JP2585168Y2 - Portable hydraulic actuator relief valve - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relief valve used for a portable hydraulic actuator.

[0002]

2. Description of the Related Art An electric motor, a hydraulic pump provided in a housing connected to one end of the electric motor and driven to rotate by the electric motor, and a hydraulic pump provided in the housing on a side opposite to the electric motor and having a hydraulic pressure A hydraulic cylinder driven by hydraulic oil pumped from the pump and an on-off valve such as a relief valve for maintaining the hydraulic pressure in the hydraulic circuit below a certain limit and a manual or automatic return valve for releasing the hydraulic pressure are integrally provided. A portable hydraulic actuator of a type in which a predetermined work tool is driven by the hydraulic cylinder is known. Such a portable hydraulic actuator is equipped with a cutting tool, a crimping tool, a compression tool, etc. driven by a hydraulic cylinder, so that a cutting work of a reinforcing bar requiring a relatively large load, a large diameter of a large crimping terminal. Work such as crimping to an electric wire and compression of a connecting tubular joint to a pipe can be performed efficiently.

[0003]

[Problems to be Solved by the Invention] Generally, the opening / closing valve of the above-mentioned portable hydraulic actuator does not require a highly accurate valve function, so that the poppet type, the guide piston type, etc., which are relatively simple in structure and easy to miniaturize. Is used. These on-off valves are fixed or formed at one end of a pressing member having a biasing means such as a spring, a hydraulic oil outlet provided at a central portion of the bottom surface of the valve chamber, a bottomed cylindrical valve chamber, and a spring. And a conical valve closing the hydraulic oil outlet according to the urging force. For example, in the case of a relief valve, the relief pressure at the hydraulic oil outlet reaches a predetermined pressure (relief pressure). Also, when the manual return lever is operated in the case of a manual return valve, the hydraulic oil outlet is opened to release the hydraulic pressure.

A valve for closing the hydraulic oil outlet is normally fitted slidably in the axial direction into a bottomed cylindrical valve chamber, so that the radial movement of the valve chamber is suppressed. I have. However, in the portable hydraulic actuator as described above, since the pressure is increased and the size is reduced, the valve chamber is formed with a small diameter,
In particular, the hydraulic oil outlet provided at the center of the bottom of the valve chamber has an extremely small diameter, so it is difficult to perform high-precision machining of the hydraulic oil outlet, and it is inevitable that the center position with the valve chamber varies. . For this reason, when the valve element whose radial movement is suppressed is pressed in the valve closing direction and seats at the hydraulic oil outlet, the valve element does not sit on the entire surface of the hydraulic oil outlet, or the valve element is twisted and smooth. There is a problem that a proper valve operation cannot be obtained.

The present invention has been made in view of the above circumstances, and has as its object to reliably close the valve even when the center position between the valve chamber and the hydraulic oil outlet varies as described above. It is an object of the present invention to provide an on-off valve of a portable hydraulic actuator which can perform a smooth valve operation.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object,
The main point of the present invention is to provide a bottomed cylindrical valve chamber.
And a hydraulic oil outlet provided at the center of the bottom of the valve chamber
With a hydraulic oil outlet that can be opened and closed.
A relief valve for a band hydraulic actuator, wherein (a) the hydraulic oil
Has a diameter larger than the outlet and sits at the hydraulic oil outlet
A spherical valve element closed by closing the hydraulic oil outlet;
(b) the spherical valve element within a predetermined range in the radial direction of the valve chamber.
Spherical valve element holding means for movably holding, (c) the valve chamber
Is fitted movably in the axial direction within theIts circumference
The gap between the surface and the inner peripheral wall of the valve chamber is
Hydraulic oil from the hydraulic oil outlet opened by the spherical valve
Large reciprocating motion based on passing through the gap
Set to the size of the springAccording to the bias ofSaidball
A pressing member for pressing the valve-shaped valve element in the closing direction, (d)The sp
A biasing force setting change device for changing the biasing force of the ring
(E) the maximum amount of movement of the pressing member is independent of the urging force.
A maximum movement amount setting change device for setting
Is included.

