JP2020183784A - Hydraulic device - Google Patents

Abstract

To provide a hydraulic device which reduces a sliding resistance caused by movement of a component and improves detection accuracy of abnormality.SOLUTION: A hydraulic device provided with a solenoid valve 118 with a spool position detector which is arranged on an oil passage and controls a flow of hydraulic oil and an abnormality detector which detects abnormality of the solenoid valve, includes a movable core 150 which moves for a main body 134 of the solenoid valve by excitation of a solenoid coil 130, a rod 154 integrally fixed to the movable core, a spool 132 which is pressed by the rod and is moved and, thereby, controls a flow of hydraulic oil and ball bushes 156a, 156b which are fixed to the main body and slidably support the rod. Therein, a gap is formed between a lateral surface with respect to a movement direction of the rod and the movable core and the main body.SELECTED DRAWING: Figure 2

Description

The present invention relates to a hydraulic device provided with an abnormality detecting device for detecting an abnormality of a solenoid valve, and more particularly to a hydraulic device provided with an electromagnetic valve having a spool position detector capable of detecting the position of a spool of the solenoid valve.

A hydraulic device used in an industrial machine or a construction machine is a device that supplies hydraulic oil to a processing master machine having an actuator such as a cylinder or a hydraulic motor. Here, as the direction control valve of the hydraulic system, a spool-type solenoid valve that switches the direction in which hydraulic oil flows by moving the spool, which is a valve body, is widely used. In this solenoid valve, the movable iron core inside the main body is moved by the attractive force generated by the excitation of the electromagnetic coil, and the movement of the movable iron core is transmitted to the spool to move the spool. A rod held by a solenoid guide was interposed between the movable iron core and the spool as a transmission means.

Further, in the conventional hydraulic system, an abnormality detection device for early detection of an abnormality of the hydraulic system such as contamination of hydraulic oil has been used. As a technique for detecting an abnormality in such a conventional hydraulic system, Patent Document 1 describes a solenoid valve with a spool position detector in an oil passage, monitors a response time related to spool movement, and determines the response time. An abnormality detection device that detects the presence or absence of an abnormality by comparing and determining the value with the value is disclosed.

Japanese Unexamined Patent Publication No. 2016-31086

When the solenoid valve is switched in the abnormality detection device of the conventional hydraulic system, the movable iron core slides with respect to the main body of the solenoid valve, and the rod also slides with respect to the main body of the solenoid valve. The response time was affected by these sliding resistances, and even when the hydraulic system was in a normal state, the response time sometimes varied widely. Therefore, in the determination based on the response time, there is a possibility that an abnormality may be erroneously detected or an abnormality may be overlooked.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a hydraulic device that reduces sliding resistance caused by movement of parts other than spools and improves abnormality detection accuracy. To do.

The hydraulic device according to the present invention is a hydraulic device including a solenoid valve with a spool position detector that is arranged in an oil passage and switches the flow direction of hydraulic oil, and an abnormality detection device that detects an abnormality in the solenoid valve. ,
The solenoid valve is
With an electromagnetic coil
A movable iron core that moves with respect to the main body of the solenoid valve by excitation of the solenoid coil,
A rod that is integrally fixed to the movable iron core,
A spool that switches the direction in which hydraulic oil flows by being pressed by the rod and moving.
A ball bush that is fixed to the main body and slidably supports the rod,
A position detector for detecting whether or not the spool is in a predetermined position is provided.
The abnormality detection device is
A monitoring unit that is connected to the position detector and acquires the response time required for the spool to move in a predetermined section.
A determination unit for determining whether or not a predetermined response time or a predetermined calculated value calculated based on the response time exceeds a predetermined threshold value is provided.
A gap is formed between the side surface of the rod and the movable iron core in the moving direction and the main body.

According to the hydraulic system of the present invention, by reducing the sliding resistance generated by the movement of the movable iron core and the rod, the variation in the response time of the spool can be reduced and the accuracy of abnormality detection can be improved.

