JP2015168806A - Method for producing grease for pivot, method for producing pivot, and pivot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing grease for a pivot in which torque is low, and the generation of outgas is inexpensively reduced while maintaining its lubricity performance over a long period by its high durability by low torque variation.SOLUTION: The method for producing grease for a pivot comprises: a blending step S1 of blending components composing grease to produce a mixture; and a volatilization step S2 of leaving a mixture simple substance produced in the blending step S1 for a prescribed time in an atmosphere whose temperature is adjusted to a temperature higher than ordinary temperature.

Description

  The present invention relates to a method for manufacturing a grease for a pivot, a method for manufacturing a pivot, and a pivot.

  2. Description of the Related Art Conventionally, a bearing using grease in which a high viscosity base oil and a thickener made of a specific urea compound are blended is known (see, for example, Patent Documents 1 and 2).

JP 2007-112998 A JP 2008-115991 A

  However, in the greases used in the bearings of Patent Documents 1 and 2, it is difficult to manage the compounding ratio of components for reducing the generation of outgas, and such grease has a disadvantage that it is relatively expensive.

  The present invention has been made in view of the circumstances described above, and is for a pivot that can reduce outgas generation at low cost while maintaining lubrication performance over a long period of time with low torque and high durability due to low torque fluctuations. It is an object of the present invention to provide a grease manufacturing method, a pivot manufacturing method, and a pivot.

In order to achieve the above object, the present invention provides the following means.
In one aspect of the present invention, a blending step of blending components constituting the grease to form a mixture, and the mixture alone generated in the blending step is placed in an atmosphere adjusted to a temperature higher than normal temperature over a predetermined time. A method for producing a grease for a pivot including a volatilizing step to be left is provided.

  According to this aspect, the simple substance mixture of the components constituting the grease such as the urea compound and the thickener blended in the blending step is left in the high-temperature atmosphere in the volatilization step, thereby being contained in the mixture. The component that generates outgas is volatilized, and the component that generates outgas can be released before being sealed in the bearing. By releasing the component that generates outgas from the mixture, it is possible to produce a grease with a sufficiently reduced concentration of the component that generates outgas when encapsulated in the bearing.

  In this case, unlike the conventional method of reducing the component that generates outgas by adjusting the compounding ratio of the component, the component that generates outgas is released in the volatilization step after the compounding step, so that outgas is generated during compounding. Even if many components are contained, the concentration of the components that generate outgas in the final grease can be reduced. That is, in the blending step, the blending ratio for improving the lubrication performance such as low torque and low torque fluctuation can be freely selected, and a low-cost grease with high lubrication performance can be manufactured.

  Another aspect of the present invention provides a method of producing a grease for a pivot including a volatilization step in which a mixture containing a component constituting the grease is allowed to stand for a predetermined time in an atmosphere adjusted to a temperature higher than room temperature.

  According to this aspect, the component that generates outgas is released from the mixture containing the component that constitutes the grease in the volatilization step, so that the concentration of the component that generates outgas is sufficiently reduced when sealed in the bearing. Grease can be manufactured. In addition, a mixture having high lubrication performance such as low torque and low torque fluctuation can be freely selected as the mixture alone, and a low-cost grease having high lubrication performance can be produced.

In the said aspect, the said volatilization process may arrange | position the said mixture in the low pressure atmosphere lower than atmospheric pressure.
By doing so, since the boiling point of the component that generates outgas contained in the mixture is lowered, the temperature for releasing the component that generates outgas can be lowered, and volatilization of the component can be further promoted. .

In the above aspect, the volatilization step may be performed a plurality of times with a time interval, and may include a stirring step of stirring the mixture between the volatilization steps.
By doing in this way, in each volatilization process, the component that generates outgas near the surface of the mixture is volatilized, and the component that generates outgas positioned near the surface of the mixture decreases, but until the next volatilization process In the stirring step, the surface of the mixture in contact with the surrounding atmosphere is replaced. This makes it possible to more efficiently release components that generate outgas in the next volatilization step, reduce unevenness in the concentration of components that generate outgas contained in the mixture, and manufacture a homogeneous grease.

In the said aspect, the surface area expansion process which expands the surface area of the said mixture may be included before the said volatilization process.
By doing in this way, the discharge | release amount of the component which generate | occur | produces the outgas which volatilizes from the surface of a mixture per unit time can be increased, and it can volatilize more efficiently.

  Another aspect of the present invention is a bearing assembly step in which the inner ring and the outer ring are arranged coaxially, and the rolling elements are arranged in the annular space between the inner ring and the outer ring with a circumferential interval therebetween, and the above method. There is provided a pivot manufacturing method including an injection step of injecting the manufactured pivot grease into the annular space, and a fitting step of fitting a shaft to the inner ring of the bearing after the injection step.

