JP4249734B2 - Air impact wrench - Google Patents

Description

  The present invention relates to an air impact wrench used for operations such as tightening and loosening bolts and nuts.

This type of air impact wrench has an air motor part and a hammer part in the main body, supplies compressed air to the air motor part to generate rotational torque, transmits this rotational torque to the hammer part, and from this hammer part to the anvil It is configured to transmit the impact torque in the rotational direction and tighten or loosen bolts and nuts with a tool (socket-shaped or bit-shaped) attached to the tip of the anvil.
The handle of this type of air impact wrench is made up of a series of gripping parts at the projecting ends of the upper and lower legs projecting straight from the rear end surface of the main body toward the rear. The first type attached to the rear end face of the substantially U-shape or D-shape and the first type attached to the pistol type as a whole by projecting sideways (downward) on the middle side surface (lower surface) in the central axis direction of the main body It is roughly divided into two types.

In the first type, the air hose connection port for supplying air to the air motor portion is formed downward at the lower end of the grip portion of the handle. Further, in the second type, it is formed downward at the lower end of the handle (see, for example, Patent Document 1).
Japanese Utility Model Publication No. 61-117673

In this type of air impact wrench, the operator grips the main handle with his dominant hand and the auxiliary handle provided on the main body with the other hand to perform tightening and loosening work, The start lever that supplies and stops the compressed air to the air motor part is formed on the grip part of the main handle that is gripped by the dominant hand of the operator, and the operator handles the main handle. The start lever can be operated with the index finger or the like of the dominant hand while holding the handle.
Against this background, a start valve that is controlled to open and close by a start lever is also incorporated in the main handle, and an air passage for supplying compressed air to the installation portion of the start valve is also formed in the main handle. The air hose connection port for supplying compressed air to the air passage is formed at the end of the main handle.

  In the conventional first type, since the air hose connection port for air supply is formed downward at the lower end of the grip portion of the main handle attached to the rear end surface of the main body in a substantially U shape or D shape, The air hose connected to the connection port is derived from a position that is greatly decentered in the radial direction of the main body from the central axis of the main body, and is connected to a compressed air supply source such as a rear compressor. For this reason, when the air hose hangs downward from the rear end of the main body and is connected to the rear, the work is tightened or loosened with the main body twisted to the left or right around its central axis (This is not the case in many cases.) The restoring moment around the main axis of the main body due to the weight of the air hose increases, making it difficult to work, requiring a large operating force and increasing the degree of fatigue, and the air hose from the main axis of the main body to the main body Therefore, there is a problem that the air hose is easily damaged and the air hose is easily damaged. In the first conventional type, for example, an air supply hose connection port may be formed on the rear end surface of the main body. In this case, however, the air hose overlaps and interferes with the main handle. There are problems such as obstructing the gripping of the air and needing to bypass the air hose.

Even in the second type, there are the same problems as in the first type.
The present invention has been developed in view of the above-described problems of the conventional air impact wrench. The purpose of the present invention is to connect the air hose for supplying air to the main body so as not to hinder the work, and the main body is easy to hold. It is to provide an air impact wrench that can be operated easily and stably, and that can improve operability and reduce fatigue.

In order to achieve the above object, the present invention includes an air motor portion and a hammer mechanism portion in a main body, and a rotational torque is supplied to the air motor portion by switching between a forward rotation direction and a reverse rotation direction via a left / right switching valve. This torque is transmitted to the hammer mechanism, the hammering torque is transmitted from the hammer mechanism to the anvil, and the bolts and nuts are tightened or loosened with a tool attached to the tip of the anvil. In air impact wrench,
On the rear end surface of the main body, there is a series of main handles consisting of upper and lower leg portions that protrude obliquely rearward with respect to the central axis of the main body and a grip portion formed between the protruding ends of the upper and lower leg portions. The grip portion is attached to one side of the center axis of the main body with an offset, and an air hose connection port for supplying air to the air motor portion is provided on the rear end surface of the main handle. It is characterized by being formed so as not to overlap.