It is a schematic block diagram which showed the hydraulic system which concerns on 1st Embodiment of this invention. It is a figure which showed the solenoid valve with the spool position detector of the same hydraulic system. It is an enlarged view of the part A in FIG. It is a figure which showed the solenoid valve with the spool position detector of the same hydraulic system. It is an enlarged view of the part B in FIG. It is a figure which showed the response waveform of the solenoid valve when the hydraulic cylinder of the hydraulic system was driven. It is a block diagram which shows the internal structure of the abnormality detection device of the hydraulic system. It is a flowchart which shows the process performed by the abnormality detection device of the hydraulic system.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in such an embodiment are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are designated by the same reference numerals to omit duplicate description, and elements not directly related to the present invention are illustrated or described. Is omitted.

FIG. 1 is a schematic configuration diagram showing a hydraulic device 100 according to a first embodiment of the present invention. The hydraulic device 100 is a device that transmits power to an external processing master machine 102 using hydraulic oil flowing through the oil passage 106 as a medium. The oil passage 106 starts from a hydraulic source 108 including a hydraulic pump for delivering hydraulic oil from the tank 120 and is connected to the machining master machine 102, and drives the machining master machine 102 by the pressure of the hydraulic oil.

The processing master machine 102 includes a hydraulic cylinder 110 as an example of a hydraulically driven actuator.

In the hydraulic device 100, the solenoid valve 118, which is a solenoid valve with a spool position detector arranged in the path from the hydraulic source 108 to the processing base machine 102, is a valve for switching the flow direction of hydraulic oil. The motor 112 drives the hydraulic source 108. The check valve 114 is a valve that prevents the backflow of hydraulic oil. The relief valve 116 is a valve that controls the maximum pressure of the entire oil passage 106. The filter 122 removes foreign matter from the hydraulic oil.

The hydraulic device 100 includes an abnormality detecting device 104 that detects an abnormality of the hydraulic device such as contamination of hydraulic oil. The abnormality detection device 104 is electrically connected to the solenoid valve 118, and notifies the user of the occurrence of an abnormality based on the operation of the solenoid valve 118. In the following, the operation of the solenoid valve 118 will be described in detail prior to the specific operation of the abnormality detection device 104.

2 and 4 are views showing a solenoid valve 118 with a spool position detector. The solenoid valve 118 is a spool-type oil-immersed two-position solenoid valve provided with an electromagnetic coil 130 near one end. FIG. 2 shows a state in which the spool 132 is in the position on the left side of the paper in FIG. 2 in its movable range, and FIG. 4 shows the position of the spool 132 on the right side of the paper in FIG. 4 from the position on the left side. Shows the state of moving to. Hereinafter, the constituent members of the solenoid valve 118 that do not move when the spool 132 moves are collectively referred to as the main body 134, but the ball bushes 156a and 156b described later are not included in the main body 134.

The main body 134 of the solenoid valve 118 is provided with a plurality of ports (supply port 136, load ports 138a, 138b, tank ports 140a, 140b) connected to various parts of the oil passage 106 (see FIG. 1). The central supply port 136 is connected to the hydraulic pressure source 108, and the load ports 138a and 138b on both sides thereof are connected to the processing master machine 102. Further, tank ports 140a and 140b connected to the tank 120 are provided on both ends. The spool 132 is provided with lands 142a and 142b that cut off the connection of each port, and the spool 132 moves between the left side position and the right side position with respect to the paper surface in FIG. 2 to connect the ports. Is switched, and the path through which the hydraulic oil flows is switched.

On the left side of the spool 132, the fixed iron core 152 and the movable iron core 150 are arranged side by side in order from the side closer to the spool 132.

The movable iron core 150 is formed in a substantially cylindrical shape, and is arranged inside the electromagnetic coil 130 so as to be close to and separated from the fixed iron core 152. By energizing the solenoid coil 130, the movable core 150 is attracted to the fixed core 152 and moves to the right with respect to the main body 134 of the solenoid valve 118 toward the paper surface in FIG. As shown in FIG. 5, since the ring-shaped spacer 158 is arranged on the end face of the fixed core 152 on the movable core 150 side, the movable core 150 is fixed to the movable core 150 even when it is closest to the fixed core 152. A gap is provided between the iron core 152 and the iron core 152.

The rod 154 is a rod-shaped member that penetrates the inside of the movable iron core 150 in the left-right direction toward the paper surface in FIG. 2, and is integrally fixed to the movable iron core 150. The end of the rod 154 on the spool 132 side is in contact with the spool 132, and when the electromagnetic coil 130 is energized, it moves to the right together with the movable iron core 150 and presses the spool 132.

