JP2016011716A - solenoid valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size of a solenoid valve while improving controllability of output pressure.SOLUTION: In a solenoid valve 1, when output pressure Pout is introduced as feedback pressure Pfb from an output port 32 to a feedback chamber 36 through a first communication hole 45o formed in a first spool 40 and a communication path 71o formed in a first land 71 of a second spool 70; the second spool 70 resists energization force of a second spring 80 according to enhancement of the feedback pressure Pfb and slides to a side opposite to the feedback chamber 36; and the end surface on the side opposite to the feedback chamber 36 of the first land 71 and the end part on the side opposite to the feedback chamber 36 of the first communication hole 45o in the axial direction of the first spool 40 are overlapped, communication between the first communication hole 45o and the communication passage 71o is restricted, and the output pressure Pout is not introduced from the first communication hole 45 o to the feedback chamber 36.

Description

  The present invention relates to an electromagnetic part, a hollow sleeve, a spool slidably disposed in the sleeve, a feedback chamber in which an output pressure from the output port is introduced as a feedback pressure and a feedback force is applied to the spool. Relates to a solenoid valve including

  Conventionally, as this type of solenoid valve, a first feedback chamber into which an output pressure is introduced from an output port, a second feedback chamber connected to the first feedback chamber via a communication passage, and a spool are incorporated. And a blocking mechanism that opens and closes the communication passage in accordance with the output pressure is known (for example, see Patent Document 1). In this solenoid valve, when the output pressure is less than a predetermined pressure, the communication passage is opened by the shut-off mechanism, and the output pressure is introduced as the feedback pressure into the first and second feedback chambers. When the output pressure is equal to or higher than the predetermined pressure, The communication passage is closed by the shut-off mechanism, and the output pressure is introduced as the feedback pressure only in the first feedback chamber. As a result, the feedback force acting on the spool in the high hydraulic pressure output region (non-pressure adjusting region) is reduced, and the suction force (driving force) required for the solenoid portion that presses the spool in the direction against the feedback force is reduced. Therefore, it is possible to reduce the size of the solenoid part and thus the solenoid valve.

  In addition, if a shut-off mechanism that switches the feedback force between the two levels is used as described above, the feedback force from the first feedback chamber can be applied to the spool even in the high hydraulic pressure output region. The output pressure can be quickly reduced at the time of transition from the high hydraulic pressure output region to the low hydraulic pressure output region (pressure adjustment region) as compared with the case where the force is completely cut off. As a result, when the transition from the low hydraulic pressure output region to the high hydraulic pressure output region increases and the transition from the high hydraulic pressure output region to the low hydraulic pressure output region increases, the output pressure increases stepwise by reducing the feedback force acting on the spool. Thus, it is possible to suppress the occurrence of hysteresis in the output pressure characteristics.

JP 2012-202435 A

  However, although the above-described conventional solenoid valve can suppress the occurrence of hysteresis in the characteristics of the output pressure, in order to further improve the controllability of the output pressure, the hysteresis is not generated as much as possible. It is preferable. The conventional solenoid valve has a housing (partition member) having two feedback chambers and a communication passage, a ball for opening and closing the communication passage, a base connected to the ball, and a spring for biasing the base. In order to reduce the size of the entire device, there is still room for improvement. Have.

  Therefore, the main object of the present invention is to reduce the size of the solenoid valve while further improving the controllability of the output pressure.

  The electromagnetic valve according to the present invention employs the following means in order to achieve the main object.

The solenoid valve according to the present invention is:
An electromagnetic part, a hollow sleeve having an input port and an output port, and a communication between the input port and the output port according to a force from the electromagnetic part and a communication between the input port and the output port. An electromagnetic valve including a first spool for releasing the output and a feedback chamber in which an output pressure from the output port is introduced as a feedback pressure and a feedback force is applied to the first spool;
A second spool that opens at both end faces in the axial direction and includes a land including a communication path formed so that one end communicates with the feedback chamber, and is slidably disposed in the first spool;
Urging means for urging the second spool toward the feedback chamber with respect to the first spool;
The first spool has a communication hole for communicating the output port with the other end of the communication path of the land,
The second spool is configured to respond to an increase in the feedback pressure introduced from the output port into the feedback chamber through the communication hole of the first spool and the communication path of the land. The first spool is slid against the urging force of the urging means so as to release the communication between the communication hole and the communication path of the land.

  In this electromagnetic valve, the output pressure is introduced into the feedback chamber as a feedback pressure from the output port through the communication hole formed in the first spool and the communication passage formed in the land of the second spool. The second spool resists the urging force of the urging means so as to limit the communication between the communication hole of the first spool and the communication path formed in the land of the second spool in response to an increase in the feedback pressure. Then, it slides on the opposite side of the feedback chamber so that the output pressure is not introduced into the feedback chamber from the communication hole. Thereby, in the high hydraulic pressure output region where the output pressure increases, the feedback force acting on the first spool can be held substantially constant so as not to increase with the increase in the output pressure. As a result, the feedback force acting on the first spool is not changed between the transition from the low hydraulic pressure output region where the output pressure is low to the high hydraulic pressure output region and the transition from the high hydraulic pressure output region to the low hydraulic pressure output region. As a result, it is possible to prevent hysteresis from occurring in the output pressure characteristics as much as possible. Further, by holding the feedback force acting on the first spool substantially constant in the high hydraulic pressure output region, the attraction force (driving force) required for the electromagnetic part is reduced, and the electromagnetic part is downsized. Is possible. Further, in this solenoid valve, the shaft length can be shortened as compared with the solenoid valve having a plurality of feedback chambers, and an increase in the number of parts and a complicated structure can be suppressed more favorably. Therefore, according to this solenoid valve, the size of the solenoid valve can be reduced while further improving the controllability of the output pressure.

Moreover, the other solenoid valve according to the present invention is:
An electromagnetic part, a hollow sleeve having an input port and an output port, and a communication between the input port and the output port according to a force from the electromagnetic part and a communication between the input port and the output port. A spool for releasing the output, a first feedback chamber in which an output pressure from the output port is introduced as a feedback pressure and a feedback force is applied to the spool, and the feedback pressure is introduced through the first feedback chamber. And a second feedback chamber for applying a feedback force to the spool,
A ball chamber communicating with the second feedback chamber is defined in the spool, a communication hole communicating the first feedback chamber and the ball chamber, and a drain hole for draining hydraulic oil from the ball chamber; A partition member having
A plunger that is slidably disposed in the spool so as to approach and separate from the ball chamber and receives the output pressure on the opposite side of the ball chamber;
Biasing means for biasing the plunger away from the ball chamber with respect to the spool;
A ball disposed in the ball chamber and connected to the plunger, and selectively closing the communication hole and the drain hole as the plunger slides;
The first pressure receiving surface of the ball that receives the feedback pressure from the first feedback chamber when the communication hole is closed by the ball and the second feedback chamber communicates with the drain hole via the ball chamber. The feedback pressure from the first and second feedback chambers when the drain hole is closed by the ball and the second feedback chamber communicates with the first feedback chamber through the communication hole. It is smaller than the area of the 2nd pressure receiving surface of the said ball | bowl to receive.

  In this solenoid valve, when the output pressure increases, the plunger slides in the spool toward the ball chamber against the resultant force of the urging force of the urging means and the force acting on the ball by the output pressure, and is connected to the plunger. The communication hole is closed by the formed ball and the drain hole is opened, whereby the hydraulic oil in the second feedback chamber is drained. When the output pressure decreases, the plunger slides in the spool in the opposite direction to the ball chamber by the resultant force of the urging force of the urging means and the force acting on the ball by the output pressure, and the communication hole is formed by the ball. The drain hole is closed and the drain pressure is closed, and the output pressure is introduced as a feedback pressure into the second feedback chamber. As a result, the feedback force acting on the spool can be reduced by preventing the hydraulic pressure from being introduced into the second feedback chamber in the high hydraulic pressure output region where the output pressure increases, so that the attraction force (driving) required for the electromagnetic unit is reduced. Force) can be reduced, and the electromagnetic part can be miniaturized. Further, by making the area of the first pressure receiving surface of the ball smaller than the area of the second pressure receiving surface, the output pressure when the introduction of the feedback pressure (output pressure) into the second feedback chamber is stopped is reduced. However, it is possible to reduce the output pressure when the introduction of the feedback pressure (output pressure) into the second feedback chamber is resumed. As a result, when the feedback force from the second feedback chamber is applied again to the spool, it is possible to suppress a sudden drop in the output pressure, so that the controllability of the output pressure can be further improved. It becomes. As a result, this solenoid valve can be downsized while further improving the controllability of the output pressure.

