JP2009028884A - Rotary member supporting unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary member supporting unit capable of preventing grease from leaking outside by always maintaining its internal pressure at the approximately same pressure and stably rotating a rotary member at fixed rotary accuracy for a long period. <P>SOLUTION: In the rotary member supporting unit U1, in which an internal pressure adjusting mechanism for maintaining its internal pressure at the approximately same pressure is provided, having a main spindle 8, a plurality of bearings 2, 4 for supporting the main spindle, at least one set of gears G1, G2 for transmitting rotary force of a drive shaft 38 to the main spindle, and the rotary member 32, an internal pressure adjusting chamber 20 for opening the inside of the internal pressure adjusting chamber to the rotary member supporting unit only and capable of collecting and accumulating a lubricant is arranged as the internal pressure adjusting mechanism, the internal pressure adjusting chamber is formed so as to expand and contract its capacity, and at least one connection hole for connecting with the inside of the rotary member supporting unit is provided. When the internal pressure in the unit rises, the capacity of the internal pressure adjusting chamber capacity is expanded by making air in the unit flow into the internal pressure adjusting chamber. When the internal pressure in the unit is reduced, the capacity of the internal pressure adjusting chamber is contracted by making the air in the internal pressure adjusting chamber flow into the unit. Consequently, the pressure in the unit is always adjusted at an approximately constant state. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to, for example, a grass cutter, a brush cutter and a lawn mower used for cutting off a plant growing on the ground surface (e.g., lawn or weed) 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.

FIGS. 5A and 5B show 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. Note that a gear (referred to as 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.

  Further, the rotary blade unit U2 includes a main shaft 8 extending in a predetermined direction, and two rolling bearings (hereinafter referred to as the rotary blade side bearing 2 (FIG. 5B)) that rotatably support the main shaft 8. In order to transmit the rotational force of the drive shaft 38 to the main shaft 8 (on the lower side bearing) and the gear side bearing 4 (upper bearing in the figure). A pair of gears (referred to as drive shaft gear G1 (right side gear in the figure) and main shaft gear G2 (left side gear in the figure)) provided on the left end side and the upper end side in FIG. And a rotatable rotating member (cutting blade) 32 attached to the other end side of the main shaft 8 (lower end side in the figure).

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. 5B). Further, the operation tube 30 is provided with a protective cover 42 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.

  Further, for example, as the rotary blade side bearing 2, a sealed ball bearing in which a contact type rubber seal (not shown) is interposed between the inner and outer rings and balls are incorporated between the inner and outer rings as rolling elements is applied. In order to lubricate the rotary blade side bearing 2, as an example, a grease composed of lithium soap as a thickener and mineral oil as a base oil (hereinafter referred to as bearing lubrication grease) is enclosed inside the bearing. ing. In this case, as an example, the rubber seal (not shown) has an outer diameter portion fixed to the outer ring of the rotary blade side bearing 2 and an inner diameter portion (lip portion) formed on the inner ring of the rotary blade side bearing 2. It is positioned so as to be in sliding contact with the seal groove (not shown).

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 only passed through a rubber seal (a seal (not shown) located on the gears G1 and G2 side). And is always in contact with the 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 accumulates on the outer surface (surface on the gears G1, G2 side) of a rubber seal (not shown) located on the gears G1, G2 side by its own weight, and presses the seals. In addition, the outer surface of the rubber seal (not shown) in which 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. A large amount is deposited on the (gear G1, G2 side surface), and the seal is pressed.

Then, when the rubber seal (not shown) is continuously pressed by the gear lubrication grease, the gear lubrication grease is transferred from the sliding contact portion between the lip portion of the seal and the seal groove of the rotary blade side bearing 2 as a result. Leakage (intrusion) may occur inside the bearing 2.
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 and 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 lip portion of the rubber seal (seal (not shown) located on the cutting blade 32 side) of the rotary blade side bearing 2 and the seal groove (not shown) of the rotary blade side bearing 2 are generated. The grease may leak out of the rotary blade side bearing 2 from a sliding contact portion or an air hole (not shown) provided in the seal. In this case, for example, leaked grease adheres to the cutting blade 32 (the state of the grease Gb in FIG. 5B), and not only there is a possibility that the temperature will rise abnormally due to an increase in rotational torque due to viscous resistance. There is also a possibility of adversely affecting the soil.

  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 in order to solve such a problem. The purpose of the present invention is to keep the internal pressure at a substantially constant pressure, thereby preventing leakage of grease enclosed inside to the outside, and a rotating member. An object of the present invention is to provide a rotating member support unit that can be stably rotated with a constant rotational accuracy over a long period of time.

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, a plurality of rolling bearings that rotatably support the main shaft, and a drive device. In order to transmit the rotational force of the driven drive shaft to the main shaft, at least one set of gears provided on one end side of the drive shaft and the main shaft and meshing with each other, and a rotation attached to the other end side of the main shaft And an internal pressure adjusting mechanism for always maintaining the internal pressure at a substantially constant pressure.
In such a rotating member support unit, an internal pressure adjusting chamber is provided as an internal pressure adjusting mechanism, in which the inside is opened only to the rotating member supporting unit, and the lubricant enclosed in the unit can be collected and accumulated. ing. In this case, the internal pressure adjusting chamber is configured so that its volume can be expanded and contracted, and has at least one communication hole that communicates with the inside of the rotating member support unit. When rising, the internal air of the unit is introduced from the communication hole to increase the volume, and when the internal pressure is reduced, the internal air of the internal pressure adjusting chamber is discharged from the communication hole to the unit to reduce the volume, The internal pressure of the unit is always adjusted to a substantially constant pressure.

  As an example, the internal pressure adjustment chamber may have an elastic structure that can be expanded and contracted in a predetermined direction. In this case, when the internal pressure of the rotating member support unit increases, the internal pressure adjustment chamber expands in the predetermined direction, thereby increasing its volume. In addition, when the internal pressure of the unit decreases, the volume may be reduced by shortening the unit with respect to the predetermined direction.

  In addition, as an internal pressure adjusting mechanism, the inside of the rotating member support unit is opened to the outside, allowing the inside air of the unit to flow out to the outside of the unit and allowing the outside air of the unit to flow into the unit. An internal pressure adjusting hole may be formed. The internal pressure adjusting hole includes a main shaft through hole penetrating through the main shaft along the extending direction of the main shaft and a fastening member through hole penetrating the main shaft through hole along the axis of the fastening member. When the internal pressure of the rotating member support unit increases, the inside air of the unit flows into the main shaft through hole and the fastening member through hole, and flows out to the outside of the unit through these through holes. When the internal pressure decreases, the inside air of the main shaft through hole and the fastening member through hole flows out into the unit, and the outside air of the unit flows into the unit through the through hole, thereby The internal pressure is always adjusted to a substantially constant pressure.

  In this case, a fastening hole for fastening the fastening member is formed in the main shaft at a predetermined depth from the other end, and the main shaft through hole penetrates the main shaft from the one end to the fastening hole. By fastening the fastening member in the fastening hole, the main shaft through hole and the fastening member through hole are communicated, and the inside of the rotating member support unit is open to the outside.

In addition to the main shaft through hole and the fastening member through hole, the main shaft has a main shaft branch hole branched from the main shaft through hole and extending radially in the radial direction and opening on the outer peripheral surface of the main shaft. May be formed as an internal pressure adjusting hole.
In this case, the main shaft branch hole is branched from the main shaft through hole so that the opening on the outer peripheral surface of the main shaft is positioned in the vicinity of the gear provided on the drive shaft, and is radially formed along the radial direction of the main shaft. At least one of them may be extended.

  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 internal pressure can always be maintained at a substantially constant pressure. As a result, leakage of the grease enclosed in the inside to the outside can be prevented and the rotating member can be kept constant over a long period of time. The rotation accuracy can be kept stable with the rotation accuracy.

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, a configuration similar to that of the above-described conventional mower A (FIG. 5A) is assumed as an example. Furthermore, 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. 5B) described above, the same or similar configuration as the rotary blade unit U2 is described. Are denoted by the same reference numerals in the drawings, and the description thereof is omitted or simplified.

  1A and 1B show a rotary blade unit U1 (rotary member support unit) of a mower according to the first embodiment of the present invention. The rotary blade unit U1 has a predetermined direction. , A plurality of rolling bearings 2 and 4 that rotatably support the main shaft 8, and a rotational force of a drive shaft 38 that is rotated by a drive device (see the engine 34 (see FIG. 5A)). At least one set of gears G1, G2 provided on one end side (the left end side and the 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 of the main shaft 8 (the lower end side in FIG. 1A) is provided.

The main shaft 8, the rolling bearings 2 and 4, and the gears G 1 and G 2 are respectively accommodated in a predetermined case 40 having a cylindrical shape, and the cutting blade 32 is a main shaft 8 by a fastening member (for example, a bolt) 50. And fixed 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).

