JPH0221081A - Electromagnetic solenoid for hydraulic control - Google Patents

Abstract

PURPOSE:To improve the magnetic efficiency of a coil, by shaft-supporting through a bearing a center rod provided on a side facing the opposing vacant space portion of a movable iron core, against a fixed iron core. CONSTITUTION:A passage 17a penetrating through the center portion of a movable iron core 6 longitudinally, is provided, and a center rod 25 whose part possesses this passage is provided at the movable iron core 6. A bearing bush 26 which extends the center rod 25 to the internal vacant space portion of a fixed iron core 2 and also, guides this rod 25, is provided on the internal vacant space side which is the tip of the conical part of the fixed iron core 2. A bearing bush 27 which guides the outer perimeter portion of the movable iron core 6 is formed short and also, out of a magnetic material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] This invention relates to an improvement in an electromagnetic solenoid for hydraulic control that is coupled to and controlled by a hydraulic control valve.

[Conventional technology]

FIG. 4 is a sectional view showing a hydraulic control valve and a conventional hydraulic control electromagnetic solenoid that controls the hydraulic control valve. First, the electromagnetic solenoid for hydraulic control will be explained. In the figure, (1) is the case. A fixed iron core (2) is integrally provided at one end of the case (1), and (3) is an end member attached to the other end of the case (1). These members (1), (2),
(3) forms a magnetic circuit. (4) is a solenoid coil, and (5) is a winding frame made of synthetic resin material.

A solenoid coil (4) is wound around a winding frame (5) and housed in a case (1). (6) is a movable iron core, (7
) is the output shaft. The movable core (6) is slidably mounted in the central shaft hole of the winding frame (5) within the case (1), and the output shaft (7) is fixed to this movable core (6). This output shaft (6) is slidably mounted in the central shaft hole of the fixed iron core (2) and protrudes outward from the case (1).What has been described above is an electromagnetic solenoid for hydraulic control. This is because when current is applied to the solenoid coil (4), the movable core (6) is attracted to the fixed core (2), and when the current is turned off, the movable core (6) is allowed to separate from the fixed core (2). Thus, the output shaft (7) is displaced in the axial direction.

Such a hydraulic control electromagnetic solenoid is used in combination with a hydraulic control valve (11) as shown. The hydraulic control valve (11) consists of a valve body (12), a spool (13), and a return spring (14), and the spool (13) is connected to the output shaft (7). , valve body (
12) includes hydraulic flow paths (12a), (12b), (12c).
) is formed.

Thus, when the solenoid coil (4) is energized, the movable core (6) resists the force of the return spring (14) and returns to the fixed core (
2), the spool (13) is displaced in the axial direction so that the hydraulic flow paths (12b) and (12c) communicate with each other, and when the energization is stopped, the movable iron core (6) returns to the spring state. The force (14) causes the spool (13) to be returned in the direction away from the fixed iron core (2), and accordingly the spool (13) is displaced in the opposite direction to connect the hydraulic flow paths (12a) and (12b). We will be able to communicate. In this way, communication of the hydraulic flow path is switched.

In such an electromagnetic solenoid for hydraulic control, when the case (1) or the space between the fixed iron core (2) and the valve body (12) is filled with hydraulic oil (coming from the hydraulic control valve (11)), the movable iron core (6) During movement, hydraulic oil flows between the inner circumferential surface of the center shaft hole of the winding frame (5) and the outer circumferential surface of the movable core (6), and between the inner circumferential surface of the center shaft hole of the fixed core (2). and the outer peripheral surface of the output shaft (7). Thus, fluid resistance increases when the movable core (6) moves, hindering smooth movement of the movable core (6) and reducing speed response.

A solution to this problem is disclosed in Utility Model Application No. 115529/1983. The electromagnetic solenoid for hydraulic control is shown in Fig. 3. In the figure, (1), (2), (3), (4)
, (5), (6), (11) and (13) are the same members as shown in FIG. 4 or corresponding parts. (1
7) is an output shaft fixed to a movable iron core (6), but this is different from the conventional one, and has a communication hole (1
7a). Furthermore, this output shaft (17) has radial communication holes (17b) and (17c) at the positions shown in the figure.
has. The movable iron core (6) also has a through hole. In this way, the hydraulic oil flows as shown by the arrow, allowing smooth movement of the movable iron core (6).

