Gear with oil-containing member, and direct-acting actuator

Abstract

To provide a gear capable of being used at a load equivalent to a load on a gear made of a normal metallic material, in spite of a self-lubricating gear.SOLUTION: A gear with an oil-containing member includes a metal gear body 9, a recessed groove part 13 that is formed in a part of a tooth root 11 of the gear body 9, and the oil-containing member 15 that is incorporated into the recessed groove part 13. The recessed groove part 13 has a dovetail groove shape that is continuously provided in a depressed manner in a tooth width direction W from one end surface 11b of a tooth 11 to the other end surface 11c. The oil-containing member 15 has a dovetail tenon shape for being insertion-connected to the recessed groove part 13.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an improvement in a gear with an oil-retaining member, and more particularly to an improvement in a self-lubricating gear. [Background technology]

[0002] BACKGROUND ART Conventionally, a gear disclosed in Patent Document 1 is used in transmissions and the like. The gear disclosed in Patent Document 1 is molded from an oil-impregnated resin material, and does not use a liquid lubricant, thereby preventing the lubricant from leaking out.

[0003] However, the gear disclosed in Patent Document 1 is configured so as not to transmit power because the entire gear is made of an oil-impregnated resin material. This poses the problem of requiring separate gears for transmitting power, bearings to hold them, and space. Furthermore, if surface flaking occurs due to slippage at the base of the teeth, the flaked metal pieces may remain on the tooth surface without being washed away by lubricating oil, potentially leading to further damage such as abrasive wear.

[0004] Similarly, gears made of self-lubricating resin materials, as in Patent Document 2, have a lower maximum usable surface pressure than gears made of metal materials, and therefore require larger gears to be used under the same load as metal materials. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-070855 [Patent Document 2] Japanese Patent Application Publication No. 2019-085487 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention was made to solve the problems associated with the prior art, and its object is to provide a self-lubricating gear that can be used under the same load as gears made of ordinary metal materials. [Means for solving the problem]

[0007] To achieve this object, the first aspect of the present invention provides a gear body made of metal, a recessed groove formed in a part of the tooth base of the gear body; an oil-retaining member incorporated in the recessed groove portion,

[0008] The second invention is a gear with an oil-retaining member according to the first invention, characterized in that the part of the tooth base extends from any position from the tooth bottom to the start of meshing at the tooth base to any position in the meshing portion where two pairs of teeth mesh on the tooth base side.

[0009] The third aspect of the present invention is the gear tooth according to the second aspect of the present invention, wherein the groove portion has a dovetail shape that is continuously recessed in a tooth width direction from one end surface to the other end surface of the tooth, The gear with an oil-retaining member is characterized in that the oil-retaining member has a dovetail shape that is inserted and joined from one end face side of the recessed groove portion.

[0010] A fourth aspect of the present invention is the gear with an oil-retaining member according to the third aspect of the present invention, characterized in that the oil-retaining member has a retaining portion in the tooth width direction.

[0011] A fifth aspect of the present invention is the gear with oil-retaining member according to the fourth aspect of the present invention, characterized in that the retaining portion is provided for each oil-retaining member for one tooth.

[0012] A sixth aspect of the present invention is the gear with oil-retaining member according to the fourth aspect of the present invention, characterized in that the retaining portion is provided integrally over the oil-retaining members of all the teeth.

