U.S. patent application number 11/683251 was filed with the patent office on 2007-11-29 for pump unit and working vehicle.
Invention is credited to Ryota OHASHI, Hironori Sumomozawa.
Application Number | 20070272469 11/683251 |
Document ID | / |
Family ID | 28043863 |
Filed Date | 2007-11-29 |
United States Patent
Application |
20070272469 |
Kind Code |
A1 |
OHASHI; Ryota ; et
al. |
November 29, 2007 |
Pump Unit and Working Vehicle
Abstract
A pump unit for supply and discharge of hydraulic fluid into and
from an actuator upon receiving driving power from a driving source
is provided, in which said actuator is fluidly connected to said
pump unit via a hydraulic circuit. The pump unit includes an input
member operatively connected to the driving source, a first
hydraulic pump body operatively connected to the input member, a
pump case for accommodating the first hydraulic pump body and
forming a hydraulic fluid sump, and a PTO unit accommodated within
the pump case. The PTO unit includes a PTO shaft supported by the
pump case so as to have an end extending outward from the pump
case, and a clutch mechanism for selectively enabling and disabling
transmission of driving power from the input member to the PTO
shaft.
Inventors: |
OHASHI; Ryota; (Hyogo,
JP) ; Sumomozawa; Hironori; (Hyogo, JP) |
Correspondence
Address: |
STERNE, KESSLER, GOLDSTEIN & FOX P.L.L.C.
1100 NEW YORK AVENUE, N.W.
WASHINGTON
DC
20005
US
|
Family ID: |
28043863 |
Appl. No.: |
11/683251 |
Filed: |
March 7, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11169015 |
Jun 29, 2005 |
7237643 |
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11683251 |
Mar 7, 2007 |
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10403020 |
Apr 1, 2003 |
6988580 |
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11169015 |
Jun 29, 2005 |
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Current U.S.
Class: |
180/306 |
Current CPC
Class: |
F15B 2211/40507
20130101; F15B 11/17 20130101; F15B 2211/423 20130101; F15B
2211/20546 20130101; B60K 17/105 20130101; F15B 2211/7142 20130101;
F15B 2211/214 20130101; F04B 1/22 20130101; F15B 2211/7058
20130101; F15B 2211/20561 20130101; B60K 17/10 20130101; B60K 25/00
20130101; F15B 2211/41536 20130101; F15B 2211/40584 20130101; F15B
2211/27 20130101; B60K 25/02 20130101; B60Y 2200/223 20130101; F15B
2211/20576 20130101; B60K 17/28 20130101; B60K 25/06 20130101; F15B
2211/40515 20130101; F15B 2211/473 20130101; A01D 34/6806
20130101 |
Class at
Publication: |
180/306 |
International
Class: |
B60K 17/00 20060101
B60K017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 3, 2002 |
JP |
2002-101100 |
Apr 15, 2002 |
JP |
2002-112128 |
Claims
1.-24. (canceled)
25. A pump unit for supplying and suctioning hydraulic fluid into
and from a motor unit upon receiving driving power from a driving
source, the motor unit having a motor shaft for outputting a
mechanical rotational power toward a driving wheel and a hydraulic
motor body for rotating the motor shaft, and being accommodated
outside the pump unit so as to be located away from the pump unit
and fluidly connected to the pump unit via a hydraulic circuit,
comprising: an input member operatively connected to the driving
source; a first hydraulic pump body operatively connected to the
input member, the first hydraulic pump body being of a variable
displacement type so that a mechanical rotational power with
variable speed can be outputted through the motor shaft; a pump
case for accommodating the first hydraulic pump body and forming a
hydraulic fluid sump; fluid connection ports disposed on an outside
surface of the pump case for fluidly connecting the first hydraulic
pump body with the hydraulic motor body of the motor unit; and a
PTO unit accommodated within the pump case the PTO unit comprising:
a PTO shaft supported by the pump case so as to have an end
extending outward from the pump case; and a clutch mechanism for
selectively engaging or disengaging power transmission from the
input member to the PTO shaft.
26. A pump unit according to claim 25, wherein the pump case has an
opening, wherein the pump case further comprises a center section
connected to a pump case body so as to close the opening, while
supporting the first hydraulic pump body on one of opposite sides
thereof, wherein a part of the hydraulic circuit is formed in the
center section.
27. A pump unit according to claim 26, further comprising a charge
pump unit for sucking hydraulic fluid from the hydraulic fluid sump
and discharging the same to the hydraulic circuit, wherein the
charge pump unit is operatively connected to the input member and
supported on the other of the opposite sides of the center
section.
28. A pump unit according to claim 27, wherein the PTO unit further
comprises a brake mechanism for releasing and applying braking
force away from and to the PTO shaft in association with the
operation of the clutch mechanism to engage and disengage power
transmission from the input member to the PTO shaft, wherein the
brake mechanism and the clutch mechanism are operated by hydraulic
fluid discharged by the charge pump unit.
29. A pump unit according to claim 25, wherein the PTO unit further
comprises a brake mechanism for releasing and applying braking
force away from and to the PTO shaft in association with the
operation of the clutch mechanism to engage and disengage power
transmission from the input member to the PTO shaft.
30. A pump unit according to claim 25, further comprising an input
shaft acting as the input member, and a first pump shaft that is
operatively connected to the input shaft and drives the first
hydraulic pump body.
31. A pump unit according to claim 30, wherein the PTO shaft is
arranged coaxially with the input shaft.
32. A pump unit according to claim 30, wherein the PTO shaft has an
axis, which is located at the same position as an axis of the input
shaft in a vehicle width direction, and is arranged orthogonal to
the axis of the input shaft.
33. A pump unit according to claim 25, further comprising a first
pump shaft that acts as the input member and drives the first
hydraulic pump body.
34. A pump unit according to claim 33, wherein the PTO shaft is
arranged substantially parallel to the first pump shaft.
35. A pump unit according to claim 33, wherein the PTO shaft is
arranged substantially orthogonal to the first pump shaft.
36. A pump unit for supplying and suctioning hydraulic fluid into
and from first and second motor units upon receiving driving power
from a driving source, each of the first and second motor units
having a motor shaft for outputting a mechanical rotational power
toward a corresponding driving wheel and a hydraulic motor body for
rotating the motor shaft, and being accommodated outside the pump
unit so as to be located away from the pump unit and fluidly
connected to the pump unit via a hydraulic circuit, comprising: an
input member operatively connected to the driving source; a first
hydraulic pump body operatively connected to the input member, the
first hydraulic pump body being of a variable displacement type so
that a mechanical rotational power with variable speed can be
outputted through the motor shaft of the first motor unit; a second
hydraulic pump body operatively connected to the input shaft, the
second hydraulic pump body being of a variable displacement type so
that a mechanical rotational power with variable speed can be
outputted through the motor shaft of the second motor unit; a pump
case for accommodating the first and second hydraulic pump bodies
and forming a hydraulic fluid sump, the pump case having an opening
through which the first and second hydraulic pump bodies can pass,
the pump case further comprising a center section connected to a
pump case body so as to close the opening while supporting the
first and second hydraulic pump bodies, the center section forming
therein a part of the hydraulic circuit is formed in the center
section; first fluid connection ports being arranged on an outside
surface of the center section for fluidly connecting the first
hydraulic pump body with the hydraulic motor body of the first
motor unit; second fluid connection ports for fluidly connecting
the second hydraulic pump body with the hydraulic motor body of the
second motor unit, the second fluid connection ports being arranged
at the same side of the center section as the first fluid
connection ports; and a PTO unit accommodated within the pump case
the PTO unit comprising: a PTO shaft supported by the pump case so
as to have an end extending outward from the pump case; and a
clutch mechanism for selectively engaging or disengaging power
transmission from the input member to the PTO shaft.
37. A pump unit that receives driving power from a driving source
and that supplies and suctions hydraulic fluid into and from a pair
of right and left motor units for operatively and respectively
driving a pair of driving wheels, comprising: an input member
operatively connected to the driving source; a first hydraulic pump
body that is operatively connected to the input member and that is
of a variable displacement type; a pump case for accommodating the
first hydraulic pump body and forming a hydraulic fluid sump, the
pump case being provided with fluid connection ports through which
the first hydraulic pump body supplies and suctions hydraulic fluid
on its outside surface; and a PTO unit that is accommodated within
the pump case, the PTO unit having a PTO shaft supported by the
pump case so as to have a first end extending outward from the pump
case, and a clutch mechanism for selectively engaging or
disengaging power transmission from the input member to the PTO
shaft, wherein the PTO shaft mechanically and operatively drives a
working machine, and wherein the hydraulic fluid that the first
pump body supplies and suctions trough the connection ports
hydraulically drives the motor units disposed away from the pump
unit.
38. A pump unit that receives driving power from a driving source
and that supplies and suctions hydraulic fluid into and from a pair
of right and left motor units for operatively and respectively
driving a pair of driving wheels, comprising: an input member
operatively connected to the driving source; a first hydraulic pump
body that is operatively connected to the input member and that is
of a variable displacement type; a second hydraulic pump body that
is operatively connected to the input member and that is of a
variable displacement type, the first and second hydraulic pumps
being configured to be capable of controlling their volumes
independently to each other; a pump case for accommodating the
first and second hydraulic pump bodies and forming a hydraulic
fluid sump, the pump case being provided with first fluid
connection ports through which the first hydraulic pump body
supplies and suctions hydraulic fluid and second fluid connection
ports through which the second hydraulic pump body supplies and
suctions hydraulic fluid on its outside surface; and a PTO unit
accommodated within the pump case, the PTO unit having a PTO shaft
supported by the pump case so as to have a first end extending
outward from the pump case, and a clutch mechanism for selectively
engaging or disengaging power transmission from the input member to
the PTO shaft; wherein the PTO shaft mechanically and operatively
driving a working machine, and the hydraulic fluid that the first
pump body supplies and suctions trough the first connection ports
hydraulically drives one of the motor units and the hydraulic fluid
that the second pump body supplies and suctions through the second
connection ports hydraulically drives the other of the motor units,
the motor units being disposed away from the pump unit.