According to the above configuration, the air hose for supplying air is straight from the rear end surface of the main body along the central axis of the main body without being obstructed by the main handle even though the main handle is provided on the rear end surface of the main body. To the rear. This prevents the air supply hose from being bent excessively, and can also avoid collisions with surrounding members and scratches. Therefore, tightening or loosening bolts and nuts in tight spaces In this case, the air hose for supplying air does not hinder the work.
In addition, an air discharge port is formed in the rear end surface of the main body so as not to overlap with a grip portion of the main handle.

Furthermore, a silencer or a discharge hose can be connected to the air discharge port.
According to the above configuration, since the air discharge port is formed on the rear end surface of the main body so as not to overlap the main handle, the main handle can be connected even when the silencer is connected or the discharge hose is connected. Without interfering with each other and without protruding from the outer periphery of the main body, it is possible to avoid interference with peripheral members.

  According to the present invention, the air impact can be connected to the main body so that the air supply hose does not hinder the work, the main body is easy to hold, can be operated easily and stably, and the operability is improved and the fatigue is reduced. A wrench can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 3, reference numeral 1 denotes a main body, the central portion is a motor case 2, the front portion is a hammer case 3, the rear portion is a control case 4, and each case is a central axis in the front-rear direction of the main body 1. The seal rings 5 and 6 made of an elastic material such as rubber are fitted to each joint portion along the longitudinal direction.
On one side of the control case 4 (on the left side for right-handed use in FIGS. 1 to 3, the main handle 7 is on the right side for left-handed use) with respect to the central axis S of the main body 1. A gripping portion 10 is formed in series between the protruding ends of the upper and lower leg portions 8 and 9 that protrude obliquely toward the rear side.

Further, the auxiliary handle 11 is attached so as to protrude to one side of the hammer case 3. The main handle 7 and the auxiliary handle 11 are attached by being offset to the same side with respect to the central axis S of the main body 1, and the operator operates the main handle 7 with the right hand and the auxiliary handle 11 with the left hand. I can do it.
On the lower surface of the control case 4, a left / right switching lever 12 is mounted so as to be rotatable around an axis T perpendicular to the central axis S of the main body 1 within a range of 45 ° to the left and right. The left / right switching lever 12 also serves as a lever for adjusting the supply amount of compressed air, and illustrates a case where adjustment is possible in three stages.

In the vicinity of the upper end of the grip portion 10 of the main handle 7, a start lever 13 is pivotally mounted around the support shaft 14 so as to be rotatable within a certain angle range.
On the rear end surface of the control case 4, an air supply hose connection port 15 and an air discharge port 16 are formed side by side with the latter up and the former down. These arrangements may be upside down, and may be arranged side by side or diagonally. In any case, these air supply air hose connection port 15 and air discharge port 16 are formed in a positional relationship so as not to overlap the main handle 7 and in particular not to overlap the grip portion 10 of the main handle 7. ing.

Next, the internal structure of the main body 1 will be described with reference to FIG.
In the motor case 2, an air motor 17 is supported via a rotor shaft 18 so as to be rotatable about a longitudinal axis (center axis S) of the main body 1. As shown in FIGS. 4 and 5, the air motor 17 forms an eccentric cylindrical space 22 by a cylindrical cylinder 19 and end plates 20 and 21 before and after the cylinder 19, and a cylindrical body shape is formed in the space 22. The rotor 23 is rotatably supported in an eccentric state via the rotor shaft 18, and the rotor blades 24 are fitted in the circumferentially equidistant positions of the rotor 23 so as to be protruded and retracted radially outward. ing.

As shown in FIG. 5, the cylinder 19 is formed with a right rotation air introduction port 25, a left rotation air introduction port 26, and an exhaust port 27 penetrating inward and outward in the radial direction. On the other hand, the right rotation air introduction port 25 and the left rotation air introduction port 26 are formed symmetrically with each other.
Both ends of the cylinder 19 are fitted in the motor case 2 including the end plates 20 and 21. The motor case 2 is shaped to expand rearward, and the rear end wall portion 2a has two left and right sides. Divided air introduction passages 28 and 29 and one exhaust passage 30 are formed. The two air introduction passages 28 and 29 pass through the space formed between the cylinder 19 and the motor case 2 to the left and right rotation air introduction ports 25 and 26, and the exhaust passage 30 includes the exhaust port 27. Are connected to each other.

