JP4535606B2 - Piston cup - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piston cup in which a built-up portion is provided on the back side of an outer peripheral portion provided with a flow groove through which hydraulic fluid passes, and a thin portion generated by the flow groove is replenished.
[0002]
[Prior art]
Various hydraulic devices are mounted on vehicles, particularly automobiles. These hydraulic devices attach a piston cup to the piston, seal between the piston and the cylinder, distribute the working oil, press the working oil by the piston, send it back to various devices, and return them. To operate. On the other hand, hydraulic brake systems that use liquid (hydraulic oil) for power transmission have many advantages such as excellent response, simple structure and high design freedom. Yes. In this hydraulic brake system, a piston cup that ensures sealing performance and flowability between the piston and the cylinder is regarded as important from the viewpoint of safety.
[0003]
If there is a problem with the sealing performance of the piston cup, it means that even if the brake pedal is depressed, the force cannot be sufficiently transmitted to the hydraulic oil by the piston, and the hydraulic brake cannot be sufficiently operated. On the other hand, if there is a problem in the flowability, it means that even if the brake pedal is released, the piston does not return smoothly and the hydraulic brake is not released sufficiently. Therefore, not only the sealing performance but also the flowability of the piston cup is important, and at the same time its durability is required.
[0004]
As shown in FIG. 7, the conventional piston cup 50 includes a lip portion 53 that slides on the inner peripheral surface of the cylinder 51 to seal between the piston 52 and the cylinder 51, and a mounting portion for mounting the piston 52. 54. A ring 56 smaller than the diameter is applied to the base surface 55 of the piston cup 50 so that the rigidity of the piston cup 50 is secured, and the piston cup 50 is sufficiently secured. . On the other hand, a flow groove 57 is provided at the boundary between the lip portion 53 and the base surface 55 to ensure the flowability thereof.
[0005]
[Problems to be solved by the invention]
However, although the above-described piston cup 50 is provided with the flow groove 57 at the boundary between the lip portion 53 and the base surface 55 and can contribute to the flow and improve the flowability, the flow groove 57 is provided. The portion becomes thin, and stress concentrates and swells in the thin portion, which is easily damaged. Further, there is a problem in that the peripheral portion 56a of the ring 56 comes into contact with the base surface 55 due to continuous use, starts to be worn and scratched, and finally a tear occurs.
[0006]
As described above, when these thin-walled portions are broken or ruptured, hydraulic oil leaks from the thin-walled portion and the hydraulic brake cannot be fully operated, which may lead to a serious accident. In order to prevent this, it is conceivable to change the material of the piston cup 50 to a tough material or a material that is difficult to wear, or to attach an R (R) to the peripheral edge 56a of the ring 56 to make it difficult to wear. Just responding to it will last a little longer and will not be a fundamental solution. Therefore, the conventional piston cup 50 needs to be regularly replaced.
[0007]
Therefore, the object of the present invention is that there is a thin wall portion associated with the flow groove, and even if a ring is applied to the base surface, it will not be damaged or scratched, causing a worst-case tear and is durable. The object is to provide a piston cup with excellent properties.
[0008]
[Means for Solving the Problems]
The present invention has been proposed in order to achieve the above object, and is characterized by having the following configuration.
That is, according to the present invention, the piston cup is mounted on a piston to seal between the piston and the cylinder, and has a flow groove through which hydraulic fluid passes on the outer periphery, and the flow groove is provided in the piston cup. A piston cup is provided in which a built-up portion is provided on the back side of the outer peripheral portion and a thin portion generated by the flow groove is replenished.
[0009]
Moreover, according to this invention, the said piston cup in which the said build-up part is formed in the magnitude | size equivalent to the said flow groove at least is provided.
[0010]
Moreover, according to this invention, the said piston cup which provided R (R) in the boundary of this and the said outer peripheral part in the said flow groove is provided.
