Patent Application
20200361586
This application is based upon and claims the benefit of priority to Japanese patent application No. 2019-091620, filed on May 14, 2019, the entire contents of which are incorporated herein by reference.
The present invention relates to a steering device and a watercraft steering device.
In the related art, steering devices are available and used in various fields. For example, a power tilt and power steering device provided with a power tilt hydraulic cylinder for tilting up/down an outboard motor body of an outboard motor and a power steering hydraulic cylinder swinging the outboard motor body of the outboard motor has been disclosed in JP-A-6-127475.
The cylinder device having a configuration which uses a normal/reverse rotation type hydraulic power source is available in the related art. By use of the normal/reverse rotation type hydraulic power source, there is a merit that complication of an oil-hydraulic circuit can be suppressed.
On the other hand, when the normal/reverse rotation type hydraulic power source is used, it is difficult to replace hydraulic oil in the oil-hydraulic circuit with oil in a tank. Accordingly, there is a defect that foreign matters are apt to stay in the hydraulic oil. This may cause a problem that the hydraulic oil deteriorates or an operating characteristic of the hydraulic oil changes.
An object of the present disclosure is to materialize a steering device etc. which can suitably replace hydraulic oil in an oil-hydraulic circuit with oil in a tank in a configuration using a normal/reverse rotation type hydraulic power source.
According to an aspect of the present disclosure, there is provided a steering device including: a cylinder; a normal/reverse rotation type hydraulic power source that is provided with a first discharge port and a second discharge port; an oil storage tank; a first oil passage that connects a first chamber of the cylinder with the first discharge port of the hydraulic power source; a second oil passage that connects a second chamber of the cylinder with the second discharge port of the hydraulic power source; an oil passage group that includes an oil passage or a plurality of oil passages connecting at least one of the first oil passage and the second oil passage with the oil storage tank; and a changeover valve group that includes a changeover valve or a plurality of changeover valves provided on the oil passage or the plurality of oil passages respectively included in the oil passage group, and that performs changeover between a state in which hydraulic oil recovered from the cylinder flows back to the oil storage tank and a state in which hydraulic oil supplied from the hydraulic power source to the cylinder does not flow back to the oil storage tank, in accordance with a state of hydraulic oil supplied by the hydraulic power source.
A steering device 1 according to Embodiment 1 will be described with reference to
For example, the steering device according to the present embodiment is a watercraft steering device 1 (which will be hereinafter referred to “steering device 1” simply) used in order to swing an outboard motor left and right. As shown in
The steering device 1 swings the outboard motor 300 left and right so that the steering device 1 can control a travelling direction of the hull 200. More specifically, the outboard motor 300 is attached to be connected to a piston 13c of a cylinder 13 of the steering device 1 which will be described later. Due to the piston 13c moving left and right, the outboard motor 300 is swung left and right accordingly.
As another example, the steering device 1 according to the present embodiment may be used in a configuration in which a rotary shaft of the propeller is provided fixedly to the hull and a rudder is provided at the rear of the propeller in the travelling direction thereof.
Successively, an oil-hydraulic circuit of the steering device 1 will be described with reference to
The hydraulic power source 14 driven by the motor 20 is a normal/reverse rotation type hydraulic power source provided with a first discharge port 14a and a second discharge port 14b. The hydraulic power source 14 performs any of a “normal rotation” operation, a “reverse rotation” operation and a “suspension” operation in accordance with control performed by a user. Hydraulic oil is stored in the oil storage tank 18.
The changeover valve 11 is provided on the oil passage C5. The changeover valve 11 is a valve which changes over an open state and a closed state of the oil passage C5 in accordance with a state of hydraulic oil supplied by the hydraulic power source 14. A specific configuration of the changeover valve 11 will be described later.
The check valve 12 is provided on the oil passage C1. The check valve 12 is a valve for controlling an open state and a closed state of the oil passage C1 in accordance with oil pressure of the hydraulic oil supplied by the hydraulic power source 14. A specific configuration of the check valve 12 will be described later.
The cylinder 13 is partitioned into a first chamber 13a and a second chamber 13b by the piston 13c.
The hydraulic power source 14 has the first discharge port 14a connected to the first chamber 13a through the oil passage C1 and the oil passage C3, and the second discharge port 14b connected to the second chamber 13b through the oil passage C2 and the oil passage C4.
