U.S. patent application number 11/961248 was filed with the patent office on 2008-06-26 for multiple pump unit and vehicle with multiple pump unit.
This patent application is currently assigned to KANZAKI KOKYUKOKI MFG. CO., LTD.. Invention is credited to Norihiro ISHII, Yoshitaka ISHIMARU.
Application Number | 20080152517 11/961248 |
Document ID | / |
Family ID | 39543062 |
Filed Date | 2008-06-26 |
United States Patent
Application |
20080152517 |
Kind Code |
A1 |
ISHII; Norihiro ; et
al. |
June 26, 2008 |
MULTIPLE PUMP UNIT AND VEHICLE WITH MULTIPLE PUMP UNIT
Abstract
A multiple pump unit is used for operating a plurality of
actuators, and includes a plurality of pump shafts and a plurality
of hydraulic pumps. The plurality of pump shafts is driven by an
electric motor. The plurality of hydraulic pumps is driven by the
plurality of pump shafts. Pressurized oil for operating the
plurality of actuators is fed out from the plurality of hydraulic
pumps.
Inventors: |
ISHII; Norihiro; (Hyogo,
JP) ; ISHIMARU; Yoshitaka; (Hyogo, JP) |
Correspondence
Address: |
CANTOR COLBURN, LLP
20 Church Street, 22nd Floor
Hartford
CT
06103
US
|
Assignee: |
KANZAKI KOKYUKOKI MFG. CO.,
LTD.
Hyogo
JP
|
Family ID: |
39543062 |
Appl. No.: |
11/961248 |
Filed: |
December 20, 2007 |
Current U.S.
Class: |
417/423.5 ;
417/231 |
Current CPC
Class: |
Y02T 10/6217 20130101;
F04B 1/22 20130101; Y02T 10/62 20130101; B60Y 2200/223 20130101;
F04B 23/06 20130101; B60K 17/10 20130101; F16H 61/44 20130101; F04B
27/0895 20130101; F04B 17/03 20130101; A01D 69/03 20130101; B60K
6/46 20130101; A01D 69/02 20130101 |
Class at
Publication: |
417/423.5 ;
417/231 |
International
Class: |
F04B 17/03 20060101
F04B017/03 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 26, 2006 |
JP |
JP2006-348759 |
Claims
1. A multiple pump unit used for operating a plurality of
actuators, comprising: a plurality of pump shafts driven by an
electric motor; and a plurality of hydraulic pumps driven by the
respective plurality of pump shafts, wherein pressurized oil for
operating the plurality of actuators is fed out from the plurality
of hydraulic pumps.
2. The multiple pump unit according to claim 1, wherein at least
any one of the plurality of hydraulic pumps is a double port pump
provided with a plurality of discharge ports in correspondence with
one pump shaft, and the pressurized oil for operating the plurality
of actuators is fed out from the plurality of discharge ports of
the double port pump.
3. The multiple pump unit according to claim 1, further comprising:
a casing housing the plurality of hydraulic pumps, and rotatably
supporting a rotary shaft of the electric motor and the plurality
of hydraulic pump shafts; and a PTO shaft rotatably supported by
the casing, wherein the rotary shaft of the electric motor and the
plurality of hydraulic pump shafts are operationally connected, and
power transmission is made selectively possible between the rotary
shaft of the electric motor and the PTO shaft by a clutch
mechanism.
4. The multiple pump unit according to claim 3, further comprising:
a PTO shaft side pulley fixed to the PTO shaft projecting from the
casing.
5. The multiple pump unit according to claim 1, wherein a cooling
fan is fixed to at least one of a rotary shaft of the electric
motor or a hydraulic pump shaft among the plurality of hydraulic
pumps.
6. The multiple pump unit according to claim 5, further comprising:
a casing housing the plurality of hydraulic pumps; and a cooling
air guide part fixed to an outer side of the casing and guiding
cooling air generated by the cooling fan along the outer side of
the casing.
7. A vehicle with a multiple pump unit, comprising: the multiple
pump unit according to claim 1; a secondary battery or a fuel cell
supplying electric power to the electric motor; and electric power
supply state selecting unit selecting whether to supply electric
power to the electric motor from the secondary battery or the fuel
cell, or to shut off the supply of the electric power to the
electric motor from the secondary battery or the fuel cell.
8. The vehicle with the multiple pump unit according to claim 7,
comprising: a working machine supported by a vehicle body; and a
working machine side pulley operationally connected to the working
machine, wherein the multiple pump unit is the multiple pump unit
according to claim 4, and a belt is provided between the PTO shaft
side pulley and the working machine side pulley.
9. The vehicle with the multiple pump unit according to claim 7,
wherein the plurality of actuators driven by the pressurized oil
from the multiple pump unit are two wheel-driving hydraulic
motors.
10. The vehicle with the multiple pump unit according to claim 7,
further comprising: a generator driven by an engine, wherein
electric power generated by the generator is supplied to the
electric motor via the secondary battery or directly.
11. The vehicle with the multiple pump unit according to claim 7,
further comprising: an engine side pulley capable of being
selectively connected to an output shaft of an engine by a clutch;
a working machine supported by a vehicle body; and a working
machine side pulley operationally connected to the working machine,
wherein a belt is provided between the engine side pulley and the
working machine side pulley.
12. The vehicle with the multiple pump unit according to claim 7,
wherein a plurality of actuators driven by the pressurized oil from
the multiple pump unit are each any of a working machine raising
and lowering cylinder device raising and lowering a working
machine, a working machine drive device driving the working
machine, and a working machine tilting cylinder device tilting to
displace the working machine, and electric power is supplied to a
wheel-driving electric motor from any of the secondary battery, the
fuel cell and a generator to drive the wheel-driving electric
motor.
13. The vehicle with the multiple pump unit according to claim 7,
further comprising: a charge pump provided to replenish at least
any one of the plurality of hydraulic pumps with pressurized oil.
Description
PRIORITY INFORMATION
[0001] This application claims the benefit of priority from prior
Japanese Patent Application No. 2006-348759, filed in Japan on Dec.
26, 2006, the entire contents of which are incorporated herein by
reference.
BACKGROUND
[0002] 1. Technical Field
[0003] The present invention generally relates to a multiple pump
unit used for operating a plurality of actuators, and to a vehicle
with such a multiple pump unit.
[0004] 2. Related Art
[0005] Hydraulic pumps have been conventionally used for various
purposes. For example, work vehicles such as a lawn mower vehicles,
tractors, or trucks drive a hydraulic pump with an engine, and the
hydraulic pressure produced is used to rotate two wheel-driving
hydraulic motors, which are a plurality of actuators, which in turn
drive the two front or rear wheels.
[0006] Further, a work vehicle such as a lawn mower vehicle or a
tractor is sometimes used to drive working machines such as a mower
or a cultivator, and to raise and lower the machine. As a result,
the concept of creating a dual pump unit by combining two hydraulic
pumps and driving the machine via a PTO (power take off) shaft
capable of taking out power from the drive source was proposed.
[0007] For example, Japanese Patent Laid-Open Publication No.
2003-306052 discloses a pump unit including a PTO shaft and two
hydraulic pump bodies. In the disclosed configuration, a first pump
shaft and a second pump shaft are operationally connected to an
input shaft connected to a drive source, and power transmission
between the input shaft and the PTO shaft, and shutoff of the power
transmission are made switchable by a hydraulic clutch mechanism
provided between the input shaft and the PTO shaft. The first pump
shaft drives a first hydraulic pump body, and pressurizes the oil
supplied into the first hydraulic pump body from an oil supply port
to discharge the oil from a discharge port. The second pump shaft
drives a second hydraulic pump body, and pressurizes the oil
supplied into the second hydraulic pump body from another oil
supply port to discharge the oil from another discharge port.
[0008] A first hydraulic motor and a second hydraulic motor are
respectively driven by the oil discharged from the first hydraulic
pump body and the second hydraulic pump body, and wheels
corresponding to them are rotated. Further, the PTO shaft and the
working machine are connected by a transmission shaft.
[0009] In the case of the pump unit disclosed in Japanese Patent
Laid-Open Publication No. 2003-306052, when the drive source is an
engine, the engine must be driven whenever the wheels or an
attachment are driven. Therefore, it still has room for improvement
in the aspect of enhancement of quietness. For example, in the
working vehicle including the pump unit disclosed in Japanese
Patent Laid-Open Publication No. 2003-306052, when the drive source
is an engine, the engine is always driven, and therefore use of the
working vehicle in an environment where quietness is desired, such
as an area near a residential district, is likely to be difficult
due to the noise generated by the engine.
[0010] Further, although it has been conventionally conceived of
driving one pump with one electric motor, with such a configuration
the range of use is small, and usability is low. For example, when
two wheels at both left and right sides are driven with one pump,
independent control of the wheels is difficult, and it is likely to
be difficult to make the turning radius small.
SUMMARY
[0011] It is an advantage of the present invention to provide a
structure usable for many purposes and providing superior
quietness, in a multiple pump unit and a vehicle with the multiple
pump unit.
[0012] A multiple pump unit according to the present invention may
be configured as a multiple pump unit used for operating a
plurality of actuators, characterized by including a plurality of
pump shafts driven by an electric motor, and a plurality of
hydraulic pumps driven by the respective plurality of pump shafts,
wherein pressurized oil for operating the plurality of actuators is
fed out from the plurality of hydraulic pumps.
[0013] According to this constitution, a plurality of pump shafts
which drive a plurality of hydraulic pumps are driven by the
electric motor, and the pressurized oil for operating a plurality
of actuators is fed out from the plurality of hydraulic pumps.
Therefore, because electric power can be supplied to a secondary
battery or the like from a generator or the like driven by an
engine, and this electric power can then be supplied to the
electric motor from the secondary battery or the like, the engine
does not have to be always operated for operating the plurality of
actuators. Therefore, the structure capable of providing very quiet
operation is obtained. In addition, because the multiple pump unit
can be used for a larger number of purposes, usability can be
enhanced compared to configurations in which the electric motor
drives only one pump shaft constituting a hydraulic pump.
[0014] Further, preferably, at least any one of the plurality of
hydraulic pumps is a double port pump provided with a plurality of
discharge ports in correspondence with one pump shaft, and the
pressurized oil for operating the plurality of actuators is fed out
from the plurality of discharge ports of the double port pump.
[0015] With this constitution, the pressurized oil for operating a
larger number of actuators is fed out from the plurality of
hydraulic pumps, and a larger number of actuators can be operated.
Therefore, usability can be further enhanced.
[0016] Further, more preferably, a casing housing the plurality of
hydraulic pumps and rotatably supporting a rotary shaft of the
electric motor and the plurality of hydraulic pump shafts, and a
PTO shaft rotatably supported by the casing are included, the
rotary shaft of the electric motor and the plurality of hydraulic
pump shafts are operationally connected, and power transmission is
made selectively possible between the rotary shaft of the electric
motor and the PTO shaft by a clutch mechanism.
[0017] According to this constitution, irrespective of the rotation
of the electric motor, operation and non-operation of the working
machine or the like operationally connected to the PTO shaft can be
selected by the clutch mechanism, and usability can be further
enhanced.