39. A pump unit disposed away from right and left wheel motors and
supplying hydraulic fluid to the wheel motors through conduits in
order to hydraulically drive the wheel motors, comprising: first
and second hydraulic pump bodies respectively and independently
supplying hydraulic fluid to the right and left wheel motors; a
pump case having one or more openings for inserting the first and
second hydraulic pump bodies into the pump case; one or more center
sections closing the one or more openings while supporting the
first and second hydraulic pump bodies, the one or more center
sections being provided with plurality of fluid connection ports
for fluidly connecting the first and second hydraulic pumps to the
right and left wheel motors; a first pump shaft driving the first
pump body; a second pump shaft driving the second pump body; a PTO
unit including a clutch mechanism that is accommodated within the
pump case, and a PTO shaft that is operatively connected to a
driven-side of the clutch mechanism and has a first end extending
outward from the pump case; and an input shaft that has a first end
extending outward from the pump case to receive driving power, and
a second end constantly and operatively connected to the first and
second pump shafts and operatively connected the PTO shaft through
the clutch mechanism.
40. A pump unit according to claim 39, wherein the PTO shaft is
arranged coaxially with the input shaft.
41. A pump unit according to claim 39, wherein the PTO shaft is
arranged orthogonally to the first and second pump shafts.
42. A pump unit according to claim 39, wherein the pump case has
the one opening, and the pump unit has the one center section
closing the one opening while supporting both of the first and
second hydraulic pump bodies.
43. A pump unit according to claim 39, wherein the pump case has a
partition wall that divides the inner space of the pump case into a
space for accommodating the first and second pump bodies and a
space for accommodating the PTO unit.
44. A pump unit according to claim 39, wherein the clutch mechanism
includes friction plates that engages power transmission from the
input shaft to the PTO shaft when the hydraulic pressure is applied
and disengages the power transmission when the hydraulic pressure
is not applied, the pump unit further comprises a charge pump
acting as a hydraulic pressure source, and the charge pump is
supported by the pump case so as to be operatively driven by the
input shaft.
45. A pump unit according to claim 44, wherein the PTO unit further
comprises a brake mechanism for applying braking force to the PTO
shaft when the clutch mechanism disengages power transmission from
the input shaft to the PTO shaft.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 11/169,015, filed Jun. 29, 2005, which is a continuation of
U.S. application Ser. No. 10/403,020, filed Apr. 1, 2003, the
entire disclosures of which are incorporated in their entirety
herein by reference thereto. This application claims priority from
Japanese Patent Application Nos. 2002-101100 and 2002-112128, which
are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a pump unit that is
operatively connected to a driving source and fluidly connected to
an actuator via a hydraulic circuit so as to be capable of
outputting driving power with variable speed through the
actuator.
[0004] 2. Background Art
[0005] The hydraulic pump unit is used in various fields of
applications, one of which is directed to a cooperative operation
with the actuator which is arranged away from the hydraulic pump
unit. In this application, the hydraulic pump unit and the actuator
are connected to each other via a hydraulic circuit so as to
together constitute a main transmission path for receiving driving
power from a driving source and outputting the same with variable
speed.
[0006] In some applications, a power transmission structure
equipped with the hydraulic pump unit requires a sub transmission
path in addition to the main transmission path. Such a requirement
exists, for example, in a lawn mower, in which power from a common
driving source is divided and output into a running-power
transmission path and a PTO power transmission path.
[0007] Now, the description will be made for the arrangement where
a hydraulic motor unit is used as the actuator.
[0008] U.S. Pat. Nos. 4,395,865 (hereinafter referred to '865
patent), 5,809,756 (hereinafter referred to '756 patent) and other
prior art references disclose a lawn mower that includes a PTO
power transmission path for receiving power from an engine and
outputting the same to a mower as well as a running power
transmission path that is made up of a hydraulic pump unit
operatively connected to the engine and a hydraulic motor unit
located away from the hydraulic pump unit so as to drive driving
wheels.
[0009] Specifically, the lawn mower in the '865 patent provides the
engine as a common driving source with first and second output
shafts, which are respectively and operatively connected to the
hydraulic pump unit and a mower unit. That is, in the lawn mower of
the '865 patent, the running power transmission path is entirely
separated from the PTO power transmission path. However, this
entire separation of the running power transmission path and the
PTO power transmission path necessitates a large number of parts
for separately forming these transmission paths and a large space
for accommodating these separate transmission paths. Also, the
power transmission structure with two separate power transmission
paths requires independent control for enabling and disabling the
transmission of power in each transmission path. In order to
achieve this control, in the lawn mower of the '865 patent, an
electromagnetic clutch for enabling and disabling the transmission
of power is placed in each transmission path. This electromagnetic
clutch has however poor durability, and therefore may result in
loss in reliability to each transmission path.
[0010] On the other hand, the lawn mower of the '756 patent
provides the engine with a common output shaft, on which a driving
pulley and a mower pulley are supported, so that power can be
divided into the running power transmission path and the PTO power
transmission shaft through this common output shaft. In order to
achieve this arrangement, the common output shaft must be
lengthened, which results in a larger load applied thereon. The
'756 patent is also silent as to how to enable and disable the
transmission of power in each transmission path.
[0011] The present invention has been conceived in consideration of
the above prior arts. Accordingly, it is an object of the present
invention to provide a pump unit that is operatively connected to a
driving source and fluidly connected to an actuator via a hydraulic
circuit so as to output driving power with variable speed through
the actuator, and has a simplified structure enabling dividing
driving power from the driving source into a sub transmission path
as well as into a main transmission path, which the pump unit
constitutes in cooperation with the actuator.
[0012] It is another object of the present invention to provide a
working vehicle having a simplified structure, which includes a PTO
power transmission path extending from a drive source to a working
unit for land treatment such as a mower unit (hereinafter simply
referred to as "working unit"), as well as a running power
transmission path that is made up of a hydraulic pump unit for
receiving driving power from a driving source, and a hydraulic
motor unit located away from the hydraulic pump unit and fluidly
connected thereto.
SUMMARY OF THE INVENTION
[0013] According to one aspect of the present invention, there is
provided a pump unit for supply and discharge of hydraulic fluid
into and from an actuator upon receiving driving power from a
driving source, in which the actuator is fluidly connected to the
pump unit via a hydraulic circuit. The pump unit includes an input
member operatively connected to the driving source, a first
hydraulic pump body operatively connected to the input member, a
pump case for accommodating the first hydraulic pump body and
forming a hydraulic fluid sump, and a PTO unit accommodated within
the pump case. The PTO unit includes a PTO shaft supported by the
pump case so as to have an end extending outward from the pump
case, and a clutch mechanism for selectively enabling and disabling
transmission of driving power from the input member to the PTO
shaft.
[0014] With the thus arranged pump unit, it is possible to easily
make up a reduced-size sub transmission path that can be controlled
independently of the main transmission path, while making up the
main transmission path in cooperation with the actuator fluidly
connected to the pump unit. Also, since the operation to enable and
disable the power transmission is performed by the clutch
mechanism, the sub transmission path can have an improved
durability.
[0015] Preferably, the pump case has an opening, and the pump unit
further includes a center section connected to the pump case so as
to close the opening, while supporting the first hydraulic pump
body on one of opposite sides thereof, in which the hydraulic
circuit is disposed in the center section.
[0016] The pump unit may further include a charge pump unit for
sucking hydraulic fluid from the hydraulic fluid sump and
discharging the same to the hydraulic circuit, in which the charge
pump unit is operatively connected to the input member and
supported on the opposite side of the center section.
[0017] With the thus arranged pump unit, the charge pump unit can
be used as a fluid supply source for supplying pressurized
hydraulic fluid to the hydraulic circuit, thereby achieving easy
supply of pressurized hydraulic fluid to the hydraulic circuit.
[0018] The pump unit may further include a second hydraulic pump
body operatively connected to the input member, in which the
opening of the pump case is adapted to enable the first and second
hydraulic pump bodies to pass therethrough, and the center section
is connected to the pump case so as to close the opening, while
supporting the first and second hydraulic pump bodies.
[0019] The PTO unit may further include a brake mechanism for
releasing and applying braking force away from and to the PTO shaft
in association with the operation of the clutch mechanism to enable
and disable the transmission of driving power from the input member
to the PTO shaft. With this arrangement, it is possible to
effectively prevent the PTO shaft from continuing to rotate by
inertia when the power transmission to the PTO shaft has been
disabled.
[0020] The PTO unit may further include a brake mechanism for
releasing and applying braking force away from and to the PTO shaft
in association with the operation of the clutch mechanism to enable
and disable the transmission of driving power from the input member
to the PTO shaft, in which the brake mechanism and the clutch
mechanism are of hydraulic type that is operated by hydraulic fluid
discharged by the charge pump unit. With this arrangement, the
charge pump unit can be used as a fluid supply source for supplying
pressurized hydraulic fluid to the hydraulic clutch mechanism and
the hydraulic brake mechanism, thereby achieving a simplified
structure of a hydraulic circuit of each of the hydraulic clutch
mechanism and the hydraulic brake mechanism.
