WO2011021730A1

WO2011021730A1 - Solenoid valve

Info

Publication number: WO2011021730A1
Application number: PCT/KR2009/004594
Authority: WO
Inventors: Chang Hoon Lee; Eui Dong Roh; Do Hyung Kim; Ki Ryong Lee; Chan Shik Ahn; Young Keun Kim
Original assignee: Unick Corporation
Priority date: 2009-08-17
Filing date: 2009-08-17
Publication date: 2011-02-24

Abstract

Disclosed is a solenoid valve for controlling a high flow rate for direct shift control of an automatic transmission. The solenoid valve includes a holder (110) having inlet and outlet ports (111,112), a residual pressure relief-discharge port (113) and a passageway (114), a spool (120) located in the passageway (114) of the holder (110), a rod (130) closely contacting the spool (120), a plunger (140) surrounding the rod (130), a bobbin (150) surrounding the plunger (140) and having a coil (151 ), a yoke (160) between the bobbin (150) and the holder (110), a core (170), and a case (180). The valve removes resistance to fluid discharge from a chamber (171 ) during plunger movement to enhance responsiveness of a controlled pressure, and allows a fluid to flow into a plunger actuator, thereby suppressing a temperature increase by the coil (151 ) while ensuring a damping function in the plunger actuator.

Description

SOLENOID VALVE

The present invention relates to a solenoid valve for direct shift control of an automatic transmission. More particularly, the present invention relates to a proportional solenoid valve for controlling a high flow rate for direct shift control of an automatic transmission, which removes resistance to fluid discharge from a chamber defined in a core during plunger movement to enhance responsiveness of a controlled pressure, and allows some of a fluid used for shift control to flow into a plunger actuator in order to suppress a temperature increase by a coil and to ensure a damping function in the plunger actuator.

Generally, a proportional solenoid valve for controlling a high flow rate for direct shift control of an automatic transmission employs a spool, which can minimize a force for operating a plunger. Further, the proportional solenoid valve performs feedback of a controlled pressure to an upper end or a lower end of the spool, so that a gap between the rod and a plunger actuator controlling the spool with a solenoid can be reduced.

Fig. 1 is a configuration view of a conventional proportional solenoid valve employing such a spool. For easy understanding of operation of the solenoid valve, the left side with reference to a dotted centreline of Fig. 1 shows that a space between an inlet port 28 and an outlet port 30 is closed by a spool 15, and the right side shows that the space between the inlet port 28 and the outlet port 30 is opened by the spool 15.

Referring to Fig. 1, the conventional proportional solenoid valve includes: a holder 16 which has the inlet and

outlet ports

28, 30 for guiding a fluid flow and a residual pressure reliefdischarge port 31; the spool 15 disposed in a passageway 29 of the holder 16; a rod 19 closely contacting a lower end of the spool 15; a plunger 20 assembled to the rod 19; a bobbin 33 surrounding the plunger 20 and having a coil 35 wound around the bobbin 33; a yoke 17 located between an upper side of the bobbin 33 and a lower side of the holder 16; a core 23 having an outer flange closely contacting a lower side of the bobbin 33 and being disposed at a middle part thereof on a lower surface of the plunger 20; a spring 36 located between a hollow space 21 of the core 23 and an inner surface of the rod 19; and a case 24 surrounding a lower surface of the core 23, i.e. an outer periphery of the coil 35, and the lower side of the holder 16.

The spool 15 has a fourstepped cylindrical shape which enables control of passageway areas of the inlet port 28 and the residual pressure reliefdischarge port 31 inside the holder 16, and is located on the rod 19 such that the lower end of the spool 15 closely contacts an upper surface of the rod 19 moved by the plunger 20.

The holder 16 is formed with a feedback pressure introduction port 26 communicating with a feedback channel 14 such that a controlled pressure discharged through the outlet port 30 connected to an external channel can be fed back to an upper side of the spool 15. Further, the holder 16 is formed with a feedback pressure eliminating port 25 which blocks the feedback pressure introduced through the feedback pressure introduction port 26 from being applied to the upper side of the spool 15. Further, a damper screw 42 is fastened to an upper portion of the holder 16 and a damper spring 40 is provided between the damper screw 42 and the holder 16.

