JPH084346Y2 - Transmission equipment for work vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a work vehicle transmission device suitable for a small work vehicle such as a lawn mower.

[Conventional technology and its problems]

For small work vehicles such as lawn mowers, it is required to make the transmission device as compact as possible, and various measures have been devised for that purpose, but the inner wall surface of the motion case supporting the rotating shaft via bearings. The bearings have been designed to support the bearings over their entire length, as in a transmission of a full-scale work vehicle.

Therefore, the installation space for the device components installed in the mesh case near such a bearing is secured by expanding the mesh case.

[Invention task]

This invention focuses on the fact that a simple transmission device for a small work vehicle is often provided with a rotary shaft that rotates only in one direction, and the basic performance of the bearing part on the inner wall of the motion case is reduced. It is formed so as to provide a member installation space in the mesh case without
An object is to obtain a compact transmission device.

[Means for solving the problem]

To this end, the present invention, as illustrated in the attached drawings, includes two rotating shafts 2, 3 which are interlockingly connected by meshing gears.
And the two rotary shafts 2, which rotate only in one direction,
In the work vehicle transmission device equipped with 3,
The following measures were taken.

That is, at least one of the two rotary shafts 2 and 3 (both rotary shafts 2 and 3 in the illustrated example) is supported by bearings 6 and 7 on the inner wall surface of the wall of the motion case. The cutout portions 10 and 11 for leaving a part of the length direction and the circumferential direction in a non-supported state are provided on the half-shaft side of the rotating shafts to which the rotational reaction force in the gear meshing portion is not applied, An empty space attached to the inside of the case is constructed as an installation space for the device components 13a, 13c, 14, 25.

In the example shown in the figure, the drive shaft 2, the speed change shaft 3, and one end of each of the two rotary shafts are supported by the sleeve bearings 6, 7 at the bearing portions, respectively, and the cutout portions 10, 11 according to the present invention are provided. Has been. The drive shaft 2 and the speed change shaft 3 respectively include three drive gears 4I, 4II, 4III fixedly installed on the drive shaft 2 and three speed change gears 5I, 5II, 5III loosely fitted on the speed change shaft 3. The meshing gears 5I, 5II, 5III are selectively coupled to the gearshift shaft 3 and are interlocked and coupled at one gear ratio among three different gear ratios, while rotating in different directions. Is the axis of rotation that rotates only in one direction.

Further, in the illustrated example, the speed change shaft 3 is formed as a hollow shaft, and an axle 8 which is coupled to the speed change shaft 3 via the clutch 9 is provided so as to penetrate the speed change shaft 3, and the speed change shaft 3 is directly connected to the axle 8. The bearing 7 is directly supported between the axle 8 and the bearing portion on the inner wall surface of the transmission case, but when the clutch 9 is engaged, the transmission shaft 3 and the axle 8 are integrated in the same direction. The bearing which bears the bearing 7 due to the rotation essentially serves as the bearing for the transmission shaft 3.

Further, in the example shown in the figure, the case 1 is divided into upper and lower case halves, and the bearings 6 and 7 described above are held by the semicircular bearings of the mating surfaces of the case halves for the respective halves in the circumferential direction. The bearings are formed by combining the semicircular bearings of the two case halves. The cutout portion 10 is provided by making the length of the semicircular bearing portion of the upper case half portion smaller than the length of the bearing 6, and the cutout portion 11 is the semicircular shape of the lower case half portion. It is provided by making the length of the bearing portion smaller than the length of the bearing 7.

[Action]

FIG. 2 is a schematic cross-sectional view of the drive shaft 2 and the speed-change shaft 3 which are cut in a cross section, and the drive gears 4I-4III are shown.
And gears 5I-5III are represented by gears 4,5, and gear shaft 3
Is drawn as a close-fitting axis. The gears 4,5 and the shafts 2 and 3 each rotate in one direction of the arrow shown.

The rotational reaction force generated by the meshing rotation of the gears 4 and 5 is as shown by the arrow P ₁ on the gear 4 side and as shown by the arrow P ₂ on the gear 5 side in the rotation direction of the gears 4 and 5. Then, the gear rotation reaction force indicated by the arrow P ₁ is applied to the drive shaft 2, and the gear rotation reaction force indicated by the arrow P ₂ is applied to the transmission shaft 3. As described above, in the cylindrical bearing portion of the inner wall surface of the transmission case, each of the cutout portions 10 and 11 is provided on the half side of each of the rotating shafts to which the gear rotation reaction forces P ₁ and P ₂ are not applied. ing.

In this way, since the notch parts 10 and 11 are provided in the shaft half part where the gear rotation reaction forces P ₁ and P ₂ are not applied,
This is because the stable support of the shafts 2, 3 via 6,7 does not impair the function, and the forming range of the notches 10,11 is limited to a part of the lengths of the bearings 6,7. The shafts 2 and 3 do not shake together with the bearings 6 and 7.