After that, improvements were made and an electromagnetic solenoid for hydraulic control as shown in FIG. 2 was developed. FIG. 2(a) is a longitudinal cross-sectional view thereof, and FIG. 2(b) is a cross-sectional view taken along the line AA shown in FIG. 2(a). In the figure, (1), (2),
(3), (4), (5), (6) and (14) are the third
The same parts or equivalent parts as in the illustrations are shown. First, this hydraulic control electromagnetic solenoid differs from those described above in that the output shaft (7) does not pass through the fixed iron core (2). Furthermore, this hydraulic control electromagnetic solenoid itself is equipped with a return spring (14), which is different from the above-mentioned one. In other words, since the output shaft (7) does not pass through the fixed iron core (2), there are fewer chambers for hydraulic oil to flow back and forth, and there are fewer obstacles to the movement of the movable iron core (6), and the return spring (14) ), the output shaft (7) can be actively reciprocated using only this hydraulic control electromagnetic solenoid, which is an improvement over the previous model.

To explain the operation of this electromagnetic solenoid for hydraulic control, although it is a bit complicated, when current is passed through the solenoid coil (4), the movable iron core (
6) is attracted and when the energization is stopped, the movable iron core (6)
is moved forward by a return spring (14). Thus, the output shaft (7) is displaced in the axial direction. In order to increase the suction efficiency of the movable core (6), the opposing end surfaces of the fixed core (2) and the movable core (6) are formed into complementary conical shapes.

An opposing cavity (18) is formed between these conical end faces. Furthermore, a bearing sleeve (19) is required to guide the movable core (6) rearward. This bearing sleeve (
19) is non-magnetic (brass) and prevents a magnetic path from being formed through this member. When a magnetic path is formed through this member, the fixed iron core (2) connects to the movable iron core (
This is because the power to attract 6) is reduced. A movable iron core (6) is guided in sliding contact with this bearing sleeve (19). A groove (20) extending in the axial direction is formed around the movable core (6) to allow hydraulic fluid to enter and exit when the movable core (6) moves in the axial direction. By the way, the reason why this groove (20) is provided on the outer peripheral surface of the movable core (6), unlike the longitudinal flow hole (17a) in FIG. 3, is because the movable core (6) is connected to the fixed core (2). When approaching, hydraulic oil remains on the outer periphery of the opposing cavity (18) and the movable iron core (
This is to prevent the operation of step 6) from slowing down. Furthermore, (21),
(22) and (23) are 0 rings.

[Problems to be Solved by the Invention] In the conventional electromagnetic solenoid for hydraulic control shown in FIG. 2, as the movable core (6) approaches the fixed core (2), the magnetic path is blocked by the non-magnetic bearing sleeve (19). Moreover, since the groove (20) is provided on the circumferential surface of the movable core (6), it is not favorable for forming a magnetic path between the case (1) and the movable core (6). There was a problem in that the electromagnetic efficiency of the solenoid coil (4) decreased.

This invention was made to solve these problems, and aims to provide a compact solenoid coil (4) with good electromagnetic efficiency, and furthermore, to obtain a compact electromagnetic solenoid for hydraulic control. shall be.

[Means for Solving the Problems] An electromagnetic solenoid for hydraulic control according to the present invention has a conical solenoid of a fixed iron core (2) extending from an outer circumferential part of a conical opposed gap part (18) to an inner gap part of a fixed iron core (2). A radial passageway (24) bypassing the shaped portion is formed, and the conventional outer peripheral groove (24) is formed.
20), a passage (17a) passing through the center of the movable core (6) in the longitudinal direction is provided, and a center rod (25) having this passage (17a) as a part is provided in the movable core (6). This is extended to the internal cavity of the fixed iron core (2), and a bearing bush (26) for guiding this center rod (25) is provided at the tip of the conical part of the fixed iron core (2) on the side of the internal cavity, The bearing bush (27) that guides the outer circumference of the movable iron core (6) is short and made of a magnetic material.

[Function] In this invention, since the bypass passage (24) is provided, there is no need to provide the groove (20) on the outer peripheral surface of the movable iron core (6) as in the conventional case.
a), and since the central rod (25) is provided on the movable core (6) and guided by the fixed core (2), it is not necessary to use the conventional long bearing sleeve (1).
9) is not required. The long bearing sleeve (19) must be made of non-magnetic material, but if it can be made shorter, it can be made of a magnetic material.

[Embodiment] FIG. 1 shows an electromagnetic solenoid for hydraulic control according to an embodiment of the present invention. FIG. 1(a) is a longitudinal sectional view of the first
FIG. 1(b) is a cross-sectional view taken along line BB in FIG. 1(a). The upper half of Figure 1 (a) shows the state when no current is passed through the coil (4), and the lower half shows the state when no current is passed through the coil (4).
This shows the state when current is passed through. In the figure, (
1) - (6), (14), (18), (21) - (23
) are the same as those shown in FIG. 2, so their explanation will be omitted. The output shaft (17) is made of a non-magnetic material, and unlike the output shaft in FIG. 2, it has a passage (17a) passing through the center in the longitudinal direction. And it has radially open passages (17b), (17C). (25) is a central iron concentrically fixed to the output shaft (17).

