JP3520747B2 - Method of manufacturing sleeve and solenoid spool valve using the sleeve - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a sleeve used for a pressure control electromagnetic spool valve and an electromagnetic spool valve using the sleeve.

[0002]

2. Description of the Related Art Conventionally, in an electromagnetic spool valve for pressure control, a characteristic as shown in FIG. 6 in which the control port pressure increases substantially linearly with an increase in exciting current flowing through a linear solenoid (hereinafter referred to as "normal Characteristic)) and, conversely, a characteristic as shown in FIG. 7 in which the control port pressure decreases almost linearly with the increase of the exciting current (hereinafter referred to as “reverse characteristic”). There are those that are roughly classified into the types that they have. In order to obtain such control port pressure characteristics, the positive characteristic type electromagnetic spool valve has, for example, the configuration shown in FIG. 8, and the reverse characteristic type electromagnetic spool valve has the configuration shown in FIG. As can be seen by comparing the two figures, the difference between the configurations of the two types of electromagnetic spool valves is that the shapes of the sleeves 92, 97 and the spools 93, 98 are different from each other. This enables hydraulic control according to the demands of the hydraulic circuit and the like.

[0003]

However, according to the above-described electromagnetic spool valve, the sleeves 92 and 97 must be formed in different shapes by aluminum die casting in order to obtain two different characteristics of forward and reverse. Two casting molds must be prepared. That is, as shown in FIGS. 8 and 9, when comparing the positive characteristic type sleeve 92 and the reverse characteristic type sleeve 97, the guide holes 92a and 97a formed in the axial direction and the annular groove formed in the inner peripheral wall are compared. 92b-e and 97b-e, radially formed supply port 921 and control port 971, control port 922 and supply port 972, drain port 925
And 975, even if they can be used in common, the main drain ports 923 and 973, the feedback ports 924 and 974, and the feedback grooves 927 and 977, which are completely different in formation position, must be formed by different casting molds according to forward and reverse characteristics. . Therefore, different casting molds are required for each characteristic of the electromagnetic spool valve, which causes a problem that costs required for manufacturing and managing the casting molds prevent reduction of product cost.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a sleeve manufacturing method and a sleeve manufacturing method capable of reducing the product cost of an electromagnetic spool valve. It is to provide an electromagnetic spool valve used.

[0005]

In order to achieve the above object, in the method of manufacturing a sleeve according to the first aspect of the present invention, an electromagnetic spool valve having a positive characteristic that the control pressure increases with an increase in the exciting current, and an increasing exciting current. A method for manufacturing a sleeve for use with an electromagnetic spool valve having the inverse characteristic of reducing control pressure with respect to a guide hole for slidably accommodating a spool by die casting, and one end of the guide hole. The adjustment hole having a diameter smaller than that of the guide hole, each port required for the positive characteristic and the reverse characteristic, and the feedback chamber formed between the guide hole and the adjustment hole are provided in common for the positive characteristic and the reverse characteristic. After the sleeve intermediate material is manufactured and after this die casting, the adjusting hole of the sleeve intermediate material is finished to a diameter larger than the inner diameter of the guide hole when used as a positive characteristic, and used as an inverse characteristic. In this case, processing to finish diameter than the inner diameter of the guide hole, and technical features that it has to be in a sleeve in accordance with the positive characteristic or inverse characteristic.

Further, in the sleeve manufacturing method according to the second aspect of the present invention, there is provided an electromagnetic spool valve having a positive characteristic in which the control pressure increases as the exciting current increases, and an inverse spool valve in which the control pressure decreases as the exciting current increases. A method for manufacturing a sleeve used for an electromagnetic spool valve having a characteristic, the guide hole for slidably accommodating a spool by die casting, and a guide hole formed at one end of the guide hole. Manufactures a sleeve intermediate material having a small diameter adjustment hole, each port required for normal characteristics and reverse characteristics, and a feedback chamber formed between the guide hole and the adjustment hole, which is common to normal characteristics and reverse characteristics,
After this die casting, the guide hole of the sleeve intermediate material is finished to a predetermined inner diameter, and the orifice opening to the feedback chamber is formed, and the adjustment hole of the sleeve intermediate material is used as a positive characteristic. For finishing with a larger diameter than the inner diameter of the guide hole and using it as a reverse characteristic, finish with a smaller diameter than the inner diameter of the guide hole to make a sleeve according to the normal characteristic or the reverse characteristic. This is a technical feature.

Further, in the electromagnetic spool valve using the sleeve according to the third aspect, the first port formed on one end side is formed in the axial direction toward the other end side so as to communicate with the first port. A guide hole, a second port communicating with the first port via the guide hole, formed on the other end side of the first port, and communicating with the first and second ports via the guide hole A third port formed on the other end side of the second port, a communication passage communicating with the second port and formed in an outer wall, and communicating with the second port via the communication passage and the guide. A feedback chamber that communicates with the opening end on the other end side of the hole, a sleeve having a differential pressure hole formed on the inner wall of the feedback chamber on the side opposite to the guide hole, and a sleeve slidably accommodated in the guide hole and axially displaced. Selectively connect each of the above ports And a spool in which a differential pressure generating portion formed in an outer diameter different from that of the land portion is slidably brought into contact with the end portion and the differential pressure hole, and is located on one end side of the sleeve and is on the other end side of the sleeve. An electromagnetic spool valve comprising: a biasing unit that biases the spool; and a linear solenoid unit that axially displaces the spool against the biasing force of the biasing unit when energized. Is
In the electromagnetic spool valve having the positive characteristic that the control pressure increases with the increase of the exciting current, the diameter is set larger than the outer diameter of the land portion of the spool, and the control pressure decreases with the increase of the exciting current. In the electromagnetic spool valve having the reverse characteristic, the diameter is set to be smaller than the outer diameter of the land portion of the spool, and the unnecessary port of the forward and reverse characteristics of the port is closed. Characterize.

