JP2002235779A - Disc brake with parking mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a cost by facilitating an operation for connecting and fixing the base end of a camshaft 13 forming a parking mechanism to the base end of a lever 20. SOLUTION: The base end of the camshaft 13 is provided with a locking flange 21 and a camshaft-side engaging part 22. The base end of the lever 20 is provided with a locking hole 25 having a pair of tongue pieces 27, 27 at its inner periphery. The locking flange 21 is passed through a space between these tongue pieces 27, 27 with the space between the tongue pieces 27, 27 being enlarged, and the camshaft-side engaging part 22 is pressed into the space between the tongue pieces 27, 27. This eliminates the need for a nut, serves the above-described purpose and allows weight reduction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A disc brake with a parking mechanism according to the present invention is used for braking an automobile. In particular, the present invention simplifies the structure of a disc brake provided with a parking brake mechanism for keeping a vehicle stopped, thereby realizing a low-cost structure.

[0002]

2. Description of the Related Art Various types of disc brakes for braking an automobile have been known. Various disc brakes with a parking mechanism have been proposed and actually used as described in Japanese Utility Model Publication No. 2-20509, for example. The disc brake with a parking mechanism described in this publication uses a piston for a service brake (a brake for decelerating or stopping a running automobile) to operate the parking brake. That is, the piston that protrudes due to the feeding of the pressure oil into the cylinder during the service brake is mechanically protruded by the parking mechanism provided with the lever, the camshaft, and the rod regardless of the state of the pressure oil being fed during the parking brake. , The parking brake is actuated.

[0003] In the case of the disc brake with a parking mechanism described in Japanese Utility Model Publication No. 2-20509, a nut is used to connect and fix the base end of the lever to one end of a cam shaft constituting the parking mechanism. Was. That is, a nut is screwed into this male screw portion and further tightened in a state in which the base end portion of the lever is externally fitted and fixed to a male screw portion having a smaller diameter than the other portion formed at the end portion of the camshaft. The lever was connected and fixed to one end of the camshaft. When the parking mechanism operates, the camshaft is rotated via the lever, the displacement of the cam surface of the camshaft is transmitted to the piston via the rod, and a pair of pads is pressed against both side surfaces of the rotor. .

[0004]

When the lever and the camshaft are connected by a nut, a nut is required, and an operation of forming a male screw portion at one end of the camshaft is required. For this reason, not only the number of components of the parking mechanism increases, but also the number of man-hours required for processing the components increases, and further, the nuts are screwed /
Since the tightening work is troublesome and the assembling work is also troublesome, the cost increases. Further, the weight increases due to the use of the nut.
Since the disc brake has a so-called unsprung load, even a slight increase in weight is unfavorable because it has a bad effect on the performance of the vehicle mainly in ride comfort. The disc brake with a parking mechanism according to the present invention was invented in view of such circumstances.

[0005]

A disk brake with a parking mechanism according to the present invention is similar to a disk brake with a parking mechanism described in Japanese Utility Model Laid-Open Publication No. 2-20509 described above, which is conventionally known. , A pair of pads, a caliper, a piston, a camshaft, a rod, and a lever. The support is supported on the vehicle body side across the rotor that rotates with the wheels. or,
The pads are arranged on both sides of the rotor. The caliper is supported by and attached to the support. The piston is fitted in the cylinder of the caliper. The cam shaft is rotatably supported by the caliper. The above rod is
The piston is provided between a cam surface formed on the cam shaft and the piston, and a displacement of the cam surface is transmitted to the piston. Further, the lever has a base end coupled and fixed to a portion protruding outside the caliper at one end of the camshaft. The rotor is held between the pair of pads as the piston is pushed out.

In particular, in the disc brake with a parking mechanism according to the present invention, the locking flange, the cam shaft side engaging portion,
It has a locking hole and a tongue. The locking flange is formed at one end of the camshaft. The camshaft-side engaging portion is formed near the center of one end of the camshaft and adjacent to the locking flange, and has a non-circular cross-sectional shape. Further, the locking hole has a shape for preventing rotation of the cam shaft with respect to the lever based on engagement with the cam shaft side engaging portion in a state where one end of the cam shaft is inserted. , Formed at the base end of the lever. Further, the tongue piece is formed on the periphery of the locking hole. Then, based on the engagement between the leading edge of the tongue and the locking flange, the end of the camshaft from the locking hole is prevented from coming off.

