JP2006177451A - Slow return valve and hydraulic drive unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a slow return valve increasing the compatibility of a hydraulic drive unit for multiple purposes and excellent in usability also to general users. <P>SOLUTION: This slow return valve 8 is used in a hydraulic drive unit 10 independently providing a hydraulic drive force to a driven body and restricts the flow of a working fluid flowing out of a hydraulic actuator 2 generating the drive force. The restricted amount of the slow return valve is set selectively. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a slow return valve that is used in a hydraulic drive unit that independently applies a hydraulic drive force to a driven body, and that adjusts the flow rate of a working fluid that flows out of the hydraulic actuator that generates the drive force, and the slow return valve It is related with the hydraulic drive unit provided with.

  A hydraulic drive unit that easily provides hydraulic drive force as long as there is a power supply without using hydraulic piping is used, for example, for lifting and lowering work equipment with respect to the cultivated ground of special agricultural vehicles. The above application fields are expected and expanded.

  FIG. 11 is a hydraulic circuit diagram showing a basic configuration of the hydraulic drive unit.

  The hydraulic drive unit OU pumps the hydraulic oil in both forward and reverse directions by the forward / reverse rotating motor M in order to give the driven body W a hydraulic drive force independently while circulating the hydraulic oil in a closed system. A hydraulic pump OP, a hydraulic actuator OA (here, a hydraulic cylinder) that operates by the hydraulic oil and generates the driving force, a tank OT that stores hydraulic oil in a closed space, and between the hydraulic pump OP and the hydraulic actuator OA The operation check valve OC for controlling the forward / reverse bidirectional flow of the hydraulic oil and the switching valve OI for controlling the forward / reverse bidirectional hydraulic oil flow between the hydraulic pump OP and the tank OT are provided as basic components. Yes.

  The operating check valve OC basically pilots the hydraulic pressure to the check valve OCa to a pair of check valves OCa that allow only the flow of hydraulic oil from the hydraulic pump OP to the hydraulic actuator OA. And a pair of pilot lines OCb.

  The pair of check valves OCa includes a pipe line connecting one port of the hydraulic pump OP and the bottom side oil chamber OAa of the hydraulic actuator OA, the other port of the hydraulic pump OP and the rod side oil chamber OAb of the hydraulic actuator OA. And a pipe line connecting the two.

  The switching valve OI switches and connects between the tank OT and any pipe line between the hydraulic pump OP and the bottom side oil chamber OAa and the rod side oil chamber OAb of the hydraulic actuator OA.

  In the following description, the left side in the figure, such as the check valve OCa arranged in a pair of left and right, the one on the bottom side and the right side as the hydraulic oil entering and leaving the bottom side oil chamber OAa of the hydraulic actuator OA, The rod-side oil chamber OAb may be referred to as the rod side as it relates to the hydraulic oil entering and leaving the rod-side oil chamber OAb. Similarly, in the port of the hydraulic pump OP, the left side may be referred to as the bottom side and the right side may be referred to as the rod side.

  With such a configuration, according to the hydraulic drive unit OU, in a state where the hydraulic pump OP is stopped, the operation check valve OC allows any one of the bottom side oil chamber OAa and the rod side oil chamber OAb of the hydraulic actuator OA. The hydraulic oil is prevented from flowing out from the side, and the current stationary state of the hydraulic actuator OA is maintained against a predetermined external force.

  When the hydraulic pump OP rotates to discharge hydraulic oil to the bottom port, the hydraulic oil is supplied from the hydraulic pump OP to the bottom oil chamber OAa through the bottom check valve OCa, and at the same time, the bottom pilot line OCb The hydraulic oil that pushes and opens the rod side check valve OCa by the hydraulic pressure, allows the hydraulic oil to flow from the rod side oil chamber OAb to the hydraulic pump OP, and circulates clockwise between the hydraulic pump OP and the hydraulic actuator OA. And a driving force in the extending direction is generated in the hydraulic actuator OA.

  At this time, considering the case where the hydraulic actuator OA is a hydraulic cylinder as illustrated, the rod-side oil chamber OAb is compared to the amount of hydraulic oil flowing into the bottom-side oil chamber OAa with respect to the movement amount of the piston of the hydraulic cylinder. The amount of hydraulic oil flowing out from the piston is reduced by the amount of the rod of this piston, but the switching valve OI is pushed by the hydraulic oil on the bottom side of higher hydraulic pressure so that the switching valve OI is connected between the pipe line to the rod side oil chamber OAb and the tank OT. It switches so that they may be connected to each other, and a shortage of hydraulic oil is supplied from the tank OT.

  On the other hand, when the hydraulic pump OP rotates so as to discharge the hydraulic oil to the rod side port, the reverse flow of the hydraulic oil occurs, and a driving force in the contracting direction is generated in the hydraulic actuator OA, and the bottom side oil is generated. The hydraulic fluid flowing into the hydraulic pump OP from the chamber OAa becomes redundant, but the excess hydraulic fluid is connected to the tank OT and the pipe line to the bottom side oil chamber OAa by the action of the switching valve OI opposite to the above. , It is returned to the tank OT.

  Note that the amount of hydraulic oil in the sealed tank OT increases or decreases depending on the position of the piston of the hydraulic cylinder that is the hydraulic actuator OA, and the gas pressure sealed in the tank OT varies. Therefore, the fluctuation of the gas pressure does not affect the operation of the hydraulic drive unit OU.

  Thus, the function of the hydraulic drive unit OU is exhibited and maintained while using the hydraulic actuator OA which is a closed system and has a difference in the amount of hydraulic oil entering and exiting due to its operation.

  The hydraulic drive unit OU includes the following additional elements in addition to the basic components described above.

  In the pipelines between the bottom side oil chamber OAa of the hydraulic actuator OA, the rod side oil chamber OAb and the respective check valves OCa of the operating check valve OC, hydraulic oil from the respective oil chambers OAa, OAb to the check valve OCa is provided. Slow return valves SR for restricting only the flow are provided respectively.

  The slow return valve SR is for preventing hunting that occurs when an external force is generated from the driven body W during operation of the hydraulic pump OP.

  From the pipelines between the slow return valves SR and the check valves OCa, pipelines provided with relief valves RV1 respectively branch to the tank OT. Similarly, from the pipe line between the hydraulic pump OP and the check valve OCa on the bottom side and the rod side, pipe lines each provided with a relief valve RV2 branch to the tank OT.

  These relief valves RV1 and RV2 allow excess hydraulic oil to escape to the tank OT when an abnormal pressure occurs in the branch source pipe.

  Furthermore, from the pipe line between the rod side and bottom side slow return valve SR and the check valve OCa, the pipe line provided with the emergency manual valve MV branches to the tank OT, and the hydraulic pump OP is powered. When the emergency manual valve MV is used, the hydraulic actuator OA can be manually operated by releasing the pipelines of the bottom side oil chamber OAa and the rod side oil chamber OAb of the hydraulic actuator OA to the tank OT. I am doing so.

  With such a configuration, this hydraulic drive unit OU achieves its basic functions well, and even if an abnormal situation occurs, it does not lead to damage of the unit OU, thus ensuring safety and reliability. Accident avoidance is ensured.

  However, in the hydraulic drive unit OU, the slow return valve SR can only be throttled to one kind of flow rate determined by the installed orifice, and as a hydraulic drive unit used for various purposes, its versatility is suitable. It was not enough. Further, when the flow rate is reduced, that is, adjusted, it is necessary to make it easy to use for general users who are not familiar with hydraulic equipment.