According to the first aspect of the invention, the guide hole for slidably accommodating the spool, the adjusting hole having a diameter smaller than that of the guide hole formed at one end of the guide hole, and each of the characteristics required for the normal characteristic and the reverse characteristic are provided. A sleeve intermediate material having a positive characteristic and a reverse characteristic having a port and a feedback chamber formed between the guide hole and the adjusting hole is manufactured. When the adjusting hole of the sleeve intermediate material is used as a positive characteristic, it is finished to a diameter larger than the inner diameter of the guide hole, and when it is used as a reverse characteristic, it is finished to a diameter smaller than the inner diameter of the guide hole. The sleeve is designed according to the normal characteristics or the reverse characteristics. Accordingly, the sleeve intermediate member can be used in common even in the electromagnetic spool valves having two kinds of normal and reverse characteristics.

According to the second aspect of the present invention, the guide hole for slidably accommodating the spool, the adjusting hole having a diameter smaller than that of the guide hole formed at one end of the guide hole, and the respective characteristics required for the normal characteristic and the reverse characteristic are provided. A sleeve intermediate material having a positive characteristic and a reverse characteristic having a port and a feedback chamber formed between the guide hole and the adjusting hole is manufactured. Then, the guide hole of the sleeve intermediate material is finished to a predetermined inner diameter, and an orifice opening to the feedback chamber is formed. Further, when the adjustment hole of the sleeve intermediate material is used as a positive characteristic, the inner diameter of the guide hole is When finishing with a larger diameter and using it as an inverse characteristic, the sleeve is finished with a diameter smaller than the inner diameter of the guide hole to obtain a sleeve according to the regular characteristic or the inverse characteristic. Accordingly, the sleeve intermediate member can be used in common even in the electromagnetic spool valves having two kinds of normal and reverse characteristics.

According to the third aspect of the present invention, in the positive characteristic type electromagnetic spool valve, the sleeve intermediate member has a diameter such that the differential pressure generating portion set to a diameter larger than the outer diameter of the land portion of the spool can be slidably contacted. In the case of an electromagnetic spool valve of the reverse characteristic type, the differential pressure generating part, which is set to a diameter smaller than the outer diameter of the land part of the spool, makes sliding contact. It includes the step of processing the adjusting hole of the sleeve intermediate material to a possible diameter to form the differential pressure hole of the sleeve. That is, regardless of the forward / reverse characteristics, a sleeve intermediate material in which guide holes, holes such as ports and passages are formed regardless of the forward / reverse characteristics is used. It includes a step of processing only the diameter of the adjustment hole of the sleeve intermediate material to a diameter that can be contacted, and making the adjusted hole after processing the differential pressure hole of the sleeve. Thereby, even a solenoid spool valve having two kinds of different characteristics, normal and reverse, can be manufactured by using a common sleeve intermediate material.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a sleeve manufacturing method of the present invention and an electromagnetic spool valve using the sleeve will be described below with reference to the drawings. First, the structure of the sleeve intermediate member 52 according to the embodiment of the present invention will be described with reference to FIGS. 1, 2, and 3.

A sliding hole 52a (guide hole), which is a cylindrical long hole, is axially formed substantially in the center of the sleeve 52 on the axial line. The inner diameter of the sliding hole 52a is the land of the spool 56, which will be described later. The portions 57a and 57b are set to a size that allows sliding contact with the inside of the sliding hole 52a. Then, on the peripheral wall of the sliding hole 52a, annular grooves 61, 62, 63, 64 are sequentially formed from the one end side toward the other end side at a predetermined interval.

A coil spring chamber 66 which directly communicates with the sliding hole 52a is formed at one end on the axial line in the sleeve intermediate member 51, and an adjusting hole 54 is provided in the sliding hole 52a at the other end.
A shaft chamber 67 that communicates with each other is formed. The coil spring chamber 66 is a chamber that accommodates the coil spring 59 that biases the spool 56 in the sliding hole 52a, and the shaft chamber 67 is a chamber that accommodates the end of the shaft 38 that projects from the linear solenoid portion 30.

The adjusting hole 54, which connects the sliding hole 52a and the shaft chamber 67 to each other, is an unprocessed hole which is used as a differential pressure hole 54a or a differential pressure hole 54b, which is expanded to a predetermined inner diameter and will be described later. The hole diameter to be processed is selected according to the control pressure characteristics of 20. That is, the adjustment hole 54 is machined so that the inner diameter d1 is larger than the inner diameter of the sliding hole 52a.
The differential pressure hole 54a is formed in the sleeve 52 used in the positive characteristic type electromagnetic spool valve 20, and the adjustment hole 54 is processed to have an inner diameter d smaller than the inner diameter of the sliding hole 52a.
The second differential pressure hole 54b is molded into the sleeve 52 used in the electromagnetic spool valve 20 of the reverse characteristic type. By setting the inner diameter of the differential pressure hole after expanding the adjustment hole 54 in this way, it is possible to distribute the sleeve 52 to the positive characteristic type sleeve or the reverse characteristic type sleeve 52.
Has an inner diameter d1 set to be larger than the inner diameter of the sliding hole 52a,
This is also because the inner diameter d2 of the differential pressure hole 54b is set smaller than the inner diameter of the sliding hole 52a. That is, as will be described later, the size relationship between the inner diameters of the differential pressure holes 54 and the sliding holes 52a causes a difference in pressure receiving area of the land portion 57 of the spool 56,
This is because it determines the direction of action of the feedback hydraulic pressure.