[0018] Further, more preferably, a PTO shaft side pulley fixed to
the PTO shaft projecting from the casing is included.
[0019] Further, more preferably, a cooling fan is fixed to at least
one of a rotary shaft of the electric motor or a hydraulic pump
shaft among the plurality of hydraulic pumps
[0020] With this constitution, the equipment including the electric
motor and the plurality of hydraulic pumps can be easily cooled,
making it easier to further enhance performance.
[0021] Further, more preferably, a casing housing the plurality of
hydraulic pumps, and a cooling air guide part fixed to an outer
side of the casing and guiding cooling air generated by the cooling
fan along the outer side of the casing are included.
[0022] With this constitution, the casing can be easily cooled by
the cooling air, making it still easier to further enhance
performance.
[0023] Further, a vehicle with a multiple pump unit according to
the present invention includes the above described multiple pump
unit, a secondary battery or a fuel cell supplying electric power
to the electric motor, and electric power supply state selecting
unit selecting whether to supply electric power to the electric
motor from the secondary battery or the fuel cell, or to shut off
the supply of the electric power to the electric motor from the
secondary battery or the fuel cell.
[0024] Further, more preferably, a working machine supported by a
vehicle body, and a working machine side pulley operationally
connected to the working machine are included, the multiple pump
unit includes a casing housing the plurality of hydraulic pumps,
and rotatably supporting a rotary shaft of the electric motor and
the plurality of hydraulic pump shafts, and a PTO shaft rotatably
supported by the casing, the rotary shaft of the electric motor and
the plurality of hydraulic pump shafts are operationally connected,
power transmission is made selectively possible between the rotary
shaft of the electric motor and the PTO shaft by a clutch
mechanism, a PTO shaft side pulley fixed to the PTO shaft projected
from the casing is included, and a belt is provided between the PTO
shaft side pulley and the working machine side pulley.
[0025] Further, more preferably, the plurality of actuators driven
by the pressurized oil from the multiple pump unit are two
wheel-driving hydraulic motors.
[0026] Further, more preferably, a generator driven by an engine is
included, and electric power generated by the generator is supplied
to the electric motor via the secondary battery or directly.
[0027] Further, more preferably, an engine side pulley capable of
being selectively connected to an output shaft of an engine by a
clutch, and a working machine supported by a vehicle body, and a
working machine side pulley operationally connected to the working
machine are included, and a belt is provided between the engine
side pulley and the working machine side pulley.
[0028] Further, more preferably, a plurality of actuators driven by
the pressurized oil from the multiple pump unit are each any of a
working machine raising and lowering cylinder device raising and
lowering a working machine, a working machine drive device driving
the working machine, and a working machine tilting cylinder device
tilting to displace the working machine, and electric power is
supplied to a wheel-driving electric motor from any of the
secondary battery, the fuel cell, and a generator to drive the
wheel-driving electric motor.
[0029] Further, more preferably, a charge pump provided to
replenish at least any one of the plurality of hydraulic pumps with
pressurized oil is included.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1a is a diagram showing a basic constitution of a
vehicle with a multiple pump unit of a first embodiment according
to the present invention;
[0031] FIG. 1b is a diagram showing a basic constitution of a
vehicle with a multiple pump unit of a second embodiment according
to the present invention;
[0032] FIG. 1c is a diagram showing a basic constitution of a
vehicle with a multiple pump unit of a seventh embodiment according
to the present invention;
[0033] FIG. 2 is a schematic illustration showing a constitution of
a working vehicle that is the vehicle with the multiple pump unit
of the first embodiment;
[0034] FIG. 3 is a schematic sectional view taken along the line
A-A in FIG. 2;
[0035] FIG. 4 is a diagram showing a hydraulic circuit used in the
first embodiment;
[0036] FIG. 5 is a sectional view showing a dual pump unit that is
the multiple pump unit of the first embodiment;
[0037] FIG. 6 is a schematic illustration showing a constitution of
a working vehicle that is the vehicle with the multiple pump unit
of the second embodiment according to the present invention;
[0038] FIG. 7 is a schematic sectional view taken along the line
B-B in FIG. 6;
[0039] FIG. 8 is a diagram showing a hydraulic circuit used in the
second embodiment;
[0040] FIG. 9 is a sectional view showing a dual pump unit that is
the multiple pump unit of the second embodiment;
[0041] FIG. 10 is a sectional view showing a dual pump unit that is
a multiple pump unit of a third embodiment according to the present
invention;
[0042] FIG. 11 is a sectional view showing a dual pump unit that is
a multiple pump unit of a fourth embodiment of the present
invention;
[0043] FIG. 12 is a sectional view showing a dual pump unit that is
a multiple pump unit of a fifth embodiment of the present
invention;
[0044] FIG. 13 is a sectional view showing a dual pump unit that is
a multiple pump unit of a sixth embodiment of the present
invention;
[0045] FIG. 14 is a schematic illustration showing a constitution
of a working vehicle that is the vehicle with the multiple pump
unit of the seventh embodiment of the present invention;
[0046] FIG. 15a is a diagram showing a basic constitution of a
vehicle with a multiple pump unit of an eighth embodiment of the
present invention;
[0047] FIG. 15b is a diagram showing a basic constitution of a
vehicle with a multiple pump unit of a ninth embodiment of the
present invention;
[0048] FIG. 16 is a sectional view showing a drive device portion
of a wheel on one side in a working vehicle that is a vehicle with
a multiple pump unit of a tenth embodiment of the present
invention;
[0049] FIG. 17 is a sectional view similar to FIG. 16, in a working
vehicle that is a vehicle with a multiple pump unit of an eleventh
embodiment of the present invention;
[0050] FIG. 18 is a view corresponding to an enlarged section of a
part C in FIG. 16, in a working vehicle that is a vehicle with a
multiple pump unit of a twelfth embodiment of the present
invention;
[0051] FIG. 19 is a view corresponding to an enlarged section of a
part D in FIG. 16, in a working vehicle that is a vehicle with a
multiple pump unit of a thirteenth embodiment of the present
invention;
[0052] FIG. 20 is a diagram showing a basic constitution and a
hydraulic circuit of a working vehicle that is a vehicle with a
multiple pump unit of a fourteenth embodiment of the present
invention;
[0053] FIG. 21 is a diagram showing a basic constitution and a
hydraulic circuit of a working vehicle that is a vehicle with a
multiple pump unit of a fifteenth embodiment of the present
invention;
[0054] FIG. 22 is a diagram showing a basic constitution and a
hydraulic circuit of a working vehicle that is a vehicle with a
multiple pump unit of a first reference example relating to the
present invention;
[0055] FIG. 23 is a diagram showing a basic constitution and a
hydraulic circuit of a working vehicle that is a vehicle with a
multiple pump unit of a second reference example of the present
invention;
[0056] FIG. 24 is a diagram showing a basic constitution and a
hydraulic circuit of a working vehicle that is a vehicle with a
multiple pump unit of a sixteenth embodiment of the present
invention; and
[0057] FIG. 25 is a diagram showing a basic constitution and a
hydraulic circuit of a working vehicle that is a vehicle with a
multiple pump unit of a third reference example relating to the
present invention.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
First Embodiment of the Invention
[0058] Hereinafter, embodiments of the present invention will be
described in detail while referring to the drawings. FIG. 1a is a
block diagram showing a basic constitution of this embodiment, FIG.
1b is a block diagram showing a basic constitution of a second
embodiment which will be described later, and FIG. 1c is a block
diagram showing a basic constitution of a seventh embodiment which
will be described later. FIG. 2 is a schematic side view of a
vehicle with a multiple pump unit of this embodiment configured as
a lawn mower vehicle, and FIG. 3 is a schematic sectional view
taken along the line A-A in FIG. 2. FIG. 4 is a diagram of a
hydraulic circuit used in this embodiment, and FIG. 5 is a
sectional view showing the multiple pump unit of this
embodiment.
[0059] First, based on FIG. 1a, the basic constitution of the
vehicle with the multiple pump unit of this embodiment will be
described. The basic constitution of the vehicle with the multiple
pump unit of this embodiment includes an engine 10, a generator 12
connected to the engine 10 in such a manner that it is capable of
transmitting power and being driven by the engine 10, a battery 14
that is a secondary battery supplied with electric power from the
generator 12, a dual pump unit 16 that is the multiple pump unit,
two wheel-driving hydraulic motors 18 and 20 that are wheel-driving
hydraulic motors, a controller 22 that is a control unit and a
working machine 24. The controller 22 is, for example, a computer
such as an ECU (Electronic Control Unit) including a CPU.
[0060] The dual pump unit 16 is used for operating the two
wheel-driving hydraulic motors 18 and 20 via a hydraulic circuit,
and includes an electric motor 26, and a dual pump (DUP) 28 having
two hydraulic pumps. The electric motor 26 is supplied with
electric power from the battery 14 and drives two pump shafts
constituting the dual pump 28. Because the two hydraulic pumps are
driven by the two pump shafts, pressurized oil is discharged from
the two hydraulic pumps and the discharged pressurized oil operates
the two wheel-driving hydraulic motors 18 and 20 provided at the
left and right of the vehicle via the hydraulic circuit.
Specifically, the hydraulic motors 18 and 20 are driven.
[0061] Further, the power of the electric motor 26 is transmitted
to the PTO shaft from the dual pump unit 16, then transmitted to a
pulley fixed to a driven shaft for driving the working machine 24
via a pulley fixed to the PTO shaft and a belt, and the working
machine 24 is thus driven.
[0062] Further, the controller 22 sends a control signal to a DC/DC
converter, not shown, connected to the battery 14, and controls the
electric power taken out from the battery 14. Further, the
controller 22 sends a control signal to an inverter not shown
connected to the electric motor 26, and controls the output of the
electric motor 26. FIGS. 1a, 1b and 1c show representation such
that control signals are transferred to and from the battery 14 and
the controller 22, and to and from the electric motor 26 and the
controller 22 (further to and from the battery 14 and the wheel
driving electric motors 142 and 144 in FIG. 1c), but actually,
control signals are transferred to and from the DC/DC converter
connected to the battery 14 or the inverter connected to the
electric motor 26 (further, the wheel driving electric motors 142
and 144 in FIG. 1c) and the controller 22. The controller 22 has
electric power supply state selecting unit which selects whether to
supply electric power to the electric motor 26 from the battery 14
or to shut off the supply of the electric power to the electric
motor 26 from the battery 14.
[0063] Next, based on FIGS. 2 and 3, a working vehicle 30 that is a
vehicle with a multiple pump unit will be described in detail.
