JP2001181668A - Lubricating grease and motor with speed-reducing mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lubricating grease capable of stably exhibiting its excellent lubricating characteristics even if used between sliding members subjected to high contact pressure. SOLUTION: This lubricating grease is obtained by adding >=10 wt.% of PE beads each 5-40 μm in diameter as solid lubricant to a base grease. The lubricating grease can exhibit its excellent lubricating characteristics even if used between sliding members (between a worm 4b and a worm wheel 10) subjected to mutual contact pressure exceeding 0.5 kgf/mm2 since the mutual coefficient of static friction is stably suppressed to low levels.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating grease and a motor with a speed reduction mechanism in which the grease is applied between a sliding member such as a worm and a worm wheel, or a rotating shaft and a bearing on which a high contact pressure acts.

[0002]

2. Description of the Related Art A vehicle is equipped with a motor having a speed reduction mechanism having a worm and a worm wheel as a drive source of a wiper device, a power window device and the like. Such a motor with a speed reduction mechanism is required to have a smaller size and a higher output than ever before, and further higher efficiency is desired. Therefore, as one method, it has been considered to improve the lubricating grease applied to the meshing portion between the worm and the worm wheel, reduce the frictional resistance between them, and increase the efficiency of the motor.

[0003]

By the way, specific examples of the lubricating grease are disclosed in JP-A-8-20787 and JP-A-4-20787.
Although it is disclosed in JP-A-63895, this publication discloses general techniques for reducing the sliding noise generated between the sliding contact portions and reducing mutual wear.

However, a motor used for a wiper device or a power window device may apply a large load to its output shaft. In such a case, a high contact pressure acts on the tooth surfaces of the worm and worm wheels. In the case where the lubricating grease is used between parts where such a high contact pressure acts, it is not described whether the lubricating grease is effective. Therefore, in some cases, not only the sliding resistance cannot be reduced and the efficiency of the motor cannot be improved, but also there is a possibility of causing a failure.

[0005] This is not limited to the meshing portion between the worm and the worm wheel, but also between the sliding contact surfaces between the bearing and the rotating shaft,
When the above-described lubricating grease is used between other sliding members other than the motor on which a high contact pressure acts, a similar problem may occur.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to stably provide excellent lubrication characteristics even when used between sliding parts where a high contact pressure acts. An object of the present invention is to provide a lubricating grease and a motor with a speed reduction mechanism that can be exerted.

[0007]

According to a first aspect of the present invention, a solid lubricant is added to a base grease, and the contact lubrication exceeds 0.5 [kgf / mm ² ]. A lubricating grease used between sliding contact members in which pressure acts on each other, wherein the solid lubricant has a particle size of 5 [μm] to 4 [μm].
0 [μm], and the solid lubricant was added in an amount of 10% by weight or more.

According to a second aspect of the present invention, there is provided the lubricating grease according to the first aspect, wherein the solid lubricant has a particle size of 10%.
[Μm] to 40 [μm]. According to a third aspect of the present invention, in the lubricating grease according to the first or second aspect, the solid lubricant is added in an amount of 15% by weight or more.

According to a fourth aspect of the present invention, in the lubricating grease according to the first aspect, the solid lubricant comprises at least polyethylene beads. The invention according to claim 5 is the lubricating grease according to claim 4, wherein the solid lubricant further comprises polytetrafluoroethylene powder.

According to a sixth aspect of the present invention, there is provided a motor with a speed reduction mechanism, wherein the lubricating grease according to any one of the first to fifth aspects is used for at least one of a gear meshing portion and a bearing portion.

Therefore, according to the first aspect of the present invention,
10 μm of solid lubricant having a particle size of 5 μm to 40 μm
[Weight%] At least, lubricating grease is added to base grease. 0.5 [kgf /
When it is used between the sliding contact members in which a contact pressure exceeding ² mm ² acts on each other, the coefficient of static friction between them can be stably reduced, and excellent lubrication performance can be exhibited (see FIGS. 3 to 8).

According to the second aspect of the present invention, since the particle size of the solid lubricant is set to 10 [μm] to 40 [μm], the coefficient of static friction between the sliding contact members can be reduced more stably, which is excellent. (See FIGS. 3 to 8).

