JP2018048675A - solenoid valve - Google Patents

Abstract

Provided is an electromagnetic valve capable of suppressing friction associated with axial movement of a shaft and a plunger of a solenoid unit that moves a spool with respect to a sleeve. A solenoid valve (1) includes a sleeve (2) having a valve hole (20), a spool (3) accommodated in the valve hole (20) so as to be movable in the axial direction, a solenoid (5) pressing the spool (3), and a solenoid (5). And a coil spring 42 biased to the side. The solenoid portion 5 includes a housing 61 fixed to the electromagnetic coil 50 and the sleeve 2 and serving as a magnetic path of a magnetic flux of the electromagnetic coil 50, a cylindrical plunger 7 that moves in the axial direction with respect to the housing 61, The shaft 8 moves integrally with the spool 7 and the leading end 81 abuts on the spool 3, and the inner surface 820 a of the recess 820 formed in the rear end 82 of the shaft 8 abuts on the guide hole 610 of the housing 61 in the axial direction. It has a sphere 91 accommodated as possible and a coil spring 92 for urging the sphere 91 against the rear end 82 of the shaft 8. [Selection diagram] Fig. 1

Description

  The present invention relates to an electromagnetic valve including a solenoid portion that moves a spool in an axial direction with respect to a cylindrical sleeve having a plurality of ports.

  2. Description of the Related Art Conventionally, a solenoid portion that generates electromagnetic force, a cylindrical sleeve having a valve hole, and an axial spool that moves in the axial direction within the valve hole, the sleeve is moved by the axial movement of the spool by the electromagnetic force of the solenoid portion. There is known an electromagnetic valve that adjusts the pressure of hydraulic fluid supplied from the output port to the target device (see, for example, Patent Documents 1 and 2).

  The solenoid unit includes an electromagnetic coil that generates magnetic flux by an exciting current, a housing made of a cylindrical magnetic body that holds the electromagnetic coil, and a cylindrical plunger that receives the magnetic flux of the electromagnetic coil and moves in the axial direction relative to the housing And a shaft that moves axially integrally with the plunger and whose end abuts against the spool. When an exciting current is supplied to the electromagnetic coil, the plunger moves to the sleeve side and the shaft presses the spool. When the supply of the excitation current is interrupted, the spool is pushed back to the solenoid portion side by the urging force of the spring disposed at the end portion of the sleeve. The forward / backward movement of the spool increases or decreases the flow area of the hydraulic oil in the valve hole of the sleeve, and the supply pressure of the hydraulic oil to the device to be controlled changes.

  In the electromagnetic valve described in Patent Document 1, the shaft and the plunger are fixed to the inner surface of the cylindrical first bearing bush fixed to the inner surface of the housing (solenoid case) and the solenoid core accommodated in the housing. Two bearing bushes are supported so as to be axially movable. Moreover, in the solenoid valve described in Patent Document 2, the core member is accommodated in the housing (cover member), and the shaft can move in the axial direction by the first bearing portion formed by protruding a part of the core member inward. The plunger is supported by the second bearing part formed so that a part of the cover member protrudes inward so as to be movable in the axial direction.

JP 2014-105726 A JP-A-2006-105012

  In the electromagnetic valve described in Patent Document 1, the shaft and the plunger slide on the first bearing bush and the second bearing bush, and in the electromagnetic valve described in Patent Document 2, the shaft and the plunger are the first bearing portion. And the second bearing portion is slid. Here, when the first bearing bush, the second bearing bush, the first bearing portion, and the second bearing portion are collectively referred to as a “bearing portion”, the shaft and the plunger move forward and backward in the axial direction. Friction occurs between the outer peripheral surface and the inner peripheral surface of the bearing portion. Due to this friction, stick slip may occur when the shaft and plunger move in the axial direction, and the outer peripheral surface of the shaft and plunger and the inner peripheral surface of the bearing portion may wear, resulting in increased play in the radial direction of the shaft and plunger. There is.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electromagnetic valve capable of suppressing friction associated with axial movement of a shaft of a solenoid part and a plunger that move a spool relative to a sleeve.

