U.S. patent application number 13/196204 was filed with the patent office on 2012-08-09 for apparatus for controlling the angle of a swash plate of a hydraulic pump.
Invention is credited to Chul Hwan CHOI.
Application Number | 20120198994 13/196204 |
Document ID | / |
Family ID | 46599760 |
Filed Date | 2012-08-09 |
United States Patent
Application |
20120198994 |
Kind Code |
A1 |
CHOI; Chul Hwan |
August 9, 2012 |
APPARATUS FOR CONTROLLING THE ANGLE OF A SWASH PLATE OF A HYDRAULIC
PUMP
Abstract
The present disclosure relates to an apparatus for controlling
the angle of a swash plate of a hydraulic pump, and more
particularly, to an apparatus for controlling the angle of a swash
plate of a hydraulic pump in order to fix the swash plate at a
desired angle by using an electric motor and an electromagnet. The
apparatus for controlling the angle of a swash plate of a hydraulic
pump includes a swash plate and a swash plate shaft coupled to the
swash plate to be rotatable, and the apparatus further includes: an
electric motor which directly connects the swash plate shaft or
transmits a rotating force through a link connected to the swash
plate shaft to pivot the swash plate; and an electromagnet which
generates a magnetic force so that the swash plate moving according
to the operation of the electric motor is fixed at a target
angle.
Inventors: |
CHOI; Chul Hwan; (Anyang-si,
KR) |
Family ID: |
46599760 |
Appl. No.: |
13/196204 |
Filed: |
August 2, 2011 |
Current U.S.
Class: |
91/506 |
Current CPC
Class: |
F04B 1/324 20130101 |
Class at
Publication: |
91/506 |
International
Class: |
F04B 1/32 20060101
F04B001/32 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 7, 2011 |
KR |
10-2011-0010608 |
Claims
1. An apparatus for controlling the angle of a swash plate of a
hydraulic pump, which includes a swash plate and a swash plate
shaft coupled to the swash plate to be rotatable, the apparatus
comprising: an electric motor which directly connects the swash
plate shaft or transmits a rotating force through a link connected
to the swash plate shaft to pivot the swash plate; and an
electromagnet which generates a magnetic force so that the swash
plate moving according to the operation of the electric motor is
fixed at a target angle.
2. The apparatus for controlling the angle of a swash plate of a
hydraulic pump according to claim 1, wherein the electromagnet is
mounted in the electric motor to apply a magnetic force to a rotary
shaft of the electric motor so that the electric motor stops
rotation.
3. The apparatus for controlling the angle of a swash plate of a
hydraulic pump according to claim 1, wherein the electromagnet is
disposed adjacent to the link which connects the swash plate shaft
to the electric motor and applies a magnetic force to the link so
that the link is fixed.
4. The apparatus for controlling the angle of a swash plate of a
hydraulic pump according to claim 1, wherein the electromagnet is
switched off while the electric motor is operating, and the
electromagnet is switched on if the swash plate reaches a target
angle so that the swash plate is fixed due to the magnetic force.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to Korean Patent
Application No. 10-2011-0010608, filed on Feb. 7, 2011, and all the
benefits accruing therefrom under 35 U.S.C. .sctn.119, the contents
of which in its entirety are herein incorporated by reference.
BACKGROUND
[0002] 1. Field
[0003] The present disclosure relates to an apparatus for
controlling the angle of a swash plate of a hydraulic pump, and
more particularly, to an apparatus for controlling the angle of a
swash plate of a hydraulic pump in order to fix the swash plate at
a desired angle by using an electric motor and an
electromagnet.
[0004] 2. Description of the Related Art
[0005] A tractor or working vehicle may do plowing or flattening or
other agricultural works using the power of an engine, and a loader
or mower may be attached to the tractor to perform various kinds of
works. The tractor or working vehicle may be operated at various
speeds by means of an engine and a transmission, and the
transmission may employ a manual transmission, an automatic
transmission or a continuously variable transmission, similar to a
vehicle.