According to the third aspect of the present invention, since the solid lubricant is added in an amount of 15% by weight or more, the coefficient of static friction between the sliding members can be reduced more stably, and excellent lubrication performance can be exhibited. (See FIGS. 3 to 8).

According to the fourth aspect of the invention, by adding at least polyethylene beads as a solid lubricant, the coefficient of static friction between them can be stably reduced, and excellent lubrication performance can be exhibited (FIGS. 3 to 3). See FIG. 8).

According to the fifth aspect of the present invention, by further adding polytetrafluoroethylene powder as a solid lubricant, the coefficient of static friction between them can be reduced more stably, and excellent lubrication performance can be exhibited. (See FIG. 5).

According to the invention of claim 6, according to claim 1,
The lubricating grease according to any one of the above items (5) to (5) is used for at least one of a gear mesh portion and a bearing portion of a motor with a speed reduction mechanism. Since this lubricating grease can stably reduce the coefficient of static friction between each other and exhibit excellent lubrication performance,
The efficiency of the motor can be improved.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a motor 1 with a speed reduction mechanism used in a power window device for a vehicle. The motor unit 2 as a drive source of the motor 1 with the reduction mechanism includes a yoke housing 3, a rotor 5 having a rotating shaft 4, a magnet 6, a brush device 7, and the like. Yoke housing 3
Is formed in a bottomed cylindrical shape, and a bearing recess 3a is formed in the bottom thereof. A metal bearing 8 is fixed to the bearing recess 3a,
The base end (the lower end in FIG. 1) of the rotating shaft 4 is rotatably supported by the bearing 8. The base end of the rotating shaft 4 is provided with a thrust sliding contact portion 4a, and the rotating shaft 4 is supported with the thrust sliding contact portion 4a in contact with the bottom surface of the bearing recess 3a. That is, the bearing recess 3 a is a bearing portion that receives a thrust load of the rotating shaft 4.

The opening 3b of the yoke housing 3 is provided with a resin-made deceleration housing 9 so as to cover the protruding rotary shaft 4.
Is assembled. The inside of the reduction housing 9 is formed in a predetermined shape capable of accommodating a part of the rotary shaft 4 disposed therein and the worm wheel 10 and the like. Reduction housing 9
Inside, two metal bearings 11 and 12 are fixed, and the center and the tip (the upper end in FIG. 1) of the rotating shaft 4 are rotatably supported by the bearings 11 and 12.

In the speed reduction housing 9, a bearing recess 9a is formed at the tip end face of the rotating shaft 4 with its opening facing the opening. A thrust plate 13 is fitted into the bearing recess 9 a, and a thrust receiving member 14 is interposed between the plate 13 and the end face of the rotating shaft 4. That is, the thrust plate 13 and the thrust receiving member 14 are
Of the bearing portion receiving the thrust load.

A worm 4b is formed between the bearings 11 and 12 of the rotary shaft 4. When the worm 4b and the worm wheel 10 mesh with each other, a rotational force is transmitted to an output shaft (not shown) provided in a direction orthogonal to the rotary shaft 4 to open and close the window glass. I have.

The worm 4b and the worm wheel 10
The lubricating grease G is applied to the meshing portion. As shown in FIG. 2, the lubricating grease G was prepared by mixing a base grease x obtained by mixing a base oil composed of polyalkylene glycol and a thickener composed of lithium soap with spherical polyethylene beads (PE) as a solid lubricant. (Beads) y is added. The motor 1 is further opened when a high contact pressure acts between the meshing portions, that is, between the mutual tooth surfaces of the worm 4b and the worm wheel 10, especially when the window glass is arranged at the upper end position or the lower end position. 3 [k] when trying to rotate in the
gf / mm ² ]. The lubricating grease G of the present embodiment smoothes the sliding between the parts on which such a high contact pressure acts.