If the above-mentioned cutout portions 10 and 11 are provided on the bearing portion of the wall surface of the case, the case inner wall portion including the cutout portions 10 and 11 will be recessed in a groove shape. Part 10,1
The space provided by the 1 in the mission case occupies a considerable area.

〔Example〕

The illustrated embodiment relates to an example of implementing the present invention as a transmission device for a lawn mower, in which the left and right rear wheels (not shown) are provided at the extending end of the axle 8 extending left and right from the transmission case 1. It is supposed to be equipped with.

As is usual with lawnmowers, when lawn mowing work is performed, the left and right rear wheels drive the lawn mower forward and self-propelling, and the worker walks while holding the steering wheel at the rear of the lawn mower. When the lawn mower is moved backward, the operator pulls the steering handle backward while the clutch 9 is cut off and the rear wheels are not driven. Therefore, the transmission device shown in the figure is configured to have only the forward shift speed and not the reverse shift speed, as is common in lawnmowers.

The upper case half of the transmission case 1 is equipped with a vertical input shaft 19 through a pair of ball bearings 17 and 18, and the upper end of the input shaft 19 receives power from an engine (not shown). A pulley 20 for receiving is installed. Input shaft 19
A small bevel gear 21 is integrally provided at the lower end of the large bevel gear 21, and a large bevel gear 22 meshed with the small bevel gear 21 is fixedly installed on the drive shaft 2.

FIG. 1-7 shows the first embodiment, and as shown in FIG. 1, the drive shaft 2 is supported at its one end by the sleeve bearing 6 on the bearing portion having the cutout portion 10. In addition, the other end is supported via a sleeve bearing 24 by a bearing which does not include a cutout portion on the inner wall surface of the mesh case. The recessed groove-shaped space provided on the inner wall surface in the mesh case by the notch 10 is formed by the following retaining plate 25, which is one of the components of the apparatus, that is, the screw bolt 12. It is used as an installation space for a retaining plate 25 fixed to the inner surface of the top wall of the mission case 1 and retaining the ball bearing 18. That is, the retaining plate 25 is the first
As shown in the figure and FIG. 6 in which a part of the upper half of the split split case 1 is turned upside down to show the inner surface side, a part of the peripheral edge of the retaining plate 25 is in the space. It is arranged so that it will face.

As described above, the hollow speed-changing shaft 3 is supported by the mesh case 1 through the axle 8 that penetrates the shaft.
As shown in FIG. 4, one end of the axle 8 is supported by a sleeve bearing 7 and is supported by a bearing portion having the cutout portion 11, and the other end is supported by a sleeve bearing 26. The upper cutout portion is supported by a bearing portion not provided.

As shown in FIGS. 3 and 4, the speed change gear 5I is provided on the speed change shaft 3.
-5III and the clutch sleeve 9a of the clutch 9,
A shifter sleeve 27 for shifting gears is provided.
Further, as shown in FIG.
A pair of shift keys 29 that are slidably housed in a pair of long slot 28
And the shift keys 29 are integrally slidably attached to the shifter sleeve 27. The shift key 29 constitutes, for example, a shift member of a key shift type transmission known from U.S. Pat.No. 3,812,735 and the like. Alternatively, it is connected to the transmission shaft 3.

As shown in FIGS. 3 and 4, the shift fork 30 rotatably supported on the shift case 1 about the vertical axis can be slidably displaced on the shift shaft 3 by the rotational displacement. Is engaged with the sleeve 27. A detent arm 13a made of a spring plate shown in FIG. 3-5 is locked to the lower end portion of the shift fork 30 so as to rotate integrally with the shift fork 30. The detent arm 13a extends toward the inner bottom surface of the mission case 1. A ball 13b for detent is held at the tip of a certain detent arm 13a. A detent plate 13c having detent holes 31I, 31II, 33III into which balls 13b are fitted at its half portions is fixedly installed on the inner bottom surface of the transmission case 1, whereby the shifter sleeve 27 is attached. The detent means 13 for constraining the position at each of the above gear shift action positions is configured. As is apparent from FIGS. 4 and 5, and FIG. 7 showing the lower half of the split split case 1 as seen from above, the cutout portion 11 allows the inside of the shift case to be removed. The recessed groove-shaped space provided on the inner wall surface of the detent plate 13c faces a part of the detent plate 13c so that the detent arm 13a can be rotated into the space. Detent arm 13a and detent plate 13c
Is used as an installation space.