[0021] The pump unit may further include an input shaft acting as
the input member, and a first pump shaft for driving the first
hydraulic pump body.
[0022] In the above pump unit, the PTO shaft may be arranged
coaxially with the input shaft.
[0023] With the thus arranged pump unit, the sub transmission path
from the driving source to the working unit can be formed
substantially in a linear fashion, thereby achieving a simplified
structure of the sub transmission path and occupation of less space
by the pump unit.
[0024] According to another aspect of the present invention, there
is provided a working vehicle that includes a vehicle frame, a
first pair of laterally disposed wheels supported by the vehicle
frame, a second pair of laterally disposed wheels supported by the
vehicle frame so as to be located away from the first pair of
laterally disposed wheels in a fore and aft direction of the
working vehicle, a working unit supported by the vehicle frame, a
driving source supported by the vehicle frame, first and second
motor units respectively and operatively connected to the first
pair of laterally disposed wheels, and a pump unit supported by the
vehicle frame so as to be operatively connected to the driving
source. The pump unit is arranged to supply and discharge hydraulic
fluid into and from each of the first and second motor units, and
take out driving power of the driving source and output the same as
driving power for the working unit. The pump unit includes an input
member operatively connected to the driving source, a first
hydraulic pump body operatively connected to the input member, a
pump case for accommodating the first hydraulic pump body, and a
PTO unit accommodated within the pump case. The PTO unit includes a
PTO shaft supported by the pump case so as to have an end extending
outward from the pump case, and a clutch mechanism for selectively
enabling and disabling transmission of driving power from the input
member to the PTO shaft.
[0025] With the thus arranged working vehicle, it is possible to
easily make up a reduced-size sub transmission path that can be
controlled independently of the main transmission path, while
making up the main transmission path in cooperation with the
actuator fluidly connected to the pump unit. Also, since the
operation to enable and disable the power transmission is performed
by the hydraulic clutch mechanism, the sub transmission path can
have an improved durability.
[0026] The working vehicle may further include a charge pump unit
that is operatively connected to the input member. With the thus
arranged working vehicle, the charge pump unit can be used as a
fluid supply source for supplying pressurized hydraulic fluid to
the hydraulic circuit, thereby achieving easy supply of pressurized
hydraulic fluid to the hydraulic circuit.
[0027] The pump unit may further include a second hydraulic pump
body operatively connected to the input member.
[0028] The PTO unit may further include a brake mechanism for
releasing and applying braking force away from and to the PTO shaft
in association with the operation of the clutch mechanism to enable
and disable the transmission of driving power from the input member
to the PTO shaft.
[0029] With the thus arranged working vehicle, it is possible to
effectively prevent the PTO shaft from continuing to rotate by
inertia when the power transmission to the PTO shaft has been
disabled.
[0030] The driving source may be supported on the vehicle frame in
vibration free manner, while the pump unit is fixedly supported on
the vehicle frame, and the driving source is operatively connected
to the input member via vibration-absorbing transmission means.
[0031] The driving source may be supported on the vehicle frame in
vibration free manner, while the pump unit is integrally connected
to the driving source.
[0032] The pump unit may further include an input shaft acting as
the input member, and a first pump shaft operatively connected to
the input shaft and arranged to drive the first hydraulic pump
body.
[0033] The PTO shaft may be arranged coaxially with the input
shaft. With this arrangement, the sub transmission path from the
driving source to the working unit can be formed substantially in a
linear fashion, thereby achieving a simplified structure of the sub
transmission path and occupation of less space by the pump
unit.
[0034] In the thus arranged working vehicle, the PTO shaft may have
an axis, which is located at the same position as an axis of the
input shaft in a vehicle width direction, and is arranged
substantially orthogonal to the axis of the input shaft.
[0035] The pump unit may further include a first pump shaft that
acts as the input member and is arranged to drive the first
hydraulic pump body. The first pump shaft may be arranged
substantially parallel to the PTO shaft. As an alternative thereto,
the first pump shaft may be arranged substantially orthogonal to
the PTO shaft.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] The above, and other objects, features and advantages of the
present invention will become apparent from the detailed
description thereof in conjunction with the accompanying drawings
wherein.
[0037] FIGS. 1A and 1B are respectively a side view and a plan view
of a lawn 1 mower, to which a pump unit of a first embodiment of
the present invention has been applied.
[0038] FIG. 2 is a hydraulic circuit diagram of the pump unit
according to the first embodiment.
[0039] FIG. 3 is a plan view in horizontal cross section of the
pump unit according to the first embodiment.
[0040] FIG. 4 is a side view in vertical cross section of the pump
unit of FIG. 3. FIG. 5 is a plan view of the pump unit having a
hydraulic brake mechanism of another embodiment with a part in
horizontal cross section. FIG. 6 is a plan view of the lawn mower,
to which the pump unit of a second embodiment has been applied.
[0041] FIG. 7 is a plan view in horizontal cross section of the
pump unit according to the second embodiment.
[0042] FIGS. 8A and 8B are a side view and a plan view of the lawn
mower, to which the pump unit of a third embodiment has been
applied.
[0043] FIG. 9 is a plan view in horizontal cross section of the
pump unit according to the third embodiment.
[0044] FIG. 10 is a side view in vertical cross section of the pump
unit according to the third embodiment.
[0045] FIG. 11 is a cross section taken along the line XI-XI in
FIG. 9.
[0046] FIG. 12 is a plan view of the lawn mower, to which the pump
unit according to a modified example of the third embodiment has
been applied.
[0047] FIG. 13 is a plan view in horizontal cross section of the
pump unit according to the modified example of the third
embodiment.
[0048] FIGS. 14A and 14B are a side view and a plan view of the
lawn mower, to which the pump unit of a fourth embodiment of the
present invention has been applied.
[0049] FIG. 14C is a plan view of the lawn mower, to which the pump
unit according to a modified example of the fourth embodiment has
been applied.
[0050] FIG. 15 is a hydraulic circuit diagram of the pump unit of
the fourth embodiment.
[0051] FIG. 16 is a plan view in horizontal cross section of the
pump unit according to the fourth embodiment.
[0052] FIG. 17 is a side view in vertical cross section of the pump
unit of FIG. 16.
[0053] FIG. 18 is a cross section taken along the line XVIII-XVIII
in FIG. 16.
[0054] FIG. 19 is a cross section taken along the line XIX-XIX in
FIG. 16.
[0055] FIG. 20 is a plan view of the pump unit equipped with a
hydraulic brake mechanism according to another embodiment with a
part in horizontal cross section.
[0056] FIGS. 21A and 21B are a side view and a plan view of the
lawn mower, to which the pump unit of a fifth embodiment of the
present invention has been applied.
[0057] FIG. 21C is a plan view of the lawn mower, to which the pump
unit according to a modified example of the fifth embodiment has
been applied.
[0058] FIG. 22 is a plan view in horizontal cross section of the
pump unit according to the fifth embodiment.
[0059] FIG. 23 is a cross section taken along the line XXIII-XXIII
in FIG. 22.
[0060] FIG. 24 is a cross section taken along the line XIV-XIV in
FIG. 22.
[0061] FIGS. 25A and 25B are a side view and a plan view of the
lawn mower, to which the pump unit of a sixth embodiment of the
present invention has been applied.
[0062] FIG. 26 is a side view in vertical cross section of the pump
unit according to the sixth embodiment.
[0063] FIG. 27 is a plan view of the lawn mower, to which the pump
unit of a seventh embodiment of the present invention has been
applied.
[0064] FIG. 28 is a plan view in horizontal cross section of the
pump unit according to the seventh embodiment of the present
invention.
[0065] FIG. 29 is a plan view of the lawn mower, to which the pump
unit of a modified example of the seventh embodiment has been
applied.
[0066] FIG. 30 is a plan view in horizontal cross section of the
pump unit according to the seventh embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
First Embodiment
[0067] The description will be made for the first embodiment of the
present invention with reference to the accompanied drawings.
[0068] The pump unit according to the present invention is fluidly
connected to an actuator via a hydraulic circuit for a cooperative
operation, in which the actuator is driven by the effect of
pressurized hydraulic fluid in the hydraulic circuit. This
embodiment will be hereinafter described by taking for example the
case where a hydraulic motor unit is used as the actuator.
[0069] FIGS. 1A and 1B are respectively a side view and a plan view
of a lawn mower 100A, to which a pump unit 1 of this embodiment has
been applied. FIG. 2 is a hydraulic circuit diagram of the pump
unit 1. FIGS. 3 and 4 are respectively a plan view in horizontal
cross section and a side view in vertical cross section of the pump
unit according to this embodiment.
[0070] Now, the description will be made for the lawn mower
100A.