Hereinafter, an example wherein the present invention is applied to
a lawn mower vehicle will be described as an example of a vehicle
with the multiple pump unit. In addition to a working vehicle which
conducts, for example, work to a ground, that is, ground work, the
vehicle with the multiple pump unit may be any vehicle, as long as
the vehicle generally drives wheels and the like using a hydraulic
motor that is an actuator by using a hydraulic pump. A vehicle
having a cultivator, a truck having a deck tilting device, a
vehicle having a seedling transplanting machine, a vehicle having a
bulldozer attachment, a vehicle having an attached digger and the
like may all also be adopted in addition to a lawn mower vehicle
having a mower as shown in FIGS. 2 and 3, for example. For example,
in the case of a truck, the deck tilting device or the like
corresponds to an actuator. Further, the actuator may be a
hydraulic cylinder device constituting a power steering
apparatus.
[0064] FIGS. 2 and 3 show the constitution of the working vehicle
30. In the working vehicle 30, two wheels (rear wheels in the
drawing) 32 are made drivable by a first hydraulic motor 34 and a
second hydraulic motor 36 (FIG. 3) that are the two hydraulic
motors. The working vehicle 30 is a mowing vehicle which includes a
mower (lawnmower attachment) 38 corresponding to the working
machine 24 (FIG. 1a), and also travels along the ground propelled
by the two wheels 32. Operation parts such as an operation lever 40
for operating the mower 38, accelerates and brakes the working
vehicle 30 are provided near a driver's seat in which an operator
sits.
[0065] The working vehicle 30 includes a frame 42 constituting a
vehicle body, the engine 10 which is an on-vehicle internal
combustion engine supported by the frame 42, the generator 12 which
is operationally connected to an output shaft of the engine 10
(specifically, has its drive shaft operationally connected to the
output shaft), the battery 14 (see FIGS. 1a, 1b and 1c, not shown
in FIGS. 2 and 3) which is supplied with electric power from the
generator 12 and stores the electric power, and the dual pump unit
16 which has the electric motor 26 driven by the electric power
supplied from the battery 14. For example, the output shaft of the
engine 10 may face downward and the drive shaft constituting the
generator 12 may be connected to the lower end portion of the
output shaft, or the output shaft of the engine 10 and the drive
shaft of the generator 12 may be integrally constituted by a common
shaft. A drive pulley is fixed to an end portion of the output
shaft of the engine 10, and the generator 12 can be driven by the
engine 10 via the drive pulley, a belt, and a driven pulley fixed
to the drive shaft of the generator 12. The battery 14 and the dual
pump unit 16 may be supported at the frame 42 directly or via other
members.
[0066] The two wheels 32 which are rear wheels are supported at an
intermediate portion in the longitudinal direction of the frame 42,
and a pair of left and right casters 43 are supported at portions
separated to the left and the right at a front end portion of the
frame 42. The mower 38 is provided between the caster 43 and the
wheels 32 with respect to the longitudinal direction of the frame
42. The mower 38 is supported at the frame 42 to be adjustable in
the height direction. Further, the mower 38 is provided with a
discharge duct 47 for discharging cut grass rearward. The discharge
duct 47 extends rearward through a space between the first
hydraulic motor 34 and the second hydraulic motor 36 provided to
correspond to the two wheels 32.
[0067] The dual pump unit 16 includes a casing 44, the electric
motor 26 (FIG. 1a), the dual pump 28 (FIG. 1a), and a PTO shaft 45,
which are respectively provided in the casing 44. The dual pump 28
includes a first hydraulic pump and a second hydraulic pump which
will be described later. An output shaft of the electric motor 26
is operationally connected to a first pump shaft constituting the
first hydraulic pump and a second pump shaft constituting the
second hydraulic pump. The pressurized oil discharged from the
first hydraulic pump and the second hydraulic pump by driving of
the first hydraulic pump and the second hydraulic pump is supplied
to the first hydraulic motor 34 and the second hydraulic motor 36
via a hydraulic pipe line 46 (FIG. 3) constituting the hydraulic
circuit, such that the wheels 32 are driven in conjunction with the
respective hydraulic motors 34 and 36. The first hydraulic motor 34
and the second hydraulic motor 36 correspond to the wheel-driving
hydraulic motors 18 and 20 (FIG. 1a), respectively.
[0068] Pair of operation levers 40 are provided to the left and
right of the driver's seat, and are used to adjust the hydraulic
pressure which is supplied to each of the hydraulic motors 34 and
36 and adjust the drive force of the two left and right wheels 32
independently at the left and the right. In the example shown in
the drawings, only the rear wheels of the working vehicle 30 are
driven, but a hydraulic motor may be provided to correspond to each
of four wheels in total, that is, two wheels for each of both left
and right sides so that the two hydraulic motors of one of the left
and right sides are driven by the pressurized oil discharged from
one hydraulic pump, and the two hydraulic motors corresponding to
the two wheels at the other one of the left and right sides are
driven by the pressurized oil discharged from the other hydraulic
pump.
[0069] Further, the dual pump unit 16 is capable of transmitting
the power of the electric motor 26 to the PTO shaft 45 via a gear
mechanism and a hydraulic clutch mechanism which will be described
later. A lower end portion of the PTO shaft 45 is projected
downward from a lower side of the casing 44, and a PTO shaft side
pulley 48 is fixed to it. A belt 52 is provided between the PTO
shaft side pulley 48 and a working machine side pulley 50 fixed to
the driven shaft of the mower 38. Specifically, the working machine
side pulley 50 is operationally connected to the mower 38. By such
a constitution, the mower 38 is made drivable by the power of the
electric motor 26.
[0070] FIG. 4 is a diagram showing the hydraulic circuit for
explaining the flow of the pressurized oil between a first
hydraulic pump 54 and a second hydraulic pump 56 which constitute
the dual pump 28, and the first hydraulic motor 34 and the second
hydraulic motor 36 which drive the wheels 32. The engine 10 drives
the output shaft, and thereby, the generator 12 is driven via the
output shaft. The electric power generated by the generator 12 is
supplied to the battery 14, and the electric motor 26 is driven by
the electric power from the battery 14. The DC/DC converter (not
shown) connected to the battery 14 and an inverter (not shown)
connected to the electric motor 26 are controlled by the controller
22.
[0071] In the dual pump unit 16, the first pump shaft and the
second pump shaft, which will be described later, are operationally
connected to the output shaft of the electric motor 26.
Specifically, the output shaft of the electric motor 26 and the
first pump shaft are constituted of a common drive shaft 58, and
the output shaft of the electric motor 26 and a second pump shaft
60 are connected to be capable of transmitting power by a gear
mechanism 62. As shown in FIG. 5 which will be described later, an
output shaft 64 of the electric motor 26 and a first pump shaft 66
can be connected to be capable of transmitting power by the gear
mechanism 62.
[0072] Returning again to FIG. 4, the first hydraulic pump 54 is
driven by the drive shaft 58 which is the first pump shaft, and the
second hydraulic pump 56 is driven by the second pump shaft 60.
Further, a charge pump 68 is made drivable by the drive shaft 58.
Thereby, the electric motor 26, the first hydraulic pump 54, the
charge pump 68 and the second hydraulic pump 56 are driven at the
same time.
[0073] The charge pump 68 has the function of replenishing an oil
deficit caused as a result of oil leakage which is caused by the
oil circulating in the hydraulic circuit and the like. More
specifically, the charge pump 68 sucks oil from an external tank 72
through a filter 70, pressurizes the oil, supplies the oil to a
hydraulic path at a low pressure side through a check valve 74, and
supplies part of the oil to a hydraulic path at a high pressure
side through another check valve 74 as necessary. Specifically, a
discharge side of the charge pump 68 branches into a charge line
220 and a working oil line 222 from a main pressurized oil line 216
via a pressure reducing valve 218 for setting charge pressure. A
relief valve 76 has a function of maintaining the hydraulic
pressure of the main pressurized oil line 216. The external tank 72
is connected to the casing 44 which is a pump case, so that oil is
supplied to the tank 72 from an oil reservoir in the casing 44. The
first hydraulic pump 54 and the second hydraulic pump 56 are housed
in the casing 44.
[0074] The pressurized oil discharged from the first hydraulic pump
54 is supplied to the first hydraulic motor 34 corresponding to the
wheel 32 at one side (upper side in FIG. 4) of the left and right
wheels 32, and drives the wheel 32 at the one side via a planetary
gear mechanism 78. The first hydraulic pump 54 has a function of
causing the pressurized oil to flow by reversing the pressure
increasing side and the pressure decreasing side.
[0075] Further, the pressurized oil discharged from the second
hydraulic pump 56 is supplied to the second hydraulic motor 36
corresponding to the wheel 32 at the other side (lower side of FIG.
4) of the left and right wheels, and drives the wheel 32 at the
other side via the planetary gear mechanism 78. The second
hydraulic pump 56 also has a function of causing the pressurized
oil to flow by reversing the pressure increasing side and the
pressure decreasing side as the first hydraulic pump 54.
[0076] The charge line 220 and the hydraulic circuit including the
second hydraulic pump 56 are connected by a connecting line 80. The
oil supplied from the connecting line 80 is supplied to a low
pressure side of the hydraulic path including the second hydraulic
pump 56 through a check valve 82, and part of it is supplied to a
high pressure side of the hydraulic path including the second
hydraulic pump 56 through another check valve 82. Oil reservoirs in
the casing respectively constituting the first hydraulic motor 34
and the second hydraulic motor 36 are connected to the tank 72.
[0077] Further, bypass valves 84 are provided at bypass paths
disposed in parallel with respect to the flow of the pressurized
oil for the respective hydraulic pumps 54 and 56, and, by opening
the bypass valves 84, the supply of the pressurized oil to the
hydraulic motors 34 and 36 corresponding to the opened bypass
valves 84 from the respective hydraulic pumps 54 and 56 is stopped.
Thereby, the load on the hydraulic motors 34 and 36 can be removed
when, for example, it is desired to push or otherwise forcibly move
the working vehicle 30 when the electric motor is stopped. Such
bypass valves 84 can be made manually operated valves.
[0078] Further, the second pump shaft 60 and a drive side member 86
are operationally connected by a gear mechanism 88, and a hydraulic
clutch mechanism 90 is provided between the drive side member 86
and the PTO shaft 45. Thus, power transmission between the drive
side member 86 and the PTO shaft 45 is selectively made possible by
the hydraulic clutch mechanism 90. The pressurized oil from the
main pressurized oil line 216 is allowed to be supplied to the
hydraulic clutch mechanism 90 by the working oil line 222. Though
not illustrated, a hydraulic path may be branched from the charge
line 220 or the main pressurized oil line 216, and by the
pressurized oil from the branched hydraulic path, the actuator,
such as a cylinder for raising and lowering the mower 38 (see FIG.
2), can be operated.
[0079] Next, a specific example structure of the dual pump unit 16
which is the multiple pump unit of this embodiment will be
described in more detail by referring to FIG. 5. The parts
equivalent to the parts described in FIGS. 1a to 4 will be assigned
the same reference numerals and characters, and their description
will not be repeated. In the dual pump unit 16, the first pump
shaft 66 constituting the first hydraulic pump 54, the second pump
shaft 60 constituting the second hydraulic pump 56, the output
shaft 64 of the electric motor 26, and the PTO shaft 45 are
rotatably supported on the casing 44 so as to be parallel with each
other, and the first hydraulic pump 54 and the second hydraulic
pump 56 are housed in the casing 44.