Here, the present applicant has studied the composition of the lubricating grease G suitable between the worm 4b and the worm wheel 10 on which a high contact pressure acts as follows. In this embodiment, the worm 4b (rotating shaft 4) is made of iron (S55).
C), the worm wheel 10 is made of polyacetal resin (P
OM resin), but in order to simulate the meshing portion, various lubricating greases G1 to G6 described later are applied to the upper surface of a metal plate made of iron (S55C), and the lubricating greases G1 to G6 are formed on the lubricating greases G1 to G6. A resin plate made of polyacetal (POM) was arranged, and the resin plate was pressed against the metal plate with a predetermined pressure. Then, the measuring device having such a configuration was left in an atmosphere at 80 ° C. for 96 hours, and then the static friction coefficient between both plates was measured under the following various conditions 1 to 3.

1. The change of the static friction coefficient between the S55C plate and the POM plate with the increase of the contact pressure was measured. As shown in FIG. 3, PE beads were added to base grease (polyalkylene glycol + lithium soap) at 15% by weight.
Without adding lubricating grease G1 and PE beads,
That is, the change in the static friction coefficient when the PE beads used lubricating grease G2 of 0 [wt%] was measured. still,
In this case, the particle size of the PE beads was 20 [μm].
To both greases G1 and G2, 2% by weight of polytetrafluoroethylene powder (PTFE powder) as a solid lubricant having the same particle size as the PE beads is added. In this measurement, the mutual contact pressure between the S55C metal plate and the POM resin plate was set to 0.25.
It was increased from [kgf / mm ² ] to 4.5 [kgf / mm ² ].

According to the characteristic diagram of FIG. 3, the mutual contact pressure is 0.25 [kgf / mm ² ] to 1.5 [kgf / mm ² ].
In the section up to, the static friction coefficient when the lubricating grease G1 is used increases from about 0.07 to about 0.11, and the static friction coefficient when the lubricating grease G2 is used is about 0.08 to
Increase to about 0.17. That is, the degree of increase in the coefficient of static friction in the lubricating grease G1 is smaller than that in the lubricating grease G2.

In this case, the mutual contact pressure is relatively low, from 0.25 [kgf / mm ² ] to 0.5 [kgf / mm ² ].
In the section up to, the difference in the static friction coefficient between the two greases G1 and G2 is small, but the mutual contact pressure is 0.5 [kgf / m
m ^2] to 1.5 at [kgf / mm ^2] to sections of the static friction coefficient in the lubricating grease G2 is rapidly increased as compared with that in the lubricating grease G1, gradually increases the difference between the static friction coefficient in both grease G1, G2 Become.

The mutual contact pressure is 1.5 [kgf /
In the section from mm ² ] to 4.5 [kgf / mm ² ], the coefficient of static friction in the lubricating grease G1 is substantially constant at about 0.11, and the coefficient of static friction in the lubricating grease G2 is substantially constant at about 0.17. That is, in this section, both greases G
The static friction coefficients at 1 and G2 become almost constant without increasing.

Therefore, according to this characteristic diagram, the particle size is 20
Lubricating lubricated with 15 [% by weight] PE beads of [μm]
The squirrel G1 is 0.5 [kgf / mm^TwoContact pressure exceeding
Excellent lubrication characteristics when used between plates where
It turned out to show. Further, the lubricating grease G1 is 1.5
[Kgf / mm^TwoPlate on which a contact pressure exceeding
When used in between, the coefficient of static friction between the plates is almost constant
Therefore, it was found that stable lubrication characteristics were exhibited. One
In short, the lubricating grease G1 is 0.5 [kgf / mm ^Two]
It is preferable to use between plates where the contact pressure exceeds
Preferably, 1.5 [kgf / mm^TwoContact pressure exceeding
It is best to use between plates
You.

2. S55C with increasing particle size of PE beads
Measure the change in the coefficient of static friction between the plate and POM plate. As shown in FIG. 4, the particle size was 5 [μ] with respect to the base grease (polyalkylene glycol + lithium soap).
m] to 40 [μm], and the coefficient of static friction was measured when lubricating grease G3 to which 15% by weight of PE beads of each particle diameter was added was used (the particle diameter in FIG. Is the static friction coefficient of the lubricating grease G3 when no PE beads are added). still,
In this case, the mutual contact pressure between the S55C metal plate and the POM resin plate was kept constant at 1.8 [kgf / mm ² ].

