WO2012153893A1

WO2012153893A1 - Pressure control valve

Info

Publication number: WO2012153893A1
Application number: PCT/KR2011/006093
Authority: WO
Inventors: Chang-Hoon Lee; Eui-Dong Roh; Chan-Shik AHN; Sun-Jong RYU
Original assignee: Unick Corporation
Priority date: 2011-05-11
Filing date: 2011-08-18
Publication date: 2012-11-15
Also published as: KR101123016B1; CN103502697B; CN103502697A

Abstract

Disclosed is a pressure control valve used in a clutch of an automatic transmission. The pressure control valve includes a valve body having a supply port, a control port and a discharge port therein; a first insert disposed inside the valve body, the first insert being formed with an inlet connected to the supply port and an outlet for discharging fluid supplied through the inlet; a ball disposed inside the first insert to open/close the outlet; a second insert coupled to the outlet side of the first insert, the second insert being formed with a first discharge hole connected to the control port and a second discharge hole connected to the discharge port; a rod movably provided to the valve body, the rod having one end extending toward the ball, the rod having a poppet formed in the middle thereof to open/close the second discharge hole; and a solenoid moving the rod.

Description

PRESSURE CONTROL VALVE

The present invention relates to a pressure control valve used in a clutch of an automatic transmission, and more specifically, to a proportional control valve for controlling pressure of fluid according to current.

In general, a transmission is a gearing apparatus for converting power generated by an engine into a desired rotational force according to speed and transmitting the same. Such transmissions are classified into manual transmissions in which gear shifting is manually performed by a driver and automatic transmissions in which gear shifting is automatically performed according to a certain pattern.

The automatic transmission includes a torque converter, an operation mechanism, a planetary gear, a multi-plate clutch, a hydraulic control mechanism, and an electrical controller. In particular, the multi-plate clutch includes a clutch retainer, a plurality of clutch plates coupled to the clutch retainer, a plurality of clutch discs coupled to a clutch hub and disposed between the plurality of clutch plates and a clutch cylinder installed between the clutch plates and the clutch retainer. The multi-plate clutch urges the clutch plates against the clutch discs to transmit power thereto when hydraulic pressure is applied to the clutch cylinder.

The hydraulic control mechanism includes a pressure control valve. Pressure control valves are classified into a spool type, a ball type, a poppet type, and the like according to internal configurations thereof. In the spool type pressure control valve, supply pressure supplied from a conventional oil pump is suitably controlled by a spool, whereby pressure control can be obtained. Here, since one or more signal pressures from a corresponding valve according to a shift stage are applied to specific ports in the spool type pressure control valve, the pressures controlled by the pressure control valve can be controlled by the same number as the number of ports to which the signal pressures are applied.

However, since the control pressure controlled by the spool is set to be large in consideration of the maximum load pressure required in a corresponding frictional element of a planetary gear when shifting, if maximum load pressure is not required, the control pressure functions as surplus pressure when shifting. Thus, this causes unnecessary loss in consideration of the efficiency in driving force of an engine.

Such a problem also occurs in a ball type or poppet type pressure control valve. Particularly, since a ball or poppet type pressure control valve is generally of a two-way type, when the control pressure is zero, the fluid supplied from an oil pump is completely discharged, increasing a consumption flow rate. Accordingly, this functions as an unnecessary loss in consideration of the efficiency in driving force of an engine. In addition, since a two-way type pressure control valve should be provided with an additional orifice at an inflow hole through which fluid is supplied, there are disadvantages in that the configuration is complicated and manufacture thereof is not easy.

The present invention is conceived to solve the problems of the related art, and an aspect of the present invention is to provide a pressure control valve capable of effectively controlling pressure of fluid and preventing unnecessary waste of fluid.

Another aspect of the present invention is to provide a pressure control valve capable of improving assemblability and operability by securing coaxiality and reducing manufacturing costs and improving operational reliability by minimizing the number of components.

