WO2020202833A1 - Small gear and gear unit - Google Patents

Abstract

The small gear according to the present invention has a module of 0.2 mm or less. The small gear is formed from a resin composition containing a crystalline resin and a clay mineral, and the amount of the clay mineral contained in the resin composition is 5-20 mass%. It is preferable that the clay mineral is talc, which is a flat-plate-form clay mineral. It is also preferable that the resin composition further contains an olefin-resin-based lubricant and/or a fluororesin-based lubricant.

Description

Small gears and gear units

The present invention relates to small gears and gear units.

Conventionally, a reduction gear (gear unit) using a planetary gear mechanism has been known (see, for example, Patent Document 1). In this speed reducer, planetary gears are manufactured by a metal injection molding (MIM) method, and output gears and fixed gears are manufactured using a resin composition containing an additive. In recent years, attempts have been made to apply such a speed reducer to a small camera or the like, and with the miniaturization of the speed reducer, a smaller gear is required.

However, when a small gear is manufactured by the MIM method, it is difficult to increase the yield because the dimensional accuracy of the obtained gear is low. On the other hand, when a small gear is manufactured using the resin composition, there is a problem that it is easily worn.

Japanese Publication No. 2010-091095

The present invention has been made in view of the above problems, and an object of the present invention is to provide a small gear having excellent wear resistance and a gear unit including such a small gear.

An exemplary invention of the present application is a small gear having a module of 0.2 mm or less.

It is composed of a resin composition containing a crystalline resin and a clay mineral.

The small gear is characterized in that the amount of the clay mineral contained in the resin composition is 5 to 20% by mass.

Further, another exemplary invention of the present application is a gear unit characterized by having the small gear.

According to the exemplary invention of the present application, it is possible to provide a small gear having excellent wear resistance and a gear unit having such a small gear.

FIG. 1 is a side view showing a state in which a combiner is projected from a case body in a head-up display having a built-in gear unit of the present invention. FIG. 2 is a perspective view of a main part of FIG. FIG. 3 is a perspective view in which the frame and the unit case of FIG. 2 are omitted. FIG. 4 is a perspective view of a main part showing a state in which the combiner of FIG. 1 is housed in the case body. FIG. 5 is a side view of FIG. FIG. 6 is a vertical sectional view showing an embodiment of the gear unit of the present invention. 7 is a sectional view taken along line AA and a sectional view taken along line BB in FIG. 6 (reference numerals are shown in parentheses).

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

First, a head-up display to which the gear unit of the present invention is applied will be described prior to the description of the small gear and the gear unit of the present invention.

(Head-up display)

FIG. 1 is a side view showing a state in which the combiner is projected from the case body in a head-up display, FIG. 2 is a perspective view of a main part of FIG. 1, and FIG. 3 omits the frame and unit case of FIG. A perspective view, FIG. 4 is a perspective view of a main part showing a state in which the combiner of FIG. 1 is housed in a case main body, and FIG. 5 is a side view of FIG.

As shown in FIG. 1, a pop-up storage type small head-up display (hereinafter, referred to as “HUD”) 10 includes a case body 11a, a frame 12 fixed inside the case body 11a, and a frame 12. It is provided with two guide shafts 13 fixed to.

The case body 11a has a top plate 11b having an opening through which the combiner 113 of the unit case 14, which will be described later, can pass through. The combiner 113 can project to the outside of the case body 11a by passing through this opening.

As shown in FIG. 2, the frame 12 has a wall plate 12a arranged along the vertical direction, and an upper flange 12b and a lower flange 12c formed at the upper and lower ends of the wall plate 12a and bent in the horizontal direction. It is composed of plate-shaped members. Two guide shafts 13 are provided between the upper flange 12b and the lower flange 12c at a horizontal interval.

Further, the HUD 10 includes a unit case 14 provided so as to be able to move up and down along each guide shaft 13, and a lead screw 15 disposed between the two guide shafts 13 and penetrating the unit case 14. There is.

The unit case 14 has a box shape with an open upper surface.

The upper and lower ends of the lead screw 15 are rotatably supported by bearings 20 and 21 on the upper and lower flanges 12b and 12c, respectively.

As shown in FIGS. 2 and 3, the HUD 10 includes a gear unit 1 and a motor 80 fixed to the lower surface side of the lower flange 12c, a gear (gear) 17 fixed to the output shaft 9 of the gear unit 1, and a lead. A gear (gear) 18 fixed to the lower end of the screw 15 and a nut 19 screwed into the lead screw 15 are provided. Further, a bearing 22 for supporting the output shaft 9 of the gear unit 1 is arranged on the lower flange 12c.

The gear 17 and the gear 18 are both spur gears, the gear 17 is a small gear, and the gear 18 is a large gear. The gear 17 and the gear 18 are in mesh with each other.

Further, the nut 19 is fixed to the unit case 14.

Then, when the motor 80 operates, the gear 17 rotates. This rotational force is transmitted to the gear 18 so that the gear 18 can be rotated together with the lead screw 15. As a result, the nut 19 can move along the lead screw 15 while being screwed into the lead screw 15.

By moving the nut 19 upward, the unit case 14 fixed to the nut 19 can be raised in the case body 11a as shown in FIGS. 2 and 3. Further, when the gear 17 is rotated in the opposite direction to the above by the operation of the motor 80, the unit case 14 is moved to the case main body 11a as shown in FIGS. 4 and 5 due to the downward movement of the nut 19. Can descend within.

That is, at least the lead screw 15 to which the gear 18 is fixed, the gear (drive gear) 17 arranged so as to mesh with the gear 19, and the motor (drive unit) 80 for driving the gear 17 make the drive device of the HUD 10 It is composed.

As shown in FIG. 3, the HUD 10 includes a rotating shaft 110 rotatably supported in the unit case 14, a base portion 111 fixed to the central portion of the rotating shaft 110 in the longitudinal direction, and a base. The combiner holder 112 provided in the portion 111 and the combiner 113 attached to the combiner holder 112 are provided.