Further, as other specific conventional examples of the hydraulic drive unit, there are those described in Patent Document 1 and Patent Document 2, but none of them solves the above problem.
Japanese Patent No. 2824659 (FIG. 1) Japanese Patent Laying-Open No. 2003-172307 (FIG. 1)

  The present invention is intended to improve the above-mentioned problems, and provides a slow return valve that improves the versatility of the hydraulic drive unit and is easy to use for general users, and a hydraulic drive unit including the slow return valve. The purpose is to do.

  The slow return valve of the present invention is a slow return valve that is used in a hydraulic drive unit that independently provides a driven force by a hydraulic pressure to a driven body, and throttles the flow rate of the working fluid that flows out of the hydraulic actuator that generates the drive force. The aperture amount can be selectively set.

  Moreover, the hydraulic drive unit of the present invention is characterized by including a slow return valve having such characteristics.

  According to the slow return valve of the present invention, the throttle amount can be selectively set, so that the versatility of the hydraulic drive unit is enhanced and it is convenient for general users. Moreover, the same effect is demonstrated also as a hydraulic drive unit provided with this slow return valve.

  Embodiments (examples) of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram conceptually showing an example of a hydraulic drive unit provided with a slow return valve of the present invention.

  The hydraulic drive unit 10 is used for, for example, raising and lowering work equipment with respect to the cultivated ground of an agricultural special vehicle, which requires a simple and independent hydraulic drive force, and is also included in the hydraulic drive unit 10. The slow return valve 8 is used in such a hydraulic drive unit 10 to reduce the flow rate of the hydraulic oil flowing out from the hydraulic actuator 2 that generates the driving force.

  The unit 10 includes an electric motor M and a hydraulic pump 1 that pumps hydraulic oil in both forward and reverse directions, and a hydraulic cylinder that is operated by the hydraulic oil and generates a driving force to the driven body W. 2, a tank 3 for storing hydraulic oil in a closed space, an operation check valve 4 for controlling the forward and reverse bidirectional flow of hydraulic oil between the hydraulic pump 1 and the hydraulic cylinder 2, and the hydraulic pump 1 and the tank 3 It is based on the fact that it consists of the switching valve 5 that controls the flow of hydraulic oil in the forward and reverse directions between the above and the slow return valve 8 described above, and that the throttle amount of the slow return valve 8 can be selectively set. Features.

  The basic functions and interrelationships of these hydraulic pump 1, hydraulic cylinder 2, tank 3, operation check valve 4, and switching valve 5 are the hydraulic pump OP, hydraulic actuator OA, and tank constituting the conventional hydraulic drive unit OU. Since it is the same as OT, the operation check valve OC, and the switching valve OI, redundant description is omitted. Reference numeral 2a of the hydraulic cylinder 2 is a bottom side oil chamber, and reference numeral 2b is a rod side oil chamber.

  Here, the relief valves RV1 and RV2 shown in the hydraulic circuit diagram of FIG. 11 are not shown, but these are provided as necessary. In this figure, the operation check valve 4 and the switching valve 5 constituting the hydraulic drive unit 10 are indicated by hydraulic symbols, and the contents will be described in detail with reference to FIG.

  As shown by the same reference numerals in the drawing, the same return valve 8 is used for the hydraulic oil flowing out from the bottom side oil chamber 2a of the hydraulic cylinder 2 in the additional housing 8a that accommodates the entire related parts. A pair of a throttle and a pair of throttle for the hydraulic oil flowing out from the rod-side oil chamber 2b are built in.

  The additional housing 8a has a main valve line 8e penetrating so as to connect a bottom side and rod side line between the hydraulic cylinder 2 and the operation check valve 4, and a branch from the middle of the main valve line 8e. In addition, a pair of additional valve pipes 8h and 8i that are open and connected to the hydraulic cylinder 2 side are provided.

  The main valve line 8e has the same configuration as that of the conventional slow return valve. The orifice 8b restricts the flow rate of the hydraulic oil flowing out from the hydraulic cylinder 2, and the orifice 8b is closed with a predetermined urging force. A spring 8c for energizing the main valve pipe 8e is provided on the hydraulic cylinder 2 side of the main valve pipe line 8e, and a recess 8d for accommodating the spring 8c and the orifice 8b so as not to drop off is provided.

  Orifices 8f and 8g having a predetermined throttle amount are fixed to the openings of the additional valve lines 8h and 8i.

  In addition, a manual valve 8j that opens and closes the branch to the additional valve pipes 8h and 8i independently of the main valve pipe 8e is provided.

  With such a configuration, the slow return valve 8 is configured such that, for the main valve line 8e, when the hydraulic oil flows into the hydraulic cylinder 2, the orifice 8b resists the spring 8c by the pressure of the hydraulic oil. The pipe 8e is opened, and the hydraulic oil flows freely.

  On the other hand, when hydraulic oil flows out from the hydraulic cylinder 2, the orifice 8b covers the main valve pipe line 8e, and only the fixed throttle amount flows out.

  Thus, when only the main valve pipe line 8e is viewed, it functions as a slow return valve with a fixed throttle amount. In this case, conventionally, in order to change the throttle amount, the orifice 8b has to be replaced with another throttle amount.

  However, in this slow return valve 8, if the manual valve 8j is operated to open the additional valve pipe line 8h, the throttle amount of the orifice 8f can be added, and if the additional valve pipe line 8i is opened, the throttle amount of the orifice 8g is increased. If both are opened, the orifice 8f and orifice 8g can be added. As a whole, the orifice 8b alone, orifice 8b + orifice 8f, orifice 8b + orifice 8g, orifice 8b + orifice 8f + orifice 8g. Can be selected and set.

  Therefore, according to the slow return valve 8, the throttle amount can be selectively set, and the throttle return amount required for various applications can be dealt with, thereby improving the versatility of the hydraulic drive unit. In addition, for the general user, it is possible to perform a simple operation of selecting from a predetermined flow rate instead of freely setting the amount of restriction, which improves usability.

  The number of additional valve pipes provided with the predetermined orifice is not limited to the above two as long as it is one or more. Further, the amount of restriction of the orifices is appropriately determined according to the required selected amount of restriction, and the amount of restriction of different orifices may be different or the same.

  In addition, here, the slow return valve 8 having a configuration in which the slow return function is exhibited on each of the bottom side and the rod side of the hydraulic actuator 2 is illustrated, but only one of them functions as necessary. It is also possible to do.

  FIG. 2 is a block diagram conceptually showing another example of a hydraulic drive unit provided with the slow return valve of the present invention. Accordingly, the same parts as those already described are denoted by the same reference numerals and redundant description is omitted. In addition, in the case where there is a separate code for the aggregate of each part, only the code of the aggregate may be shown to avoid complication.

  In the hydraulic drive unit 10 of FIG. 1, the orifices 8f and 8g of the slow return valve 8 are provided in parallel, but in the hydraulic drive unit 10A, the orifices 8m and 8rs of the slow return valve 8A (not shown) The difference is that they are provided in series.

  Specifically, the housing 8k of the slow return valve 8A is provided with a main valve line 8n and one additional valve line 8o branched therefrom.

  The main valve line 8n is different from the main valve line 8e in FIG. 1 in that the orifice 8b, the spring 8c, and the recess 8d are common, but the branch is only one of the additional valve lines 8o. The shape of the manual on-off valve 8p that opens and closes this branch is also different from the shape of the manual on-off valve 8j provided in the main valve line 8e in FIG.

  The manual on-off valve 8p includes a cylindrical portion 8r following the conical portion 8g at the tip thereof. The conical portion 8g opens and closes the additional valve pipe line 8o, and is common to the manual on-off valve 8j of FIG. 1, but the cylindrical part 8r is coupled with an inner peripheral part 8s of the additional valve pipe line 8o described below. The difference is that the orifice is formed.

  The additional valve pipe line 8o is similar to the additional valve pipe lines 8f and 8g in FIG. 1 in that the opening is throttled by an orifice 8m having a predetermined throttle amount, but at the branch portion from the main valve pipe line 8n. The difference is that an inner peripheral portion 8s is provided.