On the outer peripheral wall of the sleeve 52, a long groove-like feedback path 68 (communication path) is formed in the axial direction.
This feedback path 68 is provided with an annular groove 62 and an annular groove 64 together with a port 58f and an orifice 58g described below.
Used to communicate with and. The annular groove 61 described above
~ 64, the coil spring chamber 66, each port 58a, 58b, 58c, 58 that communicates the inside and outside of the cylindrical wall of the sleeve 52.
d, 58e, 58f, 58h, and orifice 58g
In particular, all the ports are formed in the annular grooves 61 to 64, including the ports 58a, 58c, 58d and 58e, the necessity of which depends on the forward and reverse characteristics of the electromagnetic spool valve. That is, a port 58h is formed in the coil spring chamber 66, a port 58a (first port) and a port 58e (first port) are formed in the annular groove 61, and a port 58b (second port) is formed in the annular groove 62. And a port 58f (communication passage) are formed, the annular groove 63 is provided with a port 58c (third port) and a port 58d (third port), and the annular groove 64 is provided with an orifice 58g.
(Communication path) is formed. The orifice 58g and the port 58f not only communicate the inside and the outside of the cylinder wall, but are also formed at a position where they can be opened to the feedback passage 68 formed in the outer peripheral wall, and the pressure oil in the annular groove 62 is fed back to the feedback chamber described later. It is possible to return to 65. Among the ports 58a to 58e, those that are unnecessary depending on the forward and reverse characteristics of the electromagnetic spool valve function by closing the open end of the transmission housing 22 into which the electromagnetic spool valve is fitted and fixed. To lose.

The sleeve 52 described above is made of a sleeve intermediate material 51 formed by an aluminum die casting method. The sleeve intermediate material 51, as shown in FIG.
During die casting, the sliding hole 52a, the adjusting hole 54, the ports 58a to f, 58h, the annular grooves 61 to 64, the coil spring chamber 66, the shaft chamber 67 and the feedback path 6 are formed.
8 is molded. Then, after die casting, the adjusting hole 54 of the sleeve intermediate member 51 is finished to have a hole diameter d1 or d2 to form differential pressure holes 54a and 54b. at the same time,
The sliding hole 52a is finished to have a predetermined hole diameter, and the orifice 58g is additionally processed. Further, the outer circumference, the end surface of the sleeve intermediate member 51 and a screw hole into which a lid plug 60 described later is screwed are processed to complete the sleeve 52. In this manner, the two types of sleeves 52 used for the electromagnetic spool valves having the normal and reverse characteristics are manufactured from the common sleeve intermediate material 51. In the above embodiment, after the die casting, the sliding hole 52a, the orifice 58g and the like are processed in addition to the adjustment hole 54.
This is strictly related to the accuracy or molding of die casting, and if the required accuracy is secured by die casting, or if it can be die cast,
It is not absolutely necessary.

Next, the structure of the electromagnetic spool valve 20 manufactured by using the sleeve 52 described above will be described with reference to FIGS. FIG. 2 is a partial cross-sectional view showing a structure in which the electromagnetic spool valve 20 according to the present embodiment is fitted and fixed in a housing 22 such as a mission forming a hydraulic circuit or the like, and FIG. 3 is a line III-III in FIG. It is a sectional view. The electromagnetic spool valve 20 described with reference to FIGS. 2 to 4 is a positive characteristic type, and the electromagnetic spool valve 21 described with reference to FIG. 5 is a reverse characteristic type.

As shown in FIGS. 2 and 3, the electromagnetic spool valve 20 is roughly divided into a linear solenoid portion 30 and a spool valve portion 50a, and the linear solenoid portion 30 operates the spool valve portion 50a. So that they are coaxial with each other. Spool valve 50a
Mainly includes a sleeve 52 formed by subjecting the sleeve intermediate material 51 to a predetermined precision processing, and a sleeve 52.
2, a spool 56 accommodated in the shaft 2 so as to be slidable in the axial direction,
A coil spring 59 which is housed in the coil spring chamber 66 of the sleeve 52 and biases the spool 56 toward the linear solenoid portion 30, and an anti-linear solenoid portion 3 of the coil spring chamber 66.
It is composed of a lid plug 60 that closes the 0-side opening.

The sleeve 52 is the sleeve intermediate member 5 described above.
1 has been subjected to a predetermined precision processing, its structure is that the differential pressure hole 5 formed to have a diameter d1 larger than that of the sliding hole 52a.
The structure of the sleeve intermediate member 51 is basically the same as that of the sleeve intermediate member 51 except for 4a and the newly formed orifice. That is, since the solenoid spool valve 20 shown in FIGS. 2 to 4 is of the positive characteristic type, the inner diameter of the adjusting hole 54 of the sleeve intermediate member 51 is d1.
The diameter of the sleeve 52 is expanded so that the sleeve 52 having the differential pressure holes 54a is formed.