In accordance with an aspect of the present invention, a pressure control valve includes: a valve body having a supply port, a control port and a discharge port formed therein; a first insert disposed inside the valve body, the first insert being formed with an inlet connected to the supply port and an outlet for discharging fluid supplied through the inlet; a ball disposed inside the first insert to open/close the outlet; a second insert coupled to the outlet side of the first insert, the second insert being formed with a first discharge hole connected to the control port and a second discharge hole connected to the discharge port; a rod movably provided to the valve body, the rod having one end extending toward the ball, the rod having a poppet formed in the middle thereof to open/close the second discharge hole; and a solenoid moving the rod.

Here, the solenoid may include a bobbin having a coil wound around an outer periphery thereof; a core integrally formed with the valve body to be inserted through one end of the bobbin, the core having a through-hole to which the rod is coupled; and a plunger installed to the other end of the rod and positioned within the bobbin.

According to embodiments of the invention, the outlet of the first insert and the second discharge hole of the second insert are opened/closed or the opening amounts thereof are controlled using the ball and the poppet according to current applied to the solenoid, whereby it is possible to effectively control the pressure of the fluid discharged to the control port and prevent unnecessary waste of fluid.

In addition, the bobbin of the solenoid is integrally formed with the valve body and the single rod is provided. Thus, it is possible to improve the assemblability and operability by securing coaxiality. Further, it is possible to reduce costs and improve operational reliability by minimizing the number of components.

Fig. 1 is a perspective view of a pressure control valve according to one exemplary embodiment of the present invention;

Figs. 2 and 3 are longitudinal and transverse sectional views of the pressure control valve according to this embodiment, respectively;

Fig. 4 is a longitudinal sectional view of a valve of the pressure control valve according to this embodiment, as viewed from another direction;

Fig. 5 is an enlarged view of a portion of a solenoid of the pressure control valve according to the embodiment; and

Figs. 6 to 8 show operational states of the pressure control valve according to the embodiment.

[Reference Numerals for Major Elements in Drawings]

100: Valve 110: Valve Body

112: Flange 114: Core

116a: Supply Port 116b: Control Port

116c: Discharge Port 118a: Mounting Space

118b: Through-Hole 120: First Insert

122: Body 122a: Inlet

122b: Outlet 124: Cover

126: Operational Space 126a: Guide Protrusion

126b: Guide Groove 130: Ball

140: Second Insert 142: First Discharge Hole

144: Second Discharge Hole 150: Rod

152: Poppet 154: Caulking Groove

162: Band Type Filter 164: Thin Plate Type Filter

166: O-Ring 200: Solenoid

210: Coil 220: Bobbin

230: Plunger 240: Case

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 and assignment of reference numerals to elements shown in the drawings, like elements will be denoted by like reference numerals throughout the specification and the drawings.

Fig. 1 is a perspective view of a pressure control valve according to an exemplary embodiment of the present invention.

Referring to Fig. 1, a pressure control valve according to this embodiment includes a valve 100 which applies a control pressure to fluid supplied from the outside to supply the fluid to a clutch side, and a solenoid 200 which controls the opening amount of the valve 100 according to current applied from the outside to control the control pressure.

Referring to Figs. 2 to 6, the internal configuration of the valve 100 and the solenoid 200 will be described in more detail.

Figs. 2 and 3 are longitudinal and transverse sectional views of the pressure control valve according to this embodiment, respectively, and Fig. 4 is a longitudinal sectional view of a valve of the pressure control valve according to this embodiment, as viewed from another direction.

The valve 100 includes a valve body 110, a first insert 120 disposed inside the valve body 110, a ball 130 disposed inside the first insert 120, a second insert 140 coupled to a lower end of the first insert 120, and a rod 150 movably disposed inside the valve body 110.