It is a fragmentary sectional view showing an electromagnetic valve concerning one embodiment of the present invention. It is a fragmentary sectional view for demonstrating operation | movement of the solenoid valve of FIG. It is a fragmentary sectional view for demonstrating operation | movement of the solenoid valve of FIG. It is a graph which shows the relationship between the solenoid electric current and output pressure in the solenoid valve of FIG. It is a fragmentary sectional view showing an electromagnetic valve concerning other embodiments of the present invention. It is sectional drawing which shows the switching mechanism contained in the solenoid valve of FIG. It is sectional drawing which shows the switching mechanism contained in the solenoid valve of FIG. 6 is a chart showing the relationship between solenoid current and output pressure in the solenoid valve of FIG. 5.

  Next, the form for implementing this invention is demonstrated, referring drawings.

  FIG. 1 is a partial cross-sectional view showing a solenoid valve 1 according to an embodiment of the present invention. The electromagnetic valve 1 shown in the figure is configured as a normally closed linear solenoid valve used for hydraulic control of a clutch or a brake incorporated in an automatic transmission for a vehicle, for example. As shown in FIG. 1, the solenoid valve 1 includes a solenoid unit (electromagnetic unit) 10 and a valve unit 20 that is driven by the solenoid unit 10 and regulates and outputs the hydraulic pressure.

  The solenoid unit 10 includes a fixed core, a coil arranged so as to surround the fixed core, a plunger (none of which is shown) arranged inside the fixed core so as to be movable in the axial direction, and the plunger. A shaft 11 that moves to the bottom, a bottomed cylindrical case 12 that accommodates the shaft 11 and the like, and a plunger is sucked by a magnetic flux generated by energization of the coil. Move to the side.

  As shown in FIG. 1, the valve portion 20 is incorporated in a valve body having a plurality of oil passages, and has a hollow cylindrical sleeve 30 whose one end is fixed to the solenoid portion 10, and a slidable arrangement within the sleeve 30. The hollow cylindrical first spool 40, the end plate 50 screwed to the other end of the sleeve 30, and the first spool 40 are disposed between the end plate 50 and the solenoid part. A first spring 60 biased toward the 10 side, a second spool 70 slidably disposed in the first spool 40, and the second spool 70 opposite to the valve portion 20 with respect to the first spool 40. And a second spring (biasing means) 80 for urging the spring. In the electromagnetic valve 1, the biasing force of the first spring 60 can be adjusted by adjusting the screwing amount of the end plate 50.

  The sleeve 30 includes an input port 31 to which a hydraulic pressure (hydraulic fluid) serving as a source pressure is supplied, an output port 32 that is formed in the vicinity of the input port 31 and outputs a regulated hydraulic pressure, and an output port 32. It has the 1st drain port 33 formed adjacent, and the 2nd drain port 34 formed in the solenoid part 10 side rather than the 1st drain port 33. In addition, the sleeve 30 defines a communication chamber 35 for communicating the input port 31 and the output port 32 with each other and for communicating the output port 32 and the first drain port 33 with each other with the first spool 40. Further, the sleeve 30 is provided with a feedback chamber 36 in which the output pressure Pout from the output port 32 is introduced as the feedback pressure Pfb and a feedback force is applied to the first spool 40 in a direction to reduce the opening degree of the input port 310. Define with first spool 40. In the present embodiment, the feedback chamber 36, the input port 31, the output port 32, the first drain port 33, and the second drain port 34 are arranged in this order from the end plate 50 side toward the solenoid unit 10.

  The first spool 40 is disposed on the end plate 50 side with respect to the first land 41, the second land 42 disposed on the end plate 50 side with respect to the first land 41, and the second land 42. Between the first land 41 and the second land 42, the third land 43 having an outer diameter smaller than that of the land 42, the first reduced diameter portion 44 formed on the solenoid part 10 side of the first land 41, and The second reduced diameter portion 45 is formed, and the third reduced diameter portion 46 is formed between the second land 42 and the third land 43. The first spool 40 is disposed in the sleeve 30 such that a cap 91 attached to the end of the third reduced diameter portion 46 contacts the tip of the shaft 11 included in the solenoid unit 10.

  The first land 41 is formed so that the first drain port 33 formed in the sleeve 30 can be opened and closed as the first spool 40 slides. The second land 42 is formed so that the input port 31 formed in the sleeve 30 can be opened and closed as the first spool 40 slides. Further, the third land 43 is formed in a bottomed cylindrical shape, and a first spring 60 is disposed between the inner bottom surface and the end plate 50.

  The first reduced diameter portion 44 is formed to have a smaller outer diameter than the first land 41. The second reduced diameter portion 45 is formed such that the outer diameter gradually decreases from the first land 41 toward the second land 42 and the outer diameter gradually increases from the middle toward the first land 41. The communication chamber 35 is defined between the second lands 41 and 42 in the axial direction and around the second reduced diameter portion 45. The third reduced diameter portion 46 is formed so as to have an outer diameter smaller than that of the second and third lands 42, 43, and is between the second and third lands 42, 43 in the axial direction and the third diameter. The feedback chamber 36 is defined around the reduced diameter portion 46.

  The first spool 40 has a first hollow portion 47 extending in the axial direction inside the first spool 40, and extends from the first hollow portion 47 toward the solenoid portion 10 and has a larger diameter than the first hollow portion 47. 2 hollow portions 48. The first reduced diameter portion 44 of the first spool 40 is formed with a drain hole 44o that allows the second hollow portion 48 of the first spool 40 and the second drain port 34 formed in the sleeve 30 to communicate with each other. Further, a first communication hole 45o is formed in the second reduced diameter portion 45 of the first spool 40 so as to be able to communicate with the communication chamber 35 (and the output port 32). Further, a second communication hole 46 o for communicating the first hollow portion 47 of the first spool 40 and the feedback chamber 36 is formed in the third reduced diameter portion 46 of the first spool 40. A screw portion (not shown) is formed on the inner periphery of the third land 43, and the cap 92 is screwed to the screw portion. Thus, the first and second hollow portions 47 and 48 are closed from both sides by the caps 91 and 92 attached to the first spool 40.

  The second spool 70 is slidably disposed in the first and second hollow portions 47 and 48 of the first spool 40. The second spool 70 has a reduced diameter formed between the first land 71, the second land 72 disposed closer to the solenoid unit 10 than the first land 71, and the first and second lands 71, 72. A portion 73 and a reduced diameter portion 74 that extends from the first land 71 toward the end plate 50 and can abut on the tip of the cap 92. In the present embodiment, the second spring 80 is disposed in the second hollow portion 48 of the first spool 40 so as to be positioned between the second land 72 and the cap 91, and the second spool 70 is connected to the first spool 40. Against the feedback chamber 36 side.

  The first land 71 is formed so as to be able to open and close the first communication hole 45o formed in the first spool 40 as the second spool 70 slides. In addition, the first land 71 is formed with a communication path 71o that opens at both end faces of the first land 71 in the axial direction of the second spool 70. In the present embodiment, the communication path 71 o is formed in the first land 71 so as to be inclined with respect to the axial direction of the second spool 70. Thereby, compared with the case where the said communicating path 71o is formed so that it may extend in the axial direction of the 2nd spool 70, the intensity | strength of the 1st land 71 can be ensured more favorably. One end of the communication passage 71 o communicates with the feedback chamber 36 via the first hollow portion 47, and the other end can communicate with the first communication hole 45 o via the first hollow portion 47.