  The inner peripheral portion 8s has an inner diameter that allows the conical portion 8g of the manual opening / closing valve 8p to pass therethrough and forms an orifice having a predetermined throttle amount with respect to the outer diameter of the cylindrical portion 8r.

  In the slow return valve 8A having such a configuration, when the additional valve line 8o is closed by the manual opening / closing valve 8p, the main valve line 8n is the main valve line of the slow return valve 8 of FIG. Functions in the same way as 8e.

  When the manual on-off valve 8p is operated to open, the orifice (labeled 8rs) between the inner peripheral portion 8s of the additional valve pipe line 8o and the cylindrical portion 8r of the on-off valve 8p is activated. 8 m and the orifice 8 rs act in series (this combined orifice is referred to as an orifice 8 mrs). The combined throttle amount in this case can be obtained from knowledge of the hydraulic circuit.

  When the manual opening / closing valve 8p is further opened and the orifice 8rs is not activated, only the orifice 8m is activated.

  Therefore, according to the slow return valve 8A, as a whole, only the orifice 8b, the orifice 8b + orifice 8mrs, and the orifice 8b + orifice 8m can be selected and set from three kinds of restricting amounts, which is the same as the slow return 8 of the first embodiment. The effect of can be demonstrated.

  Note that the number of additional valve pipes provided with the predetermined orifice may be one or more, and is not limited to the one. Further, the amount of restriction of the orifices is appropriately determined according to the required selected amount of restriction, and the amount of restriction of different orifices may be different or the same.

  In addition, here, the slow return valve 8A having a configuration in which the slow return function is exhibited on each of the bottom side and the rod side of the hydraulic actuator 2 is illustrated, but only one of them functions as necessary. This is also possible in the same manner as the slow return valve 8 of the first embodiment.

  FIG. 3A is a configuration diagram conceptually showing another example of a hydraulic drive unit provided with the slow return valve of the present invention, FIG. 3B is a more specific view taken along the line AA in FIG. FIG. 4B is a BB sectional view of (b).

  As shown in FIG. 3, the hydraulic drive unit 10B has an additional housing 8a 'in which the related parts of the slow return valve 8' are incorporated as compared with the hydraulic drive unit 10 of FIG. The valve housing 9 that accommodates 5 is different in that it can be laminated and assembled, which is a characteristic point.

  In addition to this additional housing 8a ', an assembly plate 21 of the hydraulic cylinder 2 is laminated and assembled on the side where the valve housing 9 is not laminated and assembled. That is, the housing 8a ′ is laminated and assembled between the valve housing 9 and the hydraulic cylinder 2 that is a hydraulic actuator.

  By stacking and assembling in this way, the hydraulic pipes provided on both sides are connected in an oil-tight manner without separately connecting hydraulic pipes between the assembled parts. it can.

  The details of the laminated assembly and the internal structure of the housing 8a ′ of the slow return valve 8 ′ will be described in more detail with reference to FIGS. 3B and 3C.

  In the slow return valve 8 ', first, only one of both the bottom side and rod side pipes described in FIG. 1, specifically, in this example, the slow return valve is provided only on the rod side. For this reason, as shown in the drawing, only the main valve line 8e ′ having no orifice is provided on the bottom side below FIGS. 3 (b) and 3 (c).

  On the other hand, on the rod side above FIGS. 3 (b) and 3 (c), a main valve line 8e provided with an orifice 8b and an additional valve line 8i branched from the main valve line 8e and provided with an orifice 8g. Is visible. However, the additional valve line 8h 'provided with another orifice 8f branches from the additional valve line 8i, not from the main valve line 8e.

  One manual valve 8j is provided in the main valve line 8e to open and close the additional valve line 8i, and the other manual valve 8j 'is provided in the additional valve line 8h' and is connected to the additional valve line 8i. Thus, the additional valve pipe line 8h 'is opened and closed.

  Even in such a configuration, the slow return valve 8 'can be selected from three types of throttle amounts, that is, only the orifice 8c, orifice 8c + orifice 8g, orifice 8c + orifice 8g + orifice 8f, by opening and closing the manual valves 8j, 8j'. Although there are few choices, the same effect as the slow return valve 8 can be exhibited.

  Further, in this slow return valve 8 ', the manual valve 8j can be provided at a position overlapping the thickness direction of the additional housing 8a' (left and right direction in FIG. 3B), and the thickness of the additional housing 8a 'is reduced. can do.

  In FIGS. 3B and 3C, the pipe line in the assembly plate 21 of the hydraulic cylinder 2 is 21a, and the pipe line in the valve housing 9 is 9a. Reference numeral 81 denotes a bush in which the recess 8d described with reference to FIG. 1 is formed. Reference numeral 82 denotes a main valve pipe line 8e, an additional valve pipe line 8h ', and an additional valve pipe line 8i on the slow return valve 8' side. , A recess for passing through the conduit 21a (rod side) on the hydraulic cylinder 2 side, reference numeral 83 denotes a main valve conduit 8e 'on the slow return valve 8' side and a conduit 21a (bottom side) on the hydraulic cylinder 2 side. ) Is a recess for distribution.

  The recesses 82 and 83 are filled with O-rings O1 and O2 for securing oil tightness when the additional housing 8a 'of the slow return valve 8' and the assembly plate 21 of the hydraulic cylinder 2 are laminated and assembled. It is rare. The recess 91 of the valve housing 9 and the O-ring O2 have the same function.

  FIG. 4 is a configuration diagram conceptually showing the detailed configuration of the operation check valve in the hydraulic drive unit of FIG. 1.

  In FIG. 4, characteristics of the operation check valve that could not be explained in FIG. 1 will be explained. This characteristic is another characteristic point of the hydraulic drive unit 10 including the slow return valve 8 of the present invention.

  The operated check valve 4 includes a valve accommodating portion 4a, a switching valve 5 accommodated in the central portion of the valve accommodating portion 4a, and a pair of check valves 4b accommodated so as to face each other with the switching valve 5 interposed therebetween. And the switching valve 5 shown in FIG. 1 is housed and integrated.

  In this example, the valve accommodating portion 4a includes a cylindrical accommodating cylinder 4aa and an accommodating cylinder lid 4ab that closes both end openings in an oil-tight manner.

  In order to make the explanation easy to understand, the valve accommodating portion 4a is shown as a cylindrical separate independent part. However, in an actual hydraulic drive unit, the structure body is a part of the structure of the entire unit. It is incorporated therein and includes an internal housing space for the valve housing portion 4a. When the operation check valve 4 is used as a single unit, it is desirable to use such a valve accommodating portion 4a.

  The switching valve 5 and the pair of check valves 4b are oil-tightly housed in the internal housing space of the housing cylinder 4aa of the valve housing portion 4a.

  The switching valve 5 includes a cylindrical spool cylinder 5a that is accommodated in the center of the internal accommodation space of the accommodation cylinder 4aa without any gap, and a spool 5b that is slidably accommodated in the internal column space of the spool cylinder 5a. .

  The spool cylinder 5a is connected to two pipe lines from the hydraulic pump 1 at its cylinder part, and two openings 5ab for allowing the hydraulic oil to flow between these pipe lines, An opening 5ac that does not interfere with the opening 5ab and that allows the hydraulic oil to flow through the pipe line to the tank 3 is provided at the center of the spool cylinder 5a of both the openings 5ab in the cylinder axis direction. .

  The spool 5b has a shape in which two disks are skewered with a cylindrical body having an outer diameter smaller than the outer diameter of the disk, and the outer diameter of the disk portion 5bb is smaller than the inner circumference of the spool cylinder 5a. The outer diameter is slidable.

