Speed change control device in working vehicles

Details Speed change control device in working vehicles Speed change control device in working vehicles

2000-03-03

2001-08-07

Bonck, Rodney H. (Department: 3681)

192 clutches and power-stop control

Clutches

Operators

C192S083000

Reexamination Certificate

active

06269927

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to a speed change control device having a novel valve mechanism for fluid-operated clutches in a working vehicle in which the vehicle running speed is changed by the operation of plural fluid-operated clutches.
BACKGROUND OF THE INVENTION
In a working vehicle in which the vehicle running speed is changed by the selective operation of plural fluid-operated clutches, it is already known from, for example, Japanese Patent No. 2,668,359 that plural direction control valves for controlling the supply of operating fluid individually to the plural fluid-operated clutches, particularly plural electromagnetic proportional direction control valves which permit the control of fluid pressure applied to the plural fluid-operated clutches, are employed for controlling the vehicle speed and that plural pressure sensors for sensing fluid pressure applied to the individual fluid-operated clutches electrically are employed for preventing abnormal double engagements of the fluid-operated clutches. However, there has not been provided yet a speed change control device which has such plural direction control valves and such plural pressure sensors in close proximity to the plural fluid-operated clutches in a compact manner and for an easy inspection and maintenance.
Accordingly, a primary object of the present invention is to provide a novel speed change control device in which plural direction control valves and plural pressure sensors are provided in close proximity to plural fluid-operated clutches in a compact manner and for an easy inspection and maintenance.
SUMMARY OF THE INVENTION
The present invention relates to a speed change control device in a working vehicle in which the vehicle running speed is changed by the selective operation of plural fluid-operated clutches. According to the present invention, a valve casing (
55
) is mounted on an outer side surface of a vehicle body (
2
) which includes the plural fluid-operated clutches. The valve casing has plural direction control valves (
46
H,
46
L,
46
A,
46
B,
46
C) for controlling the supply of operating fluid individually to the plural fluid-operated clutches and plural pressure sensors (
47
H,
47
L,
47
A,
47
B,
47
C) for respectively sensing fluid pressure applied to the plural fluid-operated clutches. The plural direction control valves (
46
H,
46
L,
46
A,
46
B.
46
C) are secured to the valve casing (
55
) from one of upper and lower surfaces of the casing, and the plural pressure sensors (
47
H,
47
L,
47
A,
47
B,
47
C) are secured to the valve casing (
55
) from the other of the upper and lower surfaces of the casing. Preferably, the plural direction control valves (
46
H,
46
L,
46
A,
46
B,
46
C) and the plural pressure sensors (
47
H,
47
L,
47
A,
47
B,
47
C) are arranged respectively in parallel in a longitudinal direction of the vehicle body (
2
).
Because the plural control valves and the plural pressure sensors are secured, according to the present invention, to the valve casing mounted on an outer side surface of the vehicle body which includes the plural fluid-operated clutches, the plural control valves and pressure sensors are in close proximity to the plural fluid-operated clutches, so that the supply of operating fluid to the fluid-operated clutches is controlled quickly and fluid pressure applied to the fluid-operated clutches are sensed precisely. The control valves and pressure sensors secured to the valve casing mounted on an outer side surface of the vehicle body permit an easy access to these valves and sensors for inspection and maintenance thereof. Because the plural control valves are secured to the valve casing from one of upper and lower surfaces thereof and the plural pressure sensors are secured to the valve casing from the other of the upper and lower surfaces thereof, the plural control valves and pressure sensors are arranged in a compact manner. When the plural direction control valves and the plural pressure sensors are arranged respectively in parallel in a longitudinal direction of the vehicle body according to a preferred embodiment of the present invention, the plural control valves and pressure sensors are arranged without enlarging width of the valve casing even when the fluid-operated clutches in the vehicle body are increased in number. Recently, a fuel tank for storing fuel for engine is often provided at an outer side of the vehicle body, and in such a case, too, the speed change control device can be provided in an inner side of such a fuel tank in a compact manner.
According to a preferred embodiment of the present invention, the valve casing (
55
) is composed of an outer plate member (
57
) to which the plural direction control valves (
46
H,
46
L,
46
A,
46
B,
46
C) and the plural pressure sensors (
47
H,
47
L,
47
A,
47
B,
47
C) are secured, an inner plate member (
58
) comprising plural output ports (
60
H,
60
L,
60
A,
60
B,
60
C) which are connected respectively to the plural fluid-operated clutches (
40
H,
40
L,
43
A,
43
B,
43
C), and a separator member (
59
) which is interposed between the outer and inner plate members (
57
,
58
) and which has plural fluid passage bores for connecting fluid passages in the outer plate member (
57
) and fluid passages in the inner plate member (
58
).
A number of fluid passages and ports are formed in the valve casing in correspondence with the plural control valves and pressure sensors, and when such fluid passages and ports are to be formed in a one-piece valve casing the shaping of such fluid passages and ports will be very complicated so that they are very difficult to machine. Contrary, fluid passages in the outer and inner plate members can be formed as grooves in an inner side surface of the outer plate member, at which surface the outer plate member is in abutment on the separator member, and in an outer side surface of the inner plate member, at which surface the inner plate member is in abutment on the separator member, and such grooves in the outer and inner plate members can be communicated through fluid passage bores in the separator member. Ports can be formed in the outer plate member and in the inner plate member such that they open into the grooves in the outer plate member and in the inner plate member at suitable positions of the grooves. Thus, the fluid passages and ports can be formed very easily.


REFERENCES:
patent: 3874255 (1975-04-01), Minami
patent: 4262554 (1981-04-01), Ahlen et al.
patent: 5599247 (1997-02-01), Matsufuji
patent: 5669479 (1997-09-01), Matsufuji
patent: 0 419 984 (1991-04-01), None
patent: 2668359 (1997-10-01), None

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