JP2008022772A - Rotation member-supporting unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotation member-supporting unit that prevents the grease sealed inside from leaking out by always keeping the inner pressure to almost same as the atmospheric one, and further can continuously rotate the rotation member stably with a constant degree of rotation accuracy for a long period of time. <P>SOLUTION: The rotation member-supporting unit U1 is equipped with the main shaft 8 that is set vertically as extending in a prescribed direction; a plurality of rolling bearings 2, 4 that rotation-freely supporting the main shaft; at least one set of gears G1, G2 are arranged on one edge side of the driving shaft and on one edge side of the main shaft as they engage each other to transmit the rotation power of the driving shaft 38 rotated by the driving apparatus 34 to the main shaft; and the rotation member 32 that is attached on the other edge side of the main shaft. This unit is equipped with an inner pressure regulator 20 that has at least one of air hole 20a for keeping the inner pressure at the same of the atmospheric one, when the inner pressure rises, the inner air is discharged from the inside to the outside, or when the inner pressure lowers, the outside air is introduced in from the outside of the unit. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to, for example, a grass cutter, a brush cutter and a lawn mower, or a power tool used for cutting off grass (e.g., weeds) growing on the ground surface from the vicinity of the root, and in particular, a cutting blade attached thereto. The present invention relates to an improvement of a rotating member support unit that supports a rotating member such as a (rotating blade).

FIGS. 3A and 3B 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 extending linearly, a rotary blade unit (rotary member support unit) U2 provided on one end side of the operation tube 30, and the operation. A driving device (engine) 34 provided on the other end side of the 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 (drive shaft bearing). 6 is rotatably supported. A gear (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 so as to drive the drive shaft 38. The 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 (under the rotary blade side bearing 2 (FIG. 3B) that rotatably support the main shaft 8. Side bearing) and gear side bearing 4 (upper bearing in the figure)) and one end side of the drive shaft 38 and the main shaft 8 (FIG. 3B) in order to transmit the rotational force of the drive shaft 38 to the main shaft 8. ) On the left end side and the upper end side), and a pair of gears (drive shaft gear G1 (right gear in FIG. 3B) and main shaft gear G2 (left gear in FIG. 3)). And a rotatable cutting blade (rotating member) 32 attached to the other end side of the main shaft 8 (lower end side in FIG. 3B).

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. 3B). Further, the operation tube 30 is provided with a protective cover 40 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 formed in the inner ring of the rotary blade side bearing 2. It is positioned so as to be in sliding contact with (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.

If the rubber seal (not shown) is continuously pressed by the gear lubrication grease, as a result, 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 to the rotary blade side. 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 or malfunction of the grease.
JP 2004-194521 A JP-A-8-130959

  However, when leakage (penetration) of the gear lubrication grease into the bearing progresses as described above, the amount of grease in the rotary blade side bearing 2 increases from a set value, and stirring and shearing are activated, 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, the leaked grease adheres to the cutting blade 32 (the state of the grease G in FIG. 3B), which may deteriorate the rotational accuracy of the cutting blade 32, as well as against vegetation and soil. There is also a risk of adverse effects.

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

  As a measure for avoiding such inconvenience, for example, as a gear lubrication grease, the NLGI consistency is No. 3 or No. No. 4 grease, that is, NLGI consistency No. Applying a grease harder than the grease No. 2 to suppress the softening caused by stirring or shearing the grease, the grease is attached 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 worn due to friction with each other. 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, and its purpose is to keep the internal pressure at substantially the same pressure as the atmospheric pressure, thereby preventing leakage of grease enclosed inside to the outside, It is an object of the present invention to provide a rotating member support unit capable of continuously rotating the rotating member with a constant rotation 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 a member. When the internal pressure of the rotating member support unit increases, the internal air is discharged from the inside of the unit to the outside, and when the internal pressure decreases, the external air is transferred from the outside to the inside of the unit. An internal pressure adjusting mechanism having at least one air hole for keeping the internal pressure of the unit at substantially the same pressure as the atmospheric pressure by being introduced is provided.

The rotating member support unit is provided with an internal pressure adjusting chamber that can communicate with the outside of the rotating member support unit only by an air hole as an internal pressure adjusting mechanism. In addition, at least one communication hole communicating with the unit is formed, and a lubricant reservoir for collecting and storing the lubricant sealed in the unit is provided. In this case, the lubricant reservoir is positioned closer to the other end of the main shaft than the opening of the air hole and the opening of the communication hole.
The main shaft is provided with a cutting blade as a rotating member for cutting away vegetation growing on the ground surface from the vicinity of the root.

