JP2010266037A - Seal groove forming method and disc brake having seal groove formed using the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seal groove forming method which can easily control the dimensions of a seal groove by using a formed turning tool having a special cutting edge shape when the seal groove is formed, and to provide a disc brake with the seal groove formed using the method. <P>SOLUTION: In the method of machining a piston seal groove on the inner surface of a cylinder, the seal groove 4 is machined using the formed turning tool for machining a seal groove portion which has a cutting edge 5 forming a level difference 6 at least either ahead or behind the groove portion in the axial direction. The approximate depth of the level difference is 0.2 mm, and the length of the level difference is approximately 2 mm. The level difference is formed of either flat surfaces or curved surfaces. The piston seal groove for the disc brake which is machined inside the cylinder is machined by the seal groove machining method for disc brake production. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for forming a seal groove formed on a cylinder side in a structure in which a gap between a cylinder and a piston is sealed with a seal member, and a disc brake in which a seal groove is formed on the inner surface of the cylinder using the method. .

In FIG. 8, in a conventionally known disc brake or the like, a piston 23 for pressing a pair of brake pads 22 arranged on both sides via a disc 21 is provided on a bottomed cylindrical cylinder 25 of a caliper. The hydraulic pressure is introduced into the hydraulic pressure chamber 26 formed by the cylinder bore formed in the cylinder and the piston 23 so that the piston 23 moves and presses the brake pad 22. It has become.
Between the piston 23 and the cylinder 25, there is provided a seal member (retract seal) 27 composed of a square ring having a square cross section made of a rubber material or the like for sealing between the two. The seal member 27 is assembled in contact with a bottom surface portion in a seal groove 28 provided around the cylinder bore, and the seal groove 28 is formed so that the cross section in the axial direction of the cylinder 25 has a substantially trapezoidal shape. ing. In addition to sealing between the piston 23 and the cylinder 25, the seal member 27 assembled in the seal groove 28 has a function of returning a predetermined amount of the piston propelled in the disk direction during braking toward the hydraulic chamber when releasing the brake (rollback). Function), an auto adjuster function corresponding to pad wear, a shake back preventing function for preventing the piston from moving due to vibration, and the like (Patent Document 1). That is, if the pad is not pulled away from the disk rotor during non-braking, a drag phenomenon occurs on the pad.
Further, since the seal groove and the seal member are required to have the above functions, the processing accuracy on the seal groove side is also required to be extremely high.

Japanese Patent Laid-Open No. 06-117462

In the conventional disc brake, the seal groove provided around the normal cylinder bore is formed as follows.
In FIG. 5, in order to form the seal groove, a general cutting tool (hereinafter, referred to as a general cutting tool) 1 as shown in FIG. 5 is generally used, and the total cutting tool 1 is rotated along the inner peripheral surface of the cylinder bore. However, the sealing groove is formed while feeding the complete bit 1 into the cylinder wall little by little as shown by the arrow, and finally the same shape as the cross section of the full bit 1 as shown by the solid line in the figure Is formed on the inner wall surface of the cylinder.
By the way, although the sealing groove formed by the overall cutting tool 1 has high processing accuracy, various problems have been pointed out in measuring the dimension of the sealing groove after actual processing.
That is, as shown in FIG. 6, the bottom of the seal groove is an inclined surface for increasing the airtightness by controlling the rollback amount and changing the seal interference between the hydraulic side and the anti-hydraulic side. Yes. Therefore, in measuring the bottom dimension of the seal, it is difficult to apply a terminal such as a caliper gauge to the two surfaces A and B in FIG. 6, and measurement errors are likely to occur. Moreover, this method has to be adopted for the C and D surfaces, and there is a problem that it takes time.
In addition to this, as shown in FIG. 7, a seal groove is molded using a resin, and the resin is measured with a microscope to measure the dimensions of the seal groove (X, Y, Z). However, it takes several hours to measure and is not practical.

  Accordingly, the present invention provides a seal groove forming method capable of easily managing the dimensions of the seal groove by using a general cutting tool having a special blade shape when forming the seal groove, and a seal groove using the method. It is an object of the present invention to provide a disc brake having a shape.

For this reason, means for solving the problems adopted by the present invention are:
A method of machining a piston seal groove on an inner surface of a cylinder, wherein the seal groove is machined by a total cutting tool for machining a seal groove having a blade that forms a step on at least one of front and rear in the axial direction of the groove. This is a method for processing a seal groove part.
The step is approximately 0.2 mm in depth and about 2 mm in length, and the step is formed by either a flat surface or a curved surface.
In addition, the present invention provides a disc brake characterized in that a piston seal groove to be machined in a disc brake cylinder is machined by the seal groove machining method.
Further, the disc brake is characterized in that a step is formed at least in either the front or rear of the seal groove in the axial direction of the piston seal groove processed in the cylinder for the disc brake.

  According to the present invention, it is possible to obtain the same dimensional accuracy as that obtained by measuring the dimension of the entire seal groove only by measuring the dimension of a part of the seal groove formed by a general cutting tool having a special blade shape. In particular, the total bite can have a relative accuracy of within ± 0.01 mm, so just measuring the dimensions of a part of the seal groove has the same effect as measuring the dimensions of the entire seal groove. It is possible to achieve unique and advantageous effects such as being able to obtain and simplifying the measurement of the seal groove.

