JP2005111444A - Washing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new method for effectively washing a workpiece having an intricate internal cavity. <P>SOLUTION: At least one of openings 32-40 of the workpiece 30 having the internal cavity 31 is used as an inlet and at least one of the other openings as an outlet. A washing liquid 16 is supplied through the inlet, and moved in the cavity 31 while turbulance is generated in the liquid 16, and discharged through the outlet. The flow rate at the largest cross section area part of the cavity is set at Rec×ν×S/(4×d) or higher, provided, however, that Rec: Rey Number; V: the flow rate; ν: kinematic viscosity of the washing fluid; d: the cross section area; S: the length around the cross section. The washing liquid is supplied through liquid supplying nozzles 11a-13 attachably and detachably stuck on the openings with a pump 22 for pressure-feeding the washing liquid to the liquid supplying nozzles. The liquid supplying operation of the liquid supplying nozzles is selectively actuated with nozzle selection means 24a-24c. Thereby, the turbulent washing water effectively moves a foreign substance in the cavity and removes the same from the workpiece. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cleaning method effective for removing foreign matter of a workpiece having an internal cavity having a complicated shape, such as a cylinder block, a water jacket, etc., as well as a cylinder head constituting an internal combustion engine.

A workpiece such as a cylinder head, a cylinder block, or a water jacket has a cavity having a complicated shape in its structure. In manufacturing these workpieces, there is a problem that foreign matters such as chips generated by cutting remain, and conventionally, an operation of cleaning the inside of a cavity with a cleaning liquid has been performed.
Generally, methods for cleaning a workpiece include methods such as shower cleaning, ultrasonic cleaning, immersion rocking cleaning, underwater high pressure cleaning (for example, see Patent Document 1), and high pressure jet cleaning (for example, see Patent Document 2). ing. The above-described underwater high-pressure cleaning and high-pressure jet cleaning methods are generally employed for a workpiece having an internal cavity with a complicated shape such as a cylinder head.

In the underwater high-pressure cleaning, the cleaning device includes a cleaning tank, a nozzle, a high-pressure pump, a cleaning liquid processing device, and the like. In the cleaning operation, the cleaning tank is filled with the cleaning liquid, the workpiece to be cleaned is carried into the tank, and then the high-pressure cleaning liquid is ejected from the nozzle to move the nozzle and the workpiece relative to each other. After the cleaning is completed, the workpiece is carried out from the cleaning tank, and the cleaning liquid is subjected to a foreign matter separation process by a cleaning liquid processing apparatus. In Patent Literature 1, cavitation is generated by devising the shape of the injection nozzle to enhance the injection effect.
The high pressure jet cleaning method is a method of injecting high pressure cleaning liquid into the cavity through an opening communicating with the internal cavity of the workpiece. In Patent Document 2, this high-pressure jet cleaning method is adopted, and the cleaning effect is enhanced by applying pulsation or shock waves to the cleaning liquid.

JP-A-60-168554 JP 2000-157939 A

However, the above-described underwater high-pressure cleaning method has a problem in that a foreign substance is likely to be caught in a place where the cross-sectional area of the internal cavity changes from a large part to a small part, and a sufficient cleaning effect cannot be obtained. Further, as in Patent Document 1, there is a method of giving the effect of cavitation bubbles by making the nozzle a divergent horn shape. This cavitation bubble is effective against fine foreign matters, but is relatively free from chips and the like. There is a problem that it is not effective for large foreign objects. Furthermore, in the case of a workpiece having a complicated internal cavity, there is a problem in that a flow that effectively cleans an intricate shape cannot be formed because the high-pressure jet from the nozzle hits the wall surface of the workpiece and rebounds. Thus, there are a number of problems to be solved in the method of underwater high-pressure washing.
On the other hand, in the latter method using a high-pressure jet, a sufficient cleaning effect may not be obtained depending on the shape of the workpiece. In Patent Document 2, pulsation or the like is given to the jet flow of the cleaning liquid to enhance the effect of removing foreign matter, but still a sufficient cleaning effect has not been obtained.

  The present invention has been made based on the above circumstances, and has been completed based on the knowledge that the cleaning effect can be improved by causing turbulent flow in the cleaning liquid. That is, an object of the present invention is to provide a novel cleaning method having a high cleaning effect even for a workpiece having an internal cavity having a complicated shape.

That is, in order to solve the above-described problems, the invention according to claim 1 of the cleaning method of the present invention has a cavity inside, and the cavity is communicated to the outside through a plurality of openings. In the method
Using at least one of the openings as an inlet and at least one other as an outlet, cleaning liquid is supplied from the inlet, and the cleaning liquid is moved while generating turbulent flow in the cavity to discharge the outlet. It is characterized by discharging from the outlet.