  In order to achieve the above object, the present invention includes a cylindrical sleeve formed with a plurality of ports through which hydraulic oil flows, and a valve hole formed in the sleeve so as to be axially movable. A spool that changes the flow path area between the ports by movement, and a solenoid portion that operates upon receiving an excitation current and presses the spool to one side in the axial direction with a pressing force according to the magnitude of the excitation current And a first urging member that urges the spool toward the solenoid part, the solenoid part being fixed to the sleeve, an electromagnetic coil that generates magnetic flux by the excitation current, and the sleeve A housing serving as a magnetic path for magnetic flux, a core member accommodated in the housing, and a cylindrical plastic member that is attracted to the core member that has received the magnetic flux and moves in the axial direction relative to the housing. A shaft whose tip is in contact with the spool and axially moves integrally with the plunger, a sphere that is movable with respect to the housing along the axial direction of the plunger, and the sphere is attached to the shaft. A second urging member for urging the rear end portion, and the movement of the sphere in a direction perpendicular to the axial direction of the plunger with respect to the housing is restricted, and the shaft is Provided is an electromagnetic valve in which movement of the sphere in a direction orthogonal to the axial direction of the plunger is restricted by housing a part of the sphere in a recess formed in the portion.

  According to the electromagnetic valve according to the present invention, it is possible to suppress friction associated with the axial movement of the shaft of the solenoid unit and the plunger that move the spool relative to the sleeve.

It is sectional drawing which shows the structural example of the solenoid valve which concerns on embodiment of this invention, (a) has shown the non-energized state, (b) has shown the energized state. It is an enlarged view which expands and shows a part in Fig.1 (a). It is an enlarged view which expands and shows other one part in Fig.1 (a). It is sectional drawing which expands and shows a part of solenoid valve which concerns on the modification 1 of embodiment. It is sectional drawing which expands and shows a part of solenoid valve which concerns on the modification 2 of embodiment.

[Embodiment]
Embodiments of the present invention will be described with reference to FIGS. In addition, although embodiment described below is shown as a suitable specific example in implementing this invention, although there are some parts which have illustrated various technical matters that are technically preferable. The technical scope of the present invention is not limited to this specific embodiment.

  FIG. 1 is a cross-sectional view showing a configuration example of a solenoid valve according to the present embodiment, in which FIG. 1 (a) shows a non-energized state and FIG. 1 (b) shows an energized state.

  The electromagnetic valve 1 includes a cylindrical sleeve 2 in which a valve hole 20 is formed, a spool 3 accommodated in the valve hole 20 of the sleeve 2 so as to be axially movable, and a first provided at one end of the sleeve 2. An urging mechanism 4 and a solenoid portion 5 that presses the spool 3 toward the first urging mechanism 4 are provided.

  The sleeve 2 is a cylindrical member formed with a plurality of ports through which hydraulic oil supplied from an unillustrated oil pump flows. More specifically, the sleeve 2 communicates with the supply port 21 to which the hydraulic oil is supplied and the supply port 21 when the solenoid unit 5 is not energized, and the hydraulic oil is controlled (for example, electronic control mounted on the vehicle). Output port 22 to be output to the actuator of the automatic transmission), a discharge port 23 that communicates with the output port 22 when the solenoid portion 5 is energized, and a part of the hydraulic oil that has flowed out of the output port 22 Has a feedback port 24 that flows in through the feedback port hole 240, an accommodating portion 25 that accommodates the first biasing mechanism 4, and a flange portion 26 for coupling to the solenoid portion 5. The supply port 21, the output port 22, the discharge port 23, and the feedback port 24 are formed at different positions in the axial direction of the valve hole 20, and penetrate the inner and outer peripheral surfaces in a part of the sleeve 2 in the circumferential direction.