As shown in FIG. 4, the front end portion of the rotor shaft 18 protrudes into the hammer case 3, and a spline joint 31 is spline-fitted to the front end portion of the rotor shaft 18. On the outer periphery of the spline joint 31, the rear end portion of the hammer 33 is spline-fitted. An air vent hole 35 is appropriately formed in the middle of the hammer 33.
The hammer 33 is supported by a cam shaft 34 disposed on an extension line of the rotor shaft 18 so as to be rotatable and slidable in the axial direction. As shown in FIG. 7, a hemispherical concave groove 34b is formed on the front surface of the flange portion 34a of the cam shaft 34 over the entire circumference, leaving a protrusion 34c in a part of the circumferential direction. A ball 32 is rotatably held in the concave groove 34b, and a cam protrusion 33c is formed on the inner peripheral end surface 33b of the rear end of the hammer 33 facing the ball 32.

As shown in FIG. 4, an anvil 36 is arranged on the front side of the hammer 33. The anvil 36 is rotatably supported by the hammer case 3 via a bearing sleeve 37. The front end of the cam shaft 34 is spline-fitted to the rear end of the anvil 36.
A plurality of hammer projections 33a projecting forward in the axial direction are formed on the front surface of the hammer 33 at equal positions in the circumferential direction. Correspondingly, the rear end surface of the anvil 36 projects rearward in the axial direction. A plurality of blade portions 36a are formed. These hammer protrusions 33a and blade portions 36a have the same repetitive impact rotation torque transmission characteristics (for example, symmetrical shapes in the left-right rotation direction) with respect to the rotation of the hammer 33 in either the right rotation or the left rotation. It is said that.

A return spring 38 is interposed between the front surface of the hammer 33 and the rear surface of the anvil 36 by using the cam shaft 34 as a guide, and the hammer 33 is always pressed in a direction away from the anvil 36 in the rearward direction. ing.
At the tip of the anvil 36, an attachment portion 36b to which a tool such as a socket wrench is detachably attached is formed.
With the above structure, the hammer 33 is rotated by the rotation of the spline joint 31 that is spline-fitted with the rotor shaft 18 of the air motor 17, and the cam protrusion 33 c in FIG. 7 rotates while pushing the ball 32 in the circumferential direction. As a result, the hammer 33 is pushed forward in the axial direction against the return spring 38, and the hammer projection 33a strikes the blade portion 36a of the anvil 36 so as to rotate in the rotational direction. A hammer mechanism 39 that transmits the striking torque is configured. When the hammer 33 makes one rotation during the rotation of the hammer 33, the cam 32 rides on the protrusion 34c of the camshaft 34 only once to push the hammer 33 forward in the axial direction, and when the ball 32 gets over the protrusion 34c. The hammer 33 is immediately pushed back in the axial direction by the return spring 38. The shape of the cam protrusion 33c and the protrusion 34c of the cam shaft 34 is a shape that imparts the same axial displacement to the hammer 33 in both the right rotation and the left rotation of the hammer 33 (for example, a symmetrical shape in the left-right rotation direction). ).

As shown in FIG. 4, the inside of the control case 4 is partitioned into an exhaust chamber 40, an air supply receiving chamber 41, and an air supply passage chamber 42.
The exhaust chamber 40 has a front surface communicating with the exhaust passage 30 and a rear surface communicating with the air discharge port 16. A silencer 43 is rotatably attached to the air discharge port 16 so that the exhaust direction can be freely set. It is configured so that it can be changed. Although this silencer 43 has illustrated the shape which formed the several slit hole 43a in the outer peripheral surface of a cylindrical cap-shaped case, it is not limited to this. For example, the sound deadening material may be filled inside, and a maze-like sound deadening path may be formed. Further, a discharge hose (not shown) may be connected in place of the silencer 43, and the exhaust may be guided to a suitable place and discharged.

