Patent Grant
8505874
The present invention relates to an adjusting screw structure of an oil immersed solenoid used in an oil-pressure device, such as a valve device, used in a construction machinery or the like, and an oil immersed solenoid including the adjusting screw structure.
One example of such oil immersed solenoid is shown in
However, if air and air bubbles exist in the oil, such as the operating oil, in the space 6 of the oil immersed solenoid 1, this may cause an irregular change in acceleration of the movable core 4, and chattering of the movable core 4 may occur.
Here, in order to remove the air and the air bubbles in the space 6 of the solenoid 1, an adjusting screw 9 is provided to threadedly engage with a rear metal member 8 sealing a rear opening 7 of the solenoid 1 shown in
Moreover, even among the standardized oil immersed solenoids 1 shown in
Here, as shown in
With this, when a predetermined command electric signal is transmitted to the solenoid 1, the biasing force of the adjusting spring 10 can be adjusted by the adjusting screw 9 in advance or accordingly such that each of the predetermined pressure and flow rate is proportional to the command electric signal and falls within a predetermined allowable range.
Another example of the oil immersed solenoid 1 is disclosed in Japanese Laid-Open Patent Application Publication No. 2006-140417 (see PTL 1 for example).
In accordance with the conventional oil immersed solenoid 1 shown in
Moreover, since the adjusting screw 9 cannot be surely put back to the original adjustment position, an error occurs between the biasing force of the adjusting spring 10 readjusted by the adjusting screw 9 and the original biasing force.
Further, in a case where the adjusting screw 9 is detached from the rear metal member 8 to remove the air, the adjusting spring 10 remains in the solenoid 1. However, in a case where the oil is supplied to the solenoid 1 to cause the air in the solenoid 1 to flow out, the adjusting spring 10 may be pushed out through the screw hole 8a to the outside of the solenoid 1, and the adjusting spring 10 may be lost. Then, when the operator inserts the adjusting spring 10 through the screw hole 8a into the solenoid 1 after the removal of the air, the adjusting spring 10 may be sandwiched between the adjusting screw 9 and an inner surface of the screw hole 8a.
Moreover, for example, when checking the operations of the oil immersed solenoid 1 before shipment, a reasonable work procedure is to check complete removal of the air and the air bubbles in the solenoid 1 and then adjusting the biasing force of the adjusting spring 10 by the adjusting screw 9. However, since this work procedure cannot be changed, workability may deteriorate.
Further, after the adjusting screw 9 is loosened to remove the air in the oil immersed solenoid 1, the adjusting spring 10 needs to be adjusted. In addition, in a state where the oil immersed solenoid 1 is mounted on the oil-pressure device, such as the valve device, it is difficult to adjust the biasing force of the adjusting spring 10. In view of these, it is difficult to remove the air by loosening the adjusting screw 9 in a state where the oil immersed solenoid 1 is mounted on the oil-pressure device. Therefore, there is a need for the oil immersed solenoid capable of solving this problem.
The present invention was made to solve the above problem, and an object of the present invention is to provide an adjusting screw structure of an oil immersed solenoid, the adjusting screw structure being capable of removing the air in the solenoid without causing an error in biasing force of the adjusting spring adjusted by the adjusting screw and easily adjusting the biasing force of the adjusting spring and removing the air, and an oil immersed solenoid including the adjusting screw structure.
An adjusting screw structure of an oil immersed solenoid according to the present invention is an adjusting screw structure of an oil immersed solenoid in which: a movable core is provided in a space of a case so as to be movable in an axial direction; the movable core is biased by an adjusting spring in a direction in which the movable core is pulled by a fixed magnetic pole portion or in an opposite direction thereof; and an adjusting screw capable of adjusting biasing force of the adjusting spring is included, the adjusting screw structure including an air-bleeding plug configured to be detachably attached to and seal an opening end portion of the case, the opening end portion communicating with the space of the case, wherein the air-bleeding plug includes an internal screw portion with which the adjusting screw threadedly engages and a detachable mechanism configured to be able to attach the air-bleeding plug to the opening end portion of the case such that the air-bleeding plug is located at a predetermined attachment position in a movement direction of the adjusting screw.
In accordance with the adjusting screw structure of the oil immersed solenoid of the present invention, the biasing force of the adjusting spring can be adjusted by rotating the adjusting screw in a direction in which the adjusting screw is tightened or loosened. By adjusting the biasing force of the adjusting spring, it is possible to adjust the biasing force in a direction in which the movable core moves in a direction toward the fixed magnetic pole portion or in its opposite direction. With this, it is possible to adjust the oil pressure and flow rate of the operating oil or the like flowing in, for example, a valve device in which the oil immersed solenoid is used.
