CN113276072A

CN113276072A - Hydraulic tool

Info

Publication number: CN113276072A
Application number: CN202110546225.7A
Authority: CN
Inventors: 周启; 吴阔
Original assignee: Emerson Professional Tools Shanghai Co Ltd
Current assignee: Emerson Professional Tools Shanghai Co Ltd
Priority date: 2021-05-19
Filing date: 2021-05-19
Publication date: 2021-08-20

Abstract

The invention provides a hydraulic tool comprising a drive arrangement and a hydraulic assembly, the hydraulic assembly comprising: a body extending in a longitudinal direction; a plunger pump including a pump chamber and a plunger reciprocating in the pump chamber; a hydraulic cylinder including a hydraulic chamber and a piston reciprocating in the hydraulic chamber; the pump chamber and the hydraulic chamber are defined in the body, arranged in series in the longitudinal direction and in fluid communication; and a hydraulic fluid storage means for supplying hydraulic fluid to the pump chamber, wherein the drive means is arranged in a direction intersecting the longitudinal direction, the hydraulic fluid storage means is provided on a longitudinal section of the outer surface of the body, and the hydraulic fluid storage means extends in the longitudinal direction to envelope a longitudinal extent of the longitudinal section and in a circumferential direction of the body to envelope at least a part of a circumferential extent of the longitudinal section of 360 degrees, such that the hydraulic fluid storage means defines with the outer surface which it envelopes a volume for containing hydraulic fluid.

Description

Hydraulic tool

Technical Field

The present application relates to a hydraulic tool, and in particular to a hydraulic tool having an L-shaped arrangement.

Background

Hydraulic tools are drive devices commonly used in the industrial field, which can be coupled with various tool heads for performing respective industrial operations, such as crimping, shearing, punching operations, etc. The existing hydraulic tools are usually arranged in a direct connection manner (in-line), that is, the hydraulic oil tank, the driving device, the pump device, the hydraulic cylinder and related components are arranged in sequence along the longitudinal direction, which makes the longitudinal dimension of the hydraulic tool larger, and is further not beneficial to operation in a space with limited dimension. Furthermore, since the hydraulic oil tank is disposed at the rearmost portion of the hydraulic tool, the components of the drive apparatus have to be immersed in the hydraulic oil, thereby shortening the service life of the drive apparatus.

In order to relieve the pressure at the end of the operation or when the hydraulic pressure in the hydraulic cylinder reaches a certain threshold value, a relief valve is usually provided in the hydraulic tool. In prior designs, the pressure relief valve is usually arranged transversely to the longitudinal direction of the hydraulic tool, which again increases the transverse dimension of the hydraulic tool to some extent, which is also undesirable.

In addition, because the cylinder body is easy to wear and tear, the cylinder body where the hydraulic cylinder piston is located needs to be maintained or replaced regularly, however, because the cylinder body of the hydraulic cylinder is relatively heavy, even the cylinder body can be an integrated body of the whole hydraulic tool, the difficulty of maintenance or replacement work is large, and the cost is high.

Hydraulic tools are often provided with a separate working head for connection with and manipulation of the tool head. Conventional heads are made from bar or forged steel material by machining means. The construction of the working head results in the need for extensive machining, which increases costs to some extent.

Accordingly, there is a need for a hydraulic tool that is compact and has a small longitudinal dimension to accommodate operations in space-constrained situations. At the same time, there is a need for a hydraulic tool that is improved in the above-mentioned respects.

It should be noted that this background section is intended to illustrate the technical background of the application and is not intended to limit the scope of the application. It should also be noted that the technical content provided in this section is intended to assist the understanding of the present invention by a person skilled in the art, and does not necessarily constitute prior art.

Disclosure of Invention

This summary is provided to introduce a general summary of the invention, and not a comprehensive disclosure of the full scope of the invention or all of its features.

The object of the present invention is to provide a hydraulic tool which is compact and has a reduced longitudinal dimension.

It is another object of the present invention to provide a hydraulic tool that is easy to install and maintain and that is less costly.

