Information
-
Patent Grant
-
6280268
-
Patent Number
6,280,268
-
Date Filed
Thursday, March 16, 200024 years ago
-
Date Issued
Tuesday, August 28, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 188 318
- 188 275
- 188 32222
- 440 61
-
International Classifications
-
Abstract
A tilt device for a marine propulsion unit is disclosed where a shock blow valve comprises a disk valve fixed to a valve seat surface of the piston, the valve seat surface being provided with a seal member surrounding a communication hole which opens at the valve seat surface, and the disk valve is tightly connected to the seal member.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a tilt device for a marine propulsion unit.
2. Description of the Related Art
There exists a conventional tilt device for a marine propulsion unit in which a cylinder device is interposed between a stern bracket fixed to a boat body and a swivel bracket which supports a propulsion unit. An interior of the cylinder device is divided into a first tilt chamber closer to a side in which a piston rod is accommodated and a second tilt chamber closer to a side in which the piston rod is not accommodated by means of a piston. The tilt device includes a shock blow valve which makes it possible to expand the piston rod by sending oil in the first tilt chamber to the second tilt chamber through a communication hole formed in the piston which is opened and closed with a constant set pressure. In this prior art, when the marine propulsion unit collides against a floating log or the like, the shock blow valve is opened to turn up the propulsion unit, thereby absorbing the impact force.
In the prior art, the shock blow valve comprises a ball for sitting on a valve seat provided around the communication hole of the piston thereby closing the communication hole, and a spring for biasing the ball against the valve seat. The prior art has the following problems 1) to 3).
1) In the case of the shock blow valve using the ball, it takes time to completely close the communication hole after the hole is once opened, and the response is slow. This is because it takes time to obtain a sitting attitude of the ball, having critical clearance tolerances, with the result that the ball completely conforms to the valve seat with difficulty.
2) The setting of the valve opening pressure is difficult due to variation of the spring constant.
3) The ball and the spring occupy constant space in a thickness direction of the piston, and this fact increases the thickness of the piston. As a result, even if the cylinder's length is the same, a piston stroke in the cylinder is shortened.
SUMMARY OF THE INVENTION
It is an object of the present invention to quicken the response of a shock hollow valve of a tilt device for a marine propulsion unit, to facilitate fine adjustment of valve opening pressure, to reduce thickness of a piston, and to increase a piston stroke in a cylinder having the same length as much as possible.
According to the present invention, there is disclosed a tilt device for a marine propulsion unit in which a cylinder device is interposed between a stern bracket fixed to a boat body and a swivel bracket which supports a propulsion unit. The cylinder device is divided into a first tilt chamber closer to a side in which a piston rod is accommodated and a second tilt chamber closer to a side in which the piston rod is not accommodated by means of a piston fixed to the piston rod. The tilt device includes a shock blow valve which makes it possible to expand the piston rod by sending oil in the first tilt chamber to the second tilt chamber through a communication hole formed in the piston which is opened and closed with a constant set pressure. The shock blow valve comprises a disk valve fixed to a valve seat surface of the piston, the valve seat surface being provided with a seal member surrounding a communication hole which opens at the valve seat surface. The disk valve is tightly connected to the seal member.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be more fully understood from the detailed description given below and from the accompanying drawings which should not be taken to be a limitation on the invention, but are for explanation and understanding only.