The main valve 19 is provided with a spool 19a, a first check valve 19b, and a second check valve 19c. The main valve 19 is partitioned into a first shaft chamber 19d on the first check valve 19b side and a second shaft chamber 19e on the second check valve 19c side by the spool 19a.
The oil passage C1 connects the first discharge port 14a with the first shaft chamber 19d, and connects the first discharge port 14a with the check valve 15a. The oil passage C2 connects the second discharge port 14b with the second shaft chamber 19e, and connects the second discharge port 14b with the check valve 15b.
The first check valve 19b is connected to the first chamber 13a through the oil passage C3. On the other hand, the second check valve 19c is connected to the second chamber 13b through the oil passage C4.
Incidentally, the oil passage C1 and the oil passage C3 connecting the first discharge port 14a with the first chamber 13a through the main valve 19 may be generically referred to as first oil passage. In addition, the oil passage C2 and the oil passage C4 connecting the second discharge port 14b with the second chamber 13b through the main valve 19 may be generically referred to as second oil passage.
The changeover valve 11 is connected to the oil passage C5 connecting the oil passage C1 with the oil storage tank 18. The oil passage C6 connects the oil passage C1 between the check valve 12 and the first discharge port 14a with the changeover valve 11. The oil passage C5 may be hereinafter referred to as third oil passage, and the oil passage C6 may be hereinafter referred to as fourth oil passage.
Incidentally, the configuration in which the oil passage C1 and the oil storage tank 18 are connected with each other by the oil passage C5 has been described so far. However, the present disclosure is not limited thereto. For example, the configuration may be provided with an oil passage group C including an oil passage or a plurality of oil passages connecting at least one of the oil passage C1 and the oil passage C2 with the oil storage tank 18, and a changeover valve group V including a changeover valve or a plurality of changeover valves provided on the oil passage or the plurality of oil passages respectively included in the oil passage group C.
The manual valve 16, the check valve 17a and the check valve 17b are connected to the oil passage C7 which connects the oil passage C3 with the oil passage C4. The oil passage C8 connects the check valve 15a and the check valve 15b with the oil storage tank 18.
When the hydraulic power source 14 still tends to recover hydraulic oil even in a state in which the piston 13c has completely slid to the first chamber 13a side, the check valve 15a supplies hydraulic oil from the oil storage tank 18 to the hydraulic power source 14.
When the hydraulic power source 14 still tends to recover hydraulic oil even in a state in which the piston 13c has completely slid to the second chamber 13b side, the check valve 15b supplies hydraulic oil from the oil storage tank 18 to the hydraulic power source 14.
The manual valve 16 can be open/closed manually. Due to the manual valve 16 which is changed to an open state during maintenance etc. of the steering device 1, hydraulic oil is returned from the first chamber 13a to the second chamber 13b.
In the case where oil pressure on the cylinder 13 increases suddenly when hydraulic oil is supplied to the oil-hydraulic circuit so that the piston 13c slides from the first chamber 13a side toward the second chamber 13b side, the check valve 17a changes itself to an open state. Thus, a load of the oil pressure on the cylinder 13 can be suppressed.
In the case where the oil pressure on the cylinder 13 increases suddenly when the hydraulic oil is supplied to the oil-hydraulic circuit so that the piston 13c slides from the second chamber 13b side toward the first chamber 13a side, the check valve 17b changes itself to an open state. Thus, the load of the oil pressure on the cylinder 13 can be suppressed.
(Changeover Valve 11)
Successively, an example of the configuration of the changeover valve 11 will be described with reference to
When hydraulic oil is supplied from the first discharge port 14a and internal pressure of the oil passage C6 becomes not lower than second pressure, the changeover valve 11 shuts the oil passage C5. More specifically, due to the internal pressure of the oil passage C6 which becomes not lower than the second pressure, the plunger 11a slides toward a side where the sealing member 11b is provided. Thus, an opening portion of the oil passage C5 against which the sealing member 11b is pressed is closed by the sealing member 11b so that the oil passage C5 is shut.
