Patent Application
20060118022
The present invention relates to a manual hydraulic steering apparatus having a steering wheel and a steering shaft that can be tilted up and down so that the wheel can be operated by an operator in an optimum position. More specifically, this invention relates to a tilting mechanism for a manual hydraulic steering apparatus for steering a vessel by means of a helm pump or another hydraulic pump that develops hydraulic steering force when the steering shaft of the apparatus is turned.
For example, FIGS. 1 and 2 of Japanese unexamined patent publication No. 2000-43794 show a steering apparatus including a hydraulic pump, a steering shaft and a tilting mechanism of the foregoing type. The tilting mechanism includes a joint coupling the steering shaft to the driving shaft of the pump tiltably in a vertical plane. The tilting mechanism and the adjacent end portion of the steering shaft are covered by a bellows cover in the form of a truncated cone, from which the other portion of this shaft protrudes. The steering apparatus is mounted on or in a vessel, with the body of the hydraulic pump extending through an opening in the dashboard of the vessel.
A major portion (the portion excluding the main unit) of the hydraulic pump and the tilting mechanism extend a large amount from the dashboard toward the stern. For this reason, they interfere with steering and are unpleasant in appearance. If a portion of the hydraulic pump and the tilting mechanism extend very greatly, they are not desirable for safety when the vessel collides, turns suddenly or stops suddenly.
FIG. 4 of the foregoing publication shows another steering apparatus as an art prior to the apparatus shown in FIGS. 1 and 2 of the publication publication. This steering apparatus includes a hydraulic pump and a tilting mechanism of the foregoing type. The tilting mechanism is separate from the hydraulic pump and includes a tilting shaft. The whole of the hydraulic pump is mounted inside the dashboard of a vessel. A mounting plate is fixed to the dashboard and has a central hole, through which the driving shaft of the hydraulic pump extends. The steering shaft is coupled to the outer end of the driving shaft. The tilting mechanism is fixed to the mounting plate.
Because this hydraulic pump, the mounting plate and this tilting mechanism are separate components, the mounting operation is complex and takes time. The hydraulic pump has an oil feeding port formed inside the dashboard. If an oil feeding passage connects the oil feeding port and the outside of the dashboard, extra parts are necessary for forming the passage. If there is no such passage, it takes time and/or is troublesome to supply oil to the oil feeding port, which is positioned inside the dashboard. It is necessary to periodically bleed the air accumulating near the oil feeding port. It takes time and/or is troublesome to bleed the air accumulating near the oil feeding port, which is positioned inside the dashboard.
The object of the present invention is to provide to a manual hydraulic steering apparatus that can be mounted on the dashboard of a vessel, the steering apparatus including a tilting mechanism not protruding greatly from the dashboard toward the stern, the tilting mechanism having an oil feeding port formed in the rear of the dashboard so that the oil feeding and air bleeding operations are easy, the tilting mechanism being able to be mounted on the dashboard relatively easily in a short time.
According to the present invention, a manual hydraulic steering apparatus is provided for a vessel, which is fitted with a dashboard having a first hole and a second hole both cut through it. The steering apparatus comprises a tilting mechanism positioned on one side of the dashboard and a hydraulic pump positioned on the other side. The tilting mechanism includes a mounting plate in contact with the dashboard. A tilt housing is fixed to the mounting plate and has an oil feeding tank formed in an upper portion thereof. The feeding tank has an oil feeding port, in which an oil plug fitted removably. A semispherical shell is supported turnably in all directions by the tilt housing. A steering shaft is supported rotatably by the semispherical shell. The hydraulic pump includes a pump casing, which has a mounting part extending into the first hole of the dashboard. An oil tank is provided in an upper portion of the hydraulic pump near the dashboard. A pumping mechanism is housed in the pump casing. A driving shaft is supported by the pump casing and rotatable so that the pumping mechanism can create hydraulic pressure for steering the vessel. The driving shaft extends through the mounting part of the pump casing and the mounting plate of the tilting mechanism. The mounting plate of the tilting mechanism is screwed to the mounting part of the pump casing. The steering shaft is coupled to the driving shaft rotatably with the driving shaft and tiltably on a horizontal axis perpendicular to the driving shaft. An oil feeding pipe extends through the second hole of the dashboard and communicates with the oil feeding tank and the oil tank.
