JP2008193951A - Unit for supporting rotary member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a unit for supporting rotary member that prevents grease from leaking outside and enabling a rotary member to be stably and continuously rotated over a long period of time, at a fixed rotation precision. <P>SOLUTION: The unit for supporting rotary member comprises a main shaft 8 set upright, bearings 2 and 4 equipped with a stationary ring and a rotating ring respectively, gears G1 and G2 set on each end side of a drive shaft and the main shaft, respectively, a rotary member 32 attached to the other side of the main shaft, and a case 40 housing the bearings and the gears. In this unit for supporting rotary member, relative to the gear disposed in the closest proximity to the rotary member, for preventing foreign matters from infiltrating the inside, an annular slinger 25 is set firmly on the flank 12c, on the gear side of the stationary ring 12 and maintained in stationary condition; the inner circumferential surface 25a of the slinger 25 is positioned a predetermined space L1, separated from the main shaft and is also positioned in a noncontact fashion with the rotating ring 10 and the gears; the portion 8d of the main shaft, which faces the inner circumferential surface of the slinger, is constituted with the diameter widened more from the outer circumference of the main shaft toward the inner circumferential surface of the slinger 25; and the portion of the main shaft is provided with a recessed continuous air groove 8m, extending over the whole circumference. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to, for example, a grass cutter, a brush cutter and a lawn mower used for cutting off grass (e.g., lawn and weed) growing on the ground surface from near the root, or an electric tool, a concrete drill, etc. The present invention relates to an improvement of a rotating member support unit that pivotally supports a rotating member such as a cutting blade (rotating blade) attached thereto.

FIG. 4 shows an example of a configuration of a mower provided with such a rotating member support unit. In the configuration shown in the figure, the mower A includes an operation tube 30 that extends linearly, and a rotary member support unit (hereinafter referred to as a rotary blade unit) U2 provided on one end side of the operation tube 30. A driving device (engine) 34 provided on the other end side of the operation tube 30 is provided.
In this case, the operation tube 30 is provided with a drive shaft 38 that is rotated by a drive force (rotational output) generated by the engine 34, and the drive shaft 38 is a rolling bearing (hereinafter referred to as drive shaft). (Referred to as a bearing) 6 is rotatably supported. A gear (hereinafter referred to as a drive shaft gear) G1 is provided at the end of the drive shaft 38 opposite to the engine 34, and the drive shaft bearing 6 is externally fitted to the drive shaft gear G1. The drive shaft 38 is rotatably supported.

  3 (a) and 3 (b), the rotary blade unit U2 includes a main shaft 8 extending in a predetermined direction and two rolling bearings that rotatably support the main shaft 8. (Hereinafter referred to as the rotary blade side bearing 2 (lower bearing in FIG. 3A) and the gear side bearing 4 (upper bearing in FIG. 3)) and the rotational force of the drive shaft 38 to transmit to the main shaft 8. And a pair of gears (the drive shaft gear G1 (the right gear in the figure)) provided on one end side (the left end side and the upper end side in the figure) of the drive shaft 38 and the main shaft 8, respectively. And a main shaft gear G2 (referred to as the left side gear in the figure) and a rotatable rotating member (cutting blade) 32 attached to the other end side (the lower end side in the figure) of the main shaft 8.

In this case, the main shaft 8 is erected so as to extend in a substantially vertical direction when the mower A is in use, and the drive shaft 38 has a predetermined inclination angle (drive shaft 38 with respect to the main shaft 8). And an angle formed between the main shaft 8 and the main shaft 8 and is connected to the main shaft 8 via the drive shaft gear G1 and the main shaft gear G2.
Further, the rotary blade side bearing 2 is positioned between the cutting blade 32 and the main shaft gear G2 in the middle of the extending direction of the main shaft 8, or in another way, while the gear side bearing 4 is It is positioned at the end of the main shaft 8 opposite to the cutting blade 32 (upper end in FIG. 3A). Further, the operation tube 30 is provided with a protective cover 42 (FIG. 4) for protecting the operator from the cutting blade 32 at a predetermined position near the cutting blade 32.

  According to such a configuration, when the engine 34 rotates the drive shaft 38, the rotational force is transmitted to the main shaft gear G2 via the drive shaft gear G1, and the main shaft 8 can be rotated by the rotational force. Thereby, while changing the direction of the rotational force generated from the engine 34, the cutting blade 32 attached to the main shaft 8 can be rotated while the speed is reduced. The operator can cut the vegetation by moving the cutting blade 32 while supporting the whole of the mower A by the operation handle 36 attached to a predetermined position of the operation tube 30 near the engine 34.

  By the way, regarding such a mower, various measures for improving convenience and safety have been conventionally known. For example, Patent Document 1 discloses a configuration of a mower capable of arbitrarily changing the angle of a connection pipe (operation pipe), thereby facilitating the mowing of vegetation even on sloping ground. And the convenience of the mower is improved. On the other hand, for example, Patent Document 2 discloses a configuration of a mower capable of easily and reliably attaching a cutting blade (rotating blade) to a main shaft, whereby the cutting blade (rotating blade) can be removed from the main shaft. It is possible to effectively prevent the detachment and improve the safety of the mower.

  Further, in this mower A, the friction and wear of the portions where the teeth of the drive shaft gear G1 and the main shaft gear G2 contact each other are reduced, and the rotary blade side bearing 2, the gear side bearing 4 and the drive shaft bearing 6 are prevented from seizing. For the purpose of extending the fatigue life, etc., the gears G1, G2 and the bearings 2, 4, 6 can be lubricated. As a result, the cutting blade 32 can be stably and smoothly over a long period of time. It can be rotated, and the convenience and safety of the mower A can be improved.

  Therefore, for example, in order to lubricate the drive shaft gear G1 and the main shaft gear G2, grease containing extreme pressure agent (hereinafter referred to as gear lubrication grease) is contained in the predetermined space S surrounding the gears G1 and G2. It is filled (enclosed) so as to have a volume ratio of approximately 70% to 100% with respect to the space volume of the part S. In this case, the gear lubrication grease is a consistency No. specified by the National Lubricating Grease Institute (NLGI). As an example, the grease is composed of lithium soap as a thickener and mineral oil as a base oil.

  At that time, as an example, the gear side bearing 4 is a so-called open type (open type) bearing in which a sealing member (contact type seal, non-contact type seal or shield, etc.) is not provided. In contrast to the structure, the rotary blade side bearing 2 has a sealed type bearing structure in which contact type rubber seals 20 and 22 are interposed between the inner and outer rings 10 and 12. Is a sealed ball bearing incorporated between the inner and outer rings 10,12. In order to lubricate the rotary blade side bearing 2, the rotary blade side bearing 2 has, as an example, a grease in which the thickener is lithium soap and the base oil is a mineral oil (hereinafter referred to as bearing lubrication grease). ) Is enclosed inside the bearing. In this case, as an example, the rubber seals 20 and 22 have their outer diameter portions fixed to the outer ring 12 of the rotary blade side bearing 2, and their inner diameter portions (lip portions) 20 l and 22 l of the rotary blade side bearing 2. It is positioned so as to be in sliding contact with the seal groove formed in the inner ring 10.

In the rotary blade unit U2 in which the gears G1 and G2 and the bearings 2 and 4 are lubricated in this way, the rotary blade side bearing 2 is always provided only via the rubber seal (seal located on the gears G1 and G2 side) 20. In contact with gear lubrication grease.
Further, when the mower A is in use, the drive shaft gear G1 and the rotary blade side bearing 2 and the main shaft gear G2 and the rotary blade side bearing 2 are arranged vertically with the gears G1 and G2 facing upward. A large amount of grease is deposited on the outer surface of the rubber seal 20 located on the gears G1, G2 side (surface on the gears G1, G2 side) by its own weight, and presses the rubber seal 20. In addition, the outer surface of the rubber seal 20 (gear G1) where the gear lubrication grease is located on the gears G1 and G2 side is also caused by the pressure change in the space S due to the rotation of the main shaft 8 and the vibration due to the rotation of the rotary blade side bearing 2. , G2 side surface) and the seal 20 is pressed.

When the rubber seal 20 continues to be pressed by the gear lubrication grease, as a result, the gear lubrication grease is transferred from the sliding contact portion between the lip portion 201 of the seal 20 and the seal groove of the rotary blade side bearing 2 to the rotary blade side bearing. 2 may leak into (intrude).
In this case, for example, grease having a configuration similar to gear lubrication grease is applied as grease (bearing lubrication grease) sealed in the rotary blade side bearing 2, so that the bearing lubrication grease is mixed with the gear lubrication grease. As a result, it is possible to minimize the quality change or malfunction of the grease.
JP 2004-194521 A JP-A-8-130959

  However, when leakage (penetration) of the gear lubrication grease as described above proceeds into the bearing, the amount of grease in the rotary blade side bearing 2 increases from the set value, and stirring and shearing are activated, and the grease is It may soften. When such softening of the grease occurs, the sliding contact portion between the lip portion 22l of the rubber seal 22 of the rotary blade side bearing 2 (the seal located on the cutting blade 32 side) and the seal groove of the rotary blade side bearing 2, The grease may leak out of the rotary blade side bearing 2 from the air holes 22h provided in the seal 22 or the like. In this case, for example, the leaked grease adheres to the cutting blade 32 (the state of the grease Gb in FIG. 3A), which may deteriorate the rotational accuracy of the cutting blade 32, and also against vegetation and soil. There is also a risk of adverse effects.