When the hydraulic oil is supplied from the first discharge port 14a and the internal pressure of the oil passage C6 becomes lower than the second pressure, the changeover valve 11 opens the oil passage C5. More specifically, when the internal pressure of the oil passage C6 becomes lower than the second pressure, the plunger 11a is pressed by the spring 11c so that the plunger 11a moves toward the oil passage C6 side. Thus, since the sealing member 11b cannot be pressed against the opening portion of the oil passage C5 anymore, the oil passage C5 is opened.
Incidentally, also in the case where hydraulic oil is supplied from the second discharge port 14b, the internal pressure of the oil passage C6 becomes lower than the second pressure. Therefore, the changeover valve 11 opens the oil passage C5 also in the case where the hydraulic oil is supplied from the second discharge port 14b.
Thus, the changeover valve 11 performs changeover between a state in which hydraulic oil recovered from the cylinder 13 flows back to the oil storage tank 18, and a state in which hydraulic oil supplied from the hydraulic power source 14 to the cylinder 13 does not flow back to the oil storage tank 18, in accordance with the state of the hydraulic oil supplied by the hydraulic power source 14.
(Check Valve 12)
When hydraulic oil is supplied from the first discharge port 14a and the supplied hydraulic oil becomes not lower than first pressure higher than the aforementioned second pressure, the check valve 12 turns to an open state. More specifically, when internal pressure of the oil passage C1 between the check valve 12 and the first discharge port 14a becomes not lower than the first pressure, the check valve 12 turns to the open state to open the oil passage C1.
When the hydraulic oil is supplied from the first discharge port 14a and the internal pressure of the oil passage C1 between the check valve 12 and the first discharge port 14a becomes lower than the first pressure, the check valve 12 turns to a closed state to shut the oil passage C1. Incidentally, also when the hydraulic oil is supplied from the second discharge port 14b, the internal pressure of the oil passage C1 between the check valve 12 and the first discharge port 14a becomes lower than the first pressure. Therefore, also when hydraulic oil is supplied from the second discharge port 14b, the check valve 12 turns to the closed state to shut the oil passage C1.
(Operation Example of Steering Device 1)
Successively, an operation example of the steering device 1 having the aforementioned configuration will be described below.
(Normal Rotation Operation of Hydraulic Power Source 14)
When the hydraulic power source 14 rotates in a normal direction, hydraulic oil is supplied from the second discharge port 14b to the second shaft chamber 19e through the oil passage C2. Thus, the second check valve 19c is opened, and the spool 19a moves toward the first check valve 19b to thereby open the first check valve 19b.
When the second check valve 19c is opened, the hydraulic oil supplied to the second shaft chamber 19e is supplied to the second chamber 13b through the oil passage C4. Due to the hydraulic oil supplied to the second chamber 13b, the piston 13c slides from the second chamber 13b side toward the first chamber 13a side.
When the piston 13c slides in this manner, the hydraulic oil is supplied from the first chamber 13a to the first shaft chamber 19d through the oil passage C3 and the first check valve 19b. Here, when the hydraulic oil is supplied from the second discharge port 14b, the changeover valve 11 turns to an open state to open the oil passage C5, as described above. In addition, when the hydraulic oil is supplied from the second discharge port 14b, the check valve 12 turns to a closed state to shut the oil passage C1. Therefore, the hydraulic oil supplied to the first shaft chamber 19d is supplied to the oil storage tank 18 through the oil passage C5. Then, the hydraulic oil stored in the oil storage tank 18 is supplied to the hydraulic power source 14 through the oil passage C8.
Thus, in the steering device 1 according to the present embodiment, when the hydraulic power source 14 is rotated in the normal direction, the hydraulic oil in the first chamber 13a of the cylinder 13 can be supplied to the oil storage tank 18, and the hydraulic oil in the oil storage tank 18 can be supplied to the second chamber 13b of the cylinder 13. Thus, the hydraulic oil in the cylinder 13 can be replaced with the hydraulic oil in the oil storage tank 18.
(Reverse Rotation Operation of Hydraulic Power Source 14)
When the hydraulic power source 14 rotates in a reverse direction, hydraulic oil is supplied from the first discharge port 14a to the changeover valve 11 through the oil passage C6, and supplied to the check valve 12 through the oil passage C1. Since the oil passage C6 and the oil passage C1 have been shut by the changeover valve 11 and the check valve 12 respectively, the internal pressure of the oil passage C6 and the internal pressure of the oil passage C1 increase to the second pressure and then increase to the first pressure.