[0071] As illustrated in FIGS. IA and 1B, the lawn mower 100A
includes a vehicle frame 110, a pair of laterally disposed driving
wheels (rear wheels in this embodiment) 120 supported by the
vehicle frame 110 so as to be located closer to a first side of the
lawn mower (a rear side in this embodiment), a pair of laterally
disposed casters 130 supported by the vehicle frame 110 so as to be
located closer to a second side of the lawn mower (a front side in
this embodiment), a working unit (mower unit in this embodiment)
140 supported by the vehicle frame 110 so as to be located between
the pair of laterally disposed driving wheels 120 and the pair of
laterally disposed casters 130, a driving source 150 supported by
the vehicle frame 110 so as to be located opposite to the working
unit 140 with the driving wheels 120 therebetween relative to a
fore and aft direction of the vehicle (that is, located closer to
the rear side in this embodiment), and first and second hydraulic
motor units 160a, 160b having motor shafts respectively and
operatively connected to the pair of laterally disposed driving
wheels 120, as well as the pump unit 1 of this embodiment.
[0072] As illustrated in FIGS. 1 and 2, the pump unit of this
embodiment is fluidly connected via a hydraulic circuit to the
hydraulic motor units 160a, 160b, which are located away from the
pump unit 1, and is designed to receive driving power from the
driving source 150 and let the working units 160a, 160b drive the
driving wheels 120 by utilizing the hydraulic effect of the
hydraulic circuit. That is, the pump unit 1 constitutes the running
power transmission path as a main transmission path in cooperation
with the hydraulic motor units 160a, 160b.
[0073] The pump unit 1 is also designed to be capable of taking off
power from the main transmission path and outputting the same as
driving power for the working unit 140. That is, the pump unit also
constitutes a part of the PTO power transmission path.
[0074] More specifically, as illustrated in FIGS. 3 and 4, the pump
unit 1 includes an input shaft 80 operatively connected to the
driving source 150, a first pump shaft 10a operatively connected to
the input shaft 80, a first hydraulic pump body 20a to be driven by
the first pump shaft 10a, a second pump shaft 10b operatively
connected to the input shaft 80 or the first pump shaft 10a, a
second hydraulic pump body 20b to be driven by the second pump
shaft 10b, a pump case 30 for accommodating the first hydraulic
pump body 20a and the second hydraulic pump body 20b and having a
first opening 30a through which the first and second hydraulic pump
bodies 20a, 20b pass into and out of the pump case 30, a center
section 40 connected to the pump case 30 so as to close the first
opening 30a while supporting the first and second hydraulic pump
bodies 20a, 20b, and a PTO unit 50 accommodated within the pump
case 30. The pump case 30 forms a hydraulic fluid sump.
[0075] As illustrated in FIG. 2, the first hydraulic pump body 20a
and the second hydraulic pump body 20b are respectively and fluidly
connected to the first hydraulic motor unit 160a and the second
hydraulic motor unit 160b via the hydraulic circuit (a pair of
hydraulic lines 200a and a pair of hydraulic lines 200b in this
embodiment).
[0076] The pump unit 1 of this embodiment is designed to have the
pair of hydraulic pump bodies 20a, 20b which respectively
correspond to the pair of laterally disposed hydraulic motor units
160a, 160b so that the pair of driving wheels 120 can be driven at
rotational speeds independently of each other. That is, the pump
unit 1 of this embodiment is designed so as to have the first
hydraulic pump body 20a and the second hydraulic pump body 20b
arranged respectively corresponding to the first hydraulic motor
unit 160a and the second hydraulic motor unit 160b. However, the
present invention is not necessarily limited to this arrangement.
The arrangement with only a single hydraulic pump body or with
three or more hydraulic pump bodies accommodated within the pump
case 30 also falls within the scope of the present invention. For
example, where the pump unit 1 is provided with only a single
hydraulic pump body, the single hydraulic pump body is fluidly
connected to the pair of laterally disposed hydraulic motor units
160a, 160b via a hydraulic circuit having a fluid dividing means
such as a flow dividing valve.
[0077] At least one of the hydraulic pump bodies 20a, 20b and the
hydraulic motor units 160a, 160b, which are respectively fluidly
connected to each other, is of a variable displacement type that
varies the suction/discharge rates by the operation of an output
adjustment member. Accordingly, output with variable speed can be
produced through motor shafts of the hydraulic motor units by
controlling the slanting angle of the output adjustment member. In
this embodiment, the hydraulic pump bodies 20a, 20b are of the
variable displacement type, while the hydraulic motor units 160a,
160b are of a fixed displacement type.
[0078] As best illustrated in FIG. 3, the input shaft 80 has an
upstream end with respect to the power transmission direction (a
rear end in this embodiment) supported by the pump case 30 so as to
extend outwards through the pump case 30 and operatively connected
to the driving source 150 via a flywheel 155. The flywheel 155 may
be provided with a damper 156 (see FIG. 1), thereby enabling power
to be transmitted from the driving source 150 to the input shaft
80, while limiting variation in angular speed of the output shaft
of the driving source 150. As a result, durability of the hydraulic
pump bodies 20a, 20b can be improved, hence achieving improved
durability of the hydraulic motor units 160a, 160b thanks to
limited pulsation of hydraulic fluid discharged from the hydraulic
pump bodies 20a, 20b.
[0079] In this embodiment, as illustrated in FIG. 1, the driving
source 150 is supported on the vehicle frame 110 in vibration free
manner, while the pump case 30 is fixedly supported on the vehicle
frame 110. This arrangement causes difference in vibration between
the driving source 150 and the pump case 30. In order to absorb
this vibration difference, in this embodiment, the driving source
150 is operatively connected to the input shaft 80 by a
vibration-absorbing transmission means. In this embodiment, as
illustrated in FIG. 1, transmission shaft 170 having universal
joints at the opposite ends is used as the vibration-absorbing
transmission means. Instead, a belt transmission mechanism may be
employed.
[0080] As illustrated in FIG. 3, the first pump shaft 10a is
supported on the pump case 30 so as to be arranged substantially
parallel to the input shaft 80, and operatively connected to the
input shaft 80 via a power transmission mechanism 90. In this
embodiment, the power transmission mechanism 90 includes a
drive-side gear 91 disposed non-rotatably relative to the input
shaft 80 and a driven-side gear 92 disposed non-rotatably relative
to the first pump shaft 10a so as to be in meshed engagement with
the drive-side gear 91.
[0081] The first hydraulic pump body 20a includes a piston unit 21a
that performs a rotational movement around the axis of the first
pump shaft 10a by the rotation of the first pump shaft 10a and a
reciprocal movement in association with the rotational movement, a
cylinder block 22a that supports the piston unit 312, allowing it
to freely reciprocate, and is rotatably and slidably supported on
the center section 40 so as to be in communication with the pair of
hydraulic lines 200a, and an output adjusting member 23a (a
combination of a movable swash plate and an operational shaft in
this embodiment), which regulates the stroke length of the piston
unit 21a according to the slanting angle so as to vary the
suction/discharge rates of the piston unit 21a. In this embodiment,
although the hydraulic pump bodies 20a, 20b are of an axial piston
type, it is possible to be of a radial piston type.
[0082] The second pump shaft 10b is supported on the pump case 30
so as to be arranged substantially parallel to the first pump shaft
10a. The second pump shaft 10b is operatively connected to the
input shaft 80 or the first pump shaft 10a via a transmission
mechanism 60 accommodated within the pump case 30 so as to be
rotated in synchronization with the first pump shaft 10a. In this
embodiment, the transmission mechanism 60 includes a first gear 61
supported relatively non-rotatably on the first pump shaft 10a, and
a second gear 62 having the same pitch as the first gear 61 and
relatively non-rotatably supported on the second pump shaft 10b so
as to be in meshed engagement with the first gear 61.
[0083] The second hydraulic pump body 20b has substantially the
same structure as that of the first hydraulic pump body 20a except
that the second hydraulic pump body 20b is driven by the second
pump shaft 10b. Accordingly, the detailed description of the second
hydraulic pump body 20b will be omitted.
[0084] As best illustrated in FIG. 3, the PTO unit 50 includes a
PTO shaft 51 and a hydraulic clutch mechanism 55. In this
embodiment, the PTO shaft 51 is aligned coaxially with the input
shaft 80 and supported on the pump case 30 so as to have an outer
end. In this embodiment, the end of the PTO shaft 51 extends
forwards in the fore and aft direction of the vehicle.
[0085] More specifically, the PTO shaft 51 is aligned coaxially
with the input shaft 80 in operative connection to the input shaft
80 via the drive-side gear 91, the driven-side gear 92, the first
pump shaft 10a, the first gear 61 and the hydraulic clutch
mechanism 55, so that driving power from the input shaft 80 is
selectively input to the PTO shaft 51 by the hydraulic clutch
mechanism 55. The outer end of the PTO shaft 51 is operatively
connected to an input part of the working unit 140 via a
vibration-absorbing transmission means. In this embodiment,
transmission shaft 175 having universal joints at the opposite ends
is used as the vibration-absorbing transmission means, as
illustrated in FIG. 1.
[0086] The coaxial arrangement of the input shaft 80 and the PTO
shaft 51 in the pump unit 1 of this embodiment produces the
following effects:
[0087] As illustrated in FIG. 1B, the coaxial arrangement of the
input shaft 80 and the PTO shaft 51 can achieve the sub
transmission path extending from the driving source 150 to the
working unit 140 in a linear fashion, and hence occupation of less
space.
[0088] Where the connections between the driving source 150 and the
input shaft 80 and between the PTO shaft 51 and the working unit
140 are respectively made by the transmission shafts 170, 175, the
coaxial arrangement of the input shaft 80 and the PTO shaft 51 can
reduce the load applied to connection areas between these shafts,
hence achieving improved durability of the connection areas and
prevention of noises and vibrations. Specifically, the output shaft
of the driving source 150 and the input part of the working unit
140 are preferably located substantially along the longitudinal
center axis of the vehicle in terms of the weight balance (see FIG.