  Further, when the gear lubrication grease continuously leaks (enters) into the rotary blade side bearing 2 and further to the outside of the rotary blade side bearing 2, the drive shaft gear G1 and the main shaft gear G2 become insufficiently lubricated. Since the teeth of the gears G1 and G2 are rubbed against each other and worn, the gears G1 and G2 may not rotate smoothly, and their rotational accuracy may deteriorate.

  As a measure for avoiding such inconvenience, for example, as a gear lubrication grease, the NLGI consistency is No. 3 or No. No. 4 grease, that is, NLGI consistency No. Grease harder than grease No. 2 is applied to suppress softening due to stirring or shearing of the grease, and the grease is adhered to the inner wall of the predetermined space S surrounding the drive shaft gear G1 and the main shaft gear G2. There are measures and measures to reduce the filling amount (filling amount) of the grease.

  However, when the hardness of the gear lubrication grease is increased, the fluidity of the grease decreases and the amount of grease that contributes to the lubrication of the drive shaft gear G1 and the main shaft gear G2 decreases. As a result, the gears G1 and G2 are lubricated. For example, as in the case described above, the teeth of the gears G1 and G2 may be rubbed against each other and worn. On the other hand, when the filling amount (encapsulation amount) of the gear lubrication grease is decreased, the grease does not sufficiently spread into the space S, and as a result, the drive shaft gear G1 and the main shaft gear G2 become insufficiently lubricated, and the same situation occurs. It may become.

  The present invention has been made to solve such a problem, and the object thereof is to provide a slinger that is always kept stationary with respect to a rolling bearing that pivotally supports a rotating member (for example, a cutting blade), In addition to expanding the diameter and width of the portion facing the slinger, and providing a spiral air groove in the facing portion, the grease sealed inside is prevented from leaking to the outside, and the rotating member is extended over a long period of time. An object of the present invention is to provide a rotating member support unit that can be stably rotated with a constant rotational accuracy.

In order to achieve such an object, a rotating member support unit according to the present invention includes a main shaft extending in a predetermined direction, and a stationary wheel and a rotating wheel arranged to face each other so as to be relatively rotatable. A plurality of rolling bearings that rotatably support the main shaft and the drive shaft and one end side of the main shaft that are provided on one end side of the main shaft so as to transmit the rotational force of the drive shaft rotated by the driving device to mesh with each other. At least one set of gears, a rotating member attached to the other end of the main shaft, and a case for housing the main shaft, a rolling bearing, and the gears are provided.
In such a rotating member support unit, at least the rolling bearing disposed closest to the rotating member has an annular slinger closely attached to the side surface of the stationary ring on the gear side in order to prevent foreign matter from entering the rolling bearing. The slinger is provided in close proximity, and is positioned so that the inner peripheral surface thereof is opposed to the main shaft at a predetermined interval, and the rotating ring and the gear of the rolling bearing are not in contact with each other. So that it is always kept stationary. Further, the main shaft is configured such that at least a portion facing the inner peripheral surface of the slinger is expanded in diameter toward the inner peripheral surface of the slinger rather than the outer periphery of the main shaft. An air groove which is continuous in a concave shape is provided.

In this case, the air groove is formed in a spiral shape that is continuous from the rolling bearing side disposed closest to the rotating member toward the gear side, and the spiral direction is the same as the rotation direction of the main shaft. It is configured to be wound around.
Further, as an example, a rolling bearing disposed closest to the rotating member includes at least a pair of sealing members forming an annular shape for sealing the inside of the rolling bearing between the stationary wheel and the rotating wheel with the rolling element interposed therebetween. With the slinger fixed to the inner wall of the case, the end surface on the rolling bearing side is brought into close contact with the side surface on the gear side of the stationary ring and is opposed to the sealing member with a predetermined interval. On the other hand, the end face on the gear side may be positioned by being recessed in the axial direction by a predetermined amount from the end face on the gear side opposite to the main shaft.
Note that a cutting blade for cutting off the vegetation growing on the ground surface from the vicinity of the root can be attached to the main shaft as a rotating member.

  According to the rotating member support unit of the present invention, the rolling bearing that pivotally supports the rotating member (for example, the cutting blade) is provided with the slinger configured to be stationary at all times, and the opposing portion of the main shaft to the slinger is expanded and widened. By providing a spiral air groove in the facing portion, it is possible to prevent leakage of the grease enclosed inside to the outside and to rotate the rotating member stably with a constant rotational accuracy over a long period of time. Can continue to.

  Hereinafter, a rotating member support unit according to an embodiment of the present invention will be described with reference to the accompanying drawings. In the present invention, for example, a mower, a brush cutter, a lawn mower, a power tool, a concrete drill, or the like, the main shaft extends in a predetermined direction, and supports various rotating members that rotate together with the main shaft. Although it can be applied to a rotating member support unit, in the following, a rotating blade (rotating blade) for cutting away vegetation growing on the ground surface from near the root is used for a mower attached to the main shaft as a rotating member. A configuration of the rotary blade unit will be described assuming a blade unit as an example. In this case, as an overall configuration of the mower according to the present embodiment, the same configuration as that of the conventional mower A (FIG. 4) described above is assumed as an example. Further, since the basic configuration of the rotary blade unit according to the present embodiment is the same as the conventional rotary blade unit U2 (FIG. 3A) described above, the configuration is the same as or similar to the rotary blade unit U2. Are denoted by the same reference numerals in the drawings, and the description thereof is omitted.

  FIGS. 1A to 1C show a rotary blade unit U1 (rotary member support unit) of a mower according to an embodiment of the present invention. The rotary blade unit U1 has a predetermined direction. The main shaft 8 receives the rotational force of the extended main shaft 8, the plurality of rolling bearings 2 and 4 that rotatably support the main shaft 8, and the drive shaft 38 rotated by the drive device (engine 34 (see FIG. 4)). For transmission, at least one set of gears G1, G2 provided on one end side (left end side and upper end side in FIG. 1A) of the drive shaft 38 and the main shaft 8 and meshing with each other, A rotating member (cutting blade 32) attached to the other end side (the lower end side of FIG. 1A) is provided.

  The main shaft 8, the rolling bearings 2, 4 and the gears G1, G2 are respectively housed in a cylindrical case 40, and the cutting blade 32 is fastened and fixed to the main shaft 8 by a fastening member (screw). It is attached to the outside of the case 40 (the lower side of FIG. 1A).

The main shaft 8 is erected so as to extend in a substantially vertical direction when the mower is in use, whereas the drive shaft 38 has a predetermined inclination angle (with respect to the drive shaft 38). And an angle formed between the main shaft 8 and the main shaft 8 via the drive shaft gear G1 and the main shaft gear G2. The inclination angle is arbitrarily set according to, for example, the usage environment or purpose of use of the mower, and is not particularly limited here. As an example, in the present embodiment, the drive shaft 38 is the main shaft 8. Is inclined at an inclination angle of about 120 ° (about 30 ° with respect to the cutting blade 32 in another way) (FIG. 1A).
Further, in the configuration shown in FIGS. 1A and 1B, the main shaft 8 has a relatively large diameter portion on the gears G1, G2 side (upper side in the figure) with a predetermined stepped portion 8g as a boundary. 8a is provided, and a small diameter portion 8b having a relatively small diameter is provided on the cutting blade 32 side (lower side in the figure).

  In the configuration shown in FIG. 1A, the rotary blade unit U1 includes, as an example, two rolling bearings (the rotary blade side bearing 2 (the lower bearing in FIG. 1A)) and the gear side bearing 4 (the same figure). The rotary blade side bearing 2 and the gear side bearing 4 are externally fitted to the main shaft 8 and are internally fitted to the case 40 so that the main shaft 8 can be rotated freely. I support it. In this case, as an example, the rotary blade side bearing 2 is positioned between the cutting blade 32 and the gear G2 (main shaft gear to be described later) approximately in the middle of the extending direction of the main shaft 8, in another way. The gear-side bearing 4 is positioned at the end of the main shaft 8 opposite to the cutting blade 32 (the upper end in FIG. 1A).