[0011]
Moreover, according to this invention, the ring-shaped groove | channel is provided in the base surface formed in the piston side in the piston cup of any one of the said Claim 1 thru | or 3, and the peripheral part of the ring which supports the said piston cup is said A piston cup is provided in which the peripheral edge portion is not in contact with the base surface so as to be positioned in the ring-shaped groove.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view of a brake master cylinder incorporating a piston cup showing an embodiment of the present invention, FIG. 2 is a cross-sectional view of a piston cup showing the embodiment of the present invention and its periphery, and FIG. It is a top view of the piston cup which shows this embodiment. In the figure, reference numeral 1 denotes a tandem type brake master cylinder. In the brake master cylinder 1, first and second pistons 4 and 5 are slidably fitted in a bore 3 of the cylinder 2. . A first return spring 7 is mounted between one end of the first piston 4 and the bore bottom 6, and the first piston 4 is stopped at a set position by a stopper (not shown). Similarly, a second return spring 8 is mounted between the other end side of the first piston 4 and one end side of the second piston 5, and the other end side of the second piston 5 is fitted to the bore port 9. The wheel 10 is stopped at the set position.
[0013]
A first pressure cup 11 is fitted on the other end side of the first piston 4, and the inside of the bore 3 of the cylinder 2 is liquid-tightly divided into a region of the first piston 4 and a region of the second piston 5. The second pressure cup 12 is fitted to the other end portion side of the second piston 5, and the region of the second piston 5 and the atmosphere are shut off. A push rod (not shown) is pressed into the hole 13 on the other end side of the second piston 5, and this push rod is connected to a brake pedal (not shown) via a booster or the like. is doing.
[0014]
A first piston cup 20 is fitted to one end of the first piston 4, and the region of the first piston 4 is divided into a first pressure chamber 21 and a first supply chamber 22 with the first piston cup 20 as a boundary. Closely divided. Similarly, a second piston cup 23 is fitted to one end of the second piston 5, and the region of the second piston 5 is separated from the second pressure chamber 24 and the second supply chamber 25 with the second piston cup 23 as a boundary. And liquid-tight. The first pressure chamber 21 and the first replenishment chamber 22 communicate with each other during the return process through a hole 26 formed in the first piston 4.
[0015]
Similarly, the second pressure chamber 24 and the second supply chamber 25 communicate with each other during the return process through a hole 27 formed in the second piston 5. Similarly, the first piston cup 20 is caused by the elastic force of the first return spring 7 transmitted by the stopper metal 28, and the second piston cup 23 is similarly elastically generated by the second return spring 8 transmitted by the stopper metal 29. The force prevents the first piston 4 and the second piston 5 from falling off during the return process.
[0016]
Further, the cylinder 2 constituting the region of the first piston 4 is provided with a first reservoir 30 and a passage 31, and the first reservoir 30 is connected to the first pressure chamber 21 and the first supply chamber 22 by ports 32 and 33. The passage 31 is connected to a brake device or a clutch device, for example, through a pipeline (not shown). Similarly, the cylinder 2 constituting the region of the second piston 5 is provided with a second reservoir 34 and a passage 35, and the second reservoir 34 is connected to the second pressure chamber 24 and the first supply chamber 25 by ports 36 and 37. linked. The passage 35 passes through a pipeline (not shown) similarly to the passage 31, and is connected to, for example, a brake device or a clutch device.
[0017]
The first and second piston cups 20 and 23 are exactly the same in shape and action. Although the first and second pressure cups 11 and 12 have different shapes, they have substantially the same action and substantially the same action as the first and second piston cups 20 and 23 except that the pumping action described later is not performed. .
[0018]
Next, the first piston cup 20 (hereinafter simply referred to as the piston cup 20) will be described in detail.
The piston cup 20 is attached to the first piston 4 to seal between the first piston 4 and the cylinder 2, and the base surface 40 formed on the first piston 4 side of the piston cup 20, the first piston 4, A ring 41 for supporting the piston cup 20 is interposed between the outer peripheral portion 43 and the outer peripheral portion 43 of the outer peripheral portion 43 provided with the flow groove 42. A raised portion 44 is provided to replenish a thin portion caused by the flow groove 42.
[0019]
Since the build-up portion 44 is formed to supplement the thinning of the portion by the flow groove 42 formed on the surface side, at least the size of the flow groove (corresponding to the volume) ) Is preferably supplemented.