The rear side of the air supply receiving chamber 41 communicates with the air supply hose connection port 15, and this chamber 41 is located on the inlet side of the start valve chamber 44 formed inside the lower end side of the grip 10 of the main handle 7. The first leg 45 in the lower leg portion 9 communicates with the first leg 45.
The air supply passage chamber 42 communicates with the outlet side of the start valve chamber 44 via a second passage 46 in the lower leg portion 9 of the main handle 7.
The first passage 45 and the second passage 46 are defined by a partition wall 47 in the lower leg portion 9 of the main handle 7 (see FIGS. 4 and 6).

In the inlet side chamber (lower chamber) of the start valve chamber 44, a start valve 48 made of a ball-shaped valve body is pressed against the valve seat 50 by a valve spring 49, so that the air supply passage is always closed. It is arranged in a state of being urged by.
In the outlet side chamber (upper chamber) of the start valve chamber 44, the start valve 48 is placed against the valve spring 49 by the start lever 13 attached to the upper end portion side of the grip portion 10 of the main handle 7. A throttle pin 51 is provided for separating from the throttle pin 51.
In addition, a left / right switching valve 52 is installed in the air supply passage chamber 42. The left / right switching valve 52 includes a cylindrical body 53 and a columnar valve body 54 that is rotatably accommodated in the cylindrical body 53. As shown in FIG. 6, four window holes 55, 56, 57, and 58 are formed in the cylindrical body 53 so as to penetrate in the radial direction at intervals of 90 ° in the circumferential direction. Is communicated with the outlet side chamber of the start valve chamber 44 through the second passage 46, and the second window hole 56 and the third window hole at positions rotated 90 ° to the left and right with respect to the first window hole 55. 57 communicates with the left and right air supply passages 59, 60 communicating with the air introduction passages 28, 29. There is an exhaust chamber 61 formed at this position, and the exhaust chamber 61 communicates with the exhaust chamber 40.

  A left / right switching lever 12 is coupled to the valve body 54, and the lever 12 is configured to be able to be rotated in a range of 45 ° from the neutral position to the left and right from the neutral position. In the neutral position, the valve body 54 closes the first window hole 55 and the fourth window hole 58, and blocks the second window hole 56 and the third window hole 57 from the neutral position. When it is rotated 45 ° to the right, the first and second window holes 55 and 56 are communicated, and the third and fourth window holes 57 and 58 are simultaneously communicated, and 45 ° to the left from the neutral position. When moved, the communication grooves 54a and 54b are formed symmetrically so that the first and third window holes 55 and 57 communicate with each other and the second and fourth window holes 56 and 58 communicate with each other at the same time.

The left / right switching valve 52 can be stopped at an arbitrary angle on the way within a range of 45 ° from the neutral position to the left and right, and when stopped in the way, a window formed by the closing wall portion 54c of the valve body 54 is provided. The opening degree of the hole changes in proportion to the angle, and the supply amount of the compressed air can be adjusted.
The embodiment of the air impact wrench of the present invention has the above configuration, and the operation will be described next. A hose connection fitting 62 is attached to the air supply hose connection port 15 on the rear end surface of the main body 1, and an air hose (not shown) connected to a compressed air supply source such as a compressor is connected to the fitting 62. Keep it. When the left / right switching lever 12 is switched to the right side and the start lever 13 is operated in this state, the start valve 48 is separated from the valve seat 50 by the throttle pin 51 to open the air passage. When the operation of the start lever 13 is adjusted, the opening degree of the start valve 48 can be adjusted.