  According to the rotating member support unit of the present invention, the internal pressure can always be maintained at substantially the same pressure as the atmospheric pressure. As a result, leakage of grease enclosed inside can be prevented and the rotating member can be maintained for a long time. It is possible to continue to rotate stably with a constant rotational accuracy.

  Hereinafter, a rotating member support unit according to an embodiment of the present invention will be described with reference to the accompanying drawings. The present invention can be applied as a rotating member support unit mounted on, for example, a mower, a brush cutter and a lawn mower, or an electric tool. That is, the present invention can be applied to a rotating member support unit in which a main shaft extends in a predetermined direction and is installed to support various rotating members that rotate together with the main shaft. A configuration of the rotary blade unit will be described on the assumption that a rotary blade unit used for a mowing machine in which a cutting blade (rotary blade) for cutting off a plant from the base is attached to a main shaft as a rotary member is taken as an example. In this case, as the overall configuration of the mower according to the present embodiment, the same configuration as that of the conventional mower A (FIG. 3A) described above is assumed as an example. Further, since the basic configuration of the rotary blade unit according to the present embodiment is the same as the conventional rotary blade unit U2 (FIG. 3B) 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.

  FIGS. 1A and 1B show a rotary blade unit U1 (rotary member support unit) of a mower according to an embodiment of the present invention. The rotary blade unit U1 has a predetermined direction. The rotation of the drive shaft 38 rotated by the extended main shaft 8, a plurality of rolling bearings 2 and 4 that rotatably support the main shaft 8, and the drive device (see the engine 34 (see FIG. 3A)). In order to transmit to the main shaft 8, 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, 4 and the gears G1, G2 are respectively housed in a cylindrical case 40, and the cutting blade 32 is fastened and fixed to the main shaft 8 by a fastening member (screw). It is attached to the outside of the case 40 (the lower side of FIG. 1A).
The main shaft 8 is erected so as to extend in a substantially vertical direction when the mower is in use, whereas the drive shaft 38 has a predetermined inclination angle (with respect to the drive shaft 38). And an angle formed between the main shaft 8 and the main shaft 8 via the drive shaft gear G1 and the main shaft gear G2. The inclination angle is arbitrarily set according to, for example, the usage environment or purpose of use of the mower, and is not particularly limited here. As an example, in the present embodiment, the drive shaft 38 is the main shaft 8. Is inclined at an inclination angle of about 120 ° (about 30 ° with respect to the cutting blade 32 in another way) (FIG. 1A).

  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).

  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. Thereby, the drive shaft gear G1 and the main shaft gear G2 change the direction of the rotational force generated from the engine 34 (FIG. 3A) 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 discharges the internal air from the inside of the unit to the outside when the internal pressure increases, and allows the external air to flow from the outside to the inside of the unit when the internal pressure decreases. An internal pressure adjusting mechanism having at least one air hole for keeping the internal pressure of the rotary blade unit U1 at substantially the same pressure as the atmospheric pressure is provided. In the configuration shown in FIGS. 1A and 1B, as an internal pressure adjusting mechanism, an internal pressure adjusting chamber 20 that can communicate with the outside of the rotary blade unit U1 (upper space in FIG. 1A) only through the air hole 20a. Is provided as an example.

  As an example, the internal pressure adjusting chamber 20 is hollow inside, specifically, has a predetermined substantially cylindrical space inside, and the outer shape thereof is also substantially cylindrical, and is formed at the upper portion of the case 40 (the main shaft 8). One is provided outside in the extending direction (above the vertical direction in FIG. 1A). In this case, the internal pressure adjusting chamber 20 has only one air hole 20a, and can communicate with the outside of the rotary blade unit U1 (upper space in FIG. 1A) only through the air hole 20a. It is configured.

  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, as an example, the internal pressure adjusting chamber 20 has an inner diameter (a distance d1 in the left-right direction in FIGS. 1A and 1B) of 40 mm and an inner height (FIG. Suppose that the distance 1) in the vertical direction of 1 (a) and (b) has a substantially cylindrical internal space of 20 mm. Two or more internal pressure adjusting chambers 20 may be provided for the rotary blade unit U1.