  In the configuration shown in FIG. 1A, the rotary blade unit U1 includes, as an example, a set of gears (drive shaft gear G1 (the gear on the right side in FIG. 1A)) and main shaft gear G2 (shown in FIG. 1A). The left side gear)) is provided, the drive shaft gear G1 is externally fitted to the drive shaft 38, and the main shaft gear G2 is externally fitted to the main shaft 8 to mesh with each other. As a result, the drive shaft gear G1 and the main shaft gear G2 rotate the cutting blade 32 attached to the main shaft 8 while changing the direction of the rotational force generated by the engine 34 (FIG. 4) and reducing the speed thereof. It fulfills the function of a so-called transmission.

  The type, size, shape, number of teeth, pitch, and the like of the drive shaft gear G1 and the main shaft gear G2 are arbitrarily set according to the size of the drive shaft 38 and the main shaft 8, the positional relationship between the two shafts, and the like. Therefore, there is no particular limitation here. For example, as in the case of the mower according to the present embodiment, the drive shaft 38 and the main shaft 8 are connected at a predetermined inclination angle (for example, about 120 °) (see FIG. 1A). As the drive shaft gear G1 and the main shaft gear G2, bevel gears such as a bevel gear, a helical bevel gear, and a spiral bevel gear may be applied.

  In the present embodiment, as shown in FIG. 1B, the rotary blade side bearing 2 is arranged so that a rotating wheel (hereinafter referred to as an inner ring) 10 and a stationary wheel (hereinafter referred to as an outer ring) 12 face each other so as to be relatively rotatable. A plurality of rolling elements (balls) 14 are incorporated between the inner ring 10 and the outer ring 12 so as to be able to roll. In this case, the rolling elements (balls) 14 are rotatably held one by one in a pocket formed in a ring-shaped cage (for example, a corrugated mating cage) 16 and the inner ring 10 and It is incorporated between the raceway surfaces of the outer ring 12. Thereby, each rolling element (ball) 14 can roll between the inner and outer rings 10 and 12 (between the raceway surfaces) without the rolling surfaces being in contact with each other, and as a result, the respective rolling elements. It is possible to prevent an increase in rotational resistance or seizure caused by friction between the (balls) 14 coming into contact with each other.

  Note that the types and sizes of the rotary blade side bearing 2, the rolling elements (balls) 14, and the cage 16 are arbitrarily set according to the size of the mower, the rotational output of the driving device (engine), and the like. Therefore, there is no particular limitation here. For example, as the rotary blade side bearing 2, in addition to the single row deep groove ball bearing shown in FIGS. 1A and 1B, a double row deep groove ball bearing, various roller bearings, and the like can be applied. In addition to the balls shown in FIGS. 1A and 1B, rollers such as cylindrical rollers, tapered rollers, and spherical rollers (rubber rollers) may be applied as the rolling element 14. Further, as the retainer 2c, a so-called corrugated retainer as shown in FIGS. 1A and 1B, a crown retainer, a cage retainer, or the like may be applied.

  Further, in the rotary blade side bearing 2, a rolling element (ball) 14 is sandwiched between the inner ring 10 and the outer ring 12, and the rotary blade side bearing is placed on both sides (the upper side and the lower side in FIG. 1B). Sealing members (contact type rubber seals (hereinafter simply referred to as “seal”)) 20 and 22 for sealing 2 are provided. By providing the seals 20 and 22 in this way, foreign matters (for example, shaved wood scraps, muddy water, and dust) enter the inside from the outside of the rotary blade side bearing 2 (that is, the outside of the rotary blade unit U1). In addition, the lubricant (for example, bearing lubrication grease described later) is prevented from leaking to the outside. Further, gear lubrication grease, which will be described later, is prevented from leaking (penetrating) into the rotary blade side bearing 2 and mixed with the bearing lubrication grease.

  In the configuration shown in FIG. 1B, as an example, the seals 20 and 22 are made of various types of annular core bars 20c and 22c formed by press working or the like so that the cross section is L-shaped. Are connected by an elastic material (for example, a resin material such as rubber or plastic). Seal lips 20l and 22l made of such an elastic material are formed on the inner diameter portions of the seals 20 and 22. The seals 20 and 22 have outer diameter portions fixed to mounting grooves formed on the outer ring 12 of the rotary blade side bearing 2, and inner diameter portions formed on the inner ring 10 of the rotary blade side bearing 2. It is positioned so that it slides on.

  However, the shape of the seals 20 and 22 is not particularly limited to the shape described above. For example, the core metal may be configured as a flat annular flat plate, or the entire core metal may be connected to the elastic material. Good. Further, a plurality of (for example, three) seal lips may be formed. When the core bars 20c and 22 are connected to various elastic materials, various methods such as adhesion, caulking, coating, and injection molding can be arbitrarily selected and used as the connection method.

The size of the seals 20 and 22 (for example, the width (the distance in the horizontal direction in FIG. 1B) and the thickness (the distance in the vertical direction in FIG. 1)) is, for example, the size of the rotary blade side bearing 2. Since it is arbitrarily set according to the above, it is not particularly limited here. However, the thickness of the seals 20 and 22 (the distance in the vertical direction in FIG. 1B) is such that the seals 20 and 22 are the side surfaces of the inner ring 10 of the rotary blade side bearing 2 and the gears G1 and G2 side of the outer ring 12 (see FIG. It is preferable that the thickness is such that the inner surface of the bearing 2 is recessed more than the upper surface).
As an example, in the present embodiment, the thickness of the seals 20 and 22 is set so that the depth of the recesses from the side surfaces of the inner and outer rings 10 and 12 is about 0.25 mm, and the seals 20 and 22 The case where it positions between the inner and outer rings 10 and 12 is assumed.

  Here, in this embodiment, as an example, the contact-type seals 20 and 22 as shown in FIG. 1B are applied to the sealing member. For example, the outer diameter portion of the sealing member is an outer ring. 12 is a non-contact type seal that is fixed to the mounting groove 12 and has an inner diameter portion that does not contact the seal groove of the inner ring 10 (for example, a whole or a part of a steel plate core is made of various elastic materials (for example, rubber, plastic, etc. Or a non-contact type shield (for example, a shield formed by press molding from a thin metal plate such as a stainless steel plate or an iron plate) may be applied.

  Further, of the two seals 20 and 22, the seal 22 positioned on the cutting blade 32 side (the lower side in FIG. 1B) which is a rotating member has a through hole 22h for suppressing a pressure change inside the bearing. Is provided. In this case, the through hole 22h penetrates at least the outer diameter portion of the seal 22 from the inner side to the outer side of the seal 22 (from the upper side to the lower side in FIG. 1B). Is formed.

  In the configuration shown in FIG. 1B, the through-hole 22h is, for example, a portion consisting only of a connection of an outer diameter portion of the seal 22 by an elastic material (for example, a resin material such as rubber or plastic), that is, a cored bar 22c. It is formed in the site | part only of the elastic material which does not contain. In this way, by forming the through hole 22h only in the elastic material, the through hole 22h is not normally open, and the inside of the rotary blade side bearing 2 is pressurized or depressurized. Only when the seal 22 is elastically deformed, it can be configured as a so-called air valve that is in an open state and discharges the inside air of the bearing 2 or allows the outside air of the bearing 2 to flow in.

  Note that the shape, size, position, number, and the like of the through holes 22h are not particularly limited here because they are arbitrarily set according to the shape, size, and the like of the seal 22, for example. For example, the through hole 22h is not formed on the outer diameter portion of the seal 22, or may be formed on the inner diameter portion (specifically, the seal lip 22l that is in sliding contact with the wall portion of the seal groove) in addition to the outer diameter portion. Good. Further, for example, only one through hole 22h may be formed in the outer diameter portion of the seal 22, or a plurality of through holes 22h may be formed at predetermined intervals along the circumferential direction.

  On the other hand, of the two seals 20 and 22, the seal 20 positioned on the drive shaft gear G1 and main shaft gear G2 side (the upper side in FIG. 1B) has both an outer diameter portion and an inner diameter portion. A through hole for suppressing a pressure change inside the bearing, that is, a through hole corresponding to the through hole 22h formed in the above-described seal 22 is not provided.

  As described above, in the rotary blade side bearing 2, the drive shaft gear G1 and the main shaft gear G2 side (the upper side in FIG. 1B) are completely sealed by the seal 20 while the cutting blade 32 is inside. The side (the lower side in FIG. 1B) is not completely sealed because the seal 22 has a through hole 22h. That is, the inside of the rotary blade side bearing 2 is openable to the outside of the bearing through the through hole 22h of the seal 22 on the cutting blade 32 side (lower side in FIG. 1B). Inside air can be discharged from the through hole 22h to the outside of the bearing, and outside air can be allowed to flow into the bearing.