It is a figure explaining the method of forming the sealing groove | channel which provided the level | step difference after the sealing groove | channel using the general shape bite as 1st Example which concerns on this invention. It is explanatory drawing which measures the dimension of the formed seal groove. It is a figure explaining the method of forming the sealing groove | channel which provided the level | step difference in front of the sealing groove | channel using the total shape bite as 2nd Example which concerns on this invention. It is explanatory drawing which measures the dimension of the formed seal groove. It is explanatory drawing of the formation method of the sealing groove | channel by the conventional general shape tool. It is explanatory drawing of the dimension measurement of the seal groove | channel formed with the conventional general shape bite. It is explanatory drawing of the dimension measurement of what took the sealing groove | channel using resin. It is a block diagram of a conventionally known disc brake.

The present invention relates to a method of machining a piston seal groove on the inner surface of a cylinder, wherein the seal groove is formed by a general-purpose bite having a blade that forms a step on at least one of front and rear of the groove portion in the rotor axial direction. It is characterized by processing. Here, the front means the rotor side of the seal groove, and the rear means the cylinder bottom side of the seal groove.
In addition, there is a feature in the disc brake in which the seal groove is processed using the processing method.

Embodiments of a seal groove forming method according to the present invention and a disc brake having a seal groove formed using the method will be described below with reference to the drawings.
FIG. 1 is an explanatory view of a method of forming a seal groove according to the first embodiment of the present invention.
In the figure, reference numeral 2 denotes a cylinder member for forming a seal groove, and reference numeral 3 denotes a cylinder inner peripheral surface.
In order to form the seal groove 4 on the cylinder inner peripheral surface 3, it is formed by the total shape bit 1 as in the prior art. The total shape bit 1 used at this time is one side of the seal groove 4 as shown in FIG. A tool having a blade 5 for slightly cutting (right side in the figure) from the inner peripheral surface of the cylinder is used. The blade 5 only needs to be capable of forming a step on either side of the seal groove, and the step may be flat or curved.
Specifically, a blade part capable of forming a step of about 2 mm in length and about 0.2 mm in depth on the cylinder inner peripheral surface of the seal groove 4 on the hydraulic side or the counter-hydraulic side is formed in the overall cutting tool.

When the sealing groove 4 is machined with the complete cutting tool having the blade 5 forming the step as described above, a step due to the blade 5 is formed on at least one side of the completed sealing groove (see FIG. 2). By measuring the dimension of the step formed in this way with the caliper 7, the (X, Y) dimension of the seal groove 4 can be known. This is because the total form bite has an accuracy within ± 0.01 mm, so that there is no particular problem in estimating the (X, Y) size of the seal groove 4 by measuring the step size. Moreover, it is easy to measure the size of the step, and the measurement can be performed only once, and the time can be reduced.
By forming the seal groove on the cylinder inner surface of the conventional disc brake by the above-described seal groove forming method, it is possible to easily form an accurate seal groove on the disc brake cylinder inner surface.

FIG. 3 is an explanatory view of a method of forming a seal groove according to the second embodiment of the present invention.
The second embodiment is an example in which the seal groove is formed by a complete cutting tool having a blade 5 on the rotor side of the seal groove. When the step 6 is formed on the rotor side of the seal groove, the portion A in FIG. 3 cannot be cut in order to keep the rollback amount unchanged. Therefore, the step portion 6 is formed at a position slightly away from the seal groove 4 as shown in the figure.
When the step is formed with the overall cutting tool shown in the drawing, the dimension of the step portion can be estimated with a caliper as in the first embodiment, and the size of the seal groove can be estimated as in the first embodiment. .
The blade 5 only needs to be capable of forming a step on the rotor side of the seal groove, and the step may be flat or curved.

  While the embodiments of the present invention have been described above, the shape of the stepped portion (plane, curved surface, etc.) can be changed as appropriate within the scope of the gist of the present invention. The specifications described in the examples are merely examples in all respects and should not be interpreted in a limited manner.

  The present invention can be used for processing a seal groove of a vehicle disc brake.

1 Complete Bit 2 Cylinder 3 Cylinder Inner Surface 4 Seal Groove 5 Blade 6 Step 7 Caliper

Claims (4)

A method of machining a piston seal groove on an inner surface of a cylinder, wherein the seal groove is machined by a total cutting tool for machining a seal groove having a blade that forms a step on at least one of front and rear in the axial direction of the groove. A seal groove processing method characterized by the above. The seal groove processing method according to claim 1, wherein the step has a depth of approximately 0.2 mm and a length of approximately 2 mm, and the step is formed by a flat surface or a curved surface. 3. A disc brake characterized in that a piston seal groove to be machined in a disc brake cylinder is machined by the seal groove machining method according to claim 1 or 2. A disc brake characterized in that a step is formed in at least one of front and rear of the seal groove in the axial direction of a piston seal groove to be machined in a disc brake cylinder.

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