According to the characteristic diagram of FIG. 4, in the section where the particle size of the PE beads is 0 [μm] to 5 [μm], the decrease in the static friction coefficient when the lubricating grease G3 is used is small,
In the section where the particle size of the E beads is 5 [μm] to 10 [μm], the static friction coefficient of the lubricating grease G3 is about 0.18.
It sharply decreases to about 0.13.

Then, the particle size of the PE beads is 10 [μm].
In the section from about 25 μm to about 25 μm, the coefficient of static friction in the lubricating grease G3 gradually decreases from about 0.13 to about 0.11, and the particle size of the PE beads is about 25 μm to 40 μm.
m], the static friction coefficient of the lubricating grease G3 gradually increases from about 0.11 to about 0.12. That is, the particle size of the PE beads is 10 [μm] to 40 [μm].
The section up to is a stable section where the static friction coefficient of the lubricating grease G3 is as small as about 0.13 to about 0.11, and the change is small. In addition, the particle size of the PE beads is 40 [μ
m], it is estimated that the coefficient of static friction increases as the particle size of the PE beads increases, though not shown. Further, in order to use such PE beads for the meshing portion between the worm 4b and the worm wheel 10, the size thereof is inappropriate.

Therefore, according to this characteristic diagram, 1.8 [k]
gf / mm ² ], when used between plates on which a contact pressure acts, lubricating grease G3 added with 15% by weight of PE beads having a particle size of 5 μm to 40 μm has excellent lubricating properties. It turned out to show. The particle size is 10 [μm]
It was found that lubricating grease G3 to which 15% by weight of PE beads of up to 40 [μm] was added exhibited a more stable lubricating characteristic because the coefficient of static friction between the plates was almost constant.

Further, according to the characteristic diagram shown in FIG. 3, in the section where the contact pressure is 0.5 [kgf / mm ² ] to 4.5 [kgf / mm ² ], PE having a particle size within the above range is obtained. It can be inferred that the lubricating grease G3 to which the beads are added has excellent lubricating properties.

As a result, the contact pressure becomes 0.5 [kgf / m
m ² ], the particle size of the PE beads added to the grease G3 is 5
[Μm] to 40 [μm] is preferable and 10 [μm]
m] to 40 [μm] can be estimated to be optimal.

3. S55 with increasing amount of PE beads added
Measure the change in the coefficient of static friction between the C plate and POM plate. As shown in FIG. 5, the base grease (polyalkylene glycol + lithium soap) has a particle size of 20%.
[Μm] of the PE beads is 0 [wt%] to 25 [% by weight].
Each lubricating grease G4-G6 increased to [% by weight]
The coefficient of static friction in the case of using was measured. In this case, the mutual contact pressure between the metal plate made of S55C and the resin plate made of POM was kept constant at 1.8 [kgf / mm ² ]. Further, the above-mentioned PTFE powder is not added to the lubricating grease G4. On the other hand, lubricating grease G5 has
PTFE powder was added at 2% by weight, and lubricating grease G6 was added at 4% by weight PTFE powder.

According to the characteristic diagram of FIG. 5, in the section where the amount of PE beads added is 0 [% by weight] to 15 [% by weight], the coefficient of static friction when lubricating grease G4 is used is about 0.18 to 0.1%.
The coefficient of static friction when using the lubricating grease G5 is reduced to about 0.17 to about 0.11, and the coefficient of static friction when using the lubricating grease G6 is reduced to about 0.16.
To about 0.10. In this case, the section in which the amount of the PE beads added is 10 [% by weight] to 15 [% by weight]
All of the greases G4 to G6 are sections in which the decrease width of the static friction coefficient is small.

In the section where the amount of the PE beads added is 15 [% by weight] to 25 [% by weight], the static friction coefficient of the lubricating grease G4 is substantially constant at about 0.12, and the static friction coefficient of the lubricating grease G5 is substantially constant. The coefficient of static friction in the lubricating grease G6 is substantially constant at about 0.10. That is, in this section, the coefficient of static friction in each of the greases G4 to G6 is substantially constant without any increase.

