JP7006298B2 - Driving tool - Google Patents

Description

The present invention relates to a driving tool that burns a mixed gas of air and fuel and is driven by the combustion pressure.

A driving tool called a nail driving machine is known in which a piston is operated by a striking cylinder using compressed air as a power source to drive a driver coupled to the piston to drive a fastener such as a nail. In such a driving tool, a valve called a head valve is configured so that compressed air is supplied from the side of the striking cylinder.

On the other hand, there is known a driving tool called a nail driving machine that burns a mixed gas of air and fuel, operates a striking cylinder with the combustion pressure, and drives a fastener such as a nail. In the gas combustion type driving tool, the combustion pressure can be further increased by burning the mixed gas whose pressure has been increased in advance. However, when compressed air is supplied to the combustion chamber in order to generate a mixed gas having an increased pressure, the striking cylinder is operated by the pressure of the compressed air before the mixed gas is burned.

Therefore, a driving tool provided with a combustion chamber for burning a mixed gas of compressed air and fuel and a valve for partitioning the striking cylinder so as to be openable and closable has been proposed (see, for example, Patent Document 1).

Japanese Patent No. 4935978

Conventionally, the valve that separates the combustion chamber from the striking cylinder so that it can be opened and closed has the same configuration as a driving tool that uses compressed air as a power source, and the high-temperature and high-pressure gas burned from the side of the striking cylinder is supplied. It has become.

In such a configuration, the sealing material is provided on the end face along the moving direction of the valve, but when the valve is open, the sealing material is exposed to the gas flow path. Since the gas obtained by burning the mixed gas of compressed air and fuel has a high temperature and high pressure, when the sealing material is exposed to the gas flow path, the sealing material is affected by heat and its durability is lowered. Further, although a spring is provided to urge the valve in the closing direction, in a configuration in which the high-temperature and high-pressure gas burned from the side of the striking cylinder is supplied, the diameter of the spring becomes large, which leads to an increase in the size of the main body.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a driving tool that improves the durability of the sealed portion and suppresses the increase in size of the main body.

In order to solve the above-mentioned problems, the present invention has a striking mechanism that operates by the combustion pressure of a mixed gas of compressed air and fuel, a combustion chamber that burns a mixed gas of compressed air and fuel, and a striking mechanism and a combustion chamber. It is equipped with a valve body that opens and closes between the valve body and a valve support body that supports the valve body , and the combustion chamber is located in the axial direction of the striking mechanism, includes the valve support body, and has a space around the valve support body. Formed, the valve body is placed in the space inside the valve support, the valve support is provided with a head valve inlet on the side connecting the inner space and the combustion chamber, and the valve body is along the direction of movement. The outer peripheral surface is provided with a seal portion that is in sliding contact with the inner surface of the valve support, and the seal portion is a driving tool provided at a position where the valve body opens the head valve inlet and does not pass through the head valve inlet .

In the present invention, by providing the seal portion on the outer periphery of the valve body that opens and closes between the striking mechanism and the combustion chamber, the seal portion may be exposed to the gas obtained by burning the mixed gas of compressed air and fuel. It is suppressed.

In the present invention, the durability of the seal portion can be improved by a configuration in which a mixed gas of compressed air and fuel is burned and the striking mechanism is operated by the combustion pressure .

It is an overall block diagram which shows an example of the nail driving machine of this embodiment. It is a main part block diagram which shows an example and the operation example of the nail driving machine of this embodiment. It is a main part block diagram which shows an example and the operation example of the nail driving machine of this embodiment.

Hereinafter, an embodiment of a nail driving machine, which is an example of the driving tool of the present invention, will be described with reference to the drawings.

<Structure example of the nail driving machine of this embodiment>
FIG. 1 is an overall configuration diagram showing an example of a nailing machine of the present embodiment, and FIGS. 2 to 3 are a main configuration diagram showing an example of the nailing machine of the present embodiment and an operation example.