The drawings
FIG. 1
is a schematic view showing a marine propulsion unit;
FIG. 2
is a side view showing a layout of a stern bracket, a swivel bracket and a power unit;
FIG. 3
is a front view showing the layout of the stern bracket, the swivel bracket and the power unit;
FIG. 4
is a front view, partly in section, of the power unit;
FIG. 5
is a side view of
FIG. 4
;
FIG. 6
is a circuit diagram showing a hydraulic pressure circuit;
FIG. 7
is a sectional view showing a shock blow valve of a first embodiment;
FIGS. 8 and 9
show a seal member provided on a piston, wherein
FIG. 8
is a sectional view of the entire seal member, and
FIG. 9
is a sectional view of an essential portion of the seal member;
FIGS. 10
to
12
show the seal member provided on the piston, wherein
FIG. 10
is a plan view of the entire seal member,
FIG. 11
is a plan view of an essential portion of the seal member, and
FIG. 12
is a sectional view taken along the line C—C;
FIGS. 13 and 14
show a seal member provided on a piston in a shock blow valve of a second embodiment, wherein
FIG. 13
is a sectional view of the entire seal member, and
FIG. 14
is a sectional view of an essential portion of the seal member; and
FIGS. 15
to
17
show the seal member provided on the piston, wherein
FIG. 15
is a plan view of the entire seal member,
FIG. 16
is a plan view of an essential portion of the seal member, and
FIG. 17
is a sectional view taken along the line C—C.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in
FIG. 1
to
FIG. 3
, a marine propulsion unit
10
(it may be an outboard motor or an inboard motor) is provided with a stern bracket
12
secured to a stern plate
11
A of a boat body
11
. And a swivel bracket
14
is pivotally connected to the stern bracket
12
through a tilt shaft
13
such that the swivel bracket
14
can tilt around a substantially horizontal axis. A propelling unit
15
is pivotally connected to a swivel bracket
14
through a steering shaft which is not shown and is substantially vertically disposed such that the propelling unit
15
can be turned around the steering shaft. An engine unit
16
is mounted in an upper portion of the propelling unit
15
, and the propelling unit
15
is provided at its lower portion with a propeller
17
.
The propelling unit
15
of the marine propulsion unit
10
is pivotally supported on the stern bracket
12
secured to the boat body
11
through the tilt shaft
13
and the swivel bracket
14
. A cylindrical device
21
of a power unit
20
A constituting the tilt device
20
is interposed between the stern bracket
12
and the swivel bracket
14
. And a hydraulic fluid is selectively supplied or discharged from or into a hydraulic fluid supply/discharge device
22
of the power unit
20
A into or from the cylinder device
21
, thereby expanding or contracting the cylinder device
21
so that propelling unit
15
can be tilted.
(Cylinder device
21
) (
FIG. 4
)
The cylinder device
21
of the power unit
20
A constituting the tilt device
20
is integrally coupled to a valve block
65
, which will be described later, in a hydraulic fluid supply/discharge device
22
. The cylinder device
21
includes an outer cylinder
31
and an inner cylinder
32
which may be steel pipes formed by drawing molding. These cylinders
31
and
32
are integrally coupled to the valve block
65
. The valve block
65
, which may be a cast aluminum alloy for example, includes a mounting pin insertion hole
65
A for the stern bracket
12
.
The cylinder device
21
includes a piston rod
33
which is connected to the swivel bracket
14
. The piston rod
33
is inserted through a rod guide
34
provided at an open end of the outer cylinder
31
and into a tilt chamber
35
of the inner cylinder
32
such that the piston rod
33
can be extended and contracted. The rod guide
34
includes a seal member
36
which slidably engages the piston rod
33
. The piston rod
33
includes a mounting pin insertion hole
33
A for the swivel bracket
14
.
Cylinder device
21
includes a piston
39
secured to an end of the piston rod
33
in the tilt chamber
35
of the inner cylindrical
32
by a nut
38
. The piston
39
includes a seal member
41
such as an O-ring or the like which is slidably in contact with the inner surface of the inner cylinder
32
, and divides the tilt chamber
35
into a first tilt chamber
35
A which accommodates the piston rod
33
and a second tilt chamber
35
B which does not accommodate the piston rod
33
.