[0013] The seventh aspect of the present invention is a linear motion actuator incorporating the gear with oil-retaining member according to any one of the first to sixth aspects of the present invention. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a self-lubricating gear that can be used under the same load as a gear made of a normal metallic material. According to the gears of the present invention, when the gears rotate and the tooth bases mesh, and the tooth tips of the gears come into contact with the oil-retaining members, lubricating oil is supplied from the oil-retaining members. When the tooth bases come into contact, two pairs of teeth are generally in mesh, so the surface pressure is lower than near the pitch circumference where only one pair of teeth is in mesh. Even if an oil-retaining member is used, which has a maximum surface pressure about half that of a metal gear material, it can be used even under high loads like gears made of metal gear materials. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a front view showing a state in which a spur gear is employed as a first embodiment of an oil-retaining member-equipped gear of the present invention, and two spur gears are meshed together. FIG. [Figure 2] FIG. 2 is a partially enlarged front view of the area surrounded by the dashed line in FIG. [Figure 3] FIG. 1 is a perspective view of a spur gear according to a first embodiment. [Figure 4] FIG. 4 is a partially enlarged front view of the area surrounded by the dashed line in FIG. 3. [Figure 5] FIG. 10 is a perspective view of a helical gear according to a second embodiment. [Figure 6] FIG. 10 is a perspective view of a double helical gear according to a third embodiment. [Figure 7] FIG. 10 is a perspective view of a fourth embodiment having a retaining portion. [Figure 8] FIG. 8 is an enlarged cross-sectional view of a portion taken along line VIII-VIII in FIG. 7. [Figure 9] FIG. 10 is a perspective view of a fifth embodiment having a retaining portion. [Figure 10] FIG. 10 is an enlarged cross-sectional view of a portion taken along the line XX in FIG. 9. [Figure 11] FIG. 10 is a perspective view of a sixth embodiment having a retaining portion. [Figure 12] FIG. 12 is a partially enlarged front view of the area surrounded by the dashed line in FIG. [Figure 13] (a) is a schematic enlarged partial view showing the state in which the teeth are in contact with the surface of the oil-retaining member when it is first used, (b) is a schematic enlarged partial view showing the state in which the surface of the oil-retaining member has worn down and become flat due to frequent use, and (c) is a schematic enlarged partial view showing the state in which the teeth are in contact with the surface of the oil-retaining member in the state shown in (b). [Figure 14] 1 is a partially cutaway schematic view showing an example of a linear motion actuator incorporating an oil-retaining member-equipped gear according to a first embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] An embodiment of the present invention will be described below. Note that this embodiment is merely one embodiment of the present invention and should not be construed as being limited in any way, and appropriate design modifications are possible within the scope of the present invention. "First embodiment"

[0017] Figures 1 to 4 show an embodiment of the gear with oil-retaining member of the present invention, which is applied to a spur gear. Figure 14 is a schematic diagram, partly cut away, showing an embodiment in which the gear of this embodiment is used in a linear actuator.

[0018] The linear motion actuator is configured to include, for example, a first rotating shaft 3 connected to a motor (not shown) within the housing 1, a first gear 7a (7) connected to the tip of the first rotating shaft 3, a second rotating shaft 5 rotatably held within the housing 1, a second gear 7b (7) connected to the tip of the second rotating shaft 5 and meshing with the first gear 7a (7), a feed screw (not shown) provided on the outer periphery of the second rotating shaft 5, and a nut (not shown) that converts the rotational motion of the feed screw into linear motion and moves linearly (see Figures 1, 2 and 14).

[0019] In this embodiment, the first gear 7a and the second gear 7b are employed as the gear with oil-retaining member 7 of the present invention (see FIGS. 1 and 2), and will be described in detail below. In addition, the configuration of a linear actuator other than the gear with oil-retaining member 7 is well known, so detailed description thereof will be omitted. Furthermore, the linear actuator is not limited to the configuration of this embodiment, and can be appropriately modified in design within the scope of the present invention.

[0020] The gear 7 with oil-retaining member is composed of a gear body 9 made of a metal material for gears, a groove portion (oil-retaining member assembly groove portion) 13 in which a portion (a specified area) of the tooth base 11a of each tooth 11 of the gear body 9 is recessed, and an oil-retaining member 15 assembled into the groove portion 13. The gear body 9 is characterized in that a recessed groove 13 is provided in the tooth base 11a, but the rest of the structure is well known.

[0021] The groove 13 extends from one end face 11b to the other end face 11c of the tooth 11 in the tooth width direction (the direction indicated by the arrow W in FIGS. 3 and 4), and is composed of left and right grooves 13-1 and 13-2, each of which has openings 13a facing a part of the tooth base 11a, i.e., parts of the left and right side faces 11d of the tooth base 11a. The grooves 13-1 and 13-2 open to the one end face 11b and the other end face 11c, as well as to the left and right side faces 13c of the tooth 11, respectively. A part of the side surface 11d of the tooth base 11a extends from any position from the tooth bottom 11e to the start of meshing of the tooth base 11a to any position of the meshing portion where two pairs of teeth mesh on the tooth base 11a side.