  When the start valve 48 is opened, the compressed air enters the air supply receiving chamber 41 in the control case 4 from the air supply hose connection port 15 provided on the rear end surface of the main body 1 and is formed in the lower leg portion 9 of the main handle 7. The first passage 45 passes through the inlet side chamber of the start valve chamber 44 formed in the lower portion of the grip portion 10 of the main handle 7, and further passes through the hole in the valve seat 50 and the valve gap of the start valve 48. It enters the outlet side chamber of the start valve chamber 44, enters the air supply passage chamber 42 formed in the control case 4 from here through the second passage 46 formed in the lower leg portion 9 of the main handle 7, and this air supply passage From the first window hole 55 of the cylindrical body 53 of the left / right switching valve 52 installed in the chamber 42, through the communication groove 54 a and the second window hole 56 of the valve body 54, and from the right air supply passage 59 in the control case 4. Formed on the rear end wall 2a of the motor case 2. It was then flowed through the right air introduction passage 28 from the clockwise-rotating air inlet 25 of the cylinder 19 of the air motor 17 to the eccentric cylindrical space 22 between the air motor 17 and the rotor 23 rotated to the right rotor 23.

  Exhaust air in the air motor 17 enters the exhaust chamber 40 of the control case 4 from the exhaust port 27 of the cylinder case 19 through the exhaust passage 30 of the rear end wall portion 2a of the motor case 2 and the left rotation air inlet port of the cylinder 19. 26 through the left air introduction passage 29 in the rear end wall portion 2a of the motor case 2 and the valve body 54 from the left air supply passage 60 in the control case 4 through the third window hole 57 of the cylindrical body 53 of the left / right switching valve 52. There are some which enter the exhaust chamber 61 through the communication groove 54b and the fourth window hole 58, and enter the exhaust chamber 40 from the exhaust chamber 61, both of which are provided on the rear end surface of the main body 1 through the exhaust chamber 40. The air is discharged from the plurality of slit holes 43a from the air discharge port 16 through the silencer 43.

  By supplying the compressed air to the air motor 17 of the main body 1 as described above, the rotor 23 of the air motor 17 rotates to the right. When the rotor 23 rotates to the right, the spline joint 31 that is spline-fitted with the rotor shaft 18 also rotates to the right, and the hammer 33 that is spline-fitted with this also integrally rotates to the right. By the right rotation of the hammer 33, the ball 32 rides on the protrusion 34c while rolling in the hemispherical concave groove 34b of the cam shaft 34, pushes the hammer 33 forward in the axial direction, and the blade protrusion 36a of the anvil 36 by the hammer protrusion 33a. Is repeatedly struck in the clockwise direction, and the anvil 36 is rotated clockwise while repeatedly struck in the clockwise direction. As a result, if a right-hand screw type bolt / nut is tightened with a tool (not shown) attached to the attachment portion 36b at the tip of the anvil 36, a left-hand screw type bolt / nut will be tightened. , Will do the loosening.

  The above operation is a case where the left / right switching lever 12 is switched to the right side. However, when the left / right switching lever 12 is switched to the left side, the compressed air supply path is the first between the cylindrical body 53 and the valve body 54 of the left / right switching valve 52. The window hole 55 and the third window hole 57 communicate with each other, the second window hole 56 and the fourth window hole 58 communicate with each other, and the eccentric cylindrical space 22 between the cylinder 19 and the rotor 23 of the air motor 17. Compressed air is introduced into the left rotation air introduction port 26 to rotate the rotor 23 counterclockwise, and the shaft of the hammer 33 including the spline joint 31, the hammer 33, the ball 32 on the cam shaft 34, and the cam projection 33c. The anvil 36 rotates counterclockwise through the directional displacement imparting mechanism while repeatedly striking in the direction of rotation (counterclockwise rotation) opposite to that described above. As a result, the right-screw type bolts and nuts are loosened, and the left-screw type bolts and nuts are tightened.

Further, when the left / right switching lever 12 is switched to the left / right, it can be set to an arbitrary angle within a range of 0 to 45 °, and the opening of the air passage is changed in proportion to this angle, and the flow rate of the compressed air is changed. Can be adjusted.
According to the configuration of the above embodiment, the air hose for supplying air is not obstructed by the grip portion 10 of the main handle 7 even though the main handle 7 is provided on the rear end surface of the main body 1. From the rear end face, it can be led straight back along the central axis S of the main body 1. This prevents the air supply hose from being bent excessively, and can also avoid collisions with surrounding members and scratches. Therefore, tighten and loosen bolts and nuts in narrow spaces. In this case, the air hose for supplying air does not hinder the work.

