JP4276449B2 - Throttle valve for air tool - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a throttle valve for an air tool such as an impact wrench, a pulse wrench, a driver, and a drill. In particular, the present invention relates to a throttle valve that can be operated with a small force and that can adjust the rotational speed of an air motor stepwise.
[0002]
[Background Art and Problems to be Solved by the Invention]
As a conventional throttle valve that adjusts the rotational speed of an air motor of an air tool such as an impact wrench step by step, there is the following. (See patent literature)
[0003]
The valve has a substantially cylindrical throttle body having a main air intake opening at one end, a valve body having an auxiliary air intake opening coaxially with the throttle body and opening and closing the main air intake opening of the throttle body, It is provided coaxially with the throttle body so as to be able to advance and retreat in the axial direction, opens and closes the auxiliary air intake, and has a throttle rod that moves the valve body to open and close the main air intake. An O-ring insertion groove that closes the air intake and an air passage that communicates with the throttle valve body are formed, and an O-ring having a thickness smaller than the width of the insertion groove is inserted. Is supplied.
[0004]
In this throttle valve, when the throttle rod slightly moves, a gap is formed between the O-ring and the O-ring insertion groove. The air supplied from the air supply source enters the fitting groove through the generated gap, and this air is taken into the throttle valve through the air passage. The air motor starts rotating at a very low speed due to the air taken in.
[0005]
Further, when the throttle rod moves, the O-ring moves away from the auxiliary air intake port, air is taken into the throttle valve from the auxiliary air intake port, and the rotation of the air motor is reduced from a very low speed to a low speed. Thereafter, as the throttle lot moves, the valve body moves away from the main air intake, the main air intake opens, and the rotation of the air motor increases from low speed to high speed.
[0006]
[Patent Literature]
Japanese Patent Laid-Open No. 11-58265 (refer to claim 1, FIGS. 2 to 5 and FIG. 7)
[0007]
In such a throttle valve, a differential pressure that is the difference between the pressure inside the throttle valve and the pressure outside the slot valve acts on the O-ring of the valve body and the throttle rod. This differential pressure presses the valve body against the throttle body and the O-ring against the valve body. When opening the valve, the throttle valve must be operated against the pressure difference between the differential pressure and the atmospheric pressure and the air supplied from the air supply source. By the way, the pressure difference between the atmospheric pressure and the air supply source is constant, and the operating force of the throttle valve varies depending on the differential pressure that is the difference between the pressure inside the throttle valve and the pressure outside the slot valve. When the air motor is rotated at a very low speed and a low speed, the opening area of the auxiliary air intake is small, so that the force required to operate the throttle valve is not so great regardless of the differential pressure.
[0008]
On the other hand, when switching the rotation of the air motor from low speed to high speed, it is necessary to take in a large amount of air, the opening area is large, and it is greatly affected by the differential pressure. In other words, the air taken into the throttle valve during low-speed rotation is very small, and the differential pressure is almost the same as when the motor is stopped. Therefore, the force that operates the throttle valve when switching the rotation of the air motor from low to high is significantly increased. . This power is not too small for adult boys.
[0009]
By the way, in order to reduce the fatigue of the operator who operates the throttle valve, it is preferable that the force for operating the throttle valve is smaller. Especially when working for a long time, the operating force of the throttle valve becomes a big problem.
[0010]
An object of the present invention is to solve the above-described problems, and to provide a throttle valve with a small operating force.
[0011]
[Means for Solving the Problems and Effects of the Invention]
To solve the above problem,
A substantially cylindrical throttle body with a main air intake opening at one end, a valve body that opens and closes the main air intake opening of the throttle body and is coaxial with the throttle body, and is coaxial with the throttle body There is a throttle rod that opens and closes in the axial direction and opens and closes the auxiliary air intake and moves the valve body to open and close the main air intake. In a throttle valve for an air tool that is first opened and the valve body is moved by further movement of the throttle rod in the axial direction to open the main air intake port, the valve body in the closed state is positioned with respect to a plane perpendicular to the rod axial direction. And a valve tilting means for opening a part of the main air intake by tilting.