  The spool 3 is a shaft-shaped member that opens and closes the supply port 21, the output port 22, the discharge port 23, and the feedback port 24 by the axial movement inside the sleeve 2, and in order from the solenoid unit 5 side, 1 land portion 31, a second land portion 32 having a larger diameter than the first land portion 31, a small diameter portion 33 between the first land portion 31 and the second land portion 32, and a third land portion 34. Have. In the present embodiment, the supply port 21 and the output port 22 communicate with each other when the solenoid valve 1 is not energized, and the discharge port 23 is closed by the third land portion 34. Further, in a state where the rated current value is supplied to the solenoid valve 1, the output port 22 and the discharge port 23 communicate with each other, and the supply port 21 is blocked by the second land portion 32.

  Feedback pressure is supplied to the small diameter portion 33 from the feedback port 24. On the end surfaces (pressure receiving surfaces) of the first land portion 31 and the second land portion 32 facing each other across the small diameter portion 33, an area difference (pressure receiving pressure) based on the outer diameter difference between the first land portion 31 and the second land portion 32 is obtained. There is an area difference). For this reason, the force which presses the spool 3 to the plug body 41 side by the feedback pressure is generated, and there is an effect of attenuating vibration when the spool 3 operates. The flow passage area between the supply port 21 and the output port 22 and the flow passage area between the output port 22 and the discharge port 23 change as the spool 3 moves in the axial direction.

  The first urging mechanism 4 is a plug body 41 that is screwed into the inner surface of the accommodating portion 25 in the sleeve 2 to close one end of the valve hole 20, and is disposed between the plug body 41 and the spool 3. 1 and a coil spring 42 as an urging member. The coil spring 42 is compressed in the axial direction and urges the spool 3 toward the solenoid portion 5 by its restoring force. The solenoid unit 5 operates upon receiving an excitation current, and presses the spool 3 to one side in the axial direction (the first urging mechanism 4 side) with a pressing force corresponding to the magnitude of the excitation current.

  The solenoid unit 5 is housed in an electromagnetic coil 50 that generates magnetic flux by an exciting current, a housing 61 that is fixed to the sleeve 2 and serves as a magnetic path of magnetic flux generated by energization of the electromagnetic coil 50, and the housing 61. The core member 62, the cylindrical plunger 7 that is attracted to the core member 62 that has received the magnetic flux and moves in the axial direction with respect to the housing 61, and the tip portion abuts against the spool 3 and moves in the axial direction integrally with the plunger 7. And a second urging mechanism 9 that urges the spool 3 to the opposite side of the first urging mechanism 4 via the shaft 8.

  The electromagnetic coil 50 is formed by winding a conducting wire such as an enameled wire, and is held by a holding member 51 made of, for example, a molded resin. The holding member 51 is provided with a connector portion 511 that protrudes from the housing 61, and a terminal (not shown) is accommodated in the connector portion 511. An exciting current is supplied to the electromagnetic coil 50 from this terminal.

  The housing 61 has a bottomed cylindrical shape that surrounds the outer peripheral side of the electromagnetic coil 50, and houses the core member 62 together with the electromagnetic coil 50. The core member 62 attracts the plunger 7 to the spool 3 side by the magnetic force of the electromagnetic coil 50. Both the housing 61 and the core member 62 are made of a soft magnetic material such as iron. The housing 61 includes a bottom 611 positioned at an end opposite to the end on the sleeve 2 side, an outer cylindrical portion 612 and an inner cylindrical portion 613 extending in the axial direction from the bottom 611, and a distal end of the outer cylindrical portion 612. And a caulking portion 614 that is caulked to the flange portion 26 of the sleeve 2. The outer cylinder portion 612 covers the entire outer periphery of the electromagnetic coil 50 in the axial direction, and the inner cylinder portion 613 is disposed on a part of the inner periphery on the bottom 611 side of the electromagnetic coil 50.