  In the configuration shown in FIG. 1A, the rotary blade unit U1 includes, as an example, two rolling bearings (rotary blade side bearing 2 (lower bearing in the figure) and gear side bearing 4 (upper side in the 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 to rotatably support the main shaft 8. Yes. 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). At this time, the rotary blade side bearing 2 is configured so that the rotary wheel is sandwiched between the cutting blade pressing cover 18 fitted on the main shaft 8 and the stepped portion 8g formed on the main shaft 8. It is positioned in the extending direction (that is, the vertical direction (the vertical direction 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 change the direction of the rotational force generated from the engine 34 (FIG. 5A) and reduce the speed of the cutting blade 32 attached to the main shaft 8. , And functions as 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, the rotary blade unit U1 that is a rotary member support unit is provided with an internal pressure adjusting mechanism for keeping the internal pressure of the rotary blade unit U1 at a substantially constant pressure. In this case, as such an internal pressure adjusting mechanism, the inside is opened only to the rotary blade unit U1 (that is, sealed inside other than the rotary blade unit U1), and the lubricant enclosed in the rotary blade unit U1 is captured. An internal pressure adjusting chamber 20 capable of collecting and accumulating is provided.

  The internal pressure adjusting chamber 20 is configured so that its volume can be expanded and contracted, and has at least one communication hole 20h communicating with the inside of the rotary blade unit U1, and when the internal pressure of the rotary blade unit U1 increases. The internal pressure of the rotary blade unit U1 is adjusted to a substantially constant pressure by increasing the volume by flowing the internal air of the rotary blade unit U1 through the communication hole 20h. On the other hand, when the internal pressure of the rotary blade unit U1 decreases, the internal pressure of the internal pressure adjusting chamber 20 flows out from the communication hole 20h to the rotary blade unit U1 to reduce the volume, thereby reducing the internal pressure of the rotary blade unit U1 to a substantially constant pressure. It is adjusting. That is, the internal pressure adjusting chamber 20 constantly adjusts the internal pressure of the rotary blade unit U1 to a substantially constant pressure by expanding and contracting its volume.

  In the configuration shown in FIG. 1B, as an example, the internal pressure adjusting chamber 20 has a predetermined substantially cylindrical space inside, and its outer shape forms a substantially cylindrical bellows structure. One is provided externally (substantially directly above the extending direction of the main shaft 8 (vertical direction in FIG. 1A)). Specifically, the maximum diameter portion 20v that maximizes the outer diameter and the inner diameter, and the minimum diameter portion 20u that minimizes the outer diameter and the inner diameter are alternately and continuously provided along the circumferential direction of the internal pressure adjusting chamber 20. And the whole structure is comprised in the shape of a bellows.

  In addition, since the magnitude | size and number of the internal pressure adjustment chamber 20 are arbitrarily set according to the magnitude | size of the rotary blade unit U1, etc., for example, it does not specifically limit here. For example, in the configuration shown in FIGS. 1A and 1B, the internal pressure adjusting chamber 20 has, as an example, an inner diameter of the minimum diameter portion 20u (a distance d1 in the horizontal direction in FIGS. 1A and 1B) of 40 mm. The inner space in the form of a substantially cylindrical bellows with a normal inner height (the inner height when the volume is not enlarged or reduced (the distance h in the vertical direction in FIGS. 1A and 1B)) is 20 mm. Assume that you have one. Two or more internal pressure adjusting chambers 20 may be provided for the rotary blade unit U1.

  Further, as an example, the internal pressure adjusting chamber 20 has both ends (the upper end and the lower end of FIG. 1B) as the minimum diameter portion 20u, and a total of 5 from the minimum diameter portion 20u on one end side to the minimum diameter portion 20u on the other end side. One minimum diameter portion 20u and four maximum diameter portions 20v are alternately and continuously provided in the circumferential direction. In this case, the adjacent minimum diameter portion 20u and the maximum diameter portion 20v increase the diameter of the internal pressure adjusting chamber 20 gradually from the minimum diameter to the maximum diameter, and gradually increase the maximum diameter to the minimum diameter. Are connected to each other by being reduced to Note that the adjacent minimum diameter portion 20u and the maximum diameter portion 20v may be connected to each other in a concave shape, a convex shape, a continuous wave shape, or the like instead of a flat shape.

  Here, the size of the minimum diameter portion 20u and the maximum diameter portion 20v, the diameter difference thereof, and the number of these arrangements are not particularly limited. For example, the minimum diameter portion 20u and the maximum diameter portion 20v are arbitrarily set according to the size of the internal pressure adjusting chamber 20 or the like. do it. However, in the present embodiment, the sizes of the minimum diameter portion 20u and the maximum diameter portion 20v so that the normal volume of the internal pressure adjustment chamber 20 (the volume in a state where the internal pressure adjustment chamber 20 is not expanded or reduced) is about 20 cc. A case where the diameter difference and the number of these arrangements are set is assumed as an example.

  By configuring the internal pressure adjusting chamber 20 in a bellows shape in this way, the internal pressure adjusting chamber 20 is arranged in a predetermined direction (for example, in this embodiment, the extending direction of the main shaft 8 (FIGS. 1A and 1B)). The elastic structure can be expanded and contracted with respect to the vertical direction). That is, the internal pressure adjusting chamber 20 expands with respect to the extending direction of the main shaft 8 (the vertical direction in FIGS. 1A and 1B, hereinafter referred to as the height direction of the internal pressure adjusting chamber), thereby expanding its volume. On the other hand, the volume can be reduced by shortening with respect to the height direction of the internal pressure adjusting chamber. Thereby, the internal pressure adjusting chamber 20 can be configured such that its volume can be expanded and contracted.

  In the configuration shown in FIGS. 1 (a) and 1 (b), the internal pressure adjusting chamber 20 has, as an example, both an external shape and an internal shape that are substantially cylindrical. It is not limited to. For example, while having a predetermined substantially conical space inside, the outer shape may be formed in a substantially conical shape, or having a predetermined substantially rectangular space inside, and the outer shape is also formed in a substantially rectangular shape. May be. Further, the inner shape (the shape of the predetermined space inside) and the outer shape of the internal pressure adjusting chamber 20 may be different.

  Further, the internal pressure adjusting chamber 20 may not have the bellows structure as long as the volume thereof can be expanded and contracted. For example, the internal pressure adjusting chamber 20 includes a minimum diameter portion 20u and a maximum diameter portion 20v one by one from one end side to the other end side in the height direction of the internal pressure adjusting chamber (for example, in FIGS. 1 (a) and 1 (b)). (From the upper end to the lower end), a structure (so-called spring structure) continuously provided spirally along the circumferential direction, thereby expanding and contracting the height of the internal pressure adjustment chamber (the vertical distance in the figure, the same applies hereinafter) It may be configured to be freely adjustable in volume. Alternatively, the internal pressure adjusting chamber 20 is a sphere or an elliptical sphere (the outer internal shape is a sphere or an elliptical sphere), and not only the height of the internal pressure adjusting chamber can be expanded but also the overall diameter can be expanded and contracted (so-called balloon structure). ), The volume may be increased or decreased.

  Here, as the material of the internal pressure adjusting chamber 20, any material can be applied as long as the volume can be expanded and contracted. For example, what is necessary is just to comprise the internal pressure adjustment chamber 20 with various resin materials, and in this embodiment, the case where the internal pressure adjustment chamber 20 is a product made from polyethylene is assumed as an example. However, in consideration of the temperature rise of the rotary blade unit U1 accompanying the rotation of the rotary blade 32, a resin material having a melting point of 110 ° C. or higher is used because it does not cause deformation or alteration even at high temperatures (eg, 110 ° C. or higher). It is preferable to apply as the material. Further, in consideration of lubrication for the rotary blade unit U1, it is preferable to apply a resin material that does not change the quality of the gear lubrication grease described later as the material.

  Furthermore, in the configuration shown in FIGS. 1A and 1B, the internal pressure adjusting chamber 20 is, for example, substantially above the upper portion of the case 40 (extending direction of the main shaft 8 (vertical direction in FIG. 1A)). However, the position is not limited to this. For example, the side surface of the case 40 (horizontal direction with respect to the extending direction of the main shaft 8 (the left-right direction in FIG. It may be provided outside the left side surface)) in the figure.

  In the internal pressure adjusting chamber 20, a mounting portion 20s for mounting the internal pressure adjusting chamber 20 to the rotary blade unit U1 is provided in a portion facing the case 40, and the outer diameter of the mounting portion 20s is adjusted to the internal pressure. The chamber 20 has a concentric cylindrical shape smaller than the inner diameter of the minimum diameter portion 20u. Note that the mounting portion 20s is positioned with respect to the internal pressure adjusting chamber 20 so that a part (the protruding portion 20d) protrudes toward the case 40 side.