  As shown in the figure, when the spool 5b is positioned at the center, the distance between the two disk portions 5bb is between the opening 5ab on the two hydraulic pumps 1 side and the opening 5ac on the tank 3 side. It prevents the flow of hydraulic oil. In addition, when one of the spools 5b slides to the bottom side, for example, only the bottom side of the openings 5ab on the two hydraulic pumps 1 side and the flow of hydraulic oil to the opening 5ac to the tank 3 side are permitted. It has become a thing.

  The outer diameter of the middle shaft portion 5bc sandwiched between the two circular disc portions 5bb of the cylindrical body is larger than the degree of maintaining the structural strength of the entire spool 5b, and operates between its outer periphery and the inner periphery of the spool cylinder 5a. It is thinner than the oil can circulate without resistance.

  The protruding length of the outer shaft portion 5ba extending to the outside of the disc portion 5bb is to fully open the opposing check valve 4b when the spool 5b moves to the maximum, and the outer diameter thereof is checked later. It passes through the valve seat hole 4cb of the valve 4b without hindrance so that the hydraulic oil can be easily circulated with the valve seat hole 4cb.

  The respective parts constituting the spool 5b are fixed to each other, and the whole slides integrally.

  With such a configuration, the spool 5b has the above function of the disk portion 5bb, and when one outer shaft portion 5ba opens the check valve 4b on that side, the check valve 4b on this side, the hydraulic pump 1. The distribution of hydraulic oil between the tanks 3 is permitted.

  The pair of check valves 4b are configured identically to each other, and include a valve seat body 4c, a valve body 4d that slides within the valve seat body 4c, and a spring 4h that normally biases the valve body 4d in the closing direction. And.

  The valve seat body 4c is a cylindrical body that is a valve seat hole 4cb, one of which is a smaller opening, and the rod side oil chamber 2b (opposite side) of the hydraulic cylinder 2 is placed in the cylinder portion near the valve seat hole 4cb side. Then, an opening 4ca is provided that allows the hydraulic oil to flow through the pipe line to the bottom side oil chamber 2a).

  The valve body 4d is a cylindrical body whose front end is closed as a conical valve portion 4e and which is the other opening. The spring 4h is accommodated in the inner cylinder portion 4f. The rear end of the spring 4h and the valve seat The housing cylinder lid 4ab of the valve housing portion 4a regulates the rear end of the body 4c.

  The valve seat hole 4cb of the valve seat body 4c is closed by the valve portion 4e of the valve body 4d biased by the spring 4h.

  An opening 4g is provided behind the end of the valve portion 4e of the valve body 4d to allow the hydraulic oil flowing from the opening 4ca to flow also to the inner cylinder portion 4f.

  The point which this operation check valve 4 exhibits both a check valve function and a switching valve function with such a structure is demonstrated below.

FIG. 4 itself shows a stationary body, that is, a state in which the hydraulic pump 1 is not rotating. In this state, no pressure is applied to the hydraulic oil from the hydraulic pump 1 side, and the hydraulic pump 1 and the operation check are performed. Hydraulic oil contained between the internal oil chambers on both sides of the switching valve 5 built in the valve 4, the switching valve 5
The hydraulic oil contained between the central side internal oil chamber and the tank 3 is stationary.

  The left and right check valves 4b of the operate check valve 4 are closed by the urging force of the spring 4h, and hydraulic oil from either the bottom side oil chamber 2a or the rod side oil chamber 2b of the hydraulic cylinder 2 is closed by the check valve 4b. Thus, the stationary state of the hydraulic cylinder 2 is maintained.

  Here, when the hydraulic pump 1 rotates so as to discharge the hydraulic oil to the bottom side port, this hydraulic pressure opens the bottom side check valve 4b, and the hydraulic oil is supplied to the bottom side oil chamber 2a of the hydraulic cylinder 2. .

  At the same time, the spool 5b of the switching valve 5 is also moved to the right side of the figure by this oil pressure to the rod side, allowing the hydraulic oil to flow between the rod side port of the hydraulic pump 1 and the tank 3, and at the same time the rod side of the spool 5b. The outer shaft portion 5ba opens the rod-side check valve 4b, allows the hydraulic oil to flow from the rod-side oil chamber 2b of the hydraulic cylinder 2, and causes the hydraulic cylinder 2 to generate a driving force in the extending direction.

  At this time, the flow of hydraulic oil between the rod side oil chamber 2b of the hydraulic cylinder 2, the check valve 4b on the rod side, and the tank 3 is permitted. In addition to the hydraulic oil from the rod side oil chamber 2b of the hydraulic cylinder 2, The hydraulic oil from the tank 3 flows into the rod side port of the hydraulic pump 1 to cover the shortage of the hydraulic oil flow rate in the rod side oil chamber 2b with respect to the bottom side oil chamber 2a of the hydraulic cylinder 2.

  On the other hand, when the hydraulic pump 1 rotates so as to discharge hydraulic oil to the rod side port, the reverse operation occurs in the switching valve 4 and the check valve 4b, causing the hydraulic cylinder 2 to generate a driving force in the contraction direction, and the hydraulic cylinder The excess hydraulic oil flow rate in the bottom side oil chamber 2 a relative to the second rod side oil chamber 2 b is returned to the tank 3.

  Thus, the interaction of the central switching valve 5 accommodated in the operation check valve 4 and the pair of check valves 4b opposed so as to sandwich the center switching valve 5 functions as a conventional operation check valve while also serving as a switching valve. Yes.

  In other words, the operation check valve 4 of the present invention is a single unit that absorbs and integrates the conventional switching valve, thereby enabling the operation check valve to be multifunctional, and a space for providing a separate switching valve. Expenses, a pipe connecting the switching valve and the check valve, and the like become unnecessary.

  In addition to the effects of the slow return valve 8, the hydraulic drive unit 10 having such an operation check valve 4 can further reduce the size and cost of the apparatus while maintaining its function as a unit. Can do.

  FIG. 5 is a block diagram conceptually showing another example of a hydraulic drive unit provided with the slow return valve of the present invention.

  The hydraulic drive unit 10C is common to the hydraulic drive unit 10 of FIGS. 1 and 4 in that it includes a slow return valve 8, but the operation check valve 4A does not absorb and integrate the switching valve, and the switching valve 5A. The poppet type switching valve 5A is a characteristic point.

  The operated check valve 4A includes a valve accommodating portion 4a, a pilot portion 45i accommodated in the central portion of the valve accommodating portion 4a, and a pair of check valves 4b accommodated so as to face each other with the pilot portion 45i interposed therebetween. I have.

  In this example, the valve accommodating portion 4a includes a cylindrical accommodating cylinder 4aa and an accommodating cylinder lid 4ab that closes both end openings in an oil-tight manner.

  In order to make the explanation easy to understand, the valve accommodating portion 4a is shown as a cylindrical separate independent part. However, in an actual hydraulic drive unit, the structure body is a part of the structure of the entire unit. It is incorporated therein and includes an internal housing space for the valve housing portion 4a. When the operation check valve 4A is used as a single body, it is desirable to use such a valve accommodating portion 4a.

  The pilot portion 45i and the pair of check valves 4b are oil-tightly accommodated in the internal accommodating space of the accommodating cylinder 4aa of the valve accommodating portion 4a.

  The pilot portion 45i includes a cylindrical spool cylinder 45j that is accommodated in the center of the internal accommodation space of the accommodation cylinder 4aa without a gap, and a pilot spool 45l that is slidably accommodated in the internal column space of the spool cylinder 45j. Yes.

  The spool cylinder 45j is connected to the pipe line to the two ports of the hydraulic pump 1 at the cylinder part, and also to the pipe line to the two openings 5cc of the switching valve 5A. Four openings 45k are provided that allow the hydraulic oil to flow between the hydraulic pump 1 and the switching valve 5A.