  The core member 62 includes a cylindrical main body 621, an annular protrusion 622 that protrudes from one end of the main body 621 on the bottom 611 side of the housing 61 toward the inner cylinder 613, and the other end of the main body 621. A flange portion 623 that is provided and protrudes outward from the main body portion 621 is integrally provided. The sleeve 2 is in contact with the end of the core member 62 on the flange 623 side. The flange portion 623 sandwiches the electromagnetic coil 50 in the axial direction between the bottom portion 611 of the housing 61 and abuts against the end portion of the outer cylindrical portion 612 of the housing 61. The outer peripheral surface of the annular protrusion 622 is tapered, and the end of the housing 61 on the inner cylinder 613 side is thinner in the radial direction.

  The plunger 7 is formed with an insertion hole 70 through which the shaft 8 is inserted. The shaft 8 is fixed to the plunger 7 by press-fitting into the insertion hole 70, and moves in the axial direction together with the plunger 7. The shaft 8 is inserted into an insertion hole 620 formed in the main body portion 621 of the core member 62, and a front end portion 81 abuts on an end portion of the spool 3 on the solenoid portion 5 side, and a rear end portion 82 is an inner side of the housing 61. It is arranged inside the cylinder part 613. The plunger 7 is disposed near the rear end 82 in the axial direction of the shaft 8. The outer peripheral surface of the plunger 7 faces the inner peripheral surface of the inner cylindrical portion 613 of the housing 61 and the inner peripheral surface of the annular protrusion 622 of the core member 62.

  Between the plunger 7 and the main body portion 621 of the core member 62, a ring-shaped stopper 71 that is externally fitted to the shaft 8 is disposed. When a current having a rated current value is supplied to the electromagnetic valve 1, the stopper 71 is sandwiched between the plunger 7 and the main body 621 of the core member 62. The plunger 7 is made of a soft magnetic material such as iron, and the shaft 8 and the stopper 71 are made of a nonmagnetic material such as austenitic stainless steel or aluminum.

  The second urging mechanism 9 is a sphere 91 housed in a guide hole 610 formed in the bottom 611 of the housing 61, and a second urging member that urges the sphere 91 to the rear end 82 of the shaft 8. Coil spring 92. The sphere 91 is a substantially spherical and is a spherical member made of a nonmagnetic material such as austenitic stainless steel or aluminum and having a diameter larger than the diameter of the shaft 8. The depth (axial length) of the guide hole 610 is set to such a size that the sphere 91 does not come out even when the shaft 8 is at the moving end (second position described later) when the shaft 8 moves to the spool 3 side. ing.

  FIG. 2 is an enlarged view showing a peripheral portion of the second urging mechanism 9 and the rear end portion 82 of the shaft 8 in FIG. The guide hole 610 has a circular cross section perpendicular to the axial direction along the moving direction of the shaft 8, and is formed at the center of the bottom 611 of the housing 61. The spherical body 91 is movable along the axial direction of the shaft 8 with respect to the housing 61 in the guide hole 610, and the movement in the direction perpendicular to the axial direction of the shaft 8 with respect to the housing 61 is the movement of the guide hole 610. It is regulated by the inner peripheral surface 610a.

  When the sphere 91 moves in the guide hole 610, even if the sphere 91 slides on the inner peripheral surface 610a of the guide hole 610, the sphere 91 is a non-magnetic material. Since the sphere 91 is not attracted to the surface 610a and is a substantially true sphere, the influence of the frictional force generated by sliding with the inner peripheral surface 610a on the slidability of the sphere 91 is limited. Further, since the member interposed between the coil spring 92 and the shaft 8 is the sphere 91, for example, the contact area with the inner peripheral surface 610a is reduced as compared with the case where the member is cylindrical, and the sliding resistance is reduced. Is suppressed.

  A cylindrical boss portion 615 is erected on the bottom surface 610 b of the guide hole 610. The coil spring 92 is fitted into the boss portion 615 and accommodated in the guide hole 610. One end of the coil spring 92 in the axial direction is in contact with the bottom surface 610 b of the guide hole 610, and the other end is in contact with the sphere 91.