[0080] As a gear part fixed to the output shaft 64 of the electric
motor 26 is disposed between the first pump shaft 66 and the second
pump shaft 60, the first pump shaft 66 and the second pump shaft 60
and the output shaft 64 of the electric motor 26 are operationally
connected by the gear mechanism 62. The output shaft 64 of the
electric motor 26 is extended to the side opposite from the first
pump shaft 66 and the second pump shaft 60. A cooling fan 96 is
fixed to a portion that is one end portion (upper end portion in
FIG. 5) of the output shaft 64 and is projected outside the casing
44.
[0081] The first hydraulic pump 54 and the second hydraulic pump 56
are both variable displacement axial piston pumps, and each
includes a plurality of piston cylinder mechanisms 98 disposed
around the first pump shaft 66 (or the second pump shaft 60), and a
movable swash plate mechanism 100 which restricts a stroke length
of each of the pistons when a plurality of piston cylinder
mechanisms 98 rotate around the first pump shaft 66 (or the second
pump shaft 60). The movable swash plate mechanism 100 controls the
degree and direction of the inclination with respect to the first
pump shaft 66 (or the second pump shaft 60) by a swash plate
control shaft, whereby the amount of oil sucked and discharged by
the piston cylinder mechanism 98 is controlled. By reversing the
direction of the swash plate, the pressure increasing side and the
pressure decreasing side are switched with one another. The
pressurized oil discharged from the first hydraulic pump 54 and the
second hydraulic pump 56 as above is supplied to the first
hydraulic motor 34 and the second hydraulic motor 36 (FIG. 4)
respectively via the hydraulic circuit, and the respective
hydraulic motors 34 and 36 are driven to rotate the corresponding
wheels 32 (FIG. 4).
[0082] As shown in FIG. 5, a charge pump body 102 is fixed to a
side of the casing 44 opposite from the portion supporting the
electric motor 26. The charge pump 68 is provided inside the charge
pump body 102, and the charge pump 68 is driven by an end portion
of the first pump shaft 66 constituting the first hydraulic pump
54.
[0083] Meanwhile, the drive side member 86 is supported on an
outside diameter side of an intermediate portion of the PTO shaft
45 in such a manner that the components are rotatable relative to
each other, and the hydraulic clutch mechanism 90 is provided
between the drive side member 86 and the PTO shaft 45. The
hydraulic clutch mechanism 90 includes a plurality of drive side
friction plates which are supported around a lower side portion of
the drive side member 86 to be incapable of relative rotation and
capable of displacement in an axial direction, and includes a
plurality of driven side friction plates which are supported at a
driven side member 104 fixed to a circumference of the PTO shaft 45
to be incapable of relative rotation and capable of displacement in
the axial direction, and applies a resilient force to a member
which brings the drive side friction plates and the driven side
friction plates in pressure contact with each other in a direction
to be away from each other by biasing means 106. Further, the
hydraulic clutch mechanism 90 includes a clutch pressing moving
member 108 which receives the action of hydraulic pressure and
presses the either one of the friction plates so that the drive
side friction plates and the driven side friction plates are
engaged with each other. A gear constituting the gear mechanism 88
is integrally provided at an upper portion of the drive side member
86. The power of the second pump shaft 60 is transmitted to the
drive side member 86 by the gear mechanism 88.
[0084] In such a hydraulic clutch mechanism 90, in the state in
which the drive side friction plates and the driven side friction
plates are engaged by movement of the clutch pressing moving member
108, power transmission to the PTO shaft 45 from the output shaft
64 of the electric motor 26 is made possible, and, in a state in
which engagement of the drive side friction plates and the driven
side friction plates is released, power transmission to the PTO
shaft 45 from the output shaft 64 of the electric motor 26 is shut
off. When the PTO shaft 45 is driven, whereby the power of the PTO
shaft 45 is transmitted to the driven shaft of the mower 38 via the
PTO shaft side pulley 48, the belt 52, and the working machine side
pulley 50 (FIG. 2), the mower 38 is driven. The connection state of
the hydraulic clutch mechanism 90 is manually switchable by the
operation part such as a switch not illustrated.
[0085] In the example multiple pump unit vehicle with the multiple
pump unit of the present embodiment as above, the first pump shaft
66 (FIG. 5) or the drive shaft 58 (FIG. 4) which drives the first
hydraulic pump 54, and the second pump shaft 60 which drives the
second hydraulic pump 56 are driven by the electric motor 26, and
the pressurized oil for operating the first hydraulic motor 34 and
the second hydraulic motor 36, which are a plurality of actuators,
is fed out from the first hydraulic pump 54 and the second
hydraulic pump 56. Therefore, when electric power is supplied to
the battery 14 from the generator 12 driven by the engine 10 (FIG.
4) and the electric power is supplied to the electric motor 26 from
the battery 14 as in this embodiment, it is not always necessary to
operate the engine 10 in order to operate the hydraulic motors 34
and 36 for driving the wheels 32, which contrasts with the
structure of driving the first pump shaft 66 (FIG. 5) or the drive
shaft 58 (FIG. 4) and the second pump shaft 60 by the power of the
engine 10 without providing an electric motor. Therefore, with the
present invention, a structure capable of operating very quietly
can be obtained. Specifically, when sufficient electric power is
charged in the battery 14, the respective hydraulic motors 34 and
36 corresponding to the wheels 32 can be driven by driving the
electric motor 26 by the electric power from the battery 14 in the
state in which the engine 10 is stopped and the driving noise is
small.
[0086] In addition, the multiple pump unit can be used for a
greater number of applications and usability can be enhanced
compared to configurations in which the electric motor 26 drives
only one pump shaft constituting the hydraulic pump. In the case of
this embodiment, the different hydraulic motors 34 and 36
corresponding to the two wheels 32 can be driven by the pressurized
oil from the different hydraulic pumps 54 and 56, and the two
hydraulic motors 34 and 36 can be more effectively controlled
independently. As a result, by making the output of one of the two
hydraulic motors 34 and 36 larger than the output of the other
hydraulic motor, the working vehicle 30 can be smoothly turned
while skidding of the wheels 32 is suppressed. On the other hand,
when the two hydraulic motors 34 and 36 corresponding to the two
left and right wheels 32 are driven by the pressurized oil from one
hydraulic pump, a flow dividing valve for directing the oil into
the two hydraulic motors 34 and 36 must be provided in the
hydraulic circuit, and it has room for improvement from the aspect
of enhancement of usability.
[0087] Further, the casing 44 which houses the first hydraulic pump
54 and the second hydraulic pump 56, and rotatably supports the
output shaft 64 of the electric motor 26, the first pump shaft 66
(FIG. 5) or the drive shaft 58 (FIG. 4) and the second pump shaft
60, and the PTO shaft 45 rotatably supported by the casing 44 are
included. Further, the output shaft 64 of the electric motor 26,
and the first pump shaft 66 and the second pump shaft 60 are
operationally connected, and the power transmission is selectively
made possible between the output shaft 64 of the electric motor 26
and the PTO shaft 45 by the hydraulic clutch mechanism 90.
Therefore, irrespective of the rotation of the electric motor 26,
operation and non-operation of the mower 38 (FIG. 2) which is
operationally connected to the PTO shaft 45 can be selected by the
hydraulic clutch mechanism 90, and usability can be further
enhanced.
[0088] Because the cooling fan 96 (FIGS. 2, 3 and 5) is fixed to
the output shaft 64 of the electric motor 26, the electric motor 26
and the dual pump unit 16 including a plurality of hydraulic pumps
54 and 56 can be easily cooled, thereby making it possible to
further enhance performance.
Second Embodiment of the Invention
[0089] FIGS. 6 to 9 show a second embodiment of the present
invention. Unlike the above-described first embodiment, in this
embodiment, the mower 38, which is the working machine, is not
driven by the power of the electric motor, but by the power of the
engine 10. First, the basic constitution of a vehicle with a
multiple pump unit according to this embodiment will be described
by referring to FIG. 1b. As shown in FIG. 1b, in the case of this
embodiment, the power from the engine 10 is transmitted to the
working machine 24, so that the working machine 24 is driven
without a medium of the electric motor 26. Further, by the power of
the electric motor 26, the two pump shafts provided respectively at
the two hydraulic pumps constituting the dual pump 28 are driven.
The pressurized oil discharged from the two hydraulic pumps is
supplied to the two wheel-driving hydraulic motors 18 and 20, and
the two wheel-driving hydraulic motors 18 and 20 are driven. In
FIG. 1b, the basic constitution is otherwise the same as in the
first embodiment described with reference to FIG. 1a.
[0090] Next, FIGS. 6 and 7 show a constitution of a working vehicle
30a, which is the example vehicle with the multiple pump unit of
this embodiment. FIG. 7 is a sectional view taken along the line
B-B in FIG. 6. As shown in FIGS. 6 and 7, neither the PTO shaft 45
nor the PTO shaft side pulley 48 (see FIGS. 2 and 3) is provided at
a dual pump unit 16a. Instead, the drive shaft of the generator 12
is connected to the output shaft disposed in the vertical direction
of the engine 10 to be capable of transmitting power, and an engine
side pulley 112 is fixed to a lower end portion of a PTO shaft 45a
which can be selectively connected to the drive shaft of the
generator 12 by a clutch mechanism 110. Specifically, the engine
side pulley 112 can be selectively connected to the output shaft of
the engine 10 by the clutch mechanism 110. The clutch mechanism 110
enables manual selection of power transmission between the drive
shaft of the generator 12 and the PTO shaft 45a and shutoff of the
power transmission through operation of a component such as a
switch.
[0091] Further, the belt 52 is provided between the engine side
pulley 112 and the working machine side pulley 50 fixed to the
driven shaft of the mower 38. Specifically, the working machine
side pulley 50 is operationally connected to the mower 38. Thereby,
in the state in which the clutch mechanism 110 is connected, the
mower 38 is drivable by the power of the engine 10. The
constitution shown in FIGS. 6 and 7 is otherwise the same as that
of the first embodiment described with reference to FIGS. 2 and
3.
[0092] Next, FIG. 8 is a diagram showing a hydraulic circuit used
in this embodiment. Unlike the case of the first embodiment shown
in FIG. 4 described above, in the case of this embodiment, the PTO
shaft 45a is disposed to be selectively connectable to the drive
shaft of the generator 12 by the clutch mechanism 110 (see FIG. 6,
illustration is omitted in FIG. 8). The engine side pulley 112 is
fixed to the PTO shaft 45a, and the mower 38 (FIG. 6) is made
drivable via the engine side pulley 112, the belt 52 and the
working machine side pulley 50 (see FIG. 6) fixed to the driven
shaft of the mower 38.
[0093] Meanwhile, the dual pump unit 16a is not provided with the
PTO shaft 45, the hydraulic clutch mechanism 90, the drive side
member 86, or the gear mechanism 88 (see FIG. 4). Specifically, as
the concrete structure of the dual pump unit 16a shown in FIG. 9,
the first pump shaft 66, the second pump shaft 60 and the output
shaft 64 of the electric motor 26 are rotatably supported by the
casing 44, but the PTO shaft 45 is not provided. According to the
embodiment like this, the PTO shaft 45, the member for driving the
PTO shaft 45, and the hydraulic clutch mechanism 90 can be omitted,
and therefore, the dual pump unit 16a can be reduced in size
correspondingly.
