JP2009222092A - Preload mechanism, four-point contact bearing, rotary device, and light signal transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a preload mechanism suitable for an adequate resin form by miniaturizing and slimming a four-point contact bearing. <P>SOLUTION: The preload mechanism comprises a preload ring 52 for clamping a preload spring 53a in the direction of its coil diameter, and a rotary base 1. A space between the preload ring 52 and the rotary base 1 is smaller than the coil diameter of the preload spring 53a, and the preload ring 52 and the rotary base 1 compress the preload spring 53a in the direction of the coil diameter to generate a preload. The compression of the preload spring 53a in the direction of the coil diameter is utilized for imparting a uniform force of the preload while eliminating the influences of friction between the preload spring 53a and each of the preload ring 52 and the rotary base 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pressurizing mechanism used to generate a pressurization in a four-point contact bearing or the like. The present invention also relates to a four-point contact bearing, a rotating device, and an optical signal transmission device using the pressurizing mechanism.

  2. Description of the Related Art As surveillance camera devices that are attached to an indoor ceiling or the like, those that perform surveillance by controlling the pan angle and tilt angle of a camera to change the imaging direction are widely used. In such a monitoring camera device, a fixed part fixed to a ceiling or the like and a rotating part (movable part) that can rotate in the pan direction are connected via an electric rotating table (head). There are many cases.

  In this case, since the axial load and the radial load act on the connection portion (rotation support portion) between the rotation portion and the fixed portion, rotation support using two sets of single row deep groove bearings is usually performed. (For example, refer to Patent Document 1).

  However, when such a single-row deep groove ball bearing is used, since it is necessary to have a two-row configuration, there is a problem that the size in the axial direction becomes long and it is difficult to reduce the size of the apparatus.

  Thus, it has been proposed to shorten the length in the axial direction by a one-row configuration using a four-point contact bearing (see, for example, Patent Document 2). A four-point contact bearing normally applies an appropriate pressure by pressing an end portion of a divided inner ring or outer ring (hereinafter referred to as a divided inner ring) in the axial direction with a bearing nut or the like. However, in recent years, bearing parts are often made of resin for weight reduction, and in such a case, the linear expansion coefficient of a split inner ring or the like (resin part) increases. Therefore, in the conventional configuration in which the pressure is applied by fixing the position of the split inner ring or the like with the bearing nut, there is a problem that the variation in the pressure due to the temperature change becomes large.

  Therefore, it is conceivable to apply a pressure to the split inner ring or the like using a wave washer. However, since the wave washer applies pressure only at several points in the circumferential direction, if the thickness of the split inner ring or the like is reduced in order to reduce the size (thinning), the split inner ring or the like bends and becomes smooth. There is a problem in that it is not possible to obtain a proper rotational movement. On the other hand, it is conceivable to use an elastic member that can apply pressure over the entire circumference, such as an O-ring, but the rubber constituting the O-ring is subject to elastic deterioration due to permanent compression strain when a load is always applied. Therefore, there is a problem that the pressurization varies with time.

  In addition, a buffer mechanism that uses a tilted oval coil spring in a recumbent state has been proposed (see, for example, Patent Document 3). In this case, the spring is installed in the spring so that the tilted oval coil spring can operate smoothly during tilt deformation. It is necessary to apply a lubricant such as grease or oil to a flange or the like that comes into contact (paragraph 0024 of Patent Document 3). Resin bearings (unlike metal bearings) have the advantage that they can be used without using a lubricant because there is no contact between metals. However, when the above-described inclined oval coil spring is used, the lubricant is not used. There is a problem that it is not possible to take advantage of unnecessary.

JP 2007-201817 A (paragraph 0002, FIG. 6) JP 2003-227516 A (paragraph 0020, FIG. 1) JP 2001-304336 A (paragraph 0005, FIG. 1)

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a pressurizing mechanism that can reduce the size and thickness of a four-point contact bearing and is also suitable for resinization. .

  The preload mechanism according to the present invention includes a coil spring, and first and second support members that sandwich the coil spring in the coil radial direction, and includes the first support member and the second support member. The clearance is smaller than the coil diameter of the coil spring, and the first and second support members generate preload by compressing the coil spring in the direction of the coil diameter.