  The spring constant of the coil spring 92 is smaller than the spring constant of the coil spring 42 of the first biasing mechanism 4. Thereby, when the exciting current is not supplied to the electromagnetic coil 50, the sphere 91 receives the top of the boss portion 615 by the biasing force of the coil spring 42 of the first biasing mechanism 4 received via the spool 3 and the shaft 8. It abuts on the surface 615a. That is, the sphere 91, the shaft 8, and the spool 3 are in a first position where the sphere 91 is in contact with the top surface 615 a of the boss portion 615 (see FIG. 1A), and the stopper 71 is the plunger 7 and the core member 62. It moves in the axial direction between the second position (see FIG. 1B) sandwiched between the main body 621 and the main body 621.

  As shown in FIG. 2, when the inner diameter of the inner cylindrical portion 613 of the housing 61 is d1, the inner diameter of the annular protrusion 622 of the core member 62 is d2, and the outer diameter of the plunger 7 is d3, d1 and d2 have the same dimensions. , D3 are formed slightly smaller than d1 and d2. Further, assuming that the inner diameter of the guide hole 610 is d4 and the diameter of the sphere 91 is d5, d5 is formed slightly smaller than d4. Furthermore, if the diameter difference between d3 and d1, d2 is Δda (Δda = d1−d3 = d2−d3) and the diameter difference between d4 and d5 is Δdb (Δdb = d4−d5), Δdb is greater than Δda. Is also small. In other words, the radial gap with respect to the housing 61 of the sphere 91 in the direction orthogonal to the axial direction of the shaft 8 is smaller than the radial gap with respect to the housing 61 in the same direction of the plunger 7. In FIG. 2, the difference between d3 and d1 and d2 is exaggerated for clarity of explanation.

  A part of the sphere 91 is accommodated in a recess 820 formed in the rear end portion 82 of the shaft 8. In the present embodiment, the concave portion 820 has a mortar shape, and the inner surface 820a has a tapered shape (conical surface) whose axial depth increases toward the center. In the cross section along the axial direction of the shaft 8, the sphere 91 is in contact with the inner surface 820 a of the recess 820 at two points (contact points 91 a and 91 b) sandwiching the central axis C of the shaft 8. Thereby, the rear end portion 82 side of the shaft 8 is restricted from moving in a direction orthogonal to the axial direction of the shaft 8 with respect to the sphere 91. That is, the shaft 8 is restricted from moving in a direction perpendicular to the axial direction of the plunger 7 with respect to the sphere 91 by accommodating a part of the sphere 91 in the recess 820.

  With the above configuration, the concentricity of the shaft 8 with respect to the housing 61 is enhanced, and the shaft 8 and the plunger 7 can be moved in the axial direction while maintaining the non-contact state between the plunger 7 and the housing 61. Moreover, even when the plunger 7 contacts the housing 61, the contact load becomes small, and the frictional resistance with the housing 61 when the plunger 7 moves in the axial direction is suppressed.

  FIG. 3 is an enlarged view showing the periphery of the tip 81 of the shaft 8 in FIG. The front end portion 81 of the shaft 8 is engaged with the end portion 30 of the spool 3, so that the movement in the direction orthogonal to the axial direction of the spool 3 is restricted.

  In the present embodiment, a recess 300 is formed at the end 30 of the spool 3, and the tip 81 of the shaft 8 is formed in a hemispherical shape. The concave portion 300 has a mortar shape, and the inner surface 300a thereof has a tapered shape in which the axial direction depth increases toward the center portion. In the cross section shown in FIG. 3, the tip portion 81 of the shaft 8 is in contact with the inner surface 300 a of the recess 300 at two points (contact points 81 a and 81 b) sandwiching the central axis C of the shaft 8.

  However, the present invention is not limited to this, and a recess is formed at the tip 81 of the shaft 8, and the protrusion formed at the end 30 of the spool 3 engages with the recess of the tip 81 of the shaft 8. The movement of the portion 81 in the direction (radial direction) perpendicular to the axial direction of the spool 3 may be restricted.