When the internal pressure of the oil passage C6 becomes not lower than the second pressure, the changeover valve 11 turns to a closed state to shut the oil passage C5. In addition, when the internal pressure of the oil passage C1 becomes not lower than the first pressure, the check valve 12 turns to an open state to open the oil passage C1.
When the oil passage C1 is opened, the hydraulic oil supplied to the check valve 12 is supplied to the first shaft chamber 19d through the oil passage C1. Thus, the first check valve 19b is opened, and the spool 19a moves toward the second check valve 19c side to open the second check valve 19c.
When the first check valve 19b is opened, the hydraulic oil supplied to the first shaft chamber 19d is supplied to the first chamber 13a through the oil passage C3. Due to the hydraulic oil supplied to the first chamber 13a, the piston 13c slides from the first chamber 13a side toward the second chamber 13b side.
When the piston 13c slides in this manner, the hydraulic oil is supplied from the second chamber 13b to the second shaft chamber 19e through the oil passage C4 and the second check valve 19c, and the hydraulic oil supplied to the second shaft chamber 19e is supplied to the hydraulic power source 14.
Thus, in the steering device 1, the hydraulic power source 14 can be controlled to perform the normal rotation operation to thereby replace the hydraulic oil in the cylinder 13 with the hydraulic oil in the oil storage tank 18. Thus, it is possible to (1) suppress an increase of temperature of the hydraulic oil, (2) suppress deterioration of the hydraulic oil, and (3) remove foreign matters in the oil-hydraulic circuit. Accordingly, it is possible to provide the steering device 1 whose operating characteristic hardly changes.
A steering device 2 according to Embodiment 2 will be described with reference to
As shown in
Successively, an example of the configuration of the changeover valve 21 will be described with reference to
When hydraulic oil is supplied from the second discharge port 14b and internal pressure of the oil passage C10 becomes not lower than fourth pressure, the changeover valve 21 shuts the oil passage C9. More specifically, due to the internal pressure of the oil passage C10 which becomes not lower than the fourth pressure, the plunger 21a slides toward a side where the sealing member 21b is provided. Thus, an opening portion of the oil passage C9 against which the sealing member 21b is pressed is closed by the sealing member 21b to thereby shut the oil passage C9.
When the hydraulic oil is supplied from the second discharge port 14b and the internal pressure of the oil passage C10 becomes lower than the fourth pressure, the changeover valve 21 opens the oil passage C9. More specifically, when the internal pressure of the oil passage C10 becomes lower than the fourth pressure, the plunger 21a is pressed by the spring 21c so that the plunger 21a moves toward the oil passage C10 side. Thus, since the sealing member 21b cannot be pressed against the opening portion of the oil passage C9 anymore, the oil passage C9 is opened.
Incidentally, also when hydraulic oil is supplied from a first discharge port 14a, the internal pressure of the oil passage C10 becomes lower than the fourth pressure. Therefore, the changeover valve 21 opens the oil passage C9 also when the hydraulic oil is supplied from the first discharge port 14a.
The check valve 22 has a configuration corresponding to the check valve 12, i.e. a configuration serving for controlling an opened state and a shut state of the oil passage C2 in accordance with oil pressure of hydraulic oil supplied from a hydraulic power source 14. When the hydraulic oil is supplied from the second discharge port 14b and the supplied hydraulic oil becomes not lower than third pressure higher than the aforementioned fourth pressure, the check valve 22 turns to an open state. More specifically, when internal pressure of the oil passage C2 between the check valve 22 and the second discharge port 14b becomes not lower than the third pressure, the check valve 22 turns to the open state to open the oil passage C2.
In addition, when the hydraulic oil is supplied from the second discharge port 14b and the internal pressure of the oil passage C2 between the check valve 22 and the second discharge port 14b becomes lower than the third pressure, the check valve 22 turns to a closed state to shut the oil passage C2. Incidentally, also when hydraulic oil is supplied from the first discharge port 14a, the check valve 22 turns to the closed state to shut the oil passage C2.
(Operation Example of Steering Device 2)
An operation example of the steering device 2 having the aforementioned configuration will be described below.
