JPH066750U - Bearing structure of cutter shaft for lawn mower - Google Patents

Abstract

(57) [Summary] [Structure] Circular grooves 23 and 24, which serve as rails for the balls 40, are provided near both ends of the bearing portion 22 of the cutter shaft 21. The ball receiving portion 3 on the small diameter side of the tapered housing 30 made of a metal plate
2 and the plurality of balls 40 supported by the retainer 41 in the circumferential groove 23. A lid 34 made of a metal plate is fixed to the large diameter side of the housing 30, and a plurality of balls 40 supported by a retainer 41 are fitted in the ball receiving portion 33 on the inner circumference of the lid 34 and the circumferential groove 24. The oil seal 42 is fixed to the outer ends of the ball receiving portions 32 and 33, and the lip 44 of the inner periphery thereof is brought into contact with the outer periphery of the bearing portion 22. [Effect] By using the ball receiving portion 32 of the housing 30, the ball receiving portion 33 of the lid 34, the circumferential grooves 23 and 24 of the bearing portion 22, and the ball 40 to form a bearing without using a ready-made ball bearing, it is possible to reduce the weight. The bearing structure of the rotary cutter can be easily obtained.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to the structure of a bearing that rotatably supports the cutter shaft of a lawn mower used for purposes such as cutting the lawn to a certain height.

[0002]

[Prior art]

 4 and 5 show a conventional cutter shaft mounting structure for a lawnmower. In this figure, reference numeral 1 is a taper-shaped bearing housing integrally formed of cast iron or the like, and has a flange 2 on the large diameter side. Ball bearings 3 and 4 support outer rings of the bearings 3 and 4 by bearing receiving portions 5 and 6 on inner circumferences of both ends of the housing 1. The inner rings of the bearings 3 and 4 have a one-step smaller diameter on both ends of the cutter shaft 7. It is supported by the bearing receiving portions 9 and 10.

Reference numerals 11 and 12 denote oil seals, which are made of rubber with a core such as a thin steel plate, the outer circumferences of which are brought into close contact with the receiving portions 5 and 6, and the inner lips 13 and 14 are attached to the oil shutters 15 and 16 respectively. Contact the outer circumference of.

The oil shutters 15 and 16 are metal rings, and a rubber layer is provided on the inner circumference as shown in FIG. 5, and the rubber layer is in close contact with the outer circumferences of the bearing receiving portions 9 and 10. In the case of this conventional technique, the housing 1 is fixed to the cutter cover of the lawn mower with the small diameter side down, using the flange 2, and the lawn mowing cutter is attached to the cutter attaching portion 17 which is the lower end. The V-pulley is fixed to the pulley mounting portion 19 that has become.

[0005]

[Problems to be solved by the device]

 In the above-mentioned conventional example, since the bearing housing 1 is a cast product, the bearing housing 1 becomes heavy, and the work is troublesome. That is, the bearing receiving portions 5 and 6 provided at both ends of the shaft hole passing through the center of the housing 1 must be concentric, and must be precisely finished so that the outer rings of the bearings 3 and 4 can be accurately fitted. Also, the bearing receiving portions 9 and 10 into which the inner rings of the bearings 3 and 4 are fitted are formed. However, since the receiving portions 9 and 10 are also required to be concentric and have accurate dimensions, precise polishing must be performed. Therefore, it is necessary to provide the escape groove 20 of the grinder as shown in FIG.

Further, if the lips 13, 14 of the oil seals 11, 12 are directly contacted with the bearing receiving portions 9, 10, the radial width of the oil seals becomes large, so that the wall thickness is almost the same as the inner ring of the bearing. There is a problem that the ring-shaped oil shutters 15 and 16 are required. An object of the present invention is to solve the problems of the conventional bearing structure as described above, and to provide a bearing structure which is simple in working and lightweight.

[0007]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention provides a ball receiving circumferential groove on the outer circumference near both ends of a bearing portion of a lawn mower cutter shaft, and installs a small-diameter side end portion of a tapered housing made of a metal plate. A plurality of balls supported at appropriate intervals by a retainer were rotatably fitted between the ball receiving part that was bent in an arc shape and the circumferential groove on the cutter mounting side of the bearing part. The lid is made of a metal plate and is fixed to the center of the opening. A bearing structure for a cutter shaft for a lawn mower in which a plurality of supported balls are rotatably fitted and a seal is interposed between the outer end of each ball receiving portion and the outer circumference of the end portion of the bearing portion.

[0008]

【Example】

 In the embodiment shown in FIGS. 1 to 3, reference numeral 21 is a cutter shaft for lawn mowers, and a large diameter portion is used as a bearing portion 22, and circumferential grooves 23, 24 having an arcuate section for ball reception are provided on the outer periphery near both ends thereof.

Further, a cutter attachment portion 25 and a pulley attachment portion 26 are integrally provided concentrically at both ends of the bearing portion 22, and a lawn mowing cutter and a V-pulley which are not shown in these drawings are provided with a serration or the like. Use and fix.