As shown in FIG. 3, the shift fork 30 has a bulging portion 30a extending in the direction opposite to the shifter sleeve 27 at the central portion in the lengthwise direction of the straight portion, so that the thickness of the portion can be secured. On the contrary, the center line of the straight portion or the rotation axis Y
Is provided as close to the shifter sleeve 27 side as possible. In the lawn mower equipped with the illustrated transmission device, the hanging wall DN of the machine frame which positions the back wall portion 1a of the movement case 1 as much as possible toward the front side, and therefore, is located behind the back wall portion 1a. This is because the intention is to move it as far forward as possible to avoid the problem that the driver's shoe tip hits the lower part of the hanging part. The shift fork 30 is rotatably operated around the axis Y through the shift arm 33 which is locked to the fork 30 on the upper surface side of the shift case 1, and the axis Y is moved to the shifter sleeve 27 side as described above. Since they are arranged close to each other, the distance L between the fulcrum of the shift fork 30 and the point of action on the shifter sleeve 27 is made smaller by that much, and the rotational operation force of the shift fork 30 is correspondingly reduced. ing.

The clutch 9 is provided with the clutch sleeve 9a, which is slidably displaced by the rotational displacement of the clutch fork 35, and is an appropriate mechanical clutch, for example, a ball that selectively connects the hollow transmission shaft 3 and the axle 8 to the clutch. It is configured as a ball clutch or the like having a well-known structure that includes a ball that can be displaced between a clutch insertion position and a cutting position by sliding displacement of the sleeve 9a.

In FIG. 1, reference numeral 36 denotes a thrust sleeve installed on the drive shaft 2 by applying both ends to the large bevel gear 22 and the flange portion 6a at the end of the sleeve bearing 6. The thrust generated is received by the inner wall surface of the mesh case 1 via the collar 6a.

Next, the second embodiment shown in FIG. 8 will be explained. In this embodiment, the retaining plate 25 provided in the first embodiment is used.
The corresponding collar 14 is formed to have a thickness and outer diameter larger than that of the retaining plate 25, and the bearing 18 is retained by the collar 14, and in addition, the collar 14 is used as a large bevel gear.
The collar 14 receives the thrust generated by the meshing rotation of the bevel gears 21 and 22 against the end face of 22. Therefore, the first
A thrust sleeve corresponding to the thrust sleeve 36 shown in the figure is removed from the drive shaft 2.

That is, in the second embodiment, a void space provided in the mesh case is used by providing the notch portion 10 as an installation space for the collar 14 having a large size that also serves as a bearing dropout and a thrust receiver. The structure of the other parts of the second embodiment is made equal to the corresponding parts of the first embodiment.

[Effect of device]

In the transmission device for a work vehicle according to the present invention, the cutout portion 1 provided on the bearing portion on the inner wall surface of the transmission case 1
0 and 11 are provided on the bearings for the rotating shafts 2 and 3 that rotate only in one direction. It does not occur and does not deteriorate the basic performance of the bearing part.

And since the present invention utilizes the voids provided in the mission case by providing such cutouts 10 and 11 as the installation space for the device constituent members 13a, 13c, 14 and 25,
To provide a transmission device that is extremely suitable for a small work vehicle by making the transmission device compact so that it is not necessary to provide an expansion portion that is conventionally provided in the transmission case for installing members. .

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing the first embodiment, FIG. 2 is a schematic cross-sectional view of a part of the same embodiment, and FIG. 3 is III of FIG.
-Partially omitted cross-sectional view taken along the line III, and Fig. 4 is IV-I in Fig. 3.
FIG. 5 is a sectional view taken substantially along the line V, FIG. 5 is a partially omitted sectional view taken along the line VV of FIG. 4, and FIG. 6 is a partial upside-down view of the upper half of the half split case. FIG. 7 is a perspective view showing a part of the case half on the lower side of the above-mentioned mesh case, and FIG. 8 is a vertical sectional front view showing the second embodiment. 1 ... Mission case, 2 ... Drive shaft (rotating shaft), 3
...... Variable shafts (rotary shafts), 4I, 4II, 4III …… Drive gears, 5I,
5II, 5III …… Speed change gears, 6,7 …… Sleeve bearings,
8 ... axle, 9 ... clutch, 10,11 ... missing part, 12 ...
… Screw bolts, 13 …… detent means, 13a …… detent arms, 13c …… detent plates, 14 …… collars, 15 …… screw bolts, 25 …… prevention plates.

Claims (1)

[Scope of utility model registration request] 1. Two rotating shafts interlockingly connected to each other by meshing gears, each rotating in only one direction.
In a work vehicle transmission device having two rotary shafts, at least one of the rotary shafts (2, 3) is supported by bearings (6, 7) via a bearing (6, 7). The bearing part has a notch (10,1) that leaves a part of the bearing in the longitudinal and circumferential directions in an unsupported state.
1) is provided on the half of the rotating shafts where no rotational reaction force is applied at the gear meshing portion, and the voids provided by the notch portions (10, 11) in the mesh case are the component members of the device ( 13a,
13c, 14,25) installation space for work vehicles.