[0007]

In the case of the disc brake with a parking mechanism according to the present invention constructed as described above, the tongue is elastically deformed while passing through the locking flange provided at one end of the cam shaft through the leading edge of the tongue. By doing so, the one end of the cam shaft and the base end of the lever can be connected and fixed. Therefore, the connecting portion between the one end of the camshaft and the base end of the lever can be configured easily, at low cost, and lightweight.

[0008]

1 to 8 show an embodiment of the present invention. The disc brake with a parking mechanism of the present embodiment is of a floating caliper type that displaces a caliper 2 with respect to a rotor 1 during braking. In this floating caliper type disc brake, a support 3 provided adjacent to the rotor 1 which rotates together with wheels (not shown) is fixed to a vehicle body (not shown). In the case of this example, the support 3 is the rotor 1
And supports the caliper 2 so that the rotor 1 can be displaced in the axial direction.

In this embodiment, the pad 3a on the inner side (close to the center in the width direction of the vehicle, right side in FIG. 1) and the outer side (outward in the width direction of the vehicle, FIG. The pad 4b (on the left side) is slidably engaged with the rotor 1 in the axial direction (the left-right direction in FIG. 1). The inner side pad 4a and the outer side pad 4b are connected to the back plate 6 respectively.
The linings 7a and 7b are additionally provided on the surface of one of the surfaces a and 6b facing the side surface of the rotor 1. At the center of the other surface of the back plate 6a constituting the inner pad 4a,
The distal end surface of a piston 11 built in a cylinder portion 10 provided at an intermediate portion of the caliper 2 is abutted. On the other hand, the inner surface of the caliper claw 5 formed at the outer end of the caliper 2 is in contact with the other surface of the back plate 6b of the pad 4b on the outer side. The outer pad 4b is supported by the caliper claw 5.

Further, a bearing portion 12 is provided at an inner end of the caliper 2 in a direction orthogonal to the cylinder portion 10. A cam shaft 13 is rotatably supported in the bearing portion 12 by a radial needle bearing 14 (see FIGS. 1 and 2). The cam shaft 13 has a cam surface 15 at a portion near the tip of the intermediate portion (lower portion in FIGS. 1 and 2). The cam surface 15 has a shape in which the distance from the center axis gradually changes in the circumferential direction. A rod 16 is provided between the cam surface 15 and the piston 11 so that the cam surface 15
Is freely transmitted to the piston 11.

In the illustrated example, the linings 7a, 7b
An automatic clearance adjusting device 17 for automatically adjusting the position of the piston 11 at the time of non-braking in accordance with the wear of the vehicle is incorporated. By the action of the automatic gap adjusting device 17,
When the brake is not applied, the linings 7a and 7b and the rotor 1
The gap existing between the linings 7a and 7b is kept constant so that the amount of depression of the brake pedal during braking does not increase irrespective of the progress of wear of the linings 7a and 7b. A non-cylindrical portion 18 having an oval cross section formed at an intermediate portion of the rod 16 is provided in the cylinder portion 10.
It is fitted into a central hole of the same shape formed in the axial movement restricting plate 19 (see FIGS. 1 and 2) of the rod 16 provided between the shaft 16 and the bearing portion 12.
When a low hydraulic pressure is applied in a state where the distance between each of the linings 7a and 7b and the rotor 1 is large, the O-ring 30 mounted on the rod 16 comes out to the hydraulic chamber side of the cylinder portion 10. Has been prevented. Further, a part of the radial needle bearing 14 through which a two-plane width portion (a section having an oval cross section) of the rod 16 is inserted is discontinuous. Further, the rod 16 has its two-plane width portion engaged with a portion of the camshaft 13 where the cam surface 15 is formed, and is prevented from rotating. The basic structure and operation of the automatic gap adjusting device 17 are the same as those described in
As described in Japanese Patent Publication No. -20509, etc., since it is well known from the past, detailed description is omitted.

A base end of the cam shaft 13 (one end described in the claims) protrudes out of the caliper 2. The base end of the lever 20 is fixedly connected to the base end of the cam shaft 13. A locking flange 21 is provided at the base end of the camshaft 13, and a camshaft-side engaging portion 2
2 are formed adjacent to each other. The locking flange portion 21 has a substantially rectangular outward flange shape, and the camshaft-side engaging portion 22 has a rectangular cross section and two pairs of parallel flat portions 23 and 24. In other words, the long side portions of the cross-sectional shape of the camshaft side engaging portion 22 are a pair of flat portions 23, 23 parallel to each other, and the short side is also a pair of flat portions 24, 24 parallel to each other. .