The cylinder device
21
includes a large diameter hole
42
A, an intermediate diameter hole
42
B and a small diameter hole
42
C which are concentric with the valve block
65
, and a large diameter portion
43
A and a small diameter portion
43
C which are concentric with the rod guide
34
. One end of the outer cylinder
31
is fitted to the large diameter hole
42
A of the valve block
65
through a seal member
44
such as an O-ring, and the other end of the outer cylinder
31
is fitted to the large diameter portion
43
A of the rod guide
34
and is secured by a bent portion
46
. One end of the inner cylinder
32
is fitted to the small diameter hole
42
C of the valve block
65
through a seal member
47
such as an O-ring, and the other end of the inner cylinder
32
is fitted to and secured to the small diameter portion
43
C of the rod guide
34
. With this structure, a ring space-like oil passage
48
is formed between the outer cylinder
31
and the inner cylinder
32
, and the first tilt chamber
35
A and the oil passage
48
are interconnected through an oil passage
49
which opens at the inner cylinder
32
(or a communicating passage
49
A which opens at the rod guige
34
). The oil passage
48
which is in communication with the first tilt chamber
35
A interconnects with a first oil passage
66
A which is in communication with the intermediate diameter hole
42
B of the valve block
65
, and the second tilt chamber
35
B is connected with a second oil passage
66
B provided in the valve block
65
respectively.
The piston
39
of the cylinder device
21
includes a shock blow valve
50
which opens at a set pressure to protect a hydraulic pressure circuit when an impact force is applied in an extension direction of the cylinder device
21
, such as when a floating log collides against the propelling unit
15
. The hydraulic fluid in the first tilt chamber
35
A is transferred to the second tilt chamber
35
B so that the piston rod
33
can be extended.
Next, a structure for coupling the cylinder device
21
to the valve block
65
will be explained.
(1) The large diameter hole
42
A of the valve block
65
is provided with a ring groove
51
having an arc or square section. One end of the outer cylinder
31
is inserted into the large diameter hole
42
A, one end of the outer cylinder
31
being bulged or distended outwardly by a bulge process to form a bulge portion
52
, the bulge portion
52
being engaged with the above-described ring groove
51
. The bulge process is conducted, for example, by pressing a resilient member such as a urethane insert into the outer cylinder
31
by the pressuring piston (this can also be done by pressing a liquid charged in the outer cylinder
31
, or by enlarging a diameter of a division ring inserted in the outer cylinder
31
), so that the outer cylinder
31
is deformed or distended to follow the ring groove
51
of a valve block
65
.
(2) An assembly of the inner cylinder
32
is inserted into the outer cylinder
31
which is secured to the valve block
65
by the above process (1), and one end of the inner cylinder
32
is fitted to the small diameter hole
42
C of the valve block
65
. The assembly of the inner cylinder
32
comprises the piston
39
, the piston rod
33
, and the rod guide
34
or the like, which have been previously assembled into the inner cylinder
32
before the inner cylinder
32
is inserted into the outer cylinder
31
.
(3) A bent portion
46
at the other end of the outer cylinder
31
is secured around the rod guide
34
of the assembly of the inner cylinder
32
.
The Hydraulic fluid supply/discharge device
22
, as shown in
FIGS. 4 and 5
, is next described.
The hydraulic fluid supply/discharge device
22
of the power unit
20
A constituting the tilt device
20
comprises a reversible motor
61
, a reversible gear pump
62
and a tank
63
, and a switching valve
64
, which can supply and discharge a hydraulic fluid to and from the first tilt chamber
35
A and the second tilt chamber
35
B of the cylinder
21
through the first oil passage
66
A and the second oil passage
66
B provided in the valve block
65
.
At that time, the hydraulic fluid supply/discharge device
22
forms a passage having a switch valve
64
on the valve block
65
formed of cast aluminum alloy, and includes the first oil passage
66
A, and the second oil passage
66
B. The valve block
65
includes a large diameter block
42
A, an intermediate diameter hole
42
B and a small diameter hole
42
C for integrally forming the cylinder device
21
as described above, and includes a pump chamber
67
at a location adjacent to an integrally coupled portion of the cylinder device
21
. The pump chamber
67
accommodates the hydraulic fluid, and includes the pump
62
in a state where the pump
62
soaks in the hydraulic fluid. The pump
62
is secured to the valve block
65
through a bolt
68
.