  The spool 45l has a structure in which small-diameter pilot protrusions 45lb are provided at both ends of a cylindrical body 45la whose outer diameter is slidable on the inner periphery of the spool cylinder 45j. The spool cylinder 45j is partitioned by a spool 45l, and two oil chambers communicating with the respective openings 45k are formed.

  With such a configuration, when the hydraulic pump 1 rotates while the pilot spool 45l always allows the hydraulic oil to flow between the hydraulic pump 1 and the tank 3, the hydraulic pressure of the oil chamber connected to the discharge side of the pilot spool 45l is increased. Since it becomes higher, it moves to the non-ejection side.

  That is, the pilot part 45i exhibits the function of the pilot line OCb in the hydraulic drive unit of FIG.

  The pair of check valves 4b are configured identically to each other, and include a valve seat body 4c, a valve body 4d that slides within the valve seat body 4c, and a spring 4h that normally biases the valve body 4d in the closing direction. And.

  The valve seat body 4c is a cylindrical body that is a valve seat hole 4cb, one of which is a smaller opening, and the rod side oil chamber 2b (opposite side) of the hydraulic cylinder 2 is placed in the cylinder portion near the valve seat hole 4cb side. Then, an opening 4ca is provided that allows the hydraulic oil to flow through the pipe line to the bottom side oil chamber 2a).

  The valve body 4d is a cylindrical body whose front end is closed as a conical valve portion 4e and which is the other opening. The spring 4h is accommodated in the inner cylinder portion 4f. The rear end of the spring 4h and the valve seat The housing cylinder lid 4ab of the valve housing portion 4a regulates the rear end of the body 4c.

  The valve seat hole 4cb of the valve seat body 4c is closed by the valve portion 4e of the valve body 4d biased by the spring 4h.

  An opening 4g is provided behind the end of the valve portion 4e of the valve body 4d to allow the hydraulic oil flowing from the opening 4ca to flow also to the inner cylinder portion 4f.

  The function and effect of this check valve 4b are the same as the check valve OCa built in the operate check valve OC described in FIG. 11. As a result, the operation check valve 4A as a whole is the operation check valve OC of FIG. Exhibits the same functions and effects.

  The switching valve 5A has the same role as the switching valve OI of FIG. 11, but is characterized in that the valve structure is a poppet type.

  The structure is such that a pair of identical members are opposed to each other and are accommodated in the central portion in the valve accommodating portion 51. The valve seat cylinder 5c, the valve element 5d that slides in the valve seat cylinder 5c, and the valve element, respectively. There is provided a spring 5e for urging 5d toward each other.

  The valve accommodating part 51 is comprised from the accommodating cylinder 51a of a cylindrical body, and the accommodation cylinder cover 51b which closes the both-ends opening oil-tightly, and a pair of valve seat cylinder 5c is oil in the internal accommodation space of this accommodation cylinder 51a. Closely contained.

  In order to make the explanation easier to understand, the valve accommodating portion 51 is shown as a cylindrical separate independent part. However, in an actual hydraulic drive unit, the structure of the structural body is a part of the structural body of the entire unit. It is incorporated therein and includes an internal housing space of the valve housing portion 51 formed therein. When the switching valve 5A is used as a single unit, it is desirable to use such a valve accommodating portion 51.

  The valve seat cylinder 5c is a cylindrical body having a stepped inner periphery, and the outer periphery thereof is fitted in the inner periphery of the housing cylinder 51a without any gaps and in an oil-tight manner. The inner peripheral side includes a small diameter portion 5ca and a large diameter portion 5cb, and the small diameter portion 5ca is connected to the small diameter portion 5ca of the valve seat cylinder 5c facing each other. The peripheral wall of the large diameter portion 5cb closest to the small diameter portion 5ca is provided with an opening 5cc that enables the flow of hydraulic oil to and from the pipe line to the hydraulic pump 1, and the peripheral wall of the small diameter portion 5ca is connected to the tank 3. An opening 5cd is provided that enables the flow of hydraulic oil to and from the pipeline.

  The valve body 5d has a shape in which a stepped protrusion is provided on one of the center sides of the disc, and the outer diameter of the disc portion 5da slides with respect to the inner periphery of the large diameter portion 5cb of the valve seat cylinder 5c. It is possible.

  The stepped protrusion is composed of a state-of-the-art small-diameter portion 5db, followed by a larger-diameter medium-diameter portion 5dc, followed by a valve gradient portion 5dd, and the intermediate-diameter portion 5dc is smaller than the small-diameter portion 5ca of the valve seat cylinder 5c. So that the valve gradient portion 5dd comes into contact with the step edge from the small diameter portion 5ca to the large diameter portion 5cb of the valve seat cylinder 5c to completely prevent the flow of hydraulic oil between the two. This is the reason why it is called a poppet type.

  The disk portion 5da is provided with a through hole 5de that allows the working oil to flow from the stepped protrusion side to the protrusionless side.

  The valve body 5d is incorporated in the valve seat cylinder 5c so that the tip of the small diameter portion 5db contacts the tip of the small diameter portion 5db of the opposing valve body 5d.

  The spring 5 e is inserted between the rear surface of the valve body 5 d and the housing cylinder lid 51 b of the valve housing portion 51.

  The switching valve 5A has a pair of poppet valves (a valve seat cylinder 5c and a valve body 5d) arranged coaxially opposite to each other so that the operation of one poppet valve in the closing direction allows the other poppet valve to operate in the opening direction. The function of the switching valve 5A having such a configuration will be described below.

  FIG. 5 itself shows a stationary body, that is, a state in which the hydraulic pump 1 is not rotating. In this state, no pressure is applied to the hydraulic oil from the hydraulic pump 1 side, and the hydraulic pump 1 and the operation check are performed. The hydraulic oil contained between the internal oil chambers on both sides of the pilot portion 45i of the valve 4A and the hydraulic oil contained between the internal oil chamber of the switching valve 5A and the tank 3 are stationary.

  The left and right check valves 4b of the operating check valve 4A are closed by the biasing force of the spring 4h, and the hydraulic oil from either the bottom side oil chamber 2a or the rod side oil chamber 2b of the hydraulic cylinder 2 is closed by the check valve 4b. Thus, the stationary state of the hydraulic cylinder 2 is maintained.

  Here, when the hydraulic pump 1 rotates so as to discharge hydraulic oil to the bottom side port, the hydraulic pressure opens the bottom side check valve 4b, and the hydraulic oil is supplied to the bottom side oil chamber 2a of the hydraulic cylinder 2, At the same time, the pilot spool 45l of the pilot portion 45i is also moved to the right side of the figure by this oil pressure, to the rod side, and the rod-side outer shaft portion 45lb opens the rod-side check valve 4b. The hydraulic oil flow from 2b is allowed, and a driving force in the extending direction is generated in the hydraulic cylinder 2.

  At the same time, the bottom side valve element 5d of the switching valve 5A moves to the right side in the figure, the rod side, the rod side valve element 5d moves to the rod side, and the oil on the stepped protrusion side of the bottom side valve element 5d. The chamber allows the hydraulic oil to flow with the tank 3 via the opening 5cd of the valve seat cylinder 5c, and the amount of hydraulic oil in the rod side oil chamber 2b relative to the bottom side oil chamber 2a of the hydraulic cylinder 2 is insufficient. Is supplied from the tank 3.

  On the other hand, when the hydraulic pump 1 rotates so as to discharge hydraulic oil to the rod side port, the pair of check valves 4b, the pilot portion 45i, and the switching valve 5A of the operate check valve 4A operate in the reverse manner to the above. Driving force in the contracting direction is generated in the cylinder 2, and excess hydraulic oil at that time is allowed to flow through the tank 3 in the bottom side valve body 5 d and is returned to the tank 3.