  As shown in FIG. 1, the second land 72 is formed on the second spool 70 so as to extend between the first hollow portion 47 and the second hollow portion 48 in the attached state. Further, a part of the second land 72 on the reduced diameter portion 73 side includes a pair of flat portions 72h facing each other and a pair of sliding contact portions 72c extending in a circular arc shape between the pair of flat portions 72h and facing each other. The two-surface width portion 72a having the following is formed. That is, the second land 72 is formed such that a slight gap is formed between the pair of flat surface portions 72 h of the two-surface width portion 72 a and the inner peripheral surface of the first spool 40.

  The first spool 40 and the second spool 70 define an oil passage 100 between the second land 72 and the first land 71 in the axial direction. The oil passage 100 can communicate with the feedback chamber 36 via the communication path 71o of the first land 71 and the second communication hole 46o of the first spool 40. Further, the oil passage 100 can communicate with the first communication hole 45 o of the first spool 40. As a result, the communication chamber 35, that is, the output port 32 and the feedback chamber 36 are connected to the first communication hole 45o of the first spool 40, the oil passage 100, the communication passage 71o of the first land 71, and the second communication hole of the first spool 40. It is possible to communicate via 46o.

  Next, the operation of the electromagnetic valve 1 configured as described above will be described.

  When the solenoid current I applied to a coil (not shown) of the solenoid unit 10 is 0, the first spool 40 is pressed against the moving end on the solenoid unit 10 side by the biasing force of the first spring 60 as shown in FIG. The first drain port 33 is opened by the first land 41 of the first spool 40 and the input port 31 is closed by the second land 42. As a result, when the solenoid current I is 0, the communication between the input port 31 and the output port 32 is interrupted, and the first drain port 33 and the communication chamber 35 are communicated, as shown in FIG. The output pressure Pout becomes 0. At this time, as shown in FIG. 1, the second spool 70 is maintained in a state where the tip of the reduced diameter portion 74 is pressed against the cap 91 by the urging force of the second spring 80.

  When energization of the coil of the solenoid unit 10 is started, a plunger (not shown) of the solenoid unit 10 and the shaft 11 are sucked in the axial direction toward the valve unit 20, whereby the first spool 40 is pressed by the shaft 11. Thus, it moves toward the end plate 50 against the urging force of the first spring 60. As a result, as the solenoid current I applied to the coil increases, the input port 31 is gradually opened by the second land 42 and flows into the output port 32 from the input port 31 through the communication chamber 35. As the amount of oil increases, the first drain port 33 is gradually closed by the first land 41 and the amount of hydraulic oil drained from the communication chamber 35 through the first drain port 33 gradually decreases. I will do it.

  At this time, the hydraulic oil in the communication chamber 35 is introduced into the first hollow portion 47, that is, the oil passage 100 through the first communication hole 45 o of the first spool 40. The hydraulic oil introduced into the oil passage 100 is further fed to the feedback chamber 36 through the communication passage 71o formed in the second land 72 of the second spool 70 and the second communication hole 46o of the first spool 40. be introduced. As a result, the output pressure Pout is introduced into the feedback chamber 36 as the feedback pressure Pfb, and feedback according to the pressure difference caused by the outer diameter difference (pressure receiving area difference) between the second land 42 and the third land 43 of the first spool 40. A force acts on the first spool 40. That is, the force to the end plate 50 side by the solenoid unit 10, the biasing force to the solenoid unit 10 side by the first spring 60, and the feedback force to the solenoid unit 10 side act on the first spool 40. As a result, the output pressure Pout output from the output port 32 corresponds to the solenoid current I in the low hydraulic pressure output region (pressure adjustment region) until the solenoid current I reaches the predetermined value I1, as shown by the solid line in FIG. As it increases, it increases linearly relatively slowly. Further, the feedback pressure Pfb increases following the output pressure Pout.

  Further, when the output pressure Pout is introduced into the feedback chamber 36 as the feedback pressure Pfb, the first land 71 of the second spool 70 disposed in the first hollow portion 47 of the first spool 40 also receives the feedback pressure Pfb. The feedback force to the solenoid unit 10 side also acts on the second spool 70. As a result, when the feedback pressure Pfb, that is, the output pressure Pout increases, the second spool 70 slides in the first spool 40 against the urging force of the second spring 80, and the first land 71 causes the first spool 71 to slide. The 40 first communication holes 45o are gradually closed.

  When the solenoid current I reaches the predetermined value I1 and the feedback pressure Pfb, that is, the output pressure Pout reaches the predetermined pressure P1, as shown in FIG. 2, the end face of the first land 71 opposite to the feedback chamber 36 (FIG. 2). And the end of the first communication hole 45o opposite to the feedback chamber 36 in the axial direction of the first spool 40 overlap with each other when viewed from the radial direction of the electromagnetic valve 1, so that the first spool 70 The first communication hole 45 o is closed by the land 71. As a result, the communication between the first communication hole 45o and the oil passage 100, that is, the communication between the first communication hole 45o and the communication path 71o formed in the first land 71 is restricted (the communication between both is substantially released. The introduction amount of the output pressure Pout as the feedback pressure Pfb to the feedback chamber 36 is rapidly reduced. In the present embodiment, the predetermined pressure P1 is set to a value slightly smaller than, for example, a hydraulic pressure required when the clutch or brake to which the output pressure Pout is supplied from the electromagnetic valve 1 is completely engaged.

  As a result, as indicated by a broken line in FIG. 4, after the solenoid current I becomes equal to or greater than the predetermined value I1, it is possible to restrict the feedback pressure Pfb from increasing as the output pressure Pout increases. Therefore, after the solenoid current I reaches the predetermined value I1, the force from the solenoid unit 10 acting on the first spool 40 and the force of the first spring 60 are compared with the case where the solenoid current I is less than the predetermined value I1. As the difference between the urging force and the feedback force increases, the first spool 40 quickly moves to the moving end on the end plate 50 side, and the opening of the input port 31 is maximized (see the state shown in FIG. 3). ). As a result, as shown in FIG. 4, the output pressure Pout increases stepwise up to the maximum pressure Pmax, and is maintained at the maximum pressure Pmax in a high hydraulic pressure output region (non-pressure adjusting region) where the solenoid current I is equal to or greater than the predetermined value I1. Is done.

  By the way, as described above, even after the first communication hole 45o of the first spool 40 is closed by the first land 71 and the output pressure Pout reaches the maximum pressure Pmax, the oil passage 100 has the first spool 40 in the oil passage 100. The hydraulic oil leaks from the first communication hole 45o through a slight gap between the inner peripheral surface and the outer peripheral surface of the first land 71. Therefore, even after the first communication hole 45o of the first spool 40 is closed by the first land 71, the feedback pressure Pfb actually increases slightly with the increase in the solenoid current I. As a result, as shown in FIG. 3, the second spool 70 slides against the urging force of the second spring 80 as the feedback pressure Pfb increases, and is opposite to the feedback chamber 36 of the first land 71. The side end surface moves to the second spring 80 side from the end portion of the first communication hole 45o. As a result, the hydraulic oil is prevented from leaking from the first communication hole 45 o into the oil passage 100 through the gap between the first spool 40 and the first land 71.