[0007]

In this way, since the spherical valve element is held so as to be movable in the radial direction of the valve chamber within a predetermined range, the working oil outlet is formed by machining the working oil outlet. Even if the center positions of the valve chamber and the valve chamber are shifted from each other, the spherical valve element is held movably within the predetermined range by the spherical valve element holding means. It can be easily positioned on the heart. Therefore, when the spherical valve element is pressed in the valve closing direction by the pressing member, the center of the spherical valve element is automatically positioned on the axis of the hydraulic oil outlet by seating, and the entire hydraulic oil outlet is entirely The valve is closed and the valve closing operation is surely performed, and the pressing member fitted into the valve chamber does not twist, so that a smooth valve operation can be obtained. At this time, the gap between the outer peripheral surface of the pressing member and the inner peripheral wall of the valve chamber is pressed by hydraulic oil from the hydraulic oil outlet opened by the spherical valve element due to the generation of relief pressure and passing through the gap. While the member is set to the size that can be reciprocated , the urging force of the pressing member and
Energizing force setting that can change the reciprocating amount independently of each other
A change device and a reciprocating movement setting change device are provided.
Therefore, set them to optimal values and press
The member can be preferably reciprocated. Therefore, when the hydraulic pressure is actuated reaches a predetermined relief pressure, since the spherical valve member reciprocates and an open position and a closed position based on the reciprocating motion of the pressing member, the hydraulic fluid outlet when closing Due to the mutual contact of the seating surface, the spherical valve element, and the pressing member, a tapping sound is continuously generated. In addition, reciprocating biasing force
The setting can be changed independently of the travel distance.
To a size that can prevent the spring constant of the spring from lowering.
The biasing force, that is, the relief pressure can be set to the optimum value while limiting
There is also an advantage that. Therefore, it is easily confirmed by the generation of the continuous sound that the relief valve has been operated due to the end of the operation of the hydraulic actuator or the like , and the relief pressure has been reduced.
Suitable reduction of spring constant for setting
Can be controlled.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a view showing the overall configuration of a portable crimping machine 10 to which a relief valve according to an embodiment of the present invention is applied. The crimping machine 10 includes a grip portion 14 provided with a battery storage portion 12 and held by one hand, and a pump driving electric motor 18 which is turned ON only while a switch 16 provided on the grip portion 14 is pressed.
And a housing 22 in which a gear mechanism for transmitting the rotational force of the electric motor 18, a hydraulic pump element, valves and the like are accommodated and an oil tank 20 is mounted, a hydraulic cylinder 24, and a crimping tool 26 are integrally formed. In preparation. The crimping machine 10 is an example of a portable hydraulic actuator.

FIG. 2 is a diagram showing a hydraulic circuit of the crimping machine 10, wherein a dashed line indicates a hydraulic pump element and valves housed in a housing 22. A hydraulic pump 28 operated by the electric motor 18 is connected to the oil tank 20 via a check valve 30 and to a discharge oil passage 34 via a check valve 32. The discharge oil passage 34 is connected to a supply / discharge oil passage 38 via a check valve 36, and is connected to a relief valve 42 via a branch oil passage 40. The oil supply / discharge passage 38 is an oil passage for supplying hydraulic oil to the pressurizing chamber 44 of the hydraulic cylinder 24 and discharging hydraulic oil from the pressurizing chamber 44.
The relief valve 42 opens when the oil pressure in the circuit becomes unnecessarily high, thereby opening the branch oil passage 40 to the discharge oil passage 4.
6 to relieve the hydraulic oil in the discharge oil passage 34 to the oil tank 20 side.

A manually operated return valve 50 is connected to the supply / discharge oil passage 38 via a branch oil passage 48. The return valve 50 connects the branch oil passage 48 to the discharge oil passage 54 in accordance with the pressing operation of the return lever 52, and the working oil is returned to the oil tank 20 through the discharge oil passage 54.