Thereby, for example, when the inside of the bearing is pressurized by the rotation of the rotary blade side bearing 2, the seal 22 (connection portion by the elastic material) is elastically deformed to open the through hole 22h, and the through hole 22h is opened. By discharging the inside air, it is possible to suppress an increase in the pressure inside the bearing and to keep the internal pressure of the bearing constant. As a result, for example, the seal lips 20l and 22l of the seals 20 and 22 are not separated from the wall portion of the seal groove due to an increase in bearing internal pressure.
On the other hand, for example, when the inside of the bearing is depressurized by stopping the rotary blade side bearing 2, the through hole 22h is similarly opened, and the pressure inside the bearing is reduced by flowing in the outside air from the through hole 22h. This can be suppressed and the internal pressure of the bearing can always be kept constant. As a result, for example, the seal lips 20l and 22l of the seals 20 and 22 are not attracted to the wall portion of the seal groove due to a decrease in the bearing internal pressure, and the rotational torque of the rotary blade side bearing 2 does not increase.

Note that, as in this embodiment, a mower equipped with the engine 34 (FIG. 4) as a driving device has a large driving force (rotational output), and therefore, for example, the rotational torque of the rotary blade side bearing 2 is high. Even if it increases, the rotational accuracy of the cutting blade 32 is hardly affected, and the deterioration of the rotational accuracy of the cutting blade 32 due to the increase in the rotational torque can be minimized. For this reason, for example, grease (such as bearing lubrication grease to be described later) leaks from the through hole 22h of the seal 22 on the cutting blade 32 side (lower side in FIG. 1B) to the outside of the rotary blade side bearing 2, and the leakage occurs. In consideration of inconvenience caused when grease adheres to the cutting blade 32, the seal 22 is not formed with the through hole 22h, and the seal 22 is connected to the drive shaft gear G1 and the main shaft gear G2 (upper side of FIG. 1 (b)). A configuration similar to that of the seal 20 of FIG.
Thus, the rotary blade side bearing 2 has a configuration in which the inside is completely sealed, and the grease (such as the bearing lubricating grease) sealed in the bearing can be reliably prevented from leaking to the outside of the bearing.

  In addition to the seals 20 and 22, the rotary blade side bearing 2, which is a rolling bearing disposed closest to the rotary member (cutting blade 32), has foreign matter (for example, gear lubrication grease, dust, etc.) inside the bearing. ) Is provided in close contact with the side surface 12c of the outer ring 12 on the drive shaft gear G1 and main shaft gear G2 side (upper side in FIG. 1B). The slinger 25 is positioned with its inner peripheral surface 25a facing the main shaft 8 with a predetermined distance (distance L1 shown in FIGS. 1B and 1C) and facing the inner ring of the rotary blade side bearing 2. 10 and the gears G1 and G2 are positioned so as to be in non-contact with each other, so that the stationary state is always maintained.

  As an example, in the configuration shown in FIG. 1B, the outer diameter is approximately the same as the diameter of the inner wall of the case 40 (wall portion forming a predetermined space S surrounding the drive shaft gear G1 and the main shaft gear G2) 40s. The slinger 25 is configured to have a cylindrical shape whose inner diameter is set to be slightly larger than the diameter of the large diameter portion 8a of the main shaft 8. In this case, since the outer diameter and the inner diameter of the slinger 25 are set to the same diameter over the entire length (distance from the upper end to the lower end of FIG. 1B), the extending direction of the main shaft 8 (vertical direction) The shape of the cross section (vertical cross section) with respect to (in the vertical direction in the figure) forms a rectangle (for example, a rectangle in the figure).

  The slinger 25 is fixed (for example, an interference fit) to the inner wall 40s of the case 40. In this state, the end surface on the rotary blade side bearing 2 side (the lower surface in FIG. 1B (hereinafter referred to as the slinger lower surface)) 25b. Is in close contact with the side surface (upper surface in the figure) 12c of the outer ring 12 on the side of the gears G1, G2. Similarly, in this state, the slinger 25 has the slinger lower surface 25b opposed to the seal 20 with a predetermined interval.

Further, in the present embodiment, as shown in FIG. 1B, at least a portion (hereinafter referred to as a facing portion) 8 d where the main shaft 8 is opposed to the inner peripheral surface 25 a of the slinger 25 is more than the outer periphery of the main shaft 8. The diameter is increased by a predetermined size (distance S2 (radius value) shown in the figure) toward the inner peripheral surface 25a.
As an example, in the configuration shown in FIG. 1B, the upper side in the axial direction (extending direction of the main shaft 8, that is, the vertical direction (the vertical direction in the figure)) of the facing portion 8d with the facing portion 8d as a boundary. By reducing the diameter by a predetermined size (distance S2 (radius value) shown in the figure) (so-called meat stealing), the facing portion 8d of the main shaft 8 is directed toward the inner peripheral surface 25a of the slinger 25, The structure protrudes by a predetermined size (distance S2 (radius value) shown in the figure). In this case, since the facing portion 8d is provided on the large diameter side, that is, the large diameter portion 8a of the main shaft 8 with the stepped portion 8g as a boundary, the main shaft 8 is disposed below the facing portion 8d in the axial direction. The small diameter portion 8b is provided.

  Further, as shown in FIGS. 1B and 1C, the facing portion 8d of the main shaft 8 (specifically, the facing surface with the inner peripheral surface 25a of the slinger 25 (hereinafter referred to as the facing portion peripheral surface) 8s) Is provided with a groove (hereinafter referred to as an air groove) 8m that is continuously concaved over the entire circumference. In this case, the air groove 8m is formed on the drive shaft gear G1 and the main shaft gear G2 side from the rotary blade side bearing 2 side which is a rolling bearing disposed closest to the rotary member (cutting blade 32) (FIG. 1 (b), ( c) It is formed in a continuous spiral shape from the lower side to the upper side), and the spiral is wound in the same direction as the rotation direction of the main shaft 8.

  As an example, in the present embodiment, the rotary blade unit U1 is assumed to be operated with the main shaft 8 (that is, the cutting blade 32) rotating counterclockwise (counterclockwise), and FIG. ) Shows a configuration in which the air groove 8m is formed in a spiral shape in which the air groove 8m is wound counterclockwise (counterclockwise) like the main shaft 8 and is continued from the lower side to the upper side. That is, in the configuration shown in FIG. 1C, the air groove 8m has a female screw structure that proceeds from the lower side to the upper side. When the rotary blade unit U1 is operated by rotating the spindle 8 (that is, the cutting blade 32) clockwise (clockwise), the air groove 8m is clockwise (clockwise) in the same manner as the spindle 8. ) To form a spiral wound around the lower side to the upper side.

  In this way, the main shaft 8 is rotated by forming a spiral shape in which the air groove 8m is wound in the same direction as the rotation direction of the main shaft 8 (for example, counterclockwise as an example) and continuing from the lower side to the upper side. Then, an air flow from the lower side to the upper side (upward in the vertical direction) is generated in the air groove 8m. The air flow is pressurized between the air groove 8m and the inner peripheral surface 25a of the slinger 25 when flowing through the air groove 8m from the lower side to the upper side, and the upward air flow is directed upward by the pressurized air flow. Pressure (resistance against vertical downward force) can be generated (so-called Archimedes screw pump action).

The size (width (distance in the vertical direction in FIG. 2) and depth (distance in the horizontal direction in FIG. 2)), shape, pitch, formation position, and the like of the air groove 8m are the size of the facing portion 8d of the main shaft 8. What is necessary is just to set arbitrarily according to thickness (diameter dimension, thickness, etc.), a shape, etc., and it does not specifically limit here.
For example, in the configuration shown in FIGS. 1B and 1C, a bottom portion 8v continuous along the circumferential direction of the opposed portion peripheral surface 8s of the main shaft 8 and the both ends of the bottom portion 8v are continuous over the entire circumference. The air groove 8m is provided as a rectangular groove in a longitudinal sectional view, which is formed by a pair of wall portions 8w that rise in the facing portion peripheral surface 8s direction (in the diameter increasing direction of the main shaft 8) and face each other. However, in addition to the rectangular shape in the longitudinal section, for example, a groove having a trapezoidal, curved or U-shaped profile or a bottom portion 25v is omitted and the wall portions 25w facing each other are directly continuous. Alternatively, the air groove 25g may be configured as a groove (triangular groove) having a V-shaped longitudinal section.
In the present embodiment, as an example, the pitch dimension is set to about 1.5 mm, the depth (distance S3 shown in FIG. 1 (c)) is set to about 0.05 mm, and the air groove 8m is configured. Is assumed. Note that the pitch and depth S3 need not all be constant, and either or both of the pitch and depth S3 may be set to a plurality of dimensions to form the air groove 8m.