  Then, the solenoid valve 1 according to the present embodiment is configured such that, after the output pressure Pout reaches the maximum pressure Pmax and before the solenoid current I reaches the maximum value Imax, as shown in FIG. The hollow portion 48 is configured to communicate with each other via the two-surface width portion 72 a of the second land 72 of the second spool 70. That is, even when the first communication hole 45 o of the first spool 40 is closed by the first land 71, the hydraulic oil leaks into the oil passage 100 through the gap between the first spool 40 and the first land 71. It is difficult to completely shut off. Based on this, the solenoid valve 1 allows at least part of the hydraulic oil that leaks into the oil passage 100 from the gap between the pair of flat surface portions 72h of the two-surface width portion 72a and the inner peripheral surface of the first spool 40. The second hollow portion 48 can be drained through the gap. In this way, by draining at least part of the hydraulic oil that leaks into the oil passage 100 into the second hollow portion 48, the feedback pressure Pfb in the feedback chamber 36 is increased after the solenoid current I reaches the predetermined value I1. It is possible to better suppress the continuous increase. Therefore, in the solenoid valve 1, the feedback pressure Pfb in the feedback chamber 36 can be kept substantially constant as shown in FIG. 4 in the high hydraulic pressure output region (non-pressure regulating region), and the first spool 40 is shown in FIG. It can be stably maintained in the state shown. The hydraulic oil drained to the second hollow portion 48 is discharged to the outside of the valve portion 20 through the drain hole 44o formed in the first spool 40 and the second drain port 34 formed in the sleeve 30. Is done.

  On the other hand, when the solenoid current I decreases again from the maximum value Imax to less than the predetermined value I1, the biasing force and feedback force of the first spring 60 acting on the first spool 40 are applied from the solenoid unit 10 to the first spool 40. By becoming larger than force, the 1st spool 40 moves to the state shown in FIG. 2 rapidly, and the opening degree of the input port 31 reduces rapidly. As a result, as shown in FIG. 4, the output pressure Pout decreases stepwise from the maximum pressure Pmax, and then the opening degree of the input port 31 gradually decreases as the solenoid current I decreases, and the communication chamber 35 And the first drain port 33 gradually communicate with each other. As a result, the output pressure Pout decreases linearly relatively slowly as the solenoid current I decreases. The feedback pressure Pfb also decreases following the output pressure Pout.

  As described above, in the solenoid valve 1, the output pressure is output from the output port 32 through the first communication hole 45 o formed in the first spool 40 and the communication passage 71 o formed in the first land 71 of the second spool 70. Pout is introduced into the feedback chamber 36 as the feedback pressure Pfb. Further, the second spool 70 slides on the opposite side to the feedback chamber 36 against the urging force of the second spring 80 as the feedback pressure Pfb increases. When the end surface of the first land 71 opposite to the feedback chamber 36 and the end portion of the first communication hole 45o opposite to the feedback chamber 36 in the axial direction of the first spool 40 overlap, the first communication hole The communication between 45o and the communication passage 71o is restricted (substantially released), and the output pressure Pout is not introduced into the feedback chamber 36 from the first communication hole 45o (the introduction amount is rapidly reduced).

  As a result, in the high hydraulic pressure output region where the output pressure Pout increases, the feedback force acting on the first spool 40 can be held substantially constant so as not to increase with the increase in the output pressure Pout. As a result, as shown in FIG. 4, it acts on the first spool 40 at the time of transition from the low hydraulic pressure output region where the output pressure is low to the high hydraulic pressure output region and at the time of transition from the high hydraulic pressure output region to the low hydraulic pressure output region. Thus, it is possible to prevent the feedback force from changing, and to prevent hysteresis from occurring in the output pressure characteristics as much as possible. Further, by holding the feedback force acting on the first spool 40 substantially constant in the high hydraulic pressure output region, the suction force (driving force) required for the solenoid unit 10 can be reduced, and the solenoid unit 10 can be downsized. Can be achieved. Furthermore, in the solenoid valve 1, the shaft length can be shortened as compared with the solenoid valve having a plurality of feedback chambers, and the increase in the number of parts and the complexity of the structure can be suppressed more favorably. Therefore, according to the solenoid valve 1, it is possible to reduce the size while further improving the controllability of the output pressure Pout.

  Further, the first spool 40 of the solenoid valve 1 has a drain hole 44 o formed on the opposite side of the feedback chamber 36 from the first communication hole 45 o, and the second spool 70 is drained more than the first land 71. The second land 72 is formed so as to be close to the hole 44o. The second land 72 defines an oil passage 100 communicating with the feedback chamber 36 through the communication passage 71o together with the first land 71 and the first spool 40, and the output pressure Pout as the solenoid current I increases. Is formed in the second spool 70 so as to allow the oil passage 100 and the drain hole 44o to communicate with each other. As a result, the communication between the first communication hole 45o formed in the first spool 40 and the communication passage 71o formed in the first land 71 is substantially released by the second spool 70 (the communication between both is restricted). Even if the hydraulic oil leaks into the oil passage 100 from the gap between the first spool 40 and the second spool 70 after the output pressure Pout reaches the maximum pressure Pmax, the operation leaked into the oil passage 100 The oil can be discharged from the drain hole 44 o formed in the first spool 40. As a result, it is possible to suppress the oil pressure in the feedback chamber 36 from continuing to increase after the output pressure Pout reaches the maximum pressure Pmax, so that the feedback force acting on the first spool 40 can be stably maintained in a substantially constant state. The maximum pressure Pmax can be stably supplied from the electromagnetic valve 1 to the supply target (for example, a hydraulic servo of the clutch). However, the drain hole 44o and the second land 72 may be omitted depending on the amount of hydraulic oil that leaks into the oil passage 100 from the gap between the first spool 40 and the second spool 70.

  In the solenoid valve 1, the second land 72 has a two-surface width portion 72 a including a pair of opposed flat portions 72 h, and the two-surface width portion 72 a increases with the increase in the solenoid current I. After the output pressure Pout output from the first pressure Pmax reaches the maximum pressure Pmax, the oil passage 100 and the drain hole 44o are communicated with each other through a gap between the pair of flat surface portions 72h and the inner peripheral surface of the first spool 40. Is done. Thus, after the output pressure Pout reaches the maximum pressure Pmax, the hydraulic oil that has leaked into the oil passage 100 can be guided to the drain hole 44o through the pair of flat portions 72h of the second land 72. . Further, since the portions other than the pair of flat surface portions 72h of the two-surface width portion 72a, that is, the pair of sliding contact portions 72c can always be slidably contacted with the inner peripheral surface of the first spool 40, the second spool 40 The land 72, that is, the second spool 70 can be supported more stably. However, the two-sided width portion 72a is omitted from the second land 72, and after the output pressure Pout reaches the maximum pressure Pmax, at least until the solenoid current I reaches the maximum value Imax, the feedback chamber of the second land 72 is provided. The second land 72 may be formed so that a part of the hydraulic oil in the oil passage 100 is drained by moving the end portion on the 36 side into the second hollow portion 48.

  Further, in the solenoid valve 1, the communication path 71o is formed in the first land 71 so as to be inclined with respect to the axial direction. Thereby, durability of the 1st land 71 can be secured more favorably. However, depending on the size (outer diameter) of the first land 71, the communication path 71 o may be formed to extend along the axial direction of the first land 71.

  FIG. 5 is a partial cross-sectional view showing a solenoid valve 1B according to another embodiment of the present invention. The electromagnetic valve 1B has a valve portion 200 in place of the valve portion 20 of the electromagnetic valve 1 described above. As shown in FIG. 1, the valve unit 200 is incorporated in a valve body having a plurality of oil passages, and has a hollow cylindrical sleeve 300 whose one end is fixed to the solenoid unit 10, and a slidable arrangement within the sleeve 300. The hollow cylindrical spool 400, the end plate 500 screwed to the other end of the sleeve 300, and the spool 400 are arranged between the end plate 500 and urge the spool 400 toward the solenoid unit 10. A first spring 600. In the electromagnetic valve 1B as well, the biasing force of the first spring 600 can be adjusted by adjusting the screwing amount of the end plate 500.