The parts of the tilting mechanism that extend backward from the dashboard are a rear portion of the driving shaft, the tilt housing having an internal space for the semispherical shell, and the portion of the steering shaft that protrudes from this housing. These parts extend a considerably small amount as compared with a conventional steering apparatus including a hydraulic pump a major portion of which extends with a steering shaft backward from a dashboard. This prevents the tilting mechanism from interfering with steering. A steering wheel is fixed to the rear end of a conventional steering shaft, which extends a small amount backward. Accordingly, the steering wheel is very safe because the operator is not liable to hit on the wheel when the vessel turns suddenly or collides.
The oil feeding tank in the tilt housing communicates with the oil tank in the hydraulic pump. It is possible to feed oil and bleed air through the oil feeding port of the feeding tank, which is positioned in the rear of the dashboard. This makes the oil feeding and air bleeding operations easy.
It is possible to mount the tilting mechanism and the hydraulic pump on both sides of the dashboard simply, securely and firmly by inserting the mounting part of the pump casing into the first hole of the dashboard and connecting the mounting plate of the tilting mechanism to the mounting part.
The tilting mechanism may also include a generally spherical joint fixed to the adjacent end of the driving shaft and a bifurcated rotary driver fixed to one end of the steering shaft. The rotary driver is coupled to the generally spherical joint rotatably with it and turnably on the horizontal axis, on which the steering shaft can tilt. The semispherical shell has a central hole formed through it, in which the rotary driver and the steering shaft are supported rotatably. Preferably, the semispherical shell can be fixed to the tilt housing in an arbitrary position around the horizontal axis by a pair of pivot members, a clamping device or the like.
After the operator turns the steering shaft with the semispherical shell to an upper or lower optimum position relative to the driving shaft, he or she can fix the semispherical shell to the tilt housing by tightening the pivot members, the clamping device or the like. With the steering shaft angled in the optimum position, the steering wheel can be turned with the steering and driving shafts to drive the pumping mechanism, which creates steering force for the vessel.
The parts of the tilting mechanism that extend backward from the dashboard are reduced in size to a minimum, and the mechanism is small. As a result, the tilting mechanism does not interfere with steering, and is very safe in case the vessel is in a collision. The oil feeding port is positioned in the upper portion of the tilt housing in the rear of the dashboard, so that the oil feeding and air bleeding operations are easy. It is possible to mount the steering apparatus on the dashboard with comparative ease in a short time by positioning the tilting mechanism and the hydraulic pump on both sides of the dashboard and connecting the tilt housing and the pump casing together.
A preferred embodiment of the present invention is shown in the accompanying drawings, in which:
a is a rear end view of the tilting mechanism of the steering apparatus;
b is an axial section along line B-B of
c is part of
a is an axial section of the joint of the tilting mechanism, in section along line D-D of
b is a radial section along line C-C of
a is a rear view of the distributing valve of the helm pump of the steering apparatus;
b is an axial section of the distributing valve along line B-B of
c is a front view of the distributing valve.
With reference to
With reference to
A steering wheel (not shown) is fixed to the rear end of the steering shaft 5. The steering shaft 5 can rotate with a bifurcated rotary driver 6, which consists of a cylindrical hub 6a and a pair of arms 6b. The front end of the steering shaft 5 is inserted into the driver hub 6a and fixed to it with a spring pin 6d. The rotary driver 6 is coupled to the rear end of the driving shaft 53 by a generally spherical joint 7, which allows the rotary driver to rotate with the driving shaft and pivot or turn with respect to it. As shown in
As shown in
The tilt housing 2 has two tapped holes 2b cut through its side walls. The tapped holes 2b have a common axis extending horizontally through the center of the generally spherical joint 7 and radially of the driving shaft 53. Each of two tilt pins 4c has an external thread 4f cut between its head and bottom 4d. The external thread 4f engages with one of the housing holes 2b. The semispherical shell 4 has two pin holes 4b cut through it, which have a common axis extending radially of the steering shaft 5. The bottom of each tilt pin 4c engages loosely with one of the pin holes 4b of the semispherical shell 4. This allows the semispherical shell 4 to turn on the horizontal axis of the housing holes 2b.
