JP2014163245A - Oil discharge mechanism of oil filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil discharge mechanism of an oil filter, which can be embodied at low cost by making no change to a conventional oil passage and improving an existing part in the oil passage, which forms a hydraulic circuit.SOLUTION: An oil discharging mechanism of an oil filter comprises a relief valve 1A having: a valve housing hole 104c communicating with oil passages 104a, 104b one side of which is closed by a closing member 4A and the other side of which leads to the oil filter; a valve piston 2A slidably housed in the valve housing hole 104c; a coil spring 3 interposed between the closing member and the valve piston 2A in the valve housing hole 104c ; and a drain port 109a formed in the valve housing hole 104c, opened and closed by the valve piston 2A, a traction rod 5A which extends through the closing member 4A and can tractionally operate the valve piston 2A from the outside of the relief valve 1A against spring force of the coil spring 3, and holding means 12 which can hold the valve piston 2A at a drain position by holding the traction rod 5A at a predetermined position against the spring force of the coil spring 3.

Description

  The present invention relates to an oil discharge mechanism for an oil filter, and more particularly to an oil discharge mechanism for an oil filter provided in a hydraulic circuit of an industrial vehicle, a construction vehicle, or the like.

  FIG. 14 shows a hydraulic circuit of a conventional forklift. The oil is sucked from the oil tank 100 via the strainer 101 by the pump 102 and discharged from the pump 102 to drive the torque converter 103, and the oil that has passed through the torque converter 103 passes through the oil passage 104 a and the oil filter 105. After passing through the cooler 106 and used as lubricating oil for the clutch 107 and the like, it is returned to the oil tank 100 again.

  As shown in FIG. 14, an oil filter 105 is connected to a hydraulic circuit of an industrial vehicle such as a forklift to filter the oil discharged by the pump 102. In general, relief valves (1X, 1Y, etc.) are provided to protect the lubricating oil circuit of the hydraulic circuit.

  The relief valve 1X is disposed at a position lower than the oil filter 105 through the oil passage 104b. As shown in FIGS. 15 and 16, the relief valve 1X communicates with a case 120 such as a transmission case and a torque converter case, or an oil block fixed to these casings, and communicates with an oil passage 104b leading to the oil filter 105. The formed valve accommodating hole 104c, a plug screw as a closing member 4X for closing the opening of the valve accommodating hole 104c, the valve piston 2X slidably accommodated in the valve accommodating hole 104c, and closed in the valve accommodating hole 104c The coil spring 3 is interposed between the member 4X and the valve piston 2X and presses and biases the valve piston 2X, and the drain port 109a is formed in the valve accommodating hole 104c and is opened and closed by the valve piston 2X. A stopper pin 108 capable of contacting the pressure receiving surface 2X1 of the valve piston 2X is fixed in the valve housing hole 104c.

  When the hydraulic pressure of the pressure receiving surface 2X1 of the valve piston 2X is smaller than the set pressure, the relief valve 1X closes the drain port 109a while the valve piston 2X is pressed against the stopper pin 108 by the coil spring 3, and the hydraulic pressure of the pressure receiving surface 2X1 is set. When the pressure becomes larger than the pressure, the valve piston 2X is pushed to the left as shown in FIG. 16 against the spring force of the coil spring 3, and the valve piston 2X moves to the drain position to open the drain port 109a. The portion is discharged from the drain port 109a through the drain oil passage 109 to the oil tank 100, and an excessive pressure rise is prevented. 15 and 16, oil leaking from the pressure receiving surface 2X1 side of the valve piston 2X1 to the coil spring 3 side of the valve housing hole 104c through the sliding surface of the valve piston 2X is opened in the valve housing hole 104c. Is discharged from another drain oil passage 110 to the oil tank 100.

  17 and 18 show the internal structure of the forklift. As shown, the oil filter 105 includes an oil cooler line hose 111 (FIG. 17), a transmission case 112 (FIG. 18), or a torque converter case. The oil remaining in the hose 111 and the oil filter 105 flows out when the filter element built in the oil filter 105 is replaced.