Here, in the electromagnetic spool valve 20 used in a hydraulic circuit such as a transmission, the above-mentioned port 58a,
The oil passages to which 58b, 58c, 58d, 58e, 58g, 58h are connected will be described. The port 58a communicating with the annular groove 61 is connected to a supply passage through which pressure oil is pumped from a pump (not shown). Annular groove 6
The port 58b communicating with 2 is connected to the output passage so that pressure-controlled pressure oil can be output to a component of a hydraulic circuit (not shown). The port 58d communicating with the annular groove 63 is connected to the main drain passage open to the atmosphere and is used for pressure adjustment by displacement of the spool 56. The port 58h communicating with the coil spring chamber 66 is also connected to the drain passage open to the atmosphere, and absorbs the pressure fluctuation in the coil spring chamber 66 due to the displacement of the spool 56. In addition, port 5
Since 8c and the port 58e are not used in the electromagnetic spool valve 20, they are closed by the housing 22.

The spool 56 accommodated slidably in the sliding hole 52a is provided with land portions 57a, 57b, 57c formed to have a diameter larger than that of the small diameter portion 56a and dispersed at predetermined positions in the axial direction. ing. That is, the land portion 57
a is formed at a position where a "lap amount La between the outer peripheral wall of the land portion 57a and the peripheral wall of the sliding hole 52a" that changes according to the axial displacement of the spool 56 is obtained, and the land portion 57b is formed by the spool. The "outer peripheral wall of the land portion 57b and the sliding hole 52" that changes in accordance with the axial displacement of 56
It is formed at a position where a lap amount Lb "with the peripheral wall of a can be obtained. Further, regarding the land portion 57c (differential pressure generating portion), the land portion 57c has a larger diameter than the land portion 57b and has a predetermined amount or more regardless of the axial displacement of the spool 56.
The outer peripheral wall and the peripheral wall of the sliding hole 52a are formed at a position where a lap amount can be obtained. Further, the land portion 57b and the land portion 57c sandwich the space formed by the annular groove 64 and the sliding hole 52a from the axial direction, and the respective end surfaces of the land portions 57b and 57c having different pressure receiving areas and the sliding hole 52a.
And the inner peripheral wall of the annular groove 64, the feedback chamber 6
It is located so as to form 5 partitions.

By constructing the spool 56 in this way, the lapping amount La is caused by the axial displacement of the spool 56.
And the lap amount Lb increase and decrease in opposite directions,
For example, most of the pressure oil filled in the annular groove 62 is adjacent to the annular groove (see FIG. 2) through the clearance between the outer peripheral wall of the land portion (reference numeral 57b in FIG. 2) having a smaller wrap amount and the peripheral wall of the sliding hole 52a. Then, it can be made to flow into the code 63). That is, among the annular grooves 61, 62, and 63 described above, between adjacent annular grooves, that is, the annular groove 6
The flow rate of the pressure oil between 1 and the annular groove 62 or between the annular groove 62 and the annular groove 63 can be controlled by the axial displacement of the spool 56.

Further, the land portion 57 is larger than the land portion 57b.
By forming c to have a large diameter, a difference in pressure receiving area can be provided on each end face. Therefore, the land portion 5
By forming both side walls of the feedback chamber 65 by the 7b and the land portion 57c, the feedback chamber 65 is formed.
The hydraulic pressure (hereinafter referred to as "feedback hydraulic pressure") due to the increase in the internal pressure of (3) can be applied to the land portion on the side having a large pressure receiving area, that is, the land portion 57c. As a result, the feedback hydraulic pressure due to the change in the internal pressure of the feedback chamber 65 is applied to the linear solenoid section 30 side direction.

Coil spring 5 which is a compression coil spring
9 (biasing means) is housed in the coil spring chamber 66, and biases the spool 56 in the direction of the linear solenoid portion 30. That is, the coil spring 59 has one end abutting against the end surface of the land portion 57a of the spool 56 and the other end closing the opening of the coil spring chamber 66.
The spool 56 and the lid stopper 60 are brought into contact with the
It is located so that it can be pinched and compressed by.

The lid plug 60 closes the opening of the coil spring chamber 66 on the side opposite to the linear solenoid portion 30, and is screwed into the end of the sleeve 52 so as to push the coil spring 59 into the coil spring chamber 66. . Then, since the initial compression rate of the coil spring 59 varies depending on the degree of the screwing depth, the initial spring force of the coil spring 59 is set to a predetermined value by adjusting the lid plug 60 to the adjusted predetermined screwing position. There is. Due to this initial spring force, the end surface of the spool 56 is always in contact with the shaft 38 of the linear solenoid portion 30, so that the shaft 38 is urged in the anti-suction direction of the linear solenoid portion 30.

The linear solenoid portion 30 is mainly composed of a cylindrical core 32 made of a magnetic material, a bobbin 33 mounted on the outer periphery of the core 32, a coil 34 wound around the bobbin 33, and a core 32. Shaft 38 which is made of a non-magnetic material and is inserted into the hollow hole, a plunger 42 which is made of a magnetic material and is attached to the shaft 38 so as to be located in the hollow hole of the core 32, and a cover 36 having a cup shape and covering the coil 34. It consists of and.