As shown in FIGS. 2 and 3, the rod 154 is inserted into a pair of ball bushes 156a and 156b arranged so as to sandwich the movable iron core 150 on the left and right, and is slidably supported by the ball bushes 156a and 156b. There is. The ball bushes 156a and 156b have a large number of balls inside a substantially cylindrical cage, and these balls contact and support the rod 154, and utilize the rolling of the balls to make the rod with a slight sliding resistance. The 154 can be slid in the left-right direction toward the paper surface in FIG. The ball bushes 156a and 156b are fixed to the main body 134 of the solenoid valve 118. The ball bush 156a provided between the movable iron core 150 and the spool 132 is arranged inside the fixed iron core 152.

As shown in FIGS. 2 and 4, a gap is provided between the outer peripheral surface, which is a side surface of the rod 154 with respect to the moving direction, and the main body 134. Therefore, the rod 154 slides only with the ball bushes 156a and 156b, and does not slide with the other members of the solenoid valve 118.

Further, as shown in FIGS. 3 and 5, a gap S is also provided between the outer peripheral surface, which is a side surface of the movable iron core 150 with respect to the moving direction, and the main body 134. Therefore, the movable iron core 150 does not slide with other members of the solenoid valve 118.

When the spool 132 is in the left position as shown in FIG. 2, the electromagnetic coil 130 is not energized and is in a non-excited state. At this time, the spool 132 is arranged at a position on the left side by being pushed from the right by a spring 143 provided near the right end. At this time, the supply port 136 and the load port 138a are connected, and the load port 138b and the tank port 140b are connected to supply hydraulic oil to the processing base machine 102.

When the electromagnetic coil 130 is excited from the state of FIG. 2, the movable iron core 150 inserted in the electromagnetic coil 130 is attracted to the fixed iron core 152 and moves to the right, and the rod integrally fixed to the movable iron core 150. 154 presses the spool 132, and the spool 132 moves to the right while compressing the spring 143. At this time, as shown in FIGS. 3 and 5, the rod 154 and the movable iron core 150 do not slide with the members other than the ball bushes 156a and 156b, so that the sliding resistance is extremely small. When the spool 132 moves to the right position as shown in FIG. 4, the supply port 136 and the load port 138b are connected, the load port 138a and the tank port 140a are connected, and hydraulic oil is supplied to the processing base machine 102. ..

The solenoid valve 118 of the present embodiment has a function of a position detector for detecting the position of the spool 132, and can electrically detect the position of the spool 132 from the outside. The position detector includes a ring 144 and a retainer 146 as components.

The position detector of the solenoid valve 118 has a so-called switch type structure. Specifically, the main body 134 is provided with a ring 144 which is a fixed contact, and a retainer 146 which is a movable contact is provided on the outer circumference of the spool 132. The retainer 146 is arranged on the right side of the ring 144 with respect to the paper surface of FIG. 2, and is urged to the ring 144 side by the spring 148. The retainer 146 moves with the spool 132, but is not completely fixed to the spool 132.

The ring 144 is electrically connected to a ring-side electric terminal (not shown). Since the retainer 146 is electrically connected to the housing and the retainer-side electric terminal (not shown) is also electrically connected to the housing, the retainer 146 is electrically connected to the retainer-side electric terminal. As shown in FIG. 2, when the spool 132 is in the left position, the ring 144 and the retainer 146 are in contact with each other, so that the ring-side electric terminal and the retainer-side electric terminal are electrically connected to each other. On the other hand, when the spool 132 is moved to the right position as shown in FIG. 4, since the retainer 146 is separated from the ring 144 as the spool 132 moves, the ring-side electric terminal and the retainer-side electric terminal are electrically connected. Not done.

Therefore, when the ring-side electric terminal and the retainer-side electric terminal are conducting, it can be seen that the spool 132 is in the left position as shown in FIG. Further, when the ring-side electric terminal and the retainer-side electric terminal are not conducting, it can be seen that the spool 132 is in a state of being moved to the right position as shown in FIG.

