JPH034084A - Operation detecting structure for control valve - Google Patents

Abstract

PURPOSE:To contrive the smallness in size, saving of space and the improvement of efficiency of assembly work by providing an opening-closing switch, urged by moving a spool and electrically opened and closed, in a return spring housing part. CONSTITUTION:Lead plates 49A, 49B are provided in the groove of a barrel part in an insulating spring case 31B, a bottom side end part is connected to the first and second connection terminals 50A, 50B for penetrating through the bottom part of the folded case 31B and contact plates 45A, 45B are embedded in a seal plate 31Ba. While upper and lower side contact pieces 46U, 46L are buried in upper and lower side spring seats 38U, 38L, the upper side contact piece 46U is connected to the contact plates 45A, 45B and the lower side contact piece 46L is connected to the first and third connection terminals 50A, 50C but not connected to the second connection terminal 50B. Accordingly, in accordance with the position of a spool 37, the first connection terminal 50A as a common terminal is switched with the second and third connection terminals 50B, 50C to detect the position, and assembly workability can be improved by miniaturizing a control valve with the space saved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a control valve operation detection structure, and is particularly applicable to a switching valve used in an electric forklift or the like to control the flow direction of a working fluid. The present invention relates to a structure for electrically detecting an operation performed.

[Conventional technology]

Conventionally, as a control valve operation detection structure, a structure shown in FIGS. 10 and 11 is known. This is used, for example, in electric forklifts.

In FIG. 1O, l indicates a 4-boat, spring center type manual switching valve; the pump boat of this switching valve 1;
The tank boat has a hydraulic pump forming the fluid pressure source2. It is connected to a tank 3, and the two cylinder boats are connected to a double-acting cylinder 4 as an actuator. The hydraulic pump 2 is driven by an electric motor 5.

As is well known, the switching valve 1 has a spool 7 that moves through an insertion hole inside the valve housing IA to open and close each boat, and one end of the spool 7 is shown in FIG. 2(a). As shown in (C), it extends into a spring case IB attached to the lower end of the valve housing IA. As shown in the figure, two upper and lower spring seats 8U and 8L are attached to the end of the spool 7 in the spring case IB with mounting bolts 9.
U.

A return spring 10 is interposed between 8L.

In the figure, 11 is a case mounting bolt.

On the other hand, the other end of the spool 7 extends above the valve housing IA as shown in FIG. 1O, and a microswitch operating dog 12 is integrally formed in this extended portion. A roller plunger type microswitch 14 is disposed opposite to the dog 12 via a mounting bracket 13. The upper end of the dog 12, ie, the upper end of the spool 7, is connected to an operating lever 16 via a link mechanism 15.

Further, the motor 5. A motor drive circuit shown in FIG. 12 is formed between the microswitches 14. In other words,
Battery 18. Key switch 19゜Micro switch 1
4. and a relay 2 with normally open (N, O,) contacts 20A.
0 is formed, and the series circuit of the microswitch 14 and the relay 20 is connected in parallel with the series circuit of the relay contact 20A and the motor 5.

Therefore, assume that the key switch 19 is turned on.

When the lever I6 is not operated in this state, the microswitch 14 remains off and the relay 20 is not energized.
Therefore, the relay contact 20A also remains open (off), and the motor 5 is also stopped. In addition, the return spring 10 in the spring case IB is expanded (see FIG. 2(a)), and the spring force urges the spool 7 to a predetermined neutral position in the valve housing IA. It doesn't work.

When the lever 16 is operated in the direction A in FIG. 10 from this state, the spool 7 is pulled upward against the spring force of the spring 10 (see FIG. 11).
The dog 12 turns on the microswitch 14. Therefore, in the motor drive circuit shown in FIG. 12, the relay 20 is energized, the relay contact 2OA is closed, the motor 5 is rotated, and the hydraulic pump 2 is operated. At this time, in the switching valve 1, a flow path in a predetermined direction is formed as the spool 7 moves,
Oil is supplied from the hydraulic pump 2 to the cylinder 4, and the cylinder operates.On the contrary, when the lever 16 is operated in the direction B in FIG. 10, the spool 7 is pushed in against the spring force of the spring 10. (See FIG. 11(C)), and in the switching valve 1, a flow path is formed in the opposite direction to that described above. At this time, since the microswitch 14 is turned on by the downward movement of the dog 12, the hydraulic pump 5 is driven and the cylinder 4 is operated in the opposite direction.