  Here, since the size, shape, position, protrusion length to the case 40 side, and the like of the mounting portion 20s are arbitrarily set according to the size of the rotary blade unit U1 and the internal pressure adjustment chamber 20, for example, There is no particular limitation here. For example, the attachment portion 20s may have an eccentric columnar shape with respect to the internal pressure adjusting chamber 20, or may have a conical shape, a rectangular shape, or the like. For example, the mounting portion 20s extends the protruding portion 20d to the inside (internal space) side of the internal pressure adjusting chamber 20 by a predetermined length, and a part of the mounting portion 20s (projecting portion 20d) toward the case 40 side. While projecting, the other part (the extended part) may be positioned with respect to the internal pressure adjusting chamber 20 so as to protrude toward the inside (internal space) of the internal pressure adjusting chamber 20.

  Further, in the present embodiment, the attachment portion 20s penetrates from one end side (the upper end side in FIG. 1B) to the other end side (the lower end side in FIG. 1), and the inside of the rotary blade unit U1 (see FIG. At least one communication hole 20h communicating with the predetermined space S) surrounding the drive shaft gear G1 and the main shaft gear G2 in 1 (a) is formed. As an example, in the configuration shown in FIG. 1B, with respect to the mounting portion 20s, from one end side (the upper end side in FIG. 1B) to the other end side (the lower end side in FIG. 1B). Only one communication hole 20h is formed as a concentric hole penetrating therethrough.

  Note that the size, shape, length, position, number, and the like of the communication hole 20h are arbitrarily set according to, for example, the size of the internal pressure adjusting chamber 20, the length of the mounting portion 20s, and the like. do not do. For example, in the configuration shown in FIG. 1B, it is assumed that the communication hole 20h is formed as a circular hole having a cylindrical shape with a diameter (distance d2 in the left-right direction in FIG. 1B) of 1 mm. .

  Further, the communication hole 20h may be formed by an arbitrary method according to, for example, the material or length of the mounting portion 20s. For example, after forming the internal pressure adjusting chamber 20 provided with the attachment portion 20s, the communication hole 20h may be formed by performing a predetermined drilling process on the attachment portion 20s. Alternatively, a predetermined metal attachment portion 20s may be formed separately from the internal pressure adjusting chamber 20 by forging or casting, and the communication hole 20h may be formed simultaneously with the formation of the attachment portion 20s. In this case, the mounting portion 20s may be fixed to the internal pressure adjusting chamber 20 by joining by bonding or welding, fastening by a fastening member (screw, pin or the like), or the like.

  Furthermore, for example, two or more communication holes 20h may be formed in the mounting portion 20s, and the communication holes 20h may be conical holes or rectangular holes.

  In any case, a predetermined spiral groove (for example, male screw portion 20m) is formed on the outer peripheral surface of the protruding portion 20d toward the case 40 in the mounting portion 20s. On the other hand, the case 40 is provided with a circular hole 40h whose inner diameter is substantially the same as the outer diameter of the mounting portion 20s at a portion facing the internal pressure adjusting chamber 20 (upper part of FIG. 1A). A predetermined spiral groove (for example, a female screw portion (not shown)) that is screwed with the spiral groove (male screw portion 20m) of the mounting portion 20s is formed on the inner peripheral portion of the circular hole 40h. Yes. The mounting portion 20 s (internal pressure adjusting chamber 20) can be fastened and fixed to the case 40 by screwing both the spiral grooves (the male screw portion 20 m and the female screw portion).

  Thereby, the inside (space part S) of rotary blade unit U1 and the inside of the internal pressure adjustment chamber 20 can be connected only through the communication hole 20h.

The pitch and depth of the male screw portion 20m formed in the mounting portion 20s and the female screw portion (not shown) formed in the circular hole 40h of the case 40 are, for example, the size of the rotary blade unit U1 and the internal pressure adjusting chamber 20 Since it is arbitrarily set according to the outer diameter of the mounting portion 20s, it is not particularly limited here. For example, in the configuration shown in FIG. 1B, the external thread portion 20m of the mounting portion 20s has, for example, an outer diameter (peak height) of 5 mm, an inner diameter (valley depth) of about 4 mm, and a pitch of 0.1 mm. A case where an 8 mm spiral groove is formed is assumed. In this case, the female screw portion of the case 40 is configured as a spiral groove set to an outer diameter, an inner diameter, and a pitch dimension that can be screwed with the male screw portion 20m.
Further, the fixing method of the internal pressure adjusting chamber 20 and the case 40 is not limited to fastening and fixing, for example, the mounting portion 20s of the internal pressure adjusting chamber 20 may be internally fitted and fixed to the circular hole 40h of the case 40. Alternatively, it may be fixed by bonding or welding.

Thus, by providing the internal pressure adjusting chamber 20 with respect to the rotary blade unit U1, the inside of the rotary blade unit U1 and the internal pressure adjusting chamber 20 are communicated with each other by the communication hole 20h. The internal pressure and the internal pressure of the internal pressure adjusting chamber 20 are maintained at a substantially constant pressure.
When the inside of the rotary blade unit U1 is pressurized from this state, the internal pressure of the rotary blade unit U1 rises, and a pressure difference is generated between the internal pressure of the internal pressure adjustment chamber 20, the inside air of the rotary blade unit U1 ( Hereinafter, such inside air is referred to as unit inside air) and flows into the internal pressure adjusting chamber 20 through the communication hole 20h. At this time, the inside of the internal pressure adjusting chamber 20 is pressurized. On the other hand, the internal pressure of the unit that has flowed in causes the internal pressure adjusting chamber 20 to extend the height of the internal pressure adjusting chamber by a predetermined size, and to increase the volume of the internal pressure adjusting chamber 20. Increase the size corresponding to the extension of the adjustment chamber height.

  As a result, the increase in the internal pressure of the internal pressure adjustment chamber 20 due to the inflow of the unit internal air from the rotary blade unit U1 to the internal pressure adjustment chamber 20 can be absorbed and canceled by the expansion of the volume of the internal pressure adjustment chamber 20. That is, it is possible to suppress the internal pressure of the internal pressure adjusting chamber 20 from continuing to increase, thereby suppressing the internal pressure of the rotary blade unit U1 from continuing to increase and maintaining the internal pressure at a substantially constant pressure (for example, The pressure can be adjusted to substantially the same pressure as the atmospheric pressure).

  On the other hand, from the state in which the internal pressure of the rotary blade unit U1 and the internal pressure of the internal pressure adjustment chamber 20 are maintained at a substantially constant pressure, the internal pressure of the rotary blade unit U1 is reduced, the internal pressure of the rotary blade unit U1 is reduced, and the internal pressure is adjusted. When a pressure difference is generated between the internal pressure of the chamber 20 and the internal pressure of the internal pressure adjustment chamber 20 (hereinafter, this internal air is referred to as adjustment internal air) flows out into the rotary blade unit U1 through the communication hole 20h. . At this time, the inside of the internal pressure adjusting chamber 20 is depressurized. On the other hand, the internal pressure adjusting chamber 20 shortens the height of the internal pressure adjusting chamber by a predetermined size by the outflowing adjusting chamber air, and the volume is reduced to the internal pressure. Reduce the size corresponding to the shortening of the adjustment chamber height.

  As a result, the decrease in the internal pressure of the internal pressure adjustment chamber 20 due to the outflow of the adjustment chamber air from the internal pressure adjustment chamber 20 to the rotary blade unit U1 can be absorbed and canceled by reducing the volume of the internal pressure adjustment chamber 20. That is, it is possible to suppress the internal pressure of the internal pressure adjusting chamber 20 from continuing to decrease, thereby suppressing the internal pressure of the rotary blade unit U1 from continuing to decrease and maintaining the internal pressure at a substantially constant pressure (for example, The pressure can be adjusted to substantially the same pressure as the atmospheric pressure).

  In addition, when the inside of the rotary blade unit U1 shifts from the pressurized state to the reduced pressure state, and also when the inside of the rotary blade unit U1 shifts from the reduced pressure state to the pressurized state, the rotation is similarly performed by the expansion / contraction of the internal pressure adjusting chamber 20 described above. The internal pressure of the blade unit U1 can always be kept at a substantially constant pressure (for example, adjusted to substantially the same pressure as the atmospheric pressure).

  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 For the purpose of reducing friction and wear at the portions where the teeth of the gear G2 are in contact with each other, preventing seizure of the rotary blade side bearing 2, the gear side bearing 4 and the drive shaft bearing 6 and extending the fatigue life, etc. , G2, and the bearings 2, 4, and 6 are lubricated.

In the present embodiment, as an example, the American Grease Association (NLGI) is provided inside the rotary blade unit U1 (a predetermined space S surrounding the drive shaft gear G1 and the main shaft gear G2).
Consistency No. specified by the Lubricating Grease Institute) 2 (Consistency No. 2) grease (hereinafter referred to as gear lubrication grease) is filled (enclosed) so that the volume ratio of the space S is approximately 70% to 100%. . Similarly, the NLGI consistency No. is also applied to the inside of the rolling bearings (the rotary blade side bearing 2, the gear side bearing 4, and the drive shaft bearing 6). Two greases (hereinafter referred to as bearing lubrication greases) are filled (enclosed) so as to have a volume ratio of approximately 25% with respect to the space volume in each of the bearings 2, 4, 6.