The rotation shaft 110 is arranged in the horizontal direction and can rotate around the axis.

The base portion 111 has a diameter larger than that of the rotating shaft 110, and a screw 111a is formed on the lower half circumference thereof.

Further, a flat plate-shaped combiner holder 112 is provided on the outer periphery of the base portion 111 on the upper side in parallel with the rotation shaft 110. The upper part of the combiner holder 112 protrudes from the upper opening of the unit case 14.

The lower end of the combiner 113 is attached to this protruding portion. The combiner 113 has a plate shape and is arranged along the vertical direction.

In the case main body 11a, a projection unit (not shown) for projecting an image toward the combiner 113 is arranged adjacent to the elevating region of the frame 12 and the unit case 14.

As shown in FIG. 3, the HUD 10 includes a pinion gear 114 rotatably provided in the unit case 14, a helical gear 115 integrally formed in the pinion gear 114, and a tilt motor 116 mounted in the unit case 14. And a worm gear 117 fixed to the output shaft of the motor 116.

In the HUD 10, a rotation mechanism for rotating the rotation shaft 110 is configured by a screw 111a of the base portion 111, a pinion gear 114, a helical gear 115, and a worm gear 117.

The axis of the pinion gear 114 is provided parallel to the rotating shaft 110, and is screwed (meshed) with the screw 111a.

A helical gear 115 having a diameter larger than that of the pinion gear 114 is arranged on one end side of the pinion gear 114. The pinion gear 114 and the helical gear 115 are arranged coaxially and can rotate in synchronization with each other.

The output shaft of the motor 116 is arranged along the vertical direction.

Further, the worm gear 117 is fixed to the output shaft of the motor 116, and can be rotated around the output shaft by the operation of the motor 116. The worm gear 117 meshes with (tooths) the helical gear 115.

In the HUD 10 having the above configuration, as described above, when the lead screw 15 is rotated by the operation of the motor 80, the unit case 14 together with the nut 19 screwed into the lead screw 15 can be raised along the guide shaft 13. it can. As a result, as shown in FIGS. 1 to 3, the combiner 113 provided in the upper part of the unit case 14 can pass through the opening of the case body 11a and project to the outside of the case body 11a.

Then, when the motor 116 is operated in this protruding state, the worm gear 117 rotates, and the rotational force is transmitted to the helical gear 115. As a result, the helical gear 115 can be rotated together with the pinion gear 114. Further, the rotational force of the pinion gear 114 is transmitted to the rotating shaft 110 via the screw 111a. As a result, the rotation shaft 110 can be rotated together with the combiner 113, and thus the inclination angle of the combiner 113 with respect to the projection unit can be adjusted. An image (image) from the projection unit is accurately projected onto the combiner 113 whose inclination angle is adjusted.

After using the combiner 113, the motor 116 operates to bring the combiner 113 upright, that is, to restore the tilt angle. Then, the motor 80 is operated to rotate the lead screw 15 in the direction opposite to the above, so that the unit case 14 is lowered along the guide shaft 13. As a result, as shown in FIGS. 4 and 5, the combiner 113 can be stored in the case body 11a.

A hole penetrating in the axial direction is formed in the gear 18, and the gear 18 is fixed to the lead screw 15 with the end of the lead screw 15 inserted into the hole.

(Gear unit)

FIG. 6 is a vertical sectional view showing an embodiment of the gear unit of the present invention. FIG. 7 is a sectional view taken along line AA and a sectional view taken along line BB in FIG. 6 (reference numerals are shown in parentheses).

Note that FIG. 6 shows a cross section of the gear unit 1 with a surface including the central axis J1. Further, in the following, for convenience of explanation, the upper side in FIG. 6 is referred to as "upper" or "upper", and the lower side is referred to as "lower" or "lower".

Further, in the following description, the vertical direction, which is the direction in which the central axis J1 faces, is also referred to as "axial direction". Further, in the following description, the circumferential direction centered on the central axis J1 is simply referred to as "circumferential direction", and the radial direction centered on the central axis J1 is simply referred to as "diameter direction".

As shown in FIG. 6, the gear unit 1 includes a casing 2, an input unit 3, a first rotary assembly 4, a second rotary assembly 6, a first internal gear 5, and a second internal gear 7. , The input shaft 8 and the output shaft 9 are provided. A motor 80 is directly connected to the input shaft 8.

The gear unit 1 has a planetary gear mechanism having a two-stage configuration of a first rotating assembly 4 and a second rotating assembly 6, and is formed, for example, having an external dimension of 5 mm in width, 5 mm in depth, and 20 mm in height or less. ing.

<Motor>

The motor 80 serves as a drive source, that is, a power source for a structure (not shown) on which the gear unit 1 is mounted. In addition to the small HUD10 shown in FIG. 1, the structure may be, for example, a small camera or the like. Further, for the motor 80 and the motor 116, for example, a stepping motor, a servo motor, or the like is appropriately selected depending on the intended use of the structure.

Further, the input shaft 8 may be the motor shaft of the motor 80 that is rotationally driven with the central shaft J1 as the center of rotation.

<Casing>

A casing 2 is arranged and fixed on the upper side of the motor 80. The casing 2 has a substantially cylindrical shape centered on the central axis J1. The input unit 3, the first rotary assembly 4, a part of the second rotary assembly 6, the first internal gear 5, and the second internal gear 7 are housed inside the casing 2. In FIG. 6, the second rotating assembly 6 side is on the upper side and the first rotating assembly 4 side is on the lower side along the central axis J1, but the direction of the central axis J1 must always match the direction of gravity. There is no. Further, the gear ratio between the first rotary assembly 4 and the second rotary assembly 6 is appropriately set depending on the intended use of the structure. As a result, the power from the motor 15 can be decelerated and output from the output shaft 9.

<Input section>

The input unit 3 includes a second input shaft 31 and an input gear 33.