  According to the present invention, by compressing the coil spring in the coil radial direction, the preload can be applied more uniformly than when the wave washer is used (Patent Document 2), and the coil spring is used in a lying state. In such a case, the influence of friction or the like as in (Patent Document 3) can be eliminated. Therefore, by using this pressurizing mechanism, the four-point contact bearing can be reduced in size and thickness. Moreover, the advantage that a lubricant is unnecessary can be utilized by applying to a resin bearing.

  Hereinafter, the configuration of a rotating device equipped with a four-point contact bearing in each embodiment of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view illustrating a configuration of an optical signal transmission device including a rotation device 100 that employs a four-point contact bearing in the first embodiment. FIG. 2 is an exploded perspective view of the rotating device 100. As shown in FIG. 1, the rotating device 100 includes a fixed base 1a fixed to a ceiling or the like, and a rotating base 1b to which, for example, a camera (imaging means) is attached. The rotation base 1b is supported by the fixed base 1a via the bearing 5 so as to be rotatable, for example, about a vertical rotation axis R. Here, the fixed base 1a and each component mounted thereon are collectively referred to as a “fixed portion”, and the rotating base 1b and each component mounted thereon are collectively referred to as a “rotating portion”.

  A fixed-side core 2a and a rotating-side core 2b for transmitting power are fixed to the fixed base 1a and the rotating base 1b, respectively. The cores 2a and 2b are fixed to the bases 1a and 1b, respectively, so that the center axes thereof are the same as the rotation axis R of the rotating device 100 (that is, the rotation center of the rotation base 1b). Inside the cores 2a and 2b, a fixed-side bobbin 21a and a rotating-side bobbin 21b around which a winding for power transmission is wound are housed.

  On the rotation axis R of the rotating device 100, there are a fixed-side optical element 3a and a rotating-side optical element 3b for transmitting an image signal from a camera (not shown) attached to the rotating unit to the fixing unit. Has been placed. The rotation-side optical element 3b is a light-emitting element that emits the image signal of the camera as light (optical signal), and the fixed-side optical element 3a emits light emitted from the rotation-side optical element 3b (core 2a, The light receiving element receives light (through the through holes 20a and 20b formed in 2b). Each optical element 3a, 3b is electrically connected to a fixed-side electronic substrate 9a and a rotating-side electronic substrate 9b fixed to the respective bases 1a, 1b by soldering or the like, and each electronic substrate 9a, 9b. Is fixed mechanically.

  A light-emitting element 4a for transmitting a control signal for controlling the camera (not shown) from the fixed side is electrically connected to the fixed-side electronic board 9a by solder connection or the like and mechanically fixed. Yes. The light emitting element 4a is composed of, for example, a near infrared light emitting diode. A light receiving element 4b that receives light emitted from the light emitting element 4a is electrically connected by soldering or the like and mechanically fixed to the electronic substrate 9b on the rotation side.

  In order to guide the light emitted from the light emitting element 4a to the light receiving element 4b, a light guide ring 6 that is an annular member that transmits light is disposed on the fixed base 1a along the outer periphery of the core 2a on the fixed side. Yes. The light emitted from the light emitting element 4a is guided to the light receiving element 4b through the light guide ring 6 and received by the light receiving element 4b. Thereby, a control signal for controlling a camera (not shown) is transmitted from the fixed unit to the rotating unit.

  An inner ring 5a of the bearing 5 is fixed to the outer periphery of the fixed base 1a. On the other hand, the outer ring 5b is fixed to the rotation base 1b so as to surround the inner ring 5a from the outside. A gear for rotating the outer ring 5 b is formed on the outer peripheral surface 54 b of the outer ring 5 b and is engaged with the motor gear 71 of the motor 7. When the motor 7 rotates, the rotation is transmitted to the outer ring 5b via the motor gear 71 and the outer peripheral gear, and the rotation base 1b (and the rotating part) to which the outer ring 5b is attached rotates about the rotation axis R.