  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, for example, as a thickener with lithium soap and a base oil as mineral 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 by 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, since the pressure (internal pressure) in the rotary blade unit U1 (space S) increases, a pressure difference is generated between the internal pressure and the internal pressure in the internal pressure adjusting chamber 20. In this case, the pressing force toward the outside of the rotary blade unit U1 against the internal air of the rotary blade unit U1 and the gear lubricating grease sealed in the space S, specifically, the inner wall 40s of the case 40 and the rotary blade bearing The pressing force to 2 acts.

  In the present embodiment, since the internal pressure adjusting chamber 20 is provided in the rotary blade unit U1, even if the pressing force as described above is applied to the gear lubricating grease sealed in the space S, The gear lubrication grease can be collected by flowing into the internal pressure adjusting chamber 20 through the communication hole 20h together with the inside air of the unit (see the arrow in FIG. 1B). Thereby, it is possible to prevent the gear lubrication grease from being continuously pressed against the rotary blade bearing 2 and leaking (invading) into the inside thereof. Note that the gear lubricating grease collected in the internal pressure adjusting chamber 20 is not agitated and sheared, and its temperature decreases and becomes semi-solid.

  In this case, the unit internal air that has flowed into the internal pressure adjusting chamber 20 expands the internal pressure adjusting chamber 20 in the direction in which the height of the internal pressure adjusting chamber is increased (the upward direction in FIGS. 1A and 1B). To enlarge. On the other hand, the gear lubricating grease collected and semi-solidified inside the internal pressure adjusting chamber 20 adheres to the inner surface 20 b of the internal pressure adjusting chamber 20. The gear lubricating grease adhering to the inner surface 20b of the internal pressure adjusting chamber 20 is heat exchanged with the outside of the internal pressure adjusting chamber 20 (specifically, the heat is released to the outside of the internal pressure adjusting chamber 20). Then, it is cured by being cooled and accumulated on the inner surface 20b of the internal pressure adjusting chamber 20 (state of grease Ga in FIG. 1B).

  In the configuration shown in FIG. 1B, as described above, since the internal pressure adjusting chamber 20 has a bellows structure, the peripheral surface of the inner surface 20b, that is, the surface area of the inner peripheral portion 20y of the internal pressure adjusting chamber 20 is shown. For example, as compared with the case of a straight structure in which the inner peripheral portion has a flat shape, it is remarkably expanded. As a result, the adhesion area of the gear lubrication grease to the inner peripheral portion 20y of the inner pressure adjusting chamber 20 can be enlarged, and the gear lubricant grease adhering to the inner peripheral portion 20y is between the outside of the inner pressure adjusting chamber 20 and the outside. Heat exchange is promoted and its cooling rate is increased. Therefore, the gear lubricating grease can be hardened at an early stage, and can be fixedly accumulated in the internal pressure adjusting chamber 20 (the inner surface 20b and the inner peripheral portion 20y).

Thus, since the gear lubricating grease that has flowed into the internal pressure adjusting chamber 20 is hardened and fixed early, it is not drawn into the communication hole 20h of the internal pressure adjusting chamber 20; The so-called plug does not block the communication hole 20h.
In addition, it is possible to effectively prevent the gear lubricating grease that has flowed into the internal pressure adjusting chamber 20 from passing through the communication hole 20h and curing inside the communication hole 20h to become a plug.

For this reason, for example, even if the internal pressure of the rotary blade unit U1 (space portion S) decreases and a pressure difference is generated between the internal pressure and the internal pressure of the internal pressure adjustment chamber 20, the internal air of the internal pressure adjustment chamber 20 Only can flow out into the rotary blade unit U1 through the communication hole 20h. As a result, the internal pressure adjustment chamber 20 can be shortened in the direction of reducing the height of the internal pressure adjustment chamber (the upward direction in FIGS. 1A and 1B) to reduce the volume. Therefore, it is possible to suppress the internal pressure of the rotary blade unit U1 from continuing to decrease, and to keep the internal pressure at a substantially constant pressure (for example, to adjust it to substantially the same pressure as the atmospheric pressure).
Thereby, since the internal pressure of the rotary blade unit U1 is always kept at substantially the same pressure, the gear lubrication grease is not continuously pressed against the rotary blade bearing 2, and the leakage of the gear lubrication grease into the rotary blade bearing 2 ( (Intrusion) can be effectively prevented.

  The internal pressure adjusting chamber 20 is configured to open only to the rotary blade unit U1 (that is, to be sealed with respect to other than the rotary blade unit U1), and therefore flows into the internal pressure adjusting chamber 20. The gear lubrication grease thus made does not leak to the outside thereof, that is, the outside of the rotary blade unit U1.

  As described above, according to the rotary blade unit U1 according to the present embodiment, the grease (gear lubrication grease and bearing lubrication grease) sealed in the interior (space S) leaks into the rotary blade bearing 2 (intrusion). In addition, leakage to the outside of the rotary blade unit U1 can be prevented. Thereby, the lubrication state of the rotary blade unit U1 is maintained well, and the cutting blade 32, which is a rotary member, can be stably rotated with a constant rotational accuracy over a long period of time.

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 the test, two mowers (corresponding to the mower A shown in FIG. 5A) are prepared as test machines, and one of the mowers has a rotary blade unit (FIG. The rotary blade unit U1) shown in a) was mounted (hereinafter, the mower is referred to as the present machine). On the other hand, a conventional rotary blade unit (rotary blade unit U2 shown in FIG. 5B) in which the internal pressure adjusting chamber 20 is not provided is mounted on the other mower (hereinafter, the mower is referred to as a comparison machine). Called).

  FIG. 4 (a) shows a test device for verifying the grease leakage prevention effect of the rotary blade unit of the mower. Using the test device, the machine and the comparator are set under predetermined conditions. The grease of the rotary blade unit of the both mowers is compared by comparing the leakage state of the grease enclosed in the rotary blade unit to the outside after operating at a predetermined speed (rotational speed of the cutting blade) for a predetermined time. The leakage prevention effect was verified.

  In addition, as shown to Fig.4 (a), the test apparatus comprised the rectangular parallelepiped box shape, and the angle steel was used as the frame material, and each surface part enclosed with the said frame material is an expanded metal, respectively. It is configured. Then, the test apparatus is fastened and fixed to the gantry with bolts, and the mower operating tube 30 and the operation handle 36 (see FIG. 5A) so that the mower is suspended in the test apparatus. Was fixed to the frame material of the test apparatus with a string.

During the test, a predetermined lubricant (gear lubrication grease (Duplex EP manufactured by Kyodo Yushi Co., Ltd.) is placed inside the rotary blade unit (the space S shown in FIGS. 1A and 5B).
No. About 13 g of 2)) was charged. This filling amount (about 13 g) corresponds to a volume amount of about 100% with respect to the space volume inside the rotary blade unit (space portion S).

  Further, as a rolling bearing that supports the main shaft of the rotary blade unit (the rotary blade side bearing 2 shown in FIGS. 1A and 5B), the outer diameter of the bearing is 32 mm, the inner diameter of the bearing is 12 mm, and the bearing width is 10 mm. A ball bearing with a contact type rubber seal attached and sealed 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. In addition, about 0.4 g of a thickener (lithium soap and base oil mineral oil (Shell Albany Grease S2 manufactured by Showa Shell Sekiyu KK)) as a lubricant (bearing lubrication grease) is sealed inside the bearing. .

  In the test, the atmospheric temperature of the mower (the present machine and the comparison machine) under test is kept at room temperature, and in this state, the present machine and the comparison machine are respectively set at a speed of 8000 revolutions per minute. It was operated continuously for hours. After that, remove the rotary blade unit from the machine and comparator, collect the grease leaked from the inside of the rolling bearing (rotary blade side bearing) with a spatula (small spoon), and check the leakage amount for the machine and comparator. Each was measured and compared. In this test, the operation of the mower (the machine and the comparator) and the measurement of the amount of grease leakage were set as one test cycle, and the test cycle was repeated three times, and the results were compared.

  FIG. 4B shows the results of each test. As is apparent from FIG. 4B, in the case of the comparator without the internal pressure adjusting chamber 20, the grease from the rolling bearing (rotating blade side bearing). The amount of leakage was 3.6 to 6.2 g, and a larger amount of grease leaked than the amount enclosed in the bearing (about 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 not only reached the cutting blade but also dropped to the floor of the test apparatus.