It is a further object of the present invention to provide a hydraulic tool that is easier to manufacture.

According to an aspect of the present invention, there is provided a hydraulic tool including:

a drive device; and

a hydraulic assembly, the hydraulic assembly comprising:

a body extending in a longitudinal direction,

a plunger pump including a pumping chamber and a plunger that reciprocates within the pumping chamber, wherein the plunger is coupled with the drive device;

a hydraulic cylinder including a hydraulic chamber and a piston reciprocating within the hydraulic chamber;

wherein the pump chamber and the hydraulic chamber are defined within the body and arranged in series along the longitudinal direction, the pump chamber being in fluid communication with the hydraulic chamber; and

a hydraulic fluid storage device for supplying hydraulic fluid to the pump chamber,

wherein the drive means is arranged in a direction intersecting the longitudinal direction, and the hydraulic fluid storage means is provided on a longitudinal section of the outer surface of the body, and the hydraulic fluid storage means extends in the longitudinal direction to envelope a longitudinal extent of the longitudinal section and in a circumferential direction of the body to envelope at least a part of a circumferential extent of the longitudinal section of 360 degrees, such that the hydraulic fluid storage means defines with the outer surface it envelopes a volume for containing the hydraulic fluid.

In one aspect, the drive arrangement is arranged in a direction perpendicular to the longitudinal direction such that the drive arrangement forms an "L" shaped arrangement with the hydraulic assembly.

In an aspect, the plunger pump of the hydraulic assembly is provided with a first one-way valve allowing only the hydraulic fluid to flow from the hydraulic fluid storage means into the pumping chamber and a second one-way valve allowing only the hydraulic fluid to flow from the pumping chamber into the hydraulic chamber, an inlet end of the first one-way valve being in fluid communication with the hydraulic fluid storage means, an outlet end of the first one-way valve being in fluid communication with the pumping chamber, an inlet end of the second one-way valve being in fluid communication with the pumping chamber, an outlet end of the second one-way valve being in fluid communication with the hydraulic chamber.

In one aspect, respective reset means are provided in the pump chamber and the hydraulic chamber, respectively, for resetting the plunger and the piston, respectively.

In an aspect, the driving device includes a motor and a motion conversion mechanism, the driving device being coupled with the plunger via the motion conversion mechanism, the motion conversion mechanism converting the rotational motion of the motor into a reciprocating motion in the longitudinal direction.

In an aspect, the motion conversion mechanism is an eccentric cam having a rotational axis perpendicular to the longitudinal direction.

In one aspect, the hydraulic fluid storage means is provided on a longitudinal section of the outer surface of the body corresponding to the pump chamber and is in the form of an annular body which surrounds the longitudinal section in a fluid-tight manner in the circumferential direction.

In an aspect, the hydraulic assembly is provided with a pressure relief valve arranged parallel to the longitudinal direction for flowing the hydraulic fluid from the hydraulic chamber back to the hydraulic fluid reservoir for relieving pressure, an inlet end of the pressure relief valve being in fluid communication with the hydraulic chamber and an outlet end of the pressure relief valve being in fluid communication with the hydraulic fluid reservoir.

In one aspect, the body is formed in "two pieces", i.e. comprising a pump body and a cylinder body connected in a fluid-tight manner at one end of the pump body, wherein the cylinder body and the pump body are made of different materials.

In one aspect, the hydraulic tool further comprises a working head which is coupled with the piston to move under the driving of the piston, and the working head is formed by an Al or Mg material through a casting method.

In one aspect, the working head is provided with a bore into which is inserted a reinforcing bushing made of a material that is more rigid than the material of the working head.