  According to this aspect, a pivot with reduced outgas generation during use can be manufactured by assembling the pivot by injecting grease manufactured by volatilizing components that generate outgas in advance into the bearing.

  Another aspect of the present invention is manufactured by the above-described method, and inner and outer rings arranged coaxially, a plurality of rolling elements arranged in the annular space between the inner ring and the outer ring at circumferential intervals. A pivot comprising a bearing having a grease for pivot injected into the annular space and a shaft fitted to the inner ring of the bearing is provided.

  According to the present invention, it is possible to reduce generation of outgas at low cost while maintaining lubrication performance over a long period of time with low torque and high durability due to low torque fluctuation.

It is the longitudinal cross-sectional view which fractured | ruptured a part of pivot which concerns on one Embodiment of this invention to the axial direction. It is a flowchart which shows the manufacturing method of the grease for pivots used for the pivot of FIG. It is a flowchart which shows the manufacturing method of the pivot of FIG. 6 is a flowchart showing a modification of the method for manufacturing the pivot grease of FIG. 2. It is a perspective view which shows an example of the surface area expansion process in the manufacturing method of the grease for pivots of FIG.

A manufacturing method of pivot grease (hereinafter simply referred to as grease), a manufacturing method of a pivot, and a pivot according to an embodiment of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the pivot 1 according to the present embodiment includes two bearings 2, a shaft 3 fitted to the bearings 2, and a spacer member 4 sandwiched between the two bearings 2 in the axial direction. It has.

  As shown in FIG. 1, the two bearings 2 are arranged adjacent to each other in the radial direction and are coaxially arranged in an annular inner ring 5 and an outer ring 6, and an annular space 7 between the inner ring 5 and the outer ring 6. And a plurality of rolling elements 8 arranged at intervals in the circumferential direction. The annular space 7 is filled with grease 9 as a lubricant.

  The inner ring 5 has a raceway (inner ring raceway) formed on the outer peripheral surface, and the outer ring 6 has a raceway (outer ring raceway) formed on the inner peripheral surface. By rolling the rolling elements 8 between the raceway of the inner ring 5 and the raceway of the outer ring 6, the inner ring 5 and the outer ring 6 are rotated relative to each other.

The rolling elements 8 are rotatably held in the annular space 7 in a state of being arranged at equal intervals by a retainer (not shown).
The retainer is formed in a concave shape by connecting a plurality of projections provided in the axial direction along the circumferential direction of the annular base portion, connecting the projections, and a rolling element 8. And a grease pocket for holding the grease 9 therebetween.

  The grease 9 includes a viscous base oil (for example, mineral oil, ester-based synthetic oil, synthetic hydrocarbon oil (poly α-olefin), etc.) and a urea compound (for example, an aliphatic urea compound, an alicyclic urea compound, And a thickener comprising an aromatic urea compound. The grease 9 adheres to the raceway of the inner ring 5, the raceway of the outer ring 6, and the surfaces of the rolling elements 8, so that the pivot 1 maintains good torque characteristics and fluidity. Further, the content of the thickener in the grease 9 is preferably 10 to 20% by mass.

  The spacer member 4 is formed in a hollow ring shape, the inner diameter dimension is larger than the outer diameter dimension of the inner ring 5, and the outer diameter dimension is approximately the same as the outer diameter dimension of the outer ring 6. . The spacer member 4 is sandwiched between the outer rings 6 of the two bearings 2 in the axial direction. Thereby, a gap is formed between the inner rings 5 of the two bearings 2.

The shaft 3 is formed in a hollow, substantially cylindrical shape, and is provided with a flange-like flange portion 10 that extends radially outward over the entire circumference at one end.
In a state where the spacer member 4 is sandwiched between the outer rings 6 and the shaft 3 is fitted in the inner ring 5, a preload is applied to the two bearings 2 by applying an external force that brings the inner rings 5 close to each other in the axial direction. The pivot 1 can be manufactured.

Next, the manufacturing method of the grease 9 according to this embodiment will be described below.
As shown in FIG. 2, the manufacturing method of the grease 9 according to this embodiment includes a blending step S1 for blending components constituting the grease 9 such as a base oil and a thickener to generate a mixture P, and a mixture P. 2 includes a volatilization step S2 for volatilizing a component that generates outgas (hereinafter referred to as an outgas component) contained in and a stirring step S4 for stirring the mixture P.