This rod (25) is made of non-magnetic material and has a part of the passage (17a). Therefore, the movable iron core (6
) is a third groove (20) on the outer periphery as shown in FIG.
It will have a conventional passageway as shown in the figure. However, the novel points of the present invention are as follows. That is, (24) is a radial passageway extending in the radial direction that directly connects the outer circumference of the conical opposing gap (18) and the internal gap of the fixed iron core (2). As a result, when the movable iron core (6) is attracted to the fixed iron core (2) and approaches it, the hydraulic oil in the outer periphery of the conical opposing gap (I8) flows from this radial passage (24) to the central part. It flows through the passage (17a) to other parts. (26) is a bearing bushing provided to guide the center rod (25) at the tip of the internal cavity of the fixed core (2), that is, on the front side of the radial passage (24). This has a Teflon coating on the inner periphery to improve sliding. (27) is a bearing bush provided on the front side of the casing (1) to guide the movable iron core (6), and the inner circumference of this bushing is also coated with Teflon to improve sliding.

The operation of the electromagnetic solenoid for hydraulic control according to the present invention is as follows.
It is basically the same as the one shown in the figure, but its performance is different. That is, as can be understood from FIG.
), especially the bearing bushing (27
) can be made shorter. Therefore, this bearing bush (27) can be made of a magnetic material such as 5PCE (iron). If a long bearing sleeve (19) as shown in Fig. 2 is made of magnetic material, a magnetic path will be formed from the fixed core (2) through this bearing sleeve (19), and the movable core (6) will be This reduces suction efficiency. According to the present invention, such a problem does not occur, and by making the bearing bush (27) a magnetic material, the formation of a magnetic path between the case (1), which also serves as a yoke, and the movable iron core (6) is improved. Therefore, the movable iron core (6) is easily attracted to the fixed iron core (2).

In addition, since the outer circumferential surface of the movable iron core (6) has no grooves (20) as shown in FIG. This resin coating will not be damaged even if the frictional resistance is reduced by applying (of course also to the bearing bushing (25)). The boundary parts damage the resin coating and cause it to peel off.

[Effect of the invention 1 As described above, according to the present invention, the bearing sleeve that guides the movable core (6) at the outer circumference with respect to the case (1) is shortened, and on the other hand, the movable core (6) is provided with a non-magnetic center rod (25), and the fixed iron core (
2), so the bearing bushing (2) is also guided.
7) can be made of magnetic material, and the case (1) and movable iron core (6
), the magnetic efficiency of the coil (4) is improved, and the coil (4) can be made smaller, which in turn allows the hydraulic control electromagnetic solenoid to be made smaller.

[Brief explanation of the drawing]

FIG. 1(a) is a longitudinal cross-sectional view of an electromagnetic solenoid for hydraulic control according to the present invention, the upper half of which shows the de-energized state of the solenoid coil, and the lower half of which shows the energized state of the solenoid coil. The diagram shown in FIG. 1(b) is similar to FIG. 1(a).
FIG. 2 is a cross-sectional view taken along line BB of FIG. 2(a) is a longitudinal cross-sectional view of a conventional electromagnetic solenoid for hydraulic control, the upper half of which shows the state when the solenoid coil is deenergized, and the lower half of which shows the state when it is energized. . FIG. 2(b) is a cross-sectional view taken along line A-A in FIG. 2(a). FIG. 3 is a longitudinal sectional view of another conventional electromagnetic solenoid for hydraulic control. FIG. 4 is a sectional view showing still another conventional electromagnetic solenoid for hydraulic control and a hydraulic control valve provided with the solenoid. In the figure, (1) is the case, (2) is the fixed core, and (3) is the case.
) is the end member, (4) is the coil, (5) is the winding frame, (6) is the movable core, (17) is the output shaft, (14) is the return spring, (
17a) is an axial passage, (24) is a radial passage, (
26) is a bearing bushing, and (27) is a magnetic bearing bushing. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A case with an end member fixed to the other end to form a yoke for the magnetic path, a solenoid coil housed in the case, a fixed iron core provided at the center of the other end of the case, and the fixed iron core. a movable core slidably provided to the case so as to face each other; an output shaft made of a non-magnetic material passing through the movable core and fixed thereto and protruding from one end of the case; the movable core and the fixed core; In the hydraulic control electromagnetic solenoid, the electromagnetic solenoid for hydraulic control is provided with a return spring provided in an opposing gap formed at a portion facing the movable iron core, and a passage device that communicates the opposing gap with a portion on the opposite side of the movable iron core. The outer periphery of the movable core is pivotally supported in the case via a magnetic bearing, and a non-magnetic center rod is provided on the movable core on the side facing the opposing gap, and this center rod is connected to the fixed core. An electromagnetic solenoid for hydraulic control, characterized by being pivotally supported via a bearing.