JP2002210672A - Oil unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the torque in generating oil pulation. SOLUTION: A first pin 33 and a second pin 34 are respectively projected from front and rear end faces of blades 28, 28 mounted on a large part 25 of a spindle 22 in a liner 7, and elliptic first and second cam grooves 31, 32 are respectively formed on opposite faces of a bottom cap 4 and a top cap 17 for guiding the first and second pins 33, 34 in accompany with the rotation of a case 2, and preventing tip faces of the blades 28, 28 from slidably abutted on second seal faces 16, 16 corresponding to ribs 27.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil unit which is used for an electric tool such as a torque wrench and outputs transmitted torque as instantaneous torque by hydraulic pressure.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional oil unit 50. The oil unit 50 has a liner 5 connected to an output shaft or the like of a motor for torque transmission in a cylindrical case 51.
2 are integrally accommodated, and the front and rear in the axial direction are closed by a cap (not shown) as a closing portion to form an oil chamber 53, and a spindle 54 is supported in the oil chamber 53 by the cap. The spindle 54 has a pair of blades 5
5 and 55 are freely inserted and retracted in the radial direction of the spindle 54 and urged in the protruding direction by the coil spring 62, and a pair of ribs 56 and 56 project from the blades 55 and 55 with a phase difference of 90 °. ing. On the other hand, oblong guide holes 57, 57 with which the tip surfaces of the blades 55, 55 are in sliding contact with each other in the axial direction of the liner 52, respectively, are bored. The first connecting portions 58, which are the first sealing surfaces 59, 59 that match the inner peripheral shape of
58, and second connecting portions 60, 60 having second sealing surfaces 61, 61, the inner surfaces of which also match the inner peripheral shape of the guide hole 57.
Are formed in the axial direction of the liner 52 with a phase difference of 90 ° from each other. Therefore, as shown in FIG.
2, the blades 55, 55 which rotate relatively along the inner peripheral surfaces of the guide holes 57, 57 on the first sealing surfaces 59, 59 and the ribs 56, 56 on the second sealing surface 6 are rotated.
When the pressure reaches 1 and 61 respectively, the oil chamber 53 is partitioned into four, and high-pressure chambers and low-pressure chambers are generated alternately, and an impact torque (oil pulse) is generated on the spindle 54 by this pressure difference. As such an oil unit, one disclosed in Japanese Utility Model Publication No. Hei 6-27341 is known.

[0003]

The above oil unit 5
0, the blade 55, 55 and the ribs 56, 56 are separated from the first and second sealing surfaces 59, 61 by the rotation of the liner 52 after the generation of the oil pulse, so that the oil chamber 5
3, the oil pulse is not generated and only the liner 52 rotates (FIG. 4).
(B)). Therefore, the blades 55, 55
The blade 5 slides along the inner peripheral surface of the guide hole 57 with the rotation of the blade 5 and gradually approaches the second seal surfaces 61, 61.
5 and 55 are gradually pushed into the spindle 54, and the urging force of the coil spring 62 on the blades 55 and 55 is increased (FIG. 4C), and the blades 55 and 55 are brought into contact with the second sealing surfaces 61 and 61. It becomes maximum at the position of FIG. Therefore, the blade 5 is inserted into the inner peripheral surface of the guide hole 57.
Rotational resistance is generated on the spindle 54 by the pressing force of 5,55. Further, since the guide hole 57 is formed by a combination of three circles, the second hole which is an intersection of the circles is formed.
Both sides of the sealing surfaces 61, 61 project slightly, and the blade 55, 55 crosses the intersection P, so that rotation resistance is also generated.

FIG. 5 is a graph showing the torque generated in the oil unit 50, where a, a,... Are the torques generated by the generation of the original oil pulse. It can be seen that small torques b, b. As described above, the unnecessary torque generated due to the rotational resistance on the spindle 54 reduces the torque obtained when the original oil pulse is generated.

