JPH0135145Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a roller drive device for a power lawn mower, which is equipped with a prime mover, uses power to drive a cutter, and drives rollers to travel.

This type of lawn mower uses a prime mover to rotate in a horizontal plane, and is equipped with wheels at the four corners of a housing that surrounds the cutters used for mowing the lawn.The lawn mower uses the rear wheels as drive wheels to propel itself.

By the way, there is a type in which the rear wheels are constructed of rollers, and when the rollers are used as driving wheels, the rollers are located behind the cutter, so that the cut grass surface is pressed and shaped by the rollers.

Conventional roller-driven lawn mowers have a roller drive mechanism located on one side of the roller in the axial direction, so the width of the roller drive mechanism is the width of the roller drive mechanism in the left-right direction (roller axial direction) relative to the lawn mower body. It has no choice but to be biased toward one side. As a result, one side of the grass surface cut with the cutter is outside the pressure shaping range of the rollers, resulting in a problem that some pressure shaping remains.

Therefore, in order to improve the above problem, when trying to completely overlap the width of the mowed roller with the lawn cutter, the drive mechanism has no choice but to protrude outward from one end of the roller. The rear portion partially bulges out, making it unnecessarily wide, making the overall size larger, and making it ungainly in appearance.

By the way, conventional drive mechanisms use a gear train for the final drive, and a gear clutch for switching between self-propelled and idle-propelled modes, resulting in a complex structure and large weight. There is a disadvantage.

The present invention was made to improve the above-mentioned problems, and its purpose is to suppress the roller drive mechanism within the width of the main body, align the roller with the mowed surface of the lawn cutter, and eliminate the unformed shape left by the roller. lost,
To provide a roller drive device for a power lawn mower, which achieves the compact width of the lawn mower while fully demonstrating the functions of the rollers, and achieves the above while simplifying and reducing the weight of the drive mechanism.

In order to achieve the above object, the present invention divides the roller forming the rear driving wheel into two parts at the axial middle part, and arranges a drive mechanism in the middle part of the roller to drive the left and right roller halves. Fit the mechanism to the fixed support shaft,
Its gist is that it consists of a mechanism consisting of a cylindrical drive member connected to the roller split halves, a sprocket for this, a sprocket that connects to and separates from the drive member from the engine by means of a clutch, and a chain.

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a lawn mower 1, in which an engine 3 is mounted above a housing 2 that houses a cutter (not shown), a handle 4 is extended at the rear and upper part of the housing 2, and a handle 4 is installed on the left and right sides of the front of the housing 2. A grass bag 6 is provided at the rear of the housing 2 to store grass that has been cut by a cutter that is rotatably driven in a horizontal plane. The rollers 7 constitute a rear wheel, which is a driving wheel.

The details of the rollers 7 forming the drive wheels are shown in Figures 2 to 4.
As shown in the figure, its length is approximately equal to the diameter of the stub, and is set approximately equal to the width of the grass.

The roller 7 consists of left and right halves divided at the middle part of the axial length, and the halves 8 and 9 are drum-shaped,
A cylindrical main body 802, 902 having an end piece 801, 901 at each outer end and extending in each axial direction from the end piece.
Equipped with. A support shaft 10 is passed between the radial center portions of the end pieces 801 and 901 to rotatably support the roller halves 8 and 9 via bearings 11, and both ends of the shaft 10 are connected to the rear ends of the left and right parts 12 and 12. The nut 102 is passed through the boss parts 122, 122 provided on the inner surfaces of the shafts 121, 121, and is screwed onto the bolt part 101 provided at the end of the shaft to be connected to the rear end of the stay, and the shaft is fixed. The above stays 12, 12 are configured such that their bases are supported by vertical movement mechanisms 13, 13, and the amount (height) of the lawn to be mowed can be adjusted by adjusting the height of the rear part of the housing 2. .