  On the other hand, in the case of the present machine provided with the internal pressure adjusting chamber 20, the amount of grease leakage from the rolling bearing (rotary blade side bearing) is 0.02 to 0.04 g, and the amount enclosed in the bearing (about approx. 0.4 g) was only 5 to 10%, and only 0.3 to 1.0% of the grease leakage amount of the comparative machine. In this case, the leakage of the grease was stopped to the extent that the appearance of the rotary blade unit could not be visually confirmed, and the leaked grease was only slightly adhered to the surface of the rubber seal of the bearing. .

  As described above, by providing the internal pressure adjusting chamber 20 as in the rotary blade unit U1 according to the present embodiment, grease (gear lubrication grease and bearing lubrication grease) enclosed in the interior (space portion S) of the rotary blade unit U1. It was verified by the above-described test that leakage to the outside can be surely prevented and the cutting blade 32, which is a rotating member, can be stably rotated with a constant rotational accuracy over a long period of time.

  The internal pressure adjusting mechanism provided in the rotating member support unit is not limited to the internal pressure adjusting chamber 20 (FIGS. 1A and 1B) according to the first embodiment of the present invention described above. Even when a hollow shaft structure and a drain bolt structure are applied as the internal pressure adjusting mechanism as in the second embodiment of the present invention shown in 2 (a) and (b), the same internal pressure adjusting effect can be obtained. Can do. Hereinafter, the configuration of the rotary blade unit U11 (rotary member support unit) according to the second embodiment of the present invention shown in FIGS. 2 (a) and 2 (b) will be described. At this time, the basic configuration of the rotary blade unit U11 is the same as that of the rotary blade unit U1 (FIG. 1 (a)) according to the first embodiment of the present invention described above. About a similar structure, the same code | symbol is attached | subjected on drawing, description is abbreviate | omitted, and description is stopped only to the characteristic component part of the rotary blade unit U11.

  In the second embodiment of the present invention, the rotary blade unit U11 that is a rotary member support unit has an internal pressure adjustment mechanism that opens the inside of the rotary blade unit U11 to the outside, and discharges the unit internal air to the outside of the unit. In addition, an internal pressure adjusting hole 22 is formed that allows the outside air of the unit to flow into the unit.

The internal pressure adjusting hole 22 includes a hole (hereinafter, referred to as a main shaft through hole) 8h penetrating along the extending direction of the main shaft 8 (vertical direction in FIG. 2A) and a fastening member (for example, a hexagon bolt). ) 50h that penetrates along the axis of 50 and communicates with the main shaft through hole 8h (hereinafter referred to as a fastening member through hole) 50h.
Thereby, the internal pressure adjusting hole 22 causes the unit internal air to flow into the main shaft through hole 8h and the fastening member through hole 50h when the internal pressure of the rotary blade unit U11 increases, and these through holes 8h and 50h (internal pressure adjusting hole 22). The internal pressure of the rotary blade unit U11 is adjusted to a substantially constant pressure by flowing it out of the rotary blade unit U11. On the other hand, when the internal pressure of the rotary blade unit U11 decreases, the internal air in the main shaft through hole 8h and the fastening member through hole 50h flows out into the rotary blade unit U11, and through these through holes 8h and 50h (internal pressure adjusting hole 22). The internal pressure of the rotary blade unit U11 is adjusted to a substantially constant pressure by allowing the outside air of the unit to flow into the unit.

  That is, the internal pressure adjusting hole 22 flows out the unit internal air through the internal pressure adjusting hole 22 (the main shaft through hole 8h and the fastening member through hole 50h) when the internal pressure of the rotary blade unit U11 fluctuates (when rising and when decreasing), or By letting the air from the unit flow in, it is possible to suppress the internal pressure from continuing to fluctuate, and to keep the internal pressure at a substantially constant pressure (for example, to adjust it to substantially the same pressure as the atmospheric pressure).

  The main shaft 8 has a fastening hole (female screw (hereinafter referred to as fastening screw)) 8j for fastening the fastening member 50 at a predetermined depth from the end portion on the cutting blade 32 side (lower end portion in FIG. 2A). The main shaft through hole 8h penetrates the main shaft 8 from one end (the upper end in the figure) to the fastening screw 8j, and the fastening member 50 is fastened to the fastening screw 8j to thereby connect the main shaft through hole 8h. The fastening member through-hole 50h is in communication (see an enlarged view in a circle in the figure).

In this case, the fastening member 50 is composed of a head portion 50a and a body portion 50b, and a predetermined spiral groove (male thread portion) is formed on the outer peripheral portion of the body portion 50b. Is formed with a predetermined spiral groove (female screw part) that is screwed into the spiral groove (male thread part) of the fastening member 50. Then, with the cutting blade 32 sandwiched between the cutting blade presser lid 18 and the cutting blade presser 10, the fastening member 50 (body portion 50b) is inserted into the fastening screw 8j, and both spiral grooves (male screw portions) are inserted. And the female thread portion) are screwed together and fastened to each other, whereby the cutting blade 32 can be rotatably attached to the main shaft 8.
The size (diameter size) and shape (overall shape and cross-sectional shape) of the internal pressure adjusting hole 22 (the main shaft through hole 8h and the fastening member through hole 50h), the drilling position and the number, and the like are the size of the main shaft 8 and the fastening member. It can be arbitrarily set according to the shape of 50.

  As an example, in FIGS. 2 (a) and 2 (b), an area from one end (the upper end in the figure) to a predetermined depth (the vertical distance in the figure) is tapered to gradually reduce the diameter. A circular hole having a constant diameter smaller than the diameter dimension of the fastening screw 8j from the tip to the communicating portion with the fastening screw 8j. The structure of the spindle through-hole 8h formed as (straight hole) is shown. The fastening member through hole 50h is formed as a circular hole (straight hole) having a constant diameter smaller than the diameter of the straight portion of the main shaft through hole 8h as an example. Each opening 50b is provided with an opening (hereinafter referred to as a head opening and a body opening). In this case, only one main shaft through hole 8h is formed so as to be concentric with the shaft center of the main shaft 8, and one fastening member through hole 50h is formed so as to be concentric with the shaft center of the fastening member 50. Only formed.

  Thereby, when the fastening member (for example, a hexagon bolt) 50 is fastened to the fastening screw 8j of the main shaft 8, the opening of the straight portion of the main shaft through hole 8h and the trunk portion opening of the fastening member through hole 50h are communicated with each other. A series of internal pressure adjusting holes 22 penetrating the main shaft 8 and the fastening member 50 can be formed. At that time, the tapered portion of the main shaft through hole 8h opens into a space portion SS surrounded by the gear side bearing 4 and the upper inner wall (hereinafter referred to as the upper wall 40t) of the case 40, and the space portion SS is the gear side bearing. 4 communicates with the space S through the inside. On the other hand, the head opening of the fastening member through hole 50h is open to the outside of the rotary blade unit U11. In the following description, the opening at both ends of the series of internal pressure adjusting holes 22, specifically the opening at the tapered portion of the main shaft through hole 8h (the upper opening in FIG. 2A) is the inner port 22i, and the fastening member through hole. The head opening of 50 h (lower opening in the figure) is referred to as an outer opening 22o.

  That is, the main shaft through hole 8 h communicates with the space portion S via the space portion SS and the inside of the gear-side bearing 4, and as a result, the internal pressure adjusting hole 22 communicates with the space portion S. Thereby, the space S can be opened to the outside of the rotary blade unit U11 through the internal pressure adjusting hole 22. The gear-side bearing 4 has a so-called open type (open type) bearing structure in which a sealing member (contact type seal, non-contact type seal or shield, etc.) for sealing the inside is not provided. Thus, the space portion S and the space portion SS can be easily communicated, and as a result, the space portion S and the internal pressure adjusting hole 22 can be easily communicated.

  Here, the configuration of the internal pressure adjusting hole 22 (the main shaft through hole 8h and the fastening member through hole 50h) is not limited to the configuration shown in FIGS. 2A and 2B, and for example, the straight portion of the main shaft through hole 8h. Further, the fastening member through-hole 50h may be formed as a tapered conical hole whose diameter is gradually reduced or a tapered conical hole whose diameter is gradually enlarged. Further, the internal pressure adjusting hole 22 (the main shaft through hole 8h and the fastening member through hole 50h) has a rectangular shape whose cross-sectional contour shape is a rectangle, a polygonal hole that forms a polygon, or a star shape that has a plurality of corners. You may form as a star-shaped hole. Furthermore, as long as the main shaft through hole 8h and the fastening member through hole 50h communicate with each other, the main shaft through hole 8h and the fastening member through hole 50h may be positioned so as to be shifted (eccentric) from the respective shaft centers of the main shaft 8 and the fastening member 50. Also good.

  In any case, the internal pressure adjusting hole 22 (the main shaft through hole 8h and the fastening member through hole 50h) may be formed by an arbitrary method depending on the material and length of the main shaft 8 and the fastening member 50. For example, the main shaft 8 and the fastening member 50 are formed by casting, cutting, or the like, and a predetermined drilling process is performed on the main shaft 8 and the fastening member 50 after the molding, so that the internal pressure adjusting hole 22 (the main shaft through hole 8h and the fastening member 50 are fastened). What is necessary is just to form the member through-hole 50h).