FIG. 6 is a diagram showing a response waveform of the solenoid valve 118 when the hydraulic cylinder 110 (see FIG. 1) is driven. In FIG. 6, the graph of "pressure" shows the passage of time in the right direction and the magnitude of the pressure of the hydraulic cylinder 110 in the vertical direction. The graph of "monitoring switch signal voltage" shows the passage of time in the right direction, and shows the magnitude of the voltage of the signal indicating the conduction state between the ring-side electric terminal and the retainer-side electric terminal in the vertical direction. The graph of "voltage of solenoid energization signal" shows the passage of time in the right direction, and shows the magnitude of the voltage of the energization signal when energizing the electromagnetic coil 130 in the vertical direction.

FIG. 6 also shows the time difference of the change of each waveform represented by the symbol T. These time differences represent the response times of the operations of the solenoid valve 118 and the hydraulic cylinder 110. For example, the time difference T1 is the response time from when the energization of the electromagnetic coil 130 (see FIG. 2) is turned on until the spool 132 is switched and the hydraulic oil starts to flow from the supply port 136 to the load port 138b. The time difference T2 is the response time from when the energization of the electromagnetic coil 130 is turned off until the spool 132 is switched and the hydraulic oil starts to flow from the supply port 136 to the load port 138a. The time difference T3 is a response time from when the energization of the electromagnetic coil 130 is turned on to when the ring-side electric terminal and the retainer-side electric terminal are turned off. The time difference T4 is a response time from when the energization of the electromagnetic coil 130 is turned off to when the ring-side electric terminal and the retainer-side electric terminal are turned on again.

As described above, the solenoid valve 118 with the spool position detector can electrically detect the response time of the operation of the spool 132. The above-mentioned abnormality detection device 104 monitors the spool 132 by electrically connecting to the solenoid valve 118, and based on the response time of the spool 132, detects an abnormality in the oil passage equipment including the hydraulic device 100 and the processing base machine 102. To detect.

Next, the internal configuration of the abnormality detection device 104 will be described. FIG. 7 is a block diagram showing an internal configuration of the abnormality detection device 104. The abnormality detection device 104 includes a setting unit 500, a signal input unit 502, a monitoring unit 504, a determination unit 506, and a notification unit 508.

The setting unit 500 sets a threshold value Tth for determining an abnormality and transmits it to the determination unit 506. This threshold value Tth is data set or input in advance to the program by the engineer, and serves as a reference for detecting an abnormality in the response time of the spool 132. The response time of the spool 132 is based on, for example, the time difference T3 from the change (ON) of the solenoid energization signal to the change (OFF) of the monitoring switch signal described with reference to FIG. However, the time difference T4 may be used instead of the time difference T3.

The signal input unit 502 acquires a solenoid energization signal when energizing the electromagnetic coil 130. Further, the signal input unit 502 acquires a monitoring switch signal indicating a conduction state between the ring-side electric terminal and the retainer-side electric terminal. The solenoid energization signal and the monitoring switch signal are sent to the monitoring unit 504.

The monitoring unit 504 detects the response time t of the spool 132 from the solenoid energization signal and the monitoring switch signal received from the signal input unit 502, and transmits the response time t to the determination unit 506. Although the time difference T3 is used as the response time t, the time difference T4 may be used.

The determination unit 506 determines whether or not the response time t received from the monitoring unit 504 exceeds the threshold value Tth received from the setting unit 500, and transmits the determination result to the notification unit 508.

The notification unit 508 outputs a notification to the user based on the determination result received from the determination unit 506.

The details of the processing of the abnormality detection device 104 will be described below. FIG. 8 is a flowchart showing the processing performed by the abnormality detection device 104.

First, in step S600, the setting unit 500 sets the threshold value Tth for determining the standard deviation of the response time of the spool 132.

Next, in step S602, the monitoring unit 504 acquires the response time t of the spool 132 through the signal input unit 502.

Then, in step S604, the determination unit 506 determines whether or not the response time t is equal to or less than the threshold value Tth (t ≦ Tth). When the response time t is equal to or less than the threshold value Tth (YES in step S604), the hydraulic device 100 and the like are normal, and the process proceeds to step S606. On the other hand, when the response time t exceeds the threshold value Tth (NO in step S604), the state of the hydraulic device 100 and the like is abnormal, and the process proceeds to step S608.