[0012]
In this throttle valve, when the valve body is tilted by pressing only one point on the diameter of the valve body, the valve body tilts with a point on the same diameter as the pressed portion serving as a fulcrum. That is, when the valve body is tilted, the lever principle works. Compared to the force required to move the entire valve body in the axial direction to open the main air intake, The force required to open a part is smaller. When the valve body is tilted, a larger amount of air than the air taken in from the auxiliary air intake is taken into the throttle valve from the main air intake, and the pressure inside the throttle valve and the pressure outside the throttle valve are almost equal. It becomes equal and the differential pressure decreases. For this reason, after the valve body is inclined, the force for moving the valve body is very small.
[0013]
In the above throttle valve,
A valve tilting means is formed on the cylindrical valve body pressing member fitted on one end side of the throttle rod, a radial protrusion protruding radially from one end of the valve body pressing member, and a radial protrusion formed on the radial protrusion. An axial protrusion that abuts the body may be provided.
[0014]
In this way, the valve tilting means can be configured easily.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a throttle valve for an air tool according to an embodiment of the present invention will be described with reference to FIGS. In the following description, the left in FIG. 1 is the front and the right is the rear.
[0016]
FIG. 1 shows a cross section of an air tool 2 to which an air tool throttle valve 1 of the present invention is applied. The throttle valve 1 is disposed in the upper part of the grip 2 a of the air tool 2. The lower part of the grip 2a is connected to an air supply source (not shown), and the air supplied from the lower part of the grip 2a is supplied via the throttle valve 1 to the air motor 3 accommodated in the air tool body 2b. . Further, after the throttle valve 1, a spring 4 for biasing the throttle valve 1 in the closing direction is disposed.
[0017]
FIG. 2 shows a cross section of the throttle valve 1 in the closed state. Hereinafter, the configuration of the throttle valve 1 will be described mainly with reference to FIG.
[0018]
The throttle valve 1 has a substantially cylindrical shape extending in the front-rear direction, the front and rear ends are open, and the rear end opening is a main air intake 5a, and the throttle body 5 is disposed in the throttle body 5 and the front end opening of the throttle body 5 is opened. A valve bush 6 that is closed, a throttle rod 7 that is arranged coaxially with the throttle body 5 and penetrates the throttle body 5 and the valve bush 6 so as to freely advance and retract, and a portion that protrudes rearward from the valve bush 6 in the throttle rod 7 In addition, a cylindrical valve body pushing member 8 fitted over a portion located in the throttle body 5 and an auxiliary air intake opening that closes the main air intake opening 5a and penetrates the rear portion of the throttle rod 7 are opened. A short cylindrical valve body 9 is provided.
[0019]
An air supply port 5 b for supplying air to the air motor 3 is opened in the upper peripheral wall of the throttle body 5. The air supply port 5 b is for supplying the air guided from the air intake port 5 a to the inside of the throttle body 5 to the air motor 3.
[0020]
A front end portion of the throttle rod 7 protrudes outside the grip 2a of the tool 2, and a throttle lever 12 is attached to the front end of the protruding portion. The diameter of the portion of the throttle rod 7 that protrudes rearward from the valve bush 6 is smaller than that of the other portion (hereinafter, this portion is referred to as a small diameter portion and a symbol 7a, and the other portion is referred to as a large diameter portion. 7b). Furthermore, an annular groove is formed in a portion of the small diameter portion 7a of the throttle rod 7 that protrudes rearward from the valve body 9, and an O-ring 13 for closing the auxiliary air intake is fitted into the annular groove.
[0021]
An annular groove is formed behind the O-ring 13, and a ring-shaped member 14 is fitted in the annular groove. A low-speed air intake recess 7e extending in the axial direction is formed on the front side of the portion where the O-ring 13 is fitted in the small diameter portion 7a of the throttle rod 7. A notch 7f communicating with the recess 7e is formed at the rear end of the large diameter portion 7b of the throttle rod 7.