The second input shaft 31 is connected to the upper part of the input shaft 8 and can rotate around the central axis J1 together with the input shaft 8. The second input shaft 31 has a substantially cylindrical shape or a substantially cylindrical shape, and its outer diameter is smaller than the outer diameter of the input shaft 8.

The input gear 33 is concentrically fixed to the outer peripheral portion of the second input shaft 31. As a result, the input gear 33 can rotate around the central axis J1 together with the second input shaft 31. The method of fixing the input gear 33 to the second input shaft 31 is not particularly limited, and for example, a fixing method using a key and a keyway can be used. Further, the second input shaft 31 and the input gear 33 are separately formed from each other in the illustrated configuration, but the present invention is not limited to this, and for example, the second input shaft 31 and the input gear 33 may be integrally formed of one gear member. ..

As shown in FIG. 7, the input gear 33 is a spur gear having a plurality of teeth (hereinafter, referred to as “outer peripheral teeth”) 331 protruding from the outer peripheral portion thereof.

<1st rotary assembly>

The first rotary assembly 4 includes a first rotary shaft member 41, a first planetary carrier 42, a plurality of first planetary shaft members 43, a plurality of first planetary gears 44, and a sun gear 45.

In the first rotary assembly 4, the first rotary shaft member 41, the first planetary carrier 42, and the plurality of first planetary shaft members 43 are supports that support the first planetary gear 44 and the sun gear 45, respectively. This support may include yet another member in addition to the first rotating shaft member 41, the first planetary carrier 42, and the plurality of first planetary shaft members 43.

The first rotating shaft member 41, the first planetary carrier 42, and the plurality of first planetary shaft members 43 are integrally formed of one gear member in the present embodiment, but the present invention is not limited to this, and for example, each other. It may be composed of separate bodies, and may be composed of a connected body in which these separate bodies are connected to each other.

The first rotating shaft member 41 has a substantially cylindrical shape or a substantially cylindrical shape, and its central axis coincides with the central axis J1. Further, the first rotary shaft member 41 is arranged above the second input shaft 31 of the input unit 3.

A disk-shaped first planet carrier 42 is arranged concentrically with the first rotating shaft member 41 below the first rotating shaft member 41. That is, the first rotation shaft member 41 is arranged so as to project upward at the center of the disk-shaped first planet carrier 42.

A plurality of first planetary shaft members 43 are arranged below the first planetary carrier 42 on the outer peripheral side of the first planetary carrier 42, that is, at positions eccentric from the central axis J1 (first rotating shaft member 41). .. The plurality of first planetary shaft members 43 have the same substantially cylindrical shape, and their longitudinal directions are oriented along the central axis J1 (hereinafter, also referred to as "along the central axis J1"). There is.

The number of arrangements of the first planetary shaft members 43 is not limited to three in the configuration shown in FIG. 2, but may be two or four or more. Further, these first planetary shaft members 43 are arranged at equal angular intervals around the central axis J1. For example, as shown in FIG. 2, when the number of arrangements of the first planetary shaft members 43 is three, these first planetary shaft members 43 are arranged at intervals of 120 ° around the central axis J1. In the following description, the central axis of each first planetary axis member 43 will be referred to as "first planetary axis J2".

A first planetary gear 44 is rotatably supported (rotatably) on each first planetary shaft member 43. As a result, each of the first planetary gears 44 can rotate around the first planetary axis J2, that is, rotate on its axis. Further, each of the first planetary gears 44 can rotate around the central axis J1 as the center of rotation, that is, revolve. As described above, each of the first planetary gears 44 is a planetary gear (also referred to as "P gear") that rotates around the first planetary axis J2 and revolves around the central axis J1.

Each first planetary gear 44 is a spur gear having a plurality of teeth (hereinafter, referred to as "outer peripheral teeth") 441 protruding from the outer peripheral portion thereof. Each of the first planetary gears 44 is arranged on the outer side in the radial direction of the input gear 33 along the circumferential direction thereof, and the outer peripheral teeth 441 are engaged (engaged) with the outer peripheral teeth 331 of the input gear 33.

The sun gear 45 is concentrically fixed to the outer peripheral portion of the first rotary shaft member 41. As a result, the sun gear 45 can rotate around the central axis J1 together with the first rotating shaft member 41. The method of fixing the sun gear 45 to the first rotary shaft member 41 is not particularly limited, and for example, a fixing method using a key and a key groove can be used. The sun gear 45 is a spur gear having a plurality of teeth (hereinafter, referred to as “outer peripheral teeth”) 451 protruding from the outer peripheral portion thereof.

Further, the first rotary shaft member 41 and the sun gear 45 are separately formed from each other in the illustrated configuration, but the present invention is not limited to this, and for example, even if the first rotary shaft member 41 and the sun gear 45 are integrally formed of one gear member. Good. Therefore, the first rotating shaft member 41, the first planetary carrier 42, the plurality of first planetary shaft members 43, and the sun gear 45 may be integrally formed of one gear member, and the gear member is referred to as "C. Also called "gear".

<1st internal gear>

The first internal gear 5 forms an annular shape with the central axis J1 as the central axis. The first internal gear 5 is arranged and fixed concentrically with the casing 2 inside the casing 2. The fixing method is not particularly limited, and for example, a fixing method by fitting can be used. In this case, intermediate fitting is preferable.

As shown in FIG. 7, the first internal gear 5 is an internal gear having a plurality of teeth (hereinafter, referred to as “inner peripheral teeth”) 51 protruding from the inner peripheral portion thereof. The inner peripheral teeth 51 mesh with the outer peripheral teeth 441 of each of the first planetary gears 44 at different positions in the circumferential direction.

<Second rotation assembly>

The second rotary assembly 6 is arranged above the first rotary assembly. The second rotary assembly 6 includes a second rotary shaft member 61, a second planet carrier 62, a plurality of second planet shaft members 63, and a plurality of second planet gears 64.