The rod 19 is inserted into a middle part of the plunger 20 and is seated on an upper portion of the damper spring 36. The rod 19 is formed at an upper portion thereof with a viahole 18, which is perpendicular to an axial direction of the solenoid valve, to ensure smooth communication of the closed pressure during updown reciprocation of the plunger.

Further,

cylindrical bushings

32, 22 are pressfitted into a space between the yoke 17 and the rod 19 and into a space between the core 23 and the rod 19 to allow the plunger 20 to be operated without horizontal and slanted movement, respectively. Here, a Teflon coating is formed on inner surfaces of the

cylindrical bushings

32, 22 to prevent friction between the

bushings

32, 22 and the rod 19.

A guide member 43 is interposed between an outer circumference of the plunger 20, the core 23 and the yoke 17, which surround the outer circumference of the plunger 20, to efficiently enhance a magnetic fieldflow by suppressing vibration of the plunger 20 and minimizing a gap between the core 23 and the yoke 17, whereby a reduction in amplitude of an output pressure can be obtained through an increase in vibration and magnetic field during operation of the plunger 20. An injectionmolded connector 41 is fitted into a lower surface of the case 24.

The proportional solenoid valve of this configuration is provided to a valve body of an automatic transmission and is used to control a fluid flow. That is, the proportional solenoid valve controls the fluid flow in such a way that, when power is not applied to the coil 35, the spool 15 opens the passageway between the inlet port 28 and the outlet port 30 by operation of the spring 40 on the upper end of the spool 15 and the spring 36 on the lower end of the rod 19, as shown in the crosssection of the right side of Fig. 1, and when power is applied to the coil 35, the plunger 20, rod 19 and spool 15 are moved to close the passageway between the inlet port 28 and the outlet port 30 by the magnetic force generated from the coil 35, as shown in the crosssection of the left side of Fig. 1.

If the proportional solenoid valve is installed in a wet installation condition where the proportional solenoid valve is completely immersed in an Automatic Transmission Fluid (ATF), the ATF provides a function of suppressing a temperature increase caused by heat generated from the coil during operation of the solenoid valve, and a damping function in operation of the plunger 20 by flowing into an actuator of the plunger 20 through a gap between the bobbin 33 and the yoke 17 or between the rod 19 and the yoke 17. Here, the viahole 18 formed in the rod 19 serves to allow the closed pressure to efficiently communicate between the upper and lower portions of the plunger 20 during updown reciprocation of the plunger 20.

In this wet installation condition, however, when the temperature of the oil is decreased to a very low temperature due to surrounding temperatures, the viscosity of the oil in the actuator of the plunger 20 is increased , which causes nonsmooth flow of the oil through the viahole 18. Particularly, when the plunger 20 is lowered, oil discharge from a chamber 37 defined between the lower portion of the rod 19 and the core 23 undergoes resistance, thereby influencing responsiveness of the controlled pressure.

If the proportional solenoid valve is installed in a dry installation condition where the proportional solenoid valve is partially or not immersed in the automatic transmission fluid, no fluid is supplied into the actuator of the plunger 20 and only air is present therein. As a result, the function of suppressing the temperature increase of the coil 35 and the damping function in the actuator of the plunger 20 cannot be obtained, thereby causing ripples in amplitude of an output pressure during the operation of the plunger and failing to suppress the temperature increase in the coil due to an increase in temperature of the surrounding ATF.

The present invention is conceived to solve the above and other problems of the related art, and an aspect of the present invention is to provide a proportional solenoid valve that allows an oil in a chamber, which is defined between a lower portion of a rod and a core, to be rapidly discharged from the core during downward movement of a plunger to remove resistance to fluid discharge from the chamber, thereby enhancing responsiveness of a pressure control.