Cylindrical body 80 of the left and right halves 8 and 9 of the roller 7
2,902 is rotatably supported concentrically with respect to the support shaft 10, and the opposing inner ends 803, 903 of the main bodies 802, 902 are spaced apart in the axial direction to form a gap S therebetween, and the transmission An arm portion 141 formed at the rear end of the case 14 is exposed. The rear end of the case 14 has a joint structure of a main body 142 and a cover 143, and the rear end of the arm 141 is provided with a bearing boss 144 facing between the axially intermediate parts of the main bodies 802 and 803. Bearing 1 in the middle of
03 and 103, the middle portion of the drive cylinder 15 is rotatably fitted. Drive tube 15
A final driven sprocket 151 is provided at the axial center of the sprocket 151, and the sprocket 151 has its boss portion 152 axially regulated between the left and right stepped portions 145, 145 of the rear end portion 144 of the arm portion. Facing inside the boss portion 144. The arm portion 141 extends from the gap S in an upwardly inclined manner, and extends from the base portion 146.
A driven bevel gear 161 is freely fitted onto a shaft 16 parallel to the support shaft 10 mounted therein, and the shaft 16 is connected to bearing portions 146 provided on the left and right sides of the base portion 146.
, 146 rotatably supports both ends of the shaft 1.
On the 6th turn, a drive sprocket 162 is coaxially spaced apart from the gear and fitted by spline engagement or the like, and a clutch 16 is installed between the gear 161 and the sprocket 162.
3, the clutch 163 is spline-engaged between the gear and the sprocket, and has a shifter 164 movable in the axial direction, a protrusion 165 protruding from the shifter 164 in the direction of the gear, and a clutch 163 that engages with and disengages from the protrusion. gear 161
The gear 161 and the sprocket 162 are engaged when the shifter 164 is moved to the left in the figure, and the figure shows the clutch-off state. shifter 16
4 is operated by the operating mechanism 21 shown by the chain line in FIG.
The operating mechanism 21 includes a pin 211 that rotates a shift fork (not shown) that engages with a groove 167 of the shifter 164, a link 212 that rotates this, a transmission member 213 that swings the link 212 with a cable or rod, etc. is composed of A drive bevel gear 171 at the rear end of the propulsion shaft 17 extending rearward from the engine faces the base 146, and the gear 171 meshes with the bevel gear 161 to transmit engine power to the bevel gear 161. The drive sprocket 162 and the driven sprocket 151 are connected by a chain 19, and the transmission and drive mechanism described above is housed in the case 14.

Engagement parts 153, 153 such as splines are provided at both axial ends of the drive cylinder 15, and the holder 80 is attached to the engagement parts 153, 153 such as splines.
4,904, the bases 805, 905 are fixed to the inner diameters of stays 806, 906 extending radially outward;
The outer diameter portion of the stay is fixed to the inner circumferential wall of the inner end portion of the main body 802, 902, and the stay 806, 906 may be shaped like a funnel disk or may be composed of a plurality of members provided radially.

As described above, the engine power transmitted by the sprocket 151 is transmitted to the drive cylinder 15 and the holders 804 and 904.
It will be transmitted to the main bodies 8 and 9 via.

Note that the arm portion 1 of the case 14 facing the gap S
The boss portion 144 of 41 is provided with mounting boss portions 147, 147 in the front and lower lower halves of the boss portion 144, and the boss portions 147,
The main body 802, 902 has a channel shape in cross section at 147.
A spacer 18 having a partially arcuate bottom piece 181 concentric with the spacer 18 is attached, and as shown in FIGS. The spacer 18 is fastened together with a bolt 183 and a nut 184 that connect the lower end portions of the boss portions 147, 147 on the case side and the cover side in a sandwiching manner. Such spacer 1
The lower piece 181 of No. 8 faces between the gap S mentioned above, has a slightly smaller width than the width of the gap S, and has a width that is equal to the outer diameter of the opposing inner ends 803, 903 of the main bodies 802, 902 and the outer diameter of the bottom piece 181. The lower half of the gap S is covered by the bottom piece 181 of the spacer 18, and the raised pieces 182, 182 protrude inward in the radial direction of the gap S by a predetermined amount. In the figure, numerals 20 indicate bolts that connect the case body and the cover.