[0006] FIGS. 1 to 3 are schematic diagrams for illustrating how to
control the angle of a swash plate of a general hydro static
transmission (HST), and FIG. 4 is a graph showing an actual change
of the angle of a swash when the angle of a swash is controlled
using the configuration of FIG. 3.
[0007] Referring to FIGS. 1 to 3, the HST includes an axial
piston-type hydraulic pump 12 and a hydraulic motor 13. If an
engine 11 operates the hydraulic pump 12, a hydraulic pressure is
transmitted to the hydraulic motor 13 through a channel connected
to the hydraulic pump 12. Subsequently, the hydraulic motor 13
generates a rotating force by using the hydraulic pressure
transmitted from the hydraulic pump 12 to rotate a wheel 18 via a
reduction gear 17.
[0008] If the angle of the pivotable swash plate 14 is changed, an
amount of operating oil of the hydraulic pump 12 may increase or
decrease to change a flow rate. Accordingly, a rotating direction
and rotating speed of the output shaft of the hydraulic motor 13
may be adjusted.
[0009] In FIG. 1, a swash plate 14 of the hydraulic pump 12 is
directly connected to a driver pedal 15, and the driver may drive a
vehicle to a desired rotating direction or rotating speed by
manipulating the pedal 15. This configuration may be realized with
a low cost. However, if a load is applied to the wheel 18, the
pressure of the hydraulic pump 12 and the hydraulic motor 13
increases, and a great torque is applied to the swash plate 14.
Therefore, a driver should use a great force to manipulate the
pedal 15, which results in inconvenient manipulation.
[0010] In FIG. 2, a hydraulic valve 25 connected to a swash plate
24 of the hydraulic pump 12 is added to control the operation of
the swash plate 24 by a hydraulic pressure, and the angle of the
swash 24 may be manipulated with a consistent force regardless of
the load from the wheel 18 of the vehicle. In addition, an
electronic hydraulic valve 25 may be installed to perform automatic
transmission suitable for conditions, but this configuration is
expensive.
[0011] In FIG. 3, an electric motor 35 connected to a swash plate
34 of the hydraulic pump 12 is added to control the operation of
the swash plate 34 by a rotating force of the electric motor 35.
This configuration is cheap and may perform transmission regardless
of the load. However, this configuration has a problem in that the
electric motor 35 may not be easily controlled.
[0012] In other words, as shown in FIG. 4, under the condition that
a load is generated at the wheel 18, as the pressure of the
hydraulic pump 12 and the hydraulic motor 13 increases, the swash
plate 34 generates a force to return to a neutral location.
Therefore, the electric motor 35 applies a rotating force to the
swash plate 34 by feed-back control so that the swash plate 34
departing from the control region moves to a target location.
However, in this process, the angle of the swash plate 34
fluctuates within the control region, which causes the operating
vehicle to fluctuate, makes the driver feel unpleasant and
deteriorates the durability of the electric motor 35.
[0013] In order to solve this problem, it is possible to increase
the capacity of the electric motor 35 or add a worm gear or a screw
to the electric motor 35 so that the power is not released.
However, these solutions have problems in that the size of the
motor increases or the cost increases.
SUMMARY
[0014] The present disclosure is directed to providing an apparatus
for controlling the angle of a swash plate of a hydraulic pump
which may fix the swash plate at a desired angle by using an
electric motor and an electromagnet.
[0015] In one aspect, there is provided an apparatus for
controlling the angle of a swash plate of a hydraulic pump, which
includes a swash plate and a swash plate shaft coupled to the swash
plate to be rotatable, the apparatus including: an electric motor
which directly connects the swash plate shaft or transmits a
rotating force through a link connected to the swash plate shaft to
pivot the swash plate; and an electromagnet which generates a
magnetic force so that the swash plate moving according to the
operation of the electric motor is fixed at a target angle.
[0016] The electromagnet may be mounted in the electric motor to
apply a magnetic force to a rotary shaft of the electric motor so
that the electric motor stops rotation.
[0017] The electromagnet may be disposed adjacent to the link which
connects the swash plate shaft to the electric motor and may apply
a magnetic force to the link so that the link is fixed.