Then, by loosening the air-bleeding plug, the air and the air bubbles in the oil in the space of the case can be removed through the opening end portion of the case. Moreover, since the air-bleeding plug can be attached to the opening end portion of the case to be positioned at the predetermined attachment position in the movement direction of the adjusting screw, and a positional relation between the adjusting screw and the air-bleeding plug does not change even when the air-bleeding plug is attached to and detached from the opening end portion, the adjusting screw can be put back to the original position by attaching the air-bleeding plug again. Therefore, the error of the biasing force of the adjusting spring adjusted by the adjusting screw does not occur, and the readjustment by the adjusting screw becomes unnecessary.
In the adjusting screw structure of the oil immersed solenoid according to the present invention, the detachable mechanism may include: a detachable screw portion configured to attach the air-bleeding plug to the opening end portion of the case such that the air-bleeding plug threadedly engages with the opening end portion; an annular sealing portion configured to be attached to an annular groove formed on an outer peripheral surface of the air-bleeding plug; a sealing inclined surface configured to be formed in an annular shape on an inner peripheral surface of the opening end portion of the case, have an inner diameter increasing in size toward the opening, and tightly contact the annular sealing portion when the air-bleeding plug is attached at an attachment position of the opening end portion; and an air-bleeding hole configured to be formed on the air-bleeding plug and allow the space of the case and an outside of the oil immersed solenoid to communicate with each other when the air-bleeding plug is loosened.
In accordance with the detachable mechanism, the air-bleeding plug can be attached to the opening end portion of the case at the attachment position by the detachable screw portion so as to threadedly engage with the opening end portion. With the air-bleeding plug attached at the attachment position, the annular sealing portion attached to the outer peripheral surface of the air-bleeding plug tightly contacts the sealing inclined surface formed on the inner peripheral surface of the opening end portion of the case to seal the space of the case and prevent the oil in the case from leaking.
Then, when removing the air and the air bubbles in the oil in the space of the case, the air-bleeding plug is loosened. In this state, the air-bleeding hole formed on the air-bleeding plug can allow the space of the case and the outside of the oil immersed solenoid to communicate with each other, so that the air and the like in the case can be removed through the air-bleeding hole. The sealing inclined surface has an inner diameter increasing in size toward the opening. Therefore, by loosening the air-bleeding plug, a gap is formed between the sealing inclined surface and the annular sealing portion, and the air and the like in the case can be efficiently discharged through the gap to the outside.
Moreover, the air-bleeding plug may be loosened, and the air and the like in the case can be removed without detaching the air-bleeding plug from the opening end portion. Therefore, the adjusting spring in the case does not flow out through the opening end portion together with the oil, and there is no possibility of losing the adjusting spring. Then, when the operator tightens the air-bleeding plug to the opening end portion of the case after the removal of the air, the adjusting spring is not sandwiched between the adjusting screw and the inner surface of the opening end portion.
In the adjusting screw structure of the oil immersed solenoid according to the present invention, the detachable mechanism may further include a pressing inclined surface configured to be formed in an annular shape on the inner peripheral surface of the opening end portion of the case, have an inner diameter increasing in size toward the opening, be located on an opening side of the sealing inclined surface, and press the annular sealing portion into the annular groove when the air-bleeding plug threadedly engages with the opening end portion of the case to be tightened into the opening end portion.
In accordance with the detachable mechanism, when the air-bleeding plug is tightened to threadedly engage with the opening end portion of the case, the pressing inclined surface formed in an annular shape on the inner peripheral surface of the opening end portion of the case can press the annular sealing portion attached to the annular groove into the annular groove. Then, when the air-bleeding plug is further tightened, the annular sealing portion attached to the air-bleeding plug can tightly contact the sealing inclined surface formed on the inner peripheral surface of the opening end portion of the case to seal the space in the case. As above, the air-bleeding plug can be attached to the opening end portion of the case with the annular sealing portion not protruding from the annular groove, and the sealed state can be secured. Therefore, when the air-bleeding plug is tightened to be attached to the opening end portion of the case, the annular sealing portion is prevented from protruding from the annular groove and being sandwiched.
In the adjusting screw structure of the oil immersed solenoid according to the present invention, the detachable mechanism may further include a seal supporting surface configured to be formed in an annular shape on the inner peripheral surface of the opening end portion of the case, be located between the pressing inclined surface and the sealing inclined surface, and extend substantially in parallel with a center axis of the air-bleeding plug.