Compared with the prior art that the driving device and the hydraulic assembly are arranged in series and/or the body of the hydraulic assembly and the hydraulic fluid storage device are arranged in series, the hydraulic tool has the advantages that the driving device and the hydraulic assembly are arranged to form an L-shaped arrangement, and the hydraulic fluid storage device is arranged to cover the circumferential range of a longitudinal section of the outer surface of the body of the hydraulic assembly along the circumferential direction, so that the longitudinal size of the hydraulic tool is reduced, the installation and the disassembly of the hydraulic fluid storage device are facilitated, and the maintenance and the replacement are facilitated. Furthermore, in the arrangement proposed by the invention, the hydraulic fluid reservoir is arranged remote from the drive, which advantageously avoids unnecessary wear of the components of the drive, and thus a significant cost saving, compared to the prior art, in which the hydraulic fluid reservoir is arranged at the rear end of the drive and thus the components of the drive are immersed in the hydraulic fluid. At the same time, this arrangement of the hydraulic fluid storage device of the invention makes it possible to make it from a material such as rubber, which further contributes to cost savings.

Furthermore, since the pressure relief valve of the present invention is arranged parallel to the longitudinal direction of the hydraulic assembly, the transverse dimension of the hydraulic tool is reduced. Further, since the pressure relief valve is arranged parallel to the longitudinal direction, the pressure relief valve may be arranged in the body alongside the pump chamber or the plunger, which also allows the longitudinal dimension of the hydraulic tool to be further reduced. Therefore, the overall size of the hydraulic tool is more compact.

Furthermore, since the invention makes it possible to provide a "two-piece" body, i.e. a separate cylinder and pump body, it is possible to manufacture the cylinder and pump body from different materials. This makes it possible to manufacture the cylinder block using only relatively expensive materials, but with high wear resistance, thus avoiding waste of materials and saving costs considerably. At the same time, the cylinder and the pump body are formed in two parts, so that the replacement and maintenance become more convenient.

Finally, because the working head of the present invention can be formed by casting using Al or Mg materials, this avoids the need for extensive machining of conventional hydraulic tool working heads using bar or forged steel, thereby reducing machining time, cost, and weight.

Drawings

The features and advantages of one or more embodiments of the present invention will become more readily apparent from the following detailed description, taken in conjunction with the accompanying drawings. It is to be understood that the drawings are shown by way of illustration only and that embodiments of the invention are not limited to the forms shown in the drawings. For purposes of clarity, the same reference numbers will be used in the drawings to identify the same or similar elements, in which:

FIG. 1 illustrates a cross-sectional view of a hydraulic tool according to the present invention;

FIG. 2 illustrates a partial cross-sectional view of a hydraulic tool according to the present invention;

FIG. 3 illustrates a partially exploded perspective view of the cylinder and pump body of the hydraulic tool according to the present invention;

FIG. 4 illustrates a partial cross-sectional view of the cylinder and pump body of the hydraulic tool according to the present invention;

FIG. 5 shows a perspective view of a working head of a hydraulic tool according to the present invention; and

fig. 6 shows a cross-sectional view of a working head of a hydraulic tool according to the present invention.

Detailed Description

The invention is described in detail below with the aid of exemplary embodiments with reference to the attached drawings. It is to be understood that the following detailed description of the present invention is intended for purposes of illustration only and is not intended to limit the invention, its application, or uses.

The use of directional terms such as "upper", "lower", "front", "rear", "proximal", "distal", "vertical", "horizontal" in the description is intended for clarity of illustration only and is not intended to limit the orientation of the associated components. In actual practice, the positional orientation relationship between the components may vary depending on the particular application.

Fig. 1 shows a cross-sectional view of a hydraulic tool according to an embodiment of the present invention. Fig. 2 shows a partial cross-sectional view of the hydraulic tool of fig. 1. A hydraulic tool is generally indicated by reference numeral 1 and has a drive means 10 for powering the hydraulic tool and a hydraulic assembly 12 coupled to the drive means 10, the drive means 10 and the hydraulic assembly 12 being housed in a hydraulic tool housing.

