JPH08150576A - Electric hydraulic tool - Google Patents

Abstract

PURPOSE: To make it easy to use an electric hydraulic tool by way of miniaturizing and lightening it by screwing a front part of a power unit by way of forming a hollow part to open backward on a rear part of a tool body. CONSTITUTION: A pump plunger 2 is arranged on a tool body 1, a hydraulic circuit is internally provided, a hollow part 4 to open backward is formed on a rear part of the tool body 1, and a front part of a power unit 5 to drive the pump plunger 2 is inserted and installed in this hollow part 4. A return valve chamber 41 is doubly used for a discharge oil passage and a return oil passage of working oil by arranging it in the vertical direction in proximity of a cylinder chamber 8, a low pressure regulating valve and a high pressure regulating valve in the vertical direction are arranged left and right symmetrically on both sides of this return valve chamber 41 and the pump plunger 2 and an intake valve 36 in the vertical direction are arranged in the rear of the return valve chamber 41 respectively collectively on an upper surface by way of putting height of their head parts in order.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an electric hydraulic tool used in processing such as joining and cutting of electric wires.

[0002]

2. Description of the Related Art A hydraulic pump, an oil tank and a motor are attached to a tool body, the motor is driven, and the hydraulic pump is operated to pump the working oil of the oil tank to a cylinder at the front end of the tool body to move the piston. As a portable electric hydraulic tool that is driven to perform crimping and cutting of electric wires with a die, for example, a partially cutaway side view of FIG. 7 and FIG.
A hydraulic crimping tool having the shape shown in the plan sectional view of the relevant part is commercially available. As shown in FIG. 7, this hydraulic crimping tool B is
A cylinder 61 and a hydraulic circuit 62 are formed, and an oil tank 65 is attached to the rear part (right part in the drawing) of the tool body 64 in which the pump plunger 63 is arranged, and at the lower part (lower part in the drawing) of the tool body 64. A pump plunger drive unit 66 composed of a cam crank mechanism is connected, and a speed reducer 67 and a motor 68 are attached to the pump plunger drive unit 66 in parallel with the oil tank 65.

In the hydraulic circuit 62, a suction valve 69 with a strainer, an automatic suction valve strainer 70 and a high pressure regulating valve 71 are inserted on the oil tank side of the tool body 64 (FIG. 8), and the cylinder of the tool body 64 is inserted. Discharge valve 7 on the chamber side
2 (Fig. 8) and the automatic suction valve 73 are inserted, and the push pin 7
The return valve 75 provided with 4 and the pump plunger 63 are vertically arranged in the middle part of the tool body 64. Further, a cylinder head 76 is attached to the cylinder outer peripheral portion of the tool body 64, a tool head 77 is further attached, a fixed die 78 is attached to the tool head 77, and a front end of an output piston 79 accommodated in the cylinder 61 is attached. A movable die 80 is attached, a housing 81 is extended to a lower portion of the tool body 64 to form a handle portion 81a, and a rechargeable battery 82 is detachably attached to a lower end portion of the handle portion 81a. There is.

When the start switch 83 is pushed, the motor 68 is operated by the electric power from the battery 82, the pump plunger 63 of the tool body 64 reciprocates, and the working oil in the oil tank 65 is sucked through the suction valve 69, By way of the discharge valve 72, it is sent to the oil passage 85 in the inner pipe 84 with a fast-forward piston fixed to the tool body 64, the output piston 79 is fast-forwarded, and the high-pressure feed is changed according to the set load of the output piston 79. The electric wire and the terminal are crimped by the fixed die 78 and the movable die 80.

After the work is completed, the return switch 86 is pushed to push the push pin 74 to open the return valve 75, return the working oil to the oil tank 65, and the return force of the return spring 87 returns the output piston 79 to the original position. I am trying to restore it. In the inner pipe 84 with a rapid feed piston, 88 is a low pressure regulating valve for switching the output piston working pressure, and 89 is a return valve for returning the working oil in the cylinder chamber.

[0006]

However, in the hydraulic crimping tool B of FIGS. 7 and 8, the tool body 64 is
Since the oil tank 65, the pump plunger drive unit 66, the speed reducer 67, and the motor 68 are independently attached in an externally connected state, the total weight thereof is heavy, and the oil tank 65 is relatively large in the tool. Since the hydraulic pressure bonding tool B is generally heavy and large in size because it is often used in a relatively narrow space because it retains its volume, its operability may be a problem. There was a situation where improvement was requested.