  When the oil filter 105 is connected to the hose 111 as shown in FIG. 17, oil leakage can be prevented by holding the hose end upward when the filter element is removed (see the two-dot chain line in FIG. 17). ). However, when the oil filter 105 is directly attached to the transmission case 112 as shown in FIG. 18 or directly attached to the torque converter case 113 (not shown), the installation space is limited. However, it is not possible to prevent oil leakage by a technique as in the case where the oil filter 105 is attached to the hose 111 as in the example of FIG.

  Therefore, in order to prevent the oil from overflowing or spilling out from the oil filter when the filter element of the oil filter is replaced, for example, the oil flows from the inflow path to the oil filter to the branch path that branches to the drain port. There has been proposed a drain structure of a fluid filter provided with a flow path switching member that enables passage from the fluid filter to the drain port by switching the path (Patent Document 1, etc.).

JP 2008-267322 A

  However, the conventional technology as described in Patent Document 1 requires a significant design change from existing ones, such as providing a drain oil path separately, and may cause a significant increase in cost.

  It is an object of the present invention to provide an oil discharge mechanism for an oil filter that can be realized at low cost by modifying existing parts in an oil passage constituting a hydraulic circuit without changing the conventional oil passage. Main purpose.

  In order to achieve the above object, an oil discharge mechanism for an oil filter according to the present invention includes a valve housing hole that is closed on one side by a closing member and communicated with an oil passage that communicates with the oil filter on the other side, and slides into the valve housing hole. A valve piston accommodated movably, a coil spring interposed between the closing member in the valve accommodation hole and the valve piston, and a drain port formed in the valve accommodation hole and opened and closed by the valve piston A relief valve that extends through the closure member, a traction rod that can pull the valve piston against the spring force of the coil spring from the outside of the closure member, and a resistance against the spring force of the coil spring And holding means capable of holding the valve piston in the drain position by holding the traction rod in a predetermined position.

  It is preferable that a concave portion is formed in the valve piston, and a tip portion of the traction rod is accommodated in the concave portion of the valve piston so as not to be removable while allowing relative movement of the valve piston.

  Furthermore, it is preferable that the tip end portion of the traction rod is urged to the back side of the recess by an auxiliary spring having a spring force smaller than that of the coil spring.

  Alternatively, a through hole is formed in the valve piston, the traction rod penetrates the through hole of the valve piston, and a locking portion for locking to the pressure receiving surface of the valve piston is provided at the tip of the traction rod. May be.

  Preferably, the holding means includes a locking pin that locks the traction rod and the closing member.

  According to the present invention, the relief valve can be forcibly held at the drain position by an external operation by adding an improvement to the relief valve normally provided for circuit protection of the hydraulic circuit. By discharging the oil passage from the Lilly valve to the oil filter to the oil tank before replacing the filter element, it is possible to provide an oil discharge mechanism for the oil filter at a low cost without changing the conventional oil passage. .