  In any of the above driving cases, the closing between the valve body 5d of the switching valve 5A and the valve seat cylinder 5c is configured as a poppet type, and the flow of hydraulic oil can be completely closed, and the spool as shown in FIG. Compared with the switching valve 5 of the type, leakage between the bottom side, the rod side, and the tank can be prevented, and the pump efficiency can be improved.

  Further, the predetermined gap between the outer diameter of the intermediate diameter portion 5dc of the valve body 5d of the switching valve 5A and the small diameter portion 5ca of the valve seat cylinder 5c appropriately limits the amount of hydraulic oil passing between the two. Thus, the oil pressure on the tank 3 side acts on the area of the medium diameter portion 5dc only on the stepped protrusion side, and among the forces acting on both sides of the disc portion 5da of the valve body 5d, it acts on the stepless side relatively. The switching force is increased so that the switching action is exhibited.

    Further, the spring 5e always urges the opposing valve body 5d in the center (opposite) direction, and both the valve bodies 5d have their middle diameter portions 5dc engaged with the small diameter portion 5ca of the valve seat cylinder 5c (not shown). State), a standby state maintaining means for maintaining the standby state in which the switching action can be exhibited.

  Such a standby state maintaining means is not limited to the spring of this example, but is one that generates an elastic biasing force and is resistant to hydraulic oil, such as oil-resistant rubber, oil-resistant elastic synthetic resin, etc. There may be.

  The switching valve 5A described with reference to FIG. 5 exhibits the above functions and effects as components of the hydraulic drive unit 10C, and is used in combination with an operation check valve to control the flow of hydraulic oil in both forward and reverse directions. The above-mentioned functions and effects are exhibited as a switching valve.

  In addition to the effects of the slow return valve 8, the hydraulic drive unit 10C provided with such a switching valve 5A exhibits these functions and effects as a unit.

  FIG. 6 is a block diagram conceptually showing another example of the hydraulic drive unit provided with the slow return valve of the present invention.

  This hydraulic drive unit 10D has a slow return valve 8 and an operation check valve 4A in common with the hydraulic drive unit 10A of FIG. 5, but the switching valve 5C is not a poppet type but a spool type and absorbs a relief valve. It is different in that it is integrated, and it is a feature.

  The switching valve 5C includes a valve accommodating part 51, a cylindrical spool cylinder 5f that is oil-tightly accommodated in the valve accommodating part 51 without any gap, and a spool that is slidably accommodated in an internal column space of the spool cylinder 5f. 5h.

  The accommodating cylinder 51a, the accommodating cylinder lid 51b, the two openings 5fa constituting the spool cylinder 5f, and the opening 5fb to the tank 3 constituting the valve accommodating part 51 are the same as the corresponding parts of the switching valve 5B in FIG. .

  What is different is a spool 5h having a relief valve function. The spool 5h includes two cylindrical plates 5ha, and a spring 5hb sandwiched between the cylindrical plates 5ha to urge the cylindrical plates 5ha away from each other. A stop ring 5hc that defines a range in which the cylindrical plates 5ha are separated from each other, a cylindrical plate 5ha, a spring 5hb, and a through shaft 5hd that penetrates the center of the stop ring 5hc are provided.

  The outer diameter of the cylindrical plate 5ha is slidable to the inner diameter of the spool cylinder 5f, and the inner diameter of the cylindrical plate 5ha is slidable to the outer diameter of the through shaft 5hd. The spring 5hb is externally fitted between the two cylindrical plates 5ha of the through shaft 5hd. The stop ring 5hc is fitted in a groove provided at a predetermined position of the through shaft 5hd, and defines the maximum range in which the cylindrical plate 5ha is urged by the spring 5hb and separated from each other.

  Both ends of the penetrating shaft 5hd abut against the opposing storage cylinder lid 51b.

  The two cylindrical plates 5ha urged by the spring 5hb and separated from each other at the restriction position by the stop ring 5hc are in the same positional relationship as the two disc portions 5bb of the spool 5b of the switching valve 5 in FIG. The switching valve 5C provided with the spool 5h normally exhibits the same function and effect as the switching valve 5 of FIG.

  Among the oil chambers on both sides partitioned by the spool 5h when the hydraulic pump 1 is in operation, the discharge-side oil chamber that circulates with the discharge-side port of the pump 1 but does not circulate with the tank 3 for a certain reason or higher. When this occurs, the cylinder plate 5ha on the discharge side moves against the urging force of the spring 5hb in the direction opposite to the discharge side, and passes through the opening 5fb to the tank 3, so that the high-pressure hydraulic oil is transferred to the tank. Returned to 3.

  Thus, the function of the relief valve RV2 of the hydraulic drive unit OU in FIG. 11 is realized by the spool 5h having this configuration, and the relief valve RV2 is absorbed and integrated with the switching valve. As the hydraulic drive unit 10D, In addition to the effects of the slow return valve 8, the effects of cost reduction, resource saving, and compactness are further exhibited.

  Further, the switching valve 5C exhibits the effects of multi-function, space saving, resource saving, and cost reduction.

  FIG. 7 is a configuration diagram conceptually showing another example of a hydraulic drive unit including the slow return valve of the present invention.

  This hydraulic drive unit 10E is common to the hydraulic drive unit 10D of FIG. 6 in that it has a slow return valve 8, but the relief valve is integrated with the operation check valve instead of the switching valve 5B. The difference is that it is 4D.

  That is, the check valve 4b accommodated in the operation check valve 4D is the same as that shown in FIG. This is the same as the switching valve 5 that is excluded and accommodated in the center of the operation check valve 4 of FIG.

  The switching valve 5B is common to the switching valve 5C of FIG. 6, the valve accommodating part 51 (accommodating cylinder 51a, accommodating cylinder lid 51b) is common, the spool cylinder 5f (opening 5fa, opening 5fb), and the spool 5g (outer shaft part). 5ga, the disk portion 5gb, and the middle shaft portion 5gc) are a spool cylinder 5a (opening 5ab, opening 5ac) and a spool 5b (outer shaft) corresponding to the switching valve 5 housed in the center of the operation check valve 4 in FIG. Part 5ba, disc part 5bb, and middle shaft part 5bc), and the functions and effects are also the same.

  The pilot unit 46 includes a spool cylinder 46a and a spool 46d.

  The overall shape of the spool 46d is the same as that of the pilot portion 45i of FIG. 5, and includes two openings 46b that perform the same function at the same position. The difference is that an opening 46c connected to the pipe line to the tank 3 is provided at the center in the cylinder axis direction of the spool 46d so as not to interfere with the two openings 46b.

  The spool 46d having a relief valve function defines two cylindrical plates 46e, a spring 46f that is sandwiched between the cylindrical plates 46e and biases the cylindrical plates 46e away from each other, and a range in which the cylindrical plates 46e are separated from each other. A stop ring 46g, a cylindrical plate 46e, a spring 46f, and a through shaft 46h that passes through the stop ring 46g.

  The outer diameter of the cylindrical plate 46e is slidable to the inner diameter of the spool cylinder 46a, and the inner diameter of the cylindrical plate 46e is slidable to the outer diameter of the through shaft 46h. The spring 46f is externally fitted between the two cylindrical plates 46e of the through shaft 46h. The stop ring 46g is fitted in a groove provided at a predetermined position of the through shaft 46h, and defines a maximum range in which the cylindrical plate 46e is urged by the spring 46f and separated from each other.

  Both ends of the through-shaft 46h abut against the valve portion 4e of the valve body 4d constituting the opposing check valve 4b, and push the valve body 4d open to allow the hydraulic oil to flow.