The valve body 110 is formed in the shape of a multi-stage spool. The valve body 110 is formed at a lower end thereof with a flange 112 to be coupled to the solenoid 200, and a core 114 extends from a lower side of the flange 112 and is inserted into a bobbin 220 of the solenoid 200. The valve body 110 has supply ports 116a formed in the middle thereof to supply fluid, a control port 116b formed at an upper end thereof to discharge the fluid controlled at predetermined pressure, and a discharge port 116c formed at a lower end thereof to discharge the fluid for removing the remaining pressure. The valve body 110 has a mounting space 118a which receives the first and

second inserts

120, 140 therein, and the core 114 is formed with a through-hole 118b, into which the rod 150 is movably inserted.

Here, the supply ports 116a are equipped with a band type filter 162 for filtering foreign matter introduced together with fluid, and the control port 116b is equipped with a thin plate type filter 164 for filtering foreign matter contained in the fluid supplied toward a clutch (not shown). Further, an O-ring 166 is installed around an outer periphery of an upper portion of the valve body 110 for sealing the valve body 110 when the pressure control valve is installed.

As such, since the valve body 110 is integrally formed with the core 114, it is possible to minimize the number of components, making it possible to reduce costs while improving assemblability and operational reliability. In addition, it is possible to secure the coaxiality of a rod 150 with the valve body 110 and the core 114, in which the rod 150 is positioned, thereby improving operability.

The first insert 120 serves to control discharge and discharge pressure of fluid supplied through the supply ports 116a, together with the ball 130 disposed therein. The first insert 120 includes a body 122 open at an upper end thereof, and a cover 124 which seals the open upper end of the body 122.

The body 122 of the first insert 120 is formed in the shape of a cup having an operation space 126 formed therein. Inlets 122a connected to the supply ports 116a are formed on a side of the body 122, and an outlet 122b for discharging the fluid supplied through the inlets 122a is formed on a lower end of the body 122. In addition, an inner wall of the operation space 126, more specifically, a portion of the inner wall lower than the inlets 122a is formed with a guide protrusion 126a for guiding the movement of the ball 130 and a guide groove 126b for guiding the discharge of fluid. A plurality of guide protrusions 126a and guide grooves 126b may be radially disposed along the inner wall of the operation space 126, as shown in Fig. 3.

The cover 124 of the first insert 120 has a disc shape capable of sealing the open upper end of the body 122. A protrusion 124a is formed on a lower surface of the cover 124 and protrudes toward the operation space 126. The protrusion 124a serves to prevent the inlets 122a from being closed by the ball 130 by constraining movement of the ball 130 disposed inside the first insert 120.

The first insert 120 is formed in the same cylindrical shape as the mounting space 118a of the valve body 110, wherein some portions of an outer periphery of the first insert 120 are formed as planes, as shown in Fig. 3. That is, portions of the outer periphery of the first insert 120 having the inlets 122a formed therein are in close contact with an inner wall of the valve body 110 of the valve body 110 and the plane portions of the first insert are spaced apart from the inner wall of the valve body 110. The reason why the portions of the outer periphery of the first insert 120 are formed as planes is to form transfer paths 128 between the valve body 110 and the first insert 120 so that the fluid discharged through first discharge holes 142 of the second insert 140 can be transferred to the control port 116b of the valve body 110 (see Fig. 4).

In such configuration of the first insert 120, since the fluid discharged through the first discharge holes 142 is transferred along the transfer paths 128, each having a semi-circular cross section, internal spaces of the first discharge holes 142 and internal spaces of the transfer paths 128 function as a damper of the fluid. Thus, pressure shot does not occur during applied current, so that it is possible to control high pressure more linearly. Herein, the term “pressure shot” refers to a phenomenon in which the amount of fluid flowing between the ball 130 and the body 122 rapidly increases, thereby causing rapid variation in pressure, during separation of the ball 130 from the body 122.

