JPH0732220Y2 - Driveline structure in a tractor with a hydrostatic transmission - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a drive system structure in an agricultural tractor having a hydrostatic transmission.

[Conventional technology]

In a hydrostatic transmission, a variable displacement pump with a movable swash plate and a constant discharge motor with a fixed swash plate are connected by a closed hydraulic circuit, and the variable displacement pump is rotatably driven by an engine or the like. The output of the variable displacement pump is changed from zero to positive or negative even if the input rotation speed and rotation direction are constant by changing the angle of the movable swash plate of the variable displacement pump. The rotation speed of the constant capacity motor changes continuously from zero to the forward or reverse direction. Therefore, it has the advantage of being able to freely control the speed from zero to the maximum forward / reverse speed by simply pushing and pulling the lever back and forth while the engine is running at full speed, so it is used for agricultural tractors that require precise speed control. It started to come.

[Problems to be solved by the device]

However, the above-mentioned hydrostatic transmission generates a considerable amount of noise, and since it has been conventionally incorporated in the drive system of a tractor without a cover, the noise was intense.

Also, the distance between the main output shaft of the hydrostatic transmission and the PTO output shaft differs from the distance between the main input shaft and the PTO input shaft of the rear transmission used in the conventional gear drive system, and the hydrostatic transmission also depends on the size of its output. Since there are various gaps between the main output shaft and the PTO output shaft, it was necessary to combine a rear transmission that matched the gap between the main input shaft and the PTO input shaft with the distance between both output shafts of the installed hydrostatic transmission.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to improve the problems. To reduce the noise generated by a hydrostatic transmission, the main output shaft and the PT
O For various types of hydrostatic transmissions with different output shaft intervals, it is possible to combine a predetermined rear transmission with a fixed distance between the main input shaft and the PTO input shaft.
An object of the present invention is to provide a drive system structure in a tractor equipped with a hydrostatic transmission.

[Means for Solving the Problems]

To achieve the above object, the present invention provides a drive system structure of a tractor in which a hydrostatic transmission is interposed between an output shaft of an engine and a rear transmission,
Inside the core misalignment connecting part that connects the main input shaft and PTO input shaft of the rear transmission with a predetermined shaft interval to the main output shaft and PTO output shaft of various hydrostatic transmissions with different intervals from the above two shafts, respectively. The constituted intermediate transmission case is interposed between the clutch housing and the rear transmission case, and the hydrostatic transmission is mounted on the front surface of the intermediate transmission case and housed in the clutch housing.

[Action]

Since the hydrostatic transmission that generates noise is housed in the clutch housing, the external diffusion of noise is blocked, resulting in quietness.

Also, by just aligning the hydrostatic transmission side of the misaligned connection part configured in the intermediate transmission case with the main output shaft and PTO output shaft distance of the hydrostatic transmission to be used,
Various hydrostatic transmissions with different outputs can be combined with a rear transmission with a fixed gap between the main input shaft and PTO input shaft, eliminating the need for various costly rear transmissions and streamlining production .

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to an embodiment shown in the drawings.

1 to 3 show a drive system of a tractor according to the present invention, in which 1 is a clutch housing and 2 is a clutch housing.
Is an intermediate transmission case fixed to the rear part of the clutch housing 1, and 3 is a rear transmission case fixed to the rear part of the intermediate transmission case 2 (hereinafter referred to as rear TM case). A flywheel 4, a main drive shaft 5, a clutch device 6 mounted on the flywheel 4, a clutch release hub 7, a hydrostatic transmission (hereinafter referred to as HST) 8 mounted on the front surface of the intermediate transmission case 2, and the like are housed. The main drive shaft 5 is connected to the input shaft 9 of the HST 8 via a shaft joint 45 described later. HST8 PTO output shaft 10 in the intermediate transmission case 2
And main output shaft 11 and PTO input shaft 12 in the rear TM case 3,
The respective shaft ends of the main input shaft 13 and the pinion shaft 14 are extended.
And PTO output shaft 10 of HST8 and PTO input shaft of rear TM case 3
12 are connected through a one-way clutch 15 with their shafts aligned, and the main output shaft 11 of the HST 8 and the main input shaft 13 of the rear TM case 3 are connected with misaligned connection parts as shown in FIGS. 2 and 3. Gears are connected to each other via an idle shaft 17 which constitutes 16.

