JP2955464B2 - Sliding part structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding portion for fitting a rotary transmission member such as a shift gear to a shaft so as to be slidable, and more particularly to a structure for preventing a bush from being press-fitted.

[0002]

2. Description of the Related Art For example, in the combine mission shown in FIG.
The shift gears provided with L and 21R correspond to a rotation transmission member, and the shift gear is fitted to the shaft via a bush, so that the operation of freely rotating and sliding on the shaft is smoothly performed with little frictional resistance. I have to be.

[0003]

The shift gear has a structure in which a bush is fitted by press-fitting, and the bush and the shaft relatively rotate and slide. However, if the on and off of a sudden load that is engaged and transmitted rotationally as soon as the sliding movement is repeated is repeated frequently, the press-fitted bush may be displaced in the axial direction with respect to the shift gear in some cases. Measures have become necessary.

Therefore, as shown in FIG. 5, one end of a bush press-fitting inner peripheral surface 34a of the shift gear 34 is projected in the inner diameter direction to form a retaining portion 31, and a circlip 33 is attached to the other. That general structure was conceived. According to this means, the protrusion can be reliably prevented by the protruding wall 35 and the circlip 33. However, the sliding width and the press-fitting width of the bush 5 are reduced by the width of the protruding wall 35.
In the shift gear 34 in which the load condition is relatively severe and is installed in a limited space, it is desirable that the bush 5 has a sufficient length and press-fit width as much as possible in terms of smooth operation and durability. There appears to be room for improvement in the means of reducing the bushing length at all.

An object of the present invention is to provide a structure capable of preventing the rotation transmission member from slipping off without shortening the substantial bush length as much as possible.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a shaft and a rotary transmission member fitted on the shaft through a cylindrical bush provided between the shaft and the rotary transmission member. In the sliding part structure which is fitted so as to be relatively slidable, the inner peripheral surface of the bush is
In addition, the outer peripheral surface is set to each of the press-fitting peripheral surfaces of the rotary transmission member, and a tapered peripheral surface is formed at one end of the bush outer peripheral surface . By omitting a part, the finish
Forming a small step that projects in the smaller diameter direction than the other parts that do not omit the cutting process, and by contacting this small step with the tapered peripheral surface, the stopper part to one of the bush and the rotation transmission member is prevented. It is characterized by comprising.

[0007]

Normally, a tapered peripheral surface is formed at the end of the press-fitting peripheral surface of the bush for facilitating the press-fitting operation. For example, as shown in FIG. Without making the width of the bush 5 short, such as aligning the end of the rotation transmission member 21R and the end of the bush 5 with substantially the same surface while forming the retaining portion 31 with which the peripheral surface 5c contacts, or It is possible to reduce the number of slips.

[0008] Basically, the bush 5 is engaged and fixed to the rotary transmission member 21R by press-fitting.
It has been confirmed that the retaining function is sufficiently exerted even with a small step 28 as shown in FIG.

[0009]

As described above, the rational and compact bushing width is not reduced as much as possible by utilizing the existing taper peripheral surface for press-fitting operation to make contact with the minute step of the rotary transmission member. A sliding portion having a retaining structure was provided.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 shows a diagram of the transmission structure in the transmission case 8 of the combine, wherein 1 is an HST (hydrostatic continuously variable transmission), and 2 is an HS to which power from an engine (not shown) is input.
The input pulley T1, the output shaft 3 of the HST 1, the first transmission shaft 4 and the power transmitted from the first transmission shaft 4 to a cutting unit (not shown).

Power from the first transmission shaft 4 is transmitted to the second transmission shaft 11 via the first gear 9 and the second gear 10.
A shift gear 14 is fitted around the spline on the second transmission shaft 11, and a high-speed gear 16, a medium-speed gear 17,
And the low-speed gear 6 is fixed. Therefore, when the shift gear 14 is slid, the gear is shifted to three speeds: a high speed stage meshing with the high speed drive gear 7 meshing with the high speed gear 16, a middle speed stage meshing with the middle speed gear 17, and a low speed stage meshing with the low speed gear 6. A possible main transmission 13 is configured. The forward power is transmitted to the first transmission gear 19 that meshes with the medium-speed gear 17.

A right side gear 21R and a left side gear 21L are fitted over the support shaft 20 supporting the first transmission gear 19, and the input gears 23 of the left and right axles 22 always mesh with the left and right side gears 21R and 21L. I have. This allows
The right or left side gear 21R, 21L is connected to the first transmission gear 1
9 to perform transmission and transmission interruption operations to the left and right crawler traveling units 24 by sliding and engaging with each other, thereby forming side clutches 25R and 25L.

As shown in FIG. 4, a third gear 37 meshing with the high-speed gear 16 is rotatably fitted to the fourth transmission shaft 27 so as to be relatively rotatable. A clutch 30 is provided. The second transmission gears 26R and 26L are supported by bearings at both left and right ends of the support shaft 20, and the fourth transmission gears 29 fixed to both ends of the fourth transmission shaft 27 are connected to the second transmission gears 26R and 26L. Occluded.

Therefore, when the reverse clutch 30 is engaged while the right side gear 21R or the left side gear 21L is engaged with the right or left second transmission gear 26R, 26L,
The power from the high-speed gear 16 is in the reverse state, and
And transmitted to one traveling device 24. In this case, the other side gears 21R and 21L are connected to the first transmission gear 1
9 and is driven in the forward direction, the vehicle body turns due to a large speed difference between the left and right traveling devices 24.