  Thus, by providing the internal pressure adjusting hole 22 (the main shaft through hole 8h and the fastening member through hole 50h) with respect to the rotary blade unit U11, the inside (space portion S) of the rotary blade unit U11 has the space portion SS and the relevant portion. The internal pressure of the rotary blade unit U11 (the internal pressure of the space portion S), the internal pressure of the space portion SS, and the internal pressure of the internal pressure adjustment hole 22 are both substantially constant pressure. It becomes a state maintained at (substantially the same pressure as atmospheric pressure).

From this state, for example, when the main shaft 8 rotates, the inside (space portion S) of the rotary blade unit U11 is pressurized, the internal pressure of the rotary blade unit U11 increases, and the internal pressure of the space portion SS and the internal pressure adjusting hole 22 is increased. When a pressure difference occurs between the two, the unit internal air (the internal air of the space S) is pressed and flows into the space SS through the inside of the gear-side bearing 4. At that time, the inside air in the space portion SS is pressed by the unit inside air flowing into the space portion SS, and flows into the internal pressure adjusting hole 22 (the main shaft through hole 8h and the fastening member through hole 50h) from the inner port 22i.
Then, the internal air in the internal pressure adjusting hole 22 (the main shaft through hole 8h and the fastening member through hole 50h) is pressed by the internal air in the space portion SS flowing into the internal pressure adjusting hole 22, and the outside of the internal pressure adjusting hole 22 from the external port 22o, that is, It is discharged to the outside of the rotary blade unit U11.

  As a result, the unit internal air that has flowed into the internal pressure adjustment hole 22 from the space S can be discharged to the outside of the internal pressure adjustment hole 22, that is, outside the rotary blade unit U11, by an amount corresponding to the inflow amount. As a result, the increase in the internal pressure of the rotary blade unit U11 is offset by discharging the unit internal air to the outside of the rotary blade unit U11, and it is possible to suppress the internal pressure of the rotary blade unit U11 from continuing to increase, and the internal pressure Can be kept at a substantially constant pressure (specifically, the pressure can be adjusted to substantially the same pressure as the atmospheric pressure).

On the other hand, from the state in which the internal pressure of the rotary blade unit U11 and the internal pressure of the internal pressure adjustment hole 22 are maintained at a substantially constant pressure, for example, when the main shaft 8 stops, the inside (space portion S) of the rotary blade unit U11 is reduced. When the internal pressure of the rotary blade unit U11 decreases and a pressure difference is generated between the space SS and the internal pressure of the internal pressure adjusting hole 22, the internal air in the space SS is sucked through the inside of the gear-side bearing 4. , Is discharged to the space S. At that time, the inside air flows into the space portion SS from the internal pressure adjusting hole 22 (the main shaft through hole 8h and the fastening member through hole 50h) through the inner port 22i by an amount corresponding to the inside air flowing out into the space portion S.
As a result, the internal pressure adjusting hole 22 (the main shaft through hole 8h and the fastening member through hole 50h) is provided outside the internal pressure adjusting hole 22 through the outer port 22o, that is, the rotary blade unit, by an amount corresponding to the internal air flowing into the space portion SS. Outside air flows in from the outside of U11.

  As a result, the internal pressure of the internal pressure adjustment hole 22 that has flowed out from the internal pressure adjustment hole 22 into the space S is an internal pressure from the outside of the internal pressure adjustment hole 22, that is, from the outside of the rotary blade unit U 11 by the amount corresponding to the outflow amount. It is possible to flow into the adjustment hole 22. Thereby, the internal pressure fall of rotary blade unit U11 is offset by flowing external air into the internal pressure adjustment hole 22 from the outside of rotary blade unit U11, and it can suppress that the internal pressure of rotary blade unit U11 continues falling. At the same time, the internal pressure can always be maintained at a substantially constant pressure (specifically, adjusted to substantially the same pressure as the atmospheric pressure).

  In addition, when the inside of the rotary blade unit U11 shifts from the pressurized state to the reduced pressure state, and also when the inside of the rotary blade unit U11 shifts from the reduced pressure state to the pressurized state, the above-described internal pressure adjusting hole 22 (the main shaft through hole 8h and the fastening member through hole). 50h), the internal pressure of the rotary blade unit U11 is always maintained at a substantially constant pressure (specifically, adjusted to substantially the same pressure as the atmospheric pressure). )be able to.

  Thus, according to the present embodiment, the internal pressure of the rotary blade unit U11 is always substantially constant by providing the internal pressure adjusting hole 22 (the main shaft through hole 8h and the fastening member through hole 50h) with respect to the rotary blade unit U11. Since it can be adjusted to a pressure (substantially the same pressure as the atmospheric pressure), there is no need to separately provide an internal pressure adjusting chamber 20 outside the case 40 as in the first embodiment of the present invention described above. Therefore, the rotary blade unit U11 has the same structure as that of the conventional rotary blade unit U2 (FIG. 5B) in appearance, and can be simplified in structure without the projection (internal pressure adjusting chamber 20), It is easy to downsize.

  In the rotary blade unit U11 having the above-described configuration, the space portion S is filled (enclosed) with gear lubricating grease of the same type and the same component configuration as the rotary blade unit U1 according to the first embodiment described above. At the same time, the bearing lubrication grease of the same type and composition as the rotary blade unit U1 is filled (enclosed) in the rolling bearings (rotary blade side bearing 2, gear side bearing 4 and drive shaft bearing 6). Lubricating at.

  Note that the volume (volume) of the internal pressure adjusting hole 22 is limited by the size of the main shaft 8 and the fastening member 50, and the volume (as an example) of the internal pressure adjusting chamber 20 (FIGS. 1A and 1B) described above. It is difficult to secure the degree of freedom as in the case of setting about 20 cc) in a normal state where the image is not enlarged or reduced. For this reason, the volume (volume) of the internal pressure adjusting hole 22 is smaller than that of the internal pressure adjusting chamber 20, and in order to enhance the internal pressure adjusting effect of the rotary blade unit U11 described above, the filling amount of the gear lubrication grease is set to the rotary blade unit U1. It is preferable to set the amount of air (unit air) in the space S to be large in advance, so that the volume of air (unit air) is large.

  Therefore, the filling amount of the gear lubrication grease in the rotary blade unit U11 is considered to suppress the softening and partial liquefaction phenomenon of the gear lubrication grease as much as possible, and the state is semi-solid (so-called grease). In order to ensure the fluidity of the air in the internal pressure adjusting hole 22 (unit internal air and unit external air), it is set to be approximately 90% or less with respect to the space volume of the space S. That's fine. At that time, the space volume of the space portion S does not include the space volume of the internal pressure adjustment hole 22, and the volume amount is approximately 90% with respect to the space volume of the space portion S excluding the space volume of the internal pressure adjustment hole 22. Thus, the filling amount of the gear lubrication grease may be set.

  As in the case of the rotary blade unit U1 according to the first embodiment of the present invention described above, the gear lubrication grease is rotated by its own weight, and the drive shaft 38 and the drive shaft gear G1 rotate, and the main shaft 8 and the main shaft gear G2. Is continuously stirred and sheared in the space S by vibration caused by rotation of the. 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 U11 (space part S) rises, so that the rotary blade unit U11 is free from the internal air of the rotary blade unit U11 and the gear lubrication grease sealed in the space part S. The pressing force in the external direction, specifically, the pressing force on the inner wall 40 s of the case 40, the main shaft 8, the rotary blade side bearing 2 and the gear side bearing 4 acts, and the gear lubricating grease is applied to the rotary blade side bearing 2. The rubber seal (not shown) falls and contacts the outer surface (surface on the drive shaft gear G1 and main shaft gear side).
In this state, the rubber seal is stationary, but on the other hand, since the main shaft 8 is rotating, the centrifugal force generated by the rotation of the main shaft 8 acts on the gear lubricating grease contacting the outer surface of the rubber seal. .

  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 outer surface of the rubber seal due to its own weight and vibration caused by the rotation. As a result, the gear lubricating grease is circulated in the space S.

  As a result, the flow of gear lubrication grease is activated in the space S, and the drive shaft gear G1 and the main shaft gear G2 do not become insufficiently lubricated, and the teeth of the gears G1, G2 are rubbed against each other and worn. Therefore, the gears G1 and 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, the gear lubrication grease that has been moved to the upper part of the space 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, partly with the unit internal air. It flows into the space portion SS through the inside of the gear side bearing 4 (see the arrow in FIG. 2B). That is, in the flow of the gear lubrication grease in the space S, the circulation flow that circulates in contact with the outer surface of the rubber seal is the main flow, while the gear lubrication grease in the space S is At the same time, it flows through the inside of the gear-side bearing 4 to the space SS. In addition, by making the gear side bearing 4 into an open type (open type) bearing structure as described above, the gear lubrication grease can easily flow from the space portion S to the space portion SS.