It is a vertical side view which shows 1st Embodiment of the oil discharge mechanism of the oil filter which concerns on this invention. It is a vertical side view which shows the modification of FIG. It is a vertical side view which shows 2nd Embodiment of the oil discharge mechanism of the oil filter which concerns on this invention. It is a vertical side view which shows 3rd Embodiment of the oil discharge mechanism of the oil filter which concerns on this invention. It is a longitudinal front view which expands and shows the principal part of the said 3rd Embodiment. It is a longitudinal cross-sectional view which shows 4th Embodiment of the oil discharge mechanism of the oil filter which concerns on this invention. FIG. 10 is a longitudinal sectional view showing an oil discharge mechanism of an oil filter according to a fifth embodiment of the present invention, viewed from the VI-VI view of FIG. FIG. 10 is a cross-sectional plan view showing an enlarged main part of another operating state of FIG. 7 as viewed from the VII-VII view of FIG. 9. It is the fragmentary sectional front view which looked at the closure member from the VIII-VIII view of FIG. It is the longitudinal cross-sectional view which expanded and showed the principal part of 6th Embodiment of the oil discharge mechanism of the oil filter which concerns on this invention, and was seen from IX-IX of FIG. It is the fragmentary sectional front view which looked at the closure member from the XX view of FIG. It is a longitudinal cross-sectional view which shows 7th Embodiment of the oil discharge mechanism of the oil filter which concerns on this invention, (a)-(c) has shown the operation procedure. The closing member of FIG. 12 is shown, (a) is a side view, (a) It is the rear view seen from the bb view. It is a hydraulic circuit diagram which shows schematically the hydraulic circuit of the conventional forklift. It is a longitudinal cross-sectional view which shows the structure of the conventional relief valve. It is a longitudinal cross-sectional view which shows the operating state of the relief valve of FIG. It is a side view inside a forklift truck which shows the attachment position of the conventional relief valve. It is a side view inside a forklift truck which shows other attachment positions of the conventional relief valve.

  An embodiment of an oil discharge mechanism of an oil filter according to the present invention will be described with reference to FIGS. In all the embodiments including the prior art, the same or similar components are denoted by the same reference numerals. In the following description, the conventional hydraulic circuit shown in FIG. 14 will be referred to as appropriate.

  FIG. 1 shows a first embodiment of an oil discharge mechanism of an oil filter according to the present invention. As shown in FIG. 1, the relief valve 1A includes a valve piston 2A slidably accommodated in a valve accommodation hole 104c formed in the case 120, a closing member 4A for closing the opening of the valve accommodation hole 104c, and a valve accommodation A coil spring 3 accommodated between the valve piston 2A and the closing member 4A in the hole 104c and energizing the valve piston 2A, and a drain port 109a formed in the valve accommodation hole 104c and opened and closed by the valve piston 2A are provided. Yes. When the oil pressure applied to the pressure receiving surface 2A1 of the valve piston 2A is smaller than the set pressure, the valve piston 2A closes the drain port 109a while being pressed by the coil spring 3 and cuts the drain oil passage 109, and the oil pressure of the pressure receiving surface 2A1 is set to the set pressure. When it becomes larger, the valve piston 2A is pushed leftward in FIG. 1 against the spring force of the coil spring 3, and the valve piston 2A enters the drain position, and a part of the pressure oil passes through the drain oil passage 109 from the drain port 109a. Flow to the oil tank 100 to prevent excessive pressure rise.

  The closing member 4A is a plug screw in the illustrated example, but can also be a set pressure adjusting screw, or a plate fixed to the outer surface of the case 120 with a bolt or the like as shown in FIG. What is necessary is just to close the opening of the valve accommodating hole 104c so that the coil spring 3 can contact. An oil seal material 121 such as a gasket is interposed between the closing member 4A and the case 120.

  A through hole 4A1 penetrating in the axial direction is formed in the closing member 4A, and the pulling rod 5A extends through the through hole 4A1. An O-ring 7 is fitted in a circumferential groove 6 formed in the inner peripheral surface of the through-hole 4A1 of the closing member 4A, and the pulling rod 5A can be slid in the axial direction in a liquid-tight manner by the O-ring 7. It has become.

  A recess 8 is formed in the contact surface of the coil spring 3 of the valve piston 2 </ b> A, and the tip 5 </ b> A <b> 1 of the traction rod 5 </ b> A is accommodated in the recess 8 of the valve piston 2. The tip portion 5A1 of the pulling rod 5A is formed in a bowl shape. The tip 5A1 of the pulling rod 5A has a bowl shape in the illustrated example, but may have a pin shape such as a split pin or other shapes.