Accordingly, an object of the present invention is to provide an oil unit capable of effectively reducing the rotational resistance of a spindle other than when an oil pulse is generated and increasing the torque when an oil pulse is generated. It is intended.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, pins are respectively provided on end faces of a spindle in a front and rear direction of a spindle in the axial direction.
A cam groove is provided on each of the opposing surfaces of the closing portion to guide the pin with the rotation of the case and to prevent the leading end surface of the blade from sliding on the sealing surface corresponding to the rib. It is. According to a second aspect of the present invention, in addition to the object of the first aspect, a blade often used in an oil unit and a sealing surface corresponding to the blade are provided two by two. In order to more effectively increase the torque at the time of generation of the pulse, the length of the pin is changed for each blade, and the cam groove is formed as an oval deep first cam groove for guiding the longer first pin. A shallow second cam groove having an oval shape for guiding the shorter second pin, and the first cam groove having the second longitudinal direction having one longitudinal end shared with the second cam groove, having a second dimension. The blade is made shorter than the cam groove so that the first pin is guided by the first cam groove so that the blade cannot slide on one of the sealing surfaces. The oval shape in the present invention includes an elliptical shape in addition to the oval shape itself.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. 1A is a sectional view of the oil unit 1 in the axial direction, FIG. 1B is a sectional view taken along line AA, FIG. 1C is a sectional view taken along line BB, and FIG. It is a C line sectional view. In the oil unit 1, reference numeral 2 denotes a cylindrical case, and a disc-shaped bottom cap 4 is loosely inserted into the case 2 as a closing part from the rear (the left side in FIG. 2A is described as the front). 2 Abuts the stopper 3 at the front end to close the front of the case 2. 5 is a stopper 3
And a spring pin 6 for inserting the bottom cap 4 with the case 2 in the rotation direction through the cutout of the stopper portion 3. The working oil can be supplied from here by the bolt.

A liner 7 is rotatably inserted into the case 2 behind the bottom cap 4 so as to be rotatable.
8 and are integrally connected to the bottom cap 4. The liner 7 includes a pair of front and rear plates 9 and 1 each having an oval guide hole 11 formed by combining three circles.
0 is connected to a pair of first connecting portions 12 and 12 disposed on both sides in the longitudinal direction of the guide hole 11 and second connecting portions 13 and 13 disposed on both sides in the lateral direction. On the opposing surfaces of the first connecting portions 12, 12 are formed first sealing surfaces 14, 14 which match the inner peripheral surface of the guide hole 11.
Protrusions 15, 15 protrude from the centers of the protrusions 15, 15, and second sealing surfaces 16, 16 that match the inner peripheral surface of the guide hole 11 are formed on opposing surfaces of the protrusions 15, 15. . Further, behind the liner 7, a disc-shaped top cap 17 is provided as a rear closed portion so as to be rotatable and movable in the axial direction.
And is integrally connected to the liner 7 in the rotational direction by a plurality of pins 18. A top nut 21 is screwed into the case 2 behind the top cap 17 via a disc spring 20.
The top cap 17 can be fixed by the urging force of the disc spring 20 due to the screwing of. 19 is the top cap 1
7 is a cylindrical connecting portion that protrudes rearward from the front end 7 and that opens a hexagonal hole at the rear end.

Reference numeral 22 denotes a spindle, and a front end output portion 23 penetrates the bottom cap 4 and projects forward of the case 2.
The rear cylindrical portion 24 is loosely inserted into a bottomed hole on the front surface of the top cap 17 and is rotatably supported on each. In the center of the spindle 22, the guide holes 11, 11 of the liner 7 are provided.
A large-diameter portion 25 is formed in the liner 7 so as to conform to the middle circle of the liner. Groove 2
A pair of ribs 2 having a phase difference of 90 ° in the circumferential direction with 6, 26
7 and 27 are formed in the axial direction, respectively, and the storage grooves 26 and 26 are formed.
The blades 28, 2 having the same axial length as the large diameter portion 25
8 are stored so as to be able to swing slightly in the circumferential direction. The blades 28, 28 are urged in the direction away from each other by two coil springs 29, 29 interposed therebetween, so that the front and rear end surfaces contact the inner peripheral surfaces of the guide holes 11, 11 of the liner 7. It is to let. Therefore, at the rotation position of the spindle shown in FIG. 1C, the blades 28, 28 contact the first sealing surfaces 14, 14 of the liner 7, and the ribs 27,
27 comes into contact with the second sealing surfaces 16, 16, so that the oil chamber 30 formed in the liner 7 can be divided into four.