The nailing machine 1A of the present embodiment includes a main body portion 10 and a handle portion 11 extending from the main body portion 10 and gripped by hand. The nailing machine 1A includes a nose portion 12 on which a fastener is punched out on one side of the main body portion 10. In the following description, the side where the nose portion 12 is provided is the lower side in consideration of the usage pattern of the nailing machine 1A.

The nailing machine 1A is provided with a tank mounting portion 13 to which a fuel tank (not shown) filled with fuel is detachably attached, in a form substantially parallel to the lower part of the handle portion 11. Further, in the nailing machine 1A, a magazine 14 sharing a fastener with the nose portion 12 is provided below the tank mounting portion 13. Further, in the nailing machine 1A, an air plug 15 to which an air hose to which compressed air is supplied from a supply source such as an air compressor is connected is provided in the tank mounting portion 13 in this example.

Further, in the nailing machine 1A, an operation trigger 16 for operating the nailing machine 1A is provided on the handle portion 11, and a battery mounting portion 18 to which a battery 17 serving as a power source for the nailing machine 1A is attached is provided on the handle portion 11. ..

The nailing machine 1A includes a striking cylinder 2 that operates by the combustion pressure of a mixed gas of compressed air and fuel, a combustion chamber 3 that burns a mixed gas of compressed air and fuel, and a striking cylinder 2 and a combustion chamber 3. A head valve 4 that opens and closes between the head valves 4 and a valve support 5 that supports the head valve 4 are provided.

The striking cylinder 2 is an example of a striking mechanism, and includes a driver 20 for ejecting a fastener supplied from the magazine 14 to the nose portion 12, and a piston 21 provided with the driver 20. The striking cylinder 2 is provided with a cylindrical space in which the piston 21 can slide, and the driver 20 moves along the extending direction of the nose portion 12 by the reciprocating operation of the piston 21.

Further, the striking cylinder 2 includes a cushioning material 22 to which the piston 21 is applied. The cushioning material 22 is made of an elastic member and is provided at the lower part of the striking cylinder 2. In the striking cylinder 2, the moving range of the driver 20 and the piston 21 is restricted by the piston 21 moved by the operation of pushing out the fastener hitting the cushioning material 22.

The combustion chamber 3 is provided in the upper part of the striking cylinder 2 along the axial direction of the driver 20 and the piston 21 which are the axial directions of the striking cylinder 2. The striking cylinder 2 and the combustion chamber 3 are partitioned by a partition portion 50, and the striking cylinder inflow port 51 through which the burned high-temperature and high-pressure air passes is provided in the partition portion 50. The striking cylinder inlet 51 is an example of the striking mechanism inlet, and is configured by providing a circular opening on the shafts of the driver 20 and the piston 21 in the axial direction of the striking cylinder 2.

In the combustion chamber 3, a valve support 5 is provided around the impact cylinder inlet 51, and a ring-shaped space is formed around the valve support 5.

The head valve 4 is an example of a valve body, and is composed of a cylindrical metal member. As shown in FIGS. 2 and 3, in the head valve 4, the lower end surface along the axial direction of the cylinder is closed, and a circular and planar valve surface 40 is formed. The head valve 4 has a valve surface 40 having a diameter larger than that of the striking cylinder inlet 51, and when the valve surface 40 is in contact with the partition portion 50, the striking cylinder inlet 51 is closed.

The head valve 4 includes a first seal portion 41 and a second seal portion 42. The first sealing portion 41 is an example of the sealing portion, and is provided on the outer periphery of the valve surface 40 along the axial direction which is the moving direction of the head valve 4, and the first sealing material 41a is attached. The first sealing material 41a is composed of a metal ring called a piston ring. In the first sealing portion 41, a groove into which the first sealing material 41a is fitted is formed in the circumferential direction, and when the first sealing material 41a is attached, the first sealing material 41a protrudes from the circumferential surface by a predetermined amount. do. In this example, two first sealing materials 41a are attached to the first sealing portion 41 along the axial direction of the head valve 4.