A flange portion 32a is formed at the end of the core 32 on the spool valve portion 50a side.
2a, the linear solenoid portion 30 of the sleeve 52 described above
The side edges are fixed. Further, the core 32 is formed with a hollow hole through which the shaft 38 can slide in the axial direction via the bearing 40, and a yoke portion (not shown) capable of electromagnetically attracting the plunger 42 attached to the shaft 38. ing.

A coil 34, which is an electromagnetic coil, is formed by winding a conductive wire around the outer periphery of the bobbin 33 mounted on the outer periphery of the core 32 a predetermined number of times. Then, when an exciting current is supplied from an external power supply control unit (not shown), the coil 34 generates magnetic lines of force, forming a magnetic circuit with the core 32 made of a magnetic material, the cover 36 and the plunger 42 as magnetic paths. . As a result, the plunger 42, which is attached to the shaft 38 and is movable in the axial direction, moves to the coil 3
4 is electromagnetically attracted to the yoke portion of the core 32 by energization,
It moves in the direction of the spool valve portion 50a.

The shaft 38 is inserted into a bearing 40 fixed in the hollow hole of the core 32, a plunger 42 is attached to one end thereof, and the other end is urged by the coil spring 59 described above. The end surface of the spool 56 is always in contact. As a result, the shaft 38 is constantly urged in the anti-suction direction of the linear solenoid portion 30.

The cover 36 formed in a cup shape includes the core 32, the bobbin 33, the coil 34, and the shaft 3 described above.
8, the bearing 40 and the plunger 42 are located around the coil 34 so as to cover them, and the peripheral edge of the opening end is fixed to the flange 32a of the core 32 and the end of the sleeve 52 on the linear solenoid 30 side. . And
The cover 36 prevents external impacts and foreign matter from entering the linear solenoid portion 30 and also prevents the linear solenoid portion 3 from being lubricated, insulated, and cooled.
Holds the oil that fills the 0 interior space.

With the above structure, the axial displacement of the spool 56 slidably accommodated in the sliding hole 52a of the sleeve 52 is caused by the electromagnetic attraction force of the linear solenoid portion 30, the biasing force of the coil spring 59, and the feedback chamber 65. The ratio of the lap amount La of the land portion 57a to the sliding hole 52a and the lap amount Lb of the land portion 57b is controlled by the balance with the feedback hydraulic pressure due to the change in the internal pressure.

Next, the positive characteristic type solenoid spool valve 2
The operation of 0 will be described with reference to FIGS. 4 and 6. Figure 4
As shown in (A), the magnetic line of force of the coil 34 does not occur in the state where the exciting current is not applied to the linear solenoid portion 30 (or when the minimum current within the control range is applied by the exciting current). Due to the spring force, the spool 56 and the plunger 42 are located on the leftmost side in FIG. That is, the spool 56 is closest to the linear solenoid portion 30, and the lap amount La between the outer peripheral wall of the land portion 57a and the peripheral wall of the sliding hole 52a is maximized, while the outer peripheral wall of the land portion 57b and the peripheral wall of the sliding hole 52a are maximized. It moves to the position where the lap amount Lb becomes the minimum, and the shaft 3
8 moves to a position where the distance between the plunger 42 and the yoke is maximized. As a result, the magnitude relationship between the lap amount La and the lap amount Lb is La> Lb, so that the supply passage from the pump (not shown), the port 58a, and the lap amount La are
Clearance (the outer peripheral wall of the land portion 57a and the sliding hole 52)
The overlap amount of the lapping amount Lb from the annular groove 62 (the overlapping portion of the outer peripheral wall of the land portion 57b and the peripheral wall of the sliding hole 52a) is larger than the amount of pressure oil that is pressure-fed to the annular groove 62 via the overlapping portion of a. ) And the amount of pressure oil flowing out to the main drain open to the atmosphere via the port 58d becomes much larger. Therefore, in the non-energized state of the linear solenoid part 30 (or when the minimum current within the control range by the exciting current is energized), the pressure flowing from the annular groove 62 to the main drain is smaller than the pressure oil supplied from the pump to the annular groove 62. Since the amount of oil (arrow α shown in FIG. 4A) is larger, the pressure oil output from the port 58b is output to the hydraulic circuit or the like as the lowest control pressure as shown in FIG.

On the other hand, when an exciting current exceeding the minimum current within the control range is applied to the linear solenoid section 30, magnetic lines of force are generated in the coil 34 and a magnetic circuit using the core 32, the cover 36 and the plunger 42 as magnetic paths. To form. As a result, the electromagnetic attraction force according to the magnitude of the exciting current acts between the yoke portion and the plunger 42, and the movement of the plunger 42 electromagnetically attracted to the yoke portion causes the shaft 38 to move.
Urges the spool 56 in the direction of the coil spring 59 against the urging force of the coil spring 59, and displaces the spool 56 until the electromagnetic attraction force of the coil 34 and the spring force of the coil spring 59 are balanced. . Then, La> Lb
The difference between the lap amount La and the lap amount Lb, which have a magnitude relationship, gradually becomes smaller, and the difference becomes smaller as the exciting current increases. Further, the magnitude relationship between the lap quantity La and the lap quantity Lb reverses ( La <Lb), and the spool 56 moves to the rightmost side shown in FIG. Therefore, in the energized state of the linear solenoid portion 30 (at the maximum current within the control range due to the exciting current), the pressure oil supplied from the pump to the annular groove 62 is smaller than the pressure oil flowing from the annular groove 62 to the main drain (Fig. Since the arrow β) shown in 4 (B) has a larger amount, the pressure oil output from the port 58b is output to the hydraulic circuit or the like as the highest control pressure as shown in FIG.

