JP2015078728A - Roller pinion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a roller pinion device 1 capable of maintaining a sufficient engagement state of a pin 1a to a rack 2 for a long time by improvement of lubricity and abrasion resistance, capable of improving durability, and capable of contributing to the long service life.SOLUTION: A porous metal-plated layer 11 high in hardness is applied to the entire peripheral surface of a pin 1a, abrasion resistance of the pin 1a to a rack 2 is improved, and lubricating oil is filled in a small pore 1c of the porous metal-plated layer 11 and a fine pore 12 of the pin 1a, and therefore, lubricity of the pin 1a to the rack 2 is improved. That is, in rotational driving of a roller pinion device 1, a load is applied to a roller pinion 1A, and in accordance with slidably contacting and separating of the pin 1a to and from a tooth part 2a of the rack, the lubricating oil goes in and out of the fine pore 12 and the small pore 1c like respiration, and therefore, lubricity of the pin 1a to the rack 2 is excellent.

Description

  The present invention relates to a roller pinion composed of a plurality of pins engaged with a tooth portion of a rack, and more particularly to a roller pinion device improved so as to improve the lubricity and wear resistance of the pins with respect to the rack.

As an operation mechanism that combines a rack and a pinion, there is one known as a “rotational motion / linear motion conversion device” (see, for example, Patent Document 1).
The conversion device of Patent Document 1 configures a roller pinion in which a plurality of pins are provided between two roller holding members. The pin of the roller pinion meshes with the rack, and the rack reciprocates in the longitudinal direction as the roller pinion rotates. As a result, a rack and pinion that has low noise, low vibration, low transmission resistance, no rattling, and high rigidity has been put into practical use.
This type of conversion device has been greatly improved by incorporating the rack and pinion into a machine tool, a precision drive mechanism, traveling of the robot in a clean room, stocker transport, cleaning line transport, and the like.

  In Patent Document 2, a bearing provided with a thrust bearing that slides with the tip of the shaft abutting is configured, and a thrust bearing is made of ultrahigh molecular weight polyethylene that can be injection-molded (SIX-8000 manufactured by Polyhisorijoule Japan). To increase the durability of the sliding portion that receives a thrust load.

  Patent Document 3 discloses a bearing device provided with a bearing plate to receive a load in the thrust direction of the shaft. The bearing plate is made of an alloy of a general-purpose resin having a low melting point and a heat-resistant resin having a high melting point. General-purpose resin supports the load in the thrust direction, and heat-resistant resin works as a lubricant for the bearing plate by melting to prevent wear.

  Patent Document 4 discloses a bearing device having a resin thrust receiver and a metal plate that are wear resistant and have a stable coefficient of friction. A frictional force is generated at the contact surface between the resin thrust receiver and the metal plate to obtain a braking force for preventing the window from falling as a reverse rotation preventing force.

  Patent Document 5 discloses a bearing structure including a thrust ball, a plate, and a high hardness thrust receiving plate. It is configured to maintain a contact state in contact with the plate and the thrust receiving plate at one point of the thrust ball, to prevent wear at the contact portion and to ensure durability.

  Patent Document 6 discloses a thrust bearing structure in which a ball receiving groove is formed in a motor shaft, and a steel ball is arranged in the ball receiving groove. The steel ball is configured to make point contact with the quenched plate, and suppresses friction of a sliding portion provided between the steel ball and the plate.

  Patent Document 7 relates to a thrust bearing incorporated in a generator or a pump, and discloses a thrust bearing sliding member improved so as to withstand high surface pressure under severe conditions as the size is reduced. Yes. As a representative example thereof, a sliding member for a thrust bearing, which has a polyether-etherketone base material and is excellent in wear resistance and has a low starting friction coefficient, is disclosed.

JP-A-10-184842 JP 2000-205243 A JP-A-5-68355 JP-A-9-191609 JP 2002-155930 A Japanese Patent Laid-Open No. 3-181610 JP 9-316323 A

In any of the above Patent Documents 1-7, the contact structure of the shaft and the rotating shaft is improved so that the thrust bearing is excellent in slidability, lubricity and wear resistance.
However, the lubricity and wear resistance when the pin of the roller pinion meshes with the teeth of the rack are hardly considered, so there is room for improvement in this direction.