The hydraulic assembly 12 generally has an axis extending in a longitudinal direction Z, which is shown in the drawings of the present application as being in a horizontal direction. The hydraulic assembly 12 includes a plunger pump 141 and a hydraulic cylinder 142 arranged in series in the longitudinal direction, wherein the plunger pump 141 is coupled to the drive device 10 on a proximal side (to the right as viewed in the drawing) in the longitudinal direction thereof and is coupled to the hydraulic cylinder 142 in fluid communication on a distal side (to the left as viewed in the drawing) in the longitudinal direction thereof. The plunger pump 141 includes a pump body 143 extending in a longitudinal direction, a pump chamber 145 defined in the pump body 143 and extending in the longitudinal direction, and a plunger 147 reciprocable in a fluid-tight manner within the pump chamber 145. The hydraulic cylinder 142 includes a cylinder body 144 extending in the longitudinal direction, a hydraulic chamber 146 defined in the cylinder body 144 extending in the longitudinal direction, and a piston 148 reciprocable in a fluid-tight manner within the hydraulic chamber 146. The pump chamber 145 is in fluid communication with the hydraulic chamber 146, and preferably, the longitudinal axis of the pump chamber 145 is arranged coaxially with the longitudinal axis of the hydraulic chamber 146.

The drive means 10 are generally arranged in a direction intersecting the longitudinal direction Z. Preferably, as shown in fig. 1 and 2, the drive means 10 are arranged generally in a direction perpendicular to the longitudinal direction Z, so that the drive means 10 and the hydraulic assembly 12 form an "L" type arrangement. This intersecting arrangement, and more particularly the "L" shaped arrangement, allows the overall longitudinal dimension of the hydraulic tool to be reduced. The drive device 10 may include a motor (not shown) and a motion conversion mechanism 101, and a speed change device (not shown in detail) such as a planetary gear or the like arranged between the motor and the motion conversion mechanism 101. The motor is preferably powered by a battery. The motor may alternatively be powered by other power sources that are otherwise powered. The motor is arranged such that it can generate a rotational movement about an axis T perpendicular to the longitudinal direction Z. In the drawings of the present application, this axis T is shown as extending in a vertical direction.

The motor inputs its rotational motion to the motion conversion mechanism 101, and the motion conversion mechanism 101 converts the rotational motion into a reciprocating motion in the longitudinal direction Z. The motion conversion mechanism 101 is provided to be coupled with the plunger pump 141, more specifically, the plunger 147. Therefore, via the motion conversion mechanism 101, the rotational motion of the motor about the vertical axis can be converted into the reciprocating motion of the plunger 147 in the longitudinal direction.

Preferably, the motion conversion mechanism 101 is implemented as an eccentric cam device coupled to the motor and mounted with its rotation axis coaxial or parallel to the axis T of the rotary motion of the motor. The eccentric cam device is driven by a motor to perform a periodic rotational movement about a vertical rotational axis and correspondingly converts this rotational movement into a periodic reciprocating movement in the longitudinal direction Z.

As shown in fig. 1 and 2, the hydraulic assembly 12 further includes a hydraulic fluid storage device 16, the hydraulic fluid storage device 16 being used to supply hydraulic fluid to the plunger pump 141, and more specifically to the pumping chamber 145, to be driven by the plunger pump 141 to the hydraulic cylinder 142. More specifically, a proximal section of the pump chamber 145 of the plunger pump 141, which is close to the motion conversion mechanism 101, is adapted to receive the plunger 147 such that the plunger 147 reciprocates therein in a fluid-tight manner under the drive of the motion conversion mechanism 101, while a distal section of the pump chamber 145, which is remote from the motion conversion mechanism 101 and is close to the hydraulic cylinder 142, is adapted to receive and contain hydraulic fluid such that the plunger 147 drives the hydraulic cylinder 142 via the hydraulic fluid.

As shown in detail in fig. 2, the hydraulic fluid reservoir 16 is provided on a longitudinal section of the outer surface of the hydraulic assembly 12, preferably on a longitudinal section of the outer surface of the pump body 143, more preferably on a longitudinal section of the outer surface of the pump body 143 corresponding to the distal section of the pump chamber 145 for containing hydraulic fluid.

As further shown in fig. 2, the hydraulic fluid reservoir 16 is arranged to extend in a longitudinal direction to cover the longitudinal extent of the aforementioned longitudinal section of the outer surface of the pump body 143, and in a circumferential direction of the pump body 143 to cover the entire circumference of the longitudinal section, i.e., a circumferential extent of 360 degrees, such that the hydraulic fluid reservoir 16 defines a volume at the longitudinal section with its covered outer surface for containing hydraulic fluid.