As described above, the displacement of the spool 56 is mainly controlled by the amount of exciting current, but the electromagnetic spool valve 20 according to the present embodiment controls displacement of the spool 56 by factors other than this amount of current. It is being appreciated. That is, the pressure oil in the annular groove 62 is not only output to the hydraulic circuit or the like via the port 58b, but also returned to the feedback chamber 65 via the port 58f, the feedback path 68, and the orifice 58g. The hydraulic pressure obtained by multiplying the pressure by the pressure receiving area difference between the land portion 57b and the land portion 57c is used as the feedback hydraulic pressure, and the coil spring 5
It acts in addition to the spring force of 9 and thereby controls the spool 56 so that the control pressure becomes a value according to the exciting current.

Next, the inverse characteristic type electromagnetic spool valve 21
The configuration, particularly, the configuration and operation of the spool valve portion 50b will be described with reference to FIGS. The configuration of the inverse characteristic type electromagnetic spool valve 21 is also the same as the configuration of the positive characteristic type electromagnetic spool valve 20 described above.
0 and the spool valve portion 50b, and the configuration of the linear solenoid portion 30 is the same as that of the electromagnetic spool valve 20. Therefore, here, the configuration of the spool valve portion 50b will be described with reference to FIG.

As shown in FIG. 5, the structure of the spool valve portion 50b is substantially the same as that of the spool valve portion 50a for the positive characteristic type, and the sleeve intermediate member 51 is formed by subjecting the sleeve intermediate material 51 to a predetermined process. Inner diameter d of the differential pressure hole 54b of 52
2 and the outer diameter of the land portion 77c of the spool 76 are different from those of the positive characteristic type spool valve portion 50a.

Since the sleeve 52 of the spool valve portion 50b is obtained by subjecting the sleeve intermediate member 51 described above to predetermined precision processing, its construction is smaller than the sliding hole 52a by a diameter d2.
The configuration of the sleeve intermediate member 51 is basically the same as that of the sleeve intermediate member 51 except for the differential pressure hole 54b molded in and the newly formed orifice. That is, since the electromagnetic spool valve 21 shown in FIG. 5 is of the reverse characteristic type, the adjustment hole 5 of the sleeve intermediate member 51
No. 4 has a differential pressure hole 54 by being expanded so that the inner diameter becomes d2.
It is molded into a sleeve 52 having b.

The spool 76 has substantially the same structure as the spool 56 for the positive characteristic type, and has land portions 77a, 77.
b and 77c are respectively formed at predetermined locations dispersed in the axial direction. Of these land portions, the land portion 77a and the land portion 77b are configured in the same manner as the land portion 57a and the land portion 57b of the spool 56 for the positive characteristic type, and therefore, the outer peripheral wall of the land portion 77a and the sliding hole 52a. A lap amount La is obtained between the outer peripheral wall of the land portion 77b and the peripheral wall of the sliding hole 52a. On the other hand, the land portion 77c (differential pressure generation portion) has a smaller diameter than the land portion 77b.
Further, it is formed at a position where a predetermined amount or more of the outer peripheral wall of the land portion 77c and the peripheral wall of the sliding hole 52a and the lapping amount can be obtained regardless of the axial displacement of the spool 76. The feedback chamber 65 is defined by the end surfaces of the lands 77b and 77c having different pressure receiving areas, the sliding hole 52a, and the inner peripheral wall of the annular groove 64.

In the electromagnetic spool valve 21, the annular groove 6
The port 58e communicating with 1 is connected to the main drain passage open to the atmosphere and is used for pressure adjustment by the displacement of the spool 76 described above. Further, the port 58b communicating with the annular groove 62 is connected to the output passage to enable the pressure-controlled pressure oil to be output to a component of a hydraulic circuit (not shown). Further, the port 58c communicating with the annular groove 63 is connected to a supply passage through which pressure oil is pumped from a pump (not shown). The port 58h communicating with the coil spring chamber 66 is also connected to the drain passage open to the atmosphere, and absorbs the pressure fluctuation in the coil spring chamber 66 due to the displacement of the spool 76. Incidentally, the port 58a and the port 58d
Is not used in the electromagnetic spool valve 21, and is closed by the housing 22.

Next, the operation of the reverse characteristic type electromagnetic spool valve 21 having the above-mentioned structure will be described with reference to FIGS. As shown in FIG. 5A, in the state where the exciting current is not applied to the linear solenoid portion 30 (or when the minimum current within the control range is applied by the exciting current), the magnetic line of force of the coil 34 is not generated, and thus the coil spring 59. Due to the initial spring force, the spool 76 and the plunger 42 are located on the leftmost side in FIG. Therefore, the land portion 7
7a and the peripheral wall of the sliding hole 52a and the lapping amount La is maximized, while the peripheral wall of the land portion 77b and the sliding hole 52a.
And the lap amount Lb is minimum, and the magnitude relationship between the lap amount La and the lap amount Lb is La> Lb. for that reason,
Rather than the clearance of the lapping amount La from the annular groove 62 and the amount of pressure oil flowing out to the main drain opened to the atmosphere via the port 58e, the annular groove is passed from the pump (not shown) via the supply passage, the port 58c and the lapping amount Lb. The amount of pressure oil sent to 62 is much higher.
Therefore, when the linear solenoid portion 30 is in the non-energized state (or when the minimum current within the control range by the exciting current is energized), the pressure supplied from the pump to the annular groove 62 is larger than the pressure oil flowing from the annular groove 62 to the main drain. Oil (Fig. 5
Since the arrow γ) shown in FIG.
As shown in, the pressure oil output from the port 58b is output to the hydraulic circuit or the like as the highest control pressure.