  The sleeve 300 is formed close to the input port 310 to which a hydraulic pressure (hydraulic fluid) serving as a source pressure is supplied, the output port 320 that is formed close to the input port 310 and outputs the hydraulic pressure, and close to the output port 320. And a feedback port 340 connected to the output port 320 via a feedback oil passage (not shown) formed by the inner wall of the valve body and the outer wall of the sleeve 300. The sleeve 300 defines a communication chamber 350 for connecting the input port 310 and the output port 320 to each other and the communication port 350 for connecting the output port 320 and the drain port 330 to each other together with the spool 400. Further, in the sleeve 300, the output pressure Pout output from the output port 320 is introduced as the feedback pressure Pfb, and the first and second feedback forces are applied to the spool 400 in the direction of decreasing the opening degree of the input port 310. The feedback chambers 361 and 362 are defined together with the spool 400. In the present embodiment, the input port 310, the output port 320, the drain port 330, the second feedback chamber 362, and the first feedback chamber 361 are arranged in this order from the end plate 500 side toward the solenoid unit 10.

  The spool 400 is disposed closer to the solenoid unit 10 than the first land 410, the second land 420 disposed closer to the solenoid unit 10 than the first land 410, and the second land 420. A third land 430 having a larger outer diameter, a fourth land 440 disposed closer to the solenoid unit 10 than the third land 430 and having a larger outer diameter than the third land 430, and the first and first The first reduced diameter portion 450 formed between the two lands 410, 420, the second reduced diameter portion 460 formed between the second and third lands 420, 430, the third and fourth lands 430, And a third reduced diameter portion 470 formed between 440.

  The first land 410 is formed in a bottomed cylindrical shape, and a first spring 600 is disposed between the inner bottom surface of the first land 410 and the end plate 500. The first land 410 is formed so that the input port 310 formed in the sleeve 300 can be opened and closed as the spool 400 slides. The second land 420 is formed so that the drain port 330 formed in the sleeve 300 can be opened and closed as the spool 400 slides.

  The first reduced diameter portion 450 is formed so that the outer diameter decreases from the first land 410 toward the second land 420, and the outer diameter decreases from the second land 420 toward the first land 410. The outer diameter is gradually reduced from the first land 410 toward the second land 420 and the outer diameter is gradually increased from the middle toward the first land 410. The communication chamber 350 is defined around the first reduced diameter portion 450 in the axial direction. The second reduced diameter portion 460 is formed to have a smaller outer diameter than the second and third lands 420 and 430, and together with the second and third lands 420 and 430 and the sleeve 300, the second feedback chamber 362. Is defined. The third reduced diameter portion 470 is formed to have an outer diameter smaller than that of the third and fourth lands 430 and 440, and together with the third and fourth lands 430 and 440 and the sleeve 300, the first feedback chamber 361. Is defined.

  The spool 400 has a first hollow portion 480 extending in the axial direction in the spool 400, and a second hollow portion extending from the first hollow portion 480 toward the solenoid portion 10 and having a larger diameter than the first hollow portion 480. Part 490 (see FIGS. 6 and 7). The first reduced diameter portion 450 of the spool 400 is formed with a communication hole 450o for communicating the communication chamber 350 and the first hollow portion 480 to introduce the output pressure Pout into the first hollow portion 480. . In addition, a communication hole 460 o for communicating the second feedback chamber 362 and the second hollow portion 490 is formed in the second reduced diameter portion 460 of the spool 400. Further, a communication hole 470 o for communicating the first feedback chamber 361 and the second hollow portion 490 is formed in the third reduced diameter portion 470 of the spool 400. In addition, the second land 420 is formed with a communication hole 420o that allows the drain port 330 and the first hollow portion 480 to communicate with each other.

  Inside the first and second hollow portions 480 and 490 of the spool 400, a switching mechanism 700 capable of switching the feedback force of the valve portion 200 between two levels of strength and weakness is housed. As shown in FIGS. 6 and 7, the switching mechanism 700 is slidably disposed in a partition member 710 that defines a ball chamber 800 in the second hollow portion 490 of the spool 400 and in the first hollow portion 480. And a plunger 720 for receiving an output pressure Pout introduced from the communication chamber 350 into the first hollow portion 480 through the communication hole 420o, and a valve body connected to the plunger 720 and disposed in the ball chamber 800. And a second spring 740 that urges the plunger 720 against the spool 400 in a direction against the output pressure Pout.

  As shown in FIGS. 6 and 7, the partition member 710 includes a first member 711 fixed to the inner peripheral surface of the fourth land 440, a second land 420, a second reduced diameter portion 460, and a third land 430. A bottomed cylindrical second member 712 fixed to the inner peripheral surface and a bottomed cylindrical base 713 fixed to the inner peripheral surface of the second member 712 are included. The first member 711 partitions an oil chamber 810 that communicates with the first feedback chamber 361 through the communication hole 470 o together with the second member 712 in the second hollow portion 490 of the spool 400. As shown in FIG. 5, the first member 711 contacts the shaft 11 of the solenoid unit 10. As shown in FIGS. 6 and 7, the second member 712 partitions the ball chamber 800 together with the base 713 in the second hollow portion 490 of the spool 400. In addition, a communication hole 712 o for communicating the ball chamber 800 and the oil chamber 810 is formed at the bottom of the second member 712. Further, a communication groove 712 a for communicating the ball chamber 800 and the second feedback chamber 362 through the communication hole 460 o of the spool 400 is formed on a part of the outer peripheral surface of the second member 712.

  As shown in FIGS. 6 and 7, the pedestal 713 includes an outer cylinder portion 713 a that is fixed to the inner peripheral surface of the second member 712 and extends from the bottom portion toward the solenoid portion 10. The pedestal 713 defines a spring chamber 820 in which the second spring 740 is disposed in the first and second hollow portions 480 and 490 of the spool 400 together with the plunger 720. Further, a drain hole 713 o for allowing hydraulic oil in the second feedback chamber 362 to flow out to the spring chamber 820 through the ball chamber 800 is formed at the bottom of the base 713.

  As shown in FIGS. 6 and 7, the plunger 720 is slidably disposed in the first hollow portion 480 and is introduced into the first hollow portion 480 from the communication chamber 350 through the communication hole 420o. A sliding portion 721 that receives the output pressure Pout and a connecting portion 722 that extends from the sliding portion 721 through the drain hole 713o of the base 713 into the ball chamber 800 and contacts (connects) the ball 730. In addition, a communication groove 721o for communicating the communication hole 420o formed in the spool 400 and the spring chamber 820 is formed on the outer peripheral surface of the sliding portion 721.

  In the present embodiment, the second spring 740 is disposed between the end surface of the sliding portion 721 of the plunger 720 on the solenoid unit 10 side and the pedestal 713, and the plunger 720 is set to the output pressure Pout with respect to the pedestal 713, that is, the spool 400. Energize in the direction of opposition. Accordingly, the force acting on the ball 730 by the output pressure Pout introduced into the ball chamber 800 from the first feedback chamber 361 through the communication hole 470o, the oil chamber 810, and the communication hole 712o, and the biasing force by the second spring 740 When the resultant force with Sp is larger than the force F acting on the plunger 720 by the output pressure Pout introduced into the first hollow portion 480 from the communication chamber 350 through the communication hole 420o, as shown in FIG. 720 is kept pressed against the end of the first hollow portion 480 on the end plate 500 side, and the ball 730 closes the opening of the outer cylindrical portion 713a of the base 713 and opens the communication hole 712o. Thereby, as shown in FIG. 6, the first feedback chamber 361 and the second feedback chamber 362 are connected to the communication hole 470o of the spool 400, the oil chamber 810, the communication hole 712o of the second member 712, the ball chamber 800, and the second member. The communication groove 712a of 712 and the communication hole 460o of the spool 400 communicate with each other. Further, the communication between the second feedback chamber 362 and the drain hole 713o of the pedestal 713 is released.