In step S606, the notification unit 508 lights a green lamp to notify the user that it is normal. Then, the process proceeds to step S602 to continue the process.

On the other hand, in step S608, the notification unit 508 lights a red lamp to notify the user of the abnormality, and ends the process.

In the hydraulic device 100 of the present embodiment, the rod 154 is slidably supported by the ball bushes 156a and 156b, and a gap is formed between the side surface of the rod 154 and the movable iron core 150 in the moving direction and the main body 134. Since the sliding resistance of the movable iron core 150 and the rod 154 can be reduced and the variation in the response time of the spool 132 due to the sliding resistance can be prevented, the accuracy of abnormality detection can be improved.

In the hydraulic device 100 of the present embodiment, the rod 154 is slidably supported by the ball bushes 156a and 156b, but instead of the ball bush, the rod is slidable by a guide or a metal bush using another rolling element. It may be supported as much as possible. Also in this case, since the rod and the movable iron core do not slide with the member other than the guide or the metal bush, the sliding resistance can be reduced and the accuracy of abnormality detection can be improved.

The abnormality detection device 104 of the present embodiment determines the abnormality by comparing the response time t with the threshold value Tth, but instead of this, a predetermined calculated value calculated based on the response time t is used. , The abnormality may be determined by comparing with the threshold value corresponding to this calculated value. Examples of the calculated value include, but are not limited to, a standard deviation of a plurality of response times t and a corrected response time obtained by adding a correction value corresponding to the oil temperature at the time of measurement to the response time t. In this case, a calculation unit is provided that receives the response time t from the monitoring unit 504, calculates the calculated value based on the response time t, and transmits the calculated value to the determination unit 506. By determining the abnormality using such a calculated value, the accuracy of detection can be further improved.

Further, in the present embodiment, the switch-type spool position detectors referred to in FIGS. 2 and 4 are provided, but other position detectors can be used instead. Other examples of the spool position detector include a differential transformer type and a magnetic switch type. In the differential transformer type, three coils are installed around the movable iron core linked with the spool, and by utilizing the difference in the induced voltage of the coils at both ends, the position and response time of the spool are electrically determined via the movable iron core. Can be detected. In the magnetic switch type, the position and response time of the spool can be electrically detected by using a magnet linked to the spool and a magnetic detection element fixed to the body. According to the configuration of the present embodiment using the movable iron core 150, the rod 154, and the ball bushes 156a and 156b, the sliding resistance is reduced and the accuracy of abnormality detection is improved regardless of the type of spool position detector. Can be improved.

100 Hydraulic device 102 Machining base machine 104 Abnormality detection device 106 Oil passage 108 Hydraulic source 110 Hydraulic cylinder 112 Motor 114 Check valve 116 Relief valve 118 Solenoid valve 120 Tank 122 Filter 130 Electromagnetic coil 132 Spool 134 Main body 136 Supply port 138a, 138b Load port 140a , 140b Tank port 142a, 142b Land 143 Spring 144 Ring 146 Retainer 148 Spring 150 Movable core 152 Fixed core 154 Rod 156a, 156b Ball bush 158 Spacer 500 Setting unit 502 Signal input unit 504 Monitoring unit 506 Notification unit 508

Claims (1)

A hydraulic device including a solenoid valve with a spool position detector that is arranged in an oil passage and switches the flow direction of hydraulic oil, and an abnormality detection device that detects an abnormality in the solenoid valve.
The solenoid valve is
With an electromagnetic coil
A movable iron core that moves with respect to the main body of the solenoid valve by excitation of the solenoid coil,
A rod that is integrally fixed to the movable iron core,
A spool that switches the direction in which hydraulic oil flows by being pressed by the rod and moving.
A ball bush that is fixed to the main body and slidably supports the rod,
A position detector for detecting whether or not the spool is in a predetermined position is provided.
The abnormality detection device is
A monitoring unit that is connected to the position detector and acquires the response time required for the spool to move in a predetermined section.
A determination unit for determining whether or not a predetermined response time or a predetermined calculated value calculated based on the response time exceeds a predetermined threshold value is provided.
A hydraulic device characterized in that a gap is formed between a side surface of the rod and the movable iron core in a moving direction and the main body.

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