Power tool

Abstract

To provide a power tool excellent in operation reliability even if tank capacity is reduced while using an oil tank made of rubber or elastomer.SOLUTION: A power tool 1 includes: a body 2 having an oil tank 7 made of rubber or elastomer, a cylinder 4, a hydraulic pump 8a for feeding hydraulic fluid 9b to the cylinder 4 and an electric motor 8b for driving the hydraulic pump 8a; and a tool head 3 that is operated with hydraulic force of the cylinder 4. The hydraulic pump 8a is provided with a suction section 5 of hydraulic fluid 9b. The oil tank 7 is arranged around a suction port 5a formed in the suction section 5. A protrusion section 11 is formed inside the oil tank 7. The protrusion section 11 of the oil tank 7 is formed at a position approaching the suction port 5a when feeding the hydraulic fluid 9b to the cylinder 4.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hydraulic power tool. [Background technology]

[0002] BACKGROUND ART Hydraulic power tools have been proposed in the past (Patent Document 1: Japanese Patent Application Laid-Open No. 2001-018018, Patent Document 2: Japanese Patent Application Laid-Open No. 2022-181248). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-018018 [Patent Document 2] Japanese Patent Publication No. 2022-181248 Summary of the Invention [Problem to be solved by the invention]

[0004] Rubber or elastomer oil tanks are lightweight and have excellent sealing properties. However, for example, if the hydraulic oil becomes hot due to continuous use or an increase in ambient temperature, or if the hydraulic oil leaks over time and the amount of hydraulic oil in the oil tank decreases, the behavior of the oil tank may change and block the hydraulic oil intake port, resulting in a slowdown in piston movement due to insufficient hydraulic oil intake or a malfunction due to a lack of hydraulic oil intake. Furthermore, while minimizing tank capacity is desirable to reduce the size of power tools, reducing tank capacity increases the risk of the inner wall of the oil tank sticking to the intake port. [Means for solving the problem]

[0005] The present invention has been made in view of the above circumstances, and has an object to provide a power tool that uses an oil tank made of rubber or elastomer and has excellent operational reliability even when the tank capacity is small.

[0006] The present invention solves the above problem by the solution disclosed below in one embodiment.

[0007] The electric tool of the present invention comprises a main body having an oil tank made of rubber or elastomer, a cylinder, a hydraulic pump that delivers hydraulic oil to the cylinder, and an electric motor that drives the hydraulic pump, and a tool head that operates by the hydraulic pressure of the cylinder, wherein the hydraulic pump is provided with an intake section for the hydraulic oil and the oil tank is disposed around the intake port of the intake section, and a convex portion is formed on the inside of the oil tank, and the convex portion is formed in a position that approaches the intake port when the hydraulic oil is delivered to the cylinder.

[0008] With this configuration, even if the oil tank with a reduced tank capacity is placed close to the intake port of the intake part, the convex part comes into contact with the intake port first, ensuring a gap between the intake port and the oil tank and ensuring an oil path to the intake part. This results in a compact power tool with high operational reliability.

[0009] As one example, the width of the convex portion of the oil tank is 0.5 times or less the inner diameter of the suction port. With this configuration, the deformation amount of the oil tank can be secured while securing the oil passage. As one example, the length of the convex portion of the oil tank is at least twice the inner diameter of the suction port. With this configuration, the oil passage can be secured without blocking the suction port even if the deformation amount of the oil tank increases. As one example, the convex portion of the oil tank is formed in a position that is in the same direction as the axis of the cylinder when the oil tank is filled with the hydraulic oil. With this configuration, the convex portion is located at a position where the oil tank first approaches the suction port when hydraulic oil is delivered to the cylinder. Furthermore, since the convex portion can be formed in the mold-release direction, the oil tank can be easily molded using a mold.

[0010] The electric tool of the present invention comprises a main body having an oil tank made of rubber or elastomer, a cylinder, a hydraulic pump that supplies hydraulic oil to the cylinder, and an electric motor that drives the hydraulic pump, and a tool head that operates by the hydraulic pressure of the cylinder, wherein the hydraulic pump is provided with an intake section for the hydraulic oil and the oil tank is arranged around an intake port in the intake section, a step is formed in the intake section, and the intake port is formed across the step.