  The gaps between the outer peripheral surfaces of the first land portion 31, the second land portion 32, and the third land portion 34 of the spool 3 and the inner peripheral surface of the valve hole 20 of the sleeve 2 are each port (supply) of the sleeve 2. The dimensions are set to be extremely small so as to prevent leakage of hydraulic oil between the port 21, the output port 22, the discharge port 23, and the feedback port 24). That is, the sleeve 2 and the spool 3 have high concentricity, and the relative movement of the distal end portion 81 of the shaft 8 in the radial direction of the spool 3 is restricted, whereby the sleeve 2 and the spool 3 are inserted into the insertion hole 620 of the core member 62. The inclination of the shaft 8 is suppressed, and the concentricity of the shaft 8 with respect to the housing 61 is enhanced. Thereby, the shaft 8 and the plunger 7 can be moved in the axial direction while maintaining the non-contact state between the shaft 8 and the core member 62. Further, even when the shaft 8 contacts the core member 62, the contact load is reduced, and the frictional resistance with the core member 62 when the shaft 8 moves in the axial direction is suppressed.

  Next, the operation of the electromagnetic valve 1 will be described. When an excitation current is supplied to the electromagnetic coil 50, a magnetic path M through which magnetic flux passes through the housing 61, the core member 62, and the plunger 7 is formed as shown in FIG. An electromagnetic force is generated according to the magnetic flux passing through the magnetic path M formed in this way, and the plunger 7 is attracted to the main body 621 side of the core member 62 by this electromagnetic force, and the shaft 8 presses the spool 3. Since the spool 3 moves in the axial direction toward the plug body 41 against the biasing force of the coil spring 42 of the first biasing mechanism 4, the communication between the supply port 21 and the output port 22 is the second of the spool 3. The output port 22 and the discharge port 23 communicate with each other while being blocked by the land portion 32.

  On the other hand, when the supply of the excitation current to the electromagnetic coil 50 is stopped, the spool 3 moves to the solenoid part 5 side by the biasing force of the coil spring 42 as shown in FIG. 1A, and the supply port 21 and the output port 22 are connected. On the other hand, the communication between the output port 22 and the discharge port 23 is blocked by the third land portion 34 of the spool 3. That is, in the solenoid valve 1, the communication state among the supply port 21, the output port 22, and the discharge port 23 is switched by the axial movement of the spool 3.

  The spool 3 is positioned at a position where the urging force of the coil spring 42 of the first urging mechanism 4 is balanced with the urging force of the coil spring 92 of the second urging mechanism 9 and the electromagnetic force of the electromagnetic coil 50. The For this reason, the axial position in the valve hole 20 can be arbitrarily set by increasing or decreasing the excitation current supplied to the electromagnetic coil 50. As described above, the solenoid valve 1 is configured to change the flow path area of the hydraulic oil between the supply port 21 and the output port 22 and the flow path area between the output port 22 and the discharge port 23. It is possible to adjust the pressure of the hydraulic oil passing through 1.

[Operations and effects of the embodiment]
According to the embodiment described above, the following operations and effects (1) to (6) can be obtained.

(1) Effect of suppressing stick-slip phenomenon and wear Part of the sphere 91 is accommodated in a recess 820 formed in the rear end portion 82 of the shaft 8, and this sphere 91 is attached to the rear end portion 82 of the shaft 8 by a coil spring 92. Since the shaft 8 and the plunger 7 can be moved in the axial direction with respect to the housing 61, the concentricity of the shaft 8 and the plunger 7 with respect to the housing 61 can be enhanced. Thereby, the friction accompanying the axial movement of the shaft 8 and the plunger 7 when moving the spool 3 relative to the sleeve 2 can be suppressed, and the occurrence of stick-slip phenomenon and wear can be suppressed.