[0018] The electromagnet may be switched off while the electric
motor is operating, and the electromagnet may be switched on if the
swash plate reaches a target angle so that the swash plate is fixed
due to the magnetic force.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The above and other aspects, features and advantages of the
disclosed exemplary embodiments will be more apparent from the
following detailed description taken in conjunction with the
accompanying drawings in which:
[0020] FIGS. 1 to 3 are schematic diagrams for illustrating the
angle control of a swash plate of a general hydro static
transmission (HST);
[0021] FIG. 4 is a graph showing an actual change of the angle of a
swash plate when the angle of the swash is controlled using the
configuration of FIG. 3;
[0022] FIGS. 5 and 6 are schematic views showing an apparatus for
controlling the angle of a swash plate of a hydraulic pump
according to an exemplary embodiment of the present disclosure;
and
[0023] FIGS. 7 and 8 are schematic view showing an apparatus for
controlling the angle of a swash plate of a hydraulic pump
according to another exemplary embodiment of the present
disclosure.
DETAILED DESCRIPTION
[0024] Exemplary embodiments now will be described more fully
hereinafter with reference to the accompanying drawings, in which
exemplary embodiments are shown. The present disclosure may,
however, be embodied in many different forms and should not be
construed as limited to the exemplary embodiments set forth
therein. Rather, these exemplary embodiments are provided so that
the present disclosure will be thorough and complete, and will
fully convey the scope of the present disclosure to those skilled
in the art. In the description, details of well-known features and
techniques may be omitted to avoid unnecessarily obscuring the
presented embodiments.
[0025] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the present disclosure. As used herein, the singular forms "a",
"an" and "the" are intended to include the plural forms as well,
unless the context clearly indicates otherwise. Furthermore, the
use of the terms a, an, etc. does not denote a limitation of
quantity, but rather denotes the presence of at least one of the
referenced item. The use of the terms "first", "second", and the
like does not imply any particular order, but they are included to
identify individual elements. Moreover, the use of the terms first,
second, etc. does not denote any order or importance, but rather
the terms first, second, etc. are used to distinguish one element
from another. It will be further understood that the terms
"comprises" and/or "comprising", or "includes" and/or "including"
when used in this specification, specify the presence of stated
features, regions, integers, steps, operations, elements, and/or
components, but do not preclude the presence or addition of one or
more other features, regions, integers, steps, operations,
elements, components, and/or groups thereof.
[0026] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art. It will be further
understood that terms, such as those defined in commonly used
dictionaries, should be interpreted as having a meaning that is
consistent with their meaning in the context of the relevant art
and the present disclosure, and will not be interpreted in an
idealized or overly formal sense unless expressly so defined
herein.
[0027] In the drawings, like reference numerals denote like
elements. The shape, size and regions, and the like, of the drawing
may be exaggerated for clarity.
[0028] Hereinafter, an apparatus for controlling the angle of a
swash plate of a hydraulic pump according to exemplary embodiments
of the present disclosure will be described in detail.
[0029] FIGS. 5 and 6 are schematic views showing an apparatus for
controlling the angle of a swash plate of a hydraulic pump
according to an exemplary embodiment of the present disclosure.
[0030] Referring to FIGS. 5 and 6, an apparatus for controlling the
angle of a swash plate according to the exemplary embodiment
includes an electric motor 150 and an electromagnet 160. The power
transmitted from an engine 11 progresses via hydro static
transmission (HST) 120 and a transmission 16 to a reduction gear
17. The engine 11, the HST 120 and the reduction gear 17 are
identical or similar to existing ones and therefore not described
in detail here.
[0031] The electric motor 150 is directly connected to a swash
plate shaft 142 of a hydraulic pump 12 or transmits a rotating
force through links 122 and 124 connected to the swash plate shaft
142 to pivot a swash plate 140. Though the electric motor 150 is
connected to the swash plate shaft 142 by the links 122 and 124 in
FIG. 6, the electric motor 150 may be directly connected to the
swash plate shaft 142. The swash plate shaft 142 is coupled to the
swash plate 140 to rotate integrally with the swash plate 140.