In the drawings of the present application, the hydraulic fluid reservoir 16 is generally an annular body that surrounds a longitudinal section of the outer surface of the pump body 143 in the circumferential direction.

Alternatively, the hydraulic fluid storage device 16 may also extend in the circumferential direction to cover only a part of the circumference of the longitudinal section, rather than the entire circumference, i.e. a circumferential extent of less than 360 degrees.

The hydraulic fluid reservoir 16 is fixed in a fluid-tight manner to the outer surface of the pump body 143 of the hydraulic assembly 12, for example, it may be fixed in a threaded manner, or in a riveted, welded, or glued manner.

Preferably, the hydraulic fluid reservoir 16 is embodied as an oil bladder made of a rubber material.

Alternatively, the hydraulic fluid reservoir 16 may be made of any other material suitable for containing hydraulic fluid and being easily secured to the cylinder.

As shown in fig. 2, the overall profile of the cross-section of the hydraulic fluid reservoir 16 is approximately trapezoidal. Alternatively, the overall profile of the cross-section of the hydraulic fluid reservoir 16 may also be a circular arc or other regular or irregular shape.

Compared with the prior art that the hydraulic fluid storage device is generally arranged in series with the hydraulic cylinder and the plunger pump, the hydraulic fluid storage device is arranged to circumferentially cover the outer surface of the plunger pump and together limit the volume for containing the hydraulic fluid, so that the longitudinal size of the hydraulic tool is further reduced, and the hydraulic fluid storage device is more convenient to mount and dismount, and further convenient to maintain and replace. Furthermore, in the arrangement proposed by the invention, the hydraulic fluid reservoir is arranged at the end of the plunger pump remote from the drive, which advantageously avoids unnecessary wear of the components of the drive, and thus a significant cost saving, compared to the prior art, in which the hydraulic fluid reservoir is arranged at the rear end of the drive and thus the components of the drive are immersed in the hydraulic fluid. Also, since the hydraulic fluid reservoir may be made of a material such as rubber, cost savings are further facilitated.

As shown in detail in fig. 2, the hydraulic assembly 12 further includes a first check valve 331 for allowing the hydraulic fluid contained in the hydraulic fluid storage device 16 to flow into the pump chamber 145 of the plunger pump 141 only in one direction, and a second check valve 332 for allowing the hydraulic fluid in the pump chamber 145 to flow into the hydraulic chamber 146 only in one direction. In the figures of the present application, the first non-return valve 331 is shown arranged in the pump body 143 of the plunger pump 141 and arranged transversely to the longitudinal direction Z. It is contemplated that the first one-way valve 331 may be disposed in other locations or in other orientations. The first check valve 331 has an inlet end in fluid communication with the hydraulic fluid reservoir 16 and an outlet end in fluid communication with the pumping chamber 145, and the outlet end does not interfere with the reciprocating stroke of the plunger 147, that is, hydraulic fluid flowing into the pumping chamber 145 from the outlet end does not enter a proximal section of the pumping chamber 145. The second one-way valve 332 is arranged at a distal section of the pump chamber 145 and is closer to the hydraulic chamber 146 than the first one-way valve 331 in the longitudinal direction Z. The second one-way valve 332 has an inlet end in fluid communication with the pumping chamber 145 and an outlet end in fluid communication with the hydraulic chamber 146, such that the pumping chamber 145 is in fluid communication with the hydraulic chamber 146 via the second one-way valve 332.

A first reset mechanism 31 may be further provided in the pump chamber 145 of the plunger pump 141 for resetting the plunger 147. Preferably, the first return mechanism 31 is a spring return mechanism, and specifically, one end of the spring return mechanism is fixed to or abutted against an end portion of the pump chamber 145, preferably, an end portion on a side close to the motion conversion mechanism 101, and the other end of the spring return mechanism is coupled in a fixed manner with the plunger 147, and is provided such that, when the motion conversion mechanism 101 does not apply or is insufficient in driving force to the plunger pump 141, the force applied to the plunger 147 by the spring return mechanism enables the plunger 147 to be kept in its initial position or retracted position or to be returned to its initial position or retracted position (rightmost position as shown in the figure), and enables one end of the plunger pump 141 to be always kept in abutment with the motion conversion mechanism 101.