[0020]
The piston cup 20 has a ring shape, and naturally has a lip portion 45 that slides on the inner peripheral surface of the bore 3 of the cylinder 2 to seal between the first piston 4 and the cylinder 2. 4, and one end portion of the first piston 4 is fitted into the mounting portion 46. The lip portion 45 needs not only a sealing action but also a pumping action. This pumping action may be caused when the first piston 4 returns to the negative pressure in the first pressurizing chamber 21, in which case the lip portion 45 is deflected inward of the bore 3 and the hydraulic fluid is replenished. One piston 4 can be returned smoothly.
[0021]
Therefore, the lip portion 45 has a slight pumping action, that is, the outer peripheral portion 43 of the piston cup 20, more precisely, at the boundary between the lip portion 45 and the base surface 40, so that the hydraulic oil is replenished even with a slight deflection. A total of six circulation grooves 42 are provided at every 60 degrees, and these circulation grooves 42 assist the replenishment of hydraulic oil. And the thin-walled part by having the circulation groove | channel 42 carved is replenished by the said build-up part 44, and, thereby, damage is prevented. Further, as shown in FIGS. 4 and 5, the circulation groove 42 is provided with an R (R) at a corner portion to increase durability.
[0022]
On the other hand, the ring 41 is necessary to support both the above-described actions in the piston cup 20, and the ring 41 is provided in close contact with the base surface 40 of the piston cup 20. One end of the first piston 4 is fitted into the ring 41 together with the piston cup 20, and only the surface of the ring 41 comes into contact with the step 4 a formed by the large diameter portion and the medium diameter portion of the first piston 4. For this reason, the peripheral portion 41a of the ring 41 hits against the base surface 40 due to the pressure from the first pressure chamber 21 and wears it, resulting in scratches and worst-case tears. Therefore, as shown in FIG. Is provided with a ring-shaped groove 47. Therefore, the peripheral edge portion 41a of the ring 41 is not directly contacted with the base surface 40 by the ring-shaped groove 47 and is not worn. The rings 41 and 56 are made of a metal such as stainless steel or a plate material such as a hard resin. Further, in order to prevent the piston cup from being scratched by the outer peripheral edge portion of the ring, the outer peripheral portion of the ring may be chamfered such as an R shape.
[0023]
Next, the operation of the piston cup 20 configured as described above will be described with reference to the tandem type brake master cylinder 1.
FIG. 1 shows a state in which the brake master cylinder 1 is not in operation. When the driver steps on the brake pedal from this state, the force is transmitted to the push rod via a booster or the like. Since the piston 5 is pushed in the direction of the arrow A and the first piston 4 is also pushed in the direction of the arrow A, when the first and second piston cups 20 and 23 pass the ports 32 and 36, the first and second reservoirs 30 are pushed. And 34 are shut off, the first and second pressure chambers 21 and 24 are sealed and the pressure rises, and the hydraulic oil in these pressure chambers 21 and 24 passes from the passages 31 and 35 through the pipelines, for example, brakes. After that, the braking action according to the brake pedal depression force is performed.
[0024]
When the braking is released, the first and second pistons 4 and 5 are moved in the direction of the arrow B by the pressure in the first and second pressure chambers 21 and 24 and the spring force of the first and second return springs 7 and 8. Back in the direction. At that time, a negative pressure is transiently generated in the first and second pressure chambers 21 and 24, but the first and second piston cups 20 and 23 are caused to be pressurized by the pressurization from the first and second reservoirs 30 and 34. The hydraulic oil in the first and second supply chambers 22 and 25 passes through the holes 26 and 27 and is quickly sent to the first and second pressure chambers 21 and 24 with the help of the bending groove 42 and the negative pressure. Is eliminated, and the first and second pistons 4 and 5 return smoothly.
[0025]
When the first and second pistons 4 and 5 are further returned until the first and second piston cups 20 and 23 pass through the ports 32 and 36, the first and second pressure chambers 21 and 24 are sealed. Is released, the excess hydraulic oil returns to the first and second reservoirs 30 and 34, and the brake master cylinder 1 returns to the state shown in FIG.