(Normal Rotation Operation of Hydraulic Power Source 14)
When the hydraulic power source 14 rotates in a normal direction, hydraulic oil is supplied from the second discharge port 14b to the changeover valve 21 through the oil passage C10 and supplied to the check valve 22 through the oil passage C2. Since the oil passage C10 and the oil passage C2 are shut by the changeover valve 21 and the check valve 22 respectively, the internal pressure of the oil passage C10 and the internal pressure of the oil passage C2 increase to the fourth pressure, and then increase to the third pressure.
When the internal pressure of the oil passage C10 becomes not lower than the fourth pressure, the changeover valve 21 turns to a closed state to shut the oil passage C9. In addition, when the internal pressure of the oil passage C2 becomes not lower than the third pressure, the check valve 22 turns to an open state to open the oil passage C2.
When the oil passage C2 is opened, the hydraulic oil supplied to the check valve 22 is supplied to a second shaft chamber 19e through the oil passage C2.
The hydraulic oil supplied to the second shaft chamber 19e is supplied to a first shaft chamber 19d through an oil passage C4, a cylinder 13, and an oil passage C3 in a manner similar to or the same as the steering device 1 in Embodiment 1.
Here, when the hydraulic oil is supplied from the second discharge port 14b, a changeover valve 11 turns to an open state to open an oil passage C5, and a check valve 12 turns to a closed state to shut an oil passage C1, as described above. Therefore, the hydraulic oil supplied to the first shaft chamber 19d is supplied to the oil storage tank 18 through the oil passage C5. Next, the hydraulic oil stored in the oil storage tank 18 is supplied to the hydraulic power source 14 through an oil passage C8.
Thus, in the steering device 2, when the hydraulic power source 14 is rotated in the normal direction, hydraulic oil in a first chamber 13a of the cylinder 13 can be supplied to the oil storage tank 18, and the hydraulic oil in the oil storage tank 18 can be supplied to a second chamber 13b of the cylinder 13. Thus, the hydraulic oil in the cylinder 13 can be replaced with the hydraulic oil in the oil storage tank 18.
(Reverse Rotation Operation of Hydraulic Power Source 14)
When the hydraulic power source 14 rotates in a reverse direction, hydraulic oil is supplied from the first discharge port 14a to the changeover valve 11 through an oil passage C6, and supplied to the check valve 12 through the oil passage C1.
When the hydraulic oil is supplied from the first discharge port 14a and internal pressure of the oil passage C6 becomes not lower than second pressure, the steering device 2 changes the changeover valve 11 to a closed state to shut the oil passage C5, in a manner similar to or the same as the steering device 1. In addition, when internal pressure of the oil passage C1 becomes not lower than first pressure, the steering device 2 changes the check valve 12 to an open state to open the oil passage C1.
In the steering device 2, the hydraulic oil supplied from the first discharge port 14a when the oil passage C1 is opened is supplied to the second shaft chamber 19e through the first shaft chamber 19d, the oil passage C3, the cylinder 13 and the oil passage C4, in a manner similar to or the same as that in the steering device 1.
Here, when the hydraulic oil is supplied from the first discharge port 14a, the changeover valve 21 turns to an open state to open the oil passage C9, and the check valve 22 turns to a closed state to shut the oil passage C2, as described above. Therefore, the hydraulic oil supplied to the second shaft chamber 19e is supplied to the oil storage tank 18 through the oil passage C9. Next, the hydraulic oil stored in the oil storage tank 18 is supplied to the hydraulic power source 14 through the oil passage C8.
Thus, when rotating the hydraulic power source 14 in the reverse direction, the steering device 2 can supply the hydraulic oil in the second chamber 13b of the cylinder 13 to the oil storage tank 18, and can supply the hydraulic oil in the oil storage tank 18 to the first chamber 13a of the cylinder 13. Thus, the hydraulic oil in the cylinder 13 can be replaced with the hydraulic oil in the oil storage tank 18.