In the second rotary assembly 6, the second rotary shaft member 61, the second planet carrier 62, and the plurality of second planet shaft members 63 are supports that support each of the second planet shaft members 63. The support may include yet another member in addition to the second rotating shaft member 61, the second planet carrier 62, and the plurality of second planetary shaft members 63.

In the present embodiment, the second rotating shaft member 61, the second planet carrier 62, and the plurality of second planet shaft members 63 are integrally formed of one gear member, but the present invention is not limited to this, and for example, each other. It may be composed of separate bodies, and may be composed of a connected body in which these separate bodies are connected to each other.

The second rotating shaft member 61 has a substantially cylindrical shape or a substantially cylindrical shape, and its central axis coincides with the central axis J1 like the first rotating shaft member 41. Further, the second rotary shaft member 61 projects upward from the upper surface of the casing 2 to the outside of the casing 2.

A disk-shaped second planet carrier 62 is arranged concentrically with the second rotating shaft member 61 below the second rotating shaft member 61. That is, the second rotating shaft member 61 is arranged so as to project upward at the center of the disk-shaped second planet carrier 62.

A plurality of second planetary shaft members 63 are arranged below the second planetary carrier 62 on the outer peripheral side of the second planetary carrier 62, that is, at a position eccentric from the central axis J1 (second rotating shaft member 61). .. The plurality of second planetary shaft members 63 have the same substantially cylindrical shape, and are arranged so that their longitudinal directions are directed along the central axis J1 (along the central axis J1).

The number of arrangements of the second planetary shaft member 63 is not limited to three in the configuration shown in FIG. 7, but may be two or four or more, and in particular, the first planetary shaft member 43. It is preferable that the number is the same as the number of arrangements of.

Further, these second planetary shaft members 63 are arranged around the central axis J1 at equal angular intervals. For example, as shown in FIG. 7, when the number of arrangements of the second planetary shaft members 63 is three, these second planetary shaft members 63 are arranged around the central axis J1 at intervals of 120 °. In the following description, the central axis of each second planetary axis member 63 will be referred to as "second planetary axis J3".

A second planetary gear 64 is rotatably supported (rotatably) on each of the second planetary shaft members 63. As a result, each of the second planetary gears 64 can rotate around the second planetary axis J3, that is, rotate on its axis. Further, each of the second planetary gears 64 can rotate around the central axis J1 as the center of rotation, that is, revolve. As described above, each of the second planetary gears 64 is a planetary gear (also referred to as “P gear”) that rotates around the second planetary axis J3 and revolves around the central axis J1.

Each second planetary gear 64 is a spur gear having a plurality of teeth (hereinafter, referred to as "outer peripheral teeth") 641 protruding from the outer peripheral portion thereof. Each of the second planetary gears 64 is arranged on the outer side in the radial direction of the sun gear 45 along the circumferential direction thereof, and the outer peripheral teeth 641 are engaged (engaged) with the outer peripheral teeth 451 of the sun gear 45.

<2nd internal gear>

The second internal gear 7 forms an annular shape with the central axis J1 as the central axis. The second internal gear 7 is arranged inside the casing 2 above the first internal gear 5 and apart from the first internal gear 5 in the axial direction.

Further, the second internal gear 7 is arranged and fixed concentrically with the casing 2. The fixing method is not particularly limited, and for example, a fixing method by fitting can be used. In this case, intermediate fitting is preferable.

The second internal gear 7 is an internal gear having a plurality of teeth (hereinafter referred to as “inner peripheral teeth”) 71 protruding from the inner peripheral portion thereof. The inner peripheral teeth 71 mesh with the outer peripheral teeth 641 of each of the second planetary gears 64 at different positions in the circumferential direction.

<Output shaft>

The output shaft 9 is connected (connected) to the upper part of the second rotary shaft member 61 on the outside of the casing 2, and can rotate around the central shaft J1 together with the second rotary shaft member 61. The output shaft 9 has a substantially cylindrical shape or a substantially cylindrical shape, and its outer diameter is the same as the outer diameter of the second rotating shaft member 61.

<Gear unit operation>

As described above, in the gear unit 1, the gear ratio between the first rotary assembly 4 and the second rotary assembly 6 is set within a predetermined range.

First, when the motor 15 operates, its power is transmitted to the input gear 33 via the input shaft 8 and the second input shaft 31 in order. As a result, as shown in FIG. 7, the input gear 33 rotates around the central axis J1 in the direction of the arrow α1.

Then, the rotational force of the input gear 33 is transmitted to each of the first planetary gears 44 that mesh with the input gear 33. As a result, as shown in FIG. 7, each first planetary gear 44 can rotate around the first planetary axis J2 in the direction of arrow α2, that is, rotate on its axis.

Further, each of the first planetary gears 44 also meshes with the first internal gear 5 fixed to the casing 2. As a result, as shown in FIG. 7, when each of the first planetary gears 44 rotates in the direction of the arrow α2, the rotational force thereof can be transmitted to the first internal gear 5, and thus the arrow around the central axis J1. It can also rotate in the α3 direction, that is, it can revolve. By this revolution, the sun gear 45 can be rotated around the central axis J1 in the direction of arrow β1.

Further, each second planetary gear 64 meshes with the sun gear 45. As a result, when the sun gear 45 rotates in the direction of arrow β1, the rotational force is transmitted to each second planetary gear 64. Then, by this transmission, as shown in FIG. 7, each of the two planetary gears 64 can rotate around the second planetary axis J3 in the arrow β2 direction, that is, rotate.

Further, each of the second planetary gears 64 also meshes with the second internal gear 7 fixed to the casing 2. As a result, as shown in FIG. 7, when each of the second planetary gears 64 rotates in the direction of the arrow β2, the rotational force thereof can be transmitted to the second internal gear 7, and thus the arrow around the central axis J1. It can rotate in the β3 direction, that is, revolve. Then, by this revolution, the output shaft 9 can be rotated around the central axis J1 in the same direction as the arrow β1 direction.