Crimping machine 10 having the above hydraulic circuit
When the switch 16 is depressed and the hydraulic pump 28 is operated by the electric motor 18, the pressurizing chamber 4 via the check valve 32, the discharge oil passage 34, the check valve 36, and the supply / discharge oil passage 38.
4 is supplied with hydraulic oil, and the piston 56 is moved rightward in FIG. 2 against the urging force of the spring 58. For this reason, the male die 62 is moved to the left in FIG. 1 by the piston rod 60 provided on the opposite side of the pressurizing chamber 44 of the piston 56, and the crimp terminal (see FIG. (Not shown) is performed. After the caulking is completed, the operating oil is returned to the oil tank 20 by pressing the return lever 52, and the male die 62 is returned to the original position by the urging force of the spring 58. In the hydraulic actuator 10 of the present embodiment, the return lever 52 is provided above the switch 16 as shown in FIG.
The pressing operation of the switch 16 and the return lever 52 can be performed continuously with one hand, and the operability is improved.

The structure of the relief valve 42 will be described below. The internal structure of the housing 22 and the cylinder 24 and the hydraulic pump 28 housed in the housing 22
The structures of the valves and the valves are substantially the same as those described in detail in Japanese Utility Model Laid-Open No. 4-89617, Japanese Utility Model Laid-Open No. 5-2808, and the like, and a description thereof will be omitted.

The relief valve 42 has a sectional structure as shown in FIG. That is, a large-diameter portion 68 having a substantially cylindrical bottomed valve chamber 66 and a small-diameter cylindrical portion 72 formed continuously with the large-diameter portion 68 and having a hydraulic oil introduction passage 70.
A valve body 74 having a substantially cylindrical shape, a hydraulic oil outlet 76 opened at the center of the bottom surface of the valve chamber 66 and communicating with the hydraulic oil introduction passage 70, and a hydraulic oil outlet 76 larger than the hydraulic oil outlet 76. A spherical valve 78 having a diameter and closing it, a substantially cylindrical holding member 80 fitted into the valve chamber 66, and a pressing portion 82 inserted through the holding member 80 were provided at the tip. A pressing member 84 and a rod 8 screwed to the open end side of the valve body 74 and provided at the other end of the pressing member 84.
A set screw 88 into which 6 is inserted from one end;
A set screw 90 screwed into a screw hole at the other end of the set screw 88 to limit the axial movement of the pressing member 84 based on the contact with the rod 86; Are urged by a spring 92 supported by a set screw 88 in a direction to press the spherical valve element 78. In this embodiment, the holding member 80 is used as the spherical valve element holding means, the spring 92 is used as the biasing means, and the set screw 88 is used.
Is set to the biasing force setting change means, and the set screw 90 is set
These correspond to fixed change means, respectively.

A cylindrical stepped hole 94 having a bottom and a shape corresponding to the valve body is provided on the surface of the housing 22 on the oil tank 20 side, and the valve body 74 is formed on the outer periphery of the small diameter portion 72. The branch oil passage 40 and the hydraulic oil introduction passage 70 are communicated with each other by being screwed into the stepped hole 94 by a male screw.
The portion of the relief valve 42 protruding outside the housing 22 is contained in a rubber bag 96 in the oil tank 20 and is immersed in the hydraulic oil 98, and is provided at the protruding portion of the valve body 74. The discharge oil passage 46 is connected to the oil tank 20.
It is communicated within. The rubber bag 96 is attached so that the space between the rubber bag 96 and the housing 22 is oil-tight by a seal structure (not shown). A copper washer 100 for making the small-diameter portion 72 oil-tight is provided at the step portion of the stepped hole 94, and the hexagon nuts 102 and 104 prevent the set screw 88 and the set screw 90 from loosening. It is provided for.

FIGS. 4A and 4B are views showing the holding member 80. FIG. 4B is a plan view, and FIG. 4A is a sectional view taken along line aa in FIG. The holding member 80 has an insertion opening 106 through which the pressing portion 82 is inserted at the center, a cross groove 108 formed on one end surface which is in contact with the bottom surface of the valve chamber 66, and two hydraulic oil flow passages on the side surface. The groove 110 is formed at a position facing the axis center.