In the blending step S1, the mixture P is generated by selecting and mixing the components necessary to achieve the desired lubrication performance.
In the volatilization step S2, the mixture P alone generated in the blending step S1 is placed in a container opened at least partially or placed on a plate and placed in a temperature-controlled room where the internal temperature and pressure can be adjusted. Is done. The temperature-controlled room is set to a temperature higher than room temperature, for example, 60 to 120 ° C, preferably 80 ° C or higher. The temperature-controlled room is decompressed to a pressure lower than atmospheric pressure, for example, 5 Torr or less, preferably 1 Torr or less. Therefore, the mixture P is arrange | positioned in a high temperature reduced pressure atmosphere. The volatilization step S2 is performed by leaving the mixture P in such a high-temperature and reduced-pressure atmosphere for a predetermined time (for example, 1 hour). The normal temperature refers to, for example, 15 degrees Celsius.

After the volatilization step S2 is completed, it is determined whether or not the volatilization step S2 has been performed a preset number of times (step S3). If the preset number of times has not been reached, the stirring step S4 has been performed. Later, the volatilization step S2 is performed again.
The stirring step S4 is a step of taking out and stirring the mixture P after the volatilization step S2 from the temperature-controlled room. The surface exposed around the mixture P is replaced by the stirring step S4.

  According to the manufacturing method of the grease 9 according to the present embodiment, in the volatilization step S2, the atmosphere in which the mixture P is placed is brought into a high temperature and reduced pressure state, so that the boiling point of the outgas component contained in the mixture P is lowered, and the outgas component Can be easily volatilized from the surface of the mixture P. Thereby, the outgas component which exists in the surface vicinity of the mixture P can be efficiently discharge | released to circumference | surroundings.

  Further, since the volatilization step S2 is performed a plurality of times and the agitation step S4 is performed during the volatilization step S2, the vicinity of the surface where the concentration of the outgas component has decreased due to the release of the outgas component and the outgas component has not yet been released. The inside having a high concentration of the outgas component is mixed by stirring, and a portion having a high concentration of the outgas component is newly disposed near the surface. And in volatilization process S2 implemented after stirring, an outgas component can be volatilized from the high concentration part of the outgas component newly arrange | positioned in the surface vicinity, and discharge | release of an outgas component can be accelerated | stimulated.

  Thus, according to the manufacturing method of the grease 9 according to the present embodiment, the mixture P generated in the blending step S1 contains a large amount of outgas components by applying a blending ratio intended to improve lubrication performance and reduce costs. Even if it is, the grease 9 having a sufficiently reduced concentration of the outgas component can be finally produced through the volatilization step S2 and the stirring step S4. In other words, since the outgas component is removed after blending, the component to be blended can be freely selected from components having characteristics for improving lubricating performance such as low torque and low torque fluctuation, and its blending ratio. Thus, there is an advantage that the grease 9 having high lubricating performance can be manufactured.

  Moreover, according to the manufacturing method of the grease 9 which concerns on this embodiment, in the volatilization process S2, since the mixture P is arrange | positioned by itself in a constant temperature chamber, the state enclosed with the bearing 2 or the state which comprised the pivot 1 Compared with the case where it is arranged in a temperature-controlled room, there is also an advantage that the heat capacity can be reduced, and the energy used for releasing the outgas component can be reduced.

In the present embodiment, as shown in FIG. 4, a surface area expansion (application) step S5 for expanding the surface area of the mixture P may be performed prior to the volatilization step S2.
As the surface area expanding step S5, for example, as shown in FIG. 5, the mixture P generated in the blending step S1 or the mixture P stirred in the stirring step S4 is threaded (for example, a diameter of 1 mm or less from the nozzle of the dispenser 11). And the surface area of the mixture P can be increased by discharging it onto the plate 12.

Moreover, you may employ | adopt the method of enlarging the surface area of the mixture P by extending the mixture P discharged from the nozzle of the dispenser 11 thinly on the plate 12 using a spatula, a roller, etc., for example. The thickness dimension of the thinly stretched mixture P is preferably 1 mm or less, and more preferably 0.3 mm or less.
By performing surface area expansion process S5, an outgas component can be volatilized efficiently from the surface where mixture P was expanded.

Moreover, in the manufacturing method of the grease 9 according to the present embodiment, the mixture P placed in the constant temperature room in the high temperature and reduced pressure atmosphere in the volatilization step S2 was taken out from the constant temperature room, and the stirring step S4 was performed at room temperature and normal pressure. Instead of this, the stirring device may be placed in a temperature-controlled room, and the stirring step S4 may be performed in the same high temperature and reduced pressure atmosphere as the volatilization step S2. As the stirring device, any device such as a revolving rotation type and a blade type can be adopted.
By doing in this way, the heat_generation | fever by friction of the mixture P at the time of stirring can also be utilized as energy for making the mixture P high temperature.