The second sealing portion 42 is an example of a sealing portion, and is provided on the outer periphery of the head valve 4 at a predetermined distance from the first sealing portion 41 along the axial direction of the head valve 4, and is provided as a second sealing material. 42a is attached. The second sealing material 42a is a so-called O-ring made of an elastic body such as rubber. In the second sealing portion 42, a groove into which the second sealing material 42a is fitted is formed in the circumferential direction, and when the second sealing material 42a is attached, the second sealing material 42a protrudes from the circumferential surface by a predetermined amount. do.

In the head valve 4, the first seal portion 41 and the second seal portion 42 project outward from the circumferential surface of the head valve 4, and the second seal portion 42 has a second seal portion 42 with respect to the first seal portion 41. The diameter is large. The surface of the second seal portion 42 facing the first seal portion 41 is an operating surface 43 that is pressed by a high-temperature and high-pressure gas. The working surface 43 is a ring-shaped surface.

The head valve 4 is urged in the direction of the partition portion 50 by the spring 44. The spring 44 is an example of an urging member, and is composed of a coil spring, and the axis of the spring 44 is on the axis of the driver 20 and the piston 21 which are on the axis of the striking cylinder 2, that is, the head valve 4 and the striking cylinder inlet 51. It is provided coaxially. The spring 44 enters the concave portion 45 having an upper opening formed in the head valve 4 along the axial direction which is the moving direction of the head valve 4, so that the head valve 4 and a part of the spring 44 overlap in the axial direction. Will be placed. Such an arrangement is called an overlap arrangement. Further, in order to allow the spring 44 to enter the recess 45 of the head valve 4, the spring 44 has a smaller diameter than the head valve 4, and the spring 44 can have a smaller diameter than the striking cylinder 2.

The force that pushes the head valve 4 by the spring 44 is a force that keeps the valve surface 40 in contact with the partition portion 50 in a state where the high-temperature and high-pressure gas does not act on the operating surface 43.

The head valve 4 is movably supported by the valve support 5.

The valve support 5 is an example of a valve support, and is composed of a cylindrical metal member. As shown in FIGS. 2 and 3, in this example, the valve support 5 is integrally provided with a partition portion 50 at the lower portion along the axial direction of the cylinder. When the head valve 4 is inserted into the space inside the cylindrical shape of the valve support 5, the first sealing material 41a of the first sealing portion 41 of the head valve 4 is in sliding contact with the second sealing portion 42. The second sealing material 42a is in sliding contact. The valve support 5 has each seal at a portion where the first sealing material 41a of the first sealing portion 41 of the head valve 4 is in sliding contact and a portion where the second sealing material 42a of the second sealing portion 42 is in sliding contact. The inner diameter is different according to the part.

When the head valve 4 is inserted in the valve support 5, an operating space 52 is formed between the first seal portion 41 and the second seal portion 42 of the head valve 4 and the inner surface of the valve support 5. The working space 52 is an annular space.

The valve support 5 includes a head valve inlet 53 that connects the combustion chamber 3 and the working space 52. The head valve inflow port 53 is configured by providing an opening penetrating the valve support 5 in the vicinity of the first seal portion 41 in a state where the valve surface 40 of the head valve 4 is in contact with the partition portion 50. To. By forming the head valve inflow port 53 on the side surface of the valve support 5, the flow path connecting the combustion chamber 3 and the working space 52 is not complicated, and an increase in inflow resistance can be prevented.

As shown in FIG. 2, the head valve inflow port 53 is in a state where the valve surface 40 of the head valve 4 is in contact with the partition portion 50, that is, a state in which the impact cylinder inflow port 51 is closed by the head valve 4. Then, it is connected to the working space 52.

On the other hand, when the head valve 4 moves upward due to the action of a high-temperature and high-pressure gas on the operating surface 43 of the head valve 4, the impact cylinder inflow port 51 opens and the head valve inflow port is opened. 53 is connected to the impact cylinder inlet 51.

The air passing through the head valve inlet 53 is high-temperature and high-pressure air generated by burning a mixed gas of compressed air and fuel in the combustion chamber 3. Since the high temperature and high pressure gas has a lower viscosity than the air at normal temperature and pressure, the increase in resistance to the gas flow is suppressed even if the opening area of the head valve inlet 53 is small.