The holding member 80 has the pressing portion 82 inserted therethrough and holds the spherical valve element 78 so as to be freely movable within a predetermined range in the radial direction of the valve chamber 66 and freely in the axial direction. The inside diameter of the insertion port 106 is larger than the diameter of the spherical valve 78, and the width of the cross groove 108 is smaller than the diameter of the spherical valve 78. The length of the holding member 80 in the axial direction is such that the spherical valve element 78 is
4, when the valve is closed by pressing the gap between the holding member 80 and the large-diameter portion 112 of the pressing member 84.
13 are sized. This is because, when the opening end of the hydraulic oil outlet 76 is set on the basis of the abutment of the spherical valve element 78 when the valve is closed, the position of the large-diameter portion 112 at the time of valve closing is smaller than the initial position. It moves to the outlet 76 side, that is, the upper side in FIG.
This is to prevent the spherical valve element 78 from being depressed due to the contact with the valve element 12.

The operation of the relief valve 42 configured as described above will be described below. In the state shown in FIG.
4, that is, the oil pressure in the branch oil passage 40 is sufficiently low, and the spherical valve element 78 is pressed by the pressing member 84 urged by the spring 92 to be seated at the valve closing position, that is, the opening of the hydraulic oil outlet 76. ing. When the oil pressure in the discharge oil passage 34 becomes equal to or higher than a pressure (relief pressure) set in advance by the hydraulic oil outlet 76, the spring 92, or the like, the spherical valve 78 is moved in the valve opening direction, ie, in FIG. Is moved downward. When hydraulic oil flows into the valve chamber 66 due to the movement of the spherical valve 78, the pressing member 8 passes through the cross groove 108 and the hydraulic oil flow groove 110 formed in the holding member 80.
Hydraulic oil is returned from the discharge oil passage 46 provided in the valve chamber 66 into the rubber bag 96 via a gap between the outer peripheral surface of the large diameter portion 112 and the inner peripheral wall of the valve chamber 66.

When the spherical valve 78 is moved in the valve opening direction, the large diameter portion 112 of the pressing member 84 in addition to the spherical valve 78 is also a pressure receiving surface that receives the hydraulic pressure from the hydraulic oil outlet 76. Therefore, the pressing member 84 is moved against the spring 92 in FIG.
Is increased immediately after the valve is opened, but when the pressure in the discharge oil passage 34 becomes smaller than a predetermined value after a lapse of a predetermined time, the spherical valve 78 is seated at the hydraulic oil outlet 76. The valve is closed. That is, the pressure in the discharge oil passage 34 is P, the relief pressure is P _r , the pressure receiving area when the valve is closed (the cross-sectional area of the hydraulic oil outlet 76) is S ₁ , and the pressure receiving area when the valve is open (the large diameter portion 112 is larger). the cross-sectional area) S _2, if the urging force of the spring 92 and f, P ≧ P relationship P · S ₁ ≧ f when it is _r is satisfied opened, after opening the P · S ₂ The valve closes when <f. From this, the pressure P at the time of closing the valve is P = _Pr
A value represented by S ₁ / S ₂ . In the present embodiment, since S ₁ <S ₂ , the pressure P at the time of closing the valve is reduced by multiplying the relief pressure _Pr by S ₁ / S ₂ . The speed at which the pressure P decreases is determined by the gap between the outer peripheral surface of the large-diameter portion 112 and the inner peripheral wall of the valve chamber 66.
The time from when the valve opens to when the valve closes is determined by the gap. This gap is sized so that the spherical valve 78 can be reciprocated, that is, the valve is repeatedly opened and closed, and the hydraulic pump 28 is continuously operated even after the relief valve 42 is operated. In this case, as shown in FIG. 5A, the hydraulic pressure of the discharge oil passage 34 rises and falls at a constant cycle.

Here, as described above, the relief valve 42 has the spherical valve element 78 having the diameter of the insertion port 106 of the holding member 80.
And the width of the cross groove 108 is smaller than the diameter of the spherical valve 78, so that the spherical valve 78 is free in the radial direction within a range allowed by the inner diameter of the insertion port 106. Can be moved to Therefore, in the valve body 74 in which the small-diameter hydraulic oil outlet 76 is provided on the bottom surface of the valve chamber 66 as in the present embodiment, the hydraulic oil outlet 76 is accurately formed at the center of the bottom surface due to the difficulty of drilling. Not valve room 6
6, when the spherical valve element 78 is pressed in the valve closing direction by the pressing member 84, the spherical valve element 78 fits into the hydraulic oil outlet 76 and the center of the spherical valve element 78 is moved. It is automatically located on the axis of the hydraulic oil outlet 76, and the entire surface of the hydraulic oil outlet 76 is securely closed.
There is no twisting of the pressing member 84, and a smooth valve operation can be obtained.