That is, the gear 18 of the main output shaft 11 is appropriately decelerated inside the HST 8.
Is meshed with one gear 19 of the double integrated gears 19, 20 that are loosely fitted on the idle shaft 17, the other gear 20 is meshed with the gear 21 of the main input shaft 13 of the rear TM case 3, and the main output of the HST8 Axis 11
Is transmitted to the main input shaft 13 of the rear TM case 3 with different shaft cores.

Drive transmission gears 22, 23, 24 are provided on the main input shaft 13 of the rear TM case 3.
Is supported, and the rotation is selectively transmitted to the driven transmission gears 25, 26, 27 provided on the pinion shaft 14 from which the rotation is sub-shifted, and the bevel pinion 28 of the pinion shaft 14 drives the differential bevel gear 29, From this, the rear axle is driven through the final reduction gear. Further, the gear 30 of the pinion shaft 14 drives the sliding gear 33 of the front wheel drive shaft 32 via the idle gear 31 which is loosely fitted to the main input shaft 13, and the front wheel drive shaft 32 drives the front wheels during four-wheel drive. Switching between four-wheel drive and two-wheel drive is performed by sliding the sliding gear 33. Reference numeral 34 is a PTO shaft which is gear-connected to the PTO input shaft 12 and driven.

Predetermined rear part TM with a constant distance between the main input shaft 13 and the PTO input shaft 12
In addition, various HSTs with different intervals between the main output shaft 11 and the PTO output shaft 10
When 8 are combined, the position of the idle shaft 17 of the misaligned connecting portion 16 formed in the intermediate transmission case 2, the main output shaft 11 of the HST8, the idle shaft 17, and the main input shaft 13 of the rear TM case 3 are gear-connected. It is possible to combine various HSTs having different outputs with a predetermined rear part TM simply by changing each gear, and it becomes unnecessary to prepare various complicated and expensive rear part TMs.

4 to 6 show details of the clutch device 6, in which a clutch disc 35 splined to the main drive shaft 5 is pressed against a diaphragm spring type pressure plate 36 fixed to the flywheel 4. It is pressed against the flywheel 4 and the rotation of the flywheel 4, that is, the engine is transmitted to the main drive shaft 5. It is the clutch release hub 7 that acts on the pressure plate 36 to engage and disengage the clutch. The clutch release hub 7 is formed into a cylindrical shape that penetrates the main drive shaft 5 and is slidably fitted into a sleeve 37 provided in the clutch housing 1. The release bearing 38 that comes into contact with and separates from the pressure plate 36 is attached to the tip,
The rear end is formed into an oval shape by cutting a cylindrical shape with two parallel surfaces 39.
A bow-shaped cross section of the front part of the parallel two surfaces 39 serves as a passive portion 41 at the working end of the fork 40, and a projection 42 is formed on the rear part of the parallel two surfaces 39 for contacting the back surface of the working end of the fork 40.

The clutch release hub 7 is made of cast metal, and only the outer peripheral surface which slides on the inner surface of the sleeve 37 and the mounting portion of the release bearing 38 are machine-finished. The parallel two surfaces 39 and the passive portion 41 of the fork 40 are machined.
And the protrusion 42 leaves a chilled casting surface,
The wear due to contact with the fork 40 is suppressed as much as possible.

The fork 40 is rotatably supported by the fork shaft 43, and when the clutch pedal (not shown) is depressed, the working end of the fork 40 tilts forward to push the fork passive portion 41 of the clutch release hub 7 forward, and along with this, the release bearing at the tip. When 38 presses the central portion of the pressure plate 36, the outer peripheral portion of the pressure plate 36 bends backward, releasing the pressure contact of the clutch disc 35 with the four faces of the flywheel, and the clutch is disengaged.

The release bearing 38 prevents sliding when the clutch release hub 7, which is a non-rotating part, presses the rotating pressure plate 36, but the pressure plate 36 is still attached to the clutch release hub 7 when pressed.
Co-rotation occurs with. This rotational force is blocked by the engagement of the fork 40 with the parallel two surfaces 39 at the rear of the clutch release hub 7.