The first sealing material 41a is provided on the outer periphery of the first sealing portion 41, and the first sealing material 41a is in contact with the inner surface of the valve support 5. Since the first sealing material 41a is fitted in the groove, the portion exposed to the working space 52 is minimized.

The second sealing material 42a is provided with a second sealing material 42a on the outer periphery thereof, and the second sealing material 42a is in contact with the inner surface of the valve support 5. Since the second sealing material 42a is fitted in the groove, the portion exposed to the working space 52 is minimized.

The valve support 5 includes a cushioning material 54 to which the head valve 4 is applied. The cushioning material 54 is made of an elastic member and is provided on the upper portion of the head valve 4. In the valve support 5, the moving range of the head valve 4 is restricted by the head valve 4 moving due to the action of a high-temperature and high-pressure gas acting on the operating surface 43 of the head valve 4 and hitting the cushioning material 54. The moving range of the head valve 4 is restricted by the cushioning material 54, but when the head valve 4 hits the cushioning material 54, the impact is absorbed by the elastic deformation of the cushioning material 54, so that the height of the head valve inflow port 53 is increased. , It is preferable to keep the stroke of the head valve 4 or less. As a result, when the head valve 4 moves to the position where it hits the cushioning material 54, the head valve 4 can be prevented from being exposed to the head valve inlet 53, and the entire head valve inlet 53 is opened. In this way, the output can be stabilized by keeping the opening amount of the head valve inlet 53 constant.

The upper opening of the combustion chamber 3 is sealed by the head portion 30. The head portion 30 is provided with an ignition device 31. Further, the head portion 30 is provided with a fuel supply port and a compressed air supply port (not shown). Further, by providing the cushioning material 54 so as to be in contact with the head portion 30, the impact applied to the head portion 30 is buffered, the durability of the parts is improved, the bolts that attach the head portion 30 to the combustion chamber 3 are prevented from loosening, and electrical noise is generated. Effects such as reduction of noise can be obtained.

The nailing machine 1A includes a driver 20 of the striking cylinder 2 and a blowback chamber 6 for storing gas for returning the piston 21. The blowback chamber 6 is provided around the striking cylinder 2 and is connected to the inside of the striking cylinder 2 by an inflow / discharge port 60 provided in the vicinity of the cushioning material 22.

The nailing machine 1A includes a contact member 8 in the nose portion 12. The contact member 8 is provided so as to be movable along the extending direction of the nose portion 12, and is urged by the spring 80 in the direction of projecting from the nose portion 12. The contact member 8 is connected to an exhaust valve (not shown) that opens the combustion chamber 3 to the atmosphere via a link 81, and an exhaust valve (not shown) operates in conjunction with the movement of the contact member 8.

<Operation example of the nail driving machine of this embodiment>
Next, the operation of the nailing machine 1A of the present embodiment will be described with reference to each figure. In the initial state, the operation trigger 16 is not pulled, the contact member 8 is not pushed against the material to be driven, and the contact member 8 is urged by the spring 80 and is in the initial position protruding from the nose portion 12.

When the contact member 8 is in the initial position, the combustion chamber 3 is opened to the atmosphere by an exhaust valve (not shown).

Further, the head valve 4 is in a state where the valve surface 40 is pressed by the spring 44 and is in contact with the partition portion 50, that is, the impact cylinder inflow port 51 is closed by the head valve 4. In this state, the head valve inlet 53 is connected to the working space 52.

When the contact member 8 is pressed against the material to be driven, the movement of the contact member 8 is transmitted to an exhaust valve (not shown) by the link 81, and the combustion chamber 3 is sealed.

Further, in conjunction with the operation of the contact member 8 and the operation trigger 16, an air valve and a fuel valve (not shown) are opened, and vaporized fuel and compressed air are supplied to the combustion chamber 3.