[0011] With this configuration, even if the oil tank with a reduced tank capacity is placed close to the intake port of the intake part, the oil tank comes into contact with the step first, ensuring a gap between the intake port and the oil tank, thereby ensuring an oil path to the intake part. This results in a compact power tool with high operational reliability.

[0012] As one example, the step is at least one time the wall thickness of the oil tank. With this configuration, even if the deformation of the oil tank increases, the oil passage can be secured without blocking the suction port. As one example, the step is formed so as to circumferentially surround the suction section while intersecting the center line passing through the suction port toward the axis of the cylinder. With this configuration, the step is located at the position that the oil tank first approaches when pumping hydraulic oil into the cylinder. Furthermore, since the step can be formed in the circumferential direction of the hydraulic pump, the step can be easily formed by lathe processing or cutting.

[0013] The electric tool of the present invention comprises a main body having an oil tank made of rubber or elastomer, a cylinder, a hydraulic pump that supplies hydraulic oil to the cylinder, and an electric motor that drives the hydraulic pump, and a tool head that operates by the hydraulic pressure of the cylinder, wherein the hydraulic pump is provided with an intake section for the hydraulic oil and the oil tank is arranged around an intake port in the intake section, and a groove-shaped oil passage is formed in the intake section, and the oil passage is formed to be connected to the intake port.

[0014] With this configuration, even if the oil tank with a reduced tank capacity is placed close to the intake port of the intake part, the groove-shaped oil passage ensures an oil passage to the intake part, resulting in a compact power tool with high operational reliability.

[0015] For example, the oil passage is formed in the same direction as the axis of the cylinder, from the intake port to the rear end of the intake section. With this configuration, the rear end of the intake section is exposed in the depth direction of the oil tank, ensuring an oil passage to the intake section. Furthermore, since a groove-shaped oil passage can be formed in the same direction as the axis of the cylinder, it can be easily formed by cutting work such as milling.

[0016] As an example, the oil passage is formed in the circumferential direction of the hydraulic pump, extending from one of the suction ports to another of the suction ports, at a position offset from the center line passing through the suction port toward the axis of the cylinder. With this configuration, the oil tank is positioned so that it is unlikely to come into contact with the groove-shaped oil passage, and the depth of the groove-shaped oil passage can be ensured, thereby preventing wear of the groove-shaped oil passage. Furthermore, since the groove-shaped oil passage can be formed in the circumferential direction of the hydraulic pump, the groove-shaped oil passage can be easily formed by lathe processing.

[0017] For example, the main body has a handle portion on which a start switch for starting the electric motor is disposed, a battery pack for supplying power to the electric motor, and a mounting portion to which the battery pack is detachably mounted. This configuration makes the power tool highly portable. [Effects of the Invention]

[0018] According to the present invention, it is possible to realize a power tool that uses an oil tank made of rubber or elastomer and has excellent operational reliability even when the tank capacity is small. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic side view showing an example of a power tool according to an embodiment of the present invention. [Figure 2]Fig. 2A is a schematic external view showing an example of an oil tank of the power tool of this embodiment, Fig. 2B is a schematic internal structural view of the oil tank shown in Fig. 2A, and Fig. 2C is a schematic internal structural view showing a main part of a first example of the power tool of this embodiment. [Figure 3] 3A is a schematic internal structural view showing a main part of a second example of the power tool of the present embodiment, FIG. 3B is a schematic longitudinal sectional view of the suction part of the second example, and FIG. 3C is a schematic transverse sectional view of the suction part of the second example. [Figure 4] Fig. 4A is a schematic internal structural view showing the main parts of a third example of the power tool of this embodiment, Fig. 4B is a schematic longitudinal sectional view of the suction part 5 of the third example, and Fig. 4C is a schematic transverse sectional view of the suction part of the third example. [Figure 5] 5A is a schematic internal structural view showing a main part of a fourth example of the power tool of the present embodiment, FIG. 5B is a schematic longitudinal sectional view of the suction part of the fourth example, and FIG. 5C is a schematic transverse sectional view of the suction part of the fourth example. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. This embodiment can be applied to an electric compressor, an electric crimping machine, an electric cutter, and other known hydraulic power tools. In all drawings used to explain the embodiment, components having the same function are designated by the same reference numerals, and repeated description thereof may be omitted.