  Further, in the configuration shown in FIGS. 1A and 1B, the internal pressure adjusting chamber 20 is formed so that the external shape and the internal shape are both substantially cylindrical as an example. It is not limited to. For example, while having a predetermined substantially conical space inside, the outer shape may be formed so as to form a substantially conical shape, or there is a predetermined rectangular space inside, and the outer shape is also rectangular. You may form so that it may comprise. 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.

  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 this case, the internal pressure adjustment chamber 20 is provided with an attachment portion 20s for attaching the internal pressure adjustment chamber 20 to the rotary blade unit U1 at a portion facing the case 40, and the attachment portion 20s has an outer diameter. It has a concentric cylindrical shape smaller than the inner diameter of the internal pressure adjusting chamber 20. Note that a part (projecting part 20d) of the mounting part 20s projects to the case 40 side, and the other part (projecting part 20e) projects to the inside (internal space) side of the internal pressure adjusting chamber 20. The internal pressure adjusting chamber 20 is positioned.

  Here, the size, shape, position, and case length of the mounting portion 20s and the length of each protrusion to the inner side of the internal pressure adjusting chamber 20 depend on the size of the rotary blade unit U1 and the internal pressure adjusting chamber 20, for example. Therefore, there is no particular limitation here. For example, in the configuration shown in FIG. 1B, the mounting portion 20s (specifically, the protruding portion 20d into the internal pressure adjusting chamber 20) so that the internal volume of the internal pressure adjusting chamber 20 is about 20 cc. Is set to a predetermined size (volume). Note that the mounting 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.

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

  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, as an example, the communication hole 20h is formed as a circular hole having a diameter (a distance d2 in the left-right direction in FIG. 1B) of 1 mm. Suppose. Further, 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, rectangular holes, or the like.

In this case, a predetermined spiral groove (for example, a male screw portion 20m) is formed on the outer peripheral surface of the protruding portion 20e 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 (predetermined space part surrounding the drive shaft gear G1 and the main shaft gear G2) S and the inside of the internal pressure adjusting chamber 20 can be communicated with each other 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 cylindrical hole 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 male screw 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 thread portion of the case 40 forms a helical groove set to an outer diameter, an inner diameter, and a pitch dimension that can be screwed with the male thread 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 attachment portion 20s of the internal pressure adjusting chamber 20 may be fitted and fixed to the circular hole 40h of the case 40. Adhesive fixation may be used.

  In the configuration shown in FIG. 1B, as an example, the internal pressure adjusting chamber 20 has an end surface 20t (upper surface in the same figure) on the side opposite to the mounting portion 20s with respect to the case 40 (upper side in the same figure). One air hole 20a reaching the inside is provided. In this case, the air hole 20a is provided at a predetermined position near the outer diameter portion of the end face 20t (the left end portion in FIG. 1B).

  Note that the size, shape, length, position, number, and the like of the air holes 20a are arbitrarily set according to, for example, the size of the internal pressure adjusting chamber 20, and are not particularly limited here. For example, in the configuration shown in FIG. 1B, the case where the air hole 20a is formed as a circular hole having a cylindrical shape with a diameter (the distance d3 in the left-right direction in FIG. 1B) is taken as an example. Suppose. Further, for example, two or more air holes 20a may be formed in the internal pressure adjusting chamber 20, and the air holes 20a may be conical holes, rectangular holes, or the like.

  The air hole 20a discharges the internal air from the inside of the rotary blade unit U1 to the outside when the internal pressure of the rotary blade unit U1 increases, and allows the external air to flow from the outside to the inside of the rotary blade unit U1 when the internal pressure decreases. Thus, the internal pressure of the rotary blade unit U1 is maintained at substantially the same pressure as the atmospheric pressure. That is, when the inside of the rotary blade unit U1 is pressurized, the air hole 20a discharges the internal air from the inside of the rotary blade unit U1 to the outside of the unit, and the internal pressure continues to increase by reducing the internal pressure. Suppressed and adjusted so that the pressure is always almost the same as the atmospheric pressure. On the other hand, when the inside of the rotary blade unit U1 is depressurized, the air holes 20a prevent the internal pressure from continuing to decrease by allowing outside air to flow into the unit from the outside of the rotary blade unit U1 and increasing its internal pressure. However, the pressure is always adjusted to be almost the same as the atmospheric pressure.