  On the other hand, in this case, the slinger 25 is fixed to the inner wall 40s of the case 40 (for example, an interference fit), and the end surfaces of the gears G1 and G2 (the upper surfaces of FIGS. 1A and 1B (hereinafter referred to as slinger) 25c is set to a predetermined size (FIG. 1 (b)) than the end face (the upper surface in the figure (hereinafter referred to as the upper surface of the facing portion)) 8t of the facing portion 8d of the main shaft 8 on the gears G1, G2 side. It is positioned to be recessed in the axial direction (rotating blade side bearing 2 side (lower side in the figure)) by a distance S1) shown. In other words, the opposing portion 8d of the main shaft 8 is configured so that the opposing portion upper surface 8t is more geared to the gear G1, than the slinger upper surface 25c, with the slinger 25 fixed to the inner wall 40s of the case 40 (for example, interference fit). It is configured to project by a distance S1 toward the G2 side (upper side in FIG. 1B). That is, the width (axial dimension (the vertical distance in FIG. 1B)) of the facing portion 8d is the axial dimension of the inner peripheral surface 25a of the slinger 25 (that is, the thickness of the slinger 25 (shown in the figure). The distance L3)) is set larger by a predetermined dimension (distance S1).

Here, the size (protruding distance S2, width, etc.) of the facing portion 8d of the main shaft 8, the size of the meat theft, etc. may be arbitrarily set according to the size and shape of the slinger 25, and is not particularly limited. . However, the opposed portion 8 and the slinger 25 of the main shaft 8 are such that the opposed portion upper surface 8t is at least the same height as the slinger upper surface 25c in the axial direction, or the opposed portion upper surface 8t is higher in the axial direction than the slinger upper surface 25c. Needs to be positioned.
As an example, in the present embodiment, the protruding distance S2 of the facing portion 8d to the inner peripheral surface 25a of the slinger 25 is about 1.5 mm, and the protruding distance S1 of the facing portion upper surface 8t to the slinger upper surface 25c is about 1 mm. It is assumed that the size of the facing portion 8d is set (if another way of understanding is set, the size of the meat stealing is set) and the slinger 25 is positioned.

  In the configuration shown in FIG. 1B, as an example, the width of the facing portion 8d (the dimension in the axial direction (vertical direction in the figure)) is set to a predetermined dimension larger than the thickness L3 of the slinger 25. However, as long as the slinger 25 is positioned in a state where the slinger upper surface 25c is recessed by a predetermined size (as an example, the distance S1 shown in FIG. 1B) than the upper surface 8t of the opposing portion, the opposing portion 8d The width may be the same as the thickness L3 of the slinger 25, or may be smaller than the thickness L3 of the slinger 25.

  Further, in the configuration shown in FIGS. 1B and 1C, as an example, the opposed portion upper surface 8t of the opposed portion 8d is formed in a flat surface shape that does not incline in any axial direction over the entire circumference. However, the facing portion 8d may be formed in a flat surface shape in which the facing portion upper surface 8t is inclined to one side in the axial direction. Furthermore, for example, the facing portion 8d may be formed by continuously forming the facing portion upper surface 8t in a concavo-convex shape (as an example, a wave shape) along the circumferential direction.

  With such a configuration, the slinger 25 does not rotate with the main shaft 8, the inner ring 10, the drive shaft gear G1, and the main shaft gear G2, and does not rotate with them (that is, stationary) State). That is, at this time, the slinger 25 has a predetermined interval (distance L1 shown in FIGS. 1B and 1C) with respect to the opposed peripheral surface 8s of the main shaft 8 (opposed portion 8d) in a rotating state. Can be made to face each other. The slinger 25 has its inner circumferential surface 25a and slinger lower surface 25b opposed to the inner ring 10 in a rotating state with a predetermined interval, and the slinger upper surface 25c has a predetermined distance from the driving shaft gear G1 and the main shaft gear G2 in a rotating state. It can be made to oppose at intervals.

  The attachment method of the slinger 25 is not particularly limited to the interference fitting (fitting) as described above. For example, an adhesive member such as an adhesive is attached to the case according to the size, shape, and material of the slinger 25. The inner wall 40s of the case 40 may be applied and bonded, or may be attached to the inner wall 40s of the case 40 by joining by welding or the like, or fastening by a fastening member (screw or pin). Various methods may be attached in combination.

  In the configuration shown in FIG. 1B, as an example, the slinger lower surface 25b is in close contact with the side surface 12c of the outer ring 12 in a state where the slinger 25 is fixed (tightened) to the inner wall 40s of the case 40. The slinger 25 is fixed to the inner wall 40 s (for example, interference fit (fitting), joined (adhesion or welding), fastened, etc.), and the slinger 25 is not brought into close contact with the side surface 12 c of the outer ring 12 and has a predetermined They may be positioned close to each other with a gap.

  Here, the size of the slinger 25 may be arbitrarily set according to the shape of the main shaft 8 and the case 40, the size of the rotary blade side bearing 2, and the like, but the main shaft 8, the inner ring 10, the drive shaft gear G1. It is preferable that the main shaft 8, the inner ring 10, and the gears G 1 and G 2 have a maximum size in a range in which the main shaft gear G 2 and the seal 20 can smoothly rotate without contacting any of them. In other words, the slinger 25 is driven by the distance between the inner peripheral surface 25a and the opposed peripheral surface 8s of the main shaft 8 (distance L1 shown in FIGS. 1B and 1C) and the slinger upper surface 25c. It is preferable that the distance from the shaft gear G1 is set to a predetermined size so as to be as small as possible.

  In the configuration shown in FIG. 1A, the main shaft gear G2 is positioned above the drive shaft gear G1 in the extending direction of the main shaft 8 (vertical direction (vertical direction in the figure)). When setting the size of 25, it is only necessary to consider making the distance between the slinger upper surface 25c and the drive shaft gear G1 as small as possible. However, when the relative positional relationship between the drive shaft gear G1 and the main shaft gear G2 in the vertical direction is reversed, that is, when the main shaft gear G2 is positioned below the drive shaft gear G1 in the vertical direction, The size of the slinger 25 may be set so that the distance between the slinger upper surface 25c and the main shaft gear G2 is as small as possible.

  As an example, in the present embodiment, the slinger 25 has an interval L1 between the inner peripheral surface 25a and the opposed peripheral surface 8s of about 0.1 mm, and an interval between the slinger upper surface 25c and the drive shaft gear G1 is about 2 mm. Assuming that the inner and outer diameter dimensions are set, and the thickness L3 is set to about 5 mm. Further, since the slinger 25 is positioned so that the slinger lower surface 25b is substantially flush with the side surface 12c of the outer ring 12 of the rotary blade side bearing 2, the distance between the slinger lower surface 25b and the seal 20 (FIG. 1B). The distance L2) shown in FIG. 4 is substantially the same as the depth of the recess from the side surface 12c of the outer ring 12, and is about 0.25 mm.

  Since the seal 20 does not rotate with the main shaft 8, the inner ring 10, the drive shaft gear G1, and the main shaft gear G2 similarly to the slinger 25, the slinger 25 is in contact with the seal 20. It may be. In this case, the slinger 25 may be configured by setting the thickness L3 to a predetermined dimension that allows the slinger lower surface 25b to contact the seal 20. Similarly, the slinger 25 may have a shape in which the slinger lower surface 25b can come into contact with the seal 20 (for example, a shape partially protruding toward the seal 20).

  The shape of the slinger 25 is a shape that can be attached to the inner wall 40s of the case 40 with the slinger lower surface 25b in close contact with the side surface 12c of the outer ring 12, and the peripheral surface of the opposing portion between the inner peripheral surface 25a and the opposing portion 8d. There is no particular limitation as long as the distance L1 to 8s and the distance between the slinger upper surface 25c and the drive shaft gear G1 can be made as small as possible, and any shape depending on the shape of the main shaft 8 and the case 40, etc. do it.

  In the configuration shown in FIGS. 1A to 1C, as an example, the slinger upper surface 25c of the slinger 25 is formed in a flat surface shape that is not inclined in any of the axial directions over the entire circumference. May be formed in a flat surface shape in which the slinger upper surface 25c is inclined to one side in the axial direction (for example, gradually inclined upward in the axial direction as it goes in the diameter-enlarging direction). Further, for example, the slinger 25 may be formed by continuously forming the slinger upper surface 25c in a concavo-convex shape (as an example, a wave shape) along the circumferential direction.

  As in the case of setting the size of the slinger 25 described above, in the configuration shown in FIG. 1A, when setting the shape of the slinger 25, the distance from the drive shaft gear G1 should be as small as possible. You should consider it. Similarly, when the main shaft gear G2 is positioned lower than the drive shaft gear G1 in the vertical direction, the shape of the slinger 25 may be such that the distance between the slinger upper surface 25c and the main shaft gear G2 is as small as possible. .

  Further, the number of slinger 25 is not limited to one as in the configuration shown in FIGS. 1A to 1C, and may be two or more. For example, the thickness L3 of the slinger 25 is approximately half of the configuration shown in the figure (as an example, 2.5 mm), and the two slinger 25 are concentrically contacted and stacked, or at a predetermined interval. Alternatively, a multi-layered slinger assembly arranged concentrically may be used.