In the present embodiment, the case where the blending step S1, the volatilization step S2, and the stirring step S4 are all manually performed is described as an example. However, these steps may be automatically performed.
In the present embodiment, as a method for producing the grease 9, the case where the blending step S1 for generating the mixture P and the volatilization step S2 are performed has been described as an example. However, the present invention does not include the blending step S1, This may be applied to the case where the volatilization step S2 is performed using a ready-made grease product as the mixture P.

Next, the pivot 1 and the manufacturing method thereof according to an embodiment of the present invention will be described.
As shown in FIG. 3, the manufacturing method of the pivot 1 according to the present embodiment is assembled with the grease manufacturing step T1 for manufacturing the grease 9 and the bearing assembly step T2 for assembling the two bearings 2 by the above method. An injection step T3 for injecting the grease 9 into the bearing 2 and a fitting step T4 for fitting the shaft 3 into the inner ring 5 of the bearing 2 into which the grease 9 has been injected are included.

In the bearing assembly step T2, the inner ring 5 of the bearing 2 and the outer ring 6 corresponding to the inner ring 5 are arranged coaxially, a retainer is arranged in the annular space 7 between the inner ring 5 and the outer ring 6, and The bearings 2 are assembled by arranging the rolling elements 8 at intervals in the direction.
In the injection step T3, the grease 9 manufactured in the grease manufacturing step T1 is injected into the grease pocket of the retainer provided in the annular space 7 of each bearing 2 assembled in the bearing assembly step T2.

  In the fitting step T4, the adhesive is applied to the inner surfaces of the inner rings 5 of the two bearings 2 into which the grease 9 has been injected, and the shaft 3 is moved to a position where one end surface of the one bearing 2 abuts against the flange portion 10. After the fitting, the other bearing 2 is fitted to the shaft 3 in a state where the spacer member 4 is disposed so as to be sandwiched between the outer rings 6. After that, the pivot 1 is manufactured by curing the adhesive in a state where an appropriate preload is applied by applying an external force in a direction in which the inner rings 5 of the two bearings 2 are close to each other.

  As described above, according to the method for manufacturing the pivot 1 according to the present embodiment, since the grease 9 in which the concentration of the outgas component is sufficiently reduced is injected, it is possible to manufacture the pivot 1 with reduced outgas generation during use. it can.

In this case, since the grease 9 in which the concentration of the outgas component is reduced in a single state is used, compared with the case where the outgas component is released in the high temperature atmosphere after the assembly of the pivot 1, the component due to the difference in thermal expansion coefficient is reduced. Generation of problems such as deformation, plastic deformation of the adhesive, and distortion due to creep can be prevented.
As a result, according to the pivot 1 according to the present embodiment, high bearing performance with low torque and low torque fluctuation can be exhibited.

Reference Signs List 1 pivot 2 bearing 3 shaft 5 inner ring 6 outer ring 7 annular space 8 rolling element 9 grease

Claims (7)

A blending step of blending the components that make up the grease to produce a mixture;
A pivoting grease manufacturing method comprising: a volatilization step in which the mixture alone generated in the blending step is left in an atmosphere adjusted to a temperature higher than normal temperature for a predetermined time.   A pivot grease manufacturing method including a volatilization step in which a mixture containing a component constituting a grease is allowed to stand for a predetermined time in an atmosphere adjusted to a temperature higher than room temperature.   The manufacturing method of the grease for pivots of Claim 1 or Claim 2 which arrange | positions the said mixture in the low pressure atmosphere lower than atmospheric pressure in the said volatilization process. The volatilization process is performed a plurality of times with a time interval,
The manufacturing method of the grease for pivots as described in any one of Claims 1-3 including the stirring process which stirs the said mixture between the said volatilization processes.   The manufacturing method of the grease for pivots as described in any one of Claims 1-4 including the surface area expansion process which expands the surface area of the said mixture before the said volatilization process. A bearing assembly step in which the inner ring and the outer ring are arranged coaxially, and the rolling elements are arranged in an annular space between the inner ring and the outer ring with a circumferential interval therebetween;
An injecting step of injecting the pivot grease produced by the method according to any one of claims 1 to 5 into the annular space;
And a fitting step of fitting a shaft to the inner ring of the bearing after the injection step. The inner ring and the outer ring that are arranged coaxially, and a plurality of rolling elements that are arranged in the annular space between the inner ring and the outer ring at intervals in the circumferential direction, and any one of claims 1 to 5. A bearing having pivot grease manufactured by the method described above and injected into the annular space;
A pivot comprising a shaft fitted to the inner ring of the bearing.

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