  On the other hand, the force F acting on the plunger 720 by the output pressure Pout introduced from the communication chamber 350 into the first hollow portion 480 is applied to the ball 730 by the output pressure Pout introduced from the first feedback chamber 361 into the ball chamber 800. When the resultant force and the urging force Sp by the second spring 740 are larger than the resultant force Sp, as shown in FIG. 7, the plunger 720 and the ball 730 move integrally toward the solenoid unit 10 side, and the ball 730 is moved to the second position. The communication hole 712o formed in the second member 712 is closed by contacting the bottom of the member 712, and the drain hole 713o of the base 713 is opened. As a result, the communication between the oil chamber 810 and the ball chamber 800 is released, so that the communication between the first feedback chamber 361 and the second feedback chamber 362 is released. Further, the second feedback chamber 362 communicates with the drain hole 713 o of the base 713 through the communication hole 460 o of the spool 400, the communication groove 712 a of the second member 712, and the ball chamber 800. In this way, the switching mechanism 700 can selectively close the communication hole 712o and the opening of the outer cylinder portion 713a of the pedestal 713, that is, the drain hole 713o, by the balls 730.

  In this embodiment, the opening area (first pressure receiving area) M1 (see FIG. 7) of the communication hole 712o is larger than the opening area (second pressure receiving area) M2 (see FIG. 7) of the outer cylindrical portion 713a of the base 713. For example, the opening area M1 of the communication hole 712o is set to about 1/10 to 1/20 of the opening area M2 of the outer cylinder portion 713a. Thereby, when the ball 730 closes the communication hole 712o, the area of the pressure receiving surface where the ball 730 receives the output pressure Pout through the communication hole 712o is the same as that when the ball 730 closes the drain hole 713o. The ball 730 is smaller than the area of the pressure receiving surface that receives the output pressure Pout. As a result, when the ball 730 closes the communication hole 712o rather than the force B1 acting on the ball 730 by the output pressure Pout when the ball 730 closes the drain hole 713o, the ball The force B2 acting on 730 can be reduced.

  Next, the operation of the electromagnetic valve 1B configured as described above will be described.

  When the solenoid current I applied to a coil (not shown) of the solenoid unit 10 is 0, the spool 400 is pressed against the moving end on the solenoid unit 10 side by the biasing force of the first spring 600 as shown in FIG. The input port 310 is closed by the first land 410 of the spool 400 and the drain port 330 is opened by the second land 420. As a result, when the solenoid current I has a value of 0, the communication between the input port 310 and the output port 320 is interrupted, and the drain port 330 and the communication chamber 350 are communicated. As shown in FIG. Pout has the value 0. At this time, as shown in FIGS. 5 and 6, the plunger 720 of the switching mechanism 700 is kept pressed against the end of the first hollow portion 480 on the end plate 500 side by the urging force of the second spring 740. The As a result, the drain hole 713o is closed by the ball 730, the communication hole 712o is opened, and the first feedback chamber 361 and the second feedback chamber 362 are communicated.

  When energization of the coil of the solenoid unit 10 is started, a plunger (not shown) of the solenoid unit 10 and the shaft 11 are sucked in the axial direction toward the valve unit 20, whereby the first spool 40 is pressed by the shaft 11. Thus, it moves toward the end plate 50 against the urging force of the first spring 60. As a result, as the solenoid current I applied to the coil increases, the input port 310 is gradually opened by the first land 410 and output from the input port 310 to the output port 320 through the communication chamber 350. As the amount of hydraulic oil increases (the output pressure Pout increases), the drain port 330 is gradually closed by the second land 420 and drained from the communication chamber 350 through the drain port 330. The amount of will gradually decrease. Part of the hydraulic oil output from the output port 320 is introduced into the first feedback chamber 361 via a feedback oil passage (not shown) formed in the sleeve 300 and the feedback port 340, and further, the communication hole of the spool 400. It is introduced into the second hollow portion 490, that is, into the oil chamber 810 through 470o.

  Then, until the output pressure Pout reaches the predetermined pressure P11, the switching mechanism 700 maintains the state where the drain hole 713o is closed by the ball 730 and the communication hole 712o is opened. That is, in the electromagnetic valve 1B, until the output pressure Pout reaches the predetermined pressure P11, the ball 730 acts on the ball 730 by the output pressure Pout introduced into the ball chamber 800 with the drain hole 713o closed. The resultant force of the force B1 and the urging force Sp by the second spring 740 becomes larger than the force F acting on the plunger 720 by the output pressure Pout.

  As a result, the hydraulic oil introduced into the oil chamber 810 is introduced into the ball chamber 800 through the communication hole 712o, and further from the ball chamber 800 to the communication groove 712a of the second member 712 and the spool 400. It is introduced into the second feedback chamber 362 through the communication hole 460o. As a result, the output pressure Pout is introduced into both the first and second feedback chambers 361 and 362 as the feedback pressure Pfb, and the spool 400 has an outer diameter difference (pressure receiving area difference) between the second land 420 and the third land 430. ) And a feedback force corresponding to the differential pressure generated by the difference in outer diameter between the third land 430 and the fourth land 440 acts. That is, the spool 400 includes a force applied to the end plate 50 side by the solenoid unit 10, a biasing force applied to the solenoid unit 10 side by the first spring 60, and a solenoid unit from both the first and second feedback chambers 361 and 362. A feedback force to the 10 side acts. As a result, as shown in FIG. 8, in the low hydraulic pressure output region (pressure adjustment region) until the solenoid current I reaches the predetermined value I11, the output pressure Pout output from the output port 320 is the first and second feedback. The feedback force from the chambers 361 and 362 increases linearly relatively slowly as the solenoid current I increases while following the characteristics of the state in which the feedback force is acting on the spool 400.

  On the other hand, when the solenoid current I reaches the predetermined value I11 and the output pressure Pout reaches the predetermined pressure P11, the force F acting on the plunger 720 due to the output pressure Pout causes the ball 730 to close the drain hole 713o. The output pressure Pout introduced into the chamber 800 is greater than the resultant force of the force B1 acting on the ball 730 and the urging force Sp by the second spring 740. As a result, as shown in FIG. 7, the plunger 720 slides in the spool 400 toward the ball chamber 800 against the resultant force of the force B1 acting on the ball 730 and the biasing force Sp by the second spring 740, and the plunger A communication hole 712o is closed by a ball 730 connected to 720, and a drain hole 713o is opened. Thereby, the introduction of the output pressure Pout to the second feedback chamber 362 is stopped, and the hydraulic oil in the second feedback chamber 362 is spring-loaded through the communication hole 460o, the communication groove 712a, the ball chamber 800, and the drain hole 713o. Drained into chamber 820. The hydraulic oil drained to the spring chamber 820 is discharged to the drain port 330 of the sleeve 300 through the communication groove 721o of the plunger 720 and the communication hole 420o of the spool 400.

  As a result, the spool 400 has a force applied to the end plate 50 by the solenoid 10, a biasing force applied to the solenoid 10 by the first spring 60, and feedback from the first feedback chamber 361 alone to the solenoid 10. Power acts. As a result, the feedback force acting on the spool 400 is reduced as compared with the case where the feedback force from both the first and second feedback chambers 361 and 362 acts on the spool 400, so that the spool 400 becomes closer to the end plate 500 side. And the opening of the input port 310 is maximized. Therefore, as shown in FIG. 8, the output pressure Pout increases stepwise up to the maximum pressure Pmax, and is maintained at the maximum pressure Pmax in a high hydraulic pressure output region (non-regulation region) where the solenoid current I is equal to or greater than the predetermined value I11. The

  When the solenoid current I decreases from the maximum value Imax to less than the predetermined value I22, the output pressure Pout is a characteristic in a state where the feedback force from the first feedback chamber 361 is applied to the spool 400 as shown in FIG. As the solenoid current I decreases, the voltage decreases linearly. In the solenoid valve 1B, when the solenoid current I becomes less than the current I33 smaller than the predetermined value I11 and the output pressure Pout becomes less than the predetermined pressure P22 smaller than the predetermined pressure P11, the ball 730 closes the communication hole 712o. In this state, the resultant force of the force B2 acting on the ball 730 by the output pressure Pout and the urging force Sp by the second spring 740 becomes larger than the force F acting on the plunger 720 by the output pressure Pout.