On the other hand, on the opposing surfaces of the bottom cap 4 and the top cap 17, first and second elliptical cam grooves 31 and 32 whose longitudinal directions coincide with the guide holes 11 of the liner 7 are formed. It is formed. The first cam groove 31 is shown in FIG.
As shown in FIG. 3, the second cam groove 32 is formed near the end face of the large-diameter portion 25 of the spindle 22 so as to substantially include the output portion 23 and eccentric from the axis of the spindle 22.
Shares an ellipse with the first cam groove 31 in the eccentric direction,
The side opposite to the eccentric direction of the first cam groove 31 is a long oval reaching near the end face of the large diameter portion 25 and is formed shallower than the first cam groove 31.

On the front and rear end surfaces of one of the blades 28, first pins 33, 33, which are loosely inserted into the first cam grooves 31 and are longer than the depth of the second cam grooves 32, respectively, are protruded. On the front and rear end surfaces, second pins 34, 34, which are loosely inserted into the second cam grooves 32 and are slightly shorter than the depth of the second cam grooves 32, respectively, are protruded. Therefore, the blades 28, 28
The protruding position is regulated by interference between the first pins 33, 33 and the inner peripheral surface of the first cam groove 31, and interference between the second pins 34, 34 and the inner peripheral surface of the second cam groove 32. However, the blades 28, 28 are located at positions parallel to the longitudinal direction of the first and second cam grooves 31, 32, and the blades 28, 28 contact the inner peripheral surfaces of the guide holes 11, 11. At the rotational position (positions of FIGS. 1C and 1D), the first and second pins 33 and 34 are separated from the inner peripheral surfaces of the first and second cam grooves 31 and 32, respectively, and the blades 28 and 28 First and second cam grooves 3
When the first and second pins 33 and 34 are at positions parallel to the short direction of the first and second short positions (positions rotated by 90 degrees from FIGS. 1C and 1D), the first and second pins 33 and 34 are the first and second cam grooves, respectively. The protrusions of the blades 28 are restricted by contacting the inner peripheral surfaces of the blades 31 and 32. At this time, the tip surfaces of the blades 28, 28 are buried deeper than the end surface of the large diameter portion 25, and are not in contact with the guide holes 11, 11.

The oil unit 1 configured as described above
As shown in FIG. 2, the tip of the carrier 39 of the planetary gear reduction mechanism 38, which is housed in the housing 36 of the impulse driver 35, and is rotationally transmitted from the motor 37 to the connecting portion 19 of the top cap 17. On the other hand, the output portion 23 of the spindle 22 is provided with a chuck 40 protruding forward from the housing 36 while being connected. Therefore, the motor 3
When the carrier 39 and the top cap 17 rotate integrally with the rotation of the case 7, the case 2 and the liner 7 are connected as shown in FIG.
The blade 2 rotates clockwise in the direction of the arrow and rotates relatively.
8 and 28 are inclined in the rotation direction of the case 2 with the guide holes 1
Sliding on the inner surfaces of 1,11. And the blades 28, 2
8 reaches the position of the first sealing surfaces 14,
When the oil chamber 30 is divided into four parts and sealed together with 7, 27, a high-pressure chamber and a low-pressure chamber are generated alternately in the oil chamber 30,
The output torque to the spindle 22 is instantaneously increased via the blades 28 and 28 by the pressure difference to rotate the spindle 22 (oil pulse generation).

