Brakes – Wheel – Axially movable brake element or housing therefor
Reexamination Certificate
2001-01-04
2002-06-18
Schwartz, Christopher P. (Department: 3613)
Brakes
Wheel
Axially movable brake element or housing therefor
C188S071600, C188S170000, C188S26400E
Reexamination Certificate
active
06405835
ABSTRACT:
TECHNICAL FIELD
This invention relates to a brake device equipped hydraulic motor which is suitable for use, for example, as a hydraulic motor of a rotary drive mechanism or vehicular drive mechanism of a excavator or the like.
BACKGROUND ART
Illustrated by way of example in
FIGS. 8 through 13
is a prior art brake device equipped hydraulic motor which is applied as a hydraulic motor of a excavator rotary mechanism.
In these figures, indicated at
1
is a vehicular lower body, at
2
an upper rotary body which is rotatably mounted on the vehicular lower body
1
. Provided on the upper rotary body
2
is a frame
3
to support thereon a cab
4
, a housing cover
5
which internally defines a machine room and a counterweight
6
. Further, provided on a front portion of the upper rotary body
2
is a front working mechanism
7
with a member to be lifted up and down, for example, to perform an excavating operation. Being rotationally driven from a hydraulic motor
10
as described below, the upper rotary body
2
is rotated relative to the vehicular lower body
1
.
The hydraulic motor
10
of a rotary body drive mechanism (hereinafter referred to simply as “hydraulic motor”) is mounted on the rotary frame
3
of the upper rotary body
2
through a reducer (not shown), and, as described below, largely constituted by a casing
11
, output shaft
14
, cylinder block
15
and a brake device
22
.
As shown in
FIG. 9
, the casing
11
of the hydraulic motor
10
is constituted by a main casing body
12
of a stepped tubular shape provided with a cylindrical portion
12
A and bottom portion
12
B which is closed at a bottom end thereof, and a head casing
13
which is adapted to close the other open end of the main casing body
12
. Further, the main casing body
12
is provided with an annular flange
12
C around an outer periphery of its bottom portion
12
B. The casing
11
is disposed in a vertical direction, and the flange
12
C at its lower end is integrally fixed to a reducer.
Furthermore, on the inner peripheral side, the main casing body
12
is provided with a couple of stepped portions
12
D and
12
E by which the inside diameter of the main casing body
12
is increased stepwise toward its open end. Provided on the stepped portion
12
are a large number of coupling grooves
12
F (only two of which are shown in the drawing) at intervals around the inner periphery or in the circumferential direction for engagement with non-rotating brake disks
23
which will be described hereinafter.
Indicated at
14
is an output shaft which is rotatably supported in the casing
11
. More specifically, the output shaft
14
is rotatably supported by the main casing body
12
through a bearing
14
A in the vicinity of its bottom portion
12
B and at the same time by the head casing
13
through a bearing
14
B.
Denoted at
15
is a cylinder block which is provided within the casing
11
. The cylinder block
15
is splined with and supported on the output shaft
14
. In this instance, a plural number of cylinders
16
are formed axially in the cylinder block
15
in angularly spaced positions around the circumference of the output shaft
14
. To and from the cylinder block
15
, operating oil is supplied from outside through inlet/outlet ports
18
A and
18
B, which will be described hereinafter, thereby to rotationally drive the output shaft
14
.
Indicated at
17
are, for example, nine arcuate grooves which are provided on the outer peripheral side of the cylinder block
15
. These arcuate grooves
17
are each in the form of a semi-circular groove which is extended in the axial direction of the cylinder block
15
and located substantially in equidistant positions around the circumference of the cylinder block
15
. In this instance, as shown in
FIG. 12
, the arcuate grooves
17
are formed in a predetermined radius of curvature R
1
which is, for example, approximately 10.00 mm.
Designated at
18
is a valve plate which is provided between the head casing
13
and the cylinder block
15
and fixed to the head casing
13
. This valve plate
18
is provided with a pair of inlet/outlet ports
18
A and
18
B which are intermittently communicated with the respective cylinders
16
of the cylinder block
15
. These inlet and outlet ports
18
A and
18
B are communicated with an oil supply passage (not shown) which is formed on the side of the head casing
13
.
Indicated at
19
are a plural number of pistons each having one end portion (an upper end portion) slidably fitted in a cylinder
16
of the cylinder block
15
and having the other end portion (a lower end portion) projected to the outside of the cylinder
16
. Each piston
19
is provided with a shoe
20
rockably at the projected lower end.
Denoted at
21
is a swash plate which is fixedly provided in the main casing body
12
. The pistons
19
are reciprocated into and out of the cylinders
16
as the shoes
20
of the respective pistons
19
are caused to slide on the upper side of the wash plate
21
.
Indicated at
22
is a negative type brake device which is provided for applying brakes to the output shaft
14
and the cylinder block
15
. This brake device
22
is constituted by non-rotating brake disks
23
, rotating brake disks
24
, a brake piston
27
and so forth, as described below.
Indicated at
23
are the non-rotating brake disks which are provided on the inner peripheral side of the main casing body
12
between the stepped portions
12
D and
12
E. These non-rotating brake disks
23
are each in the form of an annular disk using a friction material and, on the outer peripheral side, are engaged with the coupling grooves
12
F of the main casing body
12
. Consequently, the non-rotating brake disks
23
are axially movable relative to the main casing body
12
but blocked against rotation relative to the latter.
Designated at
24
are the rotating brake disks which are provided on the outer peripheral side of the cylinder block
15
. As shown in
FIG. 10
, the rotating brake disk
24
are each in the form of an annular disk using a friction material (lining), and are located on the outer peripheral side of the cylinder block
15
in an alternately overlapped state with the non-rotating brake disks
23
.
By way of arcuate projections
25
which will be described below, the rotating brake disks
24
are made movable in the axial direction relative to the cylinder block
15
, and can be brought into friction engagement with the non-rotating brake disks
23
to apply brakes to the cylinder block
15
in cooperation with the non-rotating brake disks
23
.
Indicated at
25
are nine arcuate projections which are provided on the inner peripheral side of each rotating brake disk
24
and projected radially inward in an arcuate shape, from uniformly spaced angular positions on the inner periphery of the rotating disk
24
. These arcuate projections
25
are engaged with the arcuate grooves
17
on the side of the cylinder block
15
to restrict movements of the rotating brake disks
24
in rotational directions relative to the cylinder block
15
.
In this instance, as shown in
FIG. 12
, the arcuate projections
25
are formed in a predetermined radius of curvature R
2
which is slightly smaller than the radius of curvature R
1
of the above-mentioned arcuate grooves
17
and which is, for example, approximately 9.75 mm.
Designated at
26
are nine grooves which are formed between adjacent arcuate projections
25
and are located in equidistant positions on the inner periphery of each rotating brake disk
24
alternately with the arcuate projections
25
.
Indicated at
27
is a brake piston which is axially slidably fitted in the main casing body
12
. This brake piston
27
is formed in a stepped cylindrical shape to define a liquid pressure chamber
28
in association with the stepped portion
12
E of the main casing body
12
. Further, under the influence of biasing action of a spring
29
, the brake piston
27
is constantly urged toward the non-rotating and rotating brake disks
23
and
24
. Consequently, the non-rota
Ino Kazuyuki
Satou Hitoshi
Takeuchi Yoshinori
Hitachi Construction Machinery Co. Ltd.
Mattingly Stanger & Malur, P.C.
Schwartz Christopher P.
Williams Thomas J.
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