  The present invention has been made in view of the above circumstances. The object of the present invention is to improve the lubricity of the pins with respect to the rack and facilitate maintenance, inspection and management when the pins are engaged with the rack and rotated. At the same time, it is an object of the present invention to provide a roller pinion device that has improved wear resistance, can maintain a good meshing state of pins with a rack over a long period of time, and has improved durability and extended life.

(About claim 1)
In the roller pinion device, the first holding member and the second holding member have a plurality of mounting holes formed along a certain circumference and are juxtaposed in a state of facing each other. The first bearing is fitted into the mounting hole of the first holding member, and the second bearing is fitted into the mounting hole of the second holding member.
The plurality of pins are arranged to mesh with a rack having a large number of teeth, one end of the pin is rotatably inserted and supported by the first bearing of the first holding member, and the other end of the second holding member. The second bearing is rotatably inserted and supported.
The first bearing and the second bearing have a cylindrical casing having a sliding body that is fitted into the outer peripheral portion of the pin and rotatably held in a circumscribed state with the pin, and closes the outer opening of the casing. A cover plate is provided.
The pin has a fine hole surface portion formed over the entire peripheral surface and having a large number of fine holes, and a high-hardness porous metal plating layer formed on the entire surface of the fine hole surface portion so as to cover the fine hole surface portion. .
The fine pores and porous metal plating layer are filled with lubricating oil inside, and the lubricating oil is gradually removed from the small holes as fine gap space between the fine pores and porous metal plating layer. A lubricating oil film is formed on the tooth portion of the rack that oozes on the outer surface of the rack and meshes with the pins.

According to the first aspect of the present invention, since the high-hardness porous metal plating layer is provided on the entire peripheral surface of the pin, the wear resistance of the pin with respect to the rack is improved.
Since the lubricating oil is filled and held in the fine holes of the porous metal plating layer and the small holes of the pins, the lubricity of the pins with respect to the teeth of the rack is improved.

That is, when the roller pinion rotates, as the pin slides away from the rack, the lubricating oil goes in and out of the small holes and the fine holes as in the breathing action, thereby improving the lubricity of the pins with respect to the rack. It is.
As lubrication oil enters and exits the small and fine holes, it is not necessary to periodically lubricate the racks and pins, so an oil-free system is built, making maintenance, inspection and management of the roller pinion easy. Become.

The improvement in lubricity and the improvement in wear resistance makes it possible to maintain a good engagement state of the pins with the rack over a long period of time, improving durability and extending the life.
In addition, when the pinion wear resistance is improved, the amount of wear powder generated when the pin meshes with the rack is reduced and the roller pinion is used with the rack in a clean room where a clean air environment is required. Is preferred.

(About claim 2)
The thickness of the porous metal plating layer is in the range of 10 μm to 300 μm, and the diameter of the small holes in the porous metal plating layer is 100 μm or less.
According to the second aspect, the porous metal plating layer can be filled and held with sufficient lubricating oil, which contributes to the improvement of the lubricity of the pins with respect to the rack.

(Claim 3)
The porous metal plating layer is a plating layer made of one of hard chromium, nickel-chromium alloy, rhodium and platinum having a Vickers hardness (Hv) of 850 or more.
In Claim 3, since the Vickers hardness (Hv) of the porous metal plating layer is set to 850 or more, it contributes to the improvement of the wear resistance of the pin with respect to the rack.
.

(Example 1) which is a perspective view which shows the roller pinion apparatus meshing | engaged with a rack. It is a longitudinal cross-sectional view which shows a roller pinion apparatus (Example 1). (A) is a front view showing one end surface 1A, the other end surface 1B, and a circumferential surface 1C of the pin, and (b) is a broken sectional view showing the pin (Example 1). ³ is a graph showing the relationship between the particle size (μm) of wear powder and the cumulative number concentration per unit cube (pieces / m ³ ) (Example 1). (Example 2) which is a longitudinal cross-sectional view which shows a roller pinion. (Example 3) which is a longitudinal cross-sectional view which shows the roller pinion meshing with a spur gear.