The present invention has been made in consideration of the above situation, and an object thereof is to further reduce the size of such an electric hydraulic tool, improve operability and workability, and make it a portable type. An object is to provide an electric hydraulic tool that can be suitably used.

[0008]

In order to achieve the above object, the present invention has a hydraulic circuit provided with a pump plunger, an intake valve, a discharge valve, a high pressure regulating valve and a return valve, and a cylinder at the front end. A power unit equipped with a reduction gear motor for linearly reciprocally driving the oil tank and the pump plunger by an eccentric shaft mechanism in a tool body having a piston In the hydraulic tool, a cavity opening rearward is formed in a rear portion of the tool body, a front portion of the power unit is screwed, and an oil chamber formed by a gap between the tool body and the power unit is formed in the cavity portion. A return valve chamber is provided between the hydraulic circuit and the oil tank, and also serves as a discharge oil passage and a return oil passage for the hydraulic oil. A valve, the pump plunger, and the high-pressure regulating valve are arranged on the upper surface of the tool body with the head heights substantially aligned, and the discharge valve is interposed between the pump plunger and the return valve chamber, The oil tank is formed in a substantially rectangular shape that is long in the vertical direction, and is an electric hydraulic tool that is peripherally attached to the peripheral surface of the power unit while being in contact with the rear wall surface of the tool body. The tank is the oil tank between a rear wall surface of the tool body in which a circular ridge surrounding the hollow portion is formed and a seal ring in which a circular double ridge that forms an uneven relationship with the ridge is formed. Is an electric hydraulic tool that is attached to the tool body by pressing the seal ring by the power unit.

[0009]

[Function] When the start switch is turned on and the motor is operated,
In the power unit, the rotation of the motor is decelerated by the speed reducer and output, and is converted into a linear reciprocating motion of the pump plunger by the eccentric shaft mechanism formed on the output rotating shaft.
By operating the hydraulic pump of the pump plunger, the hydraulic oil in the oil tank is pumped to the cylinder chamber via the oil chamber in the cavity and the hydraulic circuit consisting of the suction valve of the tool body, the pump plunger, the discharge valve, and the return valve chamber. Then, the piston is driven to move forward, and the high pressure regulating valve holds the piston at a predetermined pressure to perform hydraulic work such as crimping of the electric wire. After the work,
When the return switch is turned on, the return valve opens, the working oil in the cylinder chamber returns to the oil tank via the return valve chamber and the oil chamber in the cavity, and the piston retracts.

By providing a cavity in the rear part of the tool body and inserting the power unit in the front part by screwing, the hydraulic tool has the power unit taken into the inside of the tool body, resulting in a shorter overall length, which is lightweight and compact. Turn into. Also,
By using the gap space formed between the tool body and the power unit as an oil chamber and using the return valve chamber of the hydraulic oil as the discharge oil passage to the cylinder chamber, the oil passage in the hydraulic circuit can be shortened and reduced, and the suction valve, etc. The restrictions on the arrangement of the valve body are reduced, the main valve body is put on the upper part of the tool body, the width of the tool body is shortened, and the like can be thinned, and the tool can be reduced in weight and size.

Further, by mounting the oil tank in abutment with the rear wall surface of the tool body and surroundingly surrounding the power unit provided with the oil feed port, the oil tank is independent from the conventional one. Without being
It is formed in a rectangular shape that is long in the vertical direction according to the shape of the tool body, and the size in the front-rear direction can be shortened without reducing the capacity of the oil tank, the tool can be downsized, and the oil chamber of the above-mentioned cavity can be formed. Together, they can secure a large amount of hydraulic oil.

In order to closely fix the oil tank to the tool body side, a circular thin convex strip is formed on the rear wall surface of the tool body so as to surround the hollow portion, and a double convex strip having an uneven relationship with the convex strip is formed. This can be achieved by sandwiching the opening edge of the oil tank with a seal ring having a strip and tightening the seal ring with the pressing force of the power unit when inserting it into the cavity.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The electric hydraulic tool of the present invention will be described below with reference to the drawings according to the embodiments. 1 is a partially cutaway side view of an electric hydraulic crimping tool according to the present invention, FIG. 2 is an enlarged side cross-sectional view showing a main part of the hydraulic crimping tool of FIG. 1, and FIG. 3 is an oil tank portion of the hydraulic crimping tool of FIG. 2 is an enlarged sectional view taken along line IV-IV in FIG. 2, FIG. 5 is an enlarged sectional view taken along line VV in FIG. 2, and FIG. 6 is a main part of the hydraulic crimping tool shown in FIG. It is a top view.