The ball 130 is disposed inside the first insert 120 to open/close the outlet 122b or control the opening amount thereof as the rod 150 moves. Such a ball 130 may be a rigid sphere having a specific gravity greater than that of the fluid in order to prevent the outlet 122b from being inadvertently opened.

The second insert 140 serves to control the pressure of the fluid supplied to the control port 116b, together with a poppet 152 of the rod 150, which will be described later. Such a second insert 140 is formed in a cup shape and is open at an upper end thereof, and the open upper end of the second insert 140 is coupled to the outlet 122b of the first insert 120. In addition, the first discharge holes 142 connected to the control port 116b are formed in a side of the second insert 140 and a second discharge hole 144 connected to the discharge port 116c is formed in a lower end of the second insert 140.

The rod 150 is a circular rod having a predetermined length and has the poppet 152 formed in the middle thereof. The rod 150 having such a shape is movably provided in the through-hole 118b and has an upper end extending to the ball 130 through the second discharge hole 144 and the outlet 122b. In addition, a lower end of the rod 150, more specifically, the lower end thereof protruding out of the core 114 is formed with caulking grooves 154 for fixing a plunger 230. The caulking grooves 154 are filled with a portion of the plunger 230 due to deformation thereof when the plunger 230 is caulked, so that it is possible to improve coupling efficiency and safety if a plurality of caulking grooves 154 is formed on the rod 150 in the longitudinal direction thereof.

Fig. 5 is an enlarged view of a portion of a solenoid of the pressure control valve according to this embodiment.

Referring to Fig. 5, the solenoid 200 will be described. The solenoid 200 includes the bobbin 220 having a coil 210 wound around an outer periphery thereof, the core 114 integrally formed with the lower end of the valve body 110 to be inserted through an upper portion of the bobbin 220, the plunger 230 installed to the lower end of the rod 150 coupled through the core 114, and a case 240 enclosing the bobbin 220 and the flange 112 formed at the lower end of the valve body 110.

An air gap G having a certain interval is formed between a lower end of the core 114 and an upper end of the plunger 230. This air gap G is formed to be in the range of 0.35 ~ 0.5 mm when the plunger 230 is in a lowered state (current is not applied), and 0.08 ~ 0.15 mm when the plunger 230 is in a raised state (current is applied). If the air gap G between the core 114 and the plunger 230 is maintained even when the plunger 230 is raised toward the core 114, it is possible to improve the responsiveness of the solenoid 200. That is, since the plunger 230 is not in contact with the core 114 even if the core 114 is magnetized by the application of current, the plunger 230 and the rod 150 are rapidly lowered when de-energized, so that it is possible to improve the responsiveness of the valve 100.

In addition, the case 240 has a lower end having a bent shape so that the lower end of the case 240 surrounds a lower surface of the bobbin 220 and is then inserted inside the bobbin. When the lower end of the case 240 is rolled up inside the bobbin 220, as described above, a fine gap between the plunger 230 and the core 114 can be defined to provide a smooth flow of magnetic force. That is, since the fine gap formed between the plunger 230 and the core 114 interrupts or reduces a flow of magnetic force, it is possible to smooth the flow of magnetic force as a gap between the magnetic parts is narrowed.

According to the solenoid 200 as configured above, in a state wherein no current is applied, the plunger 230 is maintained in the lowered state by the pressure of the fluid introduced into the operation space 126 and the weight of the rod 150 and the plunger 230. However, if current is applied to the solenoid 200 and a magnetic field is generated around the coil 210, the plunger 230 is raised and the core 114 is magnetized by the magnetic field generated around the coil 210, so that the plunger 230 is maintained in the raised state. Here, since the plunger 230 is not in contact with the core 114 even though the core 114 is magnetized as described above, the plunger 230 and the rod 150 can be rapidly lowered, when de-energized, thereby improving responsiveness of the valve 100.

Figs. 6 to 8 show operational states of the pressure control valve according to this embodiment.