The gear lubricating grease that has flowed into the space SS is less likely to soften or liquefy because stirring and shearing are reduced, and can be collected in the space SS in a semi-solid state (so-called grease). (State of grease Gs shown in FIG. 2B). Then, the semi-solid (so-called grease-like) gear lubricating grease collected in the space SS adheres to the upper wall 40t of the case 40 and is heat-exchanged with the outside of the case 40 (specifically It releases its heat to the outside) and is cured by being cooled. For this reason, in the space portion SS, the gear lubrication grease does not hinder the flow of the unit internal air flowing into the space portion SS, and the fluidity thereof can be sufficiently ensured.
When the gear lubrication grease flows excessively into the space SS, the grease flows from the inner port 22i to the inner pressure adjusting hole 22 (specifically, the main shaft through hole 8h) (see the circle in FIG. 2B). It can be collected by the internal pressure adjusting hole 22 (the main shaft through hole 8h and the fastening member through hole 50h) (state of grease Gt shown in the same figure).

  Here, in the main shaft 8 and the gear side bearing 4, the upper end surface (end surface on the inner hole 22i side) of the main shaft 8 is more convex than the upper end surface of the gear side bearing 4 (end surface on the upper wall 40t side of the case 40). It is preferable to relatively position the two so as to obtain the configuration described above. That is, as shown in FIG. 2 (b), the height difference between the upper end surface of the gear side bearing 4 and the upper end surface of the main shaft 8 with respect to the extending direction of the main shaft 8 (vertical direction in FIG. The main shaft 8 and the gear-side bearing 4 may be positioned so that the indicated distance b1) is at least a positive value (b1> 0). As a result, the centrifugal force generated by the rotation of the main shaft 8 can be applied to the gear lubrication grease that flows into the space portion SS through the inside of the gear side bearing 4 together with the inside air of the unit, and is collected in the space portion SS. it can.

  That is, by applying the centrifugal force, the gear lubricating grease collected in the space portion SS is prevented from flowing in the direction of the main shaft 8, and the gear lubricating grease is flowed in the direction of the gear side bearing 4, It can be pushed back into it. Since the gear lubrication grease pushed back into the gear side bearing 4 flows into the space S due to its own weight, the grease can contribute again to the lubrication of the drive shaft gear G1 and the main shaft gear G2.

  Even when the gear lubrication grease collected in the space SS reaches the vicinity of the inner hole 22i of the main shaft 8, the vicinity of the inner hole 22i becomes tapered toward the inside of the main shaft through hole 8h. Due to the conical shape (FIG. 2B), the grease is easily pushed out from the vicinity of the inner hole 22i to the space SS along the conical surface by the action of the centrifugal force caused by the rotation of the main shaft 8. (See the arrow in the circle in FIG. 2 (b)). As a result, the gear lubricating grease can flow in the direction of the gear side bearing 4 and can be pushed back into the gear side bearing 4.

  In addition, the size of the space portion SS can collect the gear lubrication grease that has flowed, and if the fluidity of the air flowing into the unit can be sufficiently secured, What is necessary is just to set arbitrarily according to a magnitude | size. For example, the main shaft 8 is positioned in the case 40 so that the distance between the upper end surface of the main shaft 8 and the upper wall 40t of the case 40 (distance b2 shown in FIG. 2B) is set to about 2 mm. That's fine.

  Thus, the gear lubrication grease actively flows in the space S and repeats circulation (the main flow described above) when the mower is in use, that is, when the rotary blade unit U11 is in operation. For this reason, the gear lubrication grease hardly accumulates (deposits) on the rubber seal outer surface (surface on the side of the drive shaft gear G1 and the main shaft gear G2) of the rotary blade side bearing 2 described above. As a result, it is possible to reliably prevent the gear lubricating grease from leaking (invading) into the rotary blade side bearing 2.

  In the present embodiment, by providing the internal pressure adjusting hole 22 (the main shaft through hole 8h and the fastening member through hole 50h), the internal pressure of the rotary blade unit U11 is prevented from continuously fluctuating, and the internal pressure is always substantially constant. Since it can be maintained at a pressure (for example, adjusted to substantially the same pressure as the atmospheric pressure), the gear lubrication grease that contacts the outer surface of the rubber seal of the rotary blade side bearing 2 is in contact with the lip portion of the seal and the rotary blade side. There is no pressing force enough to slip through the sliding contact portion of the bearing 2 with the seal groove. Thereby, it is possible to reliably prevent the gear lubricating grease from leaking (intruding) into the rotary blade side bearing 2.

  As described above, according to the rotary blade unit U11 according to this embodiment, the grease (gear lubrication grease and bearing lubrication grease) sealed in the interior (space S) leaks into the rotary blade bearing 2 (intrusion). In addition, leakage to the outside of the rotary blade unit U11 can be prevented. Thereby, the lubrication state of the rotary blade unit U11 is maintained well, and the cutting blade 32, which is a rotary member, can be stably rotated with a constant rotational accuracy over a long period of time.

  Note that the internal pressure adjusting hole as the internal pressure adjusting mechanism provided in the rotating member support unit has the configuration according to the above-described second embodiment of the present invention (the main shaft through hole 8h and the fastening member through hole 50h) (FIGS. 2A and 2B). For example, as in the third embodiment of the present invention shown in FIGS. 3 (a) and 3 (b), the internal pressure adjusting hole 22 is formed in the main shaft through hole 8h and the fastening member through hole 50h. In addition, the main shaft branch hole 8t may be formed (perforated). Hereinafter, the configuration of the rotary blade unit U12 (rotary member support unit) according to the third embodiment of the present invention shown in FIGS. 3 (a) and 3 (b) will be described. At that time, the basic configuration of the rotary blade unit U12 is the same as that of the rotary blade unit U11 (FIGS. 2A and 2B) according to the second embodiment of the present invention described above. About the structure which is the same as or similar to U11, the same code | symbol is attached | subjected on drawing, description is abbreviate | omitted, and description is stopped only to the characteristic structure part (spindle branch hole 8t) of rotary blade unit U12.

  In the rotary blade unit U12 according to the third embodiment of the present invention, as the internal pressure adjusting hole 22, in addition to the main shaft through hole 8h and the fastening member through hole 50h, the main blade is branched from the main shaft through hole 8h and along the radial direction. A branch hole (hereinafter, referred to as a main shaft branch hole) 8 t that extends radially and opens on the outer peripheral surface of the main shaft 8 is formed with respect to the main shaft 8.

  In this case, as shown in FIGS. 3A and 3B, the main shaft branch hole 8t extends from the main shaft through hole 8h so that the opening 8i on the outer peripheral surface of the main shaft 8 is positioned in the vicinity of the drive shaft gear G1. It is preferable to branch and extend at least one radially along the radial direction of the main shaft 8. Thereby, the spindle branch hole 8t can communicate the spindle through hole 8h with the space S of the rotary blade unit U12. That is, the main shaft through hole 8h communicates with the space portion S via the space portion SS and the inside of the gear side bearing 4, and also communicates with the space portion S via the main shaft branch hole 8t.

  The size (diameter size) and shape (overall shape and cross-sectional shape) of the main shaft branch hole 8t, the drilling position and the number, and the like can be arbitrarily set according to the size of the main shaft 8 and the like. For example, with respect to the main shaft 8 (main shaft through hole 8h), a plurality of main shaft branch holes 8t are radiated along the radial direction at the same height position in the axial direction (vertical direction in FIGS. 3A and 3B). A perforated configuration may be used. Further, the main shaft 8 (main shaft through hole 8h) may be configured such that a plurality of main shaft branch holes 8t are formed by shifting the height position in the axial direction. At that time, the phase in the circumferential direction of each spindle branch hole 8t may be the same or different.

  In the rotary blade unit U12 having such a configuration, gear lubrication grease having the same type and the same component configuration as the rotary blade units U1 and U11 according to the first and second embodiments described above is used as the space S. The bearing lubrication grease of the same type and composition as the rotary blade units U1 and U11 is filled (enclosed) with rolling bearings (rotary blade side bearing 2, gear side bearing 4 and drive shaft bearing 6). Lubrication is performed by filling (sealing) the inside.

  The gear lubrication grease is circulated in the space S and the centrifugal force generated with the rotation of the main shaft 8 as in the case of the rotary blade units U1 and U11 according to the first and second embodiments described above. As a result of the above, 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 move along the space S, respectively, and a part of them passes through the inside of the gear side bearing 4 together with the unit air. And flow into the space SS (see the arrow in FIG. 3B). That is, the flow of the gear lubrication grease in the space portion S is the main flow of the circulating flow in the space portion S, while the gear lubrication grease in the space portion S together with the unit internal air as a side flow. Will flow into the space SS through the interior of the. In addition, by making the gear side bearing 4 into an open type (open type) bearing structure as described above, the gear lubrication grease can easily flow from the space portion S to the space portion SS.