On the other hand, in a conventional relief valve 114 as shown in FIG. 6, a conical valve element 118 formed at one end of a pressing member 116 is used.
The large-diameter portion 120 of the oil outlet 122
, So as to form a small gap with the valve chamber 66 in the same manner as the gap between the outer peripheral surface of the large-diameter portion 112 and the inner peripheral wall of the valve chamber 66 so as to be sent to the discharge oil passage 46. Therefore, when the center between the hydraulic oil outlet 76 and the valve chamber 66 is misaligned as described above, only a part of the conical valve element 118 is seated in the opening of the hydraulic oil outlet 76. However, the valve was not completely closed, and a smooth valve operation could not be obtained due to the kinking.

In this embodiment, as described above, the gap between the outer peripheral surface of the large diameter portion 112 and the inner peripheral wall of the valve chamber 66 is
Since the oil pressure of the discharge oil passage 34 is set to increase and decrease at a constant cycle, the spherical valve 7
8 repeats the movement between the valve closing position and the valve opening position. Therefore, a continuous tapping sound (signal sound) is generated based on repeated contact between the spherical valve element 78 and the bottom surface of the valve chamber 66 or the pressing portion 82 and contact between the rod 86 and the set screw 90 when the valve is closed. Occurs
It is possible to easily know that the oil pressure of the discharge oil passage 34 has reached a predetermined value (relief pressure), that is, the end of the pressure bonding operation. If the clearance is too large, the hydraulic oil is discharged very quickly when the valve is opened, and the spherical valve 7
Since the valve 8 returns to the valve closing position, there is almost no change in the hydraulic pressure as shown in FIG. On the other hand, if the gap is too small, the amount of hydraulic oil that leaks from the gap and is sent to the discharge oil passage 46 is small and does not decrease to the oil pressure at which the valve closing operation is performed. The seat is not seated on the bottom surface of the valve 66 and no tapping sound is generated, and the oil pressure after the valve is opened is stabilized at a value lower by the amount of the working oil sent to the discharge oil passage 46 as shown in FIG. Will be. Therefore, in any case, a signal sound notifying the end of the work cannot be obtained.

In this embodiment, the adjustment of the relief pressure is performed by changing the amount of screwing of the set screw 88 to change the urging force of the spring 92.
Since the maximum movement amount of No. 4 is performed by changing the screwing amount of the set screw 90, it can be set individually. On the other hand, for example, the conventional relief valve 114 shown in FIG. 6 can change the relief pressure by adjusting the screwing amount of the set screw 124, but has a means for limiting the moving amount of the pressing member 116. Therefore, if the hydraulic pressure rises and the pressing member 116 is suddenly moved downward in FIG. 6, there is a problem that the change in the spring 92 increases and the spring constant tends to decrease. Further, a relief valve 128 having a set screw 126 as shown in FIG. 7 for preventing the spring constant of the spring 92 from decreasing is also conceivable.
6 contacts the bottom surface 130 of the set screw 126 to prevent a large movement of the spring 92. On the other hand, when the spacing between the pressing member 116 and the bottom surface 130 is to be kept at an appropriate level, the relief pressure is reduced. This made it impossible for the set screw 126 to assume a free position for adjustment, which was not practical. According to the structure of the present embodiment, as described above, the adjustment of the relief pressure and the adjustment of the maximum movement amount can be performed separately from each other.
Optimum adjustment of the relief pressure is possible while preventing the spring constant from decreasing.

In the relief valve 42 of this embodiment, the portion protruding from the housing 22 is made oil-tight by the oil tank 20 (rubber bag 96), and the discharge oil passage 46 is connected to the valve body 74.
Since the valve body 74 and the oil tank 20 are directly connected to each other, the sealing structure when the valve body 74 is screwed into the housing 22 is simplified, and it is necessary to process the discharge oil passage 46 in the housing 22. Is gone.