1B). In this preferable arrangement, when the input shaft 80 and
the PTO shaft 51 are offset to either lateral side from the
longitudinal center axis of the vehicle, the transmission shaft 170
between the driving source 150 and the input shaft 80, or the
transmission shaft 175 between the PTO shaft 51 and the working
unit 140 must be tilted at an angle relative to the longitudinal
center axis. In order to achieve this orientation of the
transmission shaft, the universal joints at the opposite ends
thereof are required to forcibly change the rotational axis of
driving power to be transmitted. This causes a large load on these
universal joints.
[0089] On the contrary, in this embodiment, as described above, the
input shaft 80 is aligned coaxially with the PTO shaft 51. This
arrangement allows the transmission shafts 170, 175 to be aligned
parallel to the longitudinal center axis of the vehicle. As a
result, it is possible to reduce the load applied on the universal
joints provided on the transmission shafts 170, 175.
[0090] Further, the PTO shaft 51 is vertically offset from the
input part of the working unit 140 in consideration of the lifting
height of the working unit 140. Specifically, when the working unit
140 is at an operational position (a position in contact with a
land), the transmission shaft 175 is tilted forwardly downwardly
(see FIG. 1A), while at an inoperative position (a withdrawal
position), the transmission shaft 175 is horizontally oriented or
is tilted forwardly upwardly (not shown).
[0091] The universal joints can permit variation of tilting angle
of the transmission shaft 175 to some extent. However, when the PTO
shaft 51 and the input part of the working unit 140 are offset from
each other in the lateral direction of the vehicle, lateral bending
as well as vertical vending are caused in, the universal joints. As
a result, "three-dimensional bending" occurs in the universal
joints. On the contrary, as described above, the coaxial
arrangement of the PTO shaft 51 and the input shaft 80 can omit the
possibility to cause lateral bending and hence achieve the
reduction of the load applied on the universal joints.
[0092] The hydraulic clutch mechanism 55 is designed to selectively
enable and disable power transmission from the input shaft 80 to
the PTO shaft 51 by the hydraulic effect. In this embodiment, as
best illustrated in FIG. 3, the hydraulic clutch mechanism 55
includes a drive-side member 55a relatively rotatably and axially
non-slidably supported on the PTO shaft 51, while being operatively
connected to the input shaft 80, a drive-side friction plate 55b
relatively non-rotatably and axially slidably supported on the
drive-side member 55a, a driven-side member 55c relatively
non-rotatably supported on the PTO shaft 51, a driven-side friction
plate 55d relatively non-ratably supported on the driven-side
member 55c in such a manner as to be axially slidable within a
certain area, a clutch pressing member 55e for bringing the
driven-side friction plate 55d into frictional engagement with the
drive-side friction plate 55b upon receiving the hydraulic effect,
and a clutch biasing member 55f for biasing the clutch pressing
member 55e in a direction away from the drive-side friction plate
55b and the driven-side friction plate 55d.
[0093] The thus arranged hydraulic clutch mechanism 55 transmits
power from the input shaft 80 to the PTO shaft 51 via the
drive-side member 55a and the driven-side member 55c when the
clutch pressing member 55e has brought both the friction plates
55b, 55d into frictional engagement with each other by the
hydraulic effect, and disables power transmission from the input
shaft 80 to the PTO shaft 51 when the hydraulic effect is not
applied.
[0094] The pump case 30 is designed to be capable of accommodating
the first and second hydraulic pump bodies 20a, 20b, and the
hydraulic clutch mechanism 55 of the PTO unit 50. More
specifically, the pump case 30 includes a hollowed case body 31
having first and second end walls 31a, 31b respectively located
closer 2 to the first and second sides along the longitudinal axis
of the vehicle (front and rear sides in this embodiment), and a
peripheral wall 31c extending between peripheral edges of the first
and second end walls 31a, 31b.
[0095] The first end wall 31a has on a first lateral side in the
vehicle width direction a first opening 30a, through which the
first and second hydraulic pump bodies 20a, 20b can pass into and
out of the case body 31, while the second end wall 31b has on a
second side in the vehicle width direction a second opening 30b,
through which the PTO unit 50 can pass into and out of the case
body 31.
[0096] With the above arrangement, the case body 31 defines a
hydraulic-pump-body-accommodation space 30A located closer to the
first lateral side of the vehicle in communication with the first
opening 30a, and a hydraulic-clutch-mechanism-accommodation space
30B located closer to the second lateral side of the vehicle in
communication with the second opening 30b.
[0097] Preferably, the case body 31 has a partition wall 31d for
dividing the hydraulic-pump-body-accommodation space 30A from the
hydraulic-clutch-mechanism-accommodation space 30B so as to
effectively prevent metallic dust or the like generated by the
frictional engagement between the friction plates in the hydraulic
clutch mechanism 55 from directly flowing into the
hydraulic-pump-body-accommodation space 30A.
[0098] The pump case 30 further includes a lid member 32 connected
to the case body 31 so as to cover substantially the entire surface
of the second end wall 31b located on the second side of the fore
and aft direction of the vehicle, thereby closing the second
opening 30b. The lid member 32 is connected to the second end wall
31b, leaving an accommodation space between the lid member 32 and
the second end wall 31b of the case body 31. This accommodation
space is to accommodate the transmission mechanism 90 for operative
connection between the input shaft 80 and the first pump shaft 10a
(the drive-side gear 91 and the driven-side gear 92 in this
embodiment) enabling them to be operated in association with each
other, and the transmission mechanism 60 for operative connection
between the first pump shaft 10a and the second pump shaft 10b (the
first and second gears 61, 62 in this embodiment) enabling them to
be operated in association with each other. Preferably, filters or
oil seals (not shown) are respectively provided in clearances
between the inner circumferences of first- and
second-pump-shaft-insertion holes provided in the second end wall
31b and the outer circumferences of the pump shafts 10a, 10b so
that metallic dust or the like can be prevented from flowing into
the hydraulic-pump-body-accommodation space 30A.
[0099] The first opening 30a is closed by the center section 40.
That is, the center section 40 is connected to the first end wall
31a so as to close the first opening 30a, while supporting the
first and second hydraulic pump bodies 20a, 20b on a surface 40a
facing the case body 31.
[0100] Preferably, the first pump shaft 10a has a downstream end
with respect to the power transmission direction, which extends
outwards through the center section 40, and a charge pump unit 70
is mounted on a surface 40b opposite to the hydraulic-pump-support
surface 40a so as to be driven through the downstream end of the
first pump shaft 10a. As used throughout the description, the
directional term "upstream" and "downstream" are relative to the
driving-power transmission direction.
[0101] In order to drive the charge pump unit 70, the second pump
shaft 10b may be extended through the center section 40 to have an
outside end, through which the charge pump unit 70 is driven.
Alternatively, both the first pump shaft 10a and the second pump
shaft 10b are extended through the center section 40 to
respectively have outside ends, so that the charge pump unit 70 is
driven through either one of the outside ends, while a cooling fan
(not shown) is driven through the residual one of the outside ends.
The charge pump unit 70 is used as a fluid-supply source for
supplying pressurized charge fluid to the hydraulic circuit between
the first and second hydraulic pump bodies 20a, 20b and the
hydraulic motor units 160a, 160b, as well as a fluid-supply source
for supplying operating fluid for the hydraulic clutch mechanism 55
in the PTO unit 50.
[0102] Preferably, the pump case 30 includes a seal-plate 33 to be
connected to the first end wall 31a. The seal plate 33 acts as a
sealing means for liquid-tightly sealing a bearing hole for the PCT
shaft 51 formed in the first end wall 31a, and forms a part of the
hydraulic circuit for fluid connection between the charge pump unit
70 and the hydraulic clutch mechanism 55. The pump case 30 is thus
liquid-tightly sealed by the respective parts so as to be capable
of storing hydraulic fluid in the inner space.
[0103] Further, the PTO unit 50 preferably includes a hydraulic
brake mechanism 58 operable in association with clutching action of
the hydraulic clutch mechanism 55 so as to be capable of
effectively preventing the PTO shaft 51 from continuing to rotate
by inertia of the working unit 140 connected thereto, when the
hydraulic clutch mechanism 55 has disabled the power
transmission.
[0104] The hydraulic brake mechanism 58 includes a brake disc 58a
(an outer circumference of the driven-side member 55c of the
hydraulic clutch mechanism 55 in this embodiment) non-rotatable
relative to the PTO shaft 51, a brake shoe 58b disposed so as to be
capable of being frictionally engaged with the brake disc 58a, a
brake pressing member 58c having a distal end supporting the brake
shoe 58b and a proximal end axially slidably supported on a
cylinder chamber 58A provided in the pump case 30, and a brake
biasing member 58d for biasing the brake pressing member 58c so as
to bring the brake shoe 58b into frictional engagement with the
brake disc 58a.
[0105] The thus arranged hydraulic brake mechanism 58 is of a
negative brake system. That is, when the brake pressing member 58c
is not subjected to the hydraulic effect, the brake shoe 58b is
held in frictional engagement with the brake disc 58a by the
biasing force of the brake biasing member 58d, thereby applying
braking force to the PTO shaft 51. On the other hand, when the
brake pressing member 58c is subjected to the hydraulic effect, the
brake pressing member 58c is moved away from the brake shoe 58b
against the biasing force of the brake biasing member 58d, thereby
applying no braking force to the PTO shaft 51.
