JPH0225935Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to cylinder devices operated by hydraulic pressure from a master cylinder, such as clutch operating cylinders or brake wheel cylinders, and is particularly applicable to air bleed cylinders. This invention relates to a cylinder device with improved properties.

(Prior Art and its Problems) Generally, in this type of cylinder device, the cylinder body includes two holes in addition to the cylinder hole in which the piston slides. One of the holes is
This is a piping connection port for introducing hydraulic pressure from the master cylinder, and the other is a hole for air release. In order to avoid impairing the sliding movement of the piston, these holes are provided on the bottom side of the cylinder in the case of a cylinder device with one end open, and in the center of the cylinder in the case of a cylinder device with both ends open. and the opening of each hole to the cylinder hole is usually arranged separately.

By the way, among such cylinder devices, in the case of small ones, both the holes have to be arranged close to each other. This is because, in addition to the restriction that each hole must be provided on the bottom side or the center of the cylinder, the hole for air vent must be provided on the top side of the cylinder body, and there are also restrictions on piping connections. This is because there is a restriction that the holes for the pipes can be easily connected to the pipes.

Therefore, among the conventional examples, for example,
As shown in the publication No.-52427, a structure is known in which both holes share the same opening for the cylinder hole.

However, in the case of such a structure in which the openings of both holes are shared, although it is advantageous in terms of downsizing the cylinder device, there is an undeniable drawback in terms of air removal.

Methods for filling oil into the liquid chamber defined in the cylinder hole include a vacuum breathing method in which the liquid chamber is under negative pressure, a pressure feeding method in which the oil is pumped, or a pumping method in which the piston is reciprocated. will be adopted. In the conventional technology in which the openings of both the holes are shared, especially when using the pressure feeding method and the pumping method, the oil supplied into the liquid chamber entrains the air that is trying to escape, making it difficult to bleed the air. Unfortunately, there is a problem that the oil filling operation cannot be performed efficiently.

On the other hand, Japanese Utility Model Publication No. 59-4187 shows a different idea in which an opening for supplying oil and an opening for venting air are arranged concentrically. According to this idea, since both openings are in the same location but separate from each other, air removal performance can be improved compared to the case where the openings are shared.

However, in that technology, the joint member that defines both openings is made movable relative to the cylinder, and the air bleed port is opened at one position and closed at the other position. . Therefore, the joint member is inserted into the cylinder hole, which causes the cylinder device to become larger. In this regard, to be more specific, it is necessary to provide a space on the cylinder side to accommodate the inner end of the joint member and a space to avoid contact with internal parts such as the piston. As a result, the cylinder hole becomes larger and the overall size becomes larger.

(Purpose of the invention) This invention was made in consideration of the above points, and its purpose is to provide a technology that can improve air bleed performance while reducing the size of the cylinder device. .

Another object of this invention is to provide a technique that allows for less interference between the oil flow and the air flow and allows better air removal.

(Means for achieving the object) In this invention, the opening of the air bleed passage is arranged so as to surround the opening of the oil supply passage, but it is possible to reduce the size of the cylinder device and prevent air from being entrained. In order to reduce the size, the opening part of the oil supply passage is arranged at a predetermined part facing the cylinder hole, and the structure is such that each flow of air can be separated from each other.

To be more specific, a cylindrical member having an internal passage and an inner end extending toward the liquid chamber is fixed and attached to the first hole at a constant height such that the inner end is located within the first hole. , a gap is formed between the outer circumference of the inner end of the cylindrical member and the inner wall of the first hole, and the inner end of the second hole is opened in the gap,
Moreover, at least a part of the internal opening of the internal passage directly faces the cylinder hole, and further,
The inner end of the hole opens into the gap on the axial side of the cylinder hole closer to the piston.

(Function) First, regarding the miniaturization of the cylinder device,
Since the first hole and the second hole are arranged to open at the same location, the structure is advantageous for miniaturization. In particular, since the cylindrical member having an internal passage for supplying oil does not protrude into the cylinder hole, the inner end of the cylindrical member does not come into contact with internal parts such as the piston. Therefore, the first hole and the cylindrical member can be arranged in a portion of the cylinder body close to the piston, and the gaps communicating with the internal passage and the second hole can be concentrated and opened in the vicinity of the piston. As a result, even if the cylinder hole is shortened to reduce the size of the cylinder body and improve air removal performance, the entire device can be made compact so that it can be installed in a small, limited space.