Here, in the above-described embodiment, the material of the slinger 25 is not particularly mentioned. However, the slinger 25 can be attached to the inner wall 40s of the case 40 with the slinger lower surface 25b in close contact with the side surface 12c of the outer ring 12. There is no particular limitation as long as it is present, and any material may be used depending on the material of the main shaft 8 and the case 40. For example, the slinger 25 may be composed of various resins such as nylon monomer, polyethylene resin, and polypropylene resin, and various elastic materials such as styrene-based and olefin-based thermoplastic elastomers, or various metal-based materials. The slinger 25 may be made of a material.
However, in consideration of lubrication for the rotary blade unit U1, it is preferable to apply various resins, elastic materials, and metal-based materials that do not cause alteration to the gear lubrication grease described later.

  In the rotary blade unit U1 configured as described above, as in the case of the conventional mower A described above, in order to rotate the cutting blade 32 stably and smoothly over a long period of time, the drive shaft gear G1 and the main shaft The gears G1, G2 and the bearing 2 are lubricated for the purpose of reducing friction and wear at the parts where the teeth of the gear G2 contact each other, preventing seizure of the rotary blade side bearing 2, and extending the fatigue life. ing.

  In this embodiment, as an example, a consistency No. defined by the National Lubricating Grease Institute (NLGI) in a predetermined space S surrounding the drive shaft gear G1 and the main shaft gear G2. 2 (consistency number 2) grease (hereinafter referred to as gear lubrication grease) is filled (enclosed) so that the volume ratio of the space S is approximately 50% or approximately 80%. ing.

  If the amount of gear lubrication grease filled (encapsulated) is too large, the softening of the grease is promoted by heat generated by stirring. On the other hand, if the amount is too small, the grease does not reach the space S sufficiently, resulting in poor lubrication. End up. For this reason, it is preferable to fill (enclose) in an amount that is approximately 30 to 90% of the space volume of the space S, and further to be filled (enclose) in an amount that is approximately 50 to 80%. ). In this case, the space volume of the space portion S is not attached to the slinger 25 (FIG. 1 (a)) as in the conventional rotary blade unit U2 (FIG. 3 (a)) by an amount corresponding to the volume of the slinger 25. It becomes smaller than the case of. On the other hand, the space volume of the space portion S is equal to the volume of the meat stealing provided on the main shaft 8 when no meat theft is provided as in the conventional rotary blade unit U2 (FIG. 3A). Larger than

  Similarly, the NLGI consistency No. is also applied to the inside of the rotary blade side bearing 2. 2 grease (hereinafter referred to as bearing lubrication grease) is filled (enclosed). In this case, the amount of filling (encapsulation) of the bearing lubrication grease may be arbitrarily set according to the purpose of use and use conditions of the rotary blade unit U1, but is approximately 25 with respect to the space volume in the rotary blade side bearing 2. It is preferable to fill (enclose) in an amount that gives a volume ratio of ˜35%.

  In addition, since the component structure of a gear lubrication grease and a bearing lubrication grease is arbitrarily set, for example according to the use purpose of the rotary blade unit U1, use conditions, etc., it does not specifically limit here. For example, the gear lubrication grease and the bearing lubrication grease may be configured as lithium soap as the thickener and mineral oil as the base oil. In this case, an extreme pressure agent may be added as an additive to the thickener and the base oil.

Here, the use state of the mower according to the present embodiment, that is, the state change of the gear lubricating grease during the operation of the rotary blade unit U1 will be described below.
The gear-lubricating grease is continuously stirred and sheared in the space S by its own weight, and the vibration caused by the rotation of the main shaft 8 and the main shaft gear G2 while the driving shaft 38 and the driving shaft gear G1 rotate. The gear lubricating grease that has been repeatedly stirred and sheared as described above rises in temperature, and is softened and thermally expanded.

At this time, the pressure (internal pressure) inside the rotary blade unit U1 (space part S) rises, so the rotary blade unit U1 against the internal air of the rotary blade unit U1 and the gear lubrication grease sealed in the space part S. The outward pressing force, specifically, the pressing force on the inner wall 40s of the case 40, the main shaft 8 and the slinger 25 acts, and the gear lubrication grease falls and contacts the opposing portion upper surface 8t and the slinger upper surface 25c. .
In this state, the slinger 25 is stationary, but on the other hand, the main shaft 8 is rotating, so that the gear lubrication grease in contact with the upper surface 8t of the facing portion and the gear lubrication grease in contact with the slinger upper surface 25c Centrifugal force generated by the rotation of the main shaft 8 and the upper surface 8t of the opposing portion acts.

  The gear lubrication grease to which the centrifugal force is applied moves above the space portion S through the inner wall 40s of the case 40, the surface of the drive shaft gear G1, and the surface of the main shaft gear G2 by the centrifugal force. Then, after the gear lubricating grease reaches the vicinity of the main shaft 8, it again falls on and comes into contact with the opposing portion upper surface 8 t and slinger upper surface 25 c of the main shaft 8 due to its own weight and vibration due to the rotation. As a result, the gear lubricating grease is circulated in the space S.

In the present embodiment, the slinger 25 is provided without making contact with the drive shaft gear G1 and the distance between the drive shaft gear G1 is reduced as much as possible (as an example, the distance between the slinger upper surface 25c and the drive shaft gear G1 is about 2 mm). Therefore, the gear lubricating grease can be easily drawn into the drive shaft gear G1. Furthermore, the gear lubrication grease drawn into the drive shaft gear G1 can be easily moved to the main shaft gear G2 via teeth that mesh with each other.
Thereby, in the space S, the flow of the gear lubrication grease can be activated (circulation is promoted), and the drive shaft gear G1 and the main shaft gear G2 do not become insufficiently lubricated, and each gear G1, G2 The teeth are also prevented from being frictioned and worn, and the gears G1, G2 can be smoothly rotated over a long period of time. As a result, the heat generation of these gears G1 and G2 can be suppressed, the deterioration of the gear lubrication grease can be prevented, and the grease can contribute to the lubrication of the drive shaft gear G1 and the main shaft gear G2 over a long period of time. .

  Further, in the present embodiment, the main shaft 8 is provided with a facing portion 8d (if another way of understanding is used, a meat stealer is provided), and the facing portion upper surface 8t of the facing portion 8d is made more than the slinger upper surface 25c of the slinger 25. Since only the distance S1 is set to the upper side in the axial direction (set to about 1 mm as an example), when the gear lubricating grease falls on the upper surface 8t of the opposing portion before falling on the slinger upper surface 25c, the opposing portion The centrifugal force generated by the rotation of the upper surface 8t is affected. For this reason, most of the gear lubricating grease circulates in contact with the upper surface 8t of the facing portion in the space S. That is, in the flow of the gear lubrication grease in the space S, the circulation flow that circulates in contact with the upper surface 8t of the opposing portion becomes the main flow, and the circulation flow that circulates in contact with the slinger upper surface 25c becomes the subflow.

  As described above, the gear lubrication grease actively flows in the space portion S during use of the mower, that is, during the operation of the rotary blade unit U1, and circulates with little contact with the slinger upper surface 25c (described above). Repeated). For this reason, the gear lubrication grease does not stay (deposit) on the slinger upper surface 25c and eventually the outer surface of the seal 20 (the surface on the side of the drive shaft gear G1 and the main shaft gear G2) and does not press the seal 20. As a result, it is possible to reliably prevent the gear lubricating grease from leaking (invading) into the rotary blade side bearing 2.

  Further, in the present embodiment, the slinger 25 is provided with the space between the facing portion peripheral surface 8s as narrow as possible without contacting the facing portion peripheral surface 8s of the facing portion 8d (as an example, facing the inner peripheral surface 25a). The distance L1 between the inner peripheral surface 25a and the opposing peripheral surface 8s is equivalent to the thickness L3 (as an example, 5 mm) of the slinger 25. The air layer Ly can be formed at a depth. In this case, the ratio of the depth (corresponding to the thickness L3 of the slinger 25) and the width (corresponding to the interval L1 between the inner peripheral surface 25a and the opposed peripheral surface 8s) of the air layer Ly is sufficiently large (for example, L3 / L1 = 50) Therefore, an air flow in the rotation direction is generated in the air layer Ly as the main shaft 8 rotates.

  For this reason, even when a pressing force is applied to the slinger 25 due to an increase in the internal pressure of the rotary blade unit U1, the pressing force is loaded by the air flow of the air layer Ly, that is, by the air flow of the air layer Ly. Thus, stress capable of resisting the pressing force can be generated, and the gear lubricating grease can be effectively prevented from entering the air layer Ly. Even when the gear lubrication grease is softened and easily flows as described above, if the air flow in the air layer Ly is longitudinally cut, the gear lubrication grease after the longitudinal cut will be the seal lip of the seal 20. There is no pressing force enough to slip through the sliding contact portion between 20l and the seal groove of the inner ring 10. Thereby, it is possible to reliably prevent the gear lubricating grease from leaking (intruding) into the rotary blade side bearing 2.

