JPH0454327A - Disc brake - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a disc brake installed in an automobile or the like.

(Prior Art) In recent years, there has been a strong demand for improving the fuel consumption rate (fuel efficiency) of automobiles when they are running. Therefore, various measures have been taken to improve fuel efficiency, such as improving power performance by improving the engine and reducing running resistance by improving the body shape. Furthermore, since reducing the acceleration resistance during acceleration of an automobile greatly contributes to improving fuel efficiency, efforts are being made to reduce vehicle weight, which directly affects acceleration resistance.

Conventionally, one way to reduce vehicle weight is to reduce the weight of disc brakes installed in automobiles. The caliper, which is a part of the floating type disc brake, is made up of a cylinder side member that is supported by a piston that presses the inner pad against the disc, a disc bus part that straddles the disc, and a claw part that engages with the outer butt. It is composed of two members, a side member and a side member, and each member is fixed by bolts passing through the cylinder side member from the axial direction of the disk, screwing into the disk bus portion, and tightening. Furthermore, the cylinder side member is made of a light alloy such as an aluminum alloy, and the pawl side member is made of iron, thereby reducing the weight of the caliper. In addition, the disc bus part of the claw side member is located in the narrow gap between the wheel and the disc, so it is not possible to increase the plate thickness, and the claw part requires great strength because it presses against the outer pad. Therefore, the claw side member is made of iron with high rigidity.

(Problems to be Solved by the Invention) However, the conventional caliper described above had the following problems.

In the above caliper, a bending moment is created in each of the cylinder side member and the pawl side member that tends to open outward due to the reaction force when the butt or disc is pressed during braking.
As a result, compressive force is applied to the joint surface between the cylinder side member and the claw side member, and there is a risk that the joint surface of the cylinder side member, which has low rigidity, may become soaked.To prevent this, the joint surface of the cylinder side member and the claw side member A built-up portion is provided on the outside of the joint to increase the area of the joint surface, thereby reducing surface pressure (force applied per unit area of the joint surface). However, the point of intersection between the outer surface of this built-up part and the outer surface of the claw side member is an inflection point, and the stress due to the bending moment is concentrated at this point, causing it to bend significantly from this point. Dari,
In the worst case, there was a problem in that cracks etc. would occur at this location. In addition, it may be possible to form the built-up part smoothly to avoid inflection points, or to widen it outwards since the wheel faces the outside of the caliper with a small gap as mentioned above. In addition, there is a disk placed on the inside, and if this disk is made smaller, problems such as a decrease in braking performance and a lack of heat capacity of the disk will occur, so it is not possible to expand it inside as well. , it is impossible to prevent the occurrence of inflection points.

The present invention has been made in view of the above problems, and its purpose is to provide a disc brake with a split caliper that prevents stress from being concentrated at the inflection point caused by the built-up portion. It's about doing.

(Means for Solving the Problems) The present invention provides a caliper that is supported in a floating state on a non-rotating part of a vehicle body, a cylinder side member that is supported by a piston that presses an inner pad against a disk, and a disk bus section that straddles the disk. and a claw side member consisting of a claw portion that engages with the outer pad, and each member is fixed by a bolt that passes through the cylinder side member from the axial direction of the disk and is screwed into the disk bus portion. In the disc brake, a built-up part is provided on the outside of the joining point of the cylinder side member and the claw side member, and a position where the outer surface of the built-up part of the claw side member and the outer surface of the disc bus part intersect. It is characterized in that the bolt is screwed to a position closer to the claw portion of the claw side member.

Further, the shaft of the bolt may be positioned inward from the center position in the thickness direction of the disk bus portion of the claw side member.

(Function) With the above configuration, by screwing the bolt to a position closer to the pawl than the inflection point, the bending moment generated in the cylinder side member and the pawl side member during braking is suppressed by the highly rigid bolt. Therefore, it is possible to reduce stress concentration at the point of inflection.

Furthermore, by locating the bolt axis inward from the center in the thickness direction of the disc bus section, the tensile force generated on the contact surface due to the bending moment generated on the cylinder side member and pawl side member during braking is effectively reduced. can be suppressed (force).

(Example) Next, embodiments of the present invention will be described based on the drawings.

Note that FIG. 1 is a cross-sectional view of the disc brake of this embodiment (
(I-I line sectional view in Figure 4), in Figure 2, the right side of the center line is a view in the direction of arrow A in Figure 1, the left side is a view in the direction of arrow B, and Figure 3 is a view in the direction of arrow C in Figure 1. , FIG. 4 is a view taken along arrow D in FIG.