[0026]
Thus, even if the first and second piston cups 20 and 23 perform the sealing action and the pumping action each time the brake pedal is depressed, the above-described built-up portion 44 is provided on the back side of the flow groove 42, and the flow groove is further provided. It does not swell due to 42 R (R), and it is not damaged, and durability is increased. Further, since the peripheral edge portion 41a of the ring 41 has the ring-shaped groove 47, it does not directly contact the base surfaces 40 of the first and second piston cups 20 and 23 and is not worn.
[0027]
The embodiment of the present invention has been described above, but the specific configuration is not limited to this, and can be changed or added as appropriate or other combinations in each claim can be made without departing from the gist of the present invention. That should be understood.
[0028]
【The invention's effect】
As described above in detail, according to the invention of claim 1, by providing the flow groove, the built-up portion is provided on the back side of the position to be the thin-walled portion, so that the flow groove does not swell and stress is also increased. It won't concentrate and won't break. Therefore, even if there is a circulation groove, there is an effect that it is not damaged and is excellent in durability.
[0029]
Moreover, Claim 2 prescribes | regulates the magnitude | size of a build-up part, Thereby, the formation significance of a build-up part becomes clear, and by the radius of the boundary of the distribution | circulation groove | channel and an outer peripheral part in Claim 3, The effect is that the pressure is dispersed and is difficult to break.
[0030]
According to the invention of claim 4, the peripheral edge of the ring does not hit the base surface due to the ring-shaped groove, and the base surface is hardly worn and scratched. Therefore, in addition to the effects described above, even if a ring is applied to the base surface, it is excellent in durability without being damaged or scratched and causing a worst-case tear.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a master cylinder for a brake incorporating a piston cup showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a piston cup and its surroundings showing an embodiment of the present invention.
FIG. 3 is a plan view of a piston cup showing the embodiment of the present invention.
FIG. 4 is a cross-sectional view in which a part of the piston cup showing the embodiment of the present invention is broken.
FIG. 5 is a plan view in which a part of the piston cup showing the embodiment of the present invention is broken.
FIG. 6 is a cross-sectional view of a piston cup and its surroundings showing another embodiment of the present invention.
FIG. 7 is a cross-sectional view showing a conventional example.
[Explanation of symbols]
1 Brake Master Cylinder 2, 51 Cylinder 3 Bore 4 First Piston 4a, 5a Step 5 Second Piston 6 Bore Bottom 7 First Return Spring 8 Second Return Spring 9 Bore Port 10 Retaining Ring 11 First Pressure Cup 12 Second Pressure cup 13 hole 20, 50 1st piston cup (piston cup)
21 First pressure chamber 22 First supply chamber 23 Second piston cup (piston cup)
24 Second pressure chamber 25 Second supply chamber 26, 27 Holes 28, 29 Fastener 30 First reservoir 31, 35 Passage 32, 33, 36, 37 Port 34 Second reservoir 40, 55 Base surface 41, 56 Ring 41a, 56a Peripheral part 42, 57 Flowing groove 43 Outer peripheral part 44 Overlaying part 45, 53 Lip part 46, 54 Mounting part 47 Ring-shaped groove 52 Piston A, B Arrow line R

Claims (4)

A piston cup which is attached to a piston and seals between the piston and the cylinder, and has a flow groove through which hydraulic fluid passes through an outer peripheral portion, and a build-up portion on the back side of the outer peripheral portion provided with the flow groove A piston cup, wherein a thin portion generated by the flow groove is replenished. The piston cup according to claim 1, wherein the build-up portion is formed in a size corresponding to at least the flow groove. The piston cup according to claim 1 or 2, wherein an R (R) is provided in a boundary between the circulation groove and the outer peripheral portion. 3. A ring-shaped groove is provided on a base surface formed on the piston side of the piston cup according to claim 1 or 2, and the peripheral edge of the ring that supports the piston cup is positioned in the ring-shaped groove. A piston cup characterized in that is not in contact with the base surface.

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