(2) Effect of suppressing hysteresis The frictional resistance when the shaft 8 and the plunger 7 move in the axial direction is reduced, so that the shaft 8 and the plunger 7 are moved from the first position shown in FIG. 1A to FIG. 1B. The axial position of the spool 3 relative to the sleeve 2 with respect to the excitation current when moving toward the second position shown, and the spool 3 against the excitation current when moving from the second position toward the first position. It is also possible to suppress hysteresis, which is a difference from the position in the axial direction relative to the sleeve 2. That is, the frictional force generated between the shaft 8 and the plunger 7 and the housing 61 and the core member 62 moves from the first position toward the second position and from the second position to the first position. In this embodiment, this frictional force is reduced, and this frictional force is reduced, so that the hysteresis can be suppressed and the excitation current can be adjusted. Thus, it is possible to accurately control the pressure of the hydraulic oil supplied from the output port 22 of the sleeve 2 to the target device.

(3) Effect of suppressing inclination of shaft 8 with respect to housing 61 As tip 81 of shaft 8 engages with end 30 of spool 3, relative movement of tip 81 of shaft 8 in the radial direction of spool 3 is achieved. Since it is regulated, the inclination of the shaft 8 with respect to the housing 61 can be suppressed, and the concentricity of the shaft 8 and the plunger 7 with respect to the housing 61 can be improved more reliably.

(4) Effect of suppressing radial movement of shaft 8 with respect to spool 3 and sphere 91 In shaft 8, tip 81 comes into contact with inner surface 300 a of recess 300 at two points in the cross section along the axial direction, and rear end Since the sphere 91 comes into contact with the inner surface 820a of the recess 820 formed in 82 at two points, the radial movement with respect to the spool 3 and the sphere 91 is reliably restricted.

(5) Effect of suppressing uneven wear of the sphere 91 Since the sphere 91 can be rotated by friction with the inner surface 300a of the concave portion 300 of the spool 3, for example, only a specific part on the surface does not slide with the inner surface 300a. It is suppressed that the spherical body 91 wears unevenly.

(6) Suppression effect of spool 3 When hydraulic oil discharged from an oil pump such as a gear pump or vane pump is supplied to the supply port 21, the supply pressure slightly pulsates. If the spool 3 slightly vibrates in the axial direction with respect to the sleeve 2 due to the pulsation of the supply pressure, the inner peripheral surface of the valve hole 20 may be worn. However, in the present embodiment, since the fine vibrations of the spool 3 and the shaft 8 are suppressed by the coil spring 92 of the second urging mechanism 9, adverse effects due to the fine vibration of the spool 3 can be suppressed. Further, when an excitation current whose current amount is adjusted by, for example, PWM control is supplied to the electromagnetic coil 50, a slight vibration in the axial direction may occur in the spool 3 due to the harmonic component of the excitation current. The suppression effect by the coil spring 92 is exhibited also about vibration.

[Modification 1 of Embodiment]
Next, Modification 1 of the embodiment of the present invention will be described with reference to FIG.

  FIG. 4 is an enlarged cross-sectional view of a part of the shaft 8 according to the first modification of the embodiment. In FIG. 4, the rear end portion 82 of the shaft 8 is shown in a cross section along the axial direction including the central axis C, and the sphere 91 in contact with the rear end portion 82 is indicated by a virtual line (two-dot chain line).

  In this modification, the shape of the recess 820 of the shaft 8 in the above embodiment is modified. That is, in the above embodiment, the case where the concave portion 820 has a mortar shape and the inner surface 820a has a tapered shape formed of a conical surface has been described, but in the first modification, the concave portion 820 has a mortar shape as described above. However, the inner surface of the recess 820 in the cross section along the axial direction of the shaft 8 is formed by a combination of a pair of arcs.

  More specifically, in the cross section along the axial direction of the shaft 8, the inner surface of the recess 820 includes first and second curves 820 b and 820 c having a concave arc shape having a radius of curvature larger than the radius of the sphere 91, These first and second curves 820 b and 820 c intersect at the central axis C of the shaft 8. In this cross section, the sphere 91 is in contact with the first curve 820b at the contact point 91a and is in contact with the second curve 820c at the contact point 91b.