  The gear lubricating grease that has flowed into the space SS is less likely to soften or liquefy because stirring and shearing are reduced, and can be collected in the space SS in a semi-solid state (so-called grease). (State of grease Gs shown in FIG. 3B). Then, the semi-solid (so-called grease-like) gear lubricating grease collected in the space SS adheres to the upper wall 40t of the case 40 and is heat-exchanged with the outside of the case 40 (specifically It releases its heat to the outside) and is cured by being cooled. For this reason, in the space portion SS, the gear lubrication grease does not hinder the flow of the unit internal air flowing into the space portion SS, and the fluidity thereof can be sufficiently ensured.

If the gear lubrication grease flows excessively into the space SS, the grease flows from the inner port 22i to the inner pressure adjusting hole 22 (specifically, the main shaft through hole 8h) (see the circle in FIG. 3B). It can be collected by the internal pressure adjusting hole 22 (the main shaft through hole 8h and the fastening member through hole 50h) (state of grease Gt shown in the same figure).
Further, when gear lubrication grease continuously flows to the space SS, the gear lubrication grease collected by the internal pressure adjusting hole 22 (the main shaft through hole 8h and the fastening member through hole 50h) is caused by centrifugal force. It is pushed out from the spindle through hole 8h to the spindle branch hole 8t. Thereby, the gear lubricating grease can be collected also by the main shaft branch hole 8t.

  Further, the gear lubricating grease pushed out from the main shaft through hole 8h to the main shaft branch hole 8t causes the main shaft branch hole 8t to extend in the extending direction (radial direction (rightward in FIG. 3B) by the action of the centrifugal force. Then, the gear lubricating grease that has flowed through the main shaft branch hole 8t is discharged from the opening 8i to the space portion S and mixed with the gear lubricating grease in the space portion S. Thereafter, the space that is the main flow. The circulation in the part S and the flow to the space part SS which is a secondary flow are repeated again.

  Thereby, the flow of the gear lubrication grease is further activated in the space S, and the grease can contribute to lubrication of the drive wheel gear G1 and the main shaft gear G2 more effectively. As a result, the drive shaft gear G1 and the main shaft gear G2 are not insufficiently lubricated, and the teeth of the gears G1 and G2 are also prevented from being frictioned and worn. Can be rotated smoothly. Further, since heat generation of the drive wheel gear G1 and the main shaft gear G2 can be suppressed and deterioration of the gear lubrication grease can be prevented, as a result, the grease can be used for lubricating the drive shaft gear G1 and the main shaft gear G2 for a longer period of time. Can contribute.

  In addition, as described above, according to the present embodiment, the gear lubricating grease collected by the internal pressure adjusting hole 22 (the main shaft through hole 8h and the fastening member through hole 50h) is separated into the space portion via the main shaft branch hole 8t. Return to S. For this reason, the gear lubricating grease collected by the internal pressure adjusting hole 22 (the main shaft through hole 8h and the fastening member through hole 50h) can be effectively prevented from entering the fastening member through hole 50h from the main shaft through hole 8h. Thus, it is possible to reliably avoid a situation where the fastening member through hole 50h is leaked from the outer port 22o to the outside of the internal pressure adjusting hole 22, that is, the outside of the rotary blade unit U12.

  Other effects of the rotary blade unit U12 according to the present embodiment, such as a structural effect that enables downsizing, an effect of preventing leakage of grease (gear lubrication grease and bearing lubrication grease), and an effect of adjusting internal pressure, etc. Since this is the same as the rotary blade unit U11 according to the second embodiment described above, description thereof is omitted.

It is a figure which shows the structure of the rotary blade unit which concerns on 1st Embodiment of this invention, Comprising: (a) is sectional drawing of the state which fixed the internal pressure adjustment chamber, (b) shows the structural example of an internal pressure adjustment chamber. Sectional drawing. It is a figure which shows the structure of the rotary blade unit which concerns on 2nd Embodiment of this invention, Comprising: (a) is sectional drawing, (b) is a structural example of an internal pressure adjustment hole (a spindle through-hole and a fastening member through-hole). The principal part expanded sectional view which shows. It is a figure which shows the structure of the rotary blade unit which concerns on 3rd Embodiment of this invention, Comprising: (a) is sectional drawing, (b) is an internal pressure adjustment hole (a spindle through hole, a fastening member through hole, and a spindle branch hole). The principal part expanded sectional view which shows the structural example of). 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 mower, Comprising: (a) is a perspective view which shows the whole structure, (b) is sectional drawing of a rotary blade unit.

Explanation of symbols

2 Rotary blade side bearing 4 Gear side bearing 8 Main shaft 20 Internal pressure adjusting chamber 20b Internal pressure adjusting chamber inner surface 20u Internal pressure adjusting chamber minimum diameter portion 20v Internal pressure adjusting chamber maximum diameter portion 20y Internal pressure adjusting chamber peripheral surface 32 Cutting blade 34 Engine 38 Drive shaft Ga Grease G1 Drive shaft gear G2 Main shaft gear U1 Rotary blade unit

Claims (7)

A main shaft extending in a predetermined direction, a plurality of rolling bearings rotatably supporting the main shaft, and a driving shaft for transmitting the rotational force of the driving shaft rotated by the driving device to the main shaft; Provided with an internal pressure adjusting mechanism for always maintaining an internal pressure at a substantially constant pressure, comprising at least one set of gears provided on one end side of the main shaft and meshing with each other, and a rotating member attached to the other end side of the main shaft A rotating member support unit,
As an internal pressure adjusting mechanism, an internal pressure adjusting chamber is provided that is open only to the rotating member support unit and that can collect and accumulate the lubricant sealed in the unit. The volume of the rotating member support unit is configured so as to be freely expandable and contractible, and at least one communication hole communicating with the inside of the rotating member support unit is provided. When the internal pressure of the rotating member support unit increases, When the internal pressure is decreased, the internal pressure of the internal pressure adjusting chamber flows out from the communication hole to the unit to reduce the volume, so that the internal pressure of the unit is always substantially constant. A rotating member support unit that is adjusted to a pressure.   The internal pressure adjusting chamber has an elastic structure that can be expanded and contracted in a predetermined direction, and when the internal pressure of the rotating member support unit is increased, the internal pressure adjusting chamber expands in the predetermined direction, thereby expanding its volume. The rotating member support unit according to claim 1, wherein when the internal pressure of the unit is reduced, the volume is reduced by shortening in the predetermined direction. A main shaft extending in a predetermined direction, a plurality of rolling bearings rotatably supporting the main shaft, and a driving shaft for transmitting the rotational force of the driving shaft rotated by the driving device to the main shaft; An internal pressure adjustment for keeping the internal pressure at a substantially constant pressure by providing at least one set of gears provided on one end side of the main shaft and meshing with each other and a rotating member attached to the other end side of the main shaft by a fastening member A rotating member support unit provided with a mechanism,
As an internal pressure adjusting mechanism, the inside of the rotating member support unit is opened to the outside, allowing the inside air of the unit to flow out of the unit and allowing the outside air of the unit to flow into the unit. An internal pressure adjusting hole is formed, and the internal pressure adjusting hole passes through the main shaft through hole extending along the extending direction of the main shaft and the axis of the fastening member, and passes through the main shaft. When the internal pressure of the rotating member support unit rises, the inside air of the unit flows into the main shaft through hole and the fastening member through hole, and the unit passes through these through holes. While the internal pressure of the main shaft through-hole and the fastening member through-hole flows out into the unit when the internal pressure is reduced. Outside air of the unit through the through-holes by causing to flow into the interior of the unit, the rotating member supporting unit, characterized in that it is constantly adjusted to substantially constant pressure to the internal pressure of the unit.   A fastening hole for fastening the fastening member is formed in the main shaft at a predetermined depth from the other end, and the main shaft through hole penetrates the main shaft from the one end to the fastening hole. The main shaft through hole and the fastening member through hole are communicated with each other by fastening the fastening member in a hole, and the inside of the rotating member support unit is open to the outside. The rotating member support unit described.   In addition to the main shaft through hole and the fastening member through hole, the main shaft has a main shaft branch hole that branches off from the main shaft through hole and extends radially along the radial direction and opens on the outer peripheral surface of the main shaft. The rotation member support unit according to claim 3 or 4, wherein the rotation member support unit is formed as an adjustment hole.   The main shaft branch hole branches from the main shaft through hole so that the opening on the outer peripheral surface of the main shaft is positioned in the vicinity of the gear provided on the drive shaft, and at least one of the main shaft branch holes is radially along the radial direction of the main shaft. The rotating member supporting unit according to claim 5, wherein the rotating member supporting unit is extended.   The rotating member support unit according to any one of claims 1 to 6, 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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