[0022]
As shown in FIG. 2, the length of the valve body pressing member 8 is shorter than the distance between the rear end surface of the large-diameter portion of the throttle rod 7 and the front end surface of the valve body 9 in the closed state. There is a slight gap between the end surface and the front end surface of the pressing member 8. As shown in FIG. 3, the pressing member 8 includes a radial protrusion 8a protruding radially from the rear end thereof, and a rear protrusion 8b formed at the tip of the radial protrusion 8a. Yes.
[0023]
The valve body 9 has a short cylindrical shape including a front small-diameter portion 9a and a rear large-diameter portion 9b, and an axial auxiliary air intake 9c is opened at the center. In addition, an annular recess is formed in the outer peripheral portion between the two portions 9a and 9b, and an O-ring 15 for closing the main air intake is fitted in the annular recess. The diameter of the small diameter portion 9a of the valve body 9 is slightly smaller than the diameter of the main air intake 5a, and an annular gap is formed between the small diameter portion 9a and the intake 5a, so that the small diameter portion 9a is the main air of the throttle body 5. When in the intake port 5a, the valve body 9 can be tilted with respect to a plane perpendicular to the axial direction. In addition, the relationship between the diameter of the auxiliary air intake 9c of the valve body 9 and the diameter of the small diameter portion of the rod 7 is similar to the above, so that the valve body 9 is inclined with respect to the diameter of the auxiliary air intake 9c. The diameter is slightly smaller. The rear end of the rear protrusion 8b of the valve main body pressing member 8 is in contact with a part of the periphery of the small diameter portion 9a of the valve main body 9.
[0024]
The throttle valve 1 configured as described above operates as follows to supply air to the air motor 3 and shut off the air.
[0025]
In the state shown in FIG. 2, the O-ring 13 is pressed against the auxiliary air intake 9c of the valve body 9 and the O-ring 15 is pressed against the main air intake 5a by the air pressure outside the throttle valve 1 and the spring 4. Both the auxiliary air and the main air intake are closed.
[0026]
If the lever 12 is pushed from this state to move the rod 7 backward, the O-ring 13 is separated from the auxiliary air intake 9c. Then, the air outside the throttle valve 1 is guided into the throttle valve 1 through the recess 7e and the notch 7f. This air is supplied from the air supply port 5b to the air motor 3, and the air motor 3 starts rotating at a low speed.
[0027]
Further, when the rod 7 is moved rearward, as shown in FIGS. 4 and 5, the rear end surface of the large-diameter portion 7b of the rod 7 hits the front end of the valve pressing member 8 and pushes the valve pressing member 8 backward. The rear end of the rear protrusion 8 b of the pressing member 8 hits the front surface of the valve body 9. When the rod 7 is further moved rearward from this state, the valve body 9 is pushed by the protrusion 8b of the valve pushing member 8 and tilts as shown in FIGS. At this time, as shown in FIGS. 5 and 7, the valve body 9 uses a point of the O-ring 15 as a fulcrum (symbol A in the figure) and contacts the rear protrusion 8 b of the pressing body 8 with the valve body 9. The contact is tilted as a force point (symbol F in the figure). Thus, until the valve body 9 reaches the maximum inclination state shown in FIG. 7 from the state shown in FIG. 5, the valve body 9 is inclined with a small force by the lever principle.
[0028]
When the valve body 9 is tilted, the portion of the O-ring 15 corresponding to the pressed valve body 9 is separated from the peripheral edge of the air intake 5a, and a part of the main air intake 5a is opened. Then, air is taken into the throttle valve 1. The intake air is more than the air entering the throttle valve 1 through the low-speed air intake recess 7e, and the pressure inside the throttle valve 1 and the pressure outside the throttle valve 1 are almost the same. For this reason, the differential pressure applied to the throttle valve 1 is extremely small. Therefore, after the valve main body 9 reaches the maximum inclination state shown in FIG. 6, the force to move the valve main body 9 in the axial direction in parallel with the inclination is the force necessary for contracting the spring 4 and the throttle rod 7. This is a force due to the pressure difference between the atmospheric pressure applied to the cross-sectional area of the large diameter portion 7b and the air supplied from the air supply source. For this reason, the valve main body 9 is moved with a small force to separate the entire O-ring 15 from the main air intake 5a and completely open the main air intake 5a, as shown in FIG. When the main air intake 5a is completely opened, the air motor 3 rotates at a high speed.