When compressed air is supplied to the combustion chamber 3, the pressure in the combustion chamber 3 rises. However, when the pressure in the combustion chamber 3 rises due to compressed air, the head valve 4 is pressed by the spring 44 to keep the valve surface 40 in contact with the partition portion 50, and the impact cylinder inflow port 51 is closed by the head valve 4. Be done. Therefore, even if the pressure inside the combustion chamber 3 rises due to the supply of compressed air, the pressure rise does not occur in the striking cylinder 2, and the piston 21 does not operate.

After the contact member 8 is pressed against the material to be driven and the operation trigger 16 is operated to open the air valve and the fuel valve (not shown), when the ignition device 31 is operated at a predetermined timing, the compression in the combustion chamber 3 is performed. A mixed gas of air and fuel burns. When the mixed gas burns in the combustion chamber 3, the pressure in the combustion chamber 3 rises, and the high-temperature and high-pressure gas flows into the working space 52 from the head valve inlet 53 of the head support 5.

When the pressure in the working space 52 rises, a high-temperature and high-pressure gas acts on the working surface 43 of the head valve 4, so that the head valve 4 moves upward while compressing the spring 44. Here, when the pressure in the working space 52 rises, the pressure is also applied to the surface of the first seal portion 41 facing the working space 52. However, since the working surface 43 has a larger area, the head valve 4 rises while compressing the spring 44.

As shown in FIG. 3, when the head valve 4 moves upward, the striking cylinder inlet 51 opens, and the head valve inlet 53 is connected to the striking cylinder inlet 51. As a result, the high-temperature and high-pressure gas flows from the combustion chamber 3 through the striking cylinder inlet 51 into the striking cylinder 2, and the pressure of the striking cylinder 2 rises.

When the pressure of the striking cylinder 2 rises, the piston 21 is pushed, the piston 21 and the driver 20 move in the direction of launching the fastener, and the fastener driving operation is performed. When the piston 21 and the driver 20 move in the direction of launching the fastener, the lower gas (air) in the striking cylinder 2 partitioned by the piston 21 flows into the blowback chamber 6 from the inflow / discharge port 60. Further, since the piston 21 passes through the inflow / discharge port 60 while compressing and deforming the cushioning material 22, a part of the high-temperature and high-pressure gas that drives the piston 21 flows into the blowback chamber 6.

High-temperature and high-pressure gas flows from the combustion chamber 3 into the striking cylinder 2 through the striking cylinder inlet 51, and the pressure in the combustion chamber 3 drops, so that the head valve 4 is pressed by the spring 44 and the valve surface 40. Moves to a position in contact with the partition portion 50, and the impact cylinder inflow port 51 is closed by the head valve 4.

Further, when the piston 21 and the driver 20 move in the direction of launching the fastener and the piston 21 moves to the bottom dead center and hits the cushioning material 22, the piston 21 and the driver 20 tend to move upward due to the elasticity of the cushioning material 22. .. When the piston 21 passes through the inflow / discharge port 60 and moves to the upper side of the inflow / discharge port 60, the gas (air) in the blowback chamber 6 where the pressure is increasing flows into the striking cylinder 2 and pushes the piston 21. As a result, the piston 21 and the driver 20 return to the top dead center.

When the contact member 8 separates from the material to be driven, an exhaust valve (not shown) opens and the combustion chamber 3 is opened to the atmosphere.

In the nailing machine 1A of the present embodiment, compressed air and fuel are supplied to the combustion chamber 3 and a high-pressure gas is generated by burning the mixed gas, and the high-pressure gas pushes the piston 21 of the striking cylinder 2. As a result, the force for pushing the fastener with the piston 21 and the driver 20 becomes stronger.

As a result, the output for driving the fastener can be increased as compared with the conventional gas combustion type nailing machine using a gas at normal pressure.

Further, by providing a head valve 4 for opening and closing the striking cylinder inlet 51 between the combustion chamber 3 and the striking cylinder 2, the striking cylinder 2 is prevented from operating only by supplying compressed air to the combustion chamber 3. be able to. Further, by operating the head valve 4 with the combustion pressure of the mixed gas, a separate power source for driving the head valve 4 is not required. As a result, the structure of the head valve 4 and its drive mechanism can be simplified, and the size and cost of the device can be reduced.

