and a melting point higher than the melting point of the base material, and a metal material composed of at least one of a single metal and an alloy. The manufacturing method of the rolling element for power transmission devices characterized by performing by the thermal spraying method using the thermal spraying material containing. The method for manufacturing a rolling element for a power transmission device according to claim 6 , wherein the thermal spraying method is a thermal spraying method performed in the atmosphere. The method for manufacturing a rolling element for a power transmission device according to claim 6 or 7 , wherein the thermal spraying method is a high-speed flame spraying method. The power spray device according to any one of claims 6 to 8, wherein the thermal spray material is a thermal spray material granulated using the hard particles and particles containing the metal material . A method for manufacturing a rolling element.

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