The hydraulic fluid supply/discharge device
22
includes a motor
61
which drives the pump
62
and which is disposed on an upper portion of the pump chamber
67
provided in the valve block
65
, and the tank
63
comprises a tank housing
74
for covering the motor
61
. The motor
61
comprises an iron yoke
70
, and an end plate
72
connected in a water-tight manner to a lower opening end of the yoke
70
through a seal member such as an O-ring, which is secured thereto by a setscrew. The end plate
72
is provided at its upper and lower sides with upper and lower steps
72
A and
72
B, respectively. A periphery portion of the pump chamber
67
of the valve block
65
is fitted to the lower step
72
B and is connected in a water-tight manner with an O-ring
83
. The tank bushing
74
is fitted to the upper step
72
A and is connected in a water-tight manner with an O-ring
81
. The tank housing
74
and the end plate
72
are fastened to the valve block
65
by a bolt
73
. Details thereof are described below.
The hydraulic fluid supply/discharge device
22
secures mounting portions
70
B for mounting a seat
70
A of the iron yoke
70
of the motor
61
to an end plate
72
, which may be made of synthetic resin, for the motor
61
, by setscrews
71
. A lead wire
61
L of the motor
61
is pulled out from a side of the end plate
72
. The end plate
72
of the motor
61
is secured around the pump chamber
67
of the valve block
65
together with the mounting portion
74
B of the mounting seat
74
A of the tank housing
74
by a bolt
73
, to seal the pump chamber
67
. An output shaft
61
A of the motor
61
is passed through the end plate
72
in a water-tight manner and is connected to a follower shaft of the pump
62
.
The hydraulic fluid supply/discharge device
22
covers the yoke
70
of the motor
61
with the tank housing
74
which may be made of synthetic resin and having a cylindrical shape and may have a ceiling corresponding to the outline of the yoke
70
of the motor
61
. The tank housing
74
is secured to the valve block
65
together with the end plate
72
of the motor
61
by the bolt
73
to constitute the tank
63
. A space between the tank housing
74
and the yoke
70
of the motor
61
is defined as the tank chamber
75
.
In the tilt device
20
, as shown in
FIGS. 1
to
3
, when the power unit
20
A is interposed between the stern bracket
12
and the swivel bracket
14
as described above, as shown in
FIGS. 4 and 5
, a chamfered portion
76
is formed on an upper portion of the tank housing
74
of the tank
63
constituting the power unit
20
A, the chamfered portion
76
being formed on the upper portion of the tank housing
74
on the side facing the swivel bracket
14
. The chamfered portion
76
is provided with an oil pouring hole
77
, and a cap
78
is mounted to the oil poring hole
77
. A chamfering angle θ of the chamfered portion
76
with respect to an upper surface of the tank housing
74
is 45°, for example.
The hydraulic fluid supply/discharge device
22
further includes a shuttle type switch valve
91
, check valves
92
,
93
, a contraction-side relief valve
94
, a manual-thermal valve
95
and an extension-side relief valve
96
.
The shuttle type switch valve
91
includes a shuttle piston
101
, and first and second check valves
102
A and
102
B disposed on opposite sides of the shuttle piston
101
. A first shuttle chamber
103
A is defined in the shuttle piston
101
at the side of the first check valve
102
A, and a second shuttle chamber
103
B is defined in the shuttle piston
101
at the side of the second check valve
102
B. The first check valve
102
B is opened by hydraulic pressure applied to the first shuttle chamber
103
A, by the normal rotation of the pump
62
, through a pipe
64
, and the second check valve
102
B is opened by hydraulic pressure applied to the second shuttle chamber
103
B, by the reverse rotation of the pump
62
, through a pipe
64
. The shuttle piston
101
opens the second check valve
102
B by hydraulic pressure by the normal rotation of the pump
62
, and opens the first check valve
102
A by the hydraulic pressure by the reverse rotation of the pump
62
. The first check valve
102
A of the shuttle type switch valve
101
is connected to the first oil passage
66
A, and the second check valve
102
B is connected to the second oil passage
66
B.