FIG. 8 shows an internal drain type relief valve 132.
This is an example in which the present invention is applied. This relief valve 132
Is similar in structure and operation to that of the above-described relief valve 42, and description of common parts is omitted. The housing 22 is provided with a discharge oil passage 46, one end of the discharge oil passage 46 is connected to the oil tank 20, and the other end is formed in a large-diameter portion 133 of the stepped hole 94 into which the valve body 134 is screwed. It is open. The large-diameter portion 133 of the stepped hole 94 is slightly larger in diameter than the large-diameter portion 135 of the valve body 134, and the outer peripheral surface of the large-diameter portion 135 of the valve body 134 and the large-diameter portion 133 of the stepped hole 94 are formed. A gap 136 is formed between the inner peripheral wall and the inner peripheral wall. A large number of outlets 138 are provided in the large diameter portion 135 of the valve body 134 by a predetermined number (for example, 2 to 4).
When the hydraulic pressure of the discharge oil passage 34 given from the branch oil passage 40 reaches the relief pressure, the spherical valve 78
When the hydraulic oil outlet 76 is opened by being pressed downward, the hydraulic oil passing through the gap between the outer peripheral surface of the pressing member 84 and the inner peripheral wall of the valve chamber 66 passes through the discharge port 138 and the gap 136. It is guided to the discharge oil passage 46. An O-ring 140 is fitted to make the gap 136 oil-tight, and the valve chamber 66
In order to make the set oil-tight, a cap nut 142 that covers the projecting side of the set screw 90 is used as a nut that prevents the set screw 88 from loosening, and a copper washer 144 is provided between the valve element 134 and the cap nut 142. It is interposed.

FIG. 9 is a view showing a relief valve 146 in which the holding member 80 and the pressing member 84 in the relief valve 42 of FIG. 3 are integrally formed. This relief valve 146
In, the pressing member 148 includes a pressing portion 152 having a holding portion 150 at one end, and a rod 86 provided at the other end of the pressing portion 152. Holder 1
50, as shown in FIG. 10, a cross-shaped groove 154 and a spherical valve element holding portion 156 having a substantially circular cross section provided at the center of the end face.
The diameter of the spherical valve element holding portion 156 is larger than the diameter of the spherical valve element 78, and the width of the cross groove 154 is smaller than the diameter of the spherical valve element 78. Also,
On a side surface of the pressing portion 152, a predetermined number (for example, four) of oil guide paths 158 for guiding hydraulic oil to the other end of the pressing portion 152 are formed. The gap between the outer peripheral surface 160 on the other end side of the pressing portion 152 and the inner peripheral wall of the valve chamber 66 is the same as the gap between the outer peripheral surface of the large-diameter portion 112 of the relief valve 42 and the inner peripheral wall of the valve chamber 66. The spherical valve 78 is sized to reciprocate.

In the above embodiment, the relief valve according to the present invention is applied to the crimping machine 10 having the manual return valve 50 which is opened and closed by the pressing operation of the return lever 52. FIG. 11 shows a hydraulic circuit diagram. A switching valve 204 that is switched according to the supply state of the hydraulic oil from the hydraulic pump 28 is provided, and when the pressing operation of the switch 16 is released, the hydraulic oil in the hydraulic cylinder 24 is operated by the spring 58. The present invention is similarly applied to a relief valve 42 of a hydraulic processing machine configured to be automatically discharged by the above method. The configuration of the switching valve 204 and the overall configuration of the hydraulic actuator using the switching valve 204 are described in detail in Japanese Utility Model Application Laid-Open No. 4-89617 and the like, and will not be described.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be embodied in still another mode.

[0037] For example, although an example in which the present invention is applied to a - relief valve 42,132,14 6 of the crimping machine 10 in the embodiment, the relief valve of the present invention, the cutting machine,
Applied to various portable hydraulic actuators such as rebar bending machines, caulking machines and compression machines, and equipped with a bottomed cylindrical valve chamber and a hydraulic oil outlet provided in the center of the bottom surface. The same applies to other relief valves.

Further, in the above-described embodiment, the on-off valve in which the set screw 88 and the set screw 90 are formed as separate members has been described. For example, the set screw 124 or 126 shown in FIGS. The effect of the present invention can be sufficiently obtained even if is used.