  As a result, the plunger 720 and the ball 730 are integrally moved to the end plate 500 side (the side opposite to the ball chamber 800), the drain hole 713o is closed by the ball 730, and the communication hole 712o is opened. As a result, the first feedback chamber 361 and the second feedback chamber 362 communicate with each other again through the communication hole 712o, and the communication between the second feedback chamber 362 and the drain hole 713o is released, and the second feedback chamber 362 again. The output pressure Pout is introduced to the rear. Therefore, when the solenoid current I decreases below the current I33, the feedback force from both the first and second feedback chambers 361 and 362 starts to act on the spool 400, and thereafter, output according to the decrease in the solenoid current I. The pressure Pout decreases linearly to a value 0 relatively slowly.

  As described above, when the output pressure Pout becomes equal to or higher than the predetermined pressure P11 as the solenoid current I increases, the plunger 720 resists the resultant force of the force B1 acting on the ball 730 and the biasing force Sp by the second spring 740. The inside of the spool 400 slides toward the ball chamber 800, the communication hole 712o is closed by the ball 730 connected to the plunger 720, and the drain hole 713o is opened to drain the hydraulic oil in the second feedback chamber 362. The When the output pressure Pout decreases and becomes less than the predetermined pressure P22 smaller than the predetermined pressure P11, the plunger 720 is caused by the resultant force of the force B2 acting on the ball 730 by the output pressure Pout and the biasing force Sp by the second spring 740. The inside of the spool 400 slides on the opposite side to the ball chamber 800, the drain hole 713o is closed by the ball 730, the communication hole 712o is opened, and the output pressure Pout is introduced into the second feedback chamber 362 as a feedback pressure. Is done.

  As a result, the feedback force acting on the spool 400 can be reduced by preventing the hydraulic pressure from being introduced into the second feedback chamber 362 in the high hydraulic pressure output region (non-pressure regulating region) in which the output pressure is increased. Therefore, it is possible to reduce the size of the solenoid unit 10 by reducing the suction force (driving force) required. In the solenoid valve 1B, the opening area M1 (first pressure receiving area of the ball 730) M1 of the communication hole 712o is made smaller than the opening area (second pressure receiving area of the ball 730) M2 of the outer cylindrical portion 713a of the base 713. Thus, the feedback pressure Pfb (output pressure Pout) to the second feedback chamber 362 is higher than the output pressure Pout (predetermined pressure P11) when the introduction of the feedback pressure Pfd (output pressure Pout) to the second feedback chamber 362 is stopped. The output pressure Pout (predetermined pressure P22) when the introduction of) is resumed can be reduced. Accordingly, when the feedback force from the second feedback chamber 362 is applied again to the spool 400, it is possible to suppress the output pressure Pout from being suddenly reduced, so that the controllability of the output pressure Pout is further improved. It becomes possible. As a result, the solenoid valve 1B can be downsized while further improving the controllability of the output pressure Pout.

  As described above, the solenoid valve according to the present invention includes an electromagnetic part, a hollow sleeve having an input port and an output port, a slidable arrangement in the sleeve, and a force from the electromagnetic part. A first spool for communicating with and releasing the communication between the input port and the output port; a feedback chamber in which an output pressure from the output port is introduced as a feedback pressure and a feedback force is applied to the first spool; And includes a land including a communication path that is open at both end surfaces in the axial direction and has one end communicating with the feedback chamber, and is slidably disposed in the first spool. A second spool; and biasing means for biasing the second spool toward the feedback chamber with respect to the first spool, The first spool has a communication hole that communicates the output port with the other end of the communication path of the land, and the second spool communicates the communication hole of the first spool and the communication path of the land. The biasing means is configured to release communication between the communication hole of the first spool and the communication path of the land in response to an increase in the feedback pressure introduced from the output port to the feedback chamber. It slides in the first spool against the urging force.

  In this electromagnetic valve, the output pressure is introduced into the feedback chamber as a feedback pressure from the output port through the communication hole formed in the first spool and the communication passage formed in the land of the second spool. The second spool slides on the opposite side of the feedback chamber against the biasing force of the biasing means in response to an increase in the feedback pressure, and is formed in the communication hole of the first spool and the land of the second spool. Release the communication with the communication path and stop the introduction of the output pressure to the feedback chamber. Thereby, in the high hydraulic pressure output region where the output pressure increases, the feedback force acting on the first spool can be held substantially constant so as not to increase with the increase in the output pressure. As a result, the feedback force acting on the first spool is not changed between the transition from the low hydraulic pressure output region where the output pressure is low to the high hydraulic pressure output region and the transition from the high hydraulic pressure output region to the low hydraulic pressure output region. As a result, it is possible to prevent hysteresis from occurring in the output pressure characteristics as much as possible. Further, by holding the feedback force acting on the first spool substantially constant in the high hydraulic pressure output region, the attraction force (driving force) required for the electromagnetic part is reduced, and the electromagnetic part is downsized. Is possible. Further, in this solenoid valve, the shaft length can be shortened as compared with the solenoid valve having a plurality of feedback chambers, and an increase in the number of parts and a complicated structure can be suppressed more favorably. Therefore, according to this solenoid valve, the size of the solenoid valve can be reduced while further improving the controllability of the output pressure. The solenoid valve may be a normally closed type or a normally open type.

  When the end surface of the land opposite to the feedback chamber and the end portion of the communication hole in the axial direction of the first spool overlap with the end opposite to the feedback chamber, the communication hole and the Communication with the communication path may be restricted.

  Furthermore, the first spool may have a drain hole formed so as to be separated from the feedback chamber in the axial direction from the communication hole, and the second spool may have the drain hole rather than the land. A second land formed so as to be close to the first land, and the second land defines an oil passage communicating with the feedback chamber via the communication path together with the land and the first spool. In addition, the second spool may be formed so that the oil passage and the drain hole communicate with each other after the output pressure reaches the maximum pressure. Thus, after the communication between the first communication hole of the first spool and the communication path formed in the land of the second spool is released and the output pressure becomes the maximum pressure, the gap between the first spool and the second spool Even if the hydraulic oil leaks into the oil passage, the hydraulic oil leaked into the oil passage can be discharged from the drain hole formed in the first spool. As a result, since the hydraulic pressure in the feedback chamber can be kept from increasing after the output pressure reaches the maximum pressure, the feedback force acting on the first spool is stably held in a substantially constant state, and the electromagnetic valve The maximum pressure can be stably supplied to the supply target.

  The second land may have a two-sided width portion including a pair of flat portions facing each other, and the two-sided width portion has a maximum output pressure output from the output port. Later, the oil passage and the drain hole may be communicated with each other through a gap between the pair of flat surface portions and the inner peripheral surface of the first spool. Thereby, after the output pressure reaches the maximum pressure, the hydraulic oil that has leaked into the oil passage can be guided to the drain hole via the pair of flat portions of the second land. According to such a configuration, the portions other than the pair of flat portions of the two-surface width portion can always be brought into sliding contact with the inner peripheral surface of the first spool. Can be supported more stably.

  Furthermore, the communication path may be formed in the land so as to be inclined with respect to the axial direction. Thereby, it is possible to better secure the strength of the land of the second spool having the communication path.