  The inner ring 5a has a V-groove raceway surface on the outer periphery side, the outer ring 5b has a V-groove raceway surface on the inner periphery side, and a plurality of balls (rolling elements) 51 are arranged between both raceway surfaces. Has been. The outer ring 5 b has an inner peripheral side portion including the raceway surface divided into two in the axial direction, and one of them (the rotation base 1 b side) constitutes a pressure ring 52. The preload ring 52 is pressed against the ball 51 by the elastic force of the pressurizing spring 53a disposed between the pressurizing ring 52 and the rotation base 1b. In FIG. 2, for the sake of simplicity, the pressurizing spring 53 a is drawn in a tube shape, but in practice, a coil spring having a circumferential length substantially the same as that of the preload ring 52 is annularly arranged. is doing.

  Next, the configuration of the bearing 5 will be described in detail. In the bearing 5 shown in FIG. 1, the ball 51 and the inner ring 5a are in contact at two points, the ball 51 and the outer ring 5b are in contact at one point, and the ball 51 and the pressurizing ring 52 are in contact at one point. This is a four-point contact bearing. The four-point contact bearing supports loads in the radial direction and the thrust direction, and can support moment loads acting on the inner ring 5a and the outer ring 5b. In the case of a single-row deep groove bearing in which the balls are in contact at two points, two rows of bearings are required, which increases the axial dimension of the rotating device and complicates the device configuration. In the embodiment, by adopting a four-point contact bearing, the rotating device 100 is reduced in size and thickness (low profile).

  The balls 51 are usually made of stainless steel, but may be made of a resin material such as phenol resin, PPS (polyphenyl sulfide), PEEK (polyether ether ketone). The inner ring 5a, the outer ring 5b, and the pressurizing ring 52 may be made of a metal such as stainless steel, but are made of a resin material having self-lubricating properties such as POM (polyacetal) in consideration of weight reduction and workability. Is preferred. Further, the inner ring 5a, the outer ring 5b, and the pressurizing ring 52 may be made of metal, but by being made of resin, it is possible to take advantage of the advantage (no need for lubrication) compared to a metal bearing.

  As shown in FIG. 2, the pressurizing ring 52 presses the balls 51 in the direction of the rotation axis R (FIG. 1) by the elastic force of the pressurizing spring 53 a disposed between the pressurizing ring 52 and the pressurizing ring 53. Thereby, the pressurizing ring 52 can apply a uniform pressure to the ball 51 over the entire circumference.

  FIG. 3 is an enlarged view showing the structure of the pressurizing spring 53a, the pressurizing ring 52 that fixes the spring, and the rotation base 1b. The preload spring 53 a is a coil spring as described above, and the winding shaft X is arranged so as to make a round around the rotation axis R along the preload ring 52.

  The pressurizing spring 53a is held between the pressurizing ring 52 (first support member) and the rotation base 1b (second support member) while being sandwiched in the direction of the rotation axis R. The gap A between the pressurizing ring 52 and the rotary base 1b is set to a value smaller than the coil diameter of the pressurizing spring 53a (the dimension in the direction perpendicular to the winding axis X of the preload spring 53a). Therefore, when the cross-sectional shape of the pressurizing spring 53a (the cross-sectional shape orthogonal to the winding axis X) is circular, it is compressed between the pressurizing ring 52 and the rotary base 1b to become an elliptical shape. A pressurization is generated by elastic deformation of the pressurization spring 53 a, and a pressurization in the direction of the rotation axis R is applied to the pressurization ring 52.

  Here, when the pressurizing spring 53a is compressed in the coil radial direction as described above, it is conceivable that the coil wire is inclined (falls down) with respect to the coil radial direction. In such a case, if friction is generated at the contact surface between the coil wire of the preload spring 53a and the pressurizing ring 52 or the rotation base 1b, elements other than the elastic deformation of the coil wire are added to the preload generated by the preload spring 53a. Therefore, the applied pressure may fluctuate or may be affected by hysteresis. In order to generate the preload only by elastic deformation of the coil wire, it is necessary to prevent the coil wire from being inclined.