[0039] In addition, the holding member 8 0 you and the holding portion 150
Need not necessarily have the cross grooves 108, 154, etc. , but are formed so as to extend in three directions at equal intervals from the center of the end face of the holding member or one groove provided in one diameter direction. A groove or the like may be provided. The groove provided on the end face of the holding member communicates with a groove extending from the end face to the other end face (a groove provided on the side face in the embodiment) to return the hydraulic oil to the discharge oil path 46 and the like. The shape does not matter in particular, as long as a sufficient oil passage for returning hydraulic oil is formed. Further, the groove extending from the end face to the other end face is not necessarily provided in the outer peripheral portion as in the embodiment, and may be a hole penetrating between both end faces. In the pressing member 148 in which the holding portion 150 and the pressing portion 152 are integrally formed, the groove 158 may be a hole that penetrates from the end face provided with the holding portion 150 in the direction of the outer peripheral surface 160. .

Further, the shape of the portion corresponding to the spherical valve element holding means, the insertion hole 106 necessarily shown in the embodiment, even if it is not circular cross-section as spherical valve member holding part 15 6 may, in a square or the like good. The shape of the spherical valve element holding means is not particularly limited, as long as the spherical valve element 78 can be moved within a predetermined range so that the hydraulic oil outlet 76 and the like can be reliably closed.

The inner peripheral wall of the valve chamber 66 and the pressing member 84
Gap between the outer peripheral surface or outer peripheral surface 160 of the pressing member 148 of the large-diameter portion 112 of the not name those limited to a size as described in Example.

Although not specifically exemplified, the present invention can be variously modified without departing from the gist thereof.

[Brief description of the drawings]

FIG. 1 is a diagram showing the overall configuration of a crimping machine (hydraulic actuator) including a relief valve to which the present invention is applied.

FIG. 2 is a diagram showing a hydraulic circuit of the crimping machine of FIG.

FIG. 3 is a diagram showing a structure of a relief valve in the hydraulic circuit of FIG.

FIG. 4 is a view showing a structure of a holding member of the relief valve of FIG. 3;

FIG. 5 is a diagram illustrating a change in hydraulic pressure of a discharge oil passage when work is performed using the pressure bonding machine in FIG. 1;

FIG. 6 is a view showing a structure of a conventional relief valve.

FIG. 7 is a view showing the structure of another conventional relief valve.

FIG. 8 is a view showing a relief valve according to another embodiment of the present invention.

FIG. 9 is a view showing a relief valve according to still another embodiment of the present invention.

FIG. 10 is a view showing a main part of a pressing member of the relief valve of FIG. 9;

FIG. 11 shows a hydraulic circuit of a hydraulic actuator having a switching valve .
FIG.

[Explanation of symbols]

42: relief valve 66: valve chamber 76: hydraulic oil outlet 78: spherical valve 80: holding member (spherical valve holding means) 84: pressing member 88: set screw ( urging force setting change device) 90: set screw ( Reciprocating movement setting change device) 92: Spring (biasing means)

Claims (1)

(57) [Scope of request for utility model registration] 1. A portable hydraulic actuator having a bottomed cylindrical valve chamber and a hydraulic oil outlet provided at the center of the bottom surface of the valve chamber, wherein the hydraulic oil outlet is opened and closed. A spherical valve having a diameter larger than that of the hydraulic oil outlet, being seated at the hydraulic oil outlet, and closing the hydraulic oil outlet, and the spherical valve being a valve chamber. Spherical valve element holding means movably holding within a predetermined range in the radial direction of, and fitted in the valve chamber so as to be movable in the axial direction,
The clearance between the outer peripheral surface and the inner peripheral wall of the valve chamber is
From the hydraulic oil outlet which is generated and opened by the spherical valve
Hydraulic oil reciprocates based on passing through the gap
Is set to a size that is, a pressing member for pressing the spherical valve element in the closed direction by the biasing force of the spring, forces set with for setting change an urging force of the spring
Constant changing device, and set the reciprocating movement amount of the pressing member independently of the urging force.
A relief valve for a portable hydraulic actuator, comprising: a reciprocating movement amount setting change device for changing .