[0021] FIG. 1 is a schematic diagram showing an example of a power tool 1 according to this embodiment. The power tool 1 includes a main body 2 having a hydraulic pump 8a that supplies hydraulic oil 9b to a cylinder 4, an electric motor 8b that drives the hydraulic pump 8a, and a battery pack 14b that supplies power to the electric motor 8b, and a tool head 3 that is actuated by the hydraulic force of the cylinder 4. This embodiment is a cordless tool that is handheld by a worker on-site. To facilitate the explanation of the positional relationship of each part of the power tool 1, the directions are indicated by X, Y, and Z arrows in the drawing.

[0022] The piston 4a reciprocates along an axis P1. That is, the piston 4a advances in the direction of the Y arrow in the drawing and retreats in the opposite direction to the Y arrow in the drawing. The example in FIG. 1 is a power tool 1 equipped with a tool head 3 for compression. The power tool 1 operates normally in any orientation, regardless of the orientation during work.

[0023] The main body 2 has a cylinder 4, a hydraulic pump 8a disposed at the rear of the cylinder 4, an electric motor 8b with a reducer disposed at the rear of the hydraulic pump 8a, and a control circuit 6 that drives and controls the electric motor 8b. As an example, the hydraulic pump 8a is a swash plate type piston pump having a swash plate cam that is rotated by the drive shaft of the electric motor 8b. The rear of the cylinder 4 and the suction section 5 of the hydraulic pump 8a are connected to each other.

[0024] The battery pack 14b, which supplies power to the control circuit 6 and the electric motor 8b, is connected to the mounting portion 14a of the main body 2, and the mounting portion 14a is connected to the handle portion 2b of the main body 2. The handle portion 2b is a handle that is held by the operator and is provided with a start switch 2c and a return switch 2d. Operating the start switch 2c activates the electric motor 8b and hydraulic pump 8a, sending hydraulic oil 9b to the cylinder 4 and operating the tool head 3. A return flow path is formed inside the cylinder 4 to return the hydraulic oil 9b to the oil tank 7 through a relief valve, and operating the return switch 2d returns the hydraulic oil 9b to the oil tank 7.

[0025] The oil tank 7 is made of rubber or elastomer and is a cylindrical body arranged around the suction portion 5 of the hydraulic pump 8a. The oil tank 7 is made of an oil-resistant and insulating rubber material. For example, the oil tank 7 is made of urethane rubber, acrylonitrile-butadiene rubber, isobutylene-isoprene rubber, butyl rubber, ethylene propylene rubber, styrene-butadiene rubber, fluororubber, or a known oil-resistant and insulating elastomer.

[0026] [Example 1] Fig. 2A is a schematic external view showing an example of the oil tank 7 of the power tool 1 of this embodiment. Fig. 2B is a schematic internal structural view of the oil tank 7 shown in Fig. 2A. Fig. 2C is a schematic internal structural view showing the main parts of a first example of the power tool 1 of this embodiment. The oil tank 7 has a protrusion 11 formed on its inner side facing the suction port 5a. The oil tank 7 has one or more protrusions 11 formed at positions approaching the suction port 5a when hydraulic oil 9b is delivered to the cylinder 4.

[0027] As an example, the width of the protrusion 11 is 0.5 times or less the inner diameter of the suction port 5a. As an example, the length of the protrusion 11 is at least twice the inner diameter of the suction port 5a. As an example, the height of the protrusion 11 is at least 1 time the thickness of the oil tank 7. With this configuration, even if the deformation of the oil tank 7 increases, the oil passage can be secured without blocking the suction port 5a. As an example, the protrusion 11 is formed so as to be in the same direction as or parallel to the axis P1 of the cylinder 4 when the hydraulic oil 9b is filled. With this configuration, the protrusion 11 can be formed in the mold-pulling direction, making it easy to mold the oil tank 7 using a mold.