In other words, the section in which the amount of PE beads added is 10 [% by weight] to 25 [% by weight] corresponds to each lubricating grease G4.
To G6 are about 0.14 and 0.1 respectively.
This is a stable section that is relatively small at 12, 0.11, and has a small change. Furthermore, the amount of PE beads added is 15
In the section from [% by weight] to 25% by weight, the coefficient of static friction in each of the lubricating greases G4 to G6 is about 0.1%.
This is a more stable section that is as small as 2, 0.11, and 0.10 and is almost constant.

Therefore, according to this characteristic diagram, 1.8 [k]
gf / mm ² ], lubricating greases G4 to G6 to which 10% to 25% by weight of PE beads having a particle size of 20 μm are excellent are used. It was found to show lubrication properties. The lubricating greases G4 to G6 in which the amount of the PE beads added was 15 [% by weight] to 25 [% by weight] were more stable because the coefficient of static friction between the plates was almost constant as described above. It was found to show lubrication properties.

Further, according to the characteristic diagram of FIG. 3, in the section where the contact pressure is 0.5 [kgf / mm ² ] to 4.5 [kgf / mm ² ], the PE beads are added in the above range. It can be inferred that the lubricating greases G4 to G6 to which is added has excellent lubricating properties.

As a result, the contact pressure becomes 0.5 [kgf / m
lubricating grease G4~ used between the sliding member of more than m ^2]
In G6, the amount of the PE beads added to the greases G4 to G6 is preferably in the range of 10% by weight to 25% by weight, and is most preferably in the range of 15% by weight to 25% by weight. It can be guessed.

The lubricating grease G5 to which 2% by weight of PTFE powder was added had a smaller static friction resistance than the lubricating grease G4 to which no PTFE powder was added.
It was found that the static grease resistance of lubricating grease G6 to which 4% by weight of FE powder was added was smaller.

As described above, according to the characteristic diagrams shown in FIGS. 3 to 5, the lubricating grease used between the sliding members having a contact pressure exceeding 0.5 [kgf / mm ² ] is added to the grease. When the particle size of the PE beads is in the range of 5 [μm] to 40 [μm], the added amount is 10 [% by weight] to 25 [% by weight].
Range is preferable. In addition, it is estimated that the optimal range of the PE beads added to the lubricating grease is within the range of 10 [μm] to 40 [μm], and the amount of the PE beads is 15 [% by weight] to 25 [% by weight]. it can.

Therefore, based on the above results, the base grease
PE beads having a particle size of 5 [μm] to 40 [μm]
[% By weight] to 25% by weight and used between the worm 4b and the worm wheel 10 of the motor 1 of the present embodiment (between members having a mutual contact pressure of about 2.8 [kgf / mm ² ]). If lubricating grease G is formed, its worm 4b
The friction coefficient between the worm wheels 10 is reduced, the sliding resistance between the worm wheels 10 is reduced, and the loss of the driving force is reduced.

Further, the base grease has a particle diameter of 10 μm.
m] to 40 [μm] of PE beads at 15 [% by weight] to 2
If the lubricating grease G is constituted by adding 5% by weight,
Since the friction coefficient between the worm 4b and the worm wheel 10 is extremely small, the loss of the driving force between the worm 4b and the worm wheel 10 is further reduced.

As described above, according to the present embodiment,
It has the following effects. (1) As shown in FIGS. 3 to 5, 0.5 [kgf / mm
² ] between the sliding members on which the contact pressure of
The use of lubricating grease in which PE beads of [μm] to 40 [μm] is added to the base grease in an amount of 10% by weight or more can reduce the friction coefficient between sliding contact members, and this lubricating grease provides excellent lubrication. It can demonstrate its characteristics.

Further, when PE beads having a particle diameter of 10 [μm] to 40 [μm] are used in an amount of 15% by weight or more and lubricating grease added to the base grease, the friction coefficient between the sliding contact members is improved. It can be made smaller and this lubricating grease can exhibit better lubricating properties.

Further, the lubricating grease having the above composition has a small static friction coefficient even when the lubricating grease is left in an atmosphere of 80 ° C. for 96 hours with a high contact pressure applied between the sliding members, and then its static friction coefficient is measured. Indicates a value. Therefore, the lubricating grease having the above composition can stably exhibit excellent lubricating properties.