  Therefore, in the present embodiment, as shown in FIG. 3, the uneven portion 52a is formed in the portion where the preload spring 53a on the lower surface of the pressurizing ring 52 contacts, and the portion where the preload spring 53a on the upper surface of the rotating base 1b contacts. Also, the uneven portion 1c is formed. The concavo-convex portion 52a and the concavo-convex portion 1c may have any concavo-convex shape as long as they can prevent the coil wire of the pressurizing spring 53a from slipping. For example, as shown in FIG. 3, it is preferable that the V-shaped grooves are continuously formed at the same pitch as the coil pitch P of the pressurizing spring 53a. If comprised in this way, the coil wire material of the preload spring 53a will engage with each groove part of the uneven | corrugated | grooved part 52a and the uneven | corrugated | grooved part 1c, and it will regulate so that the coil wire which comprises the pressurization spring 53a may not tilt (do not fall down). Can do.

  As described above, according to the first embodiment, the preload spring 53a is elastically deformed in the coil radial direction (the direction orthogonal to the winding axis X) to generate the preload. The pressurization can be generated uniformly over the entire circumferential direction. Therefore, even if the pressurizing ring 52 is made thin, bending does not occur, and the apparatus can be reduced in size and thickness. Further, by suppressing the inclination of the coil wire rod of the preload spring 53a, the influence of the frictional force generated on the contact surface between the preload spring 53a and the pressurizing ring 52 or the rotation base 1b and the accompanying preload hysteresis is eliminated. be able to.

  Further, since a lubricant for suppressing friction at the contact surface between the preload spring 53a and the pressurizing ring 52 or the rotating base 1b is unnecessary, the advantage (no lubrication is required) when the bearing 5 is made of resin is utilized. be able to. Moreover, even if the bearing 5 is used for a long period of time, it is not necessary to replenish the lubricant, so that the life of the bearing 5 can be extended.

  Further, by forming the concave and convex portions 52a and the concave and convex portions 1c at the portions where the preload spring 53a of the pressurizing ring 52 and the rotary base 1b are in contact with each other, the inclination of the coil wire material of the preload spring 53a is surely suppressed, and the coil It can be elastically deformed in the radial direction. In addition, the uneven part may be formed only in any one of the pressurizing ring 52 and the rotation base 1b, and can exhibit a certain effect in suppressing the inclination of the coil wire rod.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described. In the first embodiment described above, the pressurizing spring 53a made of a coil wire is used, but in the second embodiment, a preload spring 53b made of a coiled strip-shaped plate material is used.

  FIG. 4 is an enlarged view showing the structure of the pressurizing spring 53b, the pressurizing ring 52 that fixes the spring, and the rotation base 1b in the present embodiment. In FIG. 4, the same components as those of the rotating device 100 described in the first embodiment are denoted by the same reference numerals.

  In the first embodiment, since the preload spring 53a is formed of a coil wire, the preload springs 52a and 1c (FIG. 3) are provided on the pressurization ring 52 and the rotary base 1b at portions that contact the pressurization spring 53a. It was necessary to suppress the inclination of the coil wire 53a. However, if the preload spring does not tilt, it is not necessary to provide the uneven portions 52a and 1c (FIG. 3).

  Therefore, in the present embodiment, as shown in FIG. 4, the preload spring 53b is constituted by a strip-shaped plate member wound in a coil shape. The gap A between the pressurizing ring 52 and the rotary base 1b is set to be narrower than the coil diameter of the pressurizing spring 53b. When the cross-sectional shape of the preload spring 53b (the cross-sectional shape orthogonal to the winding axis direction) is circular, the preload spring 53b is compressed by the pressurizing ring 52 and the rotary base 1b to become an elliptical shape. A pressurizing force is generated by the elastic deformation of the pressurizing spring 53a, and the pressurizing ring 52 is pressurized.

  In the case of the preload spring 53b formed of a strip-shaped plate material, even if it is compressed in the coil radial direction as described above, it does not tilt like the preload spring 53a of the first embodiment. This is considered to be because when the pressurizing spring 53b is formed of a strip-shaped plate material, a greater resistance against inclination is generated as compared with the preload spring 53a configured of the wire described in the first embodiment.