  In the roller pinion of the present invention, when the pin meshes with the rack and rotates, the pin lubricity to the rack is improved and the wear resistance is improved. Can be maintained over a long period of time, and the life can be extended.

[Configuration of Example 1]
A first embodiment of the present invention will be described with reference to FIGS. In the following description, unless otherwise specified, the position and direction of each member are specified in the left and right and up and down directions of the corresponding drawings throughout each embodiment.

A roller pinion 1 shown in FIG. 1 meshes with a tooth portion 2a of a rack 2 having a bowl shape, and a plurality of (for example, ten) pins 1a described later are arranged at equal angular intervals. As shown in FIG. 2, the roller pinion 1 </ b> A of the roller pinion device 1 includes a first holding member 3 and a second holding member 4 that are in the form of flange plates that are juxtaposed to face each other. Hereinafter, the roller pinion device 1 and the roller pinion 1A are used in the sense that they have the same structure.
A plurality of attachment holes 3 a corresponding to the pins 1 a are provided along the outer circumference of the first holding member 3, and the outer edge of the second holding member 4 is arranged along the circumference. A plurality of mounting holes 4a corresponding to the pins 1a are provided.

The first needle bearing 5 and the second needle bearing 6 function as a first bearing and a second bearing, respectively. As shown in FIG. 2, a plurality of needle rollers 9 are provided as sliding bodies on a casing 7 as a cage. Installed.
The needle rollers 9 are arranged along a predetermined pitch circle along the housing 7, and are in sliding contact with the pin 1a serving as the center. A cap-shaped cover plate 10 that closes the outer opening 7a is integrally connected to the outer openings 7a of the left and right housings 7 so as to function as a thrust bearing.

  The first needle bearing 5 is fitted into the mounting hole 3 a of the first holding member 3, and the second needle bearing 6 is fitted into the mounting hole 4 a of the second holding member 4. One end 1 e of each pin 1 a is rotatably inserted and supported by the first needle bearing 5 of the first holding member 3, and the other end 1 f is rotatably inserted and supported by the second needle bearing 6 of the second holding member 4. Has been.

In FIG. 3A, the entire outer surface including one end face 10A, the other end face 10B and the circumferential face 10C of the pin 1a is applied as a porous metal plating layer 11 having high hardness by plating.
The porous metal plating layer 11 is made of one selected from hard chromium, nickel-chromium alloy, rhodium, and platinum having a Vikers hardness (Hv) of 850 or more. In this case, hard chrome is selected and applied as an example of the present invention.

In forming the porous metal plating layer 11 as a porous hard chrome plating layer, the pin 1a as a base material is dented, a pear ground or honing is applied, and high-quality chrome plating is applied to the entire peripheral surface of the pin 1a. Or, anodizing is performed after a hard chrome plating so that a reverse current is applied, and after electrolytic etching, honing is performed according to a known processing method (for example, Sanwa Plating Industry Co., Ltd.). The thickness T of the porous metal plating layer 11 is set to a size range of 10 μm to 300 μm, and the diameter d of the small hole 1 c which is a fine gap space of the porous metal plating layer 11 is set to 100 μm or less.
As will be described later, even if the porous metal plating layer 11 is formed after forming the fine holes 12 on the outer peripheral surface of the pin 1a, the porous metal plating layer 11 does not enter the fine holes.

Further, as shown in FIG. 3B, lubricating oil (not shown) is applied to the outer peripheral surface of the pin 1a by electron beam hole processing (for example, refer to the processing method of MPS Corporation, Taiheiyo Special Casting Co., Ltd.). A large number of fine holes 12 for filling and holding are provided. A surface layer portion provided with the fine holes 12 of the pin 1a is used as a fine hole surface portion 12A. The depth direction W of the fine hole 12 is perpendicular to the axial direction S of the pin 1a.
The processing of the fine holes 12 is performed prior to the formation of the porous metal plating layer 11, and the diameter D of the fine holes 12 is set within a dimensional range of 0.1 mm to 0.5 mm, and the depth of the fine holes 12 is set. The thickness E is set within a size range of 0.5 mm to 1.0 mm.
In FIG. 3B, from the viewpoint of convenience, the diameter D of the fine hole 12 of the pin 1a and the diameter d of the small hole 1c communicate with each other. Actually, the fine hole 12 and the small hole 1c may partially communicate with each other due to the difference in diameter, or may be in a discontinuous state in some cases.

In the above configuration, the pin 1a in the first holding member 3 operates in the same manner as the pin 1a in the second holding member 4, and therefore only the pin 1a in the first holding member 3 will be described. When the roller pinion 1 is rotationally driven, the pin 1a of the roller pinion 1 meshes with the tooth portion 2a of the rack 2 and travels in the longitudinal direction K (see FIG. 1).
During this rotational driving process, the micropores 12 and the porous metal plating layer 11 are filled and retained with lubricating oil. The retained lubricating oil is gradually oozed out of the outer surface of the porous metal plating layer 11 from the micro holes 12 and the small holes 1 c serving as the minute gaps between the porous metal plating layer 11. As a result, a lubricating oil film (not shown) having a thickness of a micron is formed on the tooth portion 2a of the rack 2 meshing with the pin 1a.

[Effect of Example 1]
Since the porous hard chrome plating layer is applied as the high-hardness porous metal plating layer 11 to the entire peripheral surface of the pin 1a, the wear resistance of the pin 1a with respect to the rack 2 is improved.
Since the lubricating oil is filled and held in the fine holes 11a of the porous metal plating layer 11 and the small holes 1c of the pins 1a, the lubricity of the pins 1a with respect to the teeth 2a of the rack 2 is improved.

That is, when the roller pinion 1A rotates, as the pin 1a slides away from the rack 2, the lubricating oil itself enters and exits the small hole 1c and the fine hole 12 like a breathing action. This improves the lubricity.
As the lubricating oil enters and exits the small holes 1c and the fine holes 12, it is no longer necessary to periodically lubricate the rack 2 and the pins 1a, so that an oil-free system is constructed and maintenance and inspection for the roller pinion 1A are performed. And management becomes easier.
By improving the lubricity and improving the wear resistance, it is possible to maintain a good meshing state of the pin 1a with the rack 2 over a long period of time, improving durability and extending the life.

Here, the graph of FIG. 4 shows the result of actual measurement of the amount of wear powder generated by the meshing rotation of the pin 1a and the rack 2. This graph shows the relationship between the particle size (μm) of the wear powder and the cumulative number concentration per unit cube (pieces / m ³ ). In Example 1 of the present invention, the broken line indicated by the symbol M in FIG. Indicated by A pin not provided with a porous hard chrome plating layer is indicated by a broken line with a symbol N.
Compared with the broken line of the symbol N, the broken line of the symbol M shows that the wear powder has a very small particle size and the accumulated number concentration is extremely small. For this reason, it has been found that the pin 1a of the present embodiment is suitable when the roller pinion 1 is used together with the rack 2 in a clean room where a clean air environment is required.

The diameter d of the fine hole 12 is set within a dimensional range of 0.1 mm to 0.5 mm, and the depth E of the fine hole 12 is set within a dimensional range of 0.5 mm to 1.0 mm. The pin 1a exhibits a porous characteristic and contributes to improvement of the lubricity of the pin 1a with respect to the rack 2.
Further, in forming the porous metal plating layer 11, hard chromium having a Vickers hardness (Hv) of 850 or more is applied, which contributes to improvement of the wear resistance of the pin 1 a with respect to the rack 2. The same applies when one of nickel-chromium alloy, rhodium and platinum is selected and applied instead of hard chromium.

  The thickness T of the porous metal plating layer 11 is set to a size range of 10 μm to 100 μm, and the diameter D of the small hole 1 c of the porous metal plating layer 11 is set to 100 μm or less. Thereby, the porous metal plating layer 11 can be filled and held with sufficient lubricating oil, which contributes to improvement of the lubricity of the pin 1a with respect to the rack 2.

[Configuration of Example 2]
FIG. 5 shows a second embodiment of the present invention. The difference between the second embodiment and the first embodiment is that the outer opening 7a of the housing 7 is closed using an annular pressing plate 10H instead of the cap-shaped lid plate 10. Even if the presser plate 10H is used as in the eighth embodiment, the same effect as in the first embodiment can be obtained.

[Configuration of Example 3]
FIG. 6 shows a third embodiment of the present invention. The third embodiment differs from the first embodiment in that a spur gear 14 having spur teeth 14 a formed in the circumferential direction N is used in place of the rack 2.
The roller pinion 1 may be disposed horizontally and meshed with the spur gear 14 to drive the output shaft of the indexing device or to rotate the astronomical telescope of the observatory.

[Modification]
(A) In the first embodiment, the rack 2 is arranged horizontally and the roller pinion 1A is engaged with the rack 2 so as to be perpendicular to the rack 2. However, the arrangement direction of the rack 2 and the roller pinion 1A is the use state or the attachment state. It can be set as desired according to the above.
(B) Although the number of pins 1a in the first embodiment is ten, the number of pins 1a is not limited to ten and may be set to a desired number according to the use situation. Moreover, although the cap-shaped cover plate 10 is integrally formed in the outer opening 7a of the housing 7, a separate cap may be joined to the outer opening 7a by welding means or the like.

  In the roller pinion device according to the present invention, it is possible to maintain a good engagement state of the pins with the rack over a long period of time by improving the lubricity and improving the wear resistance, thereby improving the durability and extending the life. Is. It is possible to stimulate the demand of the traders who pay attention to the good operability of the roller pinion and to use it for the machine industry through the distribution of related parts.

DESCRIPTION OF SYMBOLS 1 Roller pinion apparatus 1A Roller pinion 1a Pin 1c Small hole of porous metal plating layer (fine gap space of porous metal plating layer)
1e One end of the pin 1f The other end of the pin 1A One end of the pin 1B The other end of the pin 2 Rack 3 First holding member 3a, 4a Mounting hole 4 Second holding member 5 First needle bearing (first bearing)
6 Second needle bearing (second bearing)
7 Housing 7a Outside opening of housing 9 Needle roller (sliding body)
10 Cap-shaped lid plate 11 Porous metal plating layer (porous hard chrome plating layer)
12 Micro hole 12A Micro hole surface S Pin axial direction W Pin depth direction

Claims (3)

A first holding member and a second holding member which have a plurality of mounting holes formed along a certain circumference and are juxtaposed in a state of facing each other;
A first bearing fitted into the mounting hole of the first holding member and a second bearing fitted into the mounting hole of the second holding member;
One end portion is rotatably inserted and supported by the first bearing of the first holding member, and the other end portion has a plurality of pins rotatably inserted and supported by the second bearing of the second holding member. A roller pinion device comprising a roller pinion meshing with a rack composed of a plurality of teeth,
The first bearing and the second bearing include a cylindrical housing having a sliding body that is fitted in an outer peripheral portion of the pin and is rotatably held in a circumscribed state with the pin, and an outer opening of the housing A lid plate for closing,
The pin is formed over the entire peripheral surface and has a fine hole surface portion having a large number of fine holes, and a high-hardness porous metal plating layer formed on the entire surface of the fine hole surface portion so as to cover the fine hole surface portion. And
The micropores and the porous metal plating layer are filled and held with lubricating oil, and the lubricating oil is gradually supplied from small holes as fine gap spaces between the micropores and the porous metal plating layer. A roller pinion device characterized in that a lubricating oil film is formed on the tooth portion of the rack that oozes onto the outer surface of the porous metal plating layer and meshes with the pin.   2. The roller pinion device according to claim 1, wherein a thickness of the porous metal plating layer is in a size range of 10 μm to 300 μm, and a diameter of the small hole of the porous metal plating layer is 100 μm or less.   The porous metal plating layer is a plating layer made of one of hard chromium, nickel-chromium alloy, rhodium, and platinum having a Vickers hardness (Hv) of 850 or more. Roller pinion device.

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