A carrier l fixed to a non-rotating part on the body side of an automobile (not shown) has a shape that straddles a disk 2 fixed to an axle (not shown), and has a pair of legs 3° 3 provided in the rotating direction of the disk 2. , a connecting portion 4 that connects the pair of leg portions 3.3 on one side of the disk 2, and an outer beam 5 that connects the pair of legs 3.3 on the other side. Legs 3.3
Inner pad 6 and outer pad 7 are attached to disk 2.
Torque receivers for movably supporting the inner butt 6 and the outer butt 7 in the axial direction and receiving torque from the inner butt 6 and the outer butt 7 during braking are formed in portions 3a and 3a. A bat spring 8 is interposed between the carrier l and both bats 6.7, and the bat spring 8 is attached to each bat 6.
．． 7 substantially radially outward of the disk 2, and the torque receiver protects the portions 3a, 3a. Further, a caliper support bin 10.10 attached to the caliper 9 is slidably fitted into the leg portion 3.3 from the axial direction of the disc 2, so that the caliper 9 is floating on the carrier 1. Supported.

The caliper 9 is of a twist type and has a cylinder side member 1 formed with a piston 11 for pressing the inner pad 6 against the disk 2 or a cylinder 12 that is slidably fitted therein.
3, a disc bus part 14a that straddles the disc 2, and a claw part 14b that engages with the outer butt 7.
It is composed of two members: 4. The cylinder side member 13 and the claw side member 14 are divided by the same plane as the plane F of the portion of the cylinder side member 13 where the cylinder 12 opens. Here, the cylinder side member 13 is made of a light alloy such as an aluminum alloy because it does not require large rigidity, and the claw side member 14 is made of a disc bus portion 14a or a wheel (not shown) and a disc. Since it is located in a narrow gap between 2 and 2, it is difficult to increase the plate thickness, and
The claw portion 14b requires great strength to press the outer pad 7, so it is made of iron with high rigidity. In this way, the weight of the caliper 9 is reduced, thereby reducing the weight of the entire disc brake.

Four screw holes 15 are formed in the disk bus portion 14a of the claw side member 14 along the axial direction of the disk 2, and screw holes 15 are formed in the cylinder side member 13 at four locations to correspond to the positions of the screw holes 15. A through hole 16 is formed along the direction. Then, the cylinder side member 13 and the claw side member 14 are fixed by inserting the tie bolt 17 into the through hole 16, screwing it into the screw hole 15, and tightening it.

The outer side (upper side in FIG. 1) of the joined portion of the cylinder side member 13 and the claw side member 14 is built up to a certain thickness and is thicker than the other portions. This built-up portion 18.19 connects the disc 2 to both butts 6.
When the cylinder side member 13 is held by the reaction force, the cylinder side member 13
A bending moment is generated in the direction in which the claw-side member 14 widens (arrow E + force direction for the cylinder-side member 13 in FIG. 1 and E2 direction for the claw-side member 14 in FIG. 1). This is to prevent the joint surface of the cylinder side member 13 from getting soaked. An inflection point P is generated at a location where the outer surface of the built-up portion 18 of the claw side member 14 and the outer surface of the disk bus portion 14a intersect. This inflection point P occurs because, as shown in FIG. 1, the wheel profile H is located with a slight gap from the caliper 9, and the built-up portion 18 cannot be formed smoothly.

The screw hole 15 of the disk bus portion 14a consists of a pilot hole and a threaded portion. The tie bolt 17 screwed into the tapped hole 15 is at the inflection point P.
They are screwed together at a position closer to the claw portion +4b of the claw side member 14 than the above. That is, the distance X between the inflection point P and the tip of the tie bolt 17 in the axial direction of the tie bolt 17 is set to be larger than 0 (X>O).

Further, the shaft 17a of the tie bolt 17 is located at a central position 14 in the thickness direction of the disk bus portion 14a of the claw side member 14.
It is located inward from c. That is, tie bolt 1
7 is placed as close to bad 6 and 7 as possible.

The operation related to the disc brake configured as above will be explained.