Next, the functions and effects will be explained in detail. In the above, the roller 7 is composed of left and right halves, the drive system is exposed between the left and right halves 8 and 9, and the final drive section is connected to the main bodies 8 and 9. Because it is housed between the inner ends, unlike installing the drive mechanism at the roller end, the mowing width of the cutter and the width of the roller match without causing the drive mechanism to bulge out to the side, within the width of the lawnmower body. , it is possible to plan for shaping by running the full width of the cutter while achieving compactness. Then, while dividing the roller, the gap facing the drive mechanism is closed with a spacer, thereby shaping the intermediate portion of the roller, so that the full width of the cutter can be shaped while dividing the roller.

By the way, the engine power to the propulsion shaft 17 is in gear 1.
71 to the gear 161, and in the state shown in FIGS. 2 and 3, the clutch 163 is off and the gear 161 is idling, but the operation of the operating mechanism 21 causes the slider 164 to move to the left in the figure. By causing the protrusion 165 to engage with the recess 166, the power of the gear 161 is transmitted to the slider 164, driving the shaft 16, and the sprocket 162 is driven.
The cylindrical drive member 15 is driven via the chain 19 and sprocket 151, and the left and right halves 8 and 9 are driven.

In the above, the left and right halves 8 and 9 are respectively supported at their outer and inner ends with respect to the support shaft 10, so that the support is reliable and smooth driving is possible, and the drive system is Since a chain drive mechanism is adopted, tension and relaxation of the chain act on the support shaft 10 alternately, tightening and loosening the chain, but both ends of the support shaft 10 in the axial direction are fixed, and the span between them is long. Since the cylindrical drive member 15 is arranged on the spindle and is fitted onto the spindle with a span at both ends in the axial direction, the bending force caused by this is also supported at two points in the middle, and load fluctuations due to the chain mechanism are avoided. The support shaft can be made stronger against the ground. Therefore, even if the chain drive mechanism is used to simplify the structure and output power at the intermediate portion of the support shaft, the strength of the support shaft can be maintained while reducing the diameter, which is mechanically advantageous.

In the state shown in the figure, the clutch 163 is off, so the roller 7 is connected to the halves 8 and 9, the cylindrical drive member 15, the chain 19, and the sprockets 151 and 162.
It is possible to carry out a hand-pull run without using power, thereby making it possible to carry out a smooth trial run.

The present invention has many advantages as described above.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the lawn mower, FIG. 2 is a cutaway front view of the main part of the roller, FIG. 3 is an enlarged view of the main part, and FIG. 4 is a longitudinal sectional side view of the main part. In addition, in the drawing, 1 is a lawn mower, 7 is a roller, 8, 9
1 is a divided half body, 803 and 903 are mounting members, 10 is a support shaft, 15, 16, and 19 are drive mechanisms, 14 is a transmission case, and S is a gap.

Claims (1)

[Scope of Claim for Utility Model Registration] Equipped with a prime mover, the prime mover rotates a cutter to perform lawn mowing work, and the driving force of this prime mover is also transmitted to rollers forming drive wheels for self-propelled driving. In the power lawn mower, the roller is divided into two parts at an axially intermediate portion, a gap is provided between each divided half, and the outer periphery of the roller support shaft facing from this gap has a sufficient length, and A cylindrical drive member having a driven sprocket is rotatably fitted to the outer peripheral surface of the central portion, and each of the divided halves has a mounting member attached to the inner peripheral surface of the opposing inner end of each of the cylindrical drive members. The outer end wall of the split half is rotatably attached to a roller support shaft, and the output of the prime mover is connected to the driven sprocket via a clutch mechanism. A roller drive device for a power lawn mower, characterized in that a chain is attached to a drive sprocket that can freely transmit power.