  According to this modification, the same operation and effect as the above embodiment can be obtained. In addition, since the inner surface of the recess 820 has a concave arc shape, for example, even when the electromagnetic valve 1 receives strong vibrations, it is possible to more reliably suppress the sphere 91 from being misaligned with respect to the shaft 8. .

[Modification 2 of Embodiment]
Next, a second modification of the embodiment of the present invention will be described with reference to FIG.

  FIG. 5 is an enlarged cross-sectional view of a part of the solenoid valve according to the second modification of the embodiment. In FIG. 5, similarly to FIG. 4, the rear end portion 82 of the shaft 8 is shown in a cross section along the axial direction including the central axis C, and the sphere 91 in contact with the rear end portion 82 is indicated by a virtual line (two-dot chain line). Show.

  This modification is a modification of the shape of the recess 820 of the shaft 8 in the above embodiment, and the inner surface of the recess 820 is formed in a concave spherical shape having a radius of curvature larger than the radius of the sphere 91. The sphere 91 is in contact with the innermost part 820d corresponding to the center of the recess 820.

  Also by this modification, the same operation and effect as the above-mentioned embodiment can be obtained. Further, the recess 820 can be easily processed.

(Appendix)
As mentioned above, although this invention was demonstrated based on embodiment and its modification 1, 2, the embodiment described above and the modification 1, 2 do not limit the invention based on a claim. In addition, it should be noted that not all the combinations of features described in the embodiments are essential to the means for solving the problems of the invention. Further, the present invention can be appropriately modified and implemented without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Solenoid valve 2 ... Sleeve 20 ... Valve hole 21 ... Supply port 22 ... Output port 3 ... Spool 42 ... Coil spring (1st biasing member) 5 ... Solenoid part 50 ... Electromagnetic coil 51 ... Holding member 61 ... Housing 62 ... Core member 7 ... Plunger 8 ... Shaft 81 ... Front end part 82 ... Rear end part 91 ... Spherical body 92 ... Coil spring (second biasing member)

Claims (4)

A cylindrical sleeve having a plurality of ports through which hydraulic oil flows; and
A spool that is accommodated in a valve hole formed in the sleeve so as to be axially movable, and that changes a flow passage area between the ports by the axial movement;
A solenoid unit that operates upon receiving an excitation current and presses the spool to one side in the axial direction with a pressing force according to the magnitude of the excitation current;
A first urging member that urges the spool toward the solenoid part side,
The solenoid part is
An electromagnetic coil for generating magnetic flux by the exciting current;
A housing fixed to the sleeve and serving as a magnetic path of the magnetic flux;
A core member housed in the housing;
A cylindrical plunger that is attracted to the core member that has received the magnetic flux and moves in an axial direction with respect to the housing;
A shaft whose tip is in contact with the spool and moves axially integrally with the plunger;
A sphere movable along the axial direction of the plunger with respect to the housing;
A second biasing member that biases the spherical body toward the rear end of the shaft;
The sphere is restricted from moving in a direction perpendicular to the axial direction of the plunger with respect to the housing,
The shaft is restricted from moving in a direction perpendicular to the axial direction of the plunger with respect to the sphere by accommodating a part of the sphere in a recess formed at a rear end thereof.
solenoid valve. The concave portion of the shaft has a mortar shape on the inner surface,
The sphere is in contact with the inner surface of the recess at two points sandwiching the central axis of the shaft in a cross section along the axial direction of the shaft.
The solenoid valve according to claim 1. The concave portion of the shaft has a concave spherical shape whose inner surface has a radius of curvature larger than the radius of the sphere.
The solenoid valve according to claim 1. The tip of the shaft is restricted from moving in a direction perpendicular to the axial direction of the spool by engaging the end of the spool.
The solenoid valve according to any one of claims 1 to 3.

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