In addition, in the above conventional example, the pulling operation of the spool 16 (
When the motor 5 is started only when the lever 16 is operated in six directions), the shape of the microswitch operating dog 12 may be as shown in FIG. 13. That is, in the dog 12 shown in the figure, a tapered surface is formed only on the lower side.

[Problem B to be Solved by the Invention] However, in the operation detection structure of such a switching valve, it is necessary to provide a dog for operating a microswitch on the spool of the switching valve, and a bracket for mounting the microswitch on the outside of the switching valve. Because it was essential to install a microswitch and to secure a space for installing a microswitch outside the switching valve, that is, inside the mounted machine, the overall structure became large, which went against the request for space saving. When the microswitch is mounted on a vehicle, etc., there are problems in that the efficiency of the assembly work is deteriorated and it becomes extremely difficult to adjust the gap between the roller of the microswitch and the spool dog.

This invention was made by focusing on the problems of the conventional operation detection structure, and aims to significantly downsize the entire operation detection structure, save space, and improve the efficiency of assembly work. The problem to be solved is to eliminate the need for adjustment of the operation of the switch mechanism after assembly.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a valve that controls the direction of working fluid flowing from a fluid pressure source to an actuator by moving a spool when operated, and which In the control valve, the control valve is provided with a spring accommodating portion that accommodates a return spring that returns the spool to a neutral position when the spool is moved.The spring accommodating portion is provided with an open/close switch that is electrically opened and closed by being biased by movement of the spool.

[Effect]

In the control valve of this invention, when no operating force is applied to the spool, the spool is biased by the return spring to take a predetermined neutral position, and when an operating force is applied to the spool, an offset corresponding to the direction of the action is applied. position, which causes actuating fluid from the fluid pressure source to flow through the control valve to the actuator, activating the actuator. In parallel with this, the opening/closing switch is opened and closed by the movement of the spool within the spring housing section. In other words, the opening/closing status of this on/off switch reflects the operation status of the control valve, so by connecting the drive circuit that drives the actuator to the terminal of this on/off switch, the movement of the spool,
That is, the drive circuit can be activated depending on the operating situation. Therefore, it is no longer necessary to provide a microswitch or the like which is activated by the movement of the spool outside the control valve as in the conventional case.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 7.

FIG. 1 is a diagram showing a state in which an electric forklift is implemented. In the figure, reference numeral 31 indicates a four-boat spring center type manual switching valve as a control valve, and the pump boat and tank boat of this switching valve 31 are hydraulic pumps 32 and 32 forming a fluid pressure source. It is connected to a tank 33, and the two cylinder boats are connected to a double-acting cylinder 34 as an actuator. The hydraulic pump 32 is driven by an electric motor 35.

The switching valve 31 is configured such that a spool 37 moves through an insertion hole inside the valve housing 31A to open and close each boat, and one end of the spool 37 is connected to the valve housing as shown in FIG. Attached to the lower end of 31A,
It extends into a substantially cylindrical spring case 31B made of an insulator such as synthetic resin.

The side of the spring case 31B that comes into contact with the valve housing 31A is covered with an insulating seal plate 31Ba that allows the spool 37 to pass through. Furthermore, two upper and lower spring seats 38U and 38L are attached to the end of the spool 37 extending into the substantially cylindrical interior of the spring case 31B with mounting bolts 39 as shown in the figure. A return spring 40 is interposed between them. In FIG. 1, 41 is a case mounting bolt. In this embodiment, the upper side and lower side in FIG. 1 are hereinafter referred to as "upper side" and "lower side."