  The two cylindrical plates 46e, which are biased by the spring 46f and are separated from each other at the restricting position by the stop ring 46g, are in any position of the pilot movement during the normal operation in which the pilot function is performed. However, the flow of the hydraulic oil between the two openings 46b to the hydraulic pump 1 and the opening 46c to the tank 3 is not permitted, and the hydraulic oil is connected to the hydraulic pump 1 and the switching valve via the opening 46b. 5B flows in a state where it is not mixed on the discharge side and suction side of the hydraulic pump 1, respectively.

  For some reason, when the hydraulic pump 1 is operating and one of the oil chambers on both sides partitioned by the spool 46d, for example, the spool 46d is pilot-moved to the most anti-discharge side by being pushed by the hydraulic oil on the discharge side. When a predetermined high pressure or higher occurs, the discharge side cylindrical plate 46e moves against the urging force of the spring 46f in the anti-discharge side direction and passes through the opening 46c to the tank 3, and the high pressure The hydraulic oil is returned to the tank 3.

  Thus, the function of the relief valve RV1 of the hydraulic drive unit OU of FIG. 11 is also realized by the pilot portion 46 of this configuration, and this relief valve RV1 is absorbed and integrated with the operation check valve 4D, and the hydraulic drive unit 10E. As a result, in addition to the effects of the slow return valve 8, the effects of cost reduction, resource saving, and downsizing can be achieved.

  Further, the operation check valve 4D exhibits the effects of multi-function, space saving, resource saving, and cost reduction.

  In this example, the switching valve 5B can be a poppet switching valve 5A (see FIG. 5) in which a pair of poppet valves are coaxially arranged opposite to each other. Compared with the switching valve 5B, the flow of the hydraulic oil between the valve body and the valve seat can be completely closed, leakage between the bottom side, the rod side, and the tank can be prevented, and the pump efficiency can be improved.

  FIG. 8 is a block diagram conceptually showing another example of a hydraulic drive unit equipped with the slow return valve of the present invention. FIG. 9 is a diagram showing the operation of the emergency manual valve of the composite valve in the hydraulic drive unit of FIG. FIG.

  This hydraulic drive unit 10F is common to the hydraulic drive unit 10 of FIG. 1 in that it has a slow return valve 8. In addition, a composite valve 7 in which a relief valve and an emergency manual valve are integrated is provided. It has different points.

  The composite valve 7 includes an emergency manual valve, a valve accommodating portion 7a that coaxially accommodates a portion that functions as a relief valve, a manual valve portion 7i that mainly shares the function as an emergency manual valve, and this manual valve portion. A relief valve element 7t that slides relative to 7i to open and close the valve, and a spring 7z that urges the relief valve element 7t toward the manual valve portion 7i in the direction of closing the valve.

  Among the above-described components, the manual valve portion 7i, the relief valve body 7t, and the spring 7z are accommodated in the valve accommodating portion 7a so as to be coaxially opposed to each other. The accommodating portions provided in the valve accommodating portion 7a are also provided so as to face each other except for the central portion.

  The single composite valve 7 has such a structure in which a pair of two relief valves RV1 on the rod side and bottom side constituting the hydraulic drive unit OU of FIG. 11 and an emergency manual valve MV are integrated. This is because these functions are realized. More precisely, the emergency manual valve in the composite valve 7 is a pair of pipes provided on the rod side and bottom side pipes as compared with the emergency manual valve MV of the hydraulic drive unit OU in FIG. It has become.

  Therefore, if necessary, it is possible to make a simpler configuration excluding one or both of the relief valve and the emergency manual valve constituting the composite valve 7.

  In this example, the valve accommodating portion 7a is assumed to be entirely cylindrical, and a plurality of stepped holes penetrating from the end surface to the other end surface facing each other are formed in the center facing.

  In order to make the explanation easy to understand, the valve accommodating portion 7a is shown as a cylindrical separate independent part. However, in an actual hydraulic drive unit, the structure body is a part of the structure of the entire unit. Also included are those that are incorporated therein and in which the stepped holes are formed. When the composite valve 7 is used as a single body, it is desirable to use such a valve accommodating portion 7a.

  The stepped hole is formed from the opposed end surface of the valve accommodating portion 7a toward the center of the both end surfaces, and has a maximum diameter opening hole 7b, a subsequent smaller diameter intermediate hole 7c, and the intermediate hole 7c. A slightly larger-diameter concave hole 7d, a passage hole 7e having a smaller diameter than the intermediate hole 7c, a screw hole 7f having a smaller diameter, followed by a spring hole 7g having a smaller diameter and accommodating the spring 7z. The communication hole 7h is located at the center of the both end faces and has the smallest diameter and communicates with the opposing spring hole 7g.

  The valve accommodating portion 7a is further provided with a pair of hydraulic oil passages 73 penetrating from the one side of the cylindrical outer periphery to the other side through the passage hole 7e. These hydraulic oil passages 73 are respectively hydraulic cylinders. 2 is connected to the bottom oil chamber 2a and the bottom side of the operation check valve 4, and the rod side oil chamber 2b of the hydraulic cylinder 2 and the rod side of the operation check valve 4 are connected.

  Further, the valve accommodating portion 7 a is provided with a hydraulic oil passage 74 that guides hydraulic oil to the outside from the communication hole 7 h, and this hydraulic oil passage 74 is connected to the tank 3.

  The manual valve portion 7i is accommodated from the opening hole 7b of the valve accommodating portion 7a to the screw hole 7f, followed by the flange portion 7j having a smaller diameter than the opening hole 7b and a larger diameter than the intermediate hole 7c. An intermediate portion 7k that is slidable in the intermediate hole 7c, a passage portion 7m that is slidable while maintaining oil tightness with respect to the passage hole 7e, and a male screw that is subsequently engaged with the screw hole 7f. It has an external shape composed of the screw portion 7q.

  On the inner side of the manual valve portion 7i, a valve housing hole 7r having a predetermined depth from the end face of the male screw portion 7q, and a hydraulic oil passage hole 7p with a smaller diameter and a bottom are formed following this.

  The intermediate portion 7k of the manual valve portion 7i has a length just corresponding to the intermediate hole 7c and the concave hole 7d of the valve accommodating portion 7a, and the ring groove 7l is placed on the outer periphery of the manual valve portion 7i at an appropriate position corresponding to the concave hole 7d. Is formed, and a stop ring 72 serving as a valve element drop-off preventing means is fitted in the ring groove 7l.

  The stop ring 72 is restricted by the concave hole 7d. Therefore, the manual valve portion 7i can rotate and slide within the valve accommodating portion 7a only within the restricted range.

  On the outer periphery of the passage portion 7m of the manual valve portion 7i, a section in which the manual valve portion 7i rotates and slides within the restriction range while being screw-engaged between the male screw portion 7q and the screw hole 7f in the valve accommodating portion 7a. Thus, a ring oil groove 7n is provided to allow the hydraulic oil to flow through the hydraulic oil passage 73 provided in the valve accommodating portion 7a. The ring oil groove 7n includes an operation of the oil groove 7n and its inner side. A hydraulic oil passage 7o penetrating the oil passage hole 7p is provided.

  A hexagonal hole 7s for manually rotating the manual valve portion 7i is formed on the outer surface of the flange portion 7j of the manual valve portion 7i.

  The relief valve body 7t is slidably accommodated in the valve accommodating hole 7r of the manual valve portion 7i, and the external side thereof is a valve portion 7u for oil-tightly opening and closing the hydraulic oil passage hole 7p, followed by the valve accommodating hole 7r. A shoulder 7v having a smaller diameter and a slide portion 7w that is slidable with respect to the valve accommodating hole 7r, and a spring 7z that urges the valve body 7t in the valve closing direction are provided on the inner side. And a spring hole 7y opened on the opposite side of the valve portion 7u.