On the other hand, when an exciting current exceeding the minimum current within the control range is applied to the linear solenoid section 30, an electromagnetic attractive force corresponding to the magnitude of the exciting current acts between the yoke section and the plunger 42. To the position where the electromagnetic attraction force of the coil 34 and the spring force of the coil spring 59 are balanced. Then, La ＞ L
The difference between the lap amount La and the lap amount Lb, which have a magnitude relationship with b, gradually decreases, and the difference becomes smaller as the exciting current increases, and further, the lap amount La and the lap amount Lb.
5 is reversed (La <Lb), and the spool 76 moves to the rightmost side shown in FIG. Therefore, in the energized state of the linear solenoid portion 30 (at the maximum current within the control range due to the exciting current), the pressure oil flowing from the annular groove 62 to the main drain is larger than the pressure oil supplied from the pump to the annular groove 62 (Fig. Since the arrow δ) shown in FIG. 5B has a larger amount, the pressure oil output from the port 58b is output to the hydraulic circuit or the like as the lowest control pressure as shown in FIG.

As described above, the displacement of the spool 76 is symmetrical to that of the spool 56 for the positive characteristic type, and the port 58f,
The hydraulic pressure obtained by multiplying the feedback pressure returned to the feedback chamber 65 via the feedback path 68 and the orifice 58g by the pressure receiving area difference between the land portion 77b and the land portion 77c is used as the feedback hydraulic pressure to be the electromagnetic attraction force of the linear solenoid portion 30. The spool 56 is additionally operated and feedback-controlled for the spool 56.

As described above, according to this embodiment,
The sleeve intermediate material 51 molded by the aluminum die casting method has holes or the like required for the sleeve 52 of the electromagnetic spool valve, that is, the sliding holes 52a, regardless of the positive and negative characteristics.
The adjustment hole 54, the ports 58a to f and 58h, the orifice 58g, the annular grooves 61 to 64, the coil spring chamber 66, the shaft chamber 67, and the feedback path 68 are formed, and then the adjustment holes having different inner diameters due to the forward and reverse characteristics. 54 is expanded to a predetermined inner diameter in a post process, and unnecessary ports are closed by a housing due to the forward and reverse characteristics. As a result, one type of sleeve intermediate material 51 can be used for two types of electromagnetic spool valves having different characteristics, that is, aluminum die casting for forming the sleeve intermediate material 51, that is, the sleeve 52 before processing. It is not necessary to prepare two types of molds for each of the forward and reverse characteristics, and one type of casting die can be used to mold the sleeve of the electromagnetic spool valve having two different forward and reverse characteristics. Therefore, the cost required for manufacturing and managing the casting mold can be reduced from the conventional two types to one type, and the product cost of the electromagnetic spool valve can be reduced.

In the above-described embodiment, an example in which unnecessary ports due to the forward and reverse characteristics are closed by the inner circumference of the housing 22 into which the soo rib 52 is fitted has been described, but individual ports are plugged. It may be closed by closing.

[0045]

According to the invention described in the claims, the adjusting hole formed in the sleeve intermediate member by die casting is machined to have a diameter larger than the inner diameter of the guide hole when used in the positive characteristic type electromagnetic spool valve. When used for a solenoid valve of the reverse characteristic type, the sleeve of the solenoid spool valve is formed by processing to a diameter smaller than the inner diameter of the guide hole. That is, since the sleeve intermediate member is formed with guide holes, holes and passages such as ports required for the sleeve regardless of the forward and reverse characteristics, the adjustment hole is adjusted according to the forward and reverse characteristics of the electromagnetic spool valve. If the diameter of the sleeve is machined to be larger or smaller than the inner diameter of the guide hole, the sleeve intermediate material can be commonly used even in the electromagnetic spool valves having two different kinds of forward and reverse characteristics. As a result, it is not necessary to prepare two types of sleeve intermediate materials, for example, casting dies for molding the sleeve before processing, for each of the forward and reverse characteristics, and one type of casting die or the like has two different forward and reverse characteristics. The sleeve of the solenoid spool valve can be molded. Therefore, it is possible to reduce the cost required for manufacturing and managing the casting mold and the like, which has the effect of reducing the product cost of the electromagnetic spool valve.

[Brief description of drawings]

FIG. 1 (A) is an axial sectional view showing a sleeve intermediate material according to an embodiment of the present invention, and FIG. 1 (B) is the above (A).
It is a BB sectional view shown in FIG.

FIG. 2 is a partial cross-sectional view showing an electromagnetic spool valve using a sleeve (for a positive characteristic type) obtained by processing a sleeve intermediate material according to an embodiment of the present invention.

3 is a sectional view taken along line III-III shown in FIG.