[0094] The constitution and operation are otherwise the same as in
the first embodiment shown in FIGS. 1a and 2 to 5 described above,
and therefore the same reference numerals and characters will be
assigned to the equivalent parts and their description will not be
repeated.
Third Embodiment of the Invention
[0095] FIG. 10 shows a third embodiment of the present invention.
In the case of a dual pump unit 16b, which is the multiple pump
unit of this embodiment, in the second embodiment described by
using FIG. 9 described above, the output shaft of the electric
motor 26 and the first pump shaft of the first hydraulic pump 54
are integrally constituted of a common drive shaft 114. A gear
constituting a gear mechanism 62a is fixed to an intermediate
portion of the drive shaft 114, and the power of the drive shaft
114 is allowed to be transmitted to the second pump shaft 60 by the
gear mechanism 62a. The charge pump 68 is made drivable by an end
portion of the drive shaft 114.
[0096] In the embodiments described above, with respect to the
second embodiment shown in FIG. 9 described above, the output shaft
64 and the first pump shaft 66 (see FIG. 9) are constituted of the
common drive shaft 114, and the gear for operationally connecting
the output shaft 64 and the first pump shaft 66 is not required.
Therefore, reduction in cost by reduction of the number of
components can be achieved. Further, the width (lateral direction
in FIG. 10) of the dual pump unit 16b can be reduced, and further
reduction in size of the dual pump unit 16b can be achieved.
[0097] As the constitution and operation are otherwise the same as
in the second embodiment shown in FIGS. 6 to 9 described above,
redundant illustration and explanation are avoided by assigning the
same reference numerals and characters to the equivalent parts,
which are not described here.
Fourth Embodiment of the Invention
[0098] FIG. 11 shows a fourth embodiment of the present invention.
Unlike in the third embodiment shown in FIG. 10 described above, in
the dual pump unit 16c, which is a multiple pump unit of this
embodiment, the cooling fan 96 is not fixed to the drive shaft 114
at the electric motor 26 side, but is fixed to an end portion of
the drive shaft 114 projecting outside the casing 44 at the charge
pump 68 side.
[0099] The constitution and operation of the present embodiment are
otherwise the same as in the second embodiment shown in FIGS. 6 to
9 described above or in the third embodiment shown in FIG. 10, and,
therefore, redundant illustration and explanation is avoided by
assigning the same reference numerals and characters to the
equivalent parts, the description of which is not repeated.
Fifth Embodiment of the Invention
[0100] FIG. 12 shows a fifth embodiment of the present invention.
Unlike the third embodiment shown in FIG. 10 described above, in
the dual pump unit 16d which is a multiple pump unit of this
embodiment, the cooling fan 96 is not fixed to the end portion of
the drive shaft 114, but is fixed to an end portion of the second
pump shaft 60 projected outside the casing 44 at the charge pump 68
side (lower side in FIG. 12).
[0101] As the constitution and operation are otherwise the same as
in the second embodiment shown in FIGS. 6 to 9 described above or
in the third embodiment shown in FIG. 10, redundant illustration
and explanation will be prevented by assigning the same reference
numerals and characters to the equivalent parts, whose description
is not repeated here.
Sixth Embodiment of the Invention
[0102] FIG. 13 shows a sixth embodiment of the present invention.
In the dual pump unit 16e, which is a multiple pump unit according
to this embodiment, an outer cover 116 which is a cooling air
guiding part is fixed to an outer side of the casing 44 by a
fastening member such as a bolt as in the third embodiment shown in
FIG. 10 described above. The outer cover 116 has an inlet port 118
and an outlet port 120 for cooling air, and has a shape which
covers the entire periphery of the dual pump unit 16e. Thereby, the
cooling air generated by the cooling fan 96 flows inside the outer
cover 116 and is guided along the outer side of the casing 44.
Specifically, the cooling air, which is directed into the outer
cover 116 from the inlet port 118 in the direction of the arrow
.alpha. in FIG. 13 by the drive of the cooling fan 96, flows inside
the outer cover 116 in the direction of the arrow .beta., and
thereafter is directed out from the outlet port 120 in the
direction of the arrow .gamma..
[0103] In order to fix the outer cover 116 to the outer side of the
casing 44 by screw, in the case of the example shown in the
drawing, projection portions 122 projecting toward an outer side
with respect to the diameter direction of the drive shaft 114 are
formed at a plurality of spots of the outer surface of the casing
44, and bolts penetrating through the outer cover 116 are connected
to the projection portions 122. The dual pump unit 16e can be
disposed so that the drive shaft 114 is parallel with the
longitudinal direction with the cooling fan 96 side (upper side in
FIG. 13) oriented to the front side in the longitudinal direction
of the vehicle.
[0104] Further, a small hole 124, a first long hole 126, and a
second long hole 128 are formed in the outer cover 116 in sequence
from the end portion at the charge pump 68 side toward the end
portion at the cooling fan 96 side. A supply pipe 130 for supplying
oil to the charge pump 68 is connected to the charge pump body 102,
and the supply pipe 130 is led outside the outer cover 116 through
the small hole 124. Two supply and discharge pipes 132 for
supplying and discharging oil to and from each of the first
hydraulic pump 54 and the second hydraulic pump 56, four supply and
discharge pipes 132 in total, are connected to the casing 44, and
the four supply and discharge pipes 132 are led outside the outer
cover 116 through the first long hole 128. Further, an end portion
of a connecting pipe 134 for connecting the inside of the casing 44
and the external tank 72 (see FIG. 4) is connected to the casing
44, and the connecting pipe 134 is routed outside the outer cover
116 through the second long hole 128. A portion of a swash plate
control shaft 136 for adjusting the discharge hydraulic pressure by
the first hydraulic pump 54 and the second hydraulic pump 56, which
is led outside the casing 44, is led outside the outer cover 116
through the second long hole 128 so as to be able to adjust the
rotational angle of the swash plate control shaft 136 from outside
the outer cover 116.
[0105] According to the embodiment as above, the casing 44 which
houses the first hydraulic pump 54, the second hydraulic pump 56,
and a portion of the electric motor 26, and the outer cover 116
which is fixed to the outer side of the casing 44 to guide the
cooling air caused by the cooling fan 96 along the outer side of
the casing 44 are included. Therefore, the casing 44 can be easily
cooled by the cooling air, and performance of the first hydraulic
pump 54, the second hydraulic pump 56, and the electric motor 26
inside the casing 44 can be further and simply enhanced.
[0106] As the constitution and operation are otherwise the same as
those in the third embodiment shown in FIG. 10 described above,
redundant explanation will be avoided by assigning the same
reference numerals and characters to the equivalent parts and not
repeating their description here.
[0107] In the first embodiment shown in FIG. 5 described above, and
the second embodiment to the sixth embodiment shown in FIGS. 9 to
13, not only is one cooling fan 96 provided at one end portion of
the output shaft 64, the drive shaft 114, or the second pump shaft
60, but another cooling fan is also fixed to an end portion of the
first pump shaft 66, the second pump shaft 60, or the drive shaft
114, and the two cooling fans 96 can be provided at both sides with
the casing 44 therebetween. For example, in the third embodiment
shown in FIG. 10 described above, the cooling fans 96 can be fixed
to both the end portion of the drive shaft 114 at the electric
motor 26 side and the end portion of the drive shaft 114 at the
charge pump body 102 side. With such a constitution, the casing 44
can be cooled more efficiently by driving the two cooling fans 96.
The cooling air directed by the cooling fan 96 can be made to flow
in one direction from one end portion of the casing 44 to the other
end portion, or can be made to flow toward the center from both
sides of the casing 44 and thereafter can be blown outside with
respect to the diameter direction of the drive shaft 114 from the
center.
Seventh Embodiment of the Invention
[0108] FIG. 14 shows a seventh embodiment of the present invention.
Unlike the first embodiment shown in FIGS. 1a and 2 to 5 described
above, in this embodiment, the mower 38 which is a working machine
is made drivable by feeding the pressurized oil fed from the dual
pump to a working machine driving hydraulic motor 137 which is an
actuator and also a working machine driving device. First, a basic
constitution of a vehicle with a multiple pump unit of this
embodiment will be described with reference to FIG. 1c. As shown in
FIG. 1c, in this embodiment, the power from the engine 10 is
transmitted to the generator 12, and two pump shafts provided at
two hydraulic pumps constituting the dual pump 28 are driven by the
power of the electric motor 26 supplied with electric power from
the battery 14. The pressurized oil discharged from the two
hydraulic pumps is supplied to a working machine drive device 138
for driving a working machine, and a working machine raising and
lowering device 140 for raising and lowering the working machine
respectively to drive the working machine drive device 138 and the
working machine raising and lowering device 140. The working
machine raising and lowering device 140 may be, for example, a
working machine raising and lowering cylinder device. The working
machine drive device 138 may be, for example, the working machine
driving hydraulic motor 137 (see FIG. 14).
[0109] Further, as shown in FIG. 1c, the electric power from the
battery 14 is supplied to two wheel-driving electric motors 142 and
144 corresponding to two wheels to drive two wheel-driving electric
motors 142 and 144. Further, the controller 22, which is a control
unit, sends a control signal to a DC/DC converter not illustrated
connected to the battery 14, and controls the electric power taken
out from the battery 14. Further, the controller 22 sends a control
signal to inverters not illustrated connected respectively to the
electric motor 26 and the two wheel-driving electric motors 142 and
144 to control the respective output powers of the electric motor
26 and the two wheel-driving electric motors 142 and 144. The
controller 22 has electric power supply state selecting unit which
select whether to supply electric power to the electric motor 26
and the two wheel-driving electric motors 142 and 144 from the
battery 14, or to shut off the supply of the electric power to the
electric motor 26 and the two wheel-driving electric motors 142 and
144 from the battery 14. Except as described, the constitution
shown in FIG. 1c is otherwise the same as that of the first
embodiment described above with reference to FIG. 1a.
[0110] Next, FIG. 14 shows the constitution of a working vehicle
30b which is a vehicle with the multiple pump unit according to
this embodiment. The dual pump unit 16a is provided with neither
the PTO shaft 45 nor the PTO shaft side pulley 48 (see FIGS. 2 and
3) as in the second embodiment shown in FIG. 6 and described above.
Additionally, neither the PTO shaft 45a (FIGS. 6 and 8) which is
made selectively connectable by the clutch mechanism 110 nor the
engine side pulley 112 (FIGS. 6 and 8) is provided at the output
shaft of the engine 10. Instead, in the case of this embodiment,
the dual pump unit 16a and the working machine driving hydraulic
motor 137 corresponding to the working machine drive device 138
(FIG. 1c) are connected by a hydraulic pipe line 146, and the
working machine driving hydraulic motor 137 is made drivable by the
pressurized oil supplied from the dual pump unit 16a.