A check valve
92
is interposed in an intermediate portion of a connection pipe connecting the pump
62
and the tank
63
. More specifically, during tilt up operation of the marine propulsion device
10
, the volume in the cylinder
32
is increased by a displaced volume of the retreated piston rod
33
and an amount of circulating hydraulic fluid which is running short. Therefore, the check valve
92
is opened so that the deficiency can be compensated to the pump
62
from the tank
63
.
A check valve
93
is interposed in an intermediate portion of a connection pipe connecting the pump
62
and the tank
63
. More specifically, during the tilt down operation of the marine propulsion device
10
, when the piston
39
reaches the maximum contraction position, the tilt down operation has been completed, and there is no hydraulic fluid returning from the second tilt chamber
35
B to the pump
62
, if the pump
62
is further operated, the check valve
93
is opened so that hydraulic fluid can be supplied from the tank
63
to the pump
62
.
The contraction-side relief valve
94
is connected to the pipe
64
. In order to return to the tank
63
, the hydraulic fluid for the rod which remains at the time of the tilt down operation, and in order to protect the hydraulic circuit when the pump
62
is further operated even if the tilt down operations have been completed, the pressure in the circuit is released to the tank
63
if the pressure reaches a set pressure.
An extending-side relief valve
96
is embedded in a shuttle piston
101
for releasing circuit pressure toward a pump suction side at a set pressure so as to protect the hydraulic pressure circuit when the pump
62
continues to be operated after the tilting up operation is completed.
Where the manual-thermal valve
95
is connected to the second oil passage
66
B, the cylinder device
21
may be manually contracted by connecting the second-tilt chamber
35
B to the tank
63
, so that the propulsion unit
15
can trim down and tilt down. The manual-thermal valve
95
includes a thermal relieve valve
95
A so that when pressure in the hydraulic fluid of the cylinder
21
is abnormally increased due to a heat, the pressure in the circuit is released to the tank
63
if the pressure reaches a set pressure.
The basic operation of the tilt device
20
will be explained below.
(1) Tilt down
When the motor
61
and the pump
62
are normally rotated, the discharged oil from the pump
62
opens the first check valve
102
A of the shuttle type switch valve
91
, and also opens the second check valve
102
B through the shuttle piston
101
. In this mode of operation, the discharged oil from the pump
62
passes through the first check valve
102
A and the first oil passage
66
A and is supplied into the first tilt chamber
35
A of the cylinder device
21
. The hydraulic fluid in the second tilt chamber
35
B of the cylinder device
21
passes through the second oil passage
66
B of the second check valve
102
B and returns to the pump
62
to contract the cylinder device
21
so that the cylinder device
21
is tilted down.
(2) Tilt up
When the motor
61
and the pump
62
are rotated in reverse, the discharged oil from the pump
62
opens the second check valve
102
B of the shuttle type switch valve
91
, and also opens the first check valve
102
A through the shuttle piston
101
. In this mode of operation, the discharged oil from the pump
62
passes through the second check valve
102
B and the second oil passage
66
B and is supplied to the second tilt chamber
35
B of the cylinder device
21
, and the hydraulic fluid in the first tilt chamber
35
A of the cylinder device
21
passes through the first oil passage
66
A and the first check valve
102
A and returns to the pump
62
to expand the cylinder device
21
so that the cylinder device
21
is tilted up.