Similarly to the first restoring mechanism 31 described above, a second restoring mechanism 32 may also be provided in the hydraulic chamber 146 of the hydraulic cylinder 142 for restoring the piston 148. Preferably, the second return mechanism is a spring return mechanism, in particular, one end of which is fixed or abutted to an end of the hydraulic chamber 146, preferably, an end on a side close to the free end, and the other end of which is fixedly coupled with the piston 148 and is arranged such that when both the plunger pump 141 and the hydraulic cylinder 142 are in an inoperative state, a force exerted by the spring return mechanism on the piston 148 causes the piston 148 to remain in or be able to return to its initial or retracted position (the rightmost position as shown in the drawing).

The hydraulic assembly 12 further comprises a pressure relief valve 34 located between the hydraulic cylinder 142 and the fluid reservoir 16, the pressure relief valve 34 being arranged to open automatically when the instantaneous hydraulic pressure in the hydraulic cylinder 142 reaches a preset threshold value, for example 700bar, to enable hydraulic fluid in the hydraulic cylinder 142 to flow back into the hydraulic fluid reservoir 16 to relieve the pressure. Additionally, the pressure relief valve 34 may be arranged to be opened also manually, for example to trigger pressure relief manually in case of a complete hydraulic tool operation, no power on or no power input. The inlet end of the pressure relief valve 34 is in fluid communication with the hydraulic chamber 146 of the hydraulic cylinder 142 and the outlet end is in fluid communication with the hydraulic fluid reservoir 16.

In an embodiment of the invention, as shown in fig. 2, the relief valve 34 is arranged in the pump body 143 of the plunger pump 141 and is arranged parallel to the longitudinal direction of the hydraulic assembly 12 and thus also parallel to the pumping chamber 145 or the plunger 147, that is to say the relief valve 34 is arranged alongside the pumping chamber 145 or the plunger 147.

The arrangement of the pressure relief valve parallel to the longitudinal direction allows the transverse dimension of the hydraulic tool to be reduced compared to the prior art arrangement transverse to the longitudinal axis of the hydraulic assembly. At the same time, the arrangement of the pressure relief valve in the pump body alongside the pump chamber or plunger also allows the longitudinal dimension of the hydraulic tool to be further reduced. Therefore, the overall size of the hydraulic tool is more compact.

The operation of the hydraulic tool according to the present invention is described below. In the initial state, the plunger 147 of the plunger pump 141 and the piston 148 of the hydraulic cylinder 142 are both in their initial positions (i.e., rightmost ends in the drawing). In operation, under the drive of the motor of the drive device 12, the rotation of the motion conversion mechanism 101 pushes the plunger 147 to move the plunger 147 forward from its initial position to its extended position, and when the plunger 147 returns from its extended position to its initial position or retracted position, the first check valve 331 is opened due to the lower pressure in the pump chamber 145 or by the control system, so that the hydraulic fluid in the hydraulic fluid storage device 16 flows into the pump chamber 145. When the plunger 147 moves forward again from the retracted position to the extended position due to the rotation of the motion conversion mechanism 101, the hydraulic fluid is pushed forward and thus the second check valve 332 is forced to open, so that the hydraulic fluid in the pump chamber 145 flows into the hydraulic chamber 146. When the plunger 147 is returned to the retracted position again by the first return mechanism 31, further fluid flows from the hydraulic fluid reservoir 16 into the pumping chamber 145 as the pressure in the pumping chamber 145 decreases, and the above process is repeated. Repeated reciprocation of the plunger 147 pushes more and more hydraulic fluid from the pump chamber 145 into the hydraulic chamber 146, thereby displacing the piston 148 of the hydraulic cylinder 142 when a certain hydraulic pressure is reached to push the piston 148 in a direction away from the plunger 147, i.e., distally, which piston 148 in turn causes further distal movement of the working head 18 to manipulate the tool head. When the hydraulic tool is finished, the relief valve 34 is manually opened to discharge the fluid in the hydraulic chamber 146 to the hydraulic fluid reservoir 16, and the piston 148 is returned to the initial position by the second return mechanism 32.