FIG. 4 is an axial cross-sectional view showing a spool valve portion of a positive characteristic type electromagnetic spool valve. FIG. 4 (A) shows a spool state when not energized, and FIG. 4 (B) shows a spool state when energized. It is shown.

FIG. 5 is an axial sectional view showing a spool valve portion of an inverse characteristic type electromagnetic spool valve, FIG. 5 (A) shows a spool state when not energized, and FIG. 5 (B) shows a spool state when energized. It is shown.

FIG. 6 is a characteristic diagram showing a change in control pressure with respect to an exciting current in a positive characteristic type electromagnetic spool valve.

FIG. 7 is a characteristic diagram showing a change in control pressure with respect to an exciting current in an inverse characteristic type electromagnetic spool valve.

FIG. 8 is an axial sectional view showing a spool valve portion of a positive characteristic type electromagnetic spool valve using a conventional sleeve intermediate material.

FIG. 9 is an axial sectional view showing a spool valve portion of an electromagnetic spool valve of a reverse characteristic type using a conventional sleeve intermediate material.

[Explanation of symbols]

20, 21 solenoid spool valve 30 Linear solenoid part 50a, b Spool valve part 51 Sleeve intermediate material 52 Sleeve 52a Sliding hole (guide hole) 54 adjustment hole 54a, b Differential pressure hole 56, 76 spool 57a, b Land section 57c Land portion (differential pressure generating portion) 58a, e port (first port) 58b port (2nd port) 58c, d port (3rd port) 58f port (communication passage) 58g Orifice (communicating passage) 59 Coil spring (biasing means) 65 Feedback Room 68 Feedback path (communication path) 77a, b Land section 77c Land portion (differential pressure generating portion)

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-9-166238 (JP, A) JP-A-10-184938 (JP, A) JP-A-6-109148 (JP, A) JP-A-8- 14432 (JP, A) Actual flat 7-8677 (JP, U) Actual flat 5-30663 (JP, U) Actual flat 3-117178 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16K 31/06-31/11 F16K 27/04 F16K 3/24-3/36 F16K 11/07

Claims (3)

(57) [Claims] 1. A sleeve used for an electromagnetic spool valve having a positive characteristic in which a control pressure increases with an increase in an exciting current and an electromagnetic spool valve having an inverse characteristic in which a control pressure decreases with an increase in an exciting current. A guide hole for slidably accommodating the spool by die casting, an adjustment hole having a diameter smaller than that of the guide hole formed at one end of the guide hole, and a positive characteristic and a reverse characteristic required. A sleeve intermediate material having common characteristics and reverse characteristics including a feedback chamber formed between each port, the guide hole and the adjustment hole is manufactured, and after this die casting, the adjustment hole of the sleeve intermediate material is formed. When used as a positive characteristic, finish processing to a diameter larger than the inner diameter of the guide hole, and when used as a reverse characteristic,
A method of manufacturing a sleeve, characterized in that the sleeve is finished into a diameter smaller than the inner diameter of the guide hole to obtain a sleeve according to a positive characteristic or a reverse characteristic. 2. A sleeve used for an electromagnetic spool valve having a positive characteristic in which a control pressure increases with an increase in exciting current and an electromagnetic spool valve having a reverse characteristic in which a control pressure decreases with an increasing exciting current. A guide hole for slidably accommodating the spool by die casting, an adjustment hole having a diameter smaller than that of the guide hole formed at one end of the guide hole, and a positive characteristic and a reverse characteristic required. A sleeve intermediate material having common characteristics and reverse characteristics including a feedback chamber formed between each port, the guide hole and the adjustment hole is manufactured, and after this die casting, the guide hole of the sleeve intermediate material is formed. When finishing processing to a predetermined inner diameter, forming an orifice that opens to the feedback chamber, and when using the adjustment hole of the sleeve intermediate material as a positive characteristic, When finished with a diameter larger than the inner diameter of the guide hole and used as a reverse characteristic, it is finished with a diameter smaller than the inner diameter of the guide hole to form a sleeve according to the normal characteristic or the reverse characteristic. Manufacturing method of sleeve. 3. A first port formed on one end side, a guide hole communicating with the first port and formed axially toward the other end side, and communicating with the first port via the guide hole. A second port formed on the other end side of the first port,
A third port communicating with the first and second ports via the guide hole and formed on the other end side of the second port; a communication passage communicating with the second port and formed in an outer wall;
A feedback chamber that communicates with the second port via the communication passage and communicates with the other end side opening end of the guide hole, and a differential pressure hole formed on an inner wall of the feedback chamber opposite to the guide hole. A sleeve, a land portion slidably accommodated in the guide hole and selectively communicating the respective ports by axial displacement, and a difference formed by sliding contact with the differential pressure hole and having an outer diameter different from that of the land portion. A spool on which a pressure generating portion is formed; a biasing unit located at one end side of the sleeve for biasing the spool toward the other end side of the sleeve; An electromagnetic spool valve having a linear solenoid section for axially displacing the spool, wherein the differential pressure generating section is an electromagnetic spool valve having a positive characteristic that the control pressure increases with an increase in exciting current. In the electromagnetic spool valve having the reverse characteristic that the outer diameter of the land portion of the spool is set to be larger and the control pressure decreases with an increase in the exciting current, the land portion of the spool is An electromagnetic spool valve using a sleeve, which is set to have a smaller diameter than the outer diameter and is configured to close an unnecessary port of the above ports due to its forward and reverse characteristics.