Another aspect of the present invention is to provide a proportional solenoid valve that allows a fluid in a holder to flow into a plunger actuator in the case of a dry installation condition where oil is not supplied into the plunger actuator, thereby suppressing a temperature increase of a coil while ensuring a damping function in the plunger actuator.

In accordance with one embodiment of the present invention, the above and other aspects of the present invention can be accomplished by the provision of a proportional solenoid valve for controlling a high flow rate for direct shift control of an automatic transmission, which includes: a holder which has inlet and outlet ports guiding a fluid flow, a residual pressure reliefdischarge port and a passageway formed therein; a spool located in the passageway of the holder; a rod closely contacting a lower end of the spool; a plunger assembled to surround the rod; a bobbin assembled to surround the plunger and having a coil wound around the bobbin; a yoke disposed between the bobbin and the holder; a core inserted into a lower end of the bobbin to be located under the plunger; and a case surrounding lower portions of the core and the holder.

A chamber and a discharge channel may be formed between the rod and the core, in which the discharge channel rapidly discharges an oil from the chamber to remove resistance to fluid discharge from the chamber. The discharge channel is connected to an outside of the valve and the coil.

Further, the valve may further include a channel through which a fluid filled in the passageway of the holder flows into an actuator of the plunger.

According to one embodiment of the present invention, the proportional solenoid valve allows an oil in the chamber defined between a lower portion of the rod and the core to be rapidly discharged from the core through the discharge channel connected to the outside of the core during downward movement of a plunger, thereby removing resistance to fluid discharge from the chamber. As a result, the proportional solenoid valve has enhanced response of a controlled pressure during operation of the plunger.

Further, according to another embodiment of the present invention, even in a dry installation condition where a fluid is not supplied into a plunger actuator, the proportional solenoid valve allows some of a fluid in the passageway to flow into the plunger actuator through a channel while being discharged through the residual pressure reliefdischarge port of the holder during downward movement of the plunger and the spool, thereby preventing a temperature increase in the coil and ensuring a damping function of a plunger actuator. Therefore, it is possible to prevent ripples in amplitude of an output pressure during operation of the plunger.

The above and other aspects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a crosssectional view of a conventional proportional solenoid valve for controlling a high flow rate for direct shift control of an automatic transmission;

Fig. 2 is a crosssectional view of a proportional solenoid valve for controlling a high flow rate for direct shift control of an automatic transmission, according to one embodiment of the present invention; and

Figs. 3 and 4 are enlarged views of main parts of the proportional solenoid valve shown in Fig. 2.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In description of the embodiments of the present invention, details of wellknown structures and functions apparent to a person having ordinary knowledge in the art will be omitted herein for clarity of description. Furthermore, like components will be denoted by like reference numerals throughout the drawings.

Fig. 2 is a crosssectional view of a proportional solenoid valve for controlling a high flow rate for direct shift control of an automatic transmission, according to one embodiment of the present invention, and Figs. 3 and 4 are enlarged views of main parts of the proportional solenoid valve shown in Fig. 2.

Referring to Fig. 2, the proportional solenoid valve according to the embodiment includes: a holder 110 which has inlet and

outlet ports

111, 112 guiding a fluid flow, a residual pressure reliefdischarge port 113 and a passageway 114 formed therein; a spool 120 located in the passageway 114 of the holder 110; a rod 130 closely contacting a lower end of the spool 120; a plunger 140 assembled to surround the rod 130; a bobbin 150 assembled to surround the plunger 140 and having a coil 151 wound around the bobbin 150; a yoke 160 disposed between the bobbin 150 and the holder 110; a core 170 inserted into a lower end of the bobbin 150 to be located under the plunger 140; a case 180 surrounding lower portions of the core 170 and the holder 110; and a connector 190 for supplying power to the solenoid valve.

Next, main features of the proportional solenoid valve according to this embodiment of the invention will be described with reference to Figs. 3 and 4.