Thereafter, as the case 2 continues to rotate, the first and second cam grooves 31, 32 of the bottom cap 4 and the top cap 17 also rotate, and as shown in FIG. Since the first pin 33 slides along the inner peripheral surface of the first cam groove 31 and the second pin 34 of the other blade 28 slides along the inner peripheral surface of the second cam groove 32, the blade 2
8 and 28 are gradually drawn into the large-diameter portion 25 by the inner peripheral surfaces of the first and second cam grooves 31 and 32 whose distance from the axis of the spindle 22 gradually decreases with rotation, and the liner 7 is moved. At the position shown in FIG. 3C immediately before the rotation of approximately 90 °, the blades 28, 28 are separated from the inner peripheral surface of the guide hole 11, respectively.
At the position shown in FIG. 3D where the liner 7 has been rotated by approximately 90 °, the distance between the first pin 33 and the second pin 34 is the longest depending on the short dimension of the first and second cam grooves 31 and 32. Because the blades 28 and 28 are close to each other, the blades 28 and 28 are completely immersed in the large diameter portion 25, and the blades 28 and 28 are
Passes without sliding.

When the case 2 continues to rotate, the one blade 28 is gradually rotated to the large diameter portion by the short second pin 34 being guided to the inner peripheral surface of the second cam groove 32, contrary to the above operation. When the liner 7 protrudes from the position 25 and the liner 7 is rotated by 180 °, the liner 7 comes into contact with the first sealing surface 14 again as shown in FIG. 3E, but the other blade 28 has the long first pin 33 eccentric. By being guided by the inner peripheral surface of the first cam groove 31, the first cam groove 31 rotates without projecting from the large diameter portion 25,
The oil chamber 30 is not sealed away from the first seal surface 14. Therefore, no oil pulse is generated at this position, and the liner 7 is further rotated by 180 ° from this position to rotate the first and second pins 3.
An oil pulse is generated at the position shown in FIG. 3A where the third and the third abut against the inner peripheral surfaces of the first and second cam grooves 31 and 32 again.
That is, even if there are a pair of blades 28, 28, one rotation of the case 2 generates one oil pulse.

As described above, according to the above embodiment, the long first pins 33, 33 are provided on the end face of one blade 28, and the short second pins 34, 34 are provided on the end face of the other blade 28, respectively. The first and second pins 33, 34 are guided by the rotation of the case 2 to the opposing surfaces of the cap 4 and the top cap 17, and the tip surfaces of the blades 28, 28 correspond to the ribs 27, 27. The first and second cam grooves 31 and 32 for preventing sliding contact with the sealing surfaces 16 and 16 respectively provide the leading end surfaces of the blades 28 and 28 with the guide holes 1.
The inner peripheral surface of the spindle 22 is slid in contact with the large diameter portion
Rotational resistance caused by being pushed into the space 5 and rotational resistance caused by overcoming the second seal surfaces 16, 16 can be completely eliminated, and the torque at the time of generation of the original oil pulse can be increased. That is, in the graph of FIG. 5, the torques b, b.
a can be increased. Here, the cam grooves are a deep first cam groove 31 for guiding the longer first pin 33 and a shallow second cam groove 32 for guiding the shorter second pin 34, and the first cam groove The length of the groove 31 is set to the second length while the one longitudinal end is shared with the second cam groove 32.
Since the length of the blade 28 is shorter than the length of the cam groove 32 and the first pin 33 is guided by the first cam groove 31, the blade 28 cannot slide on one of the first sealing surfaces 14.
Even in the case of using the motors 8 and 28, the oil pulse generation cycle of once per rotation of the case 2 is maintained, and the torque per rotation can be more effectively increased together with the elimination of the rotation resistance. ing.

In the above embodiment, the first cam groove 31 and the second
By making the depth and length different from the cam groove 32, the sliding contact between the first and second pins 33 and 34 of each blade 28 allows
Although it is possible to generate one oil pulse per rotation,
Eliminating such a difference, a single cam groove is formed, and a pin of the same length slidingly contacting the cam groove is protruded from each blade to generate two oil pulses in one rotation. Also, the effect of increasing the torque due to the non-contact of the liner 7 with the guide holes 11, 11 can be obtained. In addition, the number of blades is not limited to two, and may be one or three. The shape of the cam groove is not limited to the above-described configuration in which the entire surface of the ellipse is recessed, and the pin may be loose. A concave strip having a width that can be inserted may be continuously formed in an oval shape. Further, an elliptical shape other than an elliptical shape can be adopted.