On the other hand, in terms of air bleeding, at least a part of the opening of the oil supply passage directly faces the cylinder hole, so during air bleeding, the oil can drain the air inside the cylinder hole. It penetrates deep into the liquid chamber without much stirring. Another problem is that during air bleeding, the flow of oil entering the liquid chamber and the flow of air trying to escape from the liquid chamber rarely intersect, so air may be disturbed inside the liquid chamber. Less is.
With these features, air entrainment can be minimized and air can be removed satisfactorily. In particular, since the cylindrical member having an internal passage is fixed to the cylinder body side by screw connection or the like, the gap between the inner and short outer circumferences of the cylindrical member can be set accurately. The voids provide resistance to air flow and help keep the air flow from intersecting the oil flow.

Furthermore, the inner end of the second hole, which serves as an air vent passage,
Opening the cylinder hole on the axial side closer to the piston not only has the effect of reducing air disturbance, but also allows the bleeder screw to be placed along the top of the cylinder body. This also avoids the problem of the bleeder screw increasing the effective length of the cylinder device, and is advantageous in terms of miniaturization of the cylinder device.

(Example) The attached drawing shows a cross-sectional structure of a clutch operating cylinder to which this invention is applied.

A clutch operating cylinder 1, which is a cylinder device, includes a cylinder body 3 in which a cylinder hole 2 is formed. The cylinder hole 2 is open on the cylinder head 4 side located on the right side in the figure, and closed on the left side of the cylinder bottom 5 side. The opening 6 on the cylinder head 4 side is covered by a rubber boot 7. The boot 7 has a thick outer circumferential portion 7a that fits into an outer circumferential groove 8 provided in the cylinder body 3, and a thick inner circumferential portion 7b that fits into the push rod 9.
It fits into a groove 10 provided in the. The push rod 9 is provided along the axis of the cylinder hole 2, and its right end 9a protrudes outside the boot 7, while its left end 9b extends toward the piston inside the cylinder hole 2. It is in contact with the bottom surface of the right side recess 12 of 11. Therefore, the push rod 9 is driven by the piston 11 and can move forward to the right. This movement of the push rod 9 provides a driving force for a clutch operating arm (not shown), thereby making it possible to disconnect the clutch.

The piston 11 that slides inside the cylinder hole 2 consists of a large diameter portion 13 that matches the size of the cylinder hole 2 and a small diameter portion 14 that is smaller in diameter.
A seal ring 15 is attached to the. The seal ring 15 is fitted between the left side surface 13a of the piston large diameter portion 13 and the projection 14a of the small diameter portion 14, and the outer circumferential lip portion 15a is in close contact with the inner circumferential wall of the cylinder hole 2. As a result, a liquid chamber 16 is formed inside the cylinder hole 2 to the left of the piston 11. A plastic retainer ring 17 in the liquid chamber 16 is used to prevent the lip portion 15a of the seal ring 15 from falling radially inward during vacuum breathing. Note that the retainer ring 17 is lightly pressed against the cylinder bottom 5 side by a conical spring 18.

Now, the liquid chamber 16 facing the cylinder bottom 5 communicates with two holes that connect the liquid chamber 16 to the outside.

One is a first hole 19 that is substantially perpendicular to the cylinder hole 2, and the other is a second hole 20 that runs obliquely to the cylinder hole 2. Both the first and second holes 19 and 20 are connected to the cylinder body 3.
It is provided by processing. The first hole 19 has a substantially uniform diameter throughout, and has a normal cylindrical shape on the side closer to the liquid chamber 16, while the other portion adjacent thereto has a female threaded portion 19a. Further, the second hole 20 has a small diameter hole 21 on the side closer to the liquid chamber 16 and a side closer to the liquid chamber 16.
The side farthest from 6 is a large diameter hole 22. Large diameter hole 2
The part 2 is a part into which the bleeder screw 23 is screwed, and there is a conical seat 22a at the boundary with the small diameter hole 21, and a female threaded part 22b from the middle of the inner circumferential side to the outside. The bleeder screw 23 screwed into the large-diameter hole 22 has a T-shaped passage 24 therein, and has a conical portion 23a at its tip that comes into close contact with the conical seat 22a. The bleeder screw 23 has a conical tip portion 23a that is connected to the conical seat 2.
By being in close contact with 2a, the side of the small diameter hole 21 is isolated from the outside air, and by being away from the conical seat 22a, the side of the small diameter hole 21 is communicated with the outside air.

Further, a cylindrical member 26 having an L-shaped internal passage 25 is attached to the first hole 19 . The cylindrical member 26 has a tip portion 26a having a slightly smaller diameter than the cylindrical portion 19b of the first hole 19, and an upper male threaded portion 26b of the cylindrical member 26 has a diameter slightly smaller than that of the cylindrical portion 19b of the first hole 19.
Compatible with This cylindrical member 26 has a head 26c
A ring-shaped joint member 27 is screwed between the lower surface and the upper surface of the cylinder body 3, and seal rings 28 and 29 are sandwiched between the upper and lower surfaces of the joint member 27. A pipe 30 communicating with the master cylinder is connected to the side of the joint member 27, and an end 30a of the pipe 30 is connected to the upper opening 25a of the internal passage 25.
is familiar with On the other hand, the lower opening 25b of the internal passage 25 in the cylindrical member 26 faces the liquid chamber 16.