According to a second aspect of the present invention, there is provided a cleaning method according to claim 2, wherein at least one of the openings is provided as an inflow port when cleaning a workpiece having a cavity inside and the cavity communicates with the outside through a plurality of openings. In the cleaning method of supplying the cleaning liquid from the injection port, using the other at least one as the discharge port, and moving the cleaning liquid in the cavity and discharging it from the discharge port.
The cleaning liquid is supplied to the inlet so that the cleaning water moves at a flow velocity V that satisfies the following formula (1) at the maximum cross-sectional area of the cavity.
V = Rec · ν · S / (4 · d) (1)
Where Rec: Reynolds number, V: flow velocity, ν: kinematic viscosity of fluid, d: cross-sectional area, S: perimeter of cross-section

  According to a third aspect of the present invention, there is provided a cleaning method according to the first or second aspect, wherein the cleaning is performed while switching the inlet for injecting the cleaning liquid and the outlet for discharging the cleaning liquid to another opening. It is characterized by.

  The invention of the cleaning method according to claim 4 is the invention according to any one of claims 1 to 3, wherein the opening having a small cross-sectional area is first used as an injection port for injecting the cleaning liquid, and thereafter the opening having a large cross-sectional area. Is the inlet.

  According to a fifth aspect of the present invention, there is provided a cleaning method according to any one of the first to fourth aspects, wherein air is injected and mixed into the cleaning liquid.

  That is, according to the present invention, since the cleaning liquid injected into the cavity moves while generating turbulent flow, the foreign matter can be reliably removed from the cavity wall and taken out together with the cleaning liquid. In particular, the cleaning liquid is supplied so that the cleaning water moves at a flow velocity V that satisfies the above equation (1) at the maximum cross-sectional area of the cavity, so that all the cavities are not attenuated in the cavity. In this region, turbulent flow can be reliably generated, and the cleaning effect can be sufficiently increased.

  In addition, the flow of the cleaning liquid is changed by switching the injection port and the discharge port to different openings during cleaning, so that foreign substances can be removed and discharged more reliably. In particular, if the cleaning solution is supplied from an opening with a small cross-sectional area at the beginning of the cleaning operation, such as when the internal contaminant is relatively large compared to the internal flow path, the foreign matter can be prevented from staying in the narrow opening. Cleaning can be performed particularly effectively for complex workpieces with internal cavities. Moreover, after that, by switching the supply destination to an opening having a large opening area, it is possible to reliably perform the cleaning including the opening having a small cross-sectional area.

  In addition, by mixing air with the high-flow-rate cleaning liquid supplied from the inlet, the water bubbles generated in the cleaning liquid will come into contact with foreign objects, and it is possible to reliably move foreign objects that are difficult to move with the cleaning water alone. become.

  The present invention can be suitably applied to a workpiece having an internal cavity having a complicated shape, such as a cylinder head constituting an internal combustion engine, a cylinder block, a water jacket, etc. It is not limited to a specific one, and can be widely applied as long as it has a cavity having a plurality of openings inside.

  In addition, regarding the calculation formula (1) of the flow velocity that is referred to when supplying the cleaning liquid in the present invention, the critical Reynolds number can be obtained in advance by measuring the critical Reynolds number with a model of a workpiece to be applied. Further, it may be determined as a reference numerical value and applied. As the critical Reynolds number, for example, a numerical value of 4000 can be given as an example. Further, the maximum cross-sectional area portion used in the calculation of Expression (1) can be determined based on the cross-sectional area in the direction orthogonal to the main flow direction of the cleaning liquid.

  When injecting the cleaning liquid, if there is an opening other than the inlet and outlet, it is desirable to temporarily seal the opening. Moreover, injection | pouring of a washing | cleaning liquid may be performed continuously and may be performed intermittently.

When injecting the cleaning liquid, a plurality of liquid feeding nozzles that are detachably attached to the opening and capable of feeding the cleaning liquid into the cavity and a nozzle that performs the liquid feeding operation among the plurality of liquid feeding nozzles are selected. A cleaning device with possible nozzle selection means can be used. The cleaning liquid can be pumped to the liquid feeding nozzle by a pump provided in the apparatus, a pump of another apparatus, a pump provided in a factory, or the like. In this cleaning apparatus, the nozzle to be fed can be selected by having a plurality of nozzles and nozzle selection means. The nozzle selection means can be constituted by, for example, a valve provided between each nozzle and a pump, and a nozzle to be fed is selected by opening and closing each valve. In addition, you may have a control part which concentrates and controls the opening / closing operation | movement of a nozzle. Further, each nozzle may be provided with an actuator for performing an attaching / detaching operation to the opening, and the controller may control the attaching / detaching operation of each actuator in addition to the nozzle opening / closing control.
In addition, since each nozzle can feed the cleaning liquid in close contact with the opening, it is possible to avoid the splashing of the cleaning liquid by the cavity wall, and to efficiently supply the cleaning liquid into the cavity.