On the other hand, a locking hole 25 for inserting the base end of the cam shaft 13 is formed in the base end of the lever 20. Further, a pair of tongue pieces 27, 27 are provided on both sides of the periphery of the locking hole 25. These tongue pieces 27, 27
Is formed by bending and raising a pair of parallel cuts 26, 26 corresponding to the interval between the pair of plane portions 24, 24 on the short side. That is, a punched hole is formed at the center of the portion between the cuts 26, 26, and the portions surrounded by the punched hole and the cuts 26, 26 are bent and raised in the same direction, and the tongues are formed. Pieces 27, 27. These distal edge 28 of each tongue 27, 27 are parallel to each other, the distance D ₂₈ in the free state is larger than the planar portion 23, 23 between the spacing D ₂₃ of the pair of the long side ( D ₂₈ > D ₂₃ ). The space between the surfaces perpendicular to the tongue pieces 27 at the inner peripheral edge of the locking hole 25 is slightly smaller than the space between the pair of flat portions 24 on the short side. .

The lever 2 is attached to the base end of the cam shaft 13 as described above.
To connect and fix the base end of the cam shaft 13, the base end of the cam shaft 13 is pushed into the locking hole 25 formed in the base end of the lever 20. The pushing operation is performed by the tongue pieces 27, 27
From the opposite side (the lower side of FIGS. 1, 2, 7, and 8). With this pushing operation, the tongue pieces 27, 27
However, it is deformed in a direction to widen the interval between the respective distal end edges 28, 28, and allows passage of the locking flange 21 formed at the base end of the cam shaft 13. After the locking flange 21 has passed, the leading edges 28, 28 of the tongue pieces 27, 27
Are the flat portions 23, 2 on the long side of the cam shaft side engaging portion 22.
3 or a close opposition. In this state, the flat portions 24, 24 on the short side of the camshaft-side engaging portion 22 are provided between two surfaces orthogonal to the tongue pieces 27, 27 at the inner peripheral edge of the locking hole 25. Press-fit.

As a result, the relative rotation between the cam shaft side engaging portion 22 and the locking hole 25 is prevented. Further, based on the engagement between the leading edges 28, 28 of the tongue pieces 27, 27 and the locking flange 21, the camshaft 13 from the locking hole 25 is formed.
Of the base end portion is prevented. In this way, the operation of connecting and fixing the base end of the cam shaft 13 to the base end of the lever 20 is as follows.
This can be performed by pushing the base end of the cam shaft 13 into the locking hole 25, so that the assembling work of the parking mechanism is facilitated. Further, the weight of the parking mechanism can be reduced because the nut is not used. A boot 29 made of an elastic material such as rubber or the like is stretched between the intermediate portion of the cam shaft 13 near the base end and the opening of the bearing portion 12.
Therefore, no foreign matter enters the bearing portion 12.

When braking is performed during running of the vehicle (during service braking) by the disk brake with a parking mechanism of the present invention configured as described above, pressurized oil is fed into the cylinder portion 10 and the piston 11 The pad 4a on the inner side is attached to the inner surface of the rotor 1,
Press from right to left in FIG. Then, as a reaction of this pressing force, the caliper 2 is displaced rightward in FIG.
The caliper claw 5 presses the outer pad 4b against the outer surface of the rotor 1. As a result, the rotor 1 is strongly clamped from both inner and outer side surfaces, and braking is performed.

When the parking brake is actuated, the camshaft 13 is rotated via the lever 20 by a cable pulled by operation of a parking lever (including a foot-operated pedal) provided in the driver's seat. . As a result, the cam surface 15 provided on the cam shaft 13 is
6 is pushed to the left in FIG. 1, and the inner pad 4 a on the inner side surface of the rotor 1 is
From right to left. As a result, as in the case of the service brake described above, the rotor 1 is strongly clamped from both the inner and outer side surfaces, and the parking brake is activated.

[0018]

Since the present invention is constructed and operates as described above, it is possible to reduce the cost of the disc brake with the parking mechanism and to improve the performance of the automobile by reducing the weight.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of an embodiment of the present invention.

FIG. 2 is an enlarged view of a part A of FIG.

FIG. 3 is a view of the cam shaft taken out and viewed from the same direction as FIG. 1;

FIG. 4 is a view as seen from above in FIG. 3;

FIG. 5 is a view showing the lever taken out from above in FIG. 1;

FIG. 6 is a view as viewed from below in FIG. 5;

FIG. 7 is a sectional view taken along the line BB of FIG. 5;

FIG. 8 is a view similar to FIG. 7, showing the state combined with a cam shaft.

[Explanation of symbols]

 Reference Signs List 1 rotor 2 caliper 3 support 4a, 4b pad 5 caliper claw