  The tip 5A1 of the pulling rod 5A is urged to the back side of the recess 8 by the auxiliary spring 9 having a spring force smaller than that of the coil spring 3. In the illustrated example, a snap ring 10 is mounted on the inlet-side inner peripheral surface of the concave portion 8 of the valve piston 2A, and the auxiliary spring 9 is in contact with the snap ring 10 between the hooked tip portion 5A1 and the snap ring 10. Is arranged. The snap ring 10 and the auxiliary spring 9 accommodate the tip portion 5A1 of the pulling rod 5A so as not to be removable from the recess 8. The recess 8 is deep enough to allow the valve piston 2A to move relative to the tip 5A1 of the pulling rod 5A, that is, to allow the valve piston 2A to move to the left in the state shown in FIG. Is formed.

  The pulling rod 5A forcibly moves the valve piston 2A to the drain position (position where the drain port 109a opens) by pulling the valve piston 2A against the spring force of the coil spring 3 from the outside of the relief valve 1A. be able to. In order to hold the valve piston 2A forcibly moved to the drain position at that position, holding means 12A for holding the tow rod 5A at a predetermined position is provided.

  The holding means 12 </ b> A can include a locking pin 12 a that locks the pulling rod 5 </ b> A and the closing member 4. The locking pin 12a can be, for example, a beta pin or a split pin. By inserting the locking pin 12a into a pin hole 12b provided in the pulling rod 5A, the locking pin 12a is locked to the outer surface of the closing member 4A and resists the spring force of the coil spring 3. Thus, the traction rod 5A can be held at a predetermined position, and the valve piston 2A can be held at the drain position.

  In FIG. 1, a beta pin as an example of the locking pin 12a is inserted into a pin hole 13 formed in the pulling rod 5A. The pin hole 13 is used to lock the locking pin 12a during normal operation of the relief valve 1A. It is a pin hole for inserting.

  A pin hole into which the spring pin 14 is inserted is formed at the rear end portion of the pulling rod 5A. The spring pin 14 functions as a stopper so that the pulling rod 5A is not drawn into the through hole 4A1 of the closing member 4A due to the action of the coil spring 3 when the locking pin 12a is removed from the pulling rod 5A. As long as it can function as a stopper, it is not limited to a spring pin, and can be a hook-shaped portion or other forms.

  According to the oil discharge mechanism of the oil filter having the above configuration, when replacing the filter element of the oil filter 105 (FIG. 14), first, the pump 102 (FIG. 14) is stopped, and the tow rod 5A is pulled, Pull out the pulling rod 5A from the state, pull out the locking pin 12a inserted into the pin hole 13, and insert the locking pin 12a into the pin hole 12b of the pulled pulling rod 5A, so that the valve piston 2A is held in the drain position. Then, oil is discharged from the discharge port 109 to the oil tank 100. Therefore, by providing a change to the valve piston 2A and the closing member 4A of the relief valve 1A and adding the traction rod 5A, an oil discharge mechanism for the oil filter can be provided at a low cost without changing the existing oil passage. Can do.

  In the normal operation state of the relief valve (the state shown in FIG. 1) in which the forced drain operation by the tow rod 5A is not performed, the valve piston 2A can move relative to the tip portion 5A1 of the tow rod 5A. 1 is movable in the left-right direction (on the left side of the stopper pin 108) in FIG. 1, and functions as a normal relief valve. In addition, since the auxiliary spring 9 is provided, the traction rod 5A does not move to the left side of the drawing even when the valve piston 2A moves to the left side from the state of FIG. 1 according to the hydraulic pressure when the relief valve 1A is in a normal operation state. A certain position can be maintained. Therefore, even if the valve piston 2A moves left and right due to the hydraulic pressure received by the pressure receiving surface 2A1, the traction rod 5A can maintain a fixed position.

  FIG. 3 shows a second embodiment of the oil discharge mechanism of the oil filter according to the present invention. The relief valve 1B of the second embodiment is different from the first embodiment in that the auxiliary spring 9 shown in the first embodiment is not provided in the valve piston 2A. In the second embodiment, the cost can be reduced by omitting the auxiliary spring 9 of the first embodiment, but the traction rod 5A also moves back and forth in the axial direction by the movement of the valve piston 2A during the normal operation of the relief valve 1B. (Movement in the horizontal direction in the figure) may occur.