The seal brake (31Ba) is formed in a substantially fan-like shape as shown in FIG. 3 in a predetermined area on the inner surface side symmetrical with respect to the central axis, and is made of a conductive material. 2nd contact play) 45A and 45B are buried. As shown in FIG. 1.4, an upper contact piece 46U formed in a ring shape and made of a conductive material is embedded in the position of the upper spring seat 38U that can come into contact with the contact plates 45A, 45B. . Similarly, a lower contact piece 46L formed in the same manner as the upper contact piece is embedded in the surface of the lower spring seat 38L that contacts the case bottom.

Furthermore, as shown in FIG. 5.6, the body of the spring case 31B has a first groove 4 having a predetermined depth and width from the inner peripheral surface side.
8A and a second groove 48B are bored in the longitudinal direction (in the axial direction of the case) from the inner peripheral surface side, and a first groove 48A and a second groove 48B formed of a conductor are formed in each groove 48A and 48B. Second lead plates 49A and 49B are provided. Each of the lead plates 49A and 49B is bent at a substantially right angle at a position where it abuts the bottom surface of the case 31B, and at this bending position, the bent portion becomes the first lead plate for wiring. It is connected to second connection terminals 50A and 50B.

Each of the terminals 50A and 50B penetrates and stands upright from the inside of the case to the outside. Similarly, a third connection terminal 50C for wiring is provided at the bottom of the case as shown in FIG. 4.6.

Here, the mounting positions of each of the terminals 50A to 50C are the positions that draw an isosceles triangle with the first connection terminal 50A as the apex, as shown in FIG. 2, when the spring case 31B is viewed from below (bottom side). However, since the head of the second branch terminal 50B is formed at a lower position than the other terminals 50A and 50C, it is actually in a position where it can abut on the lower contact piece 46L. The above-mentioned first and second grooves 48A and 48B are positioned accordingly.The first connection terminal 50A is set to the second and third connection terminals 50B and 50C. It functions as a common terminal.

Furthermore, the above-mentioned No. 1. The upper end portions of the second lead plates 49A and 49B are also slightly bent inward, and the upper end portions of the second lead plates 49A and 49B are bent inwardly, giving elasticity due to this bending. It is brought into contact with second contact plates 45A and 45B, respectively.

On the other hand, the other end of the spool 7 extends above the valve housing 31A as shown in FIG. .

Therefore, the spring case 31B in this embodiment
Inside are a first connection terminal (common terminal) 50A - a first lead plate 49A - a first contact plate 45A - an upper contact piece 46U -
A first opening/closing switch 56A is formed, which is a path passing through the second contact plate 458, second lead plate 49B, and second connection terminal 50B, and which uses the upper contact piece 46U as an opening/closing point. Connection VT terminal (both i11 terminal) 50
A - the lower contact piece 46L - the second meridian via the third connection terminal 50C, of which the lower contact piece 46L is the opening/closing point.
An open/close switch 56B is formed (see Fig. 7).
.

Further, the motor 35. 1st. Second open/close switch 5
A morph drive circuit shown in FIG. 7 is formed between 6A and 56B. In other words, battery 58° key switch 59.
A first on/off switch 56A, a second on/off switch 56B,
and a relay 60 having a normally closed (N, C,) contact 60A are sequentially connected, and the first open/close switch 56A to the relay 6
A series circuit consisting of a relay contact 60A and a motor 35 is connected in parallel to the series circuit of 0.

Next, the operation of this embodiment will be explained.

First, assume that the key switch 59 is turned on.

When the lever 53 is not operated in this state, no biasing force is applied to the return spring 40, so the upper and lower spring seats 38U and 38L move to their upper and lower limits, respectively, and the upper and lower contact pieces 46U, 46L is the 1st.
The second contact plates 45A, 45B and the first contact plate 45A, 45B. It is in contact with the third connection terminals 50A and 50C (see the state in Figure 1).
, Ml.