[0022] In this embodiment, the recessed groove portion 13 is recessed in a so-called dovetail shape (see FIG. 4). The dovetail shape of groove portion 13 will be explained below. It has a generally trapezoidal cross section, with bottom wall surface 13b and left and right side wall surfaces 13c, 13c that approach each other as they approach opening 13a from bottom wall surface 13b. Groove portion 13 is configured in this dovetail shape in order to prevent oil-retaining member 15, which is installed therein, from slipping out in the tooth thickness direction (the direction indicated by arrow T in FIG. 4).

[0023] The oil-retaining members 15 (15-1, 15-2) are formed in a shape that allows them to be inserted into the recessed groove portion 13 over the entire area and coupled together. In this embodiment, the oil-retaining member 15 is formed in a so-called dovetail shape, which is composed of a first end face 15a that contacts the bottom wall surface 13b of the groove portion 13, a second end face 15b that faces flush with the side surface 11d of the tooth 11 from the opening 13a of the groove portion 13, and left and right third end faces 15c / 15c that become closer as they approach the second end face 15b from the first end face 15a and contact the side wall surfaces 13c / 13c of the groove portion 13. In this embodiment, a clearance fit is adopted so that the connector is fitted into the recessed groove portion 13 with a gap. In addition, the oil-retaining member 15 can be formed larger than the groove portion 13 in an uncompressed state so that it is in close contact with the entire area within the groove portion 13, and an interference fit can be used to insert it in a crushed, compressed state from the opening end of the groove on one end face 11b of the tooth 11 and press-fit it together.

[0024] In this embodiment, the groove portion 13 and the oil-retaining member 15 may have a structure that can prevent the oil-retaining member 15 from coming loose in the tooth thickness direction (W). For example, although not shown, the oil-retaining member may be formed in an arrowhead-shaped sickle tenon shape, and the oil-retaining member may be formed in an arrowhead-shaped groove portion into which the sickle tenon-shaped oil-retaining member can be inserted and connected. Design changes can be made within the scope of the present invention.

[0025] The oil-retaining member 15 may be, for example, made of the following lubricating composition. The lubricating composition is based on ultra-high molecular weight polyethylene or a mixture of ultra-high molecular weight polyethylene and a diallyl phthalate monomer, and can also contain a highly oil-absorbent polymer in order to improve the amount and retention of lubricating oil or grease.

[0026] Highly oil-absorbent polymers are polymers that have the property of trapping oil between their molecules (adsorption-type oil absorbents), or, when in fibrous form, absorbing and retaining oil between the fibers through capillary action (storage-type oil absorbents).Specific substance names include polypropylene, polystyrene, polyurethane, acrylic resins such as polymethacrylate ester, and polynorbornene. In the lubricating composition of the present invention, these highly oil-absorbing polymers may be used alone or in combination, and when used in combination, the amount of lubricating oil or grease retained in the lubricating composition can be freely adjusted by changing the combination and mixing ratio.

[0027] Suitable lubricating oils include, for example, alkyl phenyl ether oils such as octadecyl diphenyl ether, alkyl naphthalene oils such as eicosyl naphthalene, mineral oils, and poly-α-olefin oils. Instead of lubricating oil, a grease based on lubricating oil can be used. In this case, for example, a suitable amount of a known metal soap such as lithium soap, a urea compound, or bentonite is added as a thickener to the lubricating oil. Furthermore, in the present invention, a diallyl phthalate-based monomer can be mixed with the ultra-high molecular weight polyethylene. Specifically, this diallyl phthalate-based monomer is a diallyl phthalate, diallyl isophthalate, or diallyl terephthalate monomer, or a mixture of two or more of these monomers.