  As described above, the air hole 20a is configured as a so-called air valve that constantly adjusts the internal pressure so that a pressure difference between the inside and the outside of the rotary blade unit U1 does not occur. In this case, for example, a connecting member such as a tube is exposed to the outside of the internal pressure adjusting chamber 20 with respect to the air hole 20a, and the tip end portion of the connecting member faces downward (downward in FIGS. 1A and 1B). ) Is mounted on the rotary blade unit U1 (internal pressure adjusting chamber 20) from the outside through the air hole 20a to prevent foreign matter (for example, sludge water or dust) from entering the inside.

  Further, the internal pressure adjusting chamber 20 is provided with a lubricant reservoir 20p for collecting and storing the lubricant enclosed in the rotary blade unit U1, and the lubricant reservoir 20p It is positioned closer to the other end of the main shaft 8 (closer to the lower ends of FIGS. 1A and 1B) than the opening L3 of the hole 20a and the opening L2 of the communication hole 20h.

  In the configuration shown in FIG. 1B, the lubricant reservoir 20p is sandwiched between the protruding portion 20d of the mounting portion 20s into the internal pressure adjusting chamber 20 and the inner wall 20w of the internal pressure adjusting chamber 20 as an example. It is configured as an annular space. In addition, since the magnitude | size, shape, position, number, etc. of the lubricant storage part 20p are arbitrarily set according to the magnitude | size of the internal pressure adjustment chamber 20, the attaching part 20s, etc., for example, it does not specifically limit here.

  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 in the rotary blade unit U1 (a predetermined space surrounding the drive shaft gear G1 and the main shaft gear G2) S.
Consistency No. specified by the Lubricating Grease Institute) No. 2 (consistency number 2) grease (hereinafter referred to as gear lubrication grease) is filled (enclosed) so that the volume ratio of the space S is approximately 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 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 (predetermined space portion surrounding the drive shaft gear G1 and the main shaft gear G2) S increases, the internal pressure and the outside of the rotary blade unit U1 (space portion S) are increased. A pressure difference is generated between the pressure (external pressure (atmospheric pressure)). As a result, for example, against the inside air of the rotary blade unit U1 and the gear lubrication grease sealed in the space portion S, the pressing force toward the outside of the rotary blade unit U1, specifically, the inner wall S1 of the space portion S A pressing force is applied to the rotary blade bearing 2.

  In the present embodiment, since the internal pressure adjusting chamber 20 is provided in the rotary blade unit U1, the internal air of the rotary blade unit U1, even when such a pressing force acts on the gear lubricating grease, In addition, the gear lubricating grease sealed in the space S can be collected by flowing into the internal pressure adjusting chamber 20 through the communication hole 20h (see the arrow in FIG. 1B). Thereby, for example, gear lubricating grease can be prevented from continuing to be pressed against the rotary blade bearing 2 and leaking (invading) into the inside thereof.

Also, the inside air collected inside the internal pressure adjusting chamber 20 can be discharged from the air hole 20a of the internal pressure adjusting chamber 20 to the outside of the rotary blade unit U1 (internal pressure adjusting chamber 20). As a result, the internal pressure of the rotary blade unit U1 (space portion S) can be reduced, the internal pressure can be prevented from continuing to rise, and can be adjusted so as to always be substantially the same pressure as the atmospheric pressure. In this case, the internal pressure of the internal pressure adjusting chamber 20 is equal to the internal pressure of the rotary blade unit U1 (space portion S), and the internal pressure of the internal pressure adjusting chamber 20 is always adjusted to be substantially the same as the atmospheric pressure. be able to.
On the other hand, the gear lubricating grease collected inside the internal pressure adjusting chamber 20 can be stored in the lubricant reservoir 20p. In this case, the gear lubricating grease stored in the lubricant reservoir 20p is not agitated and sheared, and its temperature decreases and becomes semi-solid (state of the grease G in FIG. 1B). .

  In the present embodiment, as described above, the internal pressure of the rotary blade unit U1 (space portion S) is always adjusted to be substantially the same as the atmospheric pressure by the air hole 20a of the internal pressure adjusting chamber 20. Therefore, the gear lubricating grease stored in the lubricant reservoir 20p is cured by the action of the thickener as the temperature decreases, and adheres to the lubricant reservoir 20p. As a result, the gear lubrication grease stored in the lubricant reservoir 20p is not drawn into the communication hole 20h. For example, the hardened gear lubrication grease becomes a so-called plug and blocks the communication hole 20h. Absent.