In the electric hydraulic crimping tool A shown in FIG. 1, a pump plunger 2 is arranged in a tool body 1, a hydraulic circuit 3 is internally provided, and a rear portion (right side portion in the drawing) of the tool body 1 is opened rearward. A hollow portion 4 is formed, and the front portion (left portion in the drawing) of the power unit 5 that drives the pump plunger 2 is inserted into the hollow portion 4 and is attached to the rear wall surface of the tool body 1. A substantially rectangular oil tank 6 is attached to the outer periphery of the power unit 5 so as to surround it.

A front portion of the tool body 1 is formed in a cylinder 7, and an output piston 10 is housed in a cylinder chamber 8 inside thereof in a state of being biased rearward by a return spring 9. A fast-forward piston 12 having an inner pipe portion 12a integrally formed therein is housed in an inner cylinder chamber 11 formed inside, and the base end portion of the inner pipe portion 12a is screwed into the tool body 1 at the bottom portion of the cylinder chamber 8. Fixed by. A cylinder head 13 is screwed onto the outer periphery of the cylinder 7, and the cylinder head 13
The tool head 14 is attached to the tool head 14, and the fixed die 15 is further attached to the tool head 14, so that work such as crimping can be performed with the movable die 16 attached to the tip of the output piston 10.

A housing 17 is provided by covering the tool body 1, the oil tank 6 and the power unit 5, and the housing 17 is extended downward to form a handle portion 17a, and a start switch 18 and a return switch 19 are arranged. ,
Further, a rechargeable battery 20 is detachably attached to the lower portion of the handle portion 17a.

As shown in the enlarged view of FIG. 2, the power unit 5 includes a motor 21, a speed reducer 22 for reducing the rotation of the motor 21, and an output rotary shaft 23 from the speed reducer 22.
And a reduction gear case 24 covering a part of the output rotation shaft 23 and the reduction gear 22, and a pair of bearings 25A, 2 for holding the output rotation shaft 23 on the tool body 1 and the reduction gear case 24.
It consists of 5B. An eccentric shaft portion 23a is formed at the tip of the output rotary shaft 23, and an outer ring 27 is provided on the eccentric shaft portion 23a via a needle shaft 26.
Reference numeral 4 indicates a state in which the output rotary shaft 23 and the speed reducer 22 excluding the eccentric shaft 23a are integrally covered. Also,
A plurality of oil feed ports 28 are provided on the outer circumference of the speed reducer case 24 on the output rotary shaft 23 side, and the oil tank 6 is attached so as to surround the outer circumference of the oil feed port 28 portion.

As shown in FIG. 3, the oil tank 6 is formed in a rectangular shape elongated in the up-down direction by an elastic rubber material so as to have a substantially same area as the rear wall surface of the tool body 1, and front side opening for attachment to the front and rear side surfaces. It has an edge 29A and a rear side opening edge 29B. On the rear wall surface of the tool body 1, a thin circular ridge 30 is formed so as to surround the opening of the bored cavity 4.
The front side opening edge portion 2 of the oil tank 6 is attached to the ridge 30 portion.
9A, and a sealing ring 32 formed by forming a circular double convex strip 31 forming a curved passage in a concave-convex relationship with the convex strip 30 so as to overlap the opening edge 29A. By using the screwing of the power unit 5 into the hollow portion 4 and pressing it by the reduction gear case 24 portion, the front side opening edge portion 29A portion of the oil tank 6 is sealed in a so-called labyrinth type to prevent oil leakage. I am doing it. The rear side opening edge portion 29B of the oil tank 6 has a reduction gear case 2 like a normal sealing.
4 is sealed with an O-ring 33. Therefore, at least the front side opening edge portion 29A does not need to extend outward for sealing by the O-ring like the rear side opening edge portion 29B, and the front-rear dimension of the oil tank 6 is shortened. .

As described above, the oil chamber 34 is formed between the tool body 1 and the power unit 5 in the hollow portion 4 of FIG.
A clearance 35 is provided between the speed reducer case 24 and the speed reducer case 24, and the oil tank 6 communicates with the oil chamber 34 via the oil feed port 28 and the passage 35 around the rotation shaft. There is.