That is, in the conventional clutch release hub that slides on the outer circumference of the bush fitted on the main drive shaft, the bush wears due to the unbalanced load of the forks and the grease running between the bush and the main drive shaft, and the clutch is normally operated. In the conventional clutch release hub, which is fitted in and supported by a sleeve provided in the clutch housing and is slid, a stop bolt is used to prevent co-rotation with the clutch disc. However, the clutch device does not directly support the clutch release hub on the main drive shaft that rotates at high speed. There is no hindrance such as the bush being worn and the clutch not working properly.The co-rotation of the clutch release hub is Blocked by engagement of the line 2 side and the fork,
In addition, since the engagement surface with the fork is a chilled casting surface, the structure is simple, wear is small, and the cost of the clutch device can be reduced.

The connection between the main drive shaft 5 and the input shaft 9 of the HST 8 is performed via a cylindrical shaft joint 45 welded to the end of the main drive shaft 5. The details of the shaft coupling 45 are, as shown in FIGS. 7 and 8, an inner peripheral spline 47 of the shaft hole 46, a conical grease reservoir 48 on the clutch side of the shaft hole 46, and an inner peripheral O-ring groove 49 on the HST side. A diametrical pin hole 50 is formed in the middle portion, and a snap ring groove 51 is formed in an outer peripheral portion passing through the pin hole 50.

On the other hand, the input shaft 9 of the HST 8 is provided with an outer peripheral spline 52 that engages with the inner peripheral spline 47 of the shaft joint 45 and a pin hole 53 that matches the pin hole 50 of the shaft joint 45 on the outer periphery.

The main drive shaft 5 and the input shaft 9 of the HST 8 are assembled by filling the conical grease reservoir 48 of the shaft coupling 45 with grease, and at the inner and outer splines 47, 52 of the shaft coupling 45 and the HST input shaft 9. Grease is also applied to the inner circumference of the shaft coupling 45 and the O-ring groove 49.
The O-ring 54 is inserted into the shaft joint 45, the HST input shaft 9 is inserted into the shaft hole 46 of the shaft coupling 45, the pin 55 is inserted into both pin holes 50 and 53, and the snap ring 56 is fitted into the snap ring groove 51. Prevent pin 55 from coming off.

In other words, conventionally, the main drive shaft was connected to the input shaft of the HST or the input shaft of the mechanical transmission only by applying grease to the joint connecting portion, so the grease was scattered by the rotational centrifugal force of the shaft and after long-term operation. There was no lubrication between the splines of the joint connecting part, causing abnormal wear of the splines. However, according to the above-mentioned connecting part structure, the O-ring prevents grease from scattering and the grease is consumed due to heat generation. The grease is constantly replenished to the spline part from the conical grease reservoir by the rotating centrifugal force of the shaft, and the lubrication state is maintained without running out of grease for a long time and the service life of the shaft coupling part is enhanced.

9 to 12 show a drawbar housing device for housing the drawbar when not in use.

In a tractor without an intermediate PTO, when the drawbar is not used, it can be stored in the lower part of the machine by reversing the drawbar and fixing the base end to the drawbar bracket as shown by the chain double-dashed line in Fig. 12. , For a tractor equipped with an intermediate PTO, the intermediate PTO shaft cover was protruding below the rear transmission, and the above storage method was not possible, so there was no storage for the drawbars. For this reason the intermediate PTO
In the tractor provided with, when the drawbar is not used, it is removed and stored separately, which causes inconvenience such as being hard to find or lost during use. This drawbar storage device solves the above-mentioned inconvenience.

In the figure, 60 is a tractor with an intermediate PTO, 61 is a rear transmission, and 62 is a rear transmission.
An intermediate PTO case provided at the bottom of 61, 63 is a drawbar, and when used, the drawbar 63 is fixed to the drawbar bracket 64 at the rear of the intermediate PTO case 62 with its base end pinned with a snap pin 66. .

The drawbar bracket 64 is fastened with the front mounting plate 67 together with the central bracket 69 of the lower link shaft 68 to the intermediate PTO case 62 with bolts 70, and the rear mounting plate 71 is bolted to the left and right brackets 72 of the lower link shaft 68. It is fixed at 73.