  Another solenoid valve according to the present invention includes an electromagnetic part, a hollow sleeve having an input port and an output port, a slidable arrangement in the sleeve, and the input according to the force from the electromagnetic part. A spool for communicating between the port and the output port and releasing the communication; a first feedback chamber in which an output pressure from the output port is introduced as a feedback pressure and a feedback force is applied to the spool; and the first In a solenoid valve including a second feedback chamber in which the feedback pressure is introduced through the feedback chamber and a feedback force is applied to the spool, a ball chamber communicating with the second feedback chamber is defined in the spool. And a communication hole for communicating the first feedback chamber and the ball chamber with the bobbin. A partition member having a drain hole for draining hydraulic oil from the fluid chamber, and is slidably disposed in the spool so as to approach and separate from the ball chamber and on the opposite side to the ball chamber. A plunger for receiving the output pressure; an urging means for urging the plunger away from the ball chamber with respect to the spool; and a plunger disposed in the ball chamber and connected to the plunger. A ball that selectively closes the communication hole and the drain hole in accordance with sliding; the communication hole is closed by the ball, and the second feedback chamber is connected to the drain hole via the ball chamber. The area of the first pressure receiving surface of the ball that receives the feedback pressure from the first feedback chamber when communicating is that the drain hole is formed by the ball. The area of the second pressure receiving surface of the ball that receives the feedback pressure from the first and second feedback chambers when the second feedback chamber communicates with the first feedback chamber through the communication hole. It is characterized by being smaller than.

  In this solenoid valve, when the output pressure increases, the plunger slides in the spool toward the ball chamber against the resultant force of the urging force of the urging means and the force acting on the ball by the output pressure, and is connected to the plunger. The communication hole is closed by the formed ball and the drain hole is opened, whereby the hydraulic oil in the second feedback chamber is drained. When the output pressure decreases, the plunger slides in the spool in the opposite direction to the ball chamber by the resultant force of the urging force of the urging means and the force acting on the ball by the output pressure, and the communication hole is formed by the ball. The drain hole is closed and the drain pressure is closed, and the output pressure is introduced as a feedback pressure into the second feedback chamber. As a result, the feedback force acting on the spool can be reduced by preventing the hydraulic pressure from being introduced into the second feedback chamber in the high hydraulic pressure output region where the output pressure increases, so that the attraction force (driving) required for the electromagnetic unit is reduced. Force) can be reduced, and the electromagnetic part can be miniaturized. Further, by making the area of the first pressure receiving surface of the ball smaller than the area of the second pressure receiving surface, the output pressure when the introduction of the feedback pressure (output pressure) into the second feedback chamber is stopped is reduced. However, it is possible to reduce the output pressure when the introduction of the feedback pressure (output pressure) into the second feedback chamber is resumed. As a result, when the feedback force from the second feedback chamber is applied again to the spool, it is possible to suppress a sudden drop in the output pressure, so that the controllability of the output pressure can be further improved. It becomes. As a result, this solenoid valve can be downsized while further improving the controllability of the output pressure. This solenoid valve may also be a normally closed type or a normally open type.

  And this invention is not limited to the said embodiment at all, and it cannot be overemphasized that a various change can be made within the range of the extension of this invention. Furthermore, the mode for carrying out the invention described above is merely a specific embodiment of the invention described in the column for solving the problem, and is described in the column for means for solving the problem. It is not intended to limit the elements of the invention.

  The present invention can be used in the electromagnetic valve manufacturing industry and the like.

  1, 1B Solenoid valve, 10 solenoid part, 11 shaft, 12 case, 20 valve part, 30 sleeve, 31 input port, 32 output port, 33 first drain port, 34 second drain port, 35 communication chamber, 36 feedback chamber , 40 1st spool, 41 1st land, 42 2nd land, 43 3rd land, 44 1st reduced diameter part, 44o drain hole, 45 2nd reduced diameter part, 45o 1st communication hole, 46 3rd reduced diameter Part, 46o second communication hole, 47 first hollow part, 48 second hollow part, 50 end plate, 60 first spring, 70 second spool, 71 first land, 71o communication path, 72 second land, 72a Surface width portion, 72c Sliding contact portion, 72h Planar portion, 73, 74 Reduced diameter portion, 80 Second spring, 91, 92 Cap, 100 Oil passage, 20 0 Valve unit, 300 sleeve, 310 input port, 320 output port, 330 drain port, 340 feedback port, 350 communication chamber, 361 first feedback chamber, 362 second feedback chamber, 400 spool, 410 first land, 420 second Land, 420o communication hole, 430 third land, 440 fourth land, 450 first reduced diameter portion, 450o communication hole, 460 second reduced diameter portion, 460o communication hole, 470 third reduced diameter portion, 470o communication hole, 480 First hollow portion, 490 Second hollow portion, 500 End plate, 600 First spring, 700 Switching mechanism, 710 Partition member, 711 First member, 712 Second member, 712a Communication groove, 712o Communication hole, 713 Base, 713a Outer cylinder, 713o drain hole, 720 plug Nja, 721 sliding portion, 721O communication groove, 722 connecting portion, 730 balls, 740 second spring 800 ball chamber, 810 the oil chamber, 820 spring chamber.

Claims (6)

An electromagnetic part, a hollow sleeve having an input port and an output port, and a communication between the input port and the output port according to a force from the electromagnetic part and a communication between the input port and the output port. An electromagnetic valve including a first spool for releasing the output and a feedback chamber in which an output pressure from the output port is introduced as a feedback pressure and a feedback force is applied to the first spool;
A second spool that opens at both end faces in the axial direction and includes a land including a communication path formed so that one end communicates with the feedback chamber, and is slidably disposed in the first spool;
Urging means for urging the second spool toward the feedback chamber with respect to the first spool;
The first spool has a communication hole for communicating the output port with the other end of the communication path of the land,
The second spool is configured to respond to an increase in the feedback pressure introduced from the output port into the feedback chamber through the communication hole of the first spool and the communication path of the land. An electromagnetic valve that slides in the first spool against the urging force of the urging means so as to release the communication between the communication hole and the communication path of the land. The solenoid valve according to claim 1,
When the end surface of the land opposite to the feedback chamber overlaps with the end portion of the communication hole in the axial direction of the first spool opposite to the feedback chamber, the communication hole and the communication path The solenoid valve is characterized in that communication with it is restricted. The solenoid valve according to claim 2,
The first spool has a drain hole formed so as to be separated from the feedback chamber in the axial direction than the communication hole,
The second spool has a second land formed closer to the drain hole than the land,
The second land defines an oil passage that communicates with the feedback chamber via the communication path together with the land and the first spool, and the oil passage and the first passage after the output pressure reaches a maximum pressure. An electromagnetic valve formed on the second spool so as to communicate with a drain hole. The solenoid valve according to claim 3,
The second land has a two-sided width portion including a pair of opposed flat portions,
After the output pressure output from the output port becomes maximum, the two-surface width portion has the oil passage and the drain hole through a gap between the pair of flat surface portions and the inner peripheral surface of the first spool. An electromagnetic valve formed so as to communicate with the electromagnetic valve. In the solenoid valve according to any one of claims 1 to 4,
The electromagnetic valve according to claim 1, wherein the communication path is formed in the land so as to be inclined with respect to the axial direction. An electromagnetic part, a hollow sleeve having an input port and an output port, and a communication between the input port and the output port according to a force from the electromagnetic part and a communication between the input port and the output port. A spool for releasing the output, a first feedback chamber in which an output pressure from the output port is introduced as a feedback pressure and a feedback force is applied to the spool, and the feedback pressure is introduced through the first feedback chamber. And a second feedback chamber for applying a feedback force to the spool,
A ball chamber communicating with the second feedback chamber is defined in the spool, a communication hole communicating the first feedback chamber and the ball chamber, and a drain hole for draining hydraulic oil from the ball chamber; A partition member having
A plunger that is slidably disposed in the spool so as to approach and separate from the ball chamber and receives the output pressure on the opposite side of the ball chamber;
Biasing means for biasing the plunger away from the ball chamber with respect to the spool;
A ball disposed in the ball chamber and connected to the plunger, and selectively closing the communication hole and the drain hole as the plunger slides;
The first pressure receiving surface of the ball that receives the feedback pressure from the first feedback chamber when the communication hole is closed by the ball and the second feedback chamber communicates with the drain hole via the ball chamber. The feedback pressure from the first and second feedback chambers when the drain hole is closed by the ball and the second feedback chamber communicates with the first feedback chamber through the communication hole. An electromagnetic valve characterized in that it is smaller than the area of the second pressure receiving surface of the ball receiving the ball.

Images