Due to the above force transmission, the decelerated power is output from the output shaft 9.

In the configuration described above, the direction along the central axis J1 means a direction substantially parallel to the central axis J1 (axial direction), and does not have to be strictly parallel to the axial direction. That is, the first planetary axis J2 and the second planetary axis J3 may be parallel to the central axis J1 or may be inclined by a small angle with respect to the central axis J1.

(gear)

In the HUD 1 and the gear unit 1 having the above configuration, the small gear of the present invention is preferably used as a gear that rotates (rotates and / or revolves) itself. Specifically, in the gear unit 1 shown in FIG. 6 and the like, at least one of an input gear 33, a C gear (gear member), and a plurality of P gears (first planetary gear 44 and second planetary gear 64). Is preferably composed of the small gear of the present invention.

The small gear of the present invention (hereinafter, also simply referred to as a gear) has a module of 0.2 mm or less, and is composed of a resin composition containing a crystalline resin and a clay mineral.

The crystalline resin refers to a thermoplastic resin having a melting peak when differential scanning calorimetry (DSC) is performed in accordance with JIS K 7121: 2012 (plastic transition temperature measuring method).

Examples of the crystalline resin include polyamide, polyolefin, polyester, polyether, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polyacetal (POM), polyimide, fluoropolymer and the like. In addition. These resins may be used alone or in combination of two or more. Of these, polyamide is preferable as the crystalline resin. Polyamide can be used to improve the mechanical strength, rigidity and wear resistance of gears.

Polyamides are generally classified into aliphatic polyamides (non-aromatic polyamides), semi-aromatic polyamides, and total aromatic polyamides, but semi-aromatic polyamides are preferable. Semi-aromatic polyamides are preferable because they are easy to melt and crystallize.

The semi-aromatic polyamide is a copolymer of a dicarboxylic acid and a diamine, one of which has an aromatic group and the other of which has an aliphatic group.

Examples of the aliphatic dicarboxylic acid include HOOC- (CH ₂ ) _n- COOH (n is 0 to 12), dimethylmalonic acid, 3,3-diethylsuccinic acid, 2,2-dimethylglutaric acid, and 2-methyladipine. Acids, chain aliphatic dicarboxylic acids such as trimethylazipic acid, 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, cycloheptanedicarboxylic acid, cyclooctanedicarboxylic acid , Alicyclic dicarboxylic acid such as cyclodecanedicarboxylic acid and the like.

On the other hand, examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenylic acid and 4,4'-biphenyl. Examples thereof include dicarboxylic acid, diphenylmethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid and the like.

Examples of the aliphatic diamine include linear aliphatic diamines such as NH _2- (CH ₂ ) _m- NH ₂ (m is 0 to 12), 1-butyl-1,2-ethanediamine, and the like. 1,1-dimethyl-1,4-butanediamine, 1-ethyl-1,4-butanediamine, 1,2-dimethyl-1,4-butanediamine, 2-methyl-1,5-pentanediamine, 3- Methyl-1,5-pentanediamine, 2,5-dimethyl-1,6-hexanediamine, 2,4-dimethyl-1,6-hexanediamine, 2,2-dimethyl-1,6-hexanediamine, 1, Branches such as 3-dimethyl-1,8-octanediamine, 2,4-dimethyl-1,8-octanediamine, 2,2-dimethyl-1,8-octanediamine, 5-methyl-1,9-nonanediamine Examples thereof include alicyclic diamines such as aliphatic diamines, cyclohexanediamines, methylcyclohexanediamines, isophoronediamines, norbornenedimethylamines and tricyclodecanedimethyldiamines.

On the other hand, examples of the aromatic diamine include p-phenylenediamine, m-phenylenediamine, p-xylylenediamine, m-xylylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, and 4 , 4'-diaminodiphenyl ether and the like.

Specific examples of the semi-aromatic polyamide include polyamide MXD6 (PAMXD6), polyamide 9T (PA9T), polyamide 4T (PA4T), polyamide 6T (PA6T), and polyamide 10T (PA10T).

Specific examples of other polyamides include, for example, polyamide 6 (PA6), polyamide 11 (PA11), polyamide 12 (PA12) polyamide 66 (PA66), polyamide 610 (PA610), polyamide 612 (PA612), and polyamide 410. (PA410) and the like.

Examples of the polyolefin include polyethylene (PE) and polypropylene (PP).

Examples of the polyester include polyethylene terephthalate (PET), polybutadiene terephthalate (PBT), polylactic acid (PLA) and the like.

Examples of the polyether include polyetheretherketone (PEEK), polyetherketone (PEK), polyetherketone ketone (PEKK), polyaryletherketone (PAEK), and the like.

The melting point of the crystalline resin depends on the type, but is preferably about 165 to 390 ° C, more preferably about 175 to 375 ° C, and even more preferably about 185 to 360 ° C. ..

Clay mineral is a component mixed with a crystalline resin for the purpose of improving the moldability of the resin composition, the slidability of the obtained gear, the rigidity (particularly the bending rigidity), and the like. The obtained gear exhibits excellent durability by improving slidability and flexural rigidity.

Clay minerals have an extremely fine shape as compared with fibrous fillers such as glass fiber and carbon fiber. Therefore, when a small gear having a module of 0.2 mm or less is manufactured, the filling property of the resin composition in the molding die is improved, and thus the obtained gear is also excellent in shape stability.

Examples of clay minerals include flat (scaly) clay minerals such as talc and mica, and particulate clay minerals such as clay (bentonite), kaolin, diatomaceous earth, and wollastonite. Above all, the clay mineral is preferably a flat clay mineral. By using a flat clay mineral, the smoothness of the surface of the gear is increased, so that the slidability (wear resistance) of the gear can be further improved.

The Mohs hardness of the clay mineral is preferably 4 or less, more preferably 3 or less, and further preferably about 1 to 2.