Further, the combustion chamber 3 is provided in the upper part of the striking cylinder 2 along the axial direction of the driver 20 and the piston 21, so that the volume of the combustion chamber 3 is compared with the structure in which the combustion chamber is provided around the striking cylinder 2. The diameter of the combustion chamber 3 can be reduced without reducing the size of the combustion chamber 3. Since the inside of the combustion chamber 3 becomes high pressure, it is necessary to give strength to the combustion chamber 3, but since the diameter of the combustion chamber 3 can be reduced, the strength can be secured even if the combustion chamber 3 is made thinner. It is possible to reduce the size and weight of the entire device.

Further, the striking cylinder inlet 51 connecting the combustion chamber 3 and the striking cylinder 2 is provided on the shafts of the driver 20 and the piston 21, so that the striking cylinder inlet 51 can be made smaller in diameter than the striking cylinder 2, and as a result, the head valve. 4 can be made smaller in diameter than the striking cylinder 2. Since the diameter of the head valve 4 can be reduced, the moving speed of the head valve 4 can be improved, and the time required to open the impact cylinder inlet 51 can be shortened.

Further, since the gas that operates the head valve 4 has a high temperature and high pressure, the viscosity is low as compared with the case where the gas at normal pressure is burned. As a result, it is possible to reduce the diameter of the head valve inlet 53 through which the gas that operates the head valve 4 passes, and it is possible to reduce the diameter of the peripheral structures of the combustion chamber 3 and the head valve 4.

The first sealing portion 41 provided on the head valve 4 is provided with a first sealing material 41a on the outer periphery thereof, and the first sealing material 41a is in contact with the inner surface of the valve support 5. Since the first sealing material 41a is fitted in the groove, the portion exposed to the working space 52 is minimized. When the head valve 4 opens the striking cylinder inlet 51 and the head valve inlet 53, high-temperature and high-pressure gas wraps around from the striking cylinder inlet 51 below the head valve 4, but the first sealing material 41a has a groove. Since it is fitted in, the exposed part is minimized.

When the high temperature and high pressure gas acts on the operating surface 43 of the head valve 4, the head valve 4 opens the striking cylinder inlet 51 and the head valve inlet 53, and the first seal portion 41 causes the head valve flow. As it passes through the inlet 53, the first sealing material 41a is exposed to a high temperature and high pressure gas. However, since the first sealing material 41a is made of metal, it is possible to prevent the first sealing material 41a from being affected by heat.

Further, the second sealing material 42a is provided with a second sealing material 42a on the outer periphery thereof, and the second sealing material 42a is in contact with the inner surface of the valve support 5. Since the second sealing material 42a is fitted in the groove, the portion exposed to the working space 52 is minimized.

Since the high temperature and high pressure gas acts on the operating surface 43 of the head valve 4, the exposure of the second sealing material 42a is suppressed even when the head valve 4 opens the head valve inlet 53, so that the second sealing material 42a is suppressed. The sealing material 42a is suppressed from being affected by heat. Further, when the head valve 4 opens the head valve inlet 53, the second seal portion 42 does not pass through the head valve inlet 53, so that the second seal material 42a is suppressed from being exposed to a high temperature and high pressure gas. Will be done.

Therefore, the durability of the sealing material is improved, and the desired performance can be maintained even after long-term use. Further, since one of the sealing materials (first sealing material 41a) of the head valve 4 is made of metal, friction with the valve support 5 is reduced, and the head valve 4 is made smaller in diameter. The movement speed of 4 can be improved. Further, even when the head valve 4 uses a sealing material made of metal, the sealing material is arranged on the end face along the moving direction of the head valve 4 so as to be exposed to the gas flow path. , The durability of the seal portion can be improved to some extent.