  The ratio (L3 / L1) of the depth (L3) to the width (L1) of the air layer Ly is too small (for example, the width L1 of the air layer Ly, that is, the cross-sectional area is large). The pressing force due to the internal pressure increase cannot be sufficiently applied by the air flow, and the gear lubrication grease cannot be sufficiently prevented from entering the air layer Ly. It is preferable to set as large as possible. In the present embodiment, considering the effect of preventing the gear lubricating grease from entering the air layer Ly (so-called air seal effect), as described above, the ratio (L3) of the depth (L3) to the width (L1) of the air layer Ly. / L1) is set to 50. In other words, the slinger 25 is configured such that the thickness L3 and the ratio (L3 / L1) between the inner peripheral surface 25a and the distance L1 between the opposing portion peripheral surface 8s of the opposing portion 8d are 50. In addition, it is positioned in the space S.

  In addition, in the present embodiment, the opposing portion peripheral surface 8s of the opposing portion 8d has a spiral shape (female screw structure) wound in the same direction (for example, counterclockwise) as the rotation direction of the main shaft 8. Since the air groove 8m is provided upward in the direction (from the lower side to the upper side in FIG. 1C), the air groove 8m moves from the lower side to the upper side as the main shaft 8 rotates ( A vertical upward airflow can be generated.

  In this case, the air flow is pressurized between the air groove 8m and the inner peripheral surface 25a of the slinger 25, that is, in the air layer Ly when flowing in the air groove 8m from the lower side to the upper side. The generated air flow can generate a vertical upward pressure (a resistance against a vertical downward force). As a result, a gap between the inner peripheral surface 25a of the slinger 25 and the opposed peripheral surface 8s of the main shaft 8 (opposed portion 8d) can be sealed by the air layer Ly due to the pressurized air flow (so-called Archimedes). Screw pump action).

  Therefore, even when the gear lubrication grease is softened and easily flows as described above, the gear lubrication grease has a gap between the inner peripheral surface 25a and the opposed peripheral surface 8s, that is, the air layer Ly. It is possible to prevent intrusion into the rotary blade side bearing 2, thereby reliably preventing intrusion (intrusion) into the rotary blade side bearing 2.

  Immediately after the main shaft 8 is stopped, the softened gear lubrication grease slightly enters the air layer Ly. Even in this case, the above-described screw pump operation is continued, and the gear lubrication grease is in the air. It is possible to avoid reaching the seal 20 (seal lip 20l) of the rotary blade side bearing 2 through the layer Ly. Even if the gear lubrication grease (softening grease) that has entered the air layer Ly reaches the seal 20 (seal lip 20l) of the rotary blade side bearing 2, the gear lubrication grease (softening grease) Since the temperature is lowered by the stop and returns to the original grease (semi-solid) state, it is possible to effectively prevent slipping through the sliding contact portion between the seal lip 201 and the seal groove of the inner ring 10. Thereby, it is possible to reliably prevent the gear lubricating grease from leaking (intruding) into the rotary blade side bearing 2.

  Further, as described above, according to the present embodiment, during operation of the rotary blade unit U1, the gear lubricating grease actively flows (main flow described above) in the space S and is circulated, so that the drive shaft Lubrication of the gear G1 and the main shaft gear G2 is promoted, and the gears G1 and G2 can be maintained in a good lubrication state for a long time. Furthermore, since the gear lubrication grease can be prevented from leaking (intruding) into the rotary blade side bearing 2, the rotary blade side bearing 2 is maintained in a good lubrication state for a long period of time during the operation of the rotary blade unit U1. And can continue to rotate accurately.

  Further, the slinger 25 covers the seal 20 in a state where the distance between the slinger lower surface 25b and the seal 20 is reduced as much as possible (for example, the distance L2 shown in FIG. 1B is set to approximately 0.25 mm). Therefore, the gear lubricating grease does not directly press the seal 20 and does not directly contact the sliding contact portion between the seal lip 201 of the seal 20 and the seal groove of the inner ring 10. As a result, it is possible to more effectively prevent the gear lubricating grease from leaking (invading) into the rotary blade side bearing 2.

  In addition, as described above, the seal 20 located on the drive shaft gear G1 and main shaft gear G2 side (upper side in FIG. 1B) has a pressure inside the bearing at both the outer diameter portion and the inner diameter portion. Since no through hole (a through hole corresponding to the through hole 22h formed in the seal 22) is provided to suppress the change, gear lubricating grease leaks (intrudes into) the rotary blade side bearing 2 from the through hole. However, there is no inconvenience such as mixing with bearing lubricating grease.

  As described above, according to the rotary blade unit U1 according to the present embodiment, the slinger 25 that is always stationary is provided on the gears G1 and G2 side of the rotary blade side bearing 2, and the portion facing the slinger 25 is expanded and widened. By providing the opposed portion 8d (meat stealing) on the main shaft 8 and providing a spiral air groove 8m on the opposed portion peripheral surface 8s of the opposed portion 8d, the inside thereof (for example, the space portion S and the rotary blade side) It is possible to reliably prevent leakage of the grease enclosed in the bearing 2) to the outside. As a result, the lubrication state of the rotary blade unit U1 is maintained well, and wear of the drive shaft gear G1 and the main shaft gear G2 and seizure of the rotary blade side bearing 2, the gear side bearing 4, and the drive shaft bearing 6 are prolonged. The cutting blade 32, which is a rotating member, can be stably rotated with a constant rotational accuracy over a long period of time without being generated.

Here, with respect to the mower according to the present embodiment, a predetermined test was performed and verified with respect to the leakage preventing effect of the grease enclosed in the mounted rotary blade unit U1. The test contents and test results will be described below.
In this test, five mowers (corresponding to the mower A shown in FIG. 4) are prepared as test machines, and three of these mowers include a slinger 25 and an opposing portion 8d (if another way of understanding is used). ) And a rotary blade unit (rotary blade unit U1 shown in FIG. 1 (a)) provided with an air groove 8m on the peripheral surface 8s of the opposing portion 8d is mounted, and the remaining two grass cuttings The machine was equipped with a conventional rotary blade unit (rotary blade unit U2 shown in FIG. 3 (a)) in which none of the slinger 25, the facing portion 8d (meat stealing) and the air groove 8m were provided.

  The three grass mowers provided with the slinger 25, the facing portion 8d and the air groove 8m with respect to the rotary blade unit have an inner portion of each rotary blade unit (the space portion S shown in FIGS. 1 (a) and 4 (a)). ) Was filled with a predetermined amount (9.6 g, 6.0 g and 12 g) of a predetermined lubricant (Duplex EP No. 2 (hereinafter referred to as gear lubrication grease) manufactured by Kyodo Yushi Co., Ltd.). Here, in the following description, a mower filled with 9.6 g of gear lubrication grease inside the rotary blade unit is the machine 1, the mower filled with 6.0 g is the machine 2, and a mower filled with 12 g is a comparative machine. It is called 1. In addition, these filling amounts are approximately 80% of the volume of the machine 1, the volume of 50% of the machine 2 with respect to the space volume inside the rotary blade unit (space S), and the comparison machine. 1 corresponds to a volume amount of approximately 100%.

  On the other hand, gear moisturizing grease similar to that of the machines 1 and 2 and the comparator 1 described above is also applied to the two mowers that are not provided with the slinger 25, the facing portion 8d, and the air groove 8m. A predetermined amount (10.8 g and 6.8 g) was charged. Here, in the following description, a mower filled with 10.8 g of the gear lubricating grease in the rotary blade unit is referred to as a comparator 2, and a mower charged with 6.8 g is referred to as a comparator 3. These filling amounts correspond to a volume amount of about 80% for the comparator 2 and a volume amount of about 50% for the comparator 3 with respect to the space volume inside the rotary blade unit (space portion S). .

  In this case, the space volume inside the rotary blade unit (space portion S) is smaller than that of the comparators 2 and 3 by the present machines 1 and 2 and the comparator 1 by the volume of the slinger 25. In this test, the volume of the slinger 25 is set to about 2.3 cc, and the volume (2.3 cc) corresponds to about 2.1 g in terms of the weight of the gear lubricating grease. In addition, the space volume inside the rotary blade unit (space S) is larger in the present machine 1, 2 and the comparison machine 1 than in the comparison machine 2, 3 by the volume of the meat stealing provided on the spindle. In this test, the volume of the meat theft is set to about 0.64 cc, and the volume (0.64 cc) corresponds to about 0.6 g in terms of the weight of the gear lubricating grease.

  Further, as a rolling bearing for supporting the main shaft of each rotary blade unit (the rotary blade side bearing 2 shown in FIGS. 1A and 4A), the bearing outer diameter is 32 mm, the bearing inner diameter is 12 mm, and the bearing width is set. A ball bearing set to 10 mm and fitted with a contact type rubber seal to seal the inside was used. The contact type rubber seal is not formed with a through hole (air hole) for suppressing (adjusting) the pressure change inside the bearing, and the inside of the bearing is kept almost completely sealed. Further, inside the bearing, as a lubricant, a thickening agent is lithium soap and a base oil is a mineral oil-based grease (Shell Albanian Grease S2 manufactured by Showa Shell Sekiyu KK) (hereinafter referred to as bearing lubricating grease). 4 g was enclosed.