[0111] Further, the electric power from the battery 14 (see FIG.
1c) is supplied to a first electric motor 148 and a second electric
motor (not shown) which correspond to the wheel-driving electric
motors 142 and 144 (see FIG. 1c) and are for driving the wheels 32
to make the first electric motor 148 and the second electric motor
drivable. The mower 38 can be raised and lowered by the working
machine raising and lowering device 140 (see FIG. 1c).
[0112] As the constitution and operation are otherwise the same as
in the first embodiment shown in FIGS. 1a and 2 to 5 described
above, redundant explanation will be avoided by assigning the same
reference numerals and characters to the equivalent parts and not
repeating the description of these parts.
Eighth Embodiment of the Invention
[0113] FIG. 15a shows an eighth embodiment of the present
invention. In the case of this embodiment, a fuel cell system 152
having a fuel cell and a battery that is a secondary battery is
included instead of the engine 10 and the generator 12 (see FIG.
1a) in the first embodiment shown in FIGS. 1a and 2 to 5 and
described above. The fuel cell is constituted by stacking a
plurality of sets of fuel cells each including, for example, an
electrolyte film, an anode-side electrode and a cathode-side
electrode, and is supplied with oxidized gas such as air and fuel
gas such as hydrogen gas to generate electric power by
electrochemical reaction. The generated electric power is supplied
to the electric motor 26 directly or via the secondary battery.
Further, the electric power drawn from either the battery or the
fuel cell is controlled by the controller 22.
[0114] As the constitution and operation are otherwise the same as
those in the first embodiment shown in FIGS. 1a and 2 to 5
described above, redundant illustration and explanation will be
avoided by assigning the same reference numerals and characters to
the equivalent parts and not repeating their description here.
Ninth Embodiment of the Invention
[0115] FIG. 15b shows a ninth embodiment of the present invention.
In this embodiment, the fuel cell system 152 having a fuel cell and
a battery that is a secondary battery is included instead of the
engine 10 and the generator 12 (see FIG. 1a), in the seventh
embodiment shown in FIGS. 1c and 14 described above. The
constitution and operation of the fuel cell are the same as in the
eighth embodiment shown in FIG. 15a described above. The electric
power generated by the fuel cell is supplied to the electric motor
26 directly or via the battery.
[0116] The constitution and operation are otherwise the same as in
the first embodiment shown in FIGS. 1a and 2 to 5 or in the eighth
embodiment shown in FIG. 15a.
Tenth Embodiment of the Invention
[0117] FIG. 16 is a sectional view showing a drive device part of
the wheel 32 at one side of the two wheels 32 which are the rear
wheels in a working vehicle, being a vehicle with a multiple pump
unit of a tenth embodiment of the present invention. In the present
embodiment, in a device according to the first embodiment shown in
FIGS. 1a and 2 to 5 and described above, a rotary shaft 154
constituting the first hydraulic motor 34 is made drivable by the
pressurized oil being supplied to the first hydraulic motor 34. The
rotational force of the rotary shaft 154 is decelerated by the
planetary gear mechanism 78 and provided to drive the wheel 32.
Specifically, the planetary gear mechanism 78 includes a sun gear
156 provided at one end portion (right end portion in FIG. 16) of
the rotary shaft 154, a pinion gear 158 and a ring gear 160. A
pinion shaft 162 is supported in the pinion gear 158, and by the
pinion shaft 162, a wheel support member 164 fixed to the wheel 32
is rotated. The wheel support member 164 rotates with respect to
the frame 42 (see FIGS. 2, 3 and the like) or a housing 166 fixed
to a suspension system. A tip end portion of a bolt fixed by a
screw to the housing 166 from outside in the diameter direction is
engaged in a recessed portion 168 formed in an outer peripheral
surface of the ring gear 160 to support the ring gear 160 to be
incapable of rotating with respect to the housing 166. Thereby, the
rotation of the rotary shaft 154 is decelerated by the planetary
gear mechanism 78 and is transmitted to the wheel 32.
[0118] Further, a braking device 170 is provided at the other end
portion (left end portion in FIG. 16) side of the rotary shaft 154.
The braking device 170 includes a brake lever 172, and the brake
lever 172 swings by pushing and pulling a cable, not shown,
connected to the brake lever 172. Through a swinging motion, a
variable member 174 extends in a circumferential direction via a
cam mechanism and the like to press an annular member 176 fixed to
the rotary shaft 154 to brake the wheel 32. The constitution of a
drive device part for a wheel on the other side not shown in FIG.
16 is the same except that the left and the right are reversed from
the above described constitution.
[0119] As the constitution and operation are otherwise the same as
in the first embodiment shown in FIGS. 1a and 2 to 5 described
above, redundant illustration and explanation will be omitted.
[0120] The braking structure provided in the wheel support
structure is not limited to the structure as in this embodiment,
but, for example, a disc brake and an electromagnetic brake can be
adopted.
[0121] In this embodiment, instead of the first hydraulic motor 34
and the second hydraulic motor 36 (see FIGS. 3, 4 and the like),
the first electric motor 148 and the second electric motor
constituting the eighth embodiment shown in FIG. 14 described above
can be used. In such a case, a rotary shaft corresponding to the
rotary shaft 154 in FIG. 16 is driven by the first electric motor
148 and the second electric motor.
Eleventh Embodiment of the Invention
[0122] FIG. 17 is a sectional view similar to FIG. 16 described
above in a working vehicle, which is a vehicle with a multiple pump
unit of an eleventh embodiment of the present invention. In this
embodiment, planetary gear mechanisms 178a and 178b are adopted in
two stages. Specifically, the pinion shaft 162 constituting the
planetary gear mechanism 178a of the first stage is supported on a
carrier 180, and the carrier 180 is engaged with a second sun gear
184 provided on an outer peripheral surface of a second rotary
shaft 182 which is supported coaxially with the rotary shaft 154
and rotatable relatively to each other. A second pinion gear 186
constituting the planetary gear mechanism 178b of the second stage
is meshed with the second sun gear 184 and a second ring gear 190
so that the wheel support member 164 is rotated by a second pinion
shaft 188 supported at the second pinion gear 186.
[0123] Further, the ring gear 160 constituting the planetary gear
mechanism 178a of the first stage and the second ring gear 190
constituting the planetary gear mechanism 178b of the second stage
are fixed to the housing 166 inside the wheel support member 164.
For this purpose, a plurality of pins 192 are inserted through the
holes formed in part of the housing 166, and one end portions
(lower end portions in FIG. 17) of the pins 192 are locked to
recessed portions provided on the outer peripheral surfaces of the
ring gear 160 and the second ring gear 190. Inner rings of a pair
of bearings are opposed to the other end portion (upper end portion
in FIG. 17) of the pin 192 to prevent the pin 192 from removing
from the housing 166. Thereby, the ring gear 160 and the second
ring gear 190 are supported in a manner such that they are
incapable of rotating with respect to the housing 166. With a
configuration as described, the rotation of the rotary shaft 154 is
decelerated in two stages by the planetary gear mechanisms 178a and
178b of the two stages. The constitution of a drive device part for
a wheel on the other side not shown in FIG. 17 is the same as the
above described constitution except that the left and right are
reversed.
[0124] As the constitution and operation are otherwise the same as
those in the tenth embodiment shown in FIG. 16 described above,
redundant explanation will be avoided by assigning the same
reference numerals and characters to the equivalent parts and not
repeating their explanation.
Twelfth Embodiment of the Invention
[0125] FIG. 18 is a view corresponding to an enlarged section of a
part C in FIG. 16 in a working vehicle, which is a vehicle with a
multiple pump unit of a twelfth embodiment of the present
invention. In the this embodiment, in the tenth embodiment shown in
FIG. 16 described above, in order to dispose the ring gear 160 such
that it is incapable of rotating with respect to the housing 166,
the pin 192 is inserted through a through-hole 194 formed in the
housing 166, and one end portion of the pin 192 (lower end portion
in FIG. 18) is locked to a recessed portion formed in the outer
peripheral surface of the ring gear 160. Further, a C-shaped snap
ring 196 is locked to an annular recessed portion 198 leading to an
outside diameter side end portion of the through-hole 194. One
surface of the snap ring 196 is opposed to an inner ring of one
bearing, and thereby, positioning of the bearing is achieved.
[0126] The constitution and operation are otherwise the same as in
the tenth embodiment shown in FIG. 16 described above.
Thirteenth Embodiment of the Invention
[0127] FIG. 19 is view corresponding to an enlarged section of a
part D in FIG. 16 in a working vehicle, which is a vehicle with a
multiple pump unit of a thirteenth embodiment of the present
invention. In the this embodiment, in a configuration according to
the tenth embodiment shown in FIG. 16 and described above, in order
to dispose the ring gear 160 such that it is incapable of rotating
with respect to the housing 166, the pin 192 is inserted through
the through-hole 194 formed in the housing 166, and one end portion
(lower end portion in FIG. 18) of the pin 192 is locked to the
recessed portion formed in the outer peripheral surface of the ring
gear 160. In this embodiment, the bearing for supporting the wheel
support member 164 rotatably with respect to the housing 166 is a
needle bearing, rather than a pair of ball bearings as in the tenth
embodiment shown in FIG. 16, and prevention of the pin 192 from
removing from the housing 166 is achieved by an inner ring (collar)
constituting the needle bearing.
[0128] Further, a bearing 200 is provided between one end portion
(right end portion in FIG. 19) of the rotary shaft 154 and the
wheel support member 164. In order to prevent removal of the
bearing 200 with respect to the rotary shaft 154, a nut 202 is
connected by a screw to one end portion of the rotary shaft 154.
Prevention of removal of the bearing 200 with respect to the rotary
shaft 154 can also be achieved without the nut 202, by locking a
snap ring to a locking groove formed in the outer peripheral
surface of one end portion of the rotary shaft 154, and by opposing
the snap ring to the bearing 200.
[0129] The constitution and operation are otherwise the same as in
the tenth embodiment shown in FIG. 16 described above.
Fourteenth Embodiment of the Invention
[0130] FIG. 20 shows a hydraulic circuit of a dual pump unit 16f,
which is a multiple pump unit of the fourteenth embodiment of the
present invention, and a constitution of a working vehicle loaded
with the dual pump unit 16f. In this example, the working vehicle
is a tractor or the like having an attached cultivator, not
illustrated that is a working machine. Such a working vehicle of
this embodiment includes a pair of link mechanisms, not
illustrated, for adjusting the tilt angle of the cultivator with
respect to the ground, and a pair of extending and contracting
hydraulic cylinder devices 204a and 204b which are actuators for
extending and contracting arms constituting a pair of link
mechanisms. Further, the working vehicle includes a raising and
lowering hydraulic cylinder device 206 which is an actuator for
raising and lowering the cultivator. In such a working vehicle, as
in the case of the second embodiment shown in FIG. 8 described
above, the generator 12 is driven by the engine 10 to generate
electric power, and the generated electric power is supplied to the
battery 14. Further, the electric motor 26 is made drivable by the
electric power from the battery 14.