(3) When the marine propulsion unit collides against a floating log or the like, and the propulsion unit
15
of the marine propulsion unit
10
collides against the obstacle during forward running, pressure in the first tilt chamber
35
A is abnormally increased due to the impact force so that the shock blow valve
50
is opened, the oil in the first tilt chamber
35
A is sent to the second tilt chamber
35
B, the piston rod
33
extends with respect to the cylinder
32
, and the propulsion unit
15
is turned up, thereby absorbing the impact.
The First Embodiment, as shown in
FIGS. 7
to
12
, is next disclosed.
In the cylinder device
21
of the tilt device
20
, the shock blow valve
50
is structural in the following manner. As shown in
FIGS. 7
to
9
C, in the cylinder device
21
, a washer
111
, the piston
39
, a disk valve
112
and a valve stopper
113
are sandwiched between the end of the piston rod
33
and a nut
38
. The disk valve
112
fixed to a valve seat surface
39
A of the piston
39
constitutes the shock blow valve
50
. A seal member
115
is provided such as to surround the communication hole
114
between the first chamber
35
A and the second tilt chamber
35
B, and the disk valve
112
is tightly connected to the seal member
115
. With this arrangement, the shock blow valve
50
opens and closes the communication hole
114
at a given set pressure determined by the number of laminated layers of the disk valve
112
, or by a diameter of the valve stopper
113
, so that the oil in the first tilt chamber
35
A is sent to the second tilt chamber
35
B, thereby allowing the piston rod
33
to extend.
In one embodiment, the piston
39
includes a plurality of communication holes
114
, and a single annular seat member
115
which collectively surround all of the communication holes
114
(FIGS.
8
and
10
). The valve seat surface
39
A of the piston
39
is formed with a single annular holding groove
116
of the seal member
115
. An injection forming flowing groove
117
is formed in each of a plurality of positions of an inner periphery of the holding groove
116
in its circumferential direction (
FIGS. 10
to
12
). With this arrangement, an injection mold (not shown) is put on the valve seat surface
39
A of the piston
39
, an injection nozzle of the mold is fitted to the flowing groove
117
, and in this state, molten material such as rubber is allowed to flow into the holding groove
116
, thereby baking and adhering the seal member
115
to the holding groove
116
(cure adhesion by injection). In
FIGS. 10 and 11
, the symbol
117
A represents a nozzle hole mark (trace) of the injection nozzle.
In the shock blow valve
50
, as shown in
FIG. 9
, an outer peripheral portion
118
of the valve seat surface
39
A of the piston
39
is formed slightly higher than an inner peripheral portion
118
B (step h) so that a preset load is applied to the disk valve
112
. With this arrangement, the disk valve
112
is bent and mounted upon the valve seat surface
39
A of the piston
39
to apply the preset load. If the preset load is applied to the disk valve
112
, the response speed thereof from the time when the valve
112
is first opened to the time when the valve is closed is high, so that the response can be further quickened.
The seal member
115
formed in the holding groove
116
provided in the valve seat surface
39
A of the piston
39
is formed such that in the holding groove
116
of rectangular cross section, a central portion of the seal member
115
is formed with a projection
115
A, and opposite sides of the projection
115
A are formed with recesses
115
B and
115
B.
Therefore, the following effect can be obtained by the present embodiment.
1) The valve seat surface
39
A of the piston
39
is provided with the seal member
115
, and the disk valve
112
constituting the shock blow valve
50
is tightly connected to the seal member
115
. With this arrangement, the shock blow valve
50
is tightly closed immediately when the disk valve
112
is brought into contact with the seal member
115
. The response speed thereof from the time when the valve
112
is once opened to the time when the valve is closed is shortly, so that the response can be further quickened.
2) A valve opening pressure of the shock blow valve
50
can be adjusted by the number of laminated layers of the disk valve
112
fixed to the valve seat surface
39
A of the piston
39
, and the valve opening pressure can thereby be set finely. The valve opening pressure can also be adjusted by varying the diameter of the valve stopper
113
.