In accordance with the detachable mechanism, with the air-bleeding plug attached to the opening end portion of the case, the annular sealing portion in the annular groove can tightly contact the sealing inclined surface to seal the space in the case. Then, the seal supporting surface formed on the inner peripheral surface of the opening end portion of the case located on the opening side of the sealing inclined surface extends substantially in parallel with the center axis of the air-bleeding plug, and the length of the gap between the seal supporting surface and the outer peripheral surface of the air-bleeding plug becomes substantially constant at respective positions in a direction along the center axis of the air-bleeding plug. With this, the annular sealing portion can be prevented from being pushed out from the annular groove to the outside by the pressure of the oil in the case.
In the adjusting screw structure of the oil immersed solenoid according to the present invention, the adjusting spring may be a coil spring, a base end portion of the adjusting spring may fit and be attached to a first spring seat formed at a tip end portion of the adjusting screw, a tip end portion of the adjusting spring may fit and be attached to a second spring seat, and each of the first and second spring seats may include a convex stop portion configured to stop a movement in a direction in which the base end portion or tip end portion of the adjusting spring is detached therefrom.
In a case where each of the first and second spring seats includes the convex stop portion configured to stop the movement in a direction in which the base end portion or tip end portion of the adjusting spring is detached therefrom, the adjusting screw, the adjusting spring, and the second spring seat can be comparatively strongly coupled to one another by the convex stop portion. Even when the air-bleeding plug is detached from the opening end portion of the case in a case where the adjusting screw, the adjusting spring, and the second spring seat are comparatively strongly coupled to one another as above, the adjusting screw, the adjusting spring, and the second spring seat are not disassembled and can be prevented from being lost. Then, the adjusting spring is prevented from being sandwiched between the adjusting screw and the inner surface of the opening end portion when the air-bleeding plug is tightened to be attached to the opening end portion of the case after the removal of the air by the operator.
The oil immersed solenoid according to the present invention includes the adjusting screw structure of the present invention.
In accordance with the oil immersed solenoid of the present invention, the adjusting screw structure of the oil immersed solenoid of the present invention is included. Since the oil immersed solenoid of the present invention operates in the same manner as above, an explanation thereof is omitted.
In accordance with the adjusting screw structure of the oil immersed solenoid and the oil immersed solenoid of the present invention, the air-bleeding plug can be attached to the opening end portion of the case at a predetermined attachment position in the movement direction of the adjusting screw. Therefore, the air-bleeding plug can be loosened to remove the air in the solenoid without causing the error of the biasing force of the adjusting spring adjusted by the adjusting screw. To be specific, the loosened air-bleeding plug can be put back to the original position when attached to the opening end portion of the case.
With this, the adjustment of the biasing force of the adjusting spring by the adjusting screw and the removal of the air in the solenoid can be easily carried out in a suitable order in actual operations.
Moreover, it is difficult to adjust the biasing force of the adjusting spring in a state where the oil immersed solenoid is mounted on the oil-pressure device, such as the valve device. However, in accordance with the oil immersed solenoid of the present invention, since the error of the biasing force of the adjusting spring does not occur even after the removal of the air, it is unnecessary to adjust the biasing force of the adjusting spring. Therefore, with the oil immersed solenoid mounted on the oil-pressure device, the air can be easily removed by loosening the air-bleeding plug.
Hereinafter, an embodiment of each of an adjusting screw structure 15 of an oil immersed solenoid according to the present invention and the oil immersed solenoid including the adjusting screw structure 15 will be explained in reference to
The oil immersed solenoid 11 shown in
The exciting coil 12 shown in
A controller (not shown) freely adjusts the magnitude of the command electric signal within a predetermined range and transmits the command electric signal to the exciting coil 12. With this, the fixed magnetic pole portion 13 can generate pulling force (magnetic pole) corresponding to the magnitude of the command electric signal.
The magnetic pole is generated at the fixed magnetic pole portion 13 by the exciting coil 12, and the fixed magnetic pole portion 13 can pull the movable core 14 by the magnetic pole (pulling force in a left direction in
As shown in
As shown in
To be specific, the movable core 14 receives biasing force in the left direction in
A tip end portion of an outer peripheral surface of the second guide 20 is positioned on an inner side of a rear end portion of the first guide 19, and a substantially center portion of the outer peripheral surface of the second guide 20 is positioned on an inner side of a rear end portion of the exciting coil 12. Then, a rear end portion of the outer peripheral surface of the second guide 20 is positioned on an inner side of a rear end portion of the main body case 17. The second guide 20 is made of a magnetic metal.
Moreover, as shown in
Further, as shown in
As shown in
Moreover, as shown in
As shown in
As above, the pressing force of the first rod 21 with respect to the spool is adjusted in order that the oil pressure and flow rate of the operating oil flowing in the valve device are adjusted to become a predetermined oil pressure and flow rate corresponding to the command electric signal when the command electric signal is transmitted to the exciting coil 12.