After the operator tilts the steering shaft 5 up or down to an optimum position, the tilt pins 4c could be tightened to fix the semispherical shell 4. In this embodiment, however, the semispherical shell 4 can be fixed by a clamping device 15. As shown in
As shown in
As shown in
As shown in
The cylindrical part 52b of the pump casing 52 has tapped holes 52d cut in its rear end. The cylindrical hub 3a of the mounting plate 3 has bolt holes 3d cut through it. With the casing part 52b seated in the central recess 3b of the mounting plate 3, bolts 55 are put through the bolt holes 3d and engage with the tapped holes 52d. The rear wall 52a of the pump casing 52 has a hole 52c formed through its upper portion. Likewise, the mounting plate 3 has a hole formed through its upper portion. The front end of the feeding pipe 13 is fixed in the casing hole 52c. The rear end of the feeding pipe 13 is inserted into the hole of the mounting plate 3 and fixed in it when the bolts 55 are tightened. Thus, the helm pump 51 and tilting mechanism 1 are connected together inside and outside the dashboard D, respectively.
The helm pump 51 has a cylinder block 56 as the main part of a cylinder mechanism. The cylinder block 56 is coupled to a front end portion of the driving shaft 53 to turn with this shaft. The cylinder block 56 and driving shaft 53 are supported rotatably by a front bearing 57 and a rear bearing 57, respectively, which are fitted in the pump casing 52.
The cylinder block 56 has cylinders 58, which may be five, six or seven in number, formed at regular intervals around its axis. The cylinders 58 extend axially of the cylinder block 56, and each have an open top at its rear end and a closed bottom near its front end. A pumping piston 59 is in axially slidable engagement with each cylinder 58 and has a head 59a. The driving shaft 53 has a key groove 53a formed in it, with which a key 53b is in axially slidable engagement. A spring seat 61 in the form of a sleeve can slide axially on the driving shaft 53 and engages with the key 53b to turn with this shaft. The spring seat 61 has a semispherical surface adjacent to its rear end. An annular piston retainer 60 can slide in all directions on the semispherical surface and has U-shaped outer recesses 60a formed through it at regular intervals around its axis. Each recess 60a engages with one of the piston heads 59a. The pumping pistons 59 are biased backward by a coil spring 62, which surrounds the driving shaft 53 and is interposed between the spring seat 61 and the rear end of the cylinder block 56. Spacers 62a are is interposed between the coil spring 62 and the rear end of the cylinder block 56.
An inclined bracket 63 is fixed in the pump casing 52 and near its rear end, and supports an inclined ball bearing. The top of the ball bearing is backward of the bottom of this bearing. The ball bearing has a fixed race 65 and a rotating race 64. The piston heads 59a are in compressive contact with the rotating race 64. When the driving shaft 53 turns with the cylinder block 56, pumping pistons 59 and piston retainer 60, the pistons 59 reciprocate axially.
The cylinder block 56 has oil passages 58a formed through it, each of which extends between the bottom of one of the cylinders 58 and the front end of the cylinder block 56. The pump casing 52 has a front central hole 52d formed through it, in which a distributing valve 66 in the form of a disc is fitted. As best shown in
A cylindrical end block 71 is bolted to the front end of the pump casing 52. The end block 71 has a pair of larger recesses 72 formed on its rear side diametrically opposite each other and a pair of smaller recesses 73 formed on this side diametrically opposite each other. Each larger recess 72 is positioned at a right angle from each smaller recess 73 around the axis of the end block 71. The front cylindrical part 69b of each pressing piston 69 is inserted into one of the larger recesses 72, with an O-ring 69e interposed between the piston 69 and end block 71. The end block 71 also has a pair of inlet/outlet ports 74 formed on its front side diametrically opposite each other. Each inlet/outlet port 74 communicates with one of the larger recesses 72 by means of an oil passage 75. A spring seat 76 is put slidably in each smaller recess 73. The front end of one of the coil springs 70 is in contact with the spring seat 76 to bias the distributing valve 66 backward. The end block 71 further has a pair of tapped holes 78 formed through it, each of which extends between the front ends of the end block 71 and one of the smaller recesses 73. An adjusting bolt 77 engages with each tapped hole 78. The rear end of the adjusting bolt 77 is in contact with the associated seat 76. The rotation of the adjusting bolt 77 adjusts the force of the associated spring 70. A fixing nut 79 engages with the adjusting bolt 77 and can be tightened to fix it.
