JPH08323640A - Oil seal structure for hammering part of hydraulic torque wrench - Google Patents

Abstract

PURPOSE: To increase the sealing property of a hydraulic torque wrench at its hammering part. CONSTITUTION: A space which is open to a hydraulic chamber side from a ring recessed part 1 formed for storing an O-ring between the bottom cap 5 of a hydraulic torque wrench at the hammering part and a spindle 3 is positioned in the middle position of the recessed part 7 in its thickness direction. By this, a hydraulic pressure is applied to the middle part of the cross-section of an O-ring 1. Thus, because the hydraulic pressure is applied to the middle part of the cross-section of the O-ring, when the O-ring 1 is deformed, its sealing property is more increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liner cap (one or both of a bottom cap and a top cap. The term "cap" has the same meaning below) of a liner of a striking portion of a hydraulic torque wrench. O between the spindle
The present invention relates to an oil seal structure including a ring.

[0002]

2. Description of the Related Art Conventionally, as an oil seal structure of a hitting portion of such a hydraulic torque wrench, Japanese Patent Laid-Open No. 6-226 is known.
There are a type as shown in Japanese Patent No. 652 and a type as shown in Japanese Utility Model Publication No. 1-29012. As shown in FIG. 6A, the former accommodates an O-ring 105 in a ring groove 103 provided on the spindle 101 side and has a bottom cap 107 having an inner peripheral surface flush with the outer peripheral surface of the spindle 101. Was attached. In the latter, as shown in FIG. 6 (B), the step portion 113 is provided on the spindle 111 side, and the bottom cap 1
15 terminals are provided with a hook-shaped section 1 corresponding to this step 113.
17 and the O-ring 119 between these 113 and 117.
Was attached.

[0003]

Therefore, as shown in FIG.
As shown in (C) and (D), when the O-rings 105 and 119 are deformed by the oil leaked from the hydraulic chamber side, there is a problem in that a gap is likely to be formed on the seal surface, causing oil leakage. In particular, in a hydraulic torque wrench that generates an impact torque, hydraulic oil may leak out in a short time due to such a defective seal.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to improve the sealing performance at the striking portion of a hydraulic torque wrench.

[0005]

In the oil seal structure of the striking portion of the hydraulic torque wrench according to the present invention, an O-ring is interposed between the cap and the spindle provided on the striking portion of the hydraulic torque wrench. In the resulting oil seal structure, the hydraulic pressure from the hydraulic chamber is applied to the middle of the cross section of the O-ring.

That is, as illustrated in FIG. 1 (A), since the hydraulic pressure is applied in the middle of the cross section of the O-ring 1, when the O-ring 1 is deformed, the sealability is rather improved. Figure 6
It can be clearly understood from the comparison with (C) and (D) that the present invention surely improves the sealing property.

Such an oil seal structure is, for example,
By locating a gap that opens from the ring-shaped recess formed for accommodating the O-ring between the cap and the spindle toward the hydraulic chamber, in the middle of the thickness direction of the recess, the middle of the cross section of the O-ring. It can be configured so that hydraulic pressure is applied to.

In particular, in constructing the ring-shaped recess, a stepped portion is formed on the spindle side so as to have a larger diameter from the middle when viewed in the opposite direction from one end, and a fitting hole on the cap side. Comprises a fine hole portion and a thick hole portion so that the step portion can be fitted across the fine hole portion, and the end of the thick hole portion matches the step portion between the fine hole portion and the thick hole portion. Therefore, it is preferable to form a peripheral groove having a diameter larger than that of the thick hole portion. The above-mentioned FIG. 1 (A) illustrates this, and the spindle 3
Side is provided with a step portion 3a, and the bottom cap 5 side is provided with a groove portion 5a.
And a recess 7 is formed by both.

As shown in FIG. 1B, the combination grooves 5b and 3b are formed on both the bottom cap 5 and the spindle 3.
May be provided, and these may be combined to form the recess 7 for accommodating the O-ring. However,
It is better to form the step 3a on the spindle 3 and to provide the groove 5a on the bottom cap 5 as shown in (A).
There is an advantage that the assembly is simple. This is because, for example, the O-ring 1 may be first fitted into the groove 5a of the bottom cap 5, and then the O-ring 1 may be mounted together with the bottom cap 5 from the tip end side of the spindle 3. Further, since such an assembling method is possible, there is an advantage that the O-ring 1 is less likely to receive an excessive force and is less likely to be damaged when the bottom cap 5 and the spindle 3 are fitted together.

In the oil seal structure of the striking portion of this hydraulic torque wrench, as illustrated in FIG. 1C, for example, a backup ring 9 is provided in the recess so as to back up the O ring 1 from the spindle tip side. If it is also attached, the sealing property will be further improved. This is because the backup ring 9 increases the axial adhesion between the O-ring 1 and the recess 7. It should be noted that the backup ring 9 itself may also be made to exhibit a sealing property.

Although FIG. 1 exemplifies the seal structure between the bottom cap and the spindle, the seal structure between the top cap and the spindle can be similarly configured. It would be more desirable to employ the oil seal structure of the present invention both between the bottom cap and the spindle and between the top cap and the spindle, but only one would have the oil seal structure according to the present invention and the other would be conventional. An oil seal structure or another oil seal structure may be used. This is because the sealability is improved even if only one side is used.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 2, a hydraulic torque wrench 10 according to an embodiment has a spindle 13 rotatably assembled to the center of a liner 11 in which hydraulic oil is sealed.
A blade (not shown) and a liner 1, which are arranged so as to be able to project and retract freely in 3
A high pressure chamber and a low pressure chamber are formed in the liner 11 in accordance with the contact state with the inner wall of No. 1 to generate shocking torque in the spindle 13.