First, the operation of the disc brake of this embodiment will be briefly described. When hydraulic pressure is introduced into the cylinder 12, the piston 11 moves forward and presses the inner pad 6 against the disc 2. Since the caliper 9 is held in a floating state by the caliper support bin lO on the carrier 1, the piston 1 is moved by the reaction force when it is pressed by the inner pad 6 or the disc 2.
1 moves in the opposite direction to the direction in which the outer bat 7 moves (to the left in FIG.
Braking force is generated by holding the

Incidentally, during braking in this disc brake, a reaction force generated when the pad 6.7 presses the disc 2 causes a bending moment in each of the cylinder side member 13 and the pawl side member 14 that tends to open outward. Due to this bending moment, a compressive force is applied to the joint surface between the cylinder side member 13 and the claw side member 14 on the side far from the butt 6.7, and a tensile force is applied on the side close to the butt 6.7. Therefore, in the above configuration, by forming the built-up portions 18 and 19 on the outside of the joint between the cylinder side member 13 and the pawl side member 14, the joint surface of the cylinder side member 13, which has low rigidity, will not get wet even when compressive force is applied. The area of the bonding surface is set large to prevent this.

Further, the tie bolt 17 is moved from the inflection point P to the claw side member 14.
By screwing it together to a position near the claw part 14b,
The bending moment generated in the cylinder side member 13 and the claw side member 14 is suppressed by the tie bolts 17 having high rigidity, thereby reducing stress concentration at the inflection point P. Therefore,
This can prevent large bending or cracking around the inflection point P due to bending moments.

Moreover, by locating the shaft 1.7a of the tie bolt 17 inward from the center position 14c in the thickness direction of the disc bus portion 14a of the claw side member I4, the cylinder side member 13 and the claw side member 14 are It is possible to effectively suppress the tensile force generated on the joint surface due to the bending moment generated in the joint.

By configuring as described above, the rigidity of the twist type caliper 9 as a whole can be increased.

Note that the present invention is not limited to the above embodiments,
The number of tie bolts 17, the thickness of the thick portion 20, etc. may be set as appropriate.

(Effects of the Invention) As described above in detail, the present invention provides a lightweight disc brake having a twist caliper composed of two members, a cylinder side member and a pawl side member.
A built-up part is provided on the outside of the joint between the cylinder side member and the claw side member, and the bolt is inserted beyond the inflection point where the outer surface of the built-up part of the claw side member intersects with the outer surface of the disk bus part. By screwing the claw side member closer to the claw part, this bolt suppresses the bending moment generated in the cylinder side member and the claw side member during braking, and reduces stress concentration at the point of inflection. I can do it.

In addition, by locating the bolt axis inward from the center in the thickness direction of the disc bus section, deformation due to the tensile force generated on the joint surface due to the bending moment generated on the cylinder side member and pawl side member during braking can be effectively reduced. can be suppressed to

In this way, by increasing the rigidity of the caliper without increasing its weight, the amount of deflection caused by the bending moment is reduced, and the amount of brake fluid pressure supplied can be reduced, thereby reducing the stroke of the brake pedal. It also has the effect of improving the pedal feel by making it smaller.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view (cross-sectional view taken along line I-I in FIG. 4) of a disc brake according to an embodiment of the present invention. In Figure l's2, the right side of the center line is the view from arrow A in Figure 1, and the left side is the view from arrow B, and Figure 3 is the view from arrow B. 181. C arrow view in Figure 181. FIG. 4 is a view taken along arrow D in FIG. 1-...Carrier 2...Disc 6...Inner pad 9...Caliper 11...Piston
13...Cylinder side member 14...Claw side member
14a...Disk bus part 14b...Claw part
15...Threaded hole 17...Tie bolt (bolt) 18.19...Thick wall part P...-Inflection point Patent applicant Tokico Co., Ltd. Figure 3 Figure 4

Claims (2)

[Claims] (1) The caliper, which is supported in a floating state on the non-rotating part of the vehicle body, is connected to the cylinder side member that supports the piston that presses the inner pad against the disc, the disc pass part that straddles the disc, and the claw part that engages with the atau pad. In the disc brake, the disc brake is divided into two members, a claw side member and a claw side member, and each of the members is fixed by a bolt that passes through the cylinder side member from the axial direction of the disc and is screwed into the disc path part. A built-up portion is provided on the outside of the joint between the member and the claw-side member, and the bolt is inserted into the claw-side member at a point where the outer surface of the built-up portion of the claw-side member intersects with the outer surface of the disk path portion. A disc brake characterized by being screwed together to a position near the pawl. (2) The disc brake according to claim 1, wherein the shaft of the bolt is located inward from the center position in the thickness direction of the disc path portion of the claw side member.