However, when a sealing material made of metal is used, a higher contact pressure is required as compared with the case where an elastic sealing material such as rubber is used, so that a high load spring must be used. Therefore, in the nailing machine 1A of the present embodiment, by arranging the spring 44 on the same axis as the head valve 4 which is the center of the head valve 4, the high load spring can be used without increasing the size of the main body 10. It is possible to use. Further, by forming a recess 45 in the axial direction of the head valve 4 and arranging them so as to overlap each other so that the spring 44 can enter, the amount of the spring 44 protruding from the head valve 4 can be reduced, and the amount of the spring 44 protruding from the head valve 4 can be reduced in the height direction of the main body 10. It is possible to suppress the increase in size. Further, since the spring 44 is made to enter the recess 45 of the head valve 4, the diameter of the spring 44 can be made smaller than that of the striking cylinder 2, and it is possible to suppress the increase in the radial dimension of the main body portion 10.

1A ... Nailer, 10 ... Main body, 11 ... Handle, 12 ... Nose, 13 ... Tank mounting, 14 ... Magazine, 15 ... Air plug, 16 ... operation trigger, 17 ... battery, 18 ... battery mounting part, 2 ... striking cylinder (striking mechanism), 20 ... driver, 21 ... piston, 22 ... cushioning material, 3 ... Combustion chamber, 30 ... Head part, 31 ... Ignition device, 4 ... Head valve (valve body), 40 ... Valve surface, 41 ... First seal part, 41a ... 1st sealing material, 42 ... 2nd sealing part, 42a ... 2nd sealing material, 43 ... working surface, 44 ... spring, 45 ... concave, 5 ... .. Valve support (valve support), 50 ... partition, 51 ... striking cylinder inlet (impact mechanism inlet), 52 ... working space, 53 ... head valve inlet, 54 ... Buffer material, 6 ... Blowback chamber, 60 ... Inflow / discharge port, 8 ... Contact member, 80 ... Spring, 81 ... Link

Claims (7)

A striking mechanism operated by the combustion pressure of a mixed gas of compressed air and fuel,
A combustion chamber that burns a mixed gas of compressed air and fuel,
A valve body that opens and closes between the striking mechanism and the combustion chamber,
With a valve support that supports the valve body
Equipped with
The combustion chamber is located in the axial direction of the striking mechanism, includes the valve support, and a space is formed around the valve support.
The valve body is placed in the space inside the valve support, and the valve body is placed in the space inside the valve support.
The valve support is provided with a head valve inlet connecting the inner space and the combustion chamber on the side surface.
The valve body is provided with a sealing portion that is in sliding contact with the inner surface of the valve support on the outer peripheral surface along the moving direction.
The seal portion is provided at a position where the valve body does not pass through the head valve inlet when the valve body opens the head valve inlet.
Driving tool. The seal portion is a first seal portion to which a first metal sealing material that is in sliding contact with the inner surface of the valve support is attached, and the valve body is an operation of opening the head valve inlet, and the head valve flow. The driving tool according to claim 1, further comprising a second sealing portion provided at a position not passing through the inlet and to which a second sealing material composed of an elastic body sliding in contact with the inner surface of the valve support is attached . The partition portion that separates the striking mechanism from the combustion chamber is provided with a striking mechanism inlet that allows gas to flow from the combustion chamber into the striking mechanism.
The driving tool according to claim 1 or 2 , wherein the striking mechanism inlet is provided with an opening having a diameter smaller than that of the piston of the striking mechanism in the axial direction of the striking mechanism . The driving tool according to any one of claims 1 to 3 , wherein the coil spring for urging the valve body is provided on the axis of the driver of the striking mechanism . The driving tool according to claim 4 , wherein the coil spring enters a recess formed in the valve body along the moving direction of the valve body . The coil spring has a smaller diameter than the piston of the striking mechanism.
The driving tool according to claim 4 or 5 . The driving according to any one of claims 4 to 6 , wherein the valve body has a cylindrical shape, has a smaller diameter than the piston of the striking mechanism, and is provided inside the combustion chamber along the axial direction of the striking mechanism. tool.

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