  4 and 5 show a third embodiment of the oil discharge mechanism of the oil filter according to the present invention. In the third embodiment, a through hole 2C1 is formed in the valve piston 2C, the pulling rod 5C passes through the through hole 2C1 of the valve piston 2C, and the locking portion 5C1 that locks the pressure receiving surface 2C2 of the valve piston 2C is used as the pulling rod. It is provided at the tip of 5C. The through hole 2C1 is designed so that a gap between the through hole 2C1 and the traction rod 5C is as small as possible. The locking portion 5C1 can be filled with a spring pin or the like formed in a pin hole in the pulling rod 5C and inserted into the pin hole. Further, the holding means 12C (FIG. 5) capable of holding the valve piston 2C in the drain position by holding the pulling rod 5C in a predetermined position against the spring force of the coil spring 3 has a circumferential groove in the rear part of the pulling rod 5C. 15 is formed, a boss portion 4C1 is formed in the closing member 4C, a pin hole 16 is formed therein, and a locking pin 17 such as a beta pin (see FIG. 5) is inserted into the pin hole 16 and locked in the circumferential groove 15 It is supposed to let you. Similar to the first and second embodiments, the circumferential groove 18 of the traction rod 5C is a circumferential groove for retaining the locking pin 17 during the normal operation of the relief valve 1C. In the third embodiment, a hook-shaped head 5C2 is formed at the rear end of the pulling rod 5C instead of the stopper pin 108 of the first and second embodiments. Other stoppers such as pins may be employed.

  FIG. 6 shows a fourth embodiment of the oil discharge mechanism of the oil filter according to the present invention. In the fourth embodiment, holding means 12D capable of holding the valve piston 2C in the drain position by holding the pulling rod 5D in a predetermined position against the spring force of the coil spring 3 is formed in the through hole 4D1 of the closing member 4D. The female screw part 19 and the male screw part 20 formed at the rear end part of the pulling rod 5D are provided. When the relief valve 1D is forcibly drained, the valve piston 2C can be forcibly retracted to the drain position by rotating the male screw part 20 in the screwing direction.

  7 to 9 show a fifth embodiment of the oil discharge mechanism of the oil filter according to the present invention. The fifth embodiment differs from the fourth embodiment in the holding means 12E that can hold the valve piston 2E in the drain position by holding the pulling rod 5E in a predetermined position against the spring force of the coil spring 3. Yes. The holding means 12E of the fifth embodiment is formed on a locking pin 21 such as a spring pin provided so as to protrude in the direction orthogonal to the axis of the pulling rod 5E, and the locking pin 21 is formed on the outer surface of the closing member 4E. Two types of linear grooves 22 (FIG. 7) and 23 (FIG. 8) with different depths are provided. In the fifth embodiment, the locking pin 21 is locked in the deeper groove 22 during normal operation of the relief valve 1E (FIG. 7). By pulling the pulling rod 5E, pulling out the locking pin 21 from the groove 22, and rotating the pulling rod 5E around the axis, the locking pin 21 is fitted into the shallow groove 23 and locked (FIG. 8). The valve piston 2C can be easily held in the drain position.