[0028] According to this embodiment, when the gear 7 rotates and the tooth base 11a and tooth tip 11e of the meshing tooth 11 come into contact with each other and slide against the oil-retaining member 15 facing the side surface 11d of the tooth base 11a, the lubricant in the oil-retaining member 15 seeps out from the side surface 11d of the gear due to capillary action and is supplied to the meshing surface of the gear 11. Furthermore, as shown in Figure 13, when the oil-retaining member 15 wears down and becomes flat due to frequency of use (see Figure 13(b)), the contact area between the oil-retaining member 15 and the side surface 11d of the gear 11 increases (see Figures 13(a) and (c)), making it easier for the lubricant to seep out of the oil-retaining member 15. However, the amount of lubricant held by the oil-retaining member 15 is reduced compared to when the gear was first used, and so the rate at which the lubricant seeps out per unit area from the oil-retaining member 15 is reduced. This offsets the increase in contact area, and there is no significant change in the amount of lubricant supplied from the oil-retaining member 15, maintaining a state in which an appropriate amount of lubricant necessary and sufficient for lubrication is supplied to the meshing surfaces of the gears. When the tooth base 11a comes into contact, it is generally in a state of two pairs of meshing, so the surface pressure applied is lower (about half) compared to near the pitch circumference where one pair of meshing occurs. Therefore, even if the oil-retaining member 15 of this embodiment, which has a lower maximum surface pressure compared to metal gear materials, is used, it can be used even in cases where high loads are applied, such as in gears made entirely of metal gear materials. Second Embodiment

[0029] FIG. 5 shows a second embodiment of the gear with oil-retaining member according to the present invention, which is applied to a helical gear. The gear 7 with oil-retaining member of this embodiment has a configuration in which, like the first embodiment, a dovetail-shaped groove 13 and a dovetail-shaped oil-retaining member 15 inserted into the groove 13 and assembled with a clearance fit are provided on the side surface 11d of the tooth base 11a region of the gear body 9 of a helical gear made of a metallic gear material. The gear body 9 has a well-known configuration. The groove portion 13 and the oil-retaining member 15 are similar in configuration to those of the first embodiment, and therefore a description thereof will be omitted. Furthermore, the effects of this embodiment are the same as those described in the first embodiment, and therefore a description thereof will be omitted. "Third embodiment"

[0030] FIG. 6 shows a third embodiment of the gear with oil-retaining member according to the present invention, which is applied to a double-helical gear. The gear 7 with oil-retaining member of this embodiment has a configuration in which, like the first embodiment, a dovetail-shaped groove 13 and a dovetail-shaped oil-retaining member 15 inserted into the groove 13 and assembled with a clearance fit are provided on the side surface 11d of the tooth base 11a region of the gear body 9 of a helical gear made of a metallic gear material. The gear body 9 has a well-known configuration. The groove portion 13 and the oil-retaining member 15 are similar in configuration to those of the first embodiment, and therefore a description thereof will be omitted. Furthermore, the effects of the helical gear of this embodiment are the same as those described in the first embodiment, and therefore a description thereof will be omitted. "Fourth Embodiment"

[0031] Figures 7 and 8 show a fourth embodiment of a gear with an oil-retaining member, which is an embodiment in which the present invention is applied to a spur gear. This embodiment is characterized in that each tooth 11 is provided with a retaining portion 21 that prevents the oil-retaining member 15 from slipping out in the tooth width (W) direction. The configuration and effects other than the structure in which the oil-retaining member 15 is provided with the retaining portion 21 are the same as those of the first embodiment, and therefore a description thereof will be omitted.

[0032] The groove portion 13 of this embodiment is composed of left and right groove portions 13-1 and 13-2 formed in the same manner as in the first embodiment, and a groove portion 13-3 formed continuously in one end face 11b of the tooth 11. The groove portion 13-3 is formed in the same dovetail shape as the groove portions 13-1 (13-2).

[0033] The oil-impregnated member 15 of this embodiment is formed in the same manner as in the first embodiment, and is formed in a U-shape by dovetail-shaped oil-impregnated members 15-1 and 15-2 that are fitted into the left and right grooves 13-1 and 13-2, and by bridging the ends of the oil-impregnated members 15-1 and 15-2 that face one end face 11b together, and by forming the same oil-impregnated member 15-3 as the oil-impregnated member 15-1 (15-2) and also by dovetail-shaped oil-impregnated member 15-3 that is fitted into groove 13-3. Like 15-1 (15-2), the oil-impregnated member 15-3 is fitted into groove 13-3 with a loose fit. In this embodiment, the oil-retaining member 15-3 functions as a retaining portion 21 in the tooth width direction W.