[0029]
In order to cut off the supply of air from the throttle valve 1 to the air motor 3, it is only necessary to stop pressing the throttle lever 12. If the pushing is stopped, the throttle rod 7 is pushed forward by the force of the spring 4 and the force due to the pressure difference between the atmospheric pressure and the air supplied from the air supply source. When the throttle rod 7 is pushed forward, the O-ring 13 comes into contact with the peripheral edge of the auxiliary air intake 9c of the valve body 9 and the auxiliary air intake 9c is closed. The throttle rod 7 is further pushed forward by the force of the spring 4 and the force due to the pressure difference between the atmospheric pressure and the air supplied from the air supply source. When the throttle rod 7 is pushed further forward, the valve body 9 is pushed together with the throttle rod 7, the main air inlet 5 a is closed by the O-ring 15 of the valve body 9, and the supply of air to the air motor 3 is performed. Completely blocked.
[0030]
In addition, embodiment of this invention is not restricted to said thing, Each part structure can be changed suitably. For example, in the above-described embodiment, the valve body tilts with a part of the O-ring as a fulcrum, but the valve may tilt with a part of the valve body as a fulcrum.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an air tool to which a throttle valve for an air tool according to an embodiment of the present invention is applied.
FIG. 2 is a longitudinal sectional view when the auxiliary air intake and the main air intake of the throttle valve are in a closed state.
3A is a longitudinal sectional view of a valve pressing member, and FIG. 3B is a front view of the pressing member.
4 is a view corresponding to FIG. 2 when the auxiliary air intake port of the throttle valve is open and the main air intake port is closed. FIG.
FIG. 5 is an enlarged view of a main part of FIG. 4;
FIG. 6 is a longitudinal sectional view showing a state in which a main air intake port of the throttle valve is partially opened.
7 is a view corresponding to FIG. 6 in a partially opened state of the main air intake port of the throttle valve.
FIG. 8 is a longitudinal sectional view of the main air intake port of the throttle valve in an open state.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Throttle valve 2 Air tool 2a Grip 2b Air tool main-body part 3 Air motor 4 Spring 5 Throttle body 5a Main air inlet 5b Air supply port 6 Valve bush 7 Throttle rod 7a Small diameter part 7b Large diameter part 7e Low speed air intake recessed part 7f Notch 8 Cylindrical valve body pressing member 8a Radial protrusion 8b Rear protrusion (axial protrusion)
9 Valve body 9a Small diameter portion 9b Large diameter portion 9c Auxiliary air intake 12 Throttle lever 13 O-ring 14 Ring-shaped member 15 O-ring

Claims (3)

A substantially cylindrical throttle body with a main air intake opening at one end;
A valve body that opens and closes the main air intake of the throttle body and has an auxiliary air intake opened coaxially with the throttle body;
A throttle rod is provided coaxially with the throttle body so as to be able to advance and retreat in the axial direction, opens and closes the auxiliary air intake and moves the valve body to open and close the main air intake.
In the throttle valve for an air tool, the auxiliary air intake is opened by the movement of the throttle rod in the axial direction, and the valve body is moved by the movement of the throttle rod in the axial direction to open the main air intake.
A throttle valve for an air tool provided with a valve tilting means for opening a part of a main air intake by tilting a valve body in a closed state with respect to a plane perpendicular to the rod axis direction. The valve tilting means includes a tubular valve body pressing member that is fitted on one end side of the throttle rod and is moved in the axial direction by the movement of the throttle rod,
A tubular valve body pressing member, a radial protrusion protruding radially from one end of the pressing member;
The throttle valve for an air tool according to claim 1, further comprising an axial protrusion formed on the radial protrusion, wherein the axial protrusion pushes the valve body and tilts the valve body. The throttle valve for an air tool according to claim 2, wherein one end portion of the throttle rod on which the tubular valve body pressing member is fitted has a smaller diameter than the other portion.

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