As shown in
Moreover, the first space 22 shown in
As shown in
Then, as shown in partially enlarged cross-sectional views of
As shown in
Moreover, reference sign 39 shown in
Next, a detachable mechanism 40 configured to detachably attach the air-bleeding plug 32 to the opening end portion 30 of the rear case 25 will be explained in reference to
As shown in
As shown in
Moreover, as shown in
Further, as shown in
As shown in
To be specific, a small-diameter edge portion of the pressing inclined surface 48 is substantially the same in diameter as a large-diameter edge portion of the sealing inclined surface 46. The seal supporting surface 47 is formed between the sealing inclined surface 46 and the pressing inclined surface 48 and is substantially the same in diameter as the large-diameter edge portion of the sealing inclined surface 46. The seal supporting surface 47 is formed to have a short cylindrical shape extending substantially in parallel with a center axis of the air-bleeding plug 32. Moreover, each of the sealing inclined surface 46 and the pressing inclined surface 48 is inclined at about 15° (for example, 10° to 20°) to the center axis of the air-bleeding plug 32.
As shown in
As shown in
To be specific, when the air-bleeding plug 32 is tightened into the opening end portion 30 of the rear case 25, the annular sealing portion 42 is prevented from protruding from the annular groove 43 and being sandwiched between the rear end portion of the rear case 25 and the flange portion 32a.
Next, the operations of the oil immersed solenoid 11 and adjusting screw structure 15 configured as above and shown in
When the movable core 14 is pulled, the first rod 21 provided at the movable core 14 presses the spool of the valve device (not shown) in the left direction in
Even among the standardized oil immersed solenoids 11 shown in
Here, the operator can adjust the biasing force of the adjusting spring 26 by rotating the adjusting screw 27 of
Moreover, if the air and the air bubbles exist in the oil, such as operating oil, in the first space 22 of the oil immersed solenoid 11 shown in
Here, in order to remove the air and the air bubbles in the first space 22 of solenoid 11, the operator loosens the air-bleeding plug 32 as shown in
When removing the air and the like in the first space 22, for example, the oil, such as the operating oil, can be supplied through the tip end portion 11a of the solenoid 11 to cause the air and the like in the first space 22 to flow out through the opening end portion 30 of the rear case 25.
Moreover, as shown in
Therefore, even if the air is removed by loosening the air-bleeding plug 32, the error of the biasing force of the adjusting spring 26 adjusted by the adjusting screw 27 does not occur, so that it is unnecessary to readjust the adjusting screw 27.
Therefore, the adjustment of the biasing force of the adjusting spring 26 by the adjusting screw 27 and the removal of the air in the solenoid 11 can be easily carried out in a suitable order in actual operations.
Moreover, it is difficult to adjust the biasing force of the adjusting spring 26 in a state where the oil immersed solenoid 11 is mounted on the oil-pressure device, such as the valve device. However, in the oil immersed solenoid 11 of the present embodiment, the error of the biasing force of the adjusting spring 26 does not occur even if the air is removed. Therefore, it is unnecessary to adjust the biasing force of the adjusting spring 26. On this account, in accordance with the oil immersed solenoid 11, the removal of the air can be easily carried out by loosening the air-bleeding plug 32 in a state where the oil immersed solenoid 11 is mounted on the oil-pressure device.
Further, as shown in
As shown in
Moreover, when removing the air in the first and second spaces 22 and 28, the air-bleeding plug 32 may be loosened, and it is unnecessary to detach the air-bleeding plug 32 from the opening end portion 30. Therefore, the adjusting spring 26 and the second spring seat 35 in the rear case 25 do not flow out through the opening end portion 30 together with the oil and there is no possibility of losing the adjusting spring 26 and the second spring seat 35. Then, the adjusting spring 26 is prevented from being sandwiched between the adjusting screw 27 and the inner surface of the opening end portion 30 when the air-bleeding plug 32 is tightened to the opening end portion 30 of the case after the removal of the air by the operator.
Further, in accordance with the detachable mechanism 40, as shown in
Then, as shown in
In accordance with this configuration, the length of the gap between the seal supporting surface 47 and the outer peripheral surface portion 49 of the plug main body 41 becomes substantially constant at respective positions in a direction along the center axis of the air-bleeding plug 32. Therefore, it is possible to prevent the annular sealing portion 42 from being pushed out from the annular groove 43 to the outside by the oil pressure in the second space 28 of the rear case 25.
Moreover, as shown in
Further, as shown in
In the above embodiment, as shown in
Then, in the above embodiment, as shown in
| Number | Date | Country | Kind |
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| 2008-233896 | Sep 2008 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
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| PCT/JP2009/004110 | 8/26/2009 | WO | 00 | 3/23/2011 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2010/029695 | 3/18/2010 | WO | A |
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