(2) Since inexpensive PE beads are used as the solid lubricant, an increase in the cost of lubricating grease can be suppressed. (3) As shown in FIG. 5, PTF is further used as a solid lubricant.
The lubricating grease to which E powder is added can have a smaller static friction resistance than the lubricating grease to which PTFE powder is not added, so that the lubricating grease can have more excellent lubricating characteristics.

(4) Since the lubricating grease having the above configuration is used between the worm 4b and the worm wheel 10 of the motor 1 of the motor 1 of the present embodiment, the loss of the driving force can be reduced and the efficiency is improved. be able to. Accordingly, the motor 1 can be small and have high output. Also, the lubricating grease can improve the wear resistance (durability) of the worm 4b and the worm wheel 10, and can reduce noise generated from the meshing portion. Furthermore, since only lubricating grease needs to be improved, an increase in the cost of the motor 1 can be suppressed.

The embodiment of the present invention may be modified as follows. In the above embodiment, the worm 4 on which a high contact pressure acts
b. Lubricating grease G on the meshing portion between the worm wheels 10
However, it may be used between other sliding contact members on which a high contact pressure acts, for example, between the rotating shaft 4 and the bearings 8, 11, and 12 receiving the radial load of the rotating shaft 4. or,
The rotating shaft 4, a thrust sliding portion 4 a that receives a thrust load of the rotating shaft 4, a thrust receiving member 14, and a thrust plate 1
3 may be used. Further, it may be used between sliding contact members in devices other than the motor 1. In this case, the material of the sliding contact member is not limited to the material shown in the above embodiment.

Incidentally, the present applicant, like the above embodiment,
The composition of the lubricating grease suitable between the rotating shaft 4 (S55C) and the bearings 8, 11, 12 (in the present embodiment, made of Fe-Cu) was studied. In this embodiment, various lubricating greases G7 to G10, which will be described later, are applied to the upper surface of the metal plate made of S55C in order to simulate the sliding portion.
A metal plate made of Fe-Cu was placed on the plate G10, and the plate was pressed against the metal plate made of S55C with a predetermined pressure. Then, the measuring device having such a configuration is
After standing in an atmosphere at 96 ° C. for 96 hours, the coefficient of static friction between the two plates was measured under the following various conditions 1 to 3.

1. The change of the static friction coefficient between the S55C plate and the Fe-Cu plate with the increase in the contact pressure was measured. As shown in FIG. 6, lubricating grease G7 obtained by adding 15% by weight of PE beads to base grease (mineral oil + lithium soap) and lubricating grease G having 0% by weight of PE beads
8 was used to measure the change in the coefficient of static friction. In this case, the particle size of the PE beads was 20 [μm]. No PTFE powder was added to both greases G7 and G8. In this measurement, S55C
The contact pressure between the metal plate and the Fe-Cu metal is 0.25 [kgf / mm ² ] to 4.5 [kgf / m].
m ² ].

According to the characteristic diagram of FIG. 6, the lubricating grease G7,
The coefficient of static friction at G8 changes almost in the same manner as the characteristic diagram of FIG. Therefore, according to this characteristic diagram, the particle size is 2
Lubricating grease G7 containing 15 [wt%] of 0 [μm] PE beads can exhibit excellent lubricating properties when used between plates where a contact pressure exceeding 0.5 [kgf / mm ² ] is applied. understood. Further, the lubricating grease G7 is 1.5
When used between plates on which a contact pressure exceeding [kgf / mm ² ] is applied, the coefficient of static friction between the plates becomes almost constant, and thus it was found that stable lubrication characteristics were exhibited. That is, the lubricating grease G7 is preferably used between the plates on which the contact pressure exceeding 0.5 [kgf / mm ² ] acts, and between the plates on which the contact pressure exceeding 1.5 [kgf / mm ² ] acts. It can be said that it is most suitable to use it.

2. S55C with increasing particle size of PE beads
The change in the coefficient of static friction between the plate and the Fe-Cu plate was measured. As shown in FIG. 7, the particle size of the base grease (mineral oil + lithium soap) is 5 [μm] to 40 [μm].
m], and the coefficient of static friction was measured when the lubricating grease G9 to which 15% by weight of PE beads of each particle size was added was used (the particle size in FIG. 7 was “0”).
Is the static friction coefficient of the lubricating grease G9 when no PE beads are added). In this case, S5
The mutual contact pressure between the 5C metal plate and the Fe-Cu metal plate was kept constant at 1.8 [kgf / mm ² ].