As shown in FIG. 4, the tool body 1 is internally provided with a pump plunger 2 which is urged by a spring to make an external contact with an outer ring 27 which is mounted on the eccentric shaft portion 23a via a needle shaft 26. The pump plunger 2 is mounted on the outer ring 2 in the oil chamber 34.
7, but the urging force is due to the adjustment of the spring force by the adjusting screw of the head.

Further, as shown in FIG. 2, the height of the adjusting screw portion of the head is aligned behind the pump plunger 2 and a suction valve 36 formed of a steel ball and a spring is provided in parallel, and an oil passage 37 is used to
A plunger chamber 39 for accommodating the pump plunger 2 and the oil chamber 34 are made to communicate with each other, and a return valve 40 made of a spring and a steel ball is provided in parallel in front of the pump plunger 2.

As shown in FIG. 5, the return valve 40 has a push pin 40a which pushes up the steel ball of the return valve 40 to the lower side of the tool body 1, and the lower side of the steel ball is placed in the oil chamber 34. Although the oil passage 53 (FIG. 2) communicating with each other is provided,
A return valve chamber 41 for accommodating the return valve 40 is vertically elongated and has its upper end closed, and as shown in FIG.
A discharge valve 42 formed of a horizontal steel ball and a spring is provided so as to intersect with the upper portion, and the plunger chamber 39 is provided via an oil passage 38.
I am able to communicate with. The return valve chamber 41 communicates with the internal cylinder chamber 11 formed inside the output piston 10 through the oil passage 44 of the inner pipe portion 12a of the fast-forward piston 12 at the intermediate portion.

Further, as shown in FIG. 5, the heights of the adjusting screw portions of the head are symmetrically arranged on both sides of the return valve 40, and the low pressure regulating valve 45 and the valve are formed by steel balls and springs in parallel in the vertical direction. A high pressure regulating valve 46 using a spring is provided. The return valve chamber 41 is also connected to the low pressure regulating valve chamber 48 via an oil passage 47 at an intermediate portion,
A high pressure oil passage 49 communicating with the cylinder chamber 8 is connected to the low pressure regulating valve chamber 48. Further, the high pressure regulating valve 46 has an oil passage 43 communicating with the bottom of the cylinder chamber 8 and an oil passage not shown communicating with the oil chamber 34 of the hollow portion 4, so that the cylinder chamber 8, that is, the communicating oil passage 43 has a predetermined pressure. Release when reached.

That is, in the electric hydraulic crimping tool A, as shown in the plan view of FIG. 6, when viewed from above, the discharge valve 42, the return valve 40, the pump plunger 2, and the suction valve 36.
Are arranged in the front-rear direction, and the return valve 40, the low pressure regulating valve 45 and the high pressure regulating valve 46 are arranged in the left-right direction, and the width dimensions of the cylinder 7, the oil tank 6 and the power unit 5 are aligned, By configuring the oil chamber 34 by the hollow portion 4, the width dimension of the intermediate portion of the tool body 1 is shortened.

Although not shown in detail, as shown in FIG. 2, the output piston 1 is provided at the bottom of the cylinder chamber 8 slightly below.
Oil path 52 (Fig. 5) to compensate for the negative pressure associated with the forward movement of zero.
Allows the oil tank 6 to pass through the oil chamber 34 of the hollow portion 4.
A pair of left and right automatic suction valves 50 communicating with the above are provided so that the oil can be replenished in response to the movement of the working oil by the rapid feed of the rapid feed piston 12. In the electric hydraulic crimping tool A, the top of the housing 17 is partially detachable so that the valve operating pressure of the suction valve 36 can be easily adjusted.

The rapid feed piston 12, which is internally provided to the output piston 10, has a return valve 5 formed of a steel ball and a spring for returning pressure oil from the cylinder chamber 8 to the internal cylinder chamber 11, as will be described later.
One. Further, the tip of the output piston 10 is formed to have a small diameter to have a ball knock type structure using a steel ball and a spring so that the movable die 16 can be attached and detached with one touch.