As described above, in the embodiment of the present invention, the plunger 147 of the plunger pump 141 is accommodated in the pump body 143 to reciprocate in a fluid-tight manner in the pump body 143, and the piston 148 of the hydraulic cylinder 142 is accommodated in the cylinder body 144 to reciprocate in a fluid-tight manner in the cylinder body 144. As shown in fig. 1, the pump body 143 and the cylinder body 144 together constitute the body of the hydraulic assembly 12, that is, the body of the hydraulic assembly 12 of the hydraulic tool according to the present invention is formed in "two pieces", wherein the cylinder body 144 is at least partially received in the pump body 143 at one end of the pump body 143. Fig. 3 and 4 further illustrate a partially exploded perspective view and a partially sectional view of the pump body 143 and the cylinder body 144 of the hydraulic tool according to the present invention. As shown, the cylinder 144 is at least partially housed within the pump body 143, preferably in a fluid-tight manner within the pump body 143. The cylinder 144 may be mechanically connected, preferably threadedly connected, to the pump body 143. Further, a sealing device, such as an O-ring seal 201, may be provided between the pump body 143 and the cylinder body 144.

Forming the body of the hydraulic assembly in "two pieces" makes it possible to manufacture the pump body of the plunger pump and the cylinder body of the hydraulic cylinder from different materials. For example, it is possible to use a more expensive but more wear-resistant material for the cylinder, and a less wear-resistant but less expensive material for the pump body, and to use only the more expensive material for the more worn part of the hydraulic assembly, without having to use such expensive material for the entire body of the hydraulic assembly, which avoids waste of material and greatly saves costs. Simultaneously, set up the cylinder body alone, also make change and maintenance more convenient.

However, as will be appreciated by those skilled in the art, the body of the hydraulic assembly 12 of the hydraulic tool according to the present invention may also be formed in "one piece", i.e., the pump body 143 is formed integrally with the cylinder body 144.

As shown in fig. 1 and 5, the hydraulic tool according to the present invention may further include a working head 18. One end of the working head 18 is coupled to the end of the hydraulic cylinder 142 opposite the plunger pump 141, more specifically to the free end of the piston 148, and is therefore reciprocated with the reciprocation of the piston 148, and the other end of the working head 18 may be detachably connected with a corresponding tool head (not shown) for performing a desired industrial operation, such as crimping, shearing, punching, etc.

Fig. 5 and 6 show a working head 18 according to the invention in perspective view and in cross section. The work head according to the present invention may be fabricated using Al or Mg materials, and due to the characteristics of the Al or Mg materials, the main body structure of the work head 18 may be formed by a casting method, for example, by die casting, metal mold casting, sand casting, etc., and then holes or other structures may be formed using a small amount of machining as needed. The head according to the invention requires only little machining to form the final structure, which avoids the extensive machining required by conventional hydraulic tool heads using bar or forged steel, thus reducing machining time, and thus cost, and weight.

In order to avoid the problem of insufficient strength due to the low hardness or stiffness of the Al or Mg material, a reinforcing bushing 182, for example a steel bushing, may be provided in the region of the working head 18 that is to be subjected to high stresses or pressures, for example a bore portion 181 for connection with a tool head, for example for insertion of a pin of a tool head, in order to meet the strength requirements.

As mentioned above, the present application discloses some embodiments and mentions some possible alternatives, which are all within the scope of the present application. In addition, certain obvious modifications which would be recognized by those skilled in the art would also fall within the scope of the present application.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the specific embodiments/examples described and illustrated in detail herein, and that various changes may be made to the exemplary embodiments by those skilled in the art without departing from the scope defined by the appended claims.