According to the characteristic diagram of FIG. 7, the coefficient of static friction in the lubricating grease G9 changes substantially in the same manner as the characteristic diagram of FIG. Therefore, according to this characteristic diagram, 1.8 [kgf
/ Mm ² ], the lubricating grease G9 to which 15% by weight of PE beads having a particle size of 5 μm to 40 μm is added has excellent lubricating properties. It turned out to show. Further, the particle size is 10 [μm] to 4
It was found that the lubricating grease G9 to which 15 [wt%] of PE beads up to 0 [μm] was added exhibited a more stable lubricating characteristic because the coefficient of static friction between the plates was almost constant.

Further, according to the characteristic diagram shown in FIG. 6, in the section where the contact pressure is 0.5 [kgf / mm ² ] to 4.5 [kgf / mm ² ], PE having a particle diameter within the above range is obtained. It can be inferred that the lubricating grease G9 added with the beads has excellent lubricating properties.

As a result, the contact pressure becomes 0.5 [kgf / m
In the lubricating grease G9 used between the sliding member of more than m ^2], the particle size of the PE beads to be added to the grease G9 5
[Μm] to 40 [μm] is preferable and 10 [μm]
m] to 40 [μm] can be estimated to be optimal.

3. S55 with increasing amount of PE beads added
The change in the coefficient of static friction between the C plate and the Fe-Cu plate was measured. As shown in FIG. 8, base grease (mineral oil +
The static friction coefficient when each lubricating grease G10 in which the amount of PE beads having a particle size of 20 [μm] was increased from 0 [% by weight] to 25 [% by weight] with respect to lithium soap) was measured. . In this case, the mutual contact pressure between the metal plate made of S55C and the metal plate made of Fe-Cu was kept constant at 1.8 [kgf / mm ² ].

According to the characteristic diagram of FIG. 8, the lubricating grease G10
The coefficient of static friction changes in the same manner as in the characteristic diagram of FIG. Therefore, according to this characteristic diagram, 1.8 [kg
f / mm ² ], lubricating grease G10 to which 10% by weight to 25% by weight of PE beads having a particle diameter of 20 μm is used has excellent lubricating properties. It turned out to show. Further, the lubricating grease G10 in which the addition amount of the PE beads is 15 [% by weight] to 25 [% by weight] has a more stable lubricating property because the coefficient of static friction between the plates is almost constant as described above. It turned out to show.

Further, according to the characteristic diagram shown in FIG. 6, in the section where the contact pressure is 0.5 [kgf / mm ² ] to 4.5 [kgf / mm ² ], the PE beads are added in the above range. It can be inferred that the lubricating grease G10 to which is added has excellent lubricating properties.

As a result, the contact pressure becomes 0.5 [kgf / m
lubricating grease G10 used between the sliding member of more than m ^2]
In the above, the addition amount of the PE beads to be added to the grease G10 is preferably in the range of 10% by weight to 25% by weight, and the range of 15% by weight to 25% by weight can be estimated to be optimal. .

In the above embodiment, the addition amount of PE beads was changed to 25% by weight. However, according to the characteristic diagrams of FIGS. 5 and 8, the addition amount of PE beads was increased by 25% by weight or more. However, since it can be estimated that the static friction coefficient does not greatly increase, the addition amount of the PE beads may be appropriately increased to 25% by weight or more.

In the above embodiment, in FIG.
Although the addition amount of the FE powder is 2 [% by weight] and 4 [% by weight], the addition amount is not limited thereto, and the addition amount may be appropriately changed.

In the above embodiment, P is used as the solid lubricant.
Although E beads and PTFE powder are used, other materials, for example, a solid lubricant made of molybdenum, graphite, or the like may be used.

In the above embodiment, the polyalkylene glycol is used as the base oil in FIGS. 3 to 5, but other polyglycol-based oils and non-polyglycol-based oils, for example, diester-based oils and mineral oils May be used as a base oil. Further, a base oil obtained by appropriately mixing a plurality of types of oils may be used. Even in this case, the same effect as the above embodiment can be obtained. In addition, in FIGS. 6 to 8, mineral oil is used as the base oil, but may be appropriately changed in the same manner.