[0032] The electromagnet 160 generates a magnetic force so that the
swash plate 140 which moves according to the operation of the
electric motor 150 is fixed at a target location. In the exemplary
embodiment, the electromagnet 160 is mounted in the electric motor
150 to apply a magnetic force to the rotary shaft of the electric
motor 150 so that the electric motor 150 stops rotation.
[0033] The electromagnet 160 is magnetized to generate a magnetic
force if electric current flows thereon. If the electromagnet 160
is operated while the electric motor 150 operates, the magnetic
force may cause malfunction of the electric motor 150. Therefore,
the electromagnet 160 is switched off not to operate while the
electric motor 150 is operating, and if the swash plate 140 reaches
a target angle by the operation of the electric motor 150, the
electromagnet 160 is switched on to fix the rotary shaft of the
electric motor 150 by a magnetic force.
[0034] In other words, once the swash plate 140 reaches a target
angle, the operation of the electric motor 150 is stopped, and the
electromagnet 160 is operated so that the swash plate 140 maintains
a consistent angle. Accordingly, when a load is applied, it is not
needed to periodically operate the electric motor 150 so as to
maintain the angle of the swash plate 140, and the fluctuation of
the vehicle does not occur by the feed-back control of the electric
motor 150.
[0035] FIGS. 7 and 8 are schematic view showing an apparatus for
controlling the angle of a swash plate of a hydraulic pump
according to another exemplary embodiment of the present
disclosure.
[0036] Referring to FIGS. 7 and 8, the apparatus for controlling
the angle of a swash plate according to the exemplary embodiment
includes an electric motor 250 and an electromagnet 260 disposed
adjacent to links 222 and 224.
[0037] The electric motor 250 transmits a rotating force through
the links 222 and 224 connected to a swash plate shaft 242 to pivot
a swash plate 240. Since a control device of this embodiment is
configured using the electric motor 250, it is possible to perform
transmission of a vehicle at a low cost regardless of the load
applied to a wheel 18.
[0038] The electromagnet 260 is disposed adjacent to the links 222
and 224 which connects the swash plate shaft 242 to the electric
motor 250 and applies a magnetic force to the links 222 and 224 to
fix the links 222 and 224. As the links 222 and 224 are fixed by
the magnetic force of the electromagnet 260, the rotary shaft of
the electric motor 250 stops rotation.
[0039] As described above, the electromagnet 260 is switched off
not to operate while the electric motor 250 is operating, and if
the swash plate 240 reaches a target angle by the operation of the
electric motor 250, the electromagnet 260 is switched on to operate
to flow electric current and thus generate a magnetic force so that
the rotary shaft of the electric motor 250 is fixed.
[0040] The size and capacity of the electromagnet 160 and 260 may
be changed in various ways in consideration of a desired intensity
of a magnetic force according to the material of the links and the
rotary shaft of the electric motor 150 and 250.
[0041] The apparatus for controlling the angle of a swash plate of
a hydraulic pump according to the present disclosure allows the
swash plate to be fixed at a desired angle by using an electric
motor and an electromagnet.
[0042] In addition, the apparatus for controlling the angle of a
swash plate of a hydraulic pump according to the present disclosure
can reduce the frequent operations of the electric motor by adding
an electromagnet, which can improve the durability of the electric
motor.
[0043] Further, the apparatus for controlling the angle of a swash
plate of a hydraulic pump according to the present disclosure has a
simple design and can be added to and used for an existing
transmission at a low cost.
[0044] While the exemplary embodiments have been shown and
described, it will be understood by those skilled in the art that
various changes in form and details may be made thereto without
departing from the spirit and scope of the present disclosure as
defined by the appended claims.
[0045] In addition, many modifications can be made to adapt a
particular situation or material to the teachings of the present
disclosure without departing from the essential scope thereof.
Therefore, it is intended that the present disclosure not be
limited to the particular exemplary embodiments disclosed as the
best mode contemplated for carrying out the present disclosure, but
that the present disclosure will include all embodiments falling
within the scope of the appended claims.
* * * * *