In the electric hydraulic crimping tool A constructed as described above, by pushing the start switch 18 with a finger, the motor 21 is operated and the output rotary shaft 23 from the speed reducer 22 is rotated to cause eccentricity. The pump plunger 2 in contact with the shaft portion 23a reciprocates up and down. Along with this, the hydraulic oil in the oil tank 6 is sucked from the oil supply port 28 via the passage 35 around the output rotary shaft 23, the oil chamber 34, and the suction valve 36, and passes through the discharge valve 42 and the return valve chamber 41. Then, it enters the internal cylinder chamber 11 via the oil passage 44 of the inner pipe portion 12a, and the output piston 10 is fast-forwarded against the force of the return spring 9.

When the movable die 16 comes into contact with the fixed die 15 through the object to be pressed and a load is applied to the movable die 16 and the hydraulic pressure in the internal cylinder chamber 11 reaches a predetermined pressure, a low pressure communicating with the return valve chamber 41 is established. The control valve 45 opens, pressure oil is supplied into the cylinder chamber 8 behind the output piston 10 through the high-pressure oil passage 49, and the large diameter portion of the output piston 10 is pushed together with the pressurization in the internal cylinder chamber 11, and the entire output piston 10 is pushed. A high pressure is applied by the pressure applied to the pressure receiving area. When the predetermined pressure is reached, the high pressure regulating valve 46 is operated to release the pressure.

When the crimping work is completed, the start switch 18
By pushing the return switch 19 away from the finger, the push pin 40a is pushed, the return valve 40 is opened, and the working oil in the internal cylinder chamber 11 is returned through the oil passage 44 of the inner pipe portion 12a. 40 returns to the oil tank 6 from the oil passage 53 communicating with 40, and the hydraulic oil in the cylinder chamber 8 also returns to the return valve 5
It returns to the oil tank 6 via 1 and the internal cylinder chamber 11, and the output piston 10 is retracted by the urging force of the return spring 9 to release the object to be crimped and return to the original position.

As described above, this electric hydraulic crimping tool A is used.
Characteristically, the front portion of the power unit 5 that drives the pump plunger 2 by incorporating the cavity 4 in the tool body 1 is incorporated, and the oil due to the gap in the cavity 4 between the tool body 1 and the power unit 5 is incorporated. A chamber 34 is formed, and further, the return valve chamber 41 is vertically arranged close to the cylinder chamber 8 so as to be used both as a discharge oil passage and a return oil passage for the hydraulic oil, and on both sides of the return valve chamber 41. Symmetrically, the low-pressure regulating valve 45 and the high-pressure regulating valve 46 in the vertical direction, and the pump plunger 2 and the suction valve 36 in the vertical direction behind the return valve chamber 41,
The heads are arranged at the same height and are collectively arranged on one side, that is, on the upper surface, and the suction valve 36, the high-pressure control valve 46, and the automatic suction valve 50 are passed through the oil chamber 34 of the hollow portion 4 to form the oil tank 6.
By making it communicate with each other, the length of each oil passage in the hydraulic circuit 3 can be shortened as much as possible. In particular, as shown in FIG. 4, the width of the pump plunger 2 of the tool body 1 and the suction valve 36 portion can be reduced. The dimension d is shortened, the diameter of the lower peripheral surface is reduced, and the wall thickness around the cavity 4 can be reduced, and the electric hydraulic crimping tool A is lightened.

Further, the oil tank 6 is attached to the peripheral surface of the speed reducer case 24 in a state of being in contact with the tool body 1 without occupying an independent space, and the hydraulic pressures such as the high pressure regulating valve 46 are also provided. By making the valve longer in the vertical direction in accordance with the tool body 1 arranged in the vertical direction,
The size of the tool can be reduced without reducing the size of the oil tank by reducing the size in the front-rear direction.

Further, since the heads of the valve bodies and the pump plungers described above are gathered on the upper surface, the top of the housing 17 of the electric hydraulic crimping tool A is partially removable, It is possible to easily adjust the operating pressure of each valve by adjusting the spring force.

[0033]

As is apparent from the above description, the present invention has the following effects. (1) A cavity is formed in the rear part of the tool body so that the front part of the power unit that drives the pump plunger can be incorporated, so the power unit of the tool can be attached directly to the lower part or rear part of the tool body as in the past. Compared with the case, it can be significantly lighter and smaller.

(2) The return valve chamber is also used as the discharge path and the return path of the hydraulic oil, each valve body such as the intake valve is arranged on the upper side of the tool body, and the oil communicating between the cavity and the power unit is connected to the oil tank. Since it can be used for the passage, the oil passage can be shortened, and therefore the width dimension of the tool body can be shortened, the diameter of the peripheral surface portion on the lower side can be reduced and the wall thickness can be reduced, and the tool can be further reduced in weight and size.