  Fig. 2 (a) shows a test device for verifying the grease leakage prevention effect of the rotary blade unit mounted on the mower. Using this test device, the machine 1, 2 and the comparator 1 , 2, and 3 are operated for a predetermined time at a predetermined speed (rotational speed of the cutting blade) under predetermined conditions, respectively, and then the gear lubrication grease enclosed in the rotary blade unit and the rolling bearing (rotary blade side bearing) ) The grease leakage prevention effect of the rotary blade unit for these mowers was verified by comparing the leakage state of the bearing lubricating grease sealed inside.

  As shown in FIG. 2 (a), the test apparatus has a rectangular parallelepiped box shape, and angle steel is used as the frame material, and each surface portion surrounded by the frame material is an expanded metal. It is configured. Then, the test apparatus is fastened and fixed to the gantry with bolts, and the operation tube 30 and the operation handle 36 (see FIG. 4) of the mower are in the test apparatus so that the mower is suspended in the test apparatus. It was fixed with a string to the frame material.

  In the test, the atmospheric temperature of the mower (the machine 1, 2 and the comparator 1, 2, 3) under test is kept at room temperature, and in this state, the cutting blade is rotated at 8000 revolutions per minute, The machine 1, 2 and the comparator 1, 2, 3 were each operated continuously for a maximum of 30 hours. At that time, fuel was supplied to the engine 34 (see FIG. 4) at a predetermined timing, and the machines 1, 2 and the comparators 1, 2, 3 were continuously operated. After that, remove the rotary blade unit from this machine 1, 2 and comparator 1, 2, 3, and grease leaked from the inside of the rolling bearing (rotary blade side bearing) (bearing lubrication grease or bearing lubrication grease and gear lubrication grease) (Hereinafter, these leaked greases are simply referred to as grease) and collected with a spatula (small spoon), and the leakage amount is measured for the machine 1, 2 and the comparators 1, 2, 3 Each was measured and compared. In this test, the operation of the above mower (the machine 1, 2 and the comparator 1, 2, 3) and the measurement of the amount of grease leakage were taken as one test cycle, and the test cycle was repeated twice. Each was compared.

  FIG. 2 (b) shows the results of each test. As is apparent from FIG. 2 (b), in the case of the comparators 2 and 3 not provided with the slinger 25, the facing portion 8d and the air groove 8m, the rolling bearings are used. The amount of grease leakage from the (rotary blade side bearing) is 4 g or more at the time when 12 hours have elapsed before the operation time reaches 30 hours in the comparator 2 and at the time when 15 hours have elapsed in the comparator 3, both being 4 g or more. A large amount of grease (more than 10 times) leaked from the amount enclosed (approximately 0.4 g). That is, it was verified that the gear lubricating grease leaked (invaded) inside the bearing was mixed with the bearing lubricating grease and further leaked outside the bearing. In this case, the leaked grease reaches the cutting blade, and the test is stopped when the operation time of the comparator 2 is 12 hours and the operation time of the comparator 3 is 15 hours. did.

On the other hand, in the case of the machines 1 and 2 provided with the slinger 25, the facing portion 8d, and the air groove 8m, the amount of grease leakage from the rolling bearing (rotating blade side bearing) is after the operating time has passed 30 hours. However, it is 0.02 to 0.07 g, which is only about 5 to 17% of the amount of bearing lubrication grease enclosed in the bearing (about 0.4 g), and the amount of grease leakage of the comparators 2 and 3 ( 4g or more) was only about 0.5 to 1.7%.
The amount of grease leakage relative to the amount of gear lubrication grease filled in the rotary blade unit (space S) is about 0.3 to 0.7% in the case of the machine 1, and 0.3 in the case of the machine 2. It was only about 0.5%.

  However, even in the case of the mowing machine provided with the slinger 25, the facing portion 8d and the air groove 8m, in the case of the comparison machine 1, the amount of grease leakage from the rolling bearing (rotating blade side bearing) is 30 hours. It reached 4g or more at the time of 10 hours before it reached, and the leakage amount was the same as the above-mentioned comparators 2 and 3. For this reason, the test was stopped when the operating time passed 10 hours.

As described above, like the rotary blade unit U1 according to the present embodiment, the slinger 25 is provided, and the opposing portion 8d (meat stealing) in which the opposing portion to the slinger 25 is expanded and widened is provided on the main shaft 8, and the opposing portion Leakage of grease (gear lubrication grease and bearing lubrication grease) sealed inside the rotary blade unit U1 (space portion S) by providing a spiral air groove 8m on the opposed peripheral surface 8s of the portion 8d It has been verified by the above-described test that the cutting blade 32, which is a rotating member, can be stably rotated with a constant rotational accuracy over a long period of time.
Further, the amount of gear lubrication grease filled in the rotary blade unit (space S) is approximately 50 to 80% of the volume of the space inside the rotary blade unit (space S). The optimal amount was verified by the test described above.

It is a figure which shows the structural example of the rotary blade unit which concerns on one Embodiment of this invention, Comprising: (a) is sectional drawing, (b) is the slinger provided in the rotary blade side bearing, the opposing part of a main shaft, and an air groove Sectional drawing which shows the example of a structure, (c) is a conceptual diagram for demonstrating the structure of the air groove which comprises spiral. It is a figure for demonstrating the test about the leakage prevention effect of the grease enclosed inside the rotary blade unit mounted in the mower, Comprising: (a) is a figure which shows the example of whole structure of a test apparatus, (b) FIG. 6 is a diagram showing test results for the present machine and the comparator. It is a figure which shows the structural example of the conventional rotary blade unit, (a) is sectional drawing, (b) is sectional drawing which shows the structural example of a rotary blade side bearing. The perspective view which shows the example of whole structure of the conventional mower.

Explanation of symbols

2 Rotary blade side bearing 4 Gear side bearing 8 Main shaft 8d Opposing part 8m Air groove 8s Opposing part peripheral surface 8t Opposing part upper surface 20, 22 Seal 25 Slinger 25a Slinger inner peripheral surface 32 Cutting blade 34 Engine 38 Drive shaft 40 Case 40s Case inner wall A Mowing machine G1 Drive shaft gear G2 Main shaft gear L1 Slinger inner peripheral surface-opposing portion peripheral surface distance L2 Slinger lower surface-seal distance L3 Slinger thickness Ly Air layer S Space portion S1 Opposing portion widening distance S2 Opposing portion protruding distance S3 Air groove depth Ly Air layer U1 Rotary blade unit

Claims (4)

A plurality of rolling bearings which are provided with a main shaft extending in a predetermined direction, a stationary wheel and a rotary wheel which are opposed to each other so as to be relatively rotatable, and rotatably support the main shaft, and are rotated by a driving device. In order to transmit the rotational force of the drive shaft to the main shaft, at least one set of gears which are respectively provided on one end side of the drive shaft and the main shaft and mesh with each other, and a rotating member attached to the other end side of the main shaft; A rotating member support unit comprising the main shaft, a rolling bearing and a case for housing a gear;
In order to prevent foreign matter from entering the rolling bearing disposed at least closest to the rotating member, an annular slinger is provided in close contact with or close to the side surface of the stationary ring on the gear side. The slinger is positioned so that its inner peripheral surface is opposed to the main shaft at a predetermined interval, and is positioned so that both the rotating ring of the rolling bearing and the gear are not in contact with each other. The main shaft is configured to expand at least a portion facing the inner peripheral surface of the slinger toward the inner peripheral surface of the slinger rather than the outer periphery of the main shaft. Is a rotary member support unit characterized in that an air groove is provided continuously in a concave shape over the entire circumference.   The air groove is formed in a spiral shape continuous from the rolling bearing side disposed closest to the rotating member toward the gear side, and the spiral is wound in the same direction as the rotation direction of the main shaft. The rotating member support unit according to claim 1, wherein the rotating member support unit is configured.   In the rolling bearing disposed closest to the rotating member, at least a pair of sealing members forming an annular shape for sealing the inside thereof are interposed between the stationary wheel and the rotating wheel with the rolling element interposed therebetween, The slinger is fixed to the inner wall of the case, the end surface on the rolling bearing side is in close contact with the side surface on the gear side of the stationary ring, and is opposed to the sealing member with a predetermined interval. 3. On the other hand, the end face on the gear side is positioned to be recessed in the axial direction by a predetermined amount from the end face on the gear side opposite to the main shaft. The rotating member support unit described.   The rotating member support unit according to any one of claims 1 to 3, wherein a cutting blade is attached to the main shaft as a rotating member for cutting away vegetation growing on the ground surface from the vicinity of the root.

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