Both of the second open/close switches 56A and 56B are in the on state. Therefore, since a closed circuit passing through the battery 58 and the relay 60 is constructed, the relay 60 is energized and its contacts are opened (off), and the motor 5 maintains its stopped state with its power supply circuit cut off.

In this state, when the lever 53 is operated, for example, in the direction shown in FIG. 1, the spool 37 is pulled upward against the spring force of the spring 40 (same state as in FIG. 11(b)). The lower spring seat 38L is also pulled up by this force, so the lower contact piece 46L is moved to the first position.
．． It is separated from the third connection terminals 50A and 50C, and as a result, only the second on-off switch 56B is turned off while the first on-off switch 56A remains on. This de-energizes the relay 60, so its contact 60
A is closed (on), a power supply circuit for the motor 35 is formed, the motor 35 rotates, and the hydraulic pump 32 is operated.

At this time, a flow path in a predetermined direction is formed in the switching valve 31 as the spool 37 moves, oil is supplied from the hydraulic pump 32 to the cylinder 34, and the cylinder is operated to perform a predetermined work.

When the operation of the lever 53 in the A direction is stopped from this state, the second open/close switch 56B is turned back on, so the relay 60 becomes energized, its contact 60A is opened (off) again, and the rotation of the motor 35 is stopped. Stop. At the same time, since the switching flow path is cut off in the switching valve 31, the operation of the cylinder 34 is also stopped.

On the other hand, when the lever 53 is moved in the direction B in FIG. 1 from the above-mentioned stopped state, the spool 37 is pushed in against the spring force of the spring 40 (same state as in FIG. 11(C)).
, and the upper spring seat 38U is also pushed down, so that the upper contact piece 46U is pressed down to the first position. Second contact plate 45A.

45B, and eventually the first on-off switch 56A is turned off while the second on-off switch 56B remains on. As a result, the relay 60 becomes de-energized as described above, so its contact 60A is closed (on), the motor 35 rotates, and the hydraulic pump 32 is operated. At this time, the flow path is switched in the switching valve 31 as the spool 37 moves, which causes the cylinder to operate in the opposite direction.
You can make them do the specified work.

As described above, according to this embodiment, since there is no need for a microswitch or the like provided outside the switching valve, the switching valve is miniaturized, assembly is very easy, and failures caused by foreign objects are greatly reduced. Furthermore, there is no need to adjust the gap between the roller and the dog of the microswitch after assembly, which was seen in the conventional example, and maintenance becomes easier.

Next, other usage examples of the control valve operation detection structure according to the above embodiment are shown in FIGS. 8 and 9, respectively. In both figures, the same reference numerals are used for the same components as in the previous embodiment.

Of these, the circuit shown in FIG. 9 is a circuit that performs chopper control on the rotation speed of a pump motor 35 of an electric forklift. As shown in the figure, the first connection terminal 50A of the switching valve 31 connects to the battery 58 via the key switch 59, and
The second connection terminal 50B is connected to the battery 5 through a first relay 62 having a normally closed contact 62, and the third connection terminal 50C is connected to the battery 5 through a second relay 63 having a normally closed contact 63.
It reaches 8. The load side of the key switch 59 is connected to the motor 35. It is connected to the batch 1J58 via the chopper amplifier 64, and is also individually connected to the variable resistor 65.66, and the output ends of both resistors 65.66 are connected to the relay contact 62A.
, 63A individually to a phase shifter 67, and the output of this phase shifter 67 serves as a control input for the chopper amplifier.

Therefore, when the lever 53 is pulled in the direction A in FIG. 1 to pull up the spool 37 of the switching valve 31 (tilt backward operation), only the second open/close switch 56B opens (off), and the relay 63 is turned off, and the pump motor 35 rotates at the rotation speed set by the variable resistor 66. When the pump motor 35 is operated in the opposite direction to push the spool 37 into operation (tilt forward operation), only the first open/close switch 56A is turned off. is opened (off), the other relay 62 is turned off, and the pump motor 35 rotates at the rotation speed set by the variable resistor 65. In this manner, the rotational speed of the pump motor 35 can be controlled separately in the forward tilting and backward tilting operations. Thereby, the pump motor can be driven at different rotation speeds when tilting forward and when tilting backward, and energy saving can be easily achieved.