3) The space occupied by the disk valve
112
and the seal member
115
constituting the shock blow valve
50
in the thickness direction of the piston
39
may be small, the thickness of the piston
39
may be reduced, and the piston stroke can be increased to the utmost in the cylinder having the same length, as much as possible. Further, if the piston stroke is the same, it is possible to shorten the length of the cylinder, and the cylinder can be made compact.
4) Of the disk valve
112
and the seal member
115
constituting the shock blow valve
50
, when the seal member
115
is formed integrally with the valve seat surface
39
A of the piston
39
by the adhesive, it is possible to reduce the number of parts of the assembly and the number of assembling steps.
5) When the shock blow valve
50
includes the single seal members
115
which collectively surround all the communication holes
114
, the pressure receiving area of the disk valve
112
divided by the seal member
115
is increased, the valve can be opened with relatively low pressure, and the valve opening pressure can be reduced.
6) Where the shock blow valve
50
is constituted such that the seal member
115
is adhered to the holding groove
116
formed in the valve seat surface
39
A of the piston
39
, it is possible to reduce the number of parts of the assembly and the number of assembling steps.
7) Where the shock blow valve
50
is constituted such that the seal member
115
is injection molded to the holding groove
116
formed in the valve seat surface
39
A of the piston
39
, it is possible to reduce the number of parts of the assembly and the number of assembling steps.
The Second Embodiment, as shown in
FIGS. 13
to
17
, is next described.
In the second embodiment also, like the first embodiment, the shock blow valve
50
is constituted by the disk valve
112
being fixed to the valve seat surface
39
A of the piston
39
, the seal member
121
being arranged to surround the communication hole
114
opening at the valve seat surface
39
A, and the disk valve
112
, is arranged to tightly connect to the seal member
121
. With this arrangement, the shock blow valve
50
opens and closes the communication hole
114
at a given set pressure determined by the number of laminated layers of the disk valve
112
, or by a diameter of the valve stopper
113
, so that the oil in the first tilt chamber
35
A is sent to the second tilt chamber
35
B, thereby allowing the piston rod
33
to extend.
At that time, the piston
39
includes a plurality of communication holes
114
, and includes small annular seal members
121
each surrounding each of the communication holes
114
(
FIGS. 13
,
15
and
16
). Annular holding grooves
122
are formed in the valve seat surface
39
A of the piston
39
around each of the communication holes
114
, and injection forming flowing groove
123
is auxiliary formed in a side of each of the holding grooves
122
(two locations in the diametric direction) (FIGS.
16
and
17
). With this arrangement, an injection mold (not shown) is put on the valve seat surface
39
A of the piston
39
, an injection nozzle of the mold is fitted to the flowing groove
123
, and in this state, molten material such as rubber is allowed to flow into the holding groove
122
, thereby baking and adhering the seal member
121
to the holding groove
122
(cure adhesion by injection). In
FIGS. 15 and 16
, the symbol
123
A represents a nozzle hole mark (trace).
The seal member
121
formed in the holding groove
122
provided in the valve seat surface
39
A of the piston
39
is formed such that in the holding groove
122
of rectangular cross section, a central portion of the seal member
121
is formed with a projection
121
A, and opposite sides of the projection
121
A are formed with recesses
121
B and
121
B.
According to the present embodiment, the same effects as 1) to 4), 6) and 7) in the first embodiment can be obtained.
As heretofore explained, embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configurations of the present invention are not limited to the embodiments but those having a modification of the design within the range of the present invention are also included in the present invention.
According to the present invention, in a shock blow valve of a tilt device for a marine propulsion unit, it is possible to quicken response of the valve, to finely set valve opening pressure, to reduce thickness of a piston, and to increase a piston stroke in a cylinder having the same length, as much as possible. Alternatively, if the piston stroke is the same, it is possible to shorten the length of the cylinder, and the cylinder can be made compact.