In the above embodiment, lithium soap was used as a thickening agent. However, a thickening agent made of other soap-based materials or a non-soap-based material such as a urea-based material was used. May be used.

In the above embodiment, the motor 1 with the speed reduction mechanism is used as a drive source of the vehicle power window device, but may be used as a drive source of another device mounted on the vehicle, for example, a wiper device. Further, it may be used as a drive source other than the device mounted on the vehicle.

The technical ideas other than the claims that can be grasped from the above embodiments will be described below together with their effects. (B) in the lubricating grease according to any one of claims 1 to 5, and characterized in that the contact pressure of more than 1.5 [kgf / mm ^2] is used between sliding member acting between each other Lubricating grease. In this way, the coefficient of static friction is substantially constant even if the contact pressure between them increases, so that stable lubrication characteristics can be exhibited (see FIGS. 3 and 6).

(B) The lubricating grease according to any one of claims 1 to 5, wherein one of the sliding contact members is made of metal and the other is made of resin. Even when used between such a metal sliding member and a resin sliding member, excellent lubrication characteristics can be exhibited (see FIGS. 3 to 5).

(C) The lubricating grease according to any one of claims 1 to 5, wherein both the sliding contact members are made of metal. Even when used between such metal sliding members, excellent lubricating properties can be exhibited (see FIGS. 6 to 8).

[0071]

As described in detail above, according to the present invention,
It is possible to provide a lubricating grease and a motor with a speed reduction mechanism that can stably exhibit excellent lubricating characteristics even when used between sliding parts where a high contact pressure acts.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a motor with a speed reduction mechanism according to an embodiment.

FIG. 2 is a diagram showing a configuration of lubricating grease.

FIG. 3 is a characteristic diagram showing a change in a coefficient of static friction between sliding members with an increase in contact pressure between the sliding members.

FIG. 4 is a characteristic diagram showing a change in a coefficient of static friction between sliding members as the particle size of PE beads increases.

FIG. 5 is a characteristic diagram showing a change in a coefficient of static friction between sliding members with an increase in the amount of PE beads added.

FIG. 6 is a characteristic diagram showing a change in a coefficient of static friction between sliding members according to an increase in contact pressure between sliding members in another example.

FIG. 7 is a characteristic diagram showing a change in a coefficient of static friction between sliding members with an increase in the particle size of PE beads in another example.

FIG. 8 is a characteristic diagram showing a change in a coefficient of static friction between sliding members with an increase in the amount of PE beads added in another example.

[Explanation of symbols]

3a: bearing recess as a sliding member and a bearing portion; 4 ... rotary shaft as a sliding member and a bearing portion; 4b: worm as a sliding member and a gear meshing portion; 10 ... a sliding member and a gear meshing portion; Worm wheel as, 8,
11, 12: metal bearings as sliding members and bearings,
13 thrust plate as sliding member and bearing,
14 thrust receiving members as sliding members and bearings;
G, G1 to G10: lubricating grease, x: base grease, y
... Polyethylene beads (PE beads) as a solid lubricant.

Claims (6)

[Claims] 1. A lubricating grease which is obtained by adding a solid lubricant to a base grease and which is used between sliding contact members in which a contact pressure exceeding 0.5 [kgf / mm ² ] acts on each other, A lubricating grease comprising a solid lubricant having a particle size of 5 [μm] to 40 [μm], and 10 [wt%] or more of the solid lubricant. 2. The lubricating grease according to claim 1, wherein the solid lubricant has a particle size of 10 [μm] to 40 [μm]. 3. The lubricating grease according to claim 1, wherein the solid lubricant is added in an amount of 15% by weight or more. 4. The lubricating grease according to claim 1, wherein the solid lubricant comprises at least polyethylene beads. 5. The lubricating grease according to claim 4, wherein said solid lubricant further comprises polytetrafluoroethylene powder. 6. A motor with a speed reduction mechanism, wherein the lubricating grease according to any one of claims 1 to 5 is used for at least one of a gear meshing portion and a bearing portion.