[0028] [Example 2] Fig. 3A is a schematic diagram of the internal structure showing the main parts of a second example of the power tool 1 of this embodiment. Fig. 3B is a schematic longitudinal cross-sectional view of the suction section 5 of the second example. Fig. 3C is a schematic transverse cross-sectional view of the suction section 5 of the second example when viewed in the direction of the piston 4a from a center line P2 that passes through the center of one of the suction ports 5a and intersects with the axis P1. Hydraulic pump 8a has a step 12 formed in the suction section 5. The suction port 5a is formed across the step 12.

[0029] The hydraulic pump 8a has a plunger 9a arranged around the axis P1 and reciprocating while contacting the swash plate cam. The hydraulic pump 8a has one or more plungers 9a. When hydraulic oil 9b is sent from the hydraulic pump 8a to the cylinder 4, the hydraulic pressure in the cylinder chamber 4b increases, causing the piston 4a to move forward. When the hydraulic oil 9b returns from the cylinder 4 to the oil tank 7, the hydraulic pressure in the cylinder chamber 4b decreases, causing the piston 4a to move backward. The cylinder 4 has a piston 4a arranged in the cylinder chamber 4b, and a coil spring 4c is arranged along the outer periphery of the piston 4a, aligned with the axis of the piston 4a. The hydraulic pump 8a is made of an iron-based material, a titanium-based material, a nickel-based material, or an aluminum-based material. The cylinder 4 is made of an iron-based material, a titanium-based material, a nickel-based material, or an aluminum-based material.

[0030] A check valve 5d that prevents backflow of hydraulic oil 9b to the plunger 9a is disposed at a position on the secondary side of the plunger 9a that communicates with the cylinder chamber 4b. In addition, another check valve 5d that prevents backflow of hydraulic oil 9b to the oil tank 7 is disposed at a position on the secondary side of the plunger 9a closer to the hydraulic pump 8a than the position where the check valve 5d is disposed.

[0031] For example, step 12 is at least one time the thickness of oil tank 7. For example, step 12 is formed so as to intersect center line P2 and surround multiple suction portions 5. This configuration makes it easy to form cylinder 4 by lathe processing.

[0032] [Example 3] Fig. 4A is a schematic internal structural view showing the main parts of a third example of the power tool of this embodiment. Fig. 4B is a schematic longitudinal cross-sectional view of the suction section 5 of the third example. Fig. 4C is a schematic transverse cross-sectional view of the suction section 5 of the third example when viewed in the direction of the piston 4a from a center line P2 that passes through the center of one of the suction ports 5a and intersects with the axis P1. The suction section 5 has a groove-shaped first oil passage 13a formed therein. The first oil passage 13a has a V-groove shape, a U-groove shape, a concave groove shape, or a known groove shape. The first oil passage 13a is formed and connected to the suction port 5a.

[0033] As an example, first oil passage 13a is formed by connecting one of suction ports 5a to another of suction ports 5a in the circumferential direction of hydraulic pump 8a at a position deviated from center line P2 that passes through suction port 5a toward the axis of cylinder 4. With this configuration, groove-shaped first oil passage 13a can be formed in the circumferential direction of hydraulic pump 8a, so that groove-shaped first oil passage 13a can be easily formed by lathe processing.

[0034] [Example 4] FIG. 5A is a schematic diagram of the internal structure of a fourth example of the power tool according to the present embodiment. FIG. 5B is a schematic longitudinal cross-sectional view of the suction section 5 according to the fourth example. FIG. 5C is a schematic transverse cross-sectional view of the suction section 5 according to the fourth example, viewed from a center line P2 that passes through the center of one of the suction ports 5a and intersects with the axis P1, toward the piston 4a. The hydraulic pump 8a has a groove-shaped second oil passage 13b formed in the suction section 5. The second oil passage 13b has a V-groove shape, a U-groove shape, a concave groove shape, or a known groove shape. The second oil passage 13b is formed in the same direction as the axis P1, extending from the suction port 5a to the rear end of the suction section 5. This configuration allows the groove-shaped second oil passage 13b to be easily formed by cutting.