Therefore, the clay mineral is particularly preferably talc (Mohs hardness: about 1). By using talc, the smoothness and bending rigidity of the surface of the gear are increased, and the deformation of the gear can be prevented or suppressed during use. As a result, even if the gear is used for a long time under a high load, wear debris and damage to the gear (particularly the tooth tip) are unlikely to occur.

Further, since talc also has an action of promoting crystallization of the crystalline resin, it is preferable from the viewpoint that the mechanical strength of the obtained gear can be further increased.

In addition, since talc is an inexpensive material as compared with other reinforcing materials (for example, inorganic whiskers described later), it also contributes to reduction of gear manufacturing cost.

The amount of clay mineral contained in the resin composition is about 5 to 20% by mass. By setting the amount of clay minerals in the resin composition within the above range, the effect of improving the characteristics of the obtained gear (particularly, slidability) and the effect of improving the moldability of the resin composition are exhibited in a well-balanced manner. Will be done. The amount of clay mineral contained in the resin composition is preferably about 7.5 to 17.5% by mass, and more preferably about 10 to 15% by mass. As a result, the above-mentioned effect is more prominently exhibited.

Further, the resin composition constituting the gear of the present invention may contain components other than the crystalline resin and the clay mineral.

Examples of such components include inorganic fillers, organic fillers, lubricants and the like.

Examples of the inorganic filler include fibrous inorganic fillers (inorganic fibers), particles (powder) -like inorganic fillers (inorganic spherical particles), and non-fibrous inorganic fillers such as scaly inorganic fillers. ..

Examples of the inorganic fiber include glass fiber, carbon fiber, asbestos fiber, and inorganic whisker (potassium titanate fiber, zinc oxide fiber, magnesium oxide fiber, aluminum oxide fiber, calcium sulfate fiber, silicon carbide fiber, silicon nitride fiber, silicon nitride). Fibers, mulite fibers, magnesium borate fibers, titanium borate fibers, etc.) and the like.

Examples of the inorganic spherical particles include silica spherical particles, alumina spherical particles, quartz particles, glass beads and the like.

Further, examples of the scaly inorganic filler include various metal pieces and the like.

Among them, the inorganic filler is preferably inorganic spherical particles, more preferably inorganic spherical particles having a Mohs hardness of 5 or more (particularly 6 or more), silica spherical particles (Mohs hardness: about 7), and alumina spherical particles. It is more preferable that it is at least one of the particles (Mohs hardness: about 8 to 9).

When the resin composition contains inorganic spherical particles, the resistance to the load of the obtained gear is increased. That is, even if a high load is applied to the gear, the surface thereof is preferably prevented from being dented. In addition, some of the inorganic spherical particles having a higher hardness than the crystalline resin are exposed on the surface of the gear. Therefore, the slidability of the gear is further improved, and as a result, the wear resistance is further improved. .. In particular, by using silica spherical particles, the above effect is more prominently exhibited.

The volume average particle diameter of the inorganic spherical particles is preferably about 2 to 10 μm, and more preferably about 4 to 8 μm. By using the inorganic spherical particles having such a volume average particle diameter, the inorganic spherical particles can be generated when the gear slides with another gear while suppressing deterioration of the surface condition (reduction of smoothness) of the gear. It is possible to preferably prevent the gear from falling off from the surface of the gear.

Here, the volume average particle size is, for example, the particle size at a point where the cumulative volume is 50% in the particle size distribution measured by using a laser diffraction particle size distribution measuring device.

The amount of the inorganic spherical particles contained in the resin composition is preferably about 1 to 10% by mass, and more preferably about 3 to 8% by mass. By using a resin composition containing inorganic spherical particles in such an amount, the wear resistance of the gear can be further improved.

The resin composition does not contain inorganic fibers, or even if the resin composition contains inorganic fibers, the amount thereof is preferably less than 1% by mass. In this case, wear of the gear starting from the inorganic fiber can be prevented.

The organic filler is not particularly limited, and examples thereof include fillers composed of aramid, liquid crystal polymer, polyester, polyolefin, and the like.

Above all, the organic filler preferably contains at least one of an aramid filler and a liquid crystal polymer filler. By using such an organic filler, the mechanical strength of the gear is further increased, and excellent impact resistance can be imparted to the gear. As a result, the durability of the gear is further improved.

The organic filler may be in the form of fibers or particles, but is preferably in the form of fibers. By using the fibrous organic filler (organic fiber), the smoothness of the surface of the gear is further improved, and thus the slidability (wear resistance) of the gear is further improved.

In this case, the average fiber length of the organic fibers is preferably about 100 to 500 μm, more preferably about 150 to 400 μm. By using an organic fiber having such an average fiber length, the above effect is more prominently exhibited.

Here, the average fiber length refers to the average value of the lengths of the fillers in the longitudinal direction.

The amount of the organic filler contained in the resin composition is preferably about 1 to 10% by mass, and more preferably about 2 to 8% by mass. By using a resin composition containing an organic filler in such an amount, the mechanical strength and impact resistance of the gear can be further improved.

Examples of the lubricant include an olefin resin-based lubricant, a fluororesin-based lubricant, an ester resin-based lubricant, an acrylic resin-based lubricant, a polyamide-based lubricant, and the like, but at least one of the olefin resin-based lubricant and the fluororesin-based lubricant. Is preferable. By using such a lubricant, the slidability of the gear can be further improved.

Above all, when the olefin resin-based lubricant is used, the above effect is more remarkablely exhibited by coating the surface of the gear with the lubricant melted by the frictional heat.

The amount of the lubricant contained in the resin composition is preferably about 1 to 10% by mass, and more preferably about 2 to 8% by mass. By using a resin composition containing a lubricant in such an amount, the slidability of the gear can be further improved.

The gear module to be manufactured is 0.2 mm or less, but more preferably about 0.1 to 0.2 mm. Even such a minute gear can be stably manufactured (with a high yield) with accurate dimensions by using the above-mentioned resin composition.

The fine gear preferably has a reference circular pitch diameter of about 1.2 to 1.7 mm, a number of teeth of about 8 to 18, and a tooth thickness of about 0.15 to 0.32 mm.