The internal passage 25 becomes an oil supply passage, but since its lower opening 25b directly faces the cylinder hole 2 or the liquid chamber 16, the oil to be supplied is supplied to the liquid chamber 1.
It can be sent deep into the interior of 6. Also,
The inner end of the cylindrical member 26 with the lower opening 25b faces the cylinder hole 2, but does not protrude into the cylinder hole 2. Therefore, the cylindrical member 26 is connected to the retainer ring 17 in the cylinder hole 2 and the piston 1.
There is no interference with 1 etc. Therefore, at least a portion of the cylindrical member 26 can be arranged within the stroke of the piston 11, the cylinder hole 2 is correspondingly short, and the cylinder device 1 is compact. In the example shown in the figure, there is a retainer ring 17 inside the liquid chamber 16, so in order to prevent interference with it, the lower opening 25b is placed slightly closer to the cylinder bottom 5. If not, open the lower opening 2.
Of course, the entire portion 5b can be made to face the liquid chamber 16.

Here, since the tip portion 26a of the cylindrical member 26 near the liquid chamber 16 has a slightly smaller diameter than the first hole 19, a small ring-shaped gap 31 is formed on the outer periphery of the tip portion 26a. The void 31
The inner end 21 of the small diameter hole 21 of the second hole 20
a is open. In this case, it should be noted that the opening 21a of the small diameter hole 21 with respect to the space 31 is arranged on the axial side of the cylinder hole 2 closer to the piston 13. During the air bleeding operation, the air that escapes from the liquid chamber 16 exits through the opening 21a, so it does not intersect with the flow of the supplied oil, and is therefore not disturbed and relatively Move smoothly. In particular, since the cylindrical member 26 itself is fixed to the cylinder body 3 by screw connection, the gap 31 around the tip portion 26a can be set accurately. This gap 31 acts as a resistance to the flow of air, and is therefore effective in reducing the flow of air that intersects with the flow of oil.

Therefore, when filling the liquid chamber 16 with oil by the pressure feeding method or the pumping method, the oil flowing from the master cylinder side passes through the inside of the pipe 30 and the internal passage 25 of the cylindrical member 26, and the oil flows into the inside of the cylindrical member 26. The liquid is smoothly supplied into the liquid chamber 16 in the form of a rod from the opening portion 25b at the end. Along with this, the air in the liquid chamber 16 flows from around the supplied oil into the ring-shaped gap 31, especially mainly through the opening 21a.
It reaches the small diameter hole 21 from the side closest to the bleeder screw 23, and is further discharged to the outside through the internal passage 25 of the bleeder screw 23. Therefore, since the oil and air flows are well separated, air and oil can be replaced with almost no entrainment of air.

(Effects of the invention) In this invention, the opening of the air bleed passage is placed on the outer periphery of the oil supply port, so it is possible to reduce the size of the cylinder device and effectively solve the problem of air entrainment. Can be done. In particular, this design makes it possible to supply oil deep into the liquid chamber, and also prevents the oil supplied into the liquid chamber and the air flowing out from the liquid chamber from intersecting each other. can be effectively separated, thereby allowing air to be removed effectively. Moreover, since the cylindrical member with the internal passage for oil supply is arranged so that it does not come into contact with the internal parts inside the cylinder hole, both openings for air bleeding and oil supply can be concentrated in the vicinity of the piston. , the cylinder device can be made compact.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of this invention. DESCRIPTION OF SYMBOLS 1...Clutch operating cylinder (cylinder device), 2...Cylinder hole, 3...Cylinder body, 11...Piston, 16...Liquid chamber, 19
. . . first hole, 20 .

Claims (1)

[Scope of utility model registration request] a cylinder body having a cylinder hole with at least one end open; a piston slidably inserted into the cylinder hole; a liquid chamber defined within the cylinder hole; The cylinder has a first hole and a second hole formed in the cylinder body, the first hole is connected to piping from the master cylinder, and the second hole is closed by screwing a bleeder screw. In the apparatus, a cylindrical member having an internal passage and an inner end extending toward the liquid chamber is fixed and attached to the first hole at a constant height such that the inner end is located within the first hole, and the cylindrical member A gap is formed between the outer periphery of the inner end and the inner wall of the first hole, and the inner end of the second hole is opened in the gap, and at least a part of the inner opening of the inner passage directly faces the cylinder hole, and further, the inner end of the second hole opens into the gap on the axial side of the cylinder hole closer to the piston.