[0034] In this embodiment, the retaining portion 21 is made up of an oil-retaining member 15-3 and a rectangular plate-shaped protruding portion 23 that protrudes from the upper end of the oil-retaining member 15-3 in the tooth width direction W by a predetermined height. The protrusion 23 is integrally molded from the same lubricating composition as the oil-retaining member 15. The shape of the protrusion 23 is not particularly limited to the illustrated form. Furthermore, the protrusions 23 may be formed separately from the respective oil-retaining members 15-3 and then integrated with the top surfaces of the respective oil-retaining members 15-3 by adhesion or the like, which is within the scope of the present invention. In this case, the material of the protrusions 23 does not have to be the same as that of the oil-retaining members 15-3.

[0035] Therefore, according to this embodiment, the groove portion 13-3 and the oil-retaining member 15-3 are provided, which function as a retaining portion 21 in the tooth width direction W, and therefore, in addition to the retaining function in the tooth thickness direction T provided by the groove portions 13-1, 13-2 and the oil-retaining members 15-1, 15-2, the oil-retaining member 15 can be reliably retained. Furthermore, according to this embodiment, the protrusion 23 made of the same lubricating composition as the oil-containing member 15-3 is provided integrally as the oil-containing member 15, so that lubricant can also be supplied from the oil-containing member 15-3 to the oil-containing members 15-1 and 15-2.

[0036] It is of course possible to apply the oil-retaining member and groove portion equipped with the anti-slip structure of this embodiment to the helical gear of the second embodiment and the double-helical gear of the third embodiment, and this is within the scope of the present invention. Fifth Embodiment

[0037] Figures 9 and 10 show a fifth embodiment of a gear with an oil-retaining member according to the present invention, which is an embodiment in which the present invention is applied to a spur gear. This embodiment is characterized in that it is provided with a retaining portion 25 in the tooth width (W) direction of the oil-retaining member 15 across all teeth 11. The configuration and effects other than the structure in which the oil-retaining member 15 is provided with the retaining portion 25 are the same as those of the gear of the first embodiment, and therefore a description thereof will be omitted. The configurations and effects of the recessed groove portion 13-3 and the oil-retaining member 15-3 are the same as those of the fourth embodiment.

[0038] The retaining portion 25 is made up of an oil-retaining member 15-3 fitted into the recessed groove 13-3 of each tooth 11, and an annular protrusion 27 integrally provided across the top surface of each oil-retaining member 15-3. The protruding height and the outer and inner diameters of the protruding portion 27 are not particularly limited and can be appropriately changed in design depending on the specifications. Furthermore, the protrusions 27 may be formed separately from the respective oil-retaining members 15-3 and then integrated with the top surfaces of the respective oil-retaining members 15-3 by adhesion or the like, and this is within the scope of the present invention. In this case, the material of the protrusions 27 does not have to be the same as that of the oil-retaining members 15-3.

[0039] Therefore, according to this embodiment, the groove portion 13-3 and the oil-retaining member 15-3 are provided, which function as a retaining portion 25 in the tooth width direction W, and therefore, in addition to the retaining function in the tooth thickness direction T provided by the groove portions 13-1, 13-2 and the oil-retaining members 15-1, 15-2, the oil-retaining member 15 can be reliably retained. Furthermore, according to this embodiment, the protrusion 25 made of the same lubricating composition as the oil-containing member 15-3 is provided integrally as the oil-containing member 15, so that lubricant can also be supplied from the oil-containing member 15-3 to the oil-containing members 15-1 and 15-2.

[0040] It is of course possible to apply the oil-retaining member and groove portion equipped with the anti-slip structure of this embodiment to the helical gear of the second embodiment and the double-helical gear of the third embodiment, and this is within the scope of the present invention. "Sixth Embodiment"

[0041] Figures 11 and 12 show a sixth embodiment of a gear with an oil-retaining member according to the present invention, which is an embodiment in which the present invention is applied to a spur gear, and the configuration of the groove portion 13 and the oil-retaining member 15 differs from that of the first embodiment. The configuration other than the fact that the oil-retaining member 15 has a retaining structure is the same as that of the gear of the first embodiment, and therefore a description thereof will be omitted.