Fig. 6 shows a state wherein current is not applied to the solenoid 200 of the pressure control valve according to this embodiment. In such a state, the rod 150 and the plunger 230 are lowered by the pressure and weight of the fluid introduced into the operation space 126 and positioned at its lowest end. Thus, since the upper end of the rod 150 is spaced apart from the ball 130 and thus the outlet 122b is closed by the ball 130, the fluid supplied through the supply ports 116a and the inlets 122a stays only in the operation space 126 of the first insert 120 and is not discharged to the outside.

Fig. 7 illustrates a state wherein current is applied to the solenoid 200 of the pressure control valve according to this embodiment. In such a state, a magnetic field is generated around the coil 210 and causes the plunger 230 to be raised. Then, the core 114 is magnetized by the magnetic field generated around the coil 210, so that the plunger 230 is fixed at the corresponding position. Thus, the upper end of the rod 150 pushes the ball 130 to cause the same to be spaced apart from the outlet 122b, so that the outlet 122b is open. Accordingly, the fluid in the operation space 126 is discharged to the control port 116b through the outlet 122b and the first discharge holes 142 of the second insert 140. At this time, a portion of the fluid supplied to the second insert 140 through the outlet 122b is transferred and discharged to the discharge port 116c through the second discharge hole 144.

According to the aforementioned principle, as the current applied to the solenoid 200 is large, the raising amount of the plunger 230 is increased and the opening amount of the outlet 122b is also increased, so that the control pressure of the fluid discharged to the control port 116b is increased. However, as the current applied to the solenoid 200 is small, the raising amount of the plunger 230 is decreased and the opening amount of the outlet 122b is also reduced, so that the control pressure of the fluid discharged to the control port 116b is decreased.

Fig. 8 shows a state wherein the current applied to the solenoid 200 of the pressure control valve according to this embodiment is at a maximum value. In such a state, a magnetic field is generated around the coil 210 and causes the plunger 230 to be maximally raised. Then, the core 114 is magnetized by the magnetic field generated around the coil 210, so that the plunger 230 is fixed at the corresponding position. Thus, the upper end of the rod 150 pushes the ball 130 to cause it to be spaced apart from the outlet 122b, so that the outlet 122b is fully opened. Accordingly, the fluid in the operation space 126 is discharged to the control port 116b through the outlet 122b and the first discharge holes 142 of the second insert 140. At this time, since the poppet 152 is raised together with the rod 150 and then closes the second discharge hole 144, the entirety of the fluid supplied to the second insert 140 through the outlet 122b is discharged to the control port 116b through the first discharge holes 142. That is, the control pressure of the fluid discharged to the control port 116b is maximized.

As described above, the pressure control valve according to this embodiment opens/closes the outlet 122b of the first insert 120 and the second discharge hole 144 of the second insert 140 or controls the opening amounts thereof using the ball 130 and the poppet 152 according to the current applied to the solenoid 200, whereby it is possible to effectively control the pressure of the fluid discharged to the control port 116b and to prevent unnecessary waste of fluid.

Although some embodiments have been described herein, it should be understood by those skilled in the art that these embodiments are given by way of illustration only, and that various modifications, variations, and alterations can be made without departing from the spirit and scope of the invention. Therefore, the scope of the invention should be limited only by the accompanying claims and equivalents thereof.