[0131] Further, the electric power from the battery 14 can be
supplied to the first electric motor 148 and the second electric
motor 150, which are wheel-driving electric motors for driving the
two wheels 32. The electric power drawn from the battery 14 is
controlled by the controller 22. The first electric motor 148 and
the second electric motor 150 drive the wheels 32 via the planetary
gear mechanisms 78. The electric motor 26 can drive a first pump
shaft of a first hydraulic pump 54a and the second pump shaft
constituting the second hydraulic pump 56, which constitute the
dual pump unit 16f. The basic constitution for driving the first
pump shaft and the second pump shaft is the same as that of the
dual pump unit 16a of the second embodiment shown in FIG. 9
described above.
[0132] Especially in the dual pump unit 16f of this embodiment, as
a discharge port of the first hydraulic pump 54a, two kidney-shaped
(reniform) or arc-shaped discharge holes are formed at an outer
side and an inner side with respect to the diameter direction in
the portion existing around the first pump shaft. Thus, the first
hydraulic pump 54a is formed as a double port pump provided with
two discharge ports corresponding to the one first pump shaft.
Through the driving of the first pump shaft, the pressurized oil is
simultaneously fed out from the two discharge ports of the first
hydraulic pump.
[0133] Oil is fed to the first hydraulic pump 54a and the second
hydraulic pump 56 from the external tank 72 via the filter 70 and
then pressurized, so that the pressurized oil is supplied to a pair
of the extending and contracting hydraulic cylinder devices 204a
and 204b and the raising and lowering hydraulic cylinder device
206. Specifically, the pressurized oil discharged from one
discharge port out of the two discharge ports of the first
hydraulic pump 54a is capable of being selectively supplied to two
chambers of an extending and contracting hydraulic cylinder 210a by
a switching valve 208a constituting the one extending and
contracting hydraulic cylinder device 204a of the pair of extending
and contracting hydraulic cylinder devices 204a and 204b. The
pressurized oil discharged from the other discharge port out of the
two discharge ports of the first hydraulic pump 54a is capable of
being selectively supplied to two chambers of a raising and
lowering hydraulic cylinder 214 by a switching valve 212
constituting the raising and lowering hydraulic cylinder device
206.
[0134] On the other hand, the pressurized oil discharged from the
discharge port of the second hydraulic pump 56 is capable of being
selectively supplied to two chambers of an extending and
contracting hydraulic cylinder 210b by a switching valve 208b
constituting the other extending and contracting hydraulic cylinder
device 204b of the pair of extending and contracting hydraulic
cylinder devices 204a and 204b. Further, in the neutral positions
of the switching valves 208a, 212 and 208b, the pressurized oil
from the first hydraulic pump 54a or the second hydraulic pump 56
is returned to the casing 44. The oil reservoir in the casing 44 is
caused to communicate with the tank 72.
[0135] According to such a working vehicle, as in each of the above
described embodiments, quieter performance can be achieved because
it is not necessary that the engine 10 be continually operated in
order to raise and lower the cultivator or displace the tilt of the
cultivator. Further, with the constitution in which the first
hydraulic pump 54a is made a double port pump provided with the two
discharge ports corresponding to the first pump shaft, and the
pressurized oil for operating the extending and contracting
hydraulic cylinder device 204a and the raising and lowering
hydraulic cylinder device 206 which are the two actuators is fed
out from the two discharge ports of the first hydraulic pump 54a,
the pressurized oil for actuating a larger number of actuators is
fed out from the first hydraulic pump 54a and the second hydraulic
pump 56, and can operate a larger number of actuators. Therefore,
operability can be further enhanced.
[0136] Although in this example the cultivator is driven by a
working machine driving electric motor (not illustrated) supplied
with electric power from the engine 10 or the battery 14, the
cultivator can be also driven by a hydraulic motor supplied with
the pressurized oil from the first hydraulic pump 54a or the second
hydraulic pump 56. Specifically, in FIG. 20, instead of any of the
pair of extending and contracting hydraulic cylinder devices 204a
and 204b, a working machine drive device which is an actuator, that
is, a working machine driving hydraulic motor, can be provided. The
constitution of the dual pump unit 16f shown in FIG. 20 is
otherwise the same as that of the second embodiment shown in FIGS.
8 to 9 and described above. Instead of the engine 10, the fuel cell
system 152 can be used as in the eighth embodiment and the ninth
embodiment shown in FIGS. 15a and 15b described above.
[0137] The dual pump unit 16f of this embodiment shown in FIG. 20
is installed on the working vehicle 30b of the seventh embodiment
shown in FIG. 14 described above, and the working machine driving
hydraulic motor 137 and the wheel-driving hydraulic motors
corresponding to the two wheels can be driven by the dual pump unit
16f. In this case, the pressurized oil from the two discharge ports
of the first hydraulic pump 54a (FIG. 20), for example, is supplied
to the one wheel-driving hydraulic motor and the working machine
driving hydraulic motor 137, and the pressurized oil from the
discharge port of the second hydraulic pump 56 (FIG. 20) is
supplied to the other wheel-driving hydraulic motor.
Fifteenth Embodiment of the Invention
[0138] FIG. 21 is a diagram showing a basic constitution and a
hydraulic circuit of a working vehicle which is a vehicle with a
multiple pump unit of a fifteenth embodiment of the present
invention. In this embodiment, as in the first embodiment shown in
FIG. 4 and described above, the first hydraulic pump 54 and the
second hydraulic pump 56 constituting the dual pump 28 are driven
by the electric motor 26. The electric motor 26 is driven by the
electric power supplied from the battery 14.
[0139] The pressurized oil discharged from the first hydraulic pump
54 is supplied to a first hydraulic motor 34a corresponding to the
wheel 32 on one side of the wheels 32 on the left and right (upper
side in FIG. 21), and drives the wheel 32 on the one side via the
planetary gear mechanism 78. The pressurized oil discharged from
the second hydraulic pump 56 is supplied to a second hydraulic
motor 36a corresponding to the wheel 32 on the other side (lower
side in FIG. 21) of the wheels on the left and right, and drives
the wheel 32 on the other side via the planetary gear mechanism
78.
[0140] Especially in this embodiment, the first hydraulic motor 34a
and the second hydraulic motor 36a are both variable displacement
hydraulic motors. For example, each of the hydraulic motors 34a and
36a may be a swash plate type variable displacement piston motor.
For example, a plurality of piston cylinder mechanisms disposed
around the motor rotary shaft of each of the hydraulic motors 34a
and 36a, and a movable swash plate mechanism which restricts a
stroke length of each piston when a plurality of piston cylinder
mechanisms rotate around the motor rotary shaft are included. The
movable swash plate mechanism controls the degree of inclination
with respect to the motor rotary shaft by a swash plate control
shaft. Specifically, a tilt angle of the swash plate is made
adjustable. The tilt angle of the swash plate of each of the
hydraulic motors 34a and 36a changes in two stages of predetermined
large displacement and small displacement or continuously within a
range from a predetermined large displacement to a predetermined
small displacement, in correspondence with a control signal from
the controller 22 (see FIG. 1a), based on an operation of a driver,
for example.
[0141] In the case of a working vehicle using such variable
displacement hydraulic motors 34a and 36a, the wide range of the
deceleration ratio makes it possible to more easily respond to
increases in speed of the working vehicle than possible with the
working vehicle using a fixed displacement hydraulic motor.
[0142] As the constitution and operation are otherwise the same as
those in the first embodiment shown in FIGS. 1a and 2 to 5
described above, redundant illustration and explanation will be
omitted.
FIRST REFERENCE EXAMPLE RELATING TO THE PRESENT INVENTION
[0143] FIG. 22 is a diagram showing a basic constitution and a
hydraulic circuit of a working vehicle, which is a vehicle with a
multiple pump unit of a first reference example relating to the
present invention. This reference example is out of "What is
claimed is:" of the present invention. In the case of this
reference example, in the same constitution as the first embodiment
shown in FIGS. 1a and 2 to 5 described above, the cooling fan 96 is
fixed to the end portion of the drive shaft 114 constituting the
electric motor 26 as in the case of the dual pump unit 16b of the
third embodiment shown in FIG. 10 described above. The drive shaft
114 constitutes the first pump shaft constituting the first
hydraulic pump 54. The charge pump 68 is made drivable by the end
portion of the drive shaft 114. The electric motor 26 is driven by
the electric power from the battery 14 which is supplied with the
electric power from the generator 12 driven by the engine 10 as in
the first embodiment shown in FIG. 4 described above.
[0144] In contrast to each of the above-described embodiments of
the present invention, in this reference example, no second
hydraulic pump 56 (see FIG. 4 and the like) is provided. Therefore,
no gear mechanism for driving the pump shaft constituting the
second hydraulic pump 56 by the drive shaft 114 is provided.
Specifically, the electric motor 26 drives only the first hydraulic
pump 54 of the hydraulic pumps. The charge pump 68 has the function
of replenishing oil lost due to leakage, such as through gaps in
the respective parts when oil circulates in the hydraulic circuit
and the like. More specifically, the charge pump 68 sucks oil from
the external tank 72 via the filter 70, pressurizes the oil, and
supplies the oil to the hydraulic path at the low pressure side via
the check valve 74. Specifically, the discharge side of the charge
pump 68 is connected to the charge line 220, and the relief valve
76 has the function of keeping the hydraulic pressure of the charge
line 220 at a predetermined value. The first hydraulic pump 54 is
housed in a casing 44a. The external tank 72 draws oil from the
inside of the casing 44a and supplies the oil to the charge pump 68
via the filter 70.
[0145] The pressurized oil discharged from the first hydraulic pump
54 is supplied to an axle rotating hydraulic motor 224. A pinion
shaft 228 constituting an input part of a differential gear device
226 is rotationally driven by a rotary shaft (not shown)
constituting the axle rotating hydraulic motor 224. Further, side
gears (not shown) at both left and right sides constituting the
differential gear device 226 are rotated by the rotation of the
pinion shaft 228. The side gears are fixed to an axle 230 connected
to the left and right wheels 32. Therefore, by the rotational drive
of the axle rotating hydraulic motor 224, the left and right wheels
32 are rotated. By reversing the tilting direction of the swash
plate of the first hydraulic pump 54, that is, the direction in
which the swash plate inclines with rotation, the hydraulic motor
224 is made rotatable in any normal or reverse direction.
[0146] Further, the axle rotating hydraulic motor 224 is provided
with a bypass valve 84 in a bypass route disposed in parallel with
respect to the flow of the pressurized oil, so that, when the
bypass valve 84 is opened, shortcut is taken between the discharge
side and the suction side of the axle rotating hydraulic motor 224.
Thereby, when it is desired that the working vehicle 30 be forcibly
moved, for example, in a state in which the electric motor is
stopped and the like, the load on the axle rotating hydraulic motor
224 can be removed.