[0042] In this embodiment, grooves 13-1 (13) and 13-2 (13) are recessed in the tooth width direction W on the left and right side surfaces 13d, 13d of the root 11a of each tooth 11. The grooves 13-1 and 13-2 open to the left and right side surfaces 13d, 13d of the tooth 11, respectively, and to one end surface 11b and the other end surface 11c. The openings of the grooves 13-1 and 13-2 on the one end surface 11b extend toward one end surface 9a of the gear body 9. A tooth bottom-side groove 13-4 is recessed parallel to the tooth bottom 11e on one end face 9a of the gear body 9 near the tooth bottom 11e between circumferentially adjacent teeth 11. This tooth bottom-side groove 13-4 is continuous with the groove 13-1 of the tooth 11 and the groove 13-2 of the tooth 11 adjacent to that tooth 11, and is recessed in a modified U-shape in plan view. The groove shape of the recessed groove portions 13 (13-1, 13-2, 13-4) is assumed to be a dovetail groove shape, similar to the first embodiment.

[0043] The oil-impregnated member 15 is composed of oil-impregnated members 15-1 and 15-2 that are fitted into the grooves 13-1 and 13-2, and an oil-impregnated member 15-4 that is fitted into the groove 13-4. The oil-impregnated members 15-1, 15-2, and 15-4 are integrally molded from the same material into a deformed U-shape in plan view that is fitted over the entire area of ​​the grooves 13-1, 13-2, and 13-4. The oil-impregnated members 15 (15-1, 15-2, and 15-4) are assumed to have a dovetail shape made of a lubricating composition, as in the first embodiment. In this embodiment, the oil-retaining member 15-4 functions as a retaining portion 29 in the tooth width direction W.

[0044] Therefore, according to this embodiment, the groove portion 13-4 and the oil-retaining member 15-4 are provided, which function as anti-slip portions 29 in the tooth width direction W, and therefore, in addition to the anti-slip function in the tooth thickness direction T provided by the groove portions 13-1, 13-2 and the oil-retaining members 15-1, 15-2, the oil-retaining member 15 can also exhibit a reliable anti-slip function. Furthermore, according to this embodiment, the oil-containing member 15-4 and the oil-containing members 15-1 and 15-2 are integrally provided with the same lubricating composition, so that the lubricant can be supplied from the oil-containing member 15-4 to the oil-containing members 15-1 and 15-2.

[0045] It is of course possible to apply the oil-retaining member and groove portion equipped with the anti-slip structure of this embodiment to the helical gear of the second embodiment and the double-helical gear of the third embodiment, and this is within the scope of the present invention. Other Embodiments

[0046] The configurations of the above embodiments can also be applied to bevel gears (straight bevel gears, spiral bevel gears) and are within the scope of the present invention. Furthermore, the gear with an oil-retaining member according to each of the above-described embodiments can be used in all devices that have a gear mechanism, such as actuators, reducers, transmissions, industrial machinery, and home appliances. [Industrial Applicability]

[0047] The present invention can be applied to gears in general. [Explanation of symbols]

[0048] 1. Housing 3 First rotating shaft 5 Second rotating shaft 7 Gears with oil-impregnated parts 9 Gear body 11 teeth 11a Root 11b One end face 11c Other end surface 11d side 11e Root 13 Concave groove part 15 Oil-impregnated parts 21 Stopper 25 Retaining part 29 Retaining part T Tooth thickness direction W Face width direction

Claims

1. A metal gear body, a recessed groove formed in a part of the tooth base of the gear body; an oil-retaining member incorporated in the recessed groove portion.

2. 2. A gear with an oil-retaining member according to claim 1, characterized in that the part of the tooth base extends from any position from the tooth bottom to the start of meshing of the tooth base to any position of the meshing portion where two pairs of teeth mesh on the tooth base side.

3. The groove portion has a dovetail shape that is continuously recessed in the tooth width direction from one end surface to the other end surface of the tooth, 3. The gear with an oil-retaining member according to claim 2, wherein the oil-retaining member has a dovetail shape that is inserted and joined from one end face side of the recessed groove portion.

4. 4. A gear with an oil-retaining member according to claim 3, wherein the oil-retaining member has a retaining portion in the tooth width direction.

5. 5. The gear with oil-retaining member according to claim 4, wherein the retaining portion is provided for each oil-retaining member for one tooth.

6. 5. A gear with an oil-retaining member according to claim 4, wherein the retaining portion is integrally provided over all of the oil-retaining members of the gear teeth.

7. A linear motion actuator incorporating the gear with oil-retaining member according to any one of claims 1 to 6.

Images