Referring to Fig. 3, a chamber 171 and a discharge channel 172 are formed between the rod 130 and the core 170. Here, the discharge channel 172 rapidly discharges an oil from the chamber 171 to remove resistance to fluid discharge from the chamber 171. Further, a reflux channel 173 is formed around the core 170 and connected to the discharge channel 172. The reflux channel 173 is also connected to an outside of the valve and the coil 151. A gap 174 is defined between an outer circumference of a lower portion of the bobbin 150 and the case 180, and is connected to the reflux channel 173 through a transfer channel 175.

Therefore, during downward movement of the plunger 140, an oil in the chamber 171 defined between the lower portion of the rod 130 and the core 170 can be rapidly discharged from the core 170 through the discharge channel 172 and reflux channel 173, so that resistance to fluid discharge from the chamber 171 can be removed.

Furthermore, the oil in the chamber 171 defined between the lower portion of the rod 130 and the core 170 is transferred to the coil 151 through the discharge channel 172, reflux channel 173, transfer channel 175 and gap 174 during the downward movement of the plunger 140 to provide a function of suppressing a temperature increase by the coil 151 and a damping function in the actuator of the plunger 140, thereby preventing ripples in amplitude of an output pressure during operation of the plunger 140 even in a dry installation condition where an oil is not supplied to the valve.

The connector 190 has a coupling protrusion 191 extending through an upper surface thereof and the case 180 is formed at a lower end thereof with a coupling groove 181 corresponding to the coupling protrusion 191, so that the connector 190 can be easily attached to or detached from the case 180.

Here, there can be given an assembly tolerance in the solenoid valve, more specifically, between the case 180 and the connector 190 to ensure efficient assembly therebetween. As a result, foreign matter can be introduced into the solenoid valve through the tolerance. According to this embodiment, however, when the solenoid valve is operated to magnetize the core 170, the foreign matter is attached to the surface of the case 180 and removed by the fluid discharged through the reflux channel 173 during downward movement of the plunger 140.

Referring to Fig. 4, the solenoid valve further includes

channels

110b, 110c through which the fluid in the passageway 114 of the holder 110 can flow into the actuator of the plunger 140. The

channels

110b, 110c constitute a space 110a, which communicates with a gap “a” between the rod 130 and the yoke 160, at a portion where the spool 120 adjoins the rod 130, and comprise a first channel 110b and a second channel 110c defined at a lower portion of the holder 110 such that the passageway 114 communicates with the space 110a through the first and

second channels

110b, 110c.

In this embodiment, the space 110a is illustrated as being formed between a lower surface 121 of the spool 120 and an upper surface 161 of the yoke 160 by machining the lower surface 121 of the spool 120. However, it should be noted that the present invention is not limited to this configuration. Alternatively, the space 110a may be formed between the lower surface 121 of the spool 120 and the upper surface 161 of the yoke 160 by machining the upper surface 161 of the yoke 160.

The first and

second channels

110b, 110c are formed on coupling surfaces of the holder 110 and the yoke 160. The first channel 110b is formed by cutting a portion of a coupling circumferential surface 115 of the holder 110 in the axial direction so as to communicate at one end thereof with the passage way 114. The second channel 110c is formed by cutting a portion of a coupling end surface 116 of the holder 110 in the horizontal direction.

Next, operation of the proportional solenoid valve according to this embodiment will be described. First, if the proportional solenoid valve is installed in a wet installation condition where the proportional solenoid valve is completely immersed in an Automatic Transmission Fluid (ATF), the ATF provides a function of suppressing a temperature increase caused by heat generated from the coil 151 during operation of the solenoid valve, and a damping function in operation of the plunger 140 by flowing into the actuator of the plunger 140 through a gap between the bobbin 150 and the yoke 160 or between the rod 130 and the yoke 160. Further, a viahole 131 formed in the rod 130 serves to allow the closed pressure to efficiently communicate between upper and lower portions of the plunger 140 during updown reciprocation of the plunger 140.