  As described above, according to the cleaning method of the present invention, when the cleaning liquid flows through the internal cavity of the workpiece, the cleaning water becomes a turbulent flow, and the foreign matter in the internal cavity is effectively moved and removed to the outside. be able to.

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 shows the configuration of a cleaning apparatus for carrying out the present invention. It consists of a cleaning tank 10 and a cleaning liquid processing apparatus 20. The cleaning tank 10 has a volume capable of accommodating the workpiece 30, and a plurality of contact nozzles 11 a, 11 b, 11 c, 12, 13 and a seal pad 14 (one is shown in the figure) with respect to the workpiece 30. It is configured so that it can be moved away and in close contact and saved (returned). The moving means is configured by using a cylinder 15 or the like serving as an actuator as shown in the seal pad 14. In the present invention, the actuator may be other linear moving means.

  The cleaning tank 16 is configured such that the cleaning liquid 16 accumulates at the bottom, and the cleaning liquid 16 collected through the discharge pipe 17 connected to the bottom can be recovered to the cleaning liquid processing apparatus 20.

  The cleaning liquid processing apparatus 20 can collect and store the cleaning liquid 16 and supply the cleaning liquid 16 to the cleaning tank 10. The cleaning liquid processing apparatus 20 is divided by a filter 21 that is partitioned in the vertical direction, and is opposite to the discharge pipe 17 with the filter 21 in between. A cleaning liquid supply pump 22 is installed on the side.

  The contact nozzles 11a, 11b, 11c, 12, and 13 are connected to the discharge port 23 of the cleaning liquid supply pump 22 through supply pipes 25 having a plurality of solenoid valves 24a, 24b, and 24c, respectively. The high-pressure cleaning liquid 16 can be supplied to the desired movable contact nozzles 11a, 11b, 11c, 12, and 13 by opening and closing 24a.

  Further, the supply pipe 25 of some of the plurality of contact nozzles 11a, 11b, 11c, 12, and 13 (contact nozzles 12 and 13 in the figure) was led from a high-pressure air source (not shown). The air supply pipes 26 and 26 are joined. The air supply pipe 26 is also provided with solenoid valves 27 and 27 so that the supply of high-pressure air can be opened and closed.

  When cleaning the workpiece 30, the workpiece 30 is accommodated and positioned in the cleaning tank 10. The workpiece 30 is formed with an internal cavity 31, and openings 32, 33, 34, 35, 36, 37, 38, 39, 40 having various opening areas are opened to the outside, and the internal cavity 31 is connected to the outside. Communicate. Therefore, considering the flow of the cleaning liquid in the internal cavity 31, the openings 32 to 40 are selected, and the plurality of contact nozzles 11a, 11b, 11c, 12, 13 and the seal pad 14 are brought into close contact with the selected opening. In the illustrated example, the contact nozzle 11 a is attached to the opening 34, the contact nozzle 11 b is attached to the opening 35, the contact nozzle 11 c is attached to the opening 36, the contact nozzle 12 is attached to the opening 32, and the contact nozzle 13 is attached to the opening 37. The seal pad 14 is in close contact with the opening 33.

  Next, the cleaning liquid supply pump 22 is operated, the solenoid valves 24a to 24c of the supply pipe 25 are opened, and the pressurized cleaning liquid 16 is ejected through the contact nozzles 11a, 11b, 11c, 12, and 13 and selected. The internal cavity 31 is cleaned by forming a flow of cleaning liquid at a high flow rate from the supply port toward the selected discharge port in the internal cavity 31.

Here, the shape of the internal cavity 31 and the arrangement of the inflow ports (openings) where the contact nozzles 11a, 11b, 11c, 12, and 13 are brought into close contact so that the flow rate of the cleaning liquid 16 flowing through the internal cavity is equal to or higher than the critical speed Vc. The supply pressure and supply amount of the cleaning liquid supply pump 22 are determined in consideration of the number and the arrangement and number of discharge ports (openings).
The critical flow velocity Vc is Vc = Rec · ν · S /, where Rec is the critical Reynolds number, d is the maximum cross-sectional area of the flow path through which the cleaning liquid flows, S is the perimeter of the cross section, and ν is the kinematic viscosity of the cleaning liquid. It is calculated by (4 · d). The required supply amount is obtained by the sum of products of the flow velocity Vi of the flow path obtained inside the cavity (i position) and the cross-sectional area di of the internal flow path based on the critical flow velocity Vc, that is, Σ (Vi * di). . Therefore, the cleaning liquid of the supply amount or more obtained by this calculation is discharged from the cleaning liquid supply pump 22.