[0017]

According to the first aspect of the present invention, the pins are respectively provided on the front and rear end faces of the spindle in the axial direction of the blade, and the pins are provided on the opposing surfaces of the closing portion with the rotation of the case. Are provided to prevent the tip surface of the blade from sliding on the seal surface corresponding to the rib, so that the tip surface of the blade slides over the seal surface corresponding to the rib and gets over the seal surface. This can completely eliminate the occurrence of rotational resistance, and can increase the torque at the time of the original oil pulse generation. According to the second aspect of the present invention, in addition to the effect of the first aspect, in the case where two blades and two corresponding sealing surfaces are provided, the length of the pin is changed for each blade. On the other hand, the cam grooves are an oval deep first cam groove for guiding the longer first pin and an oval shallow second cam groove for guiding the shorter second pin. The length of the cam groove is made shorter than the length of the second cam groove while sharing one of the longitudinal ends with the second cam groove, and the blade is guided to the one sealing surface by the guide of the first pin by the first cam groove. By making the sliding contact impossible, the oil pulse generation cycle of once per rotation of the case is maintained, and the torque per rotation can be more effectively increased together with the elimination of the rotation resistance.

[Brief description of the drawings]

FIG. 1A is an axial sectional view of an oil unit. (B) It is a sectional view on the AA line. (C) It is BB sectional drawing. (D) It is a CC sectional view.

FIG. 2 is an explanatory diagram of an impulse driver provided with an oil unit.

FIG. 3A is an explanatory sectional view showing movement of a blade accompanying rotation of a case. (B) It is sectional explanatory drawing which shows the movement of the blade accompanying rotation of a case. (C) It is sectional drawing which shows the movement of the blade accompanying rotation of a case. (D) It is sectional explanatory drawing which shows the movement of the blade accompanying rotation of a case. (E) It is sectional explanatory drawing which shows the movement of the blade accompanying rotation of a case.

FIG. 4A is an explanatory sectional view showing the movement of a blade in a conventional oil unit. (B) It is sectional explanatory drawing which shows the movement of the blade in the conventional oil unit. (C) It is sectional explanatory drawing which shows the movement of the blade in the conventional oil unit. (D) It is sectional explanatory drawing which shows the movement of the blade in the conventional oil unit.

FIG. 5 is a graph showing an oil pulse generation state in a conventional oil unit.

[Explanation of symbols]

1. Oil unit, 2. Case, 4. Bottom cap, 7. Liner, 14. First seal face, 16.
2nd sealing surface, 17 top cap, 22 spindle, 25 large diameter section, 28 blade, 30
Oil chamber, 31 first cam groove, 32 second cam groove, 3
3. First pin, 34 second pin, 35 impulse driver.

Claims (2)

[Claims] 1. A spindle is inserted into a cylindrical case filled with hydraulic oil, and the spindle is rotatably supported by closing portions at both ends of the case. A plurality of blades and ribs that are divided into a plurality of oil chambers are provided at equal intervals, and the relative rotation of the case and the spindle causes the leading end surfaces of the blades and the ribs to slidably contact the inner surface of the case, and An oil unit that generates a pressure difference between the oil chambers at a position where a tip end surface with a rib reaches a sealing surface formed corresponding to the inner surface of the case, thereby generating an instantaneous torque to the spindle. In the blade, pins are respectively protruded on the front and rear end surfaces of the spindle in the axial direction, while the pins are provided on opposing surfaces of the closing portion with rotation of the case. And the inner,
An oil unit having a cam groove for preventing a leading end surface of the blade from slidingly contacting a sealing surface corresponding to the rib. 2. In the case where two blades and two corresponding sealing surfaces are provided, the length of the pin is changed for each blade, and the cam groove guides the longer first pin. An elliptical deep first cam groove and an elliptical shallow second cam groove for guiding a shorter second pin, and the first cam groove is formed such that one longitudinal end is the second
The length of the longitudinal direction is shorter than that of the second cam groove while being shared with the cam groove, so that the first pin is guided by the first cam groove so that the blade cannot slide on one seal surface. 2. The oil unit according to 1.