Thus, in the steering device 2, the normal rotation operation and the reverse rotation operation of the hydraulic power source 14 are performed repeatedly so that the hydraulic oil in the cylinder 13 can be replaced with the hydraulic oil in the oil storage tank 18. Thus, it is possible to (1) suppress an increase of temperature of the hydraulic oil, (2) suppress deterioration of the hydraulic oil, and (3) remove foreign matters in the oil-hydraulic circuit. Accordingly, it is possible to provide the steering device 2 whose operating characteristic hardly changes.
A steering device 3 according to Embodiment 3 will be described with reference to
As shown in
Successively, an example of the configuration of the changeover valve 23 will be described with reference to
As shown in
When hydraulic oil is supplied from the second discharge port 14b and internal pressure of the oil passage C11 becomes not lower than fifth pressure, the changeover valve 23 opens an oil passage C5. More specifically, due to the internal pressure of the oil passage C11 which becomes not lower than the fifth pressure, the plunger 23a slides in a direction approaching the sealing member 23b to push the sealing member 23b. Thus, since the sealing member 23b cannot be pressed against an opening portion of the oil passage C5 anymore, the oil passage C5 is opened.
When the hydraulic oil is supplied from the second discharge port 14b and the internal pressure of the oil passage C11 becomes lower than the fifth pressure, the changeover valve 23 shuts the oil passage C5. More specifically, when the internal pressure of the oil passage C11 becomes lower than the fifth pressure, the sealing member 23b is pressed in a direction closing the opening portion of the oil passage C5 through the support member 23d supported by the spring 23c. Thus, the opening portion of the oil passage C5 against which the sealing member 23b is pressed is closed by the sealing member 23b so that the oil passage C5 is shut.
Incidentally, also when hydraulic oil is supplied from a first discharge port 14a, the internal pressure of the oil passage C11 becomes lower than the fifth pressure. Therefore, the changeover valve 23 shuts the oil passage C5 also when the hydraulic oil is supplied from the first discharge port 14a.
Incidentally, with provision of the O-ring 23e on the outer circumferential portion of the plunger 23a, the changeover valve 23 blocks movement of hydraulic oil between the oil passage C5 and the oil passage C11.
Thus, the changeover valve 23 is configured to perform changeover between a state in which hydraulic oil recovered from a cylinder 13 flows back to an oil storage tank 18 and a state in which hydraulic oil supplied from a hydraulic power source 14 to the cylinder 13 does not flow back to the oil storage tank 18, in accordance with the state of the hydraulic oil supplied by the hydraulic power source 14.
(Operation Example of Steering Device 3)
An operation example of the steering device 3 having the aforementioned configuration will be described below.
(Normal Rotation Operation of Hydraulic Power Source 14)
When the hydraulic power source 14 rotates in a normal direction, hydraulic oil is supplied from the second discharge port 14b to the second shaft chamber 19e through the oil passage C2, and hydraulic oil is supplied to the changeover valve 23 through the oil passage C11. Since the oil passage C11 is shut by the changeover valve 23, the internal pressure of the oil passage C11 increases to the fifth pressure.
When the internal pressure of the oil passage C11 becomes not lower than the fifth pressure, the changeover valve 23 turns to an open state to open the oil passage C5.
The hydraulic oil supplied to the second shaft chamber 19e is supplied to a first shaft chamber 19d through an oil passage C4, the cylinder 13, and an oil passage C3 in a manner similar to or the same as that in the aforementioned steering device 1.
Here, when the hydraulic oil is supplied from the second discharge port 14b and the internal pressure of the oil passage C11 becomes not lower than the fifth pressure, the changeover valve 23 turns to the open state to open the oil passage C5, and on the other hand, a check valve 12 turns to a closed state to shut an oil passage C1. Therefore, the hydraulic oil supplied to the first shaft chamber 19d is supplied to the oil storage tank 18 through the oil passage C5. Next, the hydraulic oil stored in the oil storage tank 18 is supplied to the hydraulic power source 14 through an oil passage C8.
Thus, in the steering device 3 according to the present embodiment, when the hydraulic power source 14 is rotated in the normal direction, hydraulic oil in a first chamber 13a of the cylinder 13 can be supplied to the oil storage tank 18, and the hydraulic oil in the oil storage tank 18 can be supplied to a second chamber 13b of the cylinder 13. Thus, the hydraulic oil in the cylinder 13 can be replaced with the hydraulic oil in the oil storage tank 18.