The supply pressure of the cleaning liquid is determined as a pressure P that can ensure a flow rate equal to or higher than the critical flow rate Vc, and is obtained from a general formula that depends on the nozzle cross-sectional areas of the contact nozzles 11a, 11b, 11c, 12, and 13.
In this way, the cleaning liquid is caused to flow through the internal cavity 31 of the workpiece 30 at a flow rate equal to or higher than the critical flow rate Vc, so that a turbulent flow is formed in the cleaning liquid 16 and finally discharged together with the foreign matter through the selected discharge port.

In some cases, such as when the shape of the internal cavity 31 of the workpiece 30 is more complicated, foreign matter may remain in a part of the internal cavity 31. In such a case, if the solenoid valve 27 of the air supply pipe 26 connected to the high-pressure air source is opened so that a high-velocity air is mixed in the flow of the cleaning liquid 16 and the water bubble powder hits the foreign matter, the movement of the foreign matter is prevented. The cleaning effect due to the turbulent flow of the cleaning liquid can be increased.
The cleaning liquid 16 and foreign matter discharged from the internal cavity 31 of the workpiece 30 are separated by the filter 21 of the cleaning liquid processing apparatus 20, and the cleaning liquid 16 that has passed through the filter 21 is circulated to the cleaning liquid supply pump 22 again.
In the above embodiment, the cleaning liquid 16 may be supplied intermittently by opening / closing control of the solenoid valve 24 or the intermittent operation of the cleaning liquid supply pump 22.
In the above embodiment, the cleaning apparatus is described as including a pump. However, the cleaning liquid may be pumped by a pump other than the apparatus, for example, a pump included in a factory.

  Further, the inlet of the cleaning liquid 16 may be switched by changing the opening / closing timing of the solenoid valves 24 a to 24 c provided in the supply pipe 25. For example, in cleaning after the start of cleaning, an opening having a small opening area (cross-sectional area) is selected as an inflow port so that the cleaning liquid flows toward the opening having a large opening area. A large opening may be selected as the inlet so that the cleaning liquid flows toward the opening having a small opening area.

  FIG. 2 shows an example of the cleaning pattern. In the cleaning operation, the cleaning liquid is first ejected from the openings 32 and 37, and then the cleaning liquid is ejected from the openings 33, 34, 35, and 36. Next, the cleaning liquid is ejected from the opening 32, and then the cleaning liquid is ejected from the opening 37. In the opening where the cleaning liquid is not ejected, the contact nozzle is retracted (returned) so that the cleaning liquid can be discharged.

It is a block diagram of the washing | cleaning apparatus which implements this invention. Similarly, it is a figure which shows a washing | cleaning pattern.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cleaning tank 11a, 11b, 11c, 12, 13 Contact nozzle 14 Seal pad 15 Cylinder 16 Cleaning liquid 17 Discharge pipe 20 Cleaning liquid processing device 21 Filter 22 Cleaning liquid supply pump 23 Discharge port 24a Solenoid valve 24b Solenoid valve 24c Solenoid valve 25 Supply pipe 26 Air supply pipe 27 Solenoid valve 30 Workpiece 31 Cavity 32, 33, 34, 35, 36, 37, 38, 39, 40 Opening

Claims (5)

In a method for cleaning a workpiece having a cavity inside, the cavity communicating with the outside through a plurality of openings,
Using at least one of the openings as an inlet and at least one other as an outlet, cleaning liquid is supplied from the inlet, and the cleaning liquid is moved while generating turbulent flow in the cavity to discharge the outlet. A cleaning method characterized by discharging from the outlet. When cleaning a workpiece having a cavity inside, and the cavity communicates with the outside through a plurality of openings, at least one of the openings serves as an inlet, and at least one other serves as an outlet. In the cleaning method of supplying the cleaning liquid from the inlet, moving the cleaning liquid in the cavity and discharging it from the outlet,
A cleaning method, characterized in that the cleaning liquid is supplied to the inlet so that the cleaning water moves at a flow velocity V that satisfies the following formula (1) at the maximum cross-sectional area of the cavity.
V = Rec · ν · S / (4 · d) (1)
Where Rec: Reynolds number, V: flow velocity, ν: kinematic viscosity of fluid, d: cross-sectional area, S: perimeter of cross-section The cleaning method according to claim 1, wherein the cleaning is performed while switching the inlet for injecting the cleaning liquid and the outlet for discharging the cleaning liquid to another opening. The cleaning method according to any one of claims 1 to 3, wherein an opening having a small cross-sectional area is first used as an injection port for injecting a cleaning liquid, and thereafter an opening having a large cross-sectional area is used as the injection port. The cleaning method according to claim 1, wherein air is injected into and mixed with the cleaning liquid.

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