As described above, in the gear unit 1 shown in FIG. 6 and the like, preferably, at least one of the input gear 33, the C gear (gear member) and the plurality of P gears (first planetary gear 44 and second planetary gear 64) One is composed of the small gear of the present invention.

In particular, since the input gear 33 arranged close to the motor 80 is easily affected by the heat generated by the motor 80, it may be composed of a gear manufactured by using a resin composition containing a semi-aromatic polyimide. preferable.

<Gear manufacturing method>

The gear having the above configuration is manufactured by, for example, the gear manufacturing method described below.

The gear manufacturing method of the present embodiment includes [1] a first step of preparing the resin composition described above, [2] a second step of melting the resin composition, and [3] a resin composition in a molten state. It has a step of supplying a product to a molding die to obtain a molded body having a shape corresponding to a gear to be manufactured, and a step of [4] heat-treating the molded body to obtain a gear.

[1] First step

First, the components (crystalline resin, clay mineral,, if necessary, inorganic filler, organic filler, lubricant) constituting the resin composition are prepared.

By mixing these components, a resin composition is obtained.

Various mixers such as blenders, kneaders, rolls and extruders can be used for this mixing.

[2] Second step

Next, the obtained resin composition is melted by heating it to a temperature higher than the melting point of the crystalline resin.

The heating temperature is preferably about 5 to 20 ° C. higher than the melting point of the crystalline resin, and more preferably about 5 to 15 ° C. higher.

[3] Third step

Next, for example, by an injection molding method, a molten resin composition is supplied to a molding die to obtain a molded body having a shape corresponding to a gear to be manufactured.

The temperature of the molding die is not particularly limited, but is preferably set to a temperature about 5 to 25 ° C. lower than the glass transition temperature (Tg) of the crystalline resin, and more preferably about 10 to 20 ° C. lower.

When the resin composition is supplied to the molding die by setting the temperature of the molding die to a temperature about 5 to 25 ° C. lower than the glass transition temperature (Tg) of the crystalline resin, the resin composition rapidly solidifies and is molded. Become a body. Therefore, since the resin composition is difficult to stretch, the gate is cut well, and the shape (contour shape) of the edge portion of the molded body is also stabilized. Further, the mold releasability of the molded product from the molding mold is enhanced.

Therefore, the time required for forming the molded product can be sufficiently shortened (about 10 to 15 seconds). Therefore, the yield in the production of the molded product can be improved, and the number of installation equipment for manufacturing the molded product can be significantly reduced.

At this point, the crystallization of the crystallization resin has not substantially progressed.

[4] Fourth step

Next, the molded product is taken out from the molding mold and heat-treated (annealed) at a temperature higher than the crystallization temperature of the crystalline resin to obtain a gear. At this time, as a result of the crystallization of the crystalline resin progressing in the molded body, the crystallinity of the molded body is increased.

Here, the crystallinity temperature refers to the exothermic peak temperature associated with the promotion of crystallization of the crystallinity resin when the differential scanning calorimetry is performed on the crystallinity resin under a temperature rising condition of 10 ° C./min.

The temperature of the heat treatment may be higher than the crystallization temperature of the crystalline resin, but is 5 to 25 ° C higher than the maximum temperature when the gear is actually used (hereinafter, also referred to as “actual operating temperature”). The temperature is preferable, and the temperature is more preferably about 10 to 20 ° C. higher than the actual operating temperature. By performing the heat treatment at such a temperature, dimensional stability during use of the gear can be ensured.

In the case of the gear used for the gear unit 1, the actual operating temperature thereof is preferably about 110 to 140 ° C, more preferably about 120 to 130 ° C.

Examples of the method of this heat treatment include a method of heating with a heater, a method of irradiating infrared rays, a method of blowing hot air, and the like in a heating furnace. The heating furnace may be either a batch furnace or a continuous furnace.

The pressure in the heat treatment atmosphere may be reduced pressure, normal pressure or pressurized.

The heat treatment time is not particularly limited, but is preferably about 30 to 120 minutes, and more preferably about 45 to 100 minutes.

The gear is manufactured through the above steps.

The small gear and the gear unit of the present invention have been described above based on preferred embodiments, but the present invention is not limited thereto.

Further, the small gear of the present invention includes parts for industrial machines such as a small camera and a robot hand, as well as, for example, automobile parts, bicycle parts, railroad vehicle parts, marine parts, aircraft parts, and space transport machines. For transportation equipment parts such as parts for personal computers, parts for personal computers, parts for electronic equipment such as parts for mobile terminals, parts for electrical equipment such as refrigerators, washing machines, and air conditioners, parts for plants, parts for watches, etc. Used.

Next, examples of the present invention will be described.

1. 1. Gear manufacturing

(Example 1)

First, a semi-aromatic polyamide (PA9T) as a crystalline resin, talc as a clay mineral, silica spherical particles as inorganic spherical particles, and an olefin resin lubricant as a lubricant were mixed with a blender to obtain a resin composition. ..

The Tg of the aromatic polyamide was about 100 ° C., and the volume average particle size of the silica spherical particles was 6 μm. The amount of talc in the resin composition was 5% by mass, the amount of silica spherical particles was 5% by mass, and the amount of olefin resin-based lubricant was 5% by mass.

Next, this resin composition was supplied to a molding die set at about 80 ° C. to obtain a molded body having a shape corresponding to the gear to be manufactured. After confirming that the molded product had solidified, 11 seconds after the resin composition was supplied to the mold, the molded product was taken out from the mold.

Then, the obtained molded product was heat-treated at 150 ° C. for 60 minutes in a heating furnace to obtain gears. The target gear had a reference circular pitch diameter of 1.3 mm, a module of 0.2 mm, a number of teeth of 14, and a tooth thickness of 0.4 mm.

(Example 2)

Gears were obtained in the same manner as in Example 1 except that the amount of talc in the resin composition was 7.5% by mass.