Although the invention has been illustrated and described with respect to several exemplary embodiments thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions and additions may be made to the present invention without departing from the spirit and scope thereof. Therefore, the present invention should not be understood as limited to the specific embodiment set out above, but should be understood to include all possible embodiments which can be embodied within a scope encompassed and equivalents thereof with respect to the features set out in the appended claims.
Claims
- 1. A tilt device for a marine propulsion unit in which a cylinder device is interposed between a stern bracket fixed to a boat body and a swivel bracket which supports a propulsion unit, the cylinder device is divided into a first tilt chamber closer to a side in which a piston rod is accommodated and a second tilt chamber closer to a side in which the piston rod is not accommodated by means of a piston fixed to a piston rod, and the tilt device includes a shock blow valve which makes it possible to expand the piston rod by sending oil in the first tilt chamber to the second tilt chamber through a communication hole formed in the piston which is opened and closed with a constant set pressure, whereinthe shock blow valve comprises a disk valve fixed to a valve seat surface of the piston, the valve seat surface is provided with a seal member surrounding a communication hole which opens at the valve seat surface, and the disk valve is tightly connected to the seal member; a holding groove of the seal member is formed in the valve seat surface of the piston, and the seal member is adhered to the holding groove; the holding groove formed in the valve seat surface of the piston auxiliary includes a flowing groove for inject-forming the seal member.
- 2. A tilt device for a marine propulsion unit in which a cylinder device is interposed between a stern bracket fixed to a boat body and a swivel bracket which supports a propulsion unit, the cylinder device is divided into a first tilt chamber closer to a side in which a piston rod is accommodated and a second tilt chamber closer to a side in which the piston rod is not accommodated by means of a piston fixed to a piston rod, and the tilt device includes a shock blow valve which makes it possible to expand the piston rod by sending oil in the first tilt chamber to the second tilt chamber through a communication hole formed in the piston which is opened and closed with a constant set pressure, whereinthe shock blow valve comprises a disk valve fixed to a valve seat surface of the piston, the valve seat surface is provided with a seal member surrounding a communication hole which opens at the valve seat surface, and the disk valve is tightly connected to the seal member; the piston includes a plurality of communication holes, the tilt device further comprises a single seal member which collectively surrounds all of the communication holes; a holding groove of the seal member is formed in the valve seat surface of the piston, and the seal member is adhered to the holding groove; the holding groove formed in the valve seat surface of the piston auxiliary includes a flowing groove for inject-forming the seal member.
- 3. A tilt device for a marine propulsion unit in which a cylinder device is interposed between a stern bracket fixed to a boat body and a swivel bracket which supports a propulsion unit, the cylinder device is divided into a first tilt chamber closer to a side in which a piston rod is accommodated and a second tilt chamber closer to a side in which the piston rod is not accommodated by means of a piston fixed to a piston rod, and the tilt device includes a shock blow valve which makes it possible to expand the piston rod by sending oil in the first tilt chamber to the second tilt chamber through a communication hole formed in the piston which is opened and closed with a constant set pressure, whereinthe shock blow valve comprises a disk valve fixed to a valve seat surface of the piston, the valve seat surface is provided with a seal member surrounding a communication hole which opens at the valve seat surface, and the disk valve is tightly connected to the seal member, the piston includes a plurality of communication holes, the tilt device further comprises a plurality of seal members each of which surrounds each of the communication holes; a holding groove of the seal member is formed in the valve seat surface of the piston, and the seal member is adhered to the holding groove; the holding groove formed in the valve seat surface of the piston auxiliary includes a flowing groove for inject-forming the seal member.
Priority Claims (1)
Number |
Date |
Country |
Kind |
11-076789 |
Mar 1999 |
JP |
|
US Referenced Citations (3)
Foreign Referenced Citations (1)
Number |
Date |
Country |
86715 |
Feb 1996 |
JP |