[0106] More preferably, the cylinder chamber 58A is formed by the
peripheral wall 31c of the case body 31 and a cover 59 connected
thereto. That is, the cylinder chamber 58A, which requires to
provide liquid-tight capability, is formed not in the case body 31
but in the cover 59. Whereby, it is not necessary to increase
machining precision of the case body 31, and hence it is possible
to relatively easily form the case body 31 by casting.
[0107] The application of the hydraulic effect to the brake
pressing member 58c is made in association with the application of
the hydraulic effect to clutch pressing member 55e of the hydraulic
clutch mechanism 55. That is, when the hydraulic clutch mechanism
55 is brought into "engaging state" by hydraulic pressure applied
to the clutch pressing member 55e, the hydraulic brake mechanism is
brought into "breaking-force releasing state" since hydraulic
pressure is also applied to the brake pressing member 58c. On the
other hand, when hydraulic pressure is not applied to the clutch
pressing member 55e and therefore the hydraulic clutch mechanism is
brought into "disengaging state", the hydraulic brake mechanism 58
is brought into "breaking-force applying state" since hydraulic
pressure is not applied also to the brake pressing member 58c.
[0108] Specifically, as illustrated in FIG. 2, the hydraulic brake
mechanism 58 and the hydraulic clutch mechanism 55 are controlled
by a common hydraulic source (the charge pump unit 70 in this
embodiment) so as to be operated in association with each
other.
[0109] Now, the description will be made for the hydraulic circuit
of the pump unit 1 with reference to FIGS. 2 and 3.
[0110] The charge pump unit 70 has an inlet port 70a connected to
an optional outside tank 300 (see FIG. 2) or to the pump case 30,
via a filter 310 (see FIG. 2), and an outlet port 70b connected to
a main pressurized-fluid line 320. The main pressurized-fluid line
320 is divided into a charge line 321 and an operating fluid line
322 at a pressure reducing valve 350 for charge pressure setting.
More specifically, the main pressurized-fluid line 320 and the
charge line 321 are respectively connected to the upstream and
downstream sides of the pressure reducing valve 350 so that surplus
hydraulic fluid resulting from the pressure reducing operation of
the pressure reducing valve 350 flows into the operating fluid line
322.
[0111] Connected to the main pressurized-fluid line 320 are a
pressure setting line 323 with a first relief valve 351 placed
therein and a suction line 324 with a check valve 352 placed
therein. The suction line 324 is provided to prevent occurrence of
negative pressure in a hydraulic circuit between the hydraulic pump
bodies 20 and the hydraulic motor units 160 (the pair of hydraulic
lines 200a and the pair of hydraulic lines 200b in this embodiment)
in the event of emergency or the like.
[0112] The charge line 321 is communicated respectively with the
pair of hydraulic lines 200a and the pair of hydraulic lines 200b
via check valves 353. More specifically, the center section 40 has
a pair of hydraulic passages 201a that respectively form parts of
the pair of hydraulic lines 200a, and a pair of hydraulic passages
201b that respectively form parts of the pair of hydraulic lines
200b, in which the charge line 321 is communicated with the pair of
hydraulic passages 201a and the hydraulic passages 201b via the
check valves 353 (see FIG. 2).
[0113] Preferably, each of the pair of hydraulic passages 201a and
each the pair of hydraulic passages 201b respectively have ends
opening to the outside through the same side of an peripheral wall
of the center section 40 to respectively form fluid connection
ports for connection with the first and second hydraulic motor
units 160a, 160b.
[0114] Further, the center section 40 has bypass lines 325 for
communication between the pair of hydraulic passages 201a (i.e.,
between the pair of hydraulic lines 200a) and communication between
hydraulic passages 201b (i.e., between the pair of hydraulic lines
200b). Switching members 354 for communication and shutoff between
the pair of hydraulic passages 201a and between the pair of
hydraulic passages 201b are placed in the bypass lines 325 in such
a manner as to be operable from the outside. The switching members
354 are used to force the pair of hydraulic lines 200a into
communication with each other and the pair of hydraulic lines 200b
into communication with each other, thereby allowing the motor
shafts of the hydraulic motor units 160a, 160b to freely rotate, in
the event of failure of the pump unit or the like, where the
vehicle must be forcibly moved.
[0115] The operating fluid line 322 is communicated via a switching
valve 360 with a clutch line 326, which is in turn communicated
with a brake line 327. Accordingly, the switching valve 360 is
controllable to supply pressurized hydraulic fluid and shut off the
supply of the same from the operating fluid line 322 to the clutch
line 326 and the brake line 327, that is, to the hydraulic clutch
mechanism 55 and the hydraulic brake mechanism 58 in association
with each other.
[0116] Second relief valve 361 for pressure setting is placed in
the clutch line 326 so as to set the maximum hydraulic pressure in
each of the clutch line 326 and the brake line 327. The downstream
side of the second relief valve 361 is communicated with the pump
case 30.
[0117] The pressure reducing valve 350, the check valve 352, the
first relief valve 351, the switching valve 360 and the second
relief valve 361 are mounted in, for example, a charge pump case 72
of the charge pump unit 70.
[0118] More preferably, the hydraulic brake mechanism 58 is
provided with an accumulator means 57 for absorbing switching shock
caused when the hydraulic clutch mechanism 55 is switched from the
power shutoff state to the power transmission state (see FIG. 2).
Specifically, the brake pressing member 58c is provided with a rod
57a having a proximal end located within the cylinder chamber 58A
and a distal end on which the brake shoe 58b is supported, a
pressure receiving plate 57b axially slidably supported on the rod
57a and arranged so as to divide the cylinder chamber 58A into a
pressurized-fluid actuation chamber and a biasing-member
accommodation chamber, and a follow plate 57c axially non-movably
supported on the rod 57a so as to be located within the
biasing-member accommodation chamber.
[0119] The pressure receiving plate 57b has an orifice 57b' for
communication between the pressurized-fluid actuation chamber and
the biasing-member accommodation chamber. The orifice 57b' is
closed by the follow plate 57c when it has been pressed by a
predetermined stroke upon receiving the effect of pressurized
hydraulic fluid.
[0120] The thus provided accumulator means 57 can produce the
following effects:
[0121] When the switching valve 360 is held at the
pressurized-fluid supply position so as to bring the hydraulic
clutch mechanism 55 into the "engaging state", while bringing the
hydraulic brake mechanism 58 into the "breaking-force releasing
state", pressurized hydraulic fluid is supplied into the clutch
line 326 and the brake line 327. In an initial stage in which
pressurized hydraulic fluid has started to be supplied into the
pressurized-fluid actuation chamber via the brake line 327,
pressurized hydraulic fluid leaks through the orifice 57b'. This
leakage allows the hydraulic pressure of the clutch line 326 and
the brake line 327 to relatively gradually increase. Accordingly,
relatively gentle clutch engagement of the hydraulic clutch
mechanism 55 is achieved. Then, the pressure receiving plate 57b is
pressed through pressurized hydraulic fluid, thereby closing the
orifice 57b'. Accordingly, the hydraulic pressure of the clutch
line 326 and the brake line 327 is increased to a set value of the
second relief valve 361.
[0122] Thus, in this embodiment, hydraulic pressure in the clutch
line 326 can be gradually increased until the orifice 57b' is
closed by the pressure receiving plate 57b after it is pressed by a
predetermined stroke. Accordingly, it is possible to prevent abrupt
clutch engagement of the hydraulic clutch mechanism 55, and hence
wear-out and damages of the respective parts.
[0123] In addition to the effects as described above, the thus
arranged pump unit 1 can produce the following effects:
[0124] By the pump unit 1, which is so arranged that pressurized
hydraulic fluid can be supplied into the hydraulic motor units
1G0a, 160b by driving power from the driving source 150, and
driving power from the driving source 150 is taken out by the PTO
shaft 51 and output therefrom, the main transmission path and the
sub transmission path that can be controlled independently of each
other can be easily formed.
[0125] The above described arrangement, which makes the hydraulic
clutch mechanism 55 accommodated within the pump case 30 enable and
disable the power transmission in the sub transmission path,
contributes to an improved durability as compared with a
conventional arrangement, which makes an electromagnetic clutch
perform the same function.
[0126] Further, the above described arrangement, in which the
supply of pressurized hydraulic fluid to the hydraulic clutch
mechanism 55 is made by the charge pump unit 70 connected to the
pump case 30 and driven by the first pump shaft 10a, can contribute
to a shortened and pressurized-fluid supply circuit.
[0127] It is a matter of course that the respective constitutional
elements of the pump unit 1 are not necessarily limited to those in
this embodiment, but can be subjected to various modifications or
replacement with others. For example, in place of the hydraulic
brake mechanism 58, a hydraulic brake mechanism 58' as illustrated
in FIG. 5 can be used. The hydraulic brake mechanism 58' includes a
friction brake plate 58a' relatively non-rotatably and axially
slidably supported on the PTO shaft 51, a fixed friction plate 58b'
fixed to the case body 31, and a brake pressing member 58c' for
pressing both the friction plates 58a', 58 into contact with each
other, in which the brake pressing member 58c' is designed to be
operated in association with the clutch pressing member 55e via a
connection member 58d'.