As shown in FIG. 3, the spindle 13 is provided with a step portion 13a around the bottom cap 15 to be mounted, the tip of which is a small diameter portion 13b, and the hydraulic chamber side is a large diameter portion 13c. . Further, the portion accommodated in the hydraulic chamber has a modified cross section, and blade mounting grooves 13d, 13e, 13f are provided on the left and right and below. In addition,
In FIG. 3B, the cross-sectional shape of the liner 11 is shown by the alternate long and short dash line, and three blades B1 to B3 are also shown.

On the other hand, as shown in FIG. 4, the bottom cap 15 has a large diameter portion 13c and a small diameter portion 13b of the spindle 13.
1 has a small inner diameter so as to come into surface contact with each of the
5a and a large hole portion 15b having a large inner diameter are formed. Then, in the middle, the ring groove 15c is engraved so as to have a larger inner diameter.

An end surface 15d of the ring groove 15c on the hydraulic chamber side.
When the bottom cap 15 is mounted on the spindle 13, it matches the stepped portion 13a. The stepped portion 13a and the ring groove 15c form a ring-shaped recess 19 for housing the O-ring 17.

When assembling, the O-ring 17 is used.
Is first fitted into the ring groove 15c of the bottom cap 15, and then, together with the O-ring 17, the spindle 1
The bottom cap 15 is attached from the tip side of 3. With such an assembly method, when the bottom cap 15 and the spindle 13 are fitted to each other, the O-ring 17 is unlikely to receive an excessive force and is not easily damaged.

With the above-mentioned structure, the oil seal structure portion of this embodiment can exhibit a high sealing property by the action as already described in FIG. 1 (A). Note that in FIG. 2, the symbol M indicates a motor. When the top cap 21 is rotated by this motor M,
The liner 11 also rotates, and the spindle 13 is rotated while generating impact torque according to the state of contact with the blade attached to the spindle 13.

Next, a second embodiment will be described. In the second embodiment, as shown in FIG. 5, a Teflon backup ring 23 is also attached to the spindle tip side of the ring-shaped recess 19. Other configurations are the same as in the first embodiment. The backup ring 23 is configured such that its inner diameter is matched with the small diameter portion 13b of the spindle 13 and its outer diameter is matched with the inner diameter of the ring groove 15c of the bottom cap 15 so that the backup ring 23 itself also exhibits sealing performance. There is.

According to the second embodiment, as already described with reference to FIG. 1C, the axial contact between the O-ring 17 and the recess 19 is increased to deform the O-ring 17 by hydraulic pressure. It's getting harder. Further, since the backup ring 23 itself has a sealing property, it is possible to exhibit a higher sealing performance than that of the first embodiment.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments.
The above-described O-ring seal structure may be applied to the top cap side seal structure, and can be modified into various forms without departing from the scope of the present invention.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an essential part exemplifying an operation of the present invention in an easily understandable manner.

FIG. 2 is a sectional view of an essential part of the hydraulic torque wrench of the first embodiment.

FIG. 3 shows a spindle used in the first embodiment,
(A) is a front view, (B) is a left side view, and (C) is a bottom view.

FIG. 4 shows a bottom cap used in the first embodiment,
(A) is a sectional view as seen from the front, and (B) is a right side view.

FIG. 5 is a sectional view of a main part of a hydraulic torque wrench according to a second embodiment.

FIG. 6 is an explanatory view showing a cross section of a conventional oil seal structure and its action.

[Explanation of symbols]

1 ... O-ring, 3 ... Spindle, 3a ... Step, 3b ... Combination groove, 5 ... Bottom cap, 5a ... Groove part, 5b ... Combination groove, 7 ...・
Recess, 9 ... backup ring, 10 ... hydraulic torque wrench, 11 ... liner, 13 ... spindle, 13a ... step, 15 ... bottom cap,
15c ... Ring groove, 17 ... O-ring, 19 ...
・ Ring-shaped recess, 21 ・ ・ ・ Top cap, 23 ・ ・
-Backup ring, M ... Motor.

Claims (4)

[Claims] 1. In an oil seal structure in which an O-ring is interposed between a cap and a spindle provided in a striking portion of a hydraulic torque wrench, a hydraulic pressure from a hydraulic chamber is applied in the middle of a cross section of the O-ring. The oil seal structure of the striking part of the hydraulic torque wrench is characterized by 2. The oil seal structure for the striking portion of the hydraulic torque wrench according to claim 1, wherein a ring-shaped recess formed for accommodating the O-ring between the cap and the spindle opens toward the hydraulic chamber. The oil seal structure of the striking portion of the hydraulic torque wrench is characterized in that the hydraulic pressure is applied to the middle of the cross section of the O-ring by locating the gap in the middle of the recess in the thickness direction. 3. The oil seal structure for the striking portion of the hydraulic torque wrench according to claim 2, wherein when forming the ring-shaped recess, the spindle side is thicker from the middle when viewed in the opposite direction from one end. The stepped portion is formed to have a diameter, and the fitting hole on the cap side is composed of a fine hole portion and a thick hole portion so that the fitting hole can be fitted across the stepped portion. An oil of a striking portion of a hydraulic torque wrench, characterized in that a peripheral groove having a diameter larger than that of the thick hole portion is formed so that an end of the thick hole portion matches the step portion. Seal structure. 4. In the oil seal structure for the striking portion of the hydraulic torque wrench according to claim 2 or 3, a backup ring is installed in the recess so as to back up the O-ring from the spindle tip side. The oil seal structure of the striking part of the characteristic hydraulic torque wrench.