(Example 3)

Gears were obtained in the same manner as in Example 1 except that the amount of talc in the resin composition was 10% by mass.

(Example 4)

Gears were obtained in the same manner as in Example 3 except that the lubricant was omitted.

(Example 5)

Gears were obtained in the same manner as in Example 1 except that the amount of talc in the resin composition was 17.5% by mass.

(Example 6)

Gears were obtained in the same manner as in Example 1 except that the amount of talc in the resin composition was 20% by mass.

(Comparison example)

Gears were obtained in the same manner as in Example 1 except that the resin composition was prepared as follows.

A semi-aromatic polyamide (PA9T) as a crystalline resin, potassium titanate fiber as an inorganic whisker, and an olefin resin-based lubricant as a lubricant were mixed with a blender to obtain a resin composition.

The amount of potassium titanate fibers in the resin composition was 30% by mass, and the amount of the olefin resin-based lubricant was 5% by mass.

In each of the examples and comparative examples, 100 gears were manufactured.

2. Evaluation

Using the gears obtained in each Example and Comparative Example as input gears, the gear unit shown in FIG. 6 and the like was produced. Then, the other end of the string having a weight of 200 g attached to one end was fixed to the output shaft of the gear unit, and the operation of winding the string around the output shaft was repeated.

Then, when the winding operation was performed 300,000 times, the number of damaged gears was confirmed, and the wear resistance (durability) was evaluated according to the following evaluation criteria.

[Evaluation criteria]

A: 0 pieces

B: 1 or more and 5 or less

C: 6 or more and 10 or less

D: 11 or more, 20 or less

E: 21 or more

The results are shown in Table 1.

As shown in Table 1, the gears obtained in each example were excellent in wear resistance. This effect could be further improved by adjusting the amount of clay mineral (talc).

On the other hand, the gear obtained in the comparative example was inferior in wear resistance.

1 Gear unit 2 Casing 3 Input part 4 1st rotary assembly 5 1st internal gear 51 teeth 6 2nd rotary assembly 7 2nd internal gear 71 teeth 8 Input shaft 80 Motor 9 Output shaft 31 2nd input shaft 33 Input gear 331 tooth 41 1st rotating shaft member 42 1st planetary carrier 43 1st planetary shaft member 44 1st planetary gear 441 tooth 45 sun gear 451 tooth 61 2nd rotating member 62 2nd planetary carrier 63 2nd planetary shaft member 64 2nd Planetary gear 641 Tooth J1 Central axis J2 1st planetary axis J3 2nd planetary axis 10 Small head-up display (HUD) 11a Case body 11b Top plate 12 frame 12a Wall plate 12b Upper flange 12c Lower flange 13 Guide shaft 14 Unit case Lead screw 16 Motor 17 Gear (gear) 18 Gear (gear) 19 Nut 20, 21, 22 Bearing 110 Rotating shaft 111 Base 111a Screw 112 Combiner holder 113 Combiner 114 Pinion gear 115 Helical gear 116 Motor 117 Warm gear

Claims (10)

1. 
   A small gear with a module of 0.2 mm or less
   
   It is composed of a resin composition containing a crystalline resin and a clay mineral.
   
   A small gear characterized in that the amount of the clay mineral contained in the resin composition is 5 to 20% by mass.
   
2. 
   The small gear according to claim 1, wherein the crystalline resin is polyamide.
   
3. 
   The small gear according to claim 2, wherein the polyamide is a semi-aromatic polyamide.
   
4. 
   The small gear according to any one of claims 1 to 3, wherein the clay mineral has a flat plate shape.
   
5. 
   The small gear according to claim 4, wherein the clay mineral is talc.
   
6. 
   The small gear according to any one of claims 1 to 5, wherein the resin composition further contains at least one lubricant of an olefin resin-based lubricant and a fluororesin-based lubricant.
   
7. 
   The small gear according to claim 6, wherein the amount of the lubricant contained in the resin composition is 1 to 10% by mass.
   
8. 
   The small gear according to any one of claims 1 to 7, wherein the amount of the inorganic fiber contained in the resin composition is less than 1% by mass.
   
9. 
   A gear unit having the small gear according to any one of claims 1 to 8.
   
10. 
    The gear unit is arranged in the casing, a casing having a central axis, a first internal gear and a second internal gear arranged apart from each other on the inner peripheral surface of the casing in a direction along the central axis. , An input gear that rotates about the central axis, a first rotation assembly that transmits rotational force to and from the input gear, and a second rotation that weakens and transmits rotational force to and from the first rotational assembly. Has an assembly and
    
    The first rotary assembly is arranged between the first internal gear and the input gear in the circumferential direction of the input gear, and the outer peripheral teeth are the inner peripheral teeth of the first internal gear and the outer peripheral teeth of the input gear. A plurality of first planetary gears that mesh with each other, a first planetary carrier that rotatably supports each of the plurality of first planetary gears about a first planetary axis oriented in a direction along the central axis, and the first planetary carrier. A first rotating shaft portion connected to a planetary carrier and having the central axis located at the center thereof, and a sun gear that rotates with the first rotating shaft portion about the central axis, the first planetary carrier and the first rotating shaft portion. One rotating shaft and the sun gear are a single gear member.
    
    The second rotary assembly is arranged between the second internal gear and the sun gear in the circumferential direction of the sun gear, and the outer peripheral teeth are the inner peripheral teeth of the second internal gear and the outer peripheral teeth of the sun gear. A plurality of second planetary gears that mesh with each other, a second planetary carrier that rotatably supports each of the plurality of second planetary gears about a second planetary axis oriented in a direction along the central axis, and the second planetary carrier. It is connected to a planetary carrier and has a second rotation shaft portion whose central axis is located at the center.
    
    The gear unit according to claim 9, wherein at least one of the gear member, the plurality of first planetary gears, the plurality of second planetary gears, and the input gear is composed of the small gear.
    
    
    
    

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