Reference numerals:

drive device 10

Motion conversion mechanism 101

Hydraulic assembly 12

Plunger pump 141

Hydraulic cylinder 142

Pump body 143

Cylinder 144

Pump chamber 145

Hydraulic chamber 146

Plunger 147

Piston 148

Hydraulic fluid reservoir 16

First return mechanism 31

Second reset mechanism 32

First check valve 331

Second check valve 332

Pressure relief valve 34

O-ring seal 201

Working head 18

Hole part 181

The bushing 182 is reinforced.

Claims

1. A hydraulic tool, comprising:

a drive device; and

a hydraulic assembly, the hydraulic assembly comprising:

a body extending in a longitudinal direction,

wherein the pump chamber and the hydraulic chamber are defined within the body and arranged in series along the longitudinal direction, and the pump chamber is in fluid communication with the hydraulic chamber; and

it is characterized in that the preparation method is characterized in that,

the drive means being arranged in a direction intersecting the longitudinal direction, an

The hydraulic fluid storage device is disposed on a longitudinal section of the exterior surface of the body, and the hydraulic fluid storage device extends in the longitudinal direction to encompass a longitudinal extent of the longitudinal section and extends in the circumferential direction of the body to encompass at least a portion of a circumferential extent of the 360 degrees of the longitudinal section, such that the hydraulic fluid storage device, together with the exterior surface that it encompasses, defines a volume for containing the hydraulic fluid.

2. A hydraulic tool as in claim 1 wherein the drive arrangement is arranged in a direction perpendicular to the longitudinal direction such that the drive arrangement forms an "L" shaped arrangement with the hydraulic assembly.

3. A hydraulic tool as in claim 1 wherein the plunger pump of the hydraulic assembly is provided with a first one-way valve allowing only the hydraulic fluid to flow from the hydraulic fluid storage means into the pumping chamber and a second one-way valve allowing only the hydraulic fluid to flow from the pumping chamber into the hydraulic chamber, an inlet end of the first one-way valve being in fluid communication with the hydraulic fluid storage means, an outlet end of the first one-way valve being in fluid communication with the pumping chamber, an inlet end of the second one-way valve being in fluid communication with the pumping chamber, an outlet end of the second one-way valve being in fluid communication with the hydraulic chamber.

4. A hydraulic tool as in claim 1 wherein the pump chamber and the hydraulic chamber are provided with respective return means for returning the plunger and the piston, respectively.

5. A hydraulic tool as in claim 2 wherein the drive arrangement comprises a motor and a motion conversion mechanism, the drive arrangement being coupled with the plunger via the motion conversion mechanism, the motion conversion mechanism converting the rotational motion of the motor to a reciprocating motion in the longitudinal direction.

6. A hydraulic tool as in claim 5 wherein the motion conversion mechanism is an eccentric cam having an axis of rotation perpendicular to the longitudinal direction.

7. A hydraulic tool as in claim 1 wherein the hydraulic fluid storage means is provided on a longitudinal section of the exterior surface of the body corresponding to the pump chamber and is in the form of an annular body surrounding the longitudinal section in a fluid tight manner in the circumferential direction.

8. A hydraulic tool as in any of claims 1 to 7 wherein the hydraulic assembly is provided with a pressure relief valve arranged parallel to the longitudinal direction for flowing the hydraulic fluid from the hydraulic chamber back to the hydraulic fluid reservoir for relieving pressure, an inlet end of the pressure relief valve being in fluid communication with the hydraulic chamber and an outlet end of the pressure relief valve being in fluid communication with the hydraulic fluid reservoir.

9. A hydraulic tool as in any one of claims 1 to 7 wherein the body is formed in "two pieces" comprising a pump body and a cylinder body connected in a fluid tight manner at one end of the pump body, wherein the cylinder body is made of a different material than the pump body.

10. The hydraulic tool of any one of claims 1 to 7, further comprising a working head coupled with the piston to be moved by the piston, and the working head is formed of an Al or Mg material by a casting method.

11. A hydraulic tool as in claim 10 wherein the working head is provided with a bore into which is inserted a reinforcing bushing made of a material having a greater rigidity than the material of the working head.