74 and 75 are drawbar pockets for storing drawbars, the front drawbar pocket 74 is the brake cover 76 on the side of the rear transmission 61, and the rear drawbar pocket 75 is the bolt 78 on the plate 78 welded to the safety frame 77.
It is fixed at 9,80.

When the drawbar 63 is not used, remove the pin 65 and drawbar 63
Is removed from the drawbar bracket 64, and the pin 65 inserted into the front and rear drawbar pockets 74, 75 is inserted into the hole of the rear drawbar pocket 75 and the connecting pin hole 81 of the drawbar, and the snap pin 66 is used to prevent it from being stored.

Thus, the drawbar 63 can be stored securely when not in use,
The trouble of searching and the inconvenience of loss are eliminated.

FIGS. 14 and 15 show an example of the storage place when the drawbar is not used, provided in a place different from the above.The storage place is provided on the back of the center cover 83 between the fenders 82, 82 on both sides of the tractor. ing.

That is, the center cover 83 has a drawbar storage plate 84.
Are fixed by bolts 85, and a pair of pins 86 are planted in the drawbar storage plate 84 at predetermined intervals. Drawbar
When the 63 'is not in use, the hole provided in the drawbar 63' is inserted into the pin 86 of the drawbar storage plate 84 to snap the pin.
The drawbar 63 'can be stored if it is stopped at 66'. This storage area is the closest and convenient to the place where the drawbar is used.

FIGS. 16 to 19 show a key switch operation unit of a tractor which can protect the key hole from invasion of rainwater and dust and has an easy-to-see display plate.

As shown in FIG. 9 described above, a key switch operating section 92 is provided on a cover 91 below the panel 90 of the tractor 60. Conventionally, there is no particular shield in this key switch operation unit 92, so that the key hole is covered with a cap, the cap is inserted and the key is inserted at the time of operation, and the key is removed and the cap is put on at the end of the operation, and rainwater is discharged from the key hole. This prevents the key switch from breaking down due to dust and dirt. This operation is quite troublesome, and sometimes the user forgets to put on the cap and rainwater or dust intrudes, causing a contact failure on the key switch and preventing the engine from starting.

Further, since the key switch operating unit 92 is provided on the cover surface which is almost vertical, it is difficult for the operator to see even if the display plate is attached to this cover surface.

As shown in FIGS. 16 and 17, this key switch operating section is provided with an arc-shaped eaves plate 96 on the upper part of a key switch 95 composed of a key switch body 93 and a cap 94, and an eaves plate 96.
Display panel 98 that displays the ON / OFF position of key 97 on the top surface of
Is attached. To assemble these, as shown in FIG. 18, the key switch main body 93 is inserted into the key switch mounting hole 99 provided in the cover 91 from the back side of the cover 91, the cap 94 is tightened from the front side, and the key switch 95 is attached. Eaves board
96 is, for example, an angle material bent in an arc shape and a key switch
Fix it slightly above 95 with spot welding or rivets. Then, the display plate 97 is attached to the upper surface of the eaves plate 96.

Note that the eaves plate 96 may not be fixed to the cover 91, but may be attached together with the key switch main body 93 together with the cap 94 as shown in FIG. 19, so that water, mud, etc. are scattered. The eaves plate 96 can be rotated in the direction in which it comes in, and when muddy water is scattered from below, for example, when scraping work, the eaves plate 96 is directed downward to prevent the muddy water from entering the key hole. can do.

Further, since the display plate 98 is attached to the upper surface of the eaves plate 96, it is easy to visually recognize it during a driving operation.

20 and 21 show a tool box utilizing the internal space of the clutch housing.

This tool box focuses on the fact that the clutch housing of an HST type tractor extends backwards and is long, and that the main drive shaft only penetrates inside, leaving room for internal space. In the figure, 1'is a clutch housing, 5'is a main drive shaft, and 9'is an HST input shaft. 20 shows a tool housing in which an opening 101 is provided on the upper surface of the clutch housing 1'and a box-shaped plate 102 is fixed inside, and a lid 104 which can be opened and closed by a knob 103 is provided in the opening 101. It is set as 100.