(Reverse Rotation Operation of Hydraulic Power Source 14)
When the hydraulic power source 14 rotates in a reverse direction, hydraulic oil is supplied from the first discharge port 14a to the check valve 12 through the oil passage C1. Since the oil passage C1 is shut by the check valve 12, internal pressure of the oil passage C1 increases to first pressure. When the internal pressure of the oil passage C1 becomes not lower than the first pressure, the check valve 12 turns to an open state to open the oil passage C1.
Here, when the hydraulic oil is supplied from the first discharge port 14a, the changeover valve 23 shuts the oil passage C5, as described above. Therefore, the hydraulic oil supplied from the first discharge port 14a to the check valve 12 is supplied to the first shaft chamber 19d through the oil passage C1.
The hydraulic oil supplied to the first shaft chamber 19d is supplied to the hydraulic power source 14 through the oil passage C3, the cylinder 13, the oil passage C4, the second shaft chamber 19e and the oil passage C2 in a manner similar to or the same as that in the aforementioned steering device 1.
Thus, according to the steering device 3, when the hydraulic power source 14 is operated to rotate in the normal direction, the hydraulic oil in the cylinder 13 can be replaced with the hydraulic oil in the oil storage tank 18. Thus, it is possible to (1) suppress an increase of temperature of the hydraulic oil, (2) suppress deterioration of the hydraulic oil, and (3) remove foreign matters in the oil-hydraulic circuit. Accordingly, it is possible to provide the steering device 3 whose operating characteristic hardly changes.
A steering device 4 according to Embodiment 4 will be described with reference to
As shown in
Successively, an example of the configuration of the changeover valve 24 will be described with reference to
When hydraulic oil is supplied from the first discharge port 14a and internal pressure of the oil passage C12 becomes not lower than sixth pressure, the changeover valve 24 opens the oil passage C9. More specifically, due to the internal pressure of the oil passage C12 which becomes not lower than the sixth pressure, the plunger 24a slides in a direction approaching the sealing member 24b to push the sealing member 24b. Thus, since the sealing member 24b cannot be pressed against an opening portion of the oil passage C9 anymore, the oil passage C9 is opened.
When hydraulic oil is supplied from the first discharge port 14a and the internal pressure of the oil passage C12 becomes lower than the sixth pressure, the changeover valve 24 shuts the oil passage C9. More specifically, when the internal pressure of the oil passage C12 becomes lower than the sixth pressure, the sealing member 24b is pressed in a direction closing the opening portion of the oil passage C9 through the support member 24d supported by the spring 24c. Thus, the opening portion of the oil passage C9 against which the sealing member 24b is pressed is closed by the sealing member 24b so that the oil passage C9 is shut.
Incidentally, also when the hydraulic oil is supplied from a second discharge port 14b, the internal pressure of the oil passage C12 becomes lower than the sixth pressure. Therefore, the changeover valve 24 shuts the oil passage C9 also when the hydraulic oil is supplied from the second discharge port 14b.
Here, the check valve 12 is configured so that first pressure is higher than the sixth pressure. In addition, the check valve 22 is configured so that third pressure is higher than fifth pressure.
(Operation Example of Steering Device 4)
An operation example of the steering device 4 having the aforementioned configuration will be described below.
(Normal Rotation Operation of Hydraulic Power Source 14)
When a hydraulic power source 14 rotates in a normal direction, hydraulic oil is supplied from the second discharge port 14b to the check valve 22 through an oil passage C2, and hydraulic oil is supplied to a changeover valve 23 through an oil passage C11. Since the oil passage C2 and the oil passage C11 are shut by the check valve 22 and the changeover valve 23 respectively, internal pressure of the oil passage C2 and internal pressure of the oil passage C11 increase to the fifth pressure, and then increase to the third pressure.
When the internal pressure of the oil passage C11 becomes not lower than the fifth pressure, the changeover valve 23 turns to an open state to open an oil passage C5. In addition, when the internal pressure of the oil passage C2 becomes not lower than the third pressure, the check valve 22 turns to an open state to open the oil passage C2.
In the steering device 4 according to the present embodiment, when the oil passage C2 is opened, the hydraulic oil supplied to the check valve 22 is supplied to a first shaft chamber 19d through the oil passage C2, a second shaft chamber 19e, an oil passage C4, a cylinder 13 and an oil passage C3, in a manner similar to or the same as that in the aforementioned steering device 2.