A small-diameter output gear 38 is fixed to the boss portion of the first transmission gear 19, and a large-diameter third transmission gear 40 is fitted around the fourth transmission shaft 27 so as to be relatively rotatable. The gear 40 is in mesh with the output gear 38. Then, the gentle turning clutch 12 is disposed between the third transmission gear 40 and the fourth transmission shaft 27.
Is provided.

Accordingly, the right or left side gear 21R, 2R
1L is engaged with the right or left second transmission gears 26R, 26L, and the gentle turning clutch 12 is engaged.
The forward rotation power for straight traveling transmitted to the transmission gear 19 is output by the output gear 38, the third transmission gear 40, the gentle turning clutches 12 and 4.
Via the transmission shaft 27, the fourth transmission gear 29, and the right or left second transmission gear 26R, 26L, the power is transmitted to one traveling device 24 as forward rotation power reduced to one third. In this case, the other side gears 21R and 21L mesh with the first transmission gear 19 and are driven to rotate forward at a predetermined speed.
The body turns slowly due to a small speed difference between the left and right traveling devices 24.

Next, the structure of the sliding portion of the left and right side gears 21R and 21L will be described. As a representative description of the right side gear 21R, as shown in FIG. 1, the right side gear (corresponding to a rotation transmission member) 21R is fitted to the support shaft 20 via the bush 5 so as to be rotatable and slidable. Normally, the gear portion 21r of the right side gear 21R and the first spring 21 are firstly moved by the winding spring 18 externally fitted to the support shaft 20.
The transmission gear 19 is urged so as to mesh with the inner gear portion 19a. Then, the right side gear 21R is wound around the spring 1
8 to the right side gear 21R
Can be operated so that the claw portion 21a of the right second transmission gear 26R and the claw portion 26a of the second right transmission gear 26R are engaged.

As shown in FIGS. 1 and 2, the cylindrical bush 5 has an inner peripheral surface 5a on the slide peripheral surface with respect to the support shaft 20, and an outer peripheral surface 5b with the press-fit mounting peripheral surface on the right side gear 21R. And tapered peripheral surfaces 5c, 5 at both ends of the outer peripheral surface 5b for facilitating the press-fitting operation.
c is formed. At the left end of the bush press-fitting inner peripheral surface 21b of the right side gear 21R, there is formed a small step 28 projecting in the small diameter direction, and the small step 28 and the left tapered peripheral surface 5c are brought into contact with the bush 5 and the right. A left retaining portion 31 with the side gear 21R is formed.

The right retaining portion 32 is formed by abutment of a circlip 33 fitted to the right end of the bush press-fitting inner peripheral surface 21b of the right side gear 21R and a right end surface 5r of the bush 5. Have been. The bush press-fitting inner peripheral surface 21b is a precision processed finish to be ground, but the minute step 28 is a medium finish surface before the precision processing is performed. mm
Is formed. Therefore,
The bush 5 is press-fitted from the circlip mounting side, and then the circlip 33 is fitted into the bush 5 so that the right side gear 2 is inserted.
Equipped on 1R.

[Another Embodiment] As shown in FIG. 3, the right retaining portion 32 may also be constituted by abutment between the right tapered peripheral surface 5c of the bush 5 and the very small step 36. . In other words, by omitting the grinding and finishing step of the inner peripheral surface 5a of the bush, it becomes about 0.02 to 0.04 mm.
The bush 5 is forcibly pushed through the extremely small step 36, and is fitted in a so-called fitting-fitting state. In this case, the width of the polished surface is further reduced and the circlip and the groove for the circlip are not required as compared with this embodiment, which is advantageous in terms of cost reduction and number of parts.

The retaining portion 32 on the bush press-in side is formed by caulking the transmission rotating member 21R at a plurality of positions, or
The circlip 33 may be attached to the large-diameter inner peripheral surface 39 of the rotary transmission member 21R in FIG. 2, and the bush 5 without the right tapered peripheral surface 5c may be press-fitted to increase the press-fit length. By the way, in the present application, for the sake of understanding of the drawings, the taper inclination of the tapered peripheral surface 5c and the minute steps 28 and 36 are drawn in an exaggerated manner as compared with the actual case.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a structure of a sliding portion.

FIG. 2 is an enlarged sectional view of a main part showing a mounting structure of a bush;

FIG. 3 is an enlarged sectional view of a main part showing another mounting structure of the bush;

FIG. 4 is a diagram showing a mission structure of the combine.

FIG. 5 is a sectional view showing a comparative example structure of a sliding portion.

[Explanation of symbols]

 Reference Signs List 5 bush 5b outer peripheral surface 5c tapered peripheral surface 20 support shaft 21R transmission rotating member 21b inner peripheral surface for bush press-fitting 28 minute step 31 retaining part

Claims (1)

(57) [Claims] 1. A shaft (20) and a rotary transmission member (21R) fitted on the shaft (20) via a cylindrical bush (5) provided between the shaft (20) and the rotary transmission member (21R). The bush (5) with the inner peripheral surface (5a) of the shaft (20).
, And the outer peripheral surface (5b) is set as the press-fit mounting peripheral surface to the rotary transmission member (21R), and one end of the outer peripheral surface (5b) is tapered peripheral surface (5).
c) and the rotary transmission member (21R)
Finish on one end of the bush press-fitting inner peripheral surface (21b).
By omitting part of the work, the finishing process can be omitted
Minute step protruding diameter direction than other portions not (2
8), and the contact between the minute step (28) and the tapered peripheral surface (5c) prevents the bush (5) and the rotation transmission member (21R) from being removed from one side (31).
The sliding part structure which comprises.