[0128] That is, when the clutch pressing member 55e is pressed by
the hydraulic effect so as to bring the drive-side friction plate
55b into frictional engagement with the driven-side friction plate
55d, the brake pressing member 58c' is moved away from the friction
brake plate 58a' and the fixed friction plate 58b' in association
with the action of the clutch pressing member 55e. On the other
hand, when the clutch pressing member 55e is moved away from the
drive-side friction plate 55b and the driven-side friction plate
55d by the effect of the clutch biasing member 55f, the brake
pressing member 55c' brings the friction brake plate 58a' into
frictional engagement with the fixed friction plate 58b' in
association with the action of the clutch pressing member 55e. With
the arrangement using the thus constructed hydraulic brake
mechanism 58', it is also possible to effectively prevent the PTO
shaft 51 from continuing to rotate by inertia even after power to
the PTO shaft 51 has been shut off.
Second Embodiment
[0129] The description will be made for the second embodiment of
the present invention with reference to the accompanied drawings.
FIG. 6 is a plan view of a lawn mower 100B, to which a pump unit 2
of this embodiment has been applied, and FIG. 7 is a plan view in
horizontal cross section of the pump unit 2 according to this
embodiment. In the following description, corresponding or
identical parts to those of the first embodiment have been given
the same reference characters to omit a detailed description
thereof.
[0130] While the pump unit 1 of the first embodiment is fixedly
supported by the vehicle frame 110, the pump unit 2 of this
embodiment is integrally connected to the driving source 150, as
illustrated in FIGS. 6 and 7.
[0131] As illustrated in FIG. 7, the driving source 150 has a mount
flange 151, to which a flywheel housing 157 is connected. The
flywheel housing 157 has a peripheral wall 157a connected to the
mount flange 151 and extending in the power transmission direction
(in the fore and aft direction of the vehicle in this embodiment),
and end wall 157b extending from a downstream end (a front end in
this embodiment) of the peripheral wall 157a.
[0132] The case body 31 is connected to the flywheel housing 457
via the second end wall 31b in a free state relative to the vehicle
frame 110. Preferably, the second end wall 31b of the case body 31
is connected to the end wall 157b of the flywheel housing 157,
leaving a space therebetween. The space acts as an accommodation
space for the first and second gears 61, 62, the drive-side gear 91
and the driven-side gear 92. In this embodiment, the end wall 157b
of the flywheel housing 157 has a recess, which forms the
accommodation space.
[0133] The input shaft 80 has an upstream end directly connected to
an output part of the damper 156 in the flywheel 155, while being
bearing-supported by the end wall 157b of the flywheel housing 157.
Reference numeral 152 in FIG. 7 represents an output shaft of the
driving source 150.
[0134] In addition to the effects in the first embodiment, the pump
unit 2 produces the following effects:
[0135] The pump unit 2, which is integrally connected to the
driving source 150 that is supported on the vehicle frame 110 in
vibration free manner, does not cause vibration difference between
the driving source 150 and the pump unit 2. As a result, it is
possible to omit the vibration-absorbing transmission means between
the driving source 150 and the pump unit 1, which is used in the
first embodiment, thereby achieving reduced production cost. Also,
the length between the driving source 150 and the pump unit 2 can
be shortened. Since vibrations due to pulsation of hydraulic fluid
cased by the actuation of the hydraulic pump bodies 20a, 20b are
absorbed by utilizing a vibration absorption material interposed
between the driving source 150 and the vehicle frame 110,
vibrations are unlikely to transmit to the vehicle body, which
contributes to improved driving environment.
Third Embodiment
[0136] The description will be made for the third embodiment of the
present invention with reference to the accompanied drawings. FIGS.
8A and 8B are a side view and a plan view of a lawn mower 100 C, to
which a pump unit 3 of the third embodiment has been applied. FIGS.
9 and 10 are a plan view in horizontal cross section and a side
view in vertical cross section of the pump unit 3 of the third
embodiment. FIG. 11 is a cross section taken along the line XI-XI
in FIG. 9.
[0137] In the following description, corresponding or identical
parts to those of the first or second embodiment have been given
the same reference characters to omit a detailed description
thereof.
[0138] In the pump unit 3 of this embodiment, the PTO shaft in the
pump unit 1 of the first embodiment is modified so as to extend in
the vertical direction. More specifically, the pump unit 3 of this
embodiment includes a PTO unit 450 in place of the PTO unit 50, and
a pump case 430 in place of the pump case 30.
[0139] The PTO unit 450 includes a PTO shaft 451 that extends
vertically so as to be substantially orthogonal to the input shaft
80 arranged parallel to the longitudinal axis of the vehicle and
that has the same axial position in the width direction of the
vehicle as the input shaft 80, and a hydraulic clutch mechanism 455
for enabling and disabling power transmission from the input shaft
80 to the PTO shaft 451.
[0140] The PTO shaft 451 has a downstream end supported by the pump
case 430 so as to extend vertically and outwardly through the pump
case 430. In this embodiment, as best illustrated in FIGS. 10 and
11, the downstream end extends downwards from the pump case 430.
The downstream end of the PTO shaft 451 is operatively connected to
the input part of the working unit 140 via the vibration-absorbing
transmission means in the same manner as the first embodiment. In
this embodiment, as the vibration-absorbing transmission means, a
belt transmission mechanism 176 is employed (see FIGS. 10 and
11).
[0141] The hydraulic clutch mechanism 455 includes a drive-side
member 455a that is relatively rotatably and axially non-slidably
supported on the PTO shaft 451, and operatively connected to the
first pump shaft 10a. In this embodiment, as described above, the
PTO shaft 451 is located orthogonal to the input shaft 80 so that
the drive-side member 455a is operatively connected to the input
shaft 80 via a direction-changing power transmission mechanism 460.
In this embodiment, the direction-changing power transmission
mechanism 460 includes a bevel gear provided to the drive-side
member 455a, and an intermediate bevel gear 463 relatively
non-rotatably supported on the input shaft 80 in meshed engagement
with the bevel gear. In this embodiment, the drive-side gear 91,
which is relatively non-rotatably supported on the input shaft 80,
is arranged to be meshed with the first gear 61, which is
relatively non-rotatably supported on the first pump shaft 10a, so
that the input shaft 80 and the first pump shaft 10a are
operatively connected to each other via the drive-side gear 91 and
the first gear 61.
[0142] The pump case 430 is a modified form resulting from a
partial modification of the pump case 30 in order to accommodate
the PTO unit 450. That is, as best illustrated in FIGS. 9 and 10, a
case body 431 in the pump case 430 has an intermediate wall 431d,
which extends from the peripheral wall 31c towards an opposite side
to the hydraulic-pump-body-accommodation space 30A. The
intermediate wall 431d and the lid member 32 together act as a
bearing of the input shaft 80. In this embodiment, the second
opening 30b, through which the hydraulic clutch mechanism 455 can
pass, is located above the intermediate wall 431d (see FIG.
10).
[0143] The pump case 430 in this embodiment includes a seal cap 433
connected to a bottom of the case body 431, in place of the seal
plate 33. In this embodiment, a pressurized-fluid supply line to
the hydraulic clutch mechanism 455 and the hydraulic brake
mechanism 58 (the clutch line 326 and the brake line 327) is formed
in the case body 431 (see FIG. 11). The operating fluid line 322,
which extends through the switching valve 360 located in the charge
pump unit 70, is connected to the pressurized-fluid supply line via
conduit (not shown).
[0144] The same effects as those in the first embodiment can also
be produced in this embodiment. Although the pump case 430 is
fixedly supported on the vehicle frame 110 with a distance away
from the driving source 150 in this embodiment.
[0145] Alternatively, the pump case 430 can be integrally connected
to the driving source 150 in the same manner as in the second
embodiment (see FIGS. 12 and 13). While the above embodiments were
described by taking for example the case where the pump unit is
operated in association with the driving source 150 of a horizontal
type, which has a horizontally extending output shaft, the pump
unit in each embodiment can be designed to be capable of being
operated in association with a driving source of a vertical type,
which has a vertically extending output shaft.
Forth Embodiment
[0146] The description will be made for the fourth embodiment of
the present invention with reference to the accompanied drawings.
FIGS. 14A and 14B are a side view and a plan view of a lawn mower
100D, to which a pump unit 4 of this embodiment has been applied.
FIG. 15 is a hydraulic circuit diagram of the pump unit 4. FIGS. 16
and 17 are a plan view in horizontal cross section and a side view
in vertical cross section of the pump unit 4 according to this
embodiment. FIGS. 18 and 19 are cross sections respectively taken
along the line XVIII-XVIII and XIX-XIX in FIG. 16. In the following
description, corresponding or identical parts to those of the
aforementioned embodiments have been given the same reference
characters to omit a detailed description thereof.
[0147] The pump unit 4 of this embodiment is designed to omit the
necessity to provide the input shaft 80 in the pump unit 1 of the
first embodiment, and input driving power from the driving source
150 to the first pump shaft 10a.
[0148] That is, as illustrated in FIGS. 16 and 17, the pump unit 4
includes the first pump shaft 10a operatively connected to the
driving source 150, the first hydraulic pump body 20a driven by the
first pump shaft 10a, the second pump shaft 10b operatively
connected to the first pump shaft 10a, the second hydraulic pump
body 20b driven by the second pump shaft 10b, the pump case 30
having the first opening 30a, through which the first hydraulic
pump body 20a and the second hydraulic pump body 20b can pass into
and out of the pump case 30, the center section 40 connected to the
pump case 30 so as to close the first opening 30a, while supporting
the first and second hydraulic pump bodies 20a, 20b, and the PTO
unit 50 accommodated in the center section 40.