(3) Since the oil tank is independently formed and is not attached to the tool body, the oil tank is used in the space around the peripheral surface of the reducer case and is attached to the tool body in a contact state. By matching the size of the tool body to the oil tank, it can be formed in a rectangular shape that is long in the up-down direction but short in the front-rear direction.Also, by matching the oil passages in the cavity, while securing a large volume of hydraulic oil, The tool can be miniaturized.

(4) Further, since the valve bodies such as the suction valve are gathered on the tool upper surface so that they can be adjusted to have the same height, it is easy to adjust the valve working pressure and the like, and the assembling at the time of maintenance is also good.
Furthermore, there are additional effects such as good workability during the production of tools.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view of an electric hydraulic crimping tool according to the present invention.

FIG. 2 is an enlarged side sectional view showing a main part of the electric hydraulic crimping tool of FIG.

FIG. 3 is an enlarged side sectional view showing an oil tank portion of the electric hydraulic crimping tool of FIG. 1.

FIG. 4 is an enlarged sectional view taken along line IV-IV in FIG.

5 is an enlarged cross-sectional view taken along the line VV of FIG.

FIG. 6 is a plan view of a main part of the hydraulic pressure bonding tool of FIG. 1.

FIG. 7 is a partially cutaway side view of a conventional electric hydraulic crimping tool.

8 is a plan sectional view of a main part of the electric hydraulic crimping tool of FIG. 7. FIG.

[Explanation of symbols]

 A Electric Hydraulic Crimping Tool 1 Tool Body 2 Pump Plunger 3 Hydraulic Circuit 4 Cavity 5 Power Unit 6 Oil Tank 7 Cylinder 8 Cylinder Chamber 9 Return Spring 10 Output Piston 11 Internal Cylinder Chamber 12 Rapid Feed Piston 12a Inner Pipe 13 Cylinder Head 14 Tool Head 15 Fixed die 16 Movable die 17 Housing 17a Handle portion 18 Start switch 19 Return switch 20 Rechargeable battery 21 Motor 22 Reducer 23 Output rotary shaft 23a Eccentric shaft portion 24 Reducer case 25A, 25B Bearing 26 Needle shaft 27 Outer ring 28 Send Oil port 29A Front side opening edge portion 29B Rear side opening edge portion 30 Convex strip 31 Double convex strip 32 Seal ring 33 O ring 34 Oil chamber 35 Passage 36 Intake valve 37, 38, 43, 44, 47 Oil passage 3 Plunger chamber 40 return valve 40a pushpin 41 return valve chamber 42 a discharge valve 45 low-pressure regulating valve 46 pressure regulating valve 48 low-pressure regulating valve chamber 49 the high pressure oil passage 50 automatic suction valve 51 return valve 52 and 53 oil passage

Claims (2)

[Claims] 1. A hydraulic circuit comprising a pump plunger, an intake valve, a discharge valve, a high pressure regulating valve, and a return valve is internally provided, and a cylinder is formed at a front end portion to accommodate a piston, and a tool head is provided. An electric hydraulic tool in which an attached oil body and a power unit equipped with a motor with a speed reducer that linearly reciprocally drives the pump plunger by an eccentric shaft mechanism are attached to a mounted tool body. Is formed by screwing the front portion of the power unit, and an oil chamber formed by a gap between the tool body and the power unit in the cavity is interposed between the hydraulic circuit and the oil tank, and the hydraulic oil is discharged. A return valve chamber that serves as both an oil passage and a return oil passage is provided, and the suction valve, the pump plunger, and the high pressure regulating valve are provided in the head together with the return valve chamber. It is arranged on the upper surface of the tool body with substantially the same height, the discharge valve is interposed between the pump plunger and the return valve chamber, and the oil tank is formed in a substantially rectangular shape elongated in the vertical direction. An electric hydraulic tool, which is attached to the peripheral surface of the power unit in a state of being in contact with the rear wall surface of the tool body. 2. The oil tank is formed with a rear wall surface of the tool body in which a circular ridge surrounding the opening of the cavity is formed, and a circular double ridge having an uneven relationship with the ridge. The electric hydraulic tool according to claim 1, wherein an opening edge portion of the oil tank is sandwiched between the oil ring and a seal ring, and the oil unit is attached to the tool body by pressing the seal ring by the power unit.