Claims

A pressure control valve, comprising:

a valve body having a supply port, a control port and a discharge port formed therein;

a first insert disposed inside the valve body, the first insert being formed with an inlet connected to the supply port and an outlet for discharging fluid supplied through the inlet;

a ball disposed inside the first insert to open/close the outlet;

a second insert coupled to the outlet side of the first insert, the second insert being formed with a first discharge hole connected to the control port and a second discharge hole connected to the discharge port; and

a rod movably provided to the valve body, the rod having one end extending toward the ball, the rod having a poppet formed in the middle thereof to open/close the second discharge hole.
The pressure control valve according to claim 1, wherein the first insert comprises an operation space receiving the ball therein, and the operation space comprises a guide protrusion for guiding movement of the ball and a guide groove for guiding discharge of fluid.
The pressure control valve according to claim 2, wherein a plurality of the guide protrusions and the guide grooves are radially disposed.
The pressure control valve according to claim 2, wherein the first insert is formed in a cup shape and is open at one end thereof, and the open end of the first insert is sealed by a cover.
The pressure control valve according to claim 4, wherein the inlet is formed on a side of the first insert, the outlet is formed on the other end of the first insert, and the operation space is formed between the inlet and the outlet.
The pressure control valve according to claim 5, wherein the cover comprises a protrusion protruding toward the operational space.
The pressure control valve according to claim 2, wherein a mounting space for receiving the first and second inserts is formed inside the valve body, some of an outer wall of the first insert is in close contact with an inner wall of the valve body, and the remainder of the outer wall is spaced apart from the inner wall of the valve body form a transfer path.
The pressure control valve according to claim 7, wherein the supply port is formed on the side of the valve body, the control port is formed on one end of the valve body, the inlet is formed at a position on a side of the first insert corresponding to the supply port, and the outlet is formed on the other end of the first insert, and the portion on the outer wall of the first insert where the inlet is formed is in close contact with the inner wall of the valve body.
The pressure control valve according to claim 1, further comprising a solenoid which moves the rod.
The pressure control valve according to claim 9, wherein the solenoid comprises:

a bobbin having a coil wound around an outer periphery thereof;

a core integrally formed with the valve body to be inserted through one end of the bobbin, the core having a through-hole into which the rod is coupled; and

a plunger provided to the other end of the rod and positioned within the bobbin.
The pressure control valve according to claim 10, wherein an air gap is formed between the core and the plunger.
The pressure control valve according to claim 11, wherein the air gap is in a range of 0.08 ~ 0.15 mm when the plunger is moved toward the core, and in a range of 0.35 ~ 0.5 mm when the plunger is moved away from the core.
The pressure control valve according to claim 10, wherein the solenoid further comprises a case enclosing a lower end of the valve body and the bobbin.
The pressure control valve according to claim 13, wherein a lower end of the case has a bent shape so as to be inserted into the bobbin.
The pressure control valve according to claim 9, wherein the other end of the rod with the plunger installed thereto is formed with a caulking groove.
The pressure control valve according to claim 15, wherein a plurality of the caulking grooves is formed in a longitudinal direction of the rod.
The pressure control valve according to claim 9, wherein the first insert comprises an operation space receiving the ball therein, and the operation space comprises a guide protrusion for guiding movement of the ball and a guide groove for guiding discharge of fluid.
The pressure control valve according to claim 17, wherein a plurality of the guide protrusions and the guide grooves are radially disposed.
The pressure control valve according to claim 17, wherein the first insert is formed in a cup shape and is open at one end thereof, and the open end of the first insert is sealed by a cover.
The pressure control valve according to claim 19, wherein the inlet is formed on a side of the first insert, the outlet is formed on the other end of the first insert, and the operation space is formed between the inlet and the outlet.
The pressure control valve according to claim 20, wherein the cover comprises a protrusion protruding toward the operational space.
The pressure control valve according to claim 17, wherein a mounting space for receiving the first and second insert is formed inside the valve body, some of an outer wall of the first insert is in close contact with an inner wall of the valve body, and the remainder of the outer wall is spaced apart from the inner wall of the valve body form a transfer path.
The pressure control valve according to claim 22, wherein the supply port is formed on the side of the valve body, the control port is formed on one end of the valve body, the inlet is formed at a position on a side of the first insert corresponding to the supply port, and the outlet is formed on the other end of the first insert, and the portion on the outer wall of the first insert where the inlet is formed is in close contact with the inner wall of the valve body.