Reference numeral 30 denotes a tapered housing formed by press-molding a steel plate. A flange 31 is formed on the large diameter side of the housing, and a ball receiving portion bent toward the inside in an arc shape of about 1/4 circle on the small diameter side. 32 is formed.

A lid 34 made of the same material as the housing 30 is attached to the outer side of the flange 31 so as to overlap. Around the center hole of the lid 34, a ball receiving portion 33 similar to the ball receiving portion 32 is formed by bulging outward by pressing. Then, the flange 31 and the lid 34 are provided with a plurality of bolt insertion holes 35 and 36 at the same position.

For the cutter shaft 21, the housing 30, and the lid 34, for example, high carbon chrome bearing steel such as SUJ2 is used. Then, as shown in FIGS. 2 and 3, induction hardening is performed on the inner sides of the ball receiving portions 32 and 33, the circumferential grooves 23 and 24 of the bearing portion 22 and both side portions thereof to provide hardened layers a and b having high hardness, This part is used as the bearing raceway for polishing.

Reference numeral 40 is a ball made of the same material as the cutter shaft 21 and the like, a plurality of which are fitted between the circumferential grooves 23 and 24 and the ball receiving portions 32 and 33, and are retained at a constant interval by the retainer 41.

Reference numeral 42 denotes an oil seal made of rubber, which is obtained by embedding the inside of a holding ring 43 made by pressing a thin steel plate into the oil seal 42 and baking it, and forming a plurality of lips 44 on the inner circumference. This oil seal 42 fits the outer circumference of the retaining ring 43 to the outside of the ball receiving portions 32, 33 and makes the outer circumference of the inner oil seal 42 closely contact with the inner circumference of the end portions of the ball receiving portions 32, 33, thereby providing a lip on the inner circumference. 44 is brought into close contact with the hardened layer b 1 on the outer periphery of the end of the bearing portion 22.

Further, the bolts 45 inserted into the respective insertion holes 35 and 36 are inserted into the insertion holes of a cutter cover (not shown) and tightened with nuts, etc. to integrally connect the housing 30, the lid 34 and the cutter cover. . During this tightening, the positional relationship between the flange 31 and the lid 34 is adjusted by the gap between the insertion holes 35, 36 and the outer circumference of the bolt 45, and the ball receiving portions 32, 33 naturally become concentric.

Reference numeral 46 in FIG. 1 denotes a filler made of closed-cell foamed plastic, the outer periphery of which is tapered so as to be in close contact with the inner surface of the housing 30, and the inner periphery of which has a proper gap between the bearing portions 22. It has a diameter. The filling 46 reduces the space volume in the housing 30 and reduces the amount of grease required to fill.

[0017]

【effect】

 As described above, this invention is lighter than a cast product because the tapered housing and the lid attached to the large diameter side of this housing are pressed products, and the end of the housing on the small diameter side is A plurality of balls supported by retainers at appropriate intervals were rotatably fitted between the ball receiving part and the circumferential groove on the cutter mounting side of the bearing part, and the ball receiving part formed in the central opening of the lid and the pulley mounting The cutter shaft is rotatably supported without using a ready-made ball bearing by rotatably fitting a plurality of balls supported by a retainer at appropriate intervals between the side circumferential grooves. By fitting the balls fitted in the circumferential grooves of the bearing part to the ball receiving part of the housing and the ball receiving part of the lid, it is possible to align them naturally, and in this state, connect the housing flange and the lid. Because it is easy to assemble.

Further, since there is no inner ring and outer ring unlike the conventional off-the-shelf ball bearing, the lip of the oil seal attached to the housing can directly contact the bearing portion. Therefore, there is no need for a ring-shaped oil shutter for receiving the lip of the oil seal as in the past, and there is an effect that the size is reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of an embodiment.

FIG. 2 is an enlarged vertical side view of one ball receiving portion of the above.

FIG. 3 is an enlarged vertical sectional side view of the other ball receiving portion.

FIG. 4 is a vertical sectional side view of a conventional example.

FIG. 5 is an enlarged vertical sectional side view of the bearing mounting portion of the above.

[Explanation of symbols]

 21 Cutter Shaft 22 Bearing Part 23 Circumferential Groove 24 Circumferential Groove 30 Housing 32 Ball Receiving Part 33 Ball Receiving Part 34 Lid 40 Ball 41 Retainer 42 Oil Seal 44 Lip

Claims (1)

[Scope of utility model registration request] 1. A ball having a taper housing made of a metal plate and having an end portion on the small diameter side bent inward in an arc shape by providing peripheral grooves for receiving balls on outer circumferences near both ends of a bearing portion of a cutter shaft for a lawn mower. A plurality of balls supported by retainers at appropriate intervals are rotatably fitted between the receiving part and the circumferential groove on the cutter mounting side of the bearing part, and the center of the lid made of a metal plate fixed to the large diameter side of the housing. A plurality of balls supported by a retainer at appropriate intervals are rotatably provided between the ball receiving portion, which is formed by bending the periphery of the opening outward and is bent inward in an arc, and the peripheral groove on the pulley mounting side. A bearing structure for a cutter shaft for a lawn mower in which a seal is interposed between the outer end of each ball receiving portion and the outer circumference of the end portion of the bearing portion.