Further, since the main handle 7 and the auxiliary handle 11 are attached offset to the same side with respect to the central axis S of the main body 1, the operator holds the main handle 7 on the rear end surface of the main body 1 with a dominant hand. Then, with this position as the starting point, the front auxiliary handle 11 is grasped with the other hand, and the tool at the tip of the anvil 36 can be operated easily and stably toward the object in front of the operator. Thus, the main body 1 can be easily held and directed toward the object, and operability can be improved and fatigue can be reduced.
Further, since the air discharge port 16 is formed on the rear end surface of the main body 1 so as not to overlap the grip portion 10 of the main handle 7, the discharge hose is also used when the silencer 43 is connected. Even when connected to the main handle 7, it does not interfere with the grip 10 of the main handle 7, does not protrude from the outer periphery of the main body 1, and interference with peripheral members can be avoided.

  The configuration and operation of the embodiment of the present invention are as described above. However, the present invention is not limited to this embodiment, and various modifications may be made within the meaning and scope described in the claims. For example, the air motor 17 and the hammer mechanism 39 may employ other configurations. Moreover, although the case where the silencer 43 is provided in the air discharge port 16 is illustrated, instead of this, a discharge hose may be connected and exhausted to a place away from the tightening work place. The structure of the silencer 43 may be another structure. Furthermore, although the case where the starting lever 13 is provided in the outer upper part (rear side upper part) of the grip 10 of the main handle 7 is illustrated, it may be provided in the inner upper part (front side upper part).

It is a side view of the air impact wrench concerning the embodiment of the present invention. It is the bottom view seen from the bottom of FIG. It is the end elevation seen from the right side of FIG. It is a vertical side view of FIG. It is a longitudinal cross-sectional view of the air motor part of FIG. It is a cross-sectional view of the left / right switching valve portion of FIG. It is a schematic perspective view which shows the relationship between the cam protrusion part of the hammer in FIG. 4, and the ball | bowl of a cam shaft.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main body 2 Motor case 3 Hammer case 4 Control case 7 Main handle 11 Auxiliary handle 12 Left / right switching lever 13 Start lever 15 Air supply hose connection port 16 Air discharge port 17 Air motor 18 Rotor shaft 19 Cylinder 23 Rotor 24 Rotor blade 31 Spline joint 32 Ball 33 Hammer 34 Cam shaft 36 Anvil 39 Hammer mechanism 40 Exhaust chamber 41 Air supply receiving chamber 42 Air supply passage chamber 43 Silencer 44 Start valve chamber 48 Start valve 52 Right / left switching valve 53 Cylindrical body 54 Valve body 55-58 Window Hole

Claims (3)

An air motor (17) and a hammer mechanism (39) are provided in the main body (1), and compressed air is supplied to the air motor (17) by switching between a normal rotation direction and a reverse rotation direction via a left / right switching valve (52). Then, a rotational torque is generated, the rotational torque is transmitted to the hammer mechanism (39), and a hammering torque in the rotational direction is transmitted from the hammer mechanism (39) to the anvil (36). In an air impact wrench that tightens or loosens bolts and nuts with a tool attached to the tip,
On the rear end surface of the main body (1), there are upper and lower leg portions (8) and (9) that protrude obliquely rearward with respect to the central axis (S) of the main body (1), and the upper and lower leg portions (8 ) (9) is formed in series with a main handle (7) consisting of a gripping part (10) formed between the protruding ends, and the gripping part (10) is in relation to the central axis (S) of the main body (1). The air hose connection port (15) for supplying air to the air motor (17) is attached to the gripping portion (10) of the main handle (7) on the rear end surface of the main body (1). Air impact wrench characterized by being formed so as not to overlap.   The air exhaust port (16) is formed in the rear end surface of the main body (1) so as not to overlap the grip portion (10) of the main handle (7). Air impact wrench.   The air impact wrench according to claim 2, wherein a silencer (43) or a discharge hose can be connected to the air discharge port (16).

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