Here, when the hydraulic oil is supplied from the second discharge port 14b and internal pressure of the oil passage C1 becomes not lower than the fifth pressure, the changeover valve 23 turns to the open state to open the oil passage C5, and on the other hand, the check valve 12 turns to a closed state to shut the oil passage C1. Therefore, the hydraulic oil supplied to the first shaft chamber 19d is supplied to an oil storage tank 18 through the oil passage C5. Next, the hydraulic oil stored in the oil storage tank 18 is supplied to the hydraulic power source 14 through an oil passage C8.
Thus, in the steering device 4, when the hydraulic power source 14 is rotated in the normal direction, hydraulic oil in a first chamber 13a of the cylinder 13 can be supplied to the oil storage tank 18, and the hydraulic oil in the oil storage tank 18 can be supplied to a second chamber 13b of the cylinder 13. Thus, the hydraulic oil in the cylinder 13 can be replaced with the hydraulic oil in the oil storage tank 18.
(Reverse Rotation Operation of Hydraulic Power Source 14)
When the hydraulic power source 14 rotates in a reverse direction, hydraulic oil is supplied from the first discharge port 14a to the check valve 12 through the oil passage C1, and hydraulic oil is supplied to the changeover valve 24 through the oil passage C12. Since the oil passage C1 and the oil passage C12 are shut by the check valve 12 and the changeover valve 24 respectively, the internal pressure of the oil passage C1 and the internal pressure of the oil passage C12 increase to the sixth pressure, and then increase to the first pressure.
When the internal pressure of the oil passage C12 becomes not lower than the sixth pressure, the changeover valve 24 turns to an open state to open the oil passage C9. In addition, when the internal pressure of the oil passage C1 becomes not lower than the first pressure, the check valve 12 turns to an open state to open the oil passage C1.
In the steering device 4 according to the present embodiment, when the oil passage C1 is opened, the hydraulic oil supplied to the check valve 12 is supplied to the second shaft chamber 19e through the oil passage C1, the first shaft chamber 19d, the oil passage C3, the cylinder 13 and the oil passage C4, in a manner similar to or the same as that in the aforementioned steering device 2.
Here, when the hydraulic oil is supplied from the first discharge port 14a and the internal pressure of the oil passage C12 becomes not lower than the sixth pressure, the changeover valve 24 turns to the open state to open the oil passage C9 as described above. On the other hand, the check valve 22 turns to a closed state to shut the oil passage C2. Therefore, the hydraulic oil supplied to the second shaft chamber 19e is supplied to the oil storage tank 18 through the oil passage C9. Next, the hydraulic oil stored in the oil storage tank 18 is supplied to the hydraulic power source 14 through the oil passage C8.
Thus, in the steering device 4 according to the present embodiment, when the hydraulic power source 14 is rotated in the reverse direction, the hydraulic oil in the second chamber 13b of the cylinder 13 can be supplied to the oil storage tank 18, and the hydraulic oil in the oil storage tank 18 can be supplied to the first chamber 13a of the cylinder 13. Thus, the hydraulic oil in the cylinder 13 can be replaced with the hydraulic oil in the oil storage tank 18.
Thus, according to the steering device 4, the normal rotation operation and the reverse rotation operation of the hydraulic power source 14 are performed repeatedly so that the hydraulic oil in the cylinder 13 can be replaced with the hydraulic oil in the oil storage tank 18. Thus, it is possible to (1) suppress an increase of temperature of the hydraulic oil, (2) suppress deterioration of the hydraulic oil, and (3) remove foreign matters in the oil-hydraulic circuit. Accordingly, it is possible to provide the steering device 4 whose operating characteristic hardly changes.
According to an aspect of the present disclosure, it is possible to replace hydraulic oil in an oil-hydraulic circuit with oil in a tank in a configuration using a normal/reverse rotation type hydraulic power source.
The present invention is not limited to the aforementioned embodiments but may be changed variously within the scope of CLAIMS. Any embodiment obtained by suitably combining technical units disclosed in different embodiments respectively is also included in the technical scope of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-091620 | May 2019 | JP | national |