[0035] The above-described embodiment has been described with reference to an example in which the oil tank 7 has linear protrusions 11 on its inner side. However, the present invention is not limited to this example, and the shape of the protrusions 11 may be island-shaped, dot-shaped, or scale-shaped. Furthermore, the present invention is not limited to the application of each embodiment, and each embodiment may be combined and applied. For example, the protrusion 11 of the first embodiment may be combined with the step 12 of the second embodiment. For example, the protrusion 11 of the first embodiment may be combined with the groove-shaped first oil passage 13a of the third embodiment. For example, the step 12 of the second embodiment may be combined with the groove-shaped second oil passage 13b of the fourth embodiment.

[0036] This configuration is not limited to the pistol-type power tool described above, but can be widely applied to portable power tools including straight-type power tools. The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. [Explanation of symbols]

[0037] 1 Power tools 2 Main body, 2a Housing, 2b Handle, 2c Start switch, 2d Return switch 3 Tool Head 4 cylinder, 4a piston, 4b cylinder chamber, 4c coil spring 5. Intake section, 5a. Intake port, 5b. Flow path, 5c. Check valve, 5d. Backflow prevention valve 6 Control Circuit 7. Oil Tank 8a Hydraulic pump, 8b Electric motor 9a Plunger, 9b Hydraulic oil 11 Convex part 12 steps 13a 1st oilway, 13b 2nd oilway 14a Mounting portion, 14b Battery pack P1 axis P2 center line

Claims

1. The tool comprises a rubber or elastomer oil tank, a cylinder, a hydraulic pump for supplying hydraulic oil to the cylinder, a main body having an electric motor for driving the hydraulic pump, and a tool head that is actuated by hydraulic pressure of the cylinder, wherein the hydraulic pump is provided with a suction section for the hydraulic oil and the oil tank is disposed around the suction port of the suction section, and a convex portion is formed on the inside of the oil tank, and the convex portion is formed at a position that approaches the suction port when the hydraulic oil is supplied to the cylinder. A power tool characterized by:

2. The width of the convex portion of the oil tank is 0.5 times or less the inner diameter of the suction port, the length of the convex portion is 2 times or more the inner diameter of the suction port, and the convex portion is formed so as to be in the same direction as the axis of the cylinder when filled with the hydraulic oil. The power tool according to claim 1 .

3. The tool comprises a main body having a rubber or elastomer oil tank, a cylinder, a hydraulic pump that supplies hydraulic oil to the cylinder, and an electric motor that drives the hydraulic pump, and a tool head that operates by hydraulic pressure of the cylinder, wherein the hydraulic pump is provided with a suction section for the hydraulic oil and the oil tank is disposed around the suction port of the suction section, and a step is formed in the suction section, and the suction port is formed across the step. A power tool characterized by:

4. The step is at least one time the thickness of the oil tank, and is formed so as to go around the intake portion while intersecting a center line passing through the intake port toward the axis of the cylinder. The power tool according to claim 3,

5. The tool comprises a main body having a rubber or elastomer oil tank, a cylinder, a hydraulic pump that supplies hydraulic oil to the cylinder, and an electric motor that drives the hydraulic pump, and a tool head that operates by hydraulic pressure of the cylinder, wherein the hydraulic pump is provided with a suction section for the hydraulic oil and the oil tank is disposed around the suction port of the suction section, and a groove-shaped oil passage is formed in the suction section, and the oil passage is formed to be connected to the suction port. A power tool characterized by:

6. The oil passage is formed in the same direction as the axis of the cylinder, extending from the intake port to the rear end of the intake portion. The power tool according to claim 5 .

7. The oil passage is formed in a position deviated from a center line passing through the suction port toward the axis of the cylinder, and extends from one of the suction ports to another of the suction ports in the circumferential direction of the hydraulic pump. The power tool according to claim 5 .

8. The main body has a handle portion on which a start switch for starting the electric motor is disposed, a battery pack for supplying power to the electric motor, and an attachment portion for detachably attaching the battery pack. The power tool according to any one of claims 1 to 7,

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