As is the case with the conventional helm pumps, when the driving shaft 53 turns in one direction with the steering shaft 5, the cylinder block 56 turns to reciprocate the pumping pistons 59 axially. This causes pressure oil to be discharged from the helm pump 51 through one of the inlet/outlet ports 74 and sucked through the other into the pump.
While the helm pump 51 is operating, a hydraulic discharge pressure is applied on the rear end of the smaller cylindrical part 69a of one of the pressing pistons 69, and a hydraulic suction pressure is applied on the front end of the larger cylindrical part 69bof the other piston. Because the hydraulic pressures per unit area on the cylindrical parts 69a and 69b are equal, the suction pressure on the front end of the larger part 69b prevails over the discharge pressure on the rear end of the smaller part 69a, which is smaller in area than the front end. As a result, the distributing valve 66 is biased backward against the front end of the cylinder block 56.
While the steering shaft 5 is not turned, so that the helm pump 51 is not operating, no hydraulic pressure is applied on the pressing pistons 69. The coil springs 70 exert a relatively weak force on the distributing valve 66 to bias it backward against the front end of the cylinder block 56.
Thus, the helm pump 51 circulates the hydraulic oil in the steering apparatus by discharging part of the oil through one of the inlet/outlet ports 74 into the main unit (not shown) of the steering apparatus and sucking the other part of the oil from this unit through the other port to steer the vessel.
The pumping pistons 59 are biased backward at the same time by the single spring 62 and single retainer 60. The piston heads 59a engage with the retainer recesses 60a. Thus, the helm pump 51 requires only one coil spring for the pumping pistons 59 and is consequently simple in structure. There is no need to cut a spring hole for engaging with a coil spring in the body of each pumping piston 59. Air may accumulate in the spring holes in the pistons of the hydraulic pump of a conventional steering apparatus. The air accumulation may cause the discharge pressure of the hydraulic pump to act intermittently on the steering apparatus while the apparatus is operating. The pumping pistons 59 of the helm pump 51 have no such spring holes, where air might accumulate.
In a conventional hydraulic pump, a distributing valve is screwed to the rear end surface of its end block. The front end surface of the cylinder block of this pump, the front and rear surfaces of this valve, and the rear end surface of this block need finishing with very high accuracy to prevent oil leakage. The distributing valve 66 of the helm pump 51 is floating and biased against the front end of the cylinder block 56 by the hydraulic pressure created while the pump is operating, and by the auxiliary spring force. As a result, even if the distributing valve 66 etc. are finished with lower accuracy, oil leakage can be prevented reliably. This makes it possible to produce the pump more easily at lower cost.
As stated already, the oil feeding pipe 13 communicates with the top of the oil tank 54 in the helm pump 51. It is easy to feed the oil tank 54 with oil through the feeding pipe 13 from the oil feeding port 12a in the tilt housing 2. The oil feeding tank 11 in the tilt housing 2 communicates with the top of the oil tank 54 by means of the feeding pipe 13. Naturally, the air in the pump casing 52 moves to and accumulates in an upper portion of the feeding tank 11. This makes it possible to bleed air from the feeding port 12a by removing the oil plug 12.
The steering shaft 5 is supported tiltably on a horizontal axis by the tilt housing 2 as a main part of the tilting mechanism 1. The tilt housing 2 is simple in structure, having the oil feeding tank 11, the oil plug 12 and a means for coupling the steering shaft 5 to the rear portion 53A of the driving shaft 53. Accordingly, the tilt housing 2 is so compact that the distance between its rear end and the dashboard D can be shortened to a minimum. As a result, the tilt housing 2 as mounted on the dashboard D does not interfere with steering.
The pump casing 52 and tilt housing 2 are positioned on both sides of the dashboard D and can be mounted to it by being connected together. Accordingly, the pump casing 52 and tilt housing 2 can be mounted simply and securely by a small number of parts.
The helm pump 51 might be replaced by a conventional or general helm pump, or another hydraulic pump.