21 shows a tool box 100 in which a box-shaped recess 105 is integrally formed on the upper surface plate of the clutch housing 1'and a lid plate 104 which can be opened and closed by a knob 103 is provided on the upper part thereof.

In the past, small tractors had little space and it was difficult to install the tool box.However, the HST drive tractor uses the internal space of the clutch housing to obtain a tool box with a comparatively large capacity. It can be done and is less obtrusive than an external tool box, and it also serves as a reinforcement for the clutch housing.

As mentioned above, the present invention has an engine output shaft and a rear TM.
In the drive system structure of the tractor in which the HST is interposed between the main input shaft of the rear TM and the PTO input shaft having a predetermined shaft gap,
An intermediate transmission case with internal misalignment connecting parts respectively connected to the TO output shaft is interposed between the clutch housing and the rear part TM, and the HST is mounted on the front surface of the intermediate transmission case and the clutch is attached. Since it is housed in the housing, noise generated by HST is reduced, and the HST side of the misaligned connection part configured in the intermediate transmission case is aligned with the main output shaft of the HST and the PTO output shaft interval. With this, it is possible to combine various HSTs with different outputs to the rear TM with a fixed interval between the main input shaft and the PTO input shaft, and it is not necessary to prepare various expensive rear TMs, which can streamline production. .

[Brief description of drawings]

1 to 3 show an embodiment of the present invention, FIG. 1 is a side sectional view of a drive system according to the present invention, FIG. 2 is a developed side sectional view of a misaligned connecting portion, and FIG. FIG. 3 is a sectional view taken along the line III-III in FIG. 1. 4 to 6 show the details of the clutch device.
FIG. 4 is a side sectional view of the device, FIG. 5 is a rear view of the device, and FIG. 6 is a perspective view of a clutch release hub of the device. 7 and 8 are views showing the structure of a shaft coupling that connects the main drive shaft and the input shaft of the hydrostatic transmission. FIG. 7 is a side sectional view before the connection, and FIG. 8 shows the connected state. It is a sectional side view. FIGS. 9 to 13 show a drawbar storage device. FIG. 9 is a side view of an entire tractor adopting this storage device, and FIG. 10 is a side view of a main part of the tractor when the drawbar is used. FIG. 11 is a rear view of the main part of FIG. 10, and FIG.
FIG. 13 is a bottom view of the main part of the figure, and FIG. 13 is a plan view of the rear pocket attachment part of the drawbar. FIGS. 14 and 15 show a drawbar storage device in which the storage location is different from that of the front device. FIG. 14 is a side view thereof, and FIG. 15 is a rear view thereof. FIGS. 16 to 19 show the key switch operating portion of the improved tractor. FIG. 16 is a side view thereof, FIG. 17 is a front view thereof, and FIG. 18 is an eaves-fixing type assembly perspective. Figure, No. 19
The figure is a perspective view of the eaves-rotating type assembly. 20 and 21 show a tool box provided in a clutch housing of a tractor, FIG. 20 is a side sectional view of a structural example thereof, and FIG. 21 is a side sectional view of a structural example different from FIG. . 1 ... Clutch housing, 2 ... Intermediate transmission case, 3
…… Rear transmission case, 8 …… Hydrostatic transmission, 10 …… Hydrostatic transmission PT
O output shaft, 11 ... Main output shaft of hydrostatic transmission, 12 ... PTO input shaft of rear transmission, 13 ...
… Main transmission input shaft for rear transmission, 16 …… Mixed core connection.

Claims (1)

[Scope of utility model registration request] 1. In a drive system structure of a tractor in which a hydrostatic transmission is interposed between an output shaft of an engine and a rear transmission, a main input shaft of the rear transmission and a PTO input shaft having a predetermined shaft interval are provided. An intermediate transmission case internally configured with a misaligned connecting part that connects to the main output shaft and PTO output shaft of various hydrostatic transmissions with different intervals from both shafts is interposed between the clutch housing and the rear transmission case, A drive system structure in a tractor having a hydrostatic transmission, characterized in that the hydrostatic transmission is mounted on a front surface of the intermediate transmission case and housed in a clutch housing.