In this case, since the fluid in the chamber 171 defined between the lower portion of the rod 130 and the core 170 is rapidly discharged from the core 170 through the discharge channel 172, so that resistance to fluid discharge from the chamber 171 can be removed. Additionally, when the oil in the actuator of the plunger 140 has a very low temperature and is increased in viscosity due to surrounding temperatures, the solenoid valve of this embodiment ensures smooth flow of the oil in the actuator of the plunger 140 so as not to provide any influence on responsiveness of the controlled pressure during the updown reciprocation of the plunger 140, thereby enhancing the responsiveness of the controlled pressure.

Further, the oil discharged through the viahole 172 of the core 170 is introduced into the reflux channel 173 on the outer circumferential surface of the core 170 and flows to the connector 190 through a fine gap between the core 170 and the bobbin 150. Here, the reflux channel 173 allows the oil discharged through the discharge channel 172 to be received on the outer circumferential surface of the core 170, so that the oil can be rapidly discharged from the chamber 171.

In Fig. 4, according to this embodiment of the invention, when the spool 120 is raised to connect the inlet port 111 and the outlet port 112, the passageway 114 and the first channel 110b are closed by the spool 120, and, when the spool 120 is lowered to close the connection between the inlet port 111 and the outlet port 112, the passageway 114 and the first channel 110b are opened so that some of the fluid flows into the actuator of the plunger 140 through the first channel 110b, the second channel 110c, the space 110a, the gap “a” between the rod 130 and the yoke 160, and a fine gap between the rod 130 and a bushing 162, while the fluid is discharged through the residual pressure reliefdischarge port 113.

Accordingly, even in the case where only air is present in the actuator of the plunger 140 due to no supply of a fluid into the actuator of the plunger 140 in a dry installation condition where the proportional solenoid valve is partially or not immersed in the automatic transmission fluid, the oil flows into the actuator of the plunger 140 and serves to suppress the temperature increase of the coil 151 and provides the damping function to the actuator of the plunger 140, thereby preventing ripples in amplitude of an output pressure during operation of the plunger 140 while preventing the temperature increase of the coil caused by the surrounding automatic transmission fluid.

Although some embodiments have been provided to illustrate the present invention, it should be noted that the embodiments are given by way of illustration only and do not limit the scope of the present invention, and it will be apparent to those skilled in the art that various modifications, changes, and substitutions can be made without departing from the spirit and scope of the present invention. Therefore, the scope and sprit of the present invention should be interpreted only by the following claims and equivalents thereof.

Claims

A solenoid valve, comprising:

a holder 110 which has inlet and outlet ports 111, 112 guiding a fluid flow, a residual pressure relief-discharge port 113 and a passageway 114 formed therein;

a spool 120 located in the passageway 114 of the holder 110;

a rod 130 closely contacting a lower end of the spool 120;

a plunger 140 assembled to surround the rod 130;

a bobbin 150 assembled to surround the plunger 140 and having a coil 151 wound around the bobbin 150;

a yoke 160 disposed between the bobbin 150 and the holder 110;

a core 170 inserted into a lower end of the bobbin 150 to be located under the plunger 140; and

a case 180 surrounding lower portions of the core 170 and the holder 110,

wherein a chamber 171 and a discharge channel 172 are formed between the rod 130 and the core 170, the discharge channel 172 rapidly discharging an oil from the chamber 171 to remove resistance to fluid discharge from the chamber 171 and being connected to an outside of the solenoid valve and the coil 151,

a reflux channel 173 is formed around the core 170 and connected to the discharge channel 172, the reflux channel 173 being connected to the outside of the solenoid valve and the coil 151, and

a gap 174 is defined between an outer circumference of a lower portion of the bobbin 150 and the case 180, and is connected to the reflux channel 173 through a transfer channel 175.
The solenoid valve according to claim 1, further comprising:

a connector 190 for supplying power to the solenoid valve,

wherein the connector 190 has a coupling protrusion 191 extending through an upper surface thereof, and the case 180 is formed at a lower end thereof with a coupling groove 181 corresponding to the coupling protrusion 191.
The solenoid valve according to claim 2, further comprising:

channels 110b, 110c allowing a fluid filling the passageway 114 of the holder 110 to flow into an actuator of the plunger 140.