  Furthermore, in the present embodiment, the lubricant reservoir 20p is closer to the other end of the main shaft 8 than the opening L3 of the air hole 20a and the opening L2 of the communication hole 20h (closer to the lower ends of FIGS. 1A and 1B). Therefore, the gear lubricating grease that has flowed into the internal pressure adjusting chamber 20 can be dropped into the lubricant reservoir 20p by its own weight and collected (Grease G in FIG. 1B). State). As a result, it is possible to effectively prevent the gear lubrication 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, the internal pressure of the rotary blade unit U1 (space portion S) is reduced, and a pressure difference is generated between the internal pressure and the external pressure (atmospheric pressure) of the rotary blade unit U1 (space portion S). However, the air hole 20a of the internal pressure adjustment chamber 20 allows outside air to flow into the internal pressure adjustment chamber 20 from the outside of the rotary blade unit U1, and only the external air passes through the communication hole 20h. Can flow into the interior. As a result, the internal pressure of the rotary blade unit U1 (space portion S) can be increased, the internal pressure can be prevented from continuing to decrease, and can be adjusted so as to always be substantially the same pressure as the atmospheric pressure. Thereby, for example, it is possible to more effectively prevent gear lubricating grease from being continuously pressed against the rotary blade bearing 2 and leaking (invading) into the inside thereof.

  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, 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 this test, two mowers (corresponding to the mower A shown in FIG. 3A) are prepared as test machines, and one of the mowers has a rotary blade unit (see 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. 3 (b)) in which the internal pressure adjusting chamber 20 is not provided is mounted on the other mower (hereinafter referred to as the comparative mower). Called).

  FIG. 2 (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 present 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.

  As shown in FIG. 2 (a), the test apparatus has a rectangular parallelepiped box shape, and angle steel is used as the frame material, and each surface portion surrounded by the frame material is an expanded metal. It is configured. Then, the test apparatus is fastened and fixed to the gantry with bolts, and the mower operating tube 30 and the operation handle 36 (see FIG. 3A) 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 No. 2 manufactured by Kyodo Yushi Co., Ltd.)) is placed inside the rotary blade unit (the space S shown in FIGS. 1A and 3B). About 13 g. 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 for supporting the main shaft of the rotary blade unit (the rotary blade side bearing 2 shown in FIGS. 1A and 3B), 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 the comparator, collect the grease leaked from the inside of the rolling bearing (rotary blade side bearing) with a spatula, measure the leakage amount for the machine and the comparator, 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. 2 (b) shows the results of each test. As is clear from FIG. 2, in the case of a 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 0.03 to 0.04 g, and the amount enclosed in the bearing (about approx. 0.4 g) was only 7.5 to 10.0%, and only 0.5 to 1.0% of the grease leakage amount of the comparative machine. In this case, the leakage of the grease stopped to such an extent that the adhesion cannot be visually confirmed from the appearance of the rotary blade unit, and the leaked grease was only 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.

It is a figure which shows the structural example of the rotary blade unit which concerns on one Embodiment of this invention, Comprising: (a) is sectional drawing 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 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 8 Main shaft 20 Internal pressure adjustment chamber 20a Air hole 32 Cutting blade 34 Engine 36 Drive shaft G1 Drive shaft gear G2 Main shaft gear U1 Rotary blade unit

Claims (3)

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; A rotating member support unit 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,
When the internal pressure of the rotating member support unit increases, the internal air is discharged from the inside of the unit to the outside. When the internal pressure decreases, the external air flows into the unit from the outside to the atmospheric pressure. A rotating member support unit comprising an internal pressure adjusting mechanism having at least one air hole for maintaining substantially the same pressure.   The rotary member support unit is provided with an internal pressure adjustment chamber that can communicate with the outside of the rotary member support unit only by an air hole as an internal pressure adjustment mechanism. The internal pressure adjustment chamber communicates with the inside of the rotary member support unit. At least one communication hole is formed, and a lubricant reservoir for collecting and storing the lubricant enclosed in the unit is provided, and the lubricant reservoir is disposed in the air. The rotating member support unit according to claim 1, wherein the rotating member support unit is positioned closer to the other end of the main shaft than the opening of the hole and the opening of the communication hole. The rotating member support unit according to claim 1 or 2, wherein a cutting blade for cutting off the vegetation growing on the ground surface from near the root is attached to the main shaft.

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