In other words, since the conventional operation detection structure is equipped with only one microswitch, there was a problem in that it was not possible to assemble a circuit as shown in FIG. 8, but with the present invention, it is possible to change the connection. The switching valve 31 can be easily assembled by itself, increasing the versatility of the switching valve 31 and improving the efficiency of the assembly work. In the conventional configuration shown in FIG. 10, if two microswitches that operate in opposite directions are provided, a circuit similar to that shown in FIG. This exacerbates the existing problems.

Furthermore, the one in Fig. 9 only operates when the operating lever 53 of the electric forklift is pulled (direction A in Fig. 1).
This is a circuit that drives the pump motor 35. This circuit is obtained by removing the first open/close switch 56A from the one in Fig. 7, and its operation is the same (when the spool 37 is pushed in, the motor stops).To assemble this circuit,
All it takes is a simple task of changing the connections of the terminals 50A to 50C.

Note that the operation detection structure according to the present invention does not necessarily require the first operation detection structure as described above. There is no need to provide the second two open/close switches, and either one may be used as required. In addition, air may be used as the working fluid instead of oil.

〔Effect of the invention〕

As explained above, an open/close switch that is electrically opened and closed by being biased by the movement of the spool is provided inside the spring housing, so it is placed outside the control valve and is activated by being biased by the spool of the control valve as in the past. It is no longer necessary to provide a micro switch and its support, which makes it possible to significantly downsize the entire operation detection structure, save space, and greatly improve the efficiency of assembly work, as well as reduce maintenance after assembly. This has the effect of significantly reducing the effort involved. Further, in the open/close switch of the present invention, since the contacts are pressed by the spool biasing spring, contact failures and the like do not occur.

[Brief explanation of the drawing]

1 to 6 are diagrams showing one embodiment of the present invention, in which FIG. 1 is an overall configuration diagram with a main part being a sectional view taken along line A-A in FIG. 2, and FIG. The figure is a bottom view of the switching valve in Figure 1,
Figure 3 is a cross-sectional view taken along the line C-C in Figure 1, Figure 4 is a cross-sectional view taken along the line B-B in Figure 2, and Figure 5 is a cross-sectional view taken along the line D-D in Figure 1. A cross-sectional view taken along the line, Figure 6 is E-E in Figure 1.
7 is a circuit diagram showing a pump motor drive circuit to which the above embodiment is applied, and FIGS. 8 and 9 are other examples of pump motor drive circuits using the above embodiment, respectively. 10 is an overall configuration diagram showing a conventional example, FIGS. 11(a) to (C) are sectional views showing the movement of the return spring in the conventional example in FIG. 10, and FIG. FIG. 13 is a circuit diagram showing a pump motor drive circuit according to a conventional example, and FIG. 13 is a side view showing another conventional example of a microswitch operating dog. In the figure, 31 is a switching valve as a control valve, 31.8 is a spring case as a spring housing part, 32 is a hydraulic pump, 33 is a tank, 34 is a cylinder as an actuator, 35 is an electric motor, 37 is a spool, 38U, 38
L is the upper 5 lower spring seat, 40 is the return spring, 50A to 50C are the first to third connection terminals, 56A
, 56B is the first opening/closing switch. This is a second open/close switch. ＾tC

Claims (1)

[Claims] (1) A valve that controls the direction of working fluid flowing from a fluid pressure source to an actuator by movement of a spool when operated, and includes a spring housing part that accommodates a return spring that returns the spool to a neutral position when not operated. An operation detection structure for a control valve, characterized in that an opening/closing switch that is electrically opened and closed by being biased by movement of the spool is provided in the spring housing part.