  The relief valve body 7t is also formed with an oil passage 7x that allows the working oil to flow between the outer shoulder 7v and the inner spring hole 7y.

  The spring 7z is accommodated across the spring hole 7g of the valve accommodating portion 7a and the spring hole 7y of the relief valve body 7t, one end of which is regulated at the bottom of the spring hole 7g and the other end of the other spring hole 7y. The bottom portion is biased in the valve closing direction of the relief valve body 7t, that is, the valve portion 7u of the relief valve body 7t closes the hydraulic oil passage hole 7p.

  As can be seen from FIG. 8, such a composite valve 7 opens the relief valve element 7t against the urging force of the spring 7z when, for example, a high pressure exceeding a predetermined level occurs in the hydraulic oil passage 73 on the rod side. , Through the ring oil groove 7n, the hydraulic oil passage 7o, the hydraulic oil passage hole 7p, the valve accommodation hole 7r, the oil passage 7x, the spring hole 7y, the valve accommodation hole 7r, the spring hole 7g, the communication hole 7h, and the hydraulic oil passage 74 3, excess hydraulic oil is released.

  The same applies to the bottom side, and this composite valve 7 exhibits the function of a relief valve for each of the rod side and the bottom side.

  On the other hand, referring to FIG. 9, the manual valve portion 7i on the rod side is manually operated and rotated outward from the axial center of the valve accommodating portion 7a as much as possible within the restriction range by the stop ring 72 and the recessed hole 7d. At this time, the hydraulic oil passage hole 7p of the manual valve portion 7i is opened with respect to the relief valve body 7t that does not act on the urging force beyond the free length of the spring 7z. .

  In this state, the rod side hydraulic oil passage 73, ring oil groove 7n, hydraulic oil passage 7o, hydraulic oil passage hole 7p, valve accommodation hole 7r, oil passage 7x, spring hole 7y, valve accommodation hole 7r, spring hole 7g, A passage is formed in the tank 3 through the communication hole 7h and the hydraulic oil passage 74, the hydraulic oil on the rod side of the hydraulic cylinder 2 can be released, and the bottom side can only be sucked. The hydraulic cylinder 2 can be manually moved in the extending direction, and functions as an emergency manual valve.

  When the hydraulic cylinder 2 is moved in the pushing direction, it is necessary to manually operate the bottom-side manual valve portion 7i.

  Further, as described above, the manual valve portion 7i is regulated by the interaction between the stop ring 72 and the recessed hole 7d, and does not fall off from the valve accommodating portion 7a.

  Therefore, it is necessary to consider contamination (intrusion of foreign matter) at the time of reassembly, preventing the omission of the manual valve part, which is a built-in component, preventing omissions from being detected, and eliminating the need for reassembly. Demonstrates the effect of being unnecessary. This means that an emergency manual valve function can be handled by an amateur on site, and foolproofing is achieved.

  In addition, the manual valve portion 7i having such a configuration can be manually returned to the normal closed state even after being opened as an emergency manual valve, and can be used repeatedly.

  Thus, according to this composite valve 7, in the hydraulic drive unit, the emergency manual valve and the relief valve can be integrated to realize space saving, cost reduction, and downsizing. It is also demonstrated in the circuit. In addition to the effect of the slow return valve 8, the hydraulic drive unit 10F provided with this composite valve exhibits the effect of the composite valve as a unit.

  FIG. 10 is a configuration diagram conceptually showing another example of the hydraulic drive unit including the slow return valve of the present invention.

  This hydraulic drive unit 10G shows an example in which the above-mentioned various modified valves included in the hydraulic drive unit of the present invention are combined to the maximum, and basically includes a selective slow return valve 8 (FIG. 1). ), The operation check valve 4F is integrated with the switching valve 5C ′ (FIG. 4), and the switching valve 5C ′ is further integrated with the relief valve (FIG. 7). The composite valve 7 described with reference to FIGS. 8 and 9 is provided between the valve 8 and the operation check valve 4F.

  In the hydraulic drive unit of the present invention, such a combination is also possible. In that case, each of the individual effects is exhibited, and in addition to the effect of the slow return valve 8, a synergistic effect obtained by combining these is provided. Is demonstrated as a unit.

  In the first to ninth embodiments, the selective slow return valve is used as a basis, the absorption integration of the switching valve into the operation check valve, the poppet of the switching valve, the switching valve of the relief valve, and the operation check valve are integrated. Various combinations of the composite valve in which the absorption integration, the relief valve and the emergency manual valve are integrated have been described, but these combinations are not limited to those illustrated here, and other combinations are possible, In that case, the synergistic effect of the combination is exhibited.

  In the fourth to ninth embodiments, the combination with the slow return valve 8 has been described. However, the slow return valve 8 may be the slow return valve 8A in FIG. 2 and the slow return valve 8 ′ in FIG. Yes, in that case, the effect of each combination is demonstrated.

  In addition to the hydraulic cylinders described here, the hydraulic actuators include a hydraulic rotary actuator that outputs hydraulic driving force as torque, although there are few problems in adjusting the amount of hydraulic oil flowing in and out.

  In addition, the slow return valve of the present invention is preferably used in a hydraulic drive unit that is widely used by general users.

  Moreover, the hydraulic drive unit of the present invention is equipped with such a slow return valve, and independently gives a driven force by hydraulic pressure to the driven body, so that it can be used in various industries where versatility and general user convenience are required. Can be used in the field.

The block diagram which shows notionally an example of the hydraulic drive unit provided with the slow return valve of this invention The block diagram which shows notionally other examples of the hydraulic drive unit provided with the slow return valve of this invention (A) is the block diagram which shows notionally other examples of the hydraulic drive unit provided with the slow return valve of this invention, (b) is a more specific AA cross-sectional view of (a), (c) is ( BB sectional view of b) In the hydraulic drive unit of FIG. 1, the block diagram which showed notionally the detailed structure of the operation check valve The block diagram which shows notionally other examples of the hydraulic drive unit provided with the slow return valve of this invention The block diagram which shows notionally other examples of the hydraulic drive unit provided with the slow return valve of this invention The block diagram which shows notionally other examples of the hydraulic drive unit provided with the slow return valve of this invention The block diagram which shows notionally other examples of the hydraulic drive unit provided with the slow return valve of this invention FIG. 8 is a configuration diagram showing a state in which the emergency manual valve of the composite valve is opened in the hydraulic drive unit of FIG. The block diagram which shows notionally other examples of the hydraulic drive unit provided with the slow return valve of this invention Hydraulic circuit diagram showing the basic configuration of the hydraulic drive unit

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydraulic pump 2 Hydraulic actuator 3 Tank 4-4E Operate check valve 4a Valve accommodating part 4b Check valve 5-5B Switching valve 7 Compound valve 7a Valve accommodating part 7i Valve body of emergency manual valve 7t Valve body of relief valve 72 Valve body Drop prevention means 8, 8 ', 8A Slow return valve 8a, 8k Additional housing 8f, 8g, 8m Orifice 8h, 8i, 8o Additional pipe 8j, 8p Manual valve 9 Valve housing 10-10G Hydraulic drive unit

Claims (4)

  A slow return valve that is used in a hydraulic drive unit that independently applies a hydraulic drive force to a driven body, and throttles the flow rate of the working fluid that flows out of the hydraulic actuator that generates the drive force. A slow return valve characterized in that it can be set to.   2. The throttle amount can be selectively set by selectively manually opening and closing one or more additional valve pipes having an orifice having a predetermined throttle amount. Slow return valve.   The slow return valve according to claim 1 or 2, wherein the additional housing incorporating the slow return valve is laminated and assembled to a valve housing incorporating other valves.   A hydraulic drive unit, wherein the additional housing incorporating the slow return valve according to claim 3 is laminated and assembled between the valve housing and the hydraulic actuator.

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