[0147] Free wheel preventing lines 234 for drawing pressurized oil
from the reservoir inside the casing 44a are respectively connected
at a discharge side and a suction side at the time of normal
rotation of the first hydraulic pump 54 of a main pressurized oil
line 232 connecting the first hydraulic pump 54 and the axle
rotating hydraulic motor 224. Second check valves 236 are provided
at the respective free wheel preventing lines 234. The second check
valve 236 has the function of replenishing pressurized oil to the
main pressurized oil line 232 from the reservoir to prevent the
working vehicle from slipping down due to shortage of the
pressurized oil of part of the main pressurized oil line 232 when
the working vehicle stops on an uphill or a downhill.
[0148] The main pressurized oil line 232, the charge line 220, the
axle rotating hydraulic motor 224, the bypass valve 84, the
differential gear device 226 and a portion including part of the
axle 230 are housed in the casing 44a housing the electric motor 26
and the first hydraulic pump 54, and the casing 44a and the
elements housed in the casing 44a are set as a single unit.
[0149] In the reference example as above, as in each of the
above-described embodiments, when electric power is supplied to the
battery 14 (see FIG. 4) from the generator 12 (see FIG. 4) driven
by the engine 10 (see FIG. 4) and the electric power is supplied to
the electric motor 26 from the battery 14, the axle rotating
hydraulic motor 224 for driving the wheels 32 can be operated
without always operating the engine 10, unlike in the structure
which drives the drive shaft 114 by the power of the engine 10
without the electric motor 26. Therefore, a structure capable of
quieter operation is obtained. Specifically, when sufficient
electric power is stored in the battery 14, the axle rotating
hydraulic motor 224 corresponding to the wheels 32 can be driven by
driving the electric motor 26 by the electric power from the
battery 14 in the sate in which the engine 10 is stopped and
driving noise is small.
[0150] As the constitution and operation are otherwise the same as
those in the above-described first embodiment, redundant
explanation will be omitted by assigning the same reference
numerals and characters to the equivalent parts and not repeating
their explanation here.
SECOND REFERENCE EXAMPLE RELATING TO THE PRESENT INVENTION
[0151] FIG. 23 is a diagram showing a basic constitution and a
hydraulic circuit of a working vehicle, which is a vehicle with a
multiple pump unit of a second reference example relating to the
present invention. This reference example is also out of "What is
claimed is:" of the present invention. This reference example
differs form the first reference example shown in FIG. 22 described
above in that a second casing 240 which houses the axle rotating
hydraulic motor 224, the differential gear device 226, and a
portion including part of the axle 230, is provided apart from a
first casing 238 which houses the electric motor 26, the first
hydraulic pump 54, and the bypass valve 84. The first casing 238
and the second casing 240 are provided at different locations as
separate components. Specifically, a hydraulic circuit part
including the first hydraulic pump 54 and a hydraulic circuit part
including the axle rotating hydraulic motor 224 are set as separate
units different from each other. A hydraulic pipe line 242 is
connected to the first casing 238 and the second casing 240. The
hydraulic pipe line 242 constitutes part of the main pressurized
oil line 232. Oil reservoirs of the first casing 238 and the second
casing 240 are connected to the external tank 72.
[0152] Further, the charge pump 68 is disposed between the first
hydraulic pump 54 and the electric motor 26, so that the first
hydraulic pump 54, the electric motor 26 and the charge pump 68 may
be rotationally driven at the same time by the drive shaft 114.
Unlike this reference example, the first hydraulic pump 54, the
electric motor 26 and the charge pump 68 are disposed to be in the
same positional relationship as in the first reference example
shown in FIG. 22 described above so that the charge pump 68 may be
made drivable by the end portion of the drive shaft 114.
[0153] In the case of this reference example as above, in the
working vehicle, the degree of freedom of disposition of the parts
can be enhanced to a greater degree than in the first reference
example shown in FIG. 22 described above. For example, the degree
of freedom of disposition of the first hydraulic pump 54 is
enhanced.
[0154] As the constitution and operation are otherwise the same as
in the first reference example shown in FIG. 22 described above,
redundant explanation will be avoided by assigning the same
reference numerals and characters to the equivalent parts and not
repeating their description here.
Sixteenth Embodiment of the Present Invention
[0155] FIG. 24 is a diagram showing a basic constitution and a
hydraulic circuit of a working vehicle, which is a vehicle with a
multiple pump unit of a sixteenth embodiment of the present
invention. In this embodiment, in the constitution of the first
embodiment shown in FIG. 4 described above, a gear mechanism for
transmitting power to the second pump shaft 60 from the drive shaft
114 is not provided between the drive shaft 114 constituting the
first pump shaft of the first hydraulic pump 54 and the second pump
shaft 60 of the second hydraulic pump 56.
[0156] In this embodiment, the electric motor 26, the first
hydraulic pump 54, the first hydraulic motor 34 and the planetary
gear mechanism 78 corresponding to the first hydraulic motor 34 are
housed in a first casing 244, and the second hydraulic pump 56, the
second hydraulic motor 36 and the planetary gear mechanism 78
corresponding to the second hydraulic motor 36 are housed in a
second casing 246. Further, a charge pump 68a is driven by the
second pump shaft 60. The charge pump 68a is housed in the second
casing 246, pressurizes the oil sucked from the oil reservoir in
the second casing 246, and supplies the oil to a hydraulic path at
a low pressure side via the check valve 82.
[0157] The cooling fan 96 and a drive side pulley 248 are fixed to
the drive shaft 114 projected outside the first casing 244. The
cooling fan 96 and a driven side pulley 250 are fixed to the second
pump shaft 60 projected outside the second casing 246. A belt 252
is looped over the drive side pulley 248 and the driven side pulley
250. Therefore, when the drive shaft 114 rotates, the second pump
shaft 60 also rotates via the belt 252. Specifically, the drive
shaft 114 and the second pump shaft 60 are operationally
connected.
[0158] Suction sides of the charge pump 68 which is driven by the
drive shaft 114 and the charge pump 68a which is driven by the
second pump shaft 60 are respectively connected to the oil
reservoirs inside the first casing 244 and the second casing 246.
Further, a manual switching valve 254 is provided in a bypass path
disposed in parallel with respect to the flow of the pressurized
oil for each of the hydraulic pumps 54 and 56. By switching the
manual switching valve 254, it is possible to select whether to
continue the bypass path at a region of the manual switching valve
254, or to cause the suction side and the discharge side of the
hydraulic pump 54 (or 56) to communicate with the oil reservoir
inside the first casing 244 or the second casing 246. In the
present example, as in the first embodiment shown in FIGS. 1a and 2
to 5 and described above, the drive shaft 114 and the second pump
shaft 60 driven by the electric motor 26, and the first hydraulic
pump 54 and the second hydraulic pump 56 which are driven by the
respective shafts 114 and 60 are included, and the pressurized oil
for operating the first hydraulic motor 34 and the second hydraulic
motor 36 corresponding to the left and right wheels 32 is fed out
from the respective hydraulic pumps 54 and 56. In this embodiment,
the casings 244 and 246 are set as separate units from each other,
but by connecting them with a member not illustrated, they can
constitute a single unit.
[0159] As the constitution and operation are otherwise the same as
in the first embodiment described above, redundant explanation will
be avoided by assigning the same reference numerals and characters
to the equivalent parts and not repeating their description
here.
THIRD REFERENCE EXAMPLE RELATING TO THE PRESENT INVENTION
[0160] FIG. 25 is a diagram showing a basic constitution and a
hydraulic circuit of a working vehicle which is a vehicle with a
multiple pump unit of a third reference example relating to the
present invention. This reference example is out of "What is
claimed is:" of the present invention. The configuration of this
reference example corresponds to that of the sixteenth embodiment
shown in FIG. 24 described above, with the exception that the drive
shaft 114 constituting the first pump shaft of the first hydraulic
pump 54 and the second pump shaft of the second hydraulic pump 56
are not operationally connected. In the present example, the second
pump shaft is constituted of a second drive shaft 256, and the
second drive shaft 256 constitutes a rotary shaft of a second
electric motor 258 as in the case of the drive shaft 114
constituting the first pump shaft. Specifically, the first
hydraulic pump 54 and the second hydraulic pump 56 are driven by
the electric motor 26 and second electric motor 258, respectively,
which are separate components. Further, the cooling fan 96 is fixed
to a portion of the second drive shaft 256 constituting the second
electric motor 258 projecting outside the second casing 246. The
second electric motor 258 is controlled by the controller 22 (see
FIG. 1a) similarly to the electric motor 26 for driving the first
hydraulic pump 54, is supplied with electric power from the battery
14 (see FIG. 4), and is driven at a rotational speed equal to the
electric motor 26. With such a constitution, the first hydraulic
pump 54 and the second hydraulic pump 56 are driven independently
from each other, but their rotation at the input sides are the same
as each other, and, if the tilting amount of each swash plate, that
is, the inclined amount at the time of rotation is the same, the
working vehicle travels in a straight line, whereas, if the tilting
amount is changed, the traveling direction can be changed.
[0161] As the constitution and operation are otherwise the same as
in the sixteenth embodiment shown in FIG. 24 described above, the
redundant explanation will be avoided by assigning the same
reference numerals and characters to the equivalent parts.
[0162] Further, in each of the above described embodiments,
electric power can be directly supplied to the electric motor 26
from the generator 12 or the fuel cell instead of supplying the
electric power generated in the generator 12 or the fuel cell to
the secondary battery such as the battery 14 and supplying the
electric power to the electric motor 26 from the secondary battery.
In such a case, power supply switching unit may be provided at
either the generator 12 or the fuel cell, or between the secondary
battery and the electric motor 26, and by the power supply
switching unit, supply of the electric power to the electric motor
26 directly from the generator 12 or the fuel cell, or supply of
the electric power to the electric motor 26 from the secondary
battery can be made switchable automatically or manually by an
operation part such as a switch. For example, when the charge
amount of the secondary battery is at a predetermined value or
less, electric power can be automatically supplied to the electric
motor 26 directly from the generator 12 or the fuel cell.
[0163] Of the above-described respective embodiments, in the case
of driving the working machine except for the wheels 32 which are
the drive wheels by hydraulic pressure from the hydraulic pump in
the fourteenth embodiment shown in FIG. 20 and the like, at least
one hydraulic pump which drives the working machine out of a
plurality of hydraulic pumps constituting the dual pump unit can be
made a fixed displacement type instead of a variable displacement
type. Although in the above-described embodiments, examples of
providing the two hydraulic pumps constituting the dual pump unit
are described, three or more hydraulic pumps may be provided, and
each of the three or more hydraulic pumps can be driven by one
electric motor. Further, in the above-described respective
embodiments and reference examples, the wheels 32 driven by the
hydraulic motor or the electric motor are not limited to the rear
wheels as shown in the illustrated examples, but may also be the
front wheels. Further, in the case of the constitution having the
electric device which drives the wheels via the hydraulic
transmission as in each of the above described embodiments, the
electric motor rotates at a constant speed, as compared with the
case of directly driving the wheels with the electric motor.
Therefore, the additional advantage is obtained that the control
device of the electric motor and the electric motor itself can be
manufactured at a relatively low cost.
* * * * *