[0149] As best illustrated in FIG. 16, the first pump shaft 10a is
supported by the pump case 30 so as to have the upstream end (rear
end in this embodiment) extending outwards through the pump case
30, and is operatively connected to the driving source 150 via the
flywheel 155.
[0150] In this embodiment, in the same manner as the first
embodiment, as illustrated in FIG. 14, the driving source 150 is
supported on the vehicle frame 110 in vibration free manner, while
the pump case 30 is fixedly supported on the vehicle frame 110.
Accordingly, the driving source 150 and the first pump shaft 10a
are operatively connected to each other via the vibration-absorbing
transmission means.
[0151] The second pump shaft 10b is supported by the pump case 30
so as to be arranged substantially parallel to the first pump shaft
10a. In this embodiment, the second pump shaft 10b is operatively
connected to the first pump shaft 10a via the transmission
mechanism 60 placed in the pump case 30 so as to be rotated
synchronously with the first pump shaft 10a. In this embodiment,
the transmission mechanism 60 includes the first gear 61 relatively
non-rotatably supported on the first pump shaft 10a, and the second
gear 62 having the same pitch as the first gear 61 and relatively
non-rotatably supported on the second pump shaft 10b so as to be in
meshed engagement with the first gear 61.
[0152] The hydraulic clutch mechanism of the pump unit 4 of this
embodiment is the same as that of the first embodiment, except that
the power transmission from the first pump shaft 10a to the PTO
shaft 51 is selectively enabled and disabled.
[0153] That is, the hydraulic clutch mechanism 55 of this
embodiment is the same as that of the first embodiment except that
the drive-side member 55a is operatively connected not to the input
shaft 80 but to the first pump shaft 10a.
[0154] The thus arranged hydraulic clutch mechanism 55 enables
power transmission from the first pump shaft 10a to the PTO shaft
51 via the drive-side member 55a and the driven-side member 55c
when the clutch pressing member 55e has brought the drive-side
friction plate 55b and the driven-side friction plate 55d into
frictional engagement with each other by the hydraulic effect, and
disables power transmission from the first pump shaft 10a to the
PTO shaft 51 when it is not subjected to the hydraulic effect.
[0155] The pump unit 4 of this embodiment has the pump case 30,
which is the same as the pump case of the first embodiment except
that the transmission mechanism 90 is not placed therein. That is,
in this embodiment, an accommodation space between the lid member
32 and the second end wall 31b of the case body 31 is designed to
accommodate only the transmission mechanism 60 for operative
connection between the first pump shaft 10a and the second pump
shaft 10b enabling them to be operated in association with each
other.
[0156] The pump unit 4 of this embodiment produces the same effects
as those of the first embodiment. Also, in this embodiment, various
modifications and replacements can be made in the same manner as
those in the first embodiment. For example, as illustrated in FIG.
20, it is possible to provide the hydraulic brake mechanism 58' in
place of the hydraulic brake mechanism 58 described in the first
embodiment.
[0157] In this embodiment, as best illustrated in FIG. 14B, the
first pump shaft 10a of the pump unit 4 and the output shaft of the
driving source 150 are located along the longitudinal center axis
of the vehicle. As a result, the PTO shaft 51 offset from the first
pump shaft 10a to either side relative to the longitudinal center
axis of the vehicle, and the input shaft of the working unit 140
located substantially along the longitudinal axis of the vehicle
are offset from each other in the width direction of the vehicle.
Alternatively to this arrangement, it is a matter of course to
locate the PTO shaft 51 along the longitudinal center axis of the
vehicle, as illustrated in FIG. 14C. Where the PTO shaft 51 is
located substantially along the longitudinal center axis of the
vehicle, the first pump shaft 10a is necessarily offset from the
output shaft of the driving source 150 in the width direction of
the vehicle. Therefore, in this arrangement, preferably, the first
pump shaft 10a is operatively connected to the output shaft of the
driving source 150 via a belt transmission mechanism.
Fifth Embodiment
[0158] The description will be made for the fifth embodiment of the
present invention with reference to the accompanied drawings. FIGS.
21A and 21B are a side view and a plan view of a lawn mower 100E,
to which a pump unit 5 of this embodiment has been applied. FIG.
21C is a plan view of the lawn mower, to which the pump unit
according to a modified example of this embodiment has been
applied. FIG. 22 is a plan view in horizontal cross section of the
pump unit 5 according to this embodiment. FIGS. 23 and 24 are cross
sections respectively taken along the line XXIII-XXIII and the line
XXIV-XXIV in FIG. 22. In the following description, corresponding
or identical parts to those of the aforementioned embodiment have
been given the same reference characters to omit a detailed
description thereof.
[0159] The pump unit 5 of this embodiment is modified so as to have
the PTO shaft extending in the vertical direction in the pump unit
4 of the fourth embodiment. More specifically, the pump unit 5 of
this embodiment has the PTO unit 450 and the pump case 430 of the
fourth embodiment in the pump unit 4 of the fourth embodiment.
[0160] The thus arranged pump unit 5 can produce the same effects
as those in the pump unit 4 of the fourth embodiment.
[0161] It is a matter of course that the pump unit 5 can be
supported on the vehicle frame 110 so as to have the PTO shaft 451
placed substantially in the middle of the width of the vehicle,
instead of having the pump unit 5 supported on the vehicle frame
110 so as to have the first pump shaft 10a placed in the same
position as the longitudinal center axis of the vehicle in the
vehicle width direction (see FIG. 21C).
Sixth Embodiment
[0162] The description will be made for the sixth embodiment of the
present invention with reference to the accompanied drawings. FIGS.
25A and 25B are a side view and a plan view of a lawn mower 100F,
to which a pump unit 6 of this embodiment has been applied. FIG. 26
is a side view in vertical cross section of the pump unit 6
according to this embodiment. In the following description,
corresponding or identical parts to those of the aforementioned
embodiments have been given the same reference characters to omit a
detailed description thereof.
[0163] While the pump units 4, 5 of the fourth and fifth
embodiments each are designed to be operated in association with
the driving source 150, which is a horizontal type that has the
horizontally extending output shaft, the pump unit 6 of the sixth
embodiment is designed to be operated in association with the
driving source 150', which is a vertical type that has the
vertically extending output shaft.
[0164] Specifically, as illustrated in FIG. 26, the first pump
shaft 10a is extended in the vertical direction. In this
embodiment, the first pump shaft 10a has a lower end extending
downwards from a pump case 530 and operatively connected to the
driving source 150' via a belt transmission mechanism 171.
[0165] The pump case 530 is the same in construction as the pump
case 30 in the fourth embodiment, except that the pump case 530 is
oriented in a different direction. That is, the pump case 530 is
fixed to the vehicle frame 110 so as to have the first and second
end walls 31a, 31b upwardly and downwardly oriented in the vertical
direction.
[0166] The PTO shaft 51 is supported by the pump case 530 so as to
extend substantially parallel to the first pump shaft 10a, and has
a lower extension, which extends downwards from the pump case 430.
In this embodiment, the lower extension of the PTO shaft 51 is
operatively connected to the working unit 140 via the belt
transmission mechanism 176.
[0167] In the thus arranged sixth embodiment, the same effects as
those of the fourth and fifth embodiments can be produced. While
the PTO shaft 51 is arranged so as to extend in the vertical
direction in this embodiment, it is a matter of course that the PTO
shaft 51 can be arranged so as to extend in the fore and aft
direction of the vehicle. In this arrangement, the
direction-changing power transmission mechanism 460 as described in
the third embodiment is provided.
[0168] In this embodiment, the output shaft of the driving source
150 and the first pump shaft 10a are arranged substantially along
the longitudinal center axis of the vehicle (see FIG. 25B).
Alternative to this, the PTO shaft 51 may be arranged substantially
in the middle of the width of the vehicle.
Seventh Embodiment
[0169] The description will be made for the seventh embodiment of
the present invention with reference to the accompanied drawings.
FIG. 27 is a plan view of a lawn mower 100G, to which a pump unit 7
of this embodiment has been applied. FIG. 28 is a plan view in
horizontal cross section of the pump unit 7 according to this
embodiment. In the following description, corresponding or
identical parts to those of the aforementioned embodiments have
been given the same reference characters to omit a detailed
description thereof.
[0170] The pump unit 7 of this embodiment has been conceived based
upon the concept of integral connection between the pump unit and
the driving source as described in the second embodiment, which is
applied to the pump unit arrangement in each of the fourth to sixth
embodiments.
[0171] With the thus arranged pump unit 7, the same effects as
those in the second embodiment, as well as the same effects as
those in the fourth and fifth embodiments can be produced. While
this embodiment has been described by taking for example the case
where the PTO shaft 51 is arranged so as to be substantially
parallel to the first pump shaft 10a, a PTO shaft 451, which
extends substantially orthogonal to the first pump shaft 10a, may
be provided.
[0172] Further, this embodiment has been described by taking for
example the case where the pump unit is integrally connected to the
driving source 150 of the horizontal type. However, it is a matter
of course that the pump unit is integrally connected to the driving
source 150' of the vertical type.
[0173] This specification is by no means intended to restrict the
present invention to the preferred embodiments set forth therein.
Various modifications to the pump unit, as well as the working
vehicle as described herein, may be made by those skilled in the
art without departing from the spirit and scope of the present
invention as defined in the appended claims.
* * * * *