  10 and 11 show a sixth embodiment of the oil discharge mechanism of the oil filter according to the present invention. The sixth embodiment is different from the fifth embodiment in the shapes of the grooves 24 and 25 into which the locking pins 21 of the closing member 4F are fitted, which is a component of the holding means 12F. In the sixth embodiment, the groove of the closing member 4F is connected to the circumferential groove 24a along the inner peripheral surface of the through hole 4F1 on the deeper side of the deeper groove 24 than the shallower groove 25, and the through hole 4F1. A female screw portion 26 is formed in an axial range where the shallower groove 25 is formed, and a male screw portion 27 that is screwed into the female screw portion 26 is formed in the pulling rod 5F. In the sixth embodiment, the locking pin 21 is in the circumferential groove 24a during normal operation of the relief valve. The pulling rod 5 is rotated around the axis to unscrew the male screw 27 from the female screw 26, and then the locking pin 21 is removed from the deeper groove 24 and rotated around the axis of the pulling rod 5 (see FIG. The valve piston 2C (see FIG. 7) (not shown) can be held in the drain position by adding the locking pin 21 to the shallow groove 25 and locking it by adding 90 ° in the illustrated example. In the sixth embodiment, during normal operation of the relief valve, the traction rod 5F is screwed to the closing member 4F, and therefore the movement of the traction rod 5F can be prevented.

  12 and 13 show a seventh embodiment of the oil discharge mechanism of the oil filter according to the present invention. 7th Embodiment differs in the aspect of the groove | channel 28 currently formed in the closure member 4G which is a component of the holding means 12G from 6th Embodiment. In the seventh embodiment, the groove 28 is formed on the inner surface of the closing member 4G, and the locking pin 29 is also attached at a position away from the rear end of the pulling rod 5G. The groove 28 to which the locking pin 29 is locked has a substantially bowl shape as shown in FIG. In the seventh embodiment, the locking pin 29 is located away from the closing member 4G during normal operation of the relief valve. As shown in FIGS. 12A to 12B in order, the male screw portion 30 of the pulling rod 5G is unscrewed from the female screw portion 31 of the closing member 4G, and the pulling rod 5G is further pulled out so that the locking pin 29 becomes the groove 28. When the tow rod 5 is rotated about its axis when it hits the back bottom 28a of FIG. 12 (FIG. 12B) and locked to the tip 28b of the groove 28 having a substantially bowl-shaped cross section (FIG. 12C), the valve The piston 2 can be held at the drain position.

  The present invention is not limited to the above embodiment, and various modifications can be employed without departing from the spirit of the present invention.

1A, 1B, 1C, 1D, 1E, 1F, 1G Relief valve 2A, 2C Valve piston 2C1 Through hole 3 Coil spring 4A, 4C, 4D, 4E, 4F, 4G Closing member 5A, 5C, 5D, 5E, 5F, 5G Towing Rod 5C1 Locking portion 8 Recess 9 Auxiliary springs 12A, 12C, 12D, 12E, 12F, 12G Holding means 12a, 17, 21, 29 Locking pin

Claims (5)

One side is closed by a closing member, and the other side is connected to an oil passage leading to an oil filter, a valve piston that is slidably received in the valve receiving hole, and the closing member in the valve receiving hole And a relief valve comprising a coil spring interposed between the valve piston and a drain port formed in the valve housing hole and opened and closed by the valve piston;
A traction rod extending through the closing member and capable of pulling the valve piston against the spring force of the coil spring from the outside of the closing member;
Holding means capable of holding the valve piston in the drain position by holding the traction rod in a predetermined position against the spring force of the coil spring;
An oil discharge mechanism for an oil filter, comprising: A recess is formed in the valve piston;
2. The oil discharge mechanism for an oil filter according to claim 1, wherein a tip end portion of the pulling rod is housed in a recess of the valve piston in a non-removable manner while allowing relative movement of the valve piston. .   The oil discharge mechanism for an oil filter according to claim 2, wherein a tip portion of the pulling rod is urged to the back side of the recess by an auxiliary spring having a spring force smaller than that of the coil spring. A through hole is formed in the valve piston;
2. The oil filter according to claim 1, wherein the pulling rod includes a locking portion that passes through a through hole of the valve piston and locks to a pressure receiving surface of the valve piston at a distal end portion of the pulling rod. Oil discharge mechanism. The oil discharge mechanism for an oil filter according to any one of claims 1 to 4, wherein the holding means includes a locking pin that locks the pulling rod and the closing member.

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