  As described above, in the second embodiment, as in the first embodiment, the pressurization ring 52 can be uniformly generated over the entire circumferential direction of the pressurization ring 52. Even if it is made thin, no bending occurs, which can contribute to the downsizing and thinning of the apparatus. Further, since the pressurizing spring 53b is not tilted even if it is compressed between the pressurizing ring 52 and the rotating base 1b, the frictional force generated on the contact surface with the pressurizing ring 52 and the rotating base 1b, and the accompanying force The influence of the preload hysteresis can be eliminated, and the pressurization generated only by the elastic deformation of the preload spring 53 b can be applied to the pressurization ring 52.

  Further, as compared with the first embodiment described above, it is not necessary to provide an uneven portion on the preload ring 52 or the rotation base 1b, and the surfaces that contact the preload ring 53 and the preload spring 53b of the rotation base 1b are, for example, smooth surfaces. Therefore, the apparatus configuration and the manufacturing process can be simplified. Further, as described in the first embodiment, the life of the bearing 5 can be extended.

  In each of the embodiments described above, the pressurizing spring 53a (53b) is arranged in a ring shape. However, the pressurizing spring 53a (53b) is not particularly limited to the ring shape, and is arranged in a form as required, such as a square or a hexagon. Can be set.

  Further, both ends of the pressurizing spring 53a (53b) may be connected by welding or the like. Further, the preload spring 53a (53b) may be disposed, for example, in a circumferential groove provided on the rotary base 1b. In this case, it is necessary to connect both ends of the preload spring 53a (53b). Absent. If comprised in this way, it will become possible to manufacture at a low price, and handling, such as transportation and storage, will also become easy.

  Further, in each of the above-described embodiments, the preload ring 52 is provided with the outer ring 5b of the bearing 5 as a divided structure, but the inner ring 5a may have a divided structure.

It is sectional drawing which shows the structure of the rotating apparatus in Embodiment 1 of this invention. It is a disassembled perspective view which shows the structure of the rotating apparatus in Embodiment 1 of this invention. It is a figure which expands and shows the structure of the pressurization spring in Embodiment 1 of this invention, and its supporting member. It is a figure which expands and shows the structure of the pressurization spring in Embodiment 2 of this invention, and its supporting member.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1a Fixed base, 1b Rotating base, 1c Uneven part, 2a, 2b Core, 3a, 3b Optical element, 4a Light emitting element, 4b Light receiving element, 5a Inner ring, 5b Outer ring, 51 balls, 52 Pressurizing ring, 52a Uneven part, 53a 53b Pressure spring, 6 Light guide ring, 7 Motor, 100 Rotating device.

Claims (8)

A coil spring;
A first support member and a second support member sandwiching the coil spring in the coil radial direction;
The gap between the first support member and the second support member is smaller than the coil diameter of the coil spring, and the first and second support members compress the coil spring in the direction of the coil diameter. A pressurizing mechanism characterized by generating preload by means of The coil spring is formed of a wire material,
2. The preload mechanism according to claim 1, wherein portions of the first and second support members that come into contact with the coil spring have an uneven shape corresponding to a wire material of the coil spring.   The pressurizing mechanism according to claim 1, wherein the coil spring is formed of a strip-shaped plate material. A four-point contact bearing comprising an outer ring, an inner ring, and a rolling element arranged to contact the outer ring and the inner ring at two locations, wherein the outer ring or the inner ring is divided in the axial direction;
4. The four-point contact bearing comprising the pressurizing mechanism according to claim 1, wherein a preload is applied to the outer ring or the inner ring divided in the axial direction.   The four-point contact bearing according to claim 4, wherein the coil spring is disposed around a rotating shaft defined as a central axis of the outer ring and the inner ring.   The four-point contact bearing according to claim 5, wherein the coil spring is annularly disposed so as to surround the rotating shaft. A fixed part;
A rotating part;
A rotating device comprising: the four-point contact bearing according to any one of claims 4 to 6, wherein the rotating portion is rotatably supported with respect to the fixed portion. An optical signal transmission device that is provided in the rotation device according to claim 7 and transmits an optical signal between the rotation unit and the fixed unit,
A light emitting element that emits light as an optical signal;
An annular light guide ring that propagates light emitted from the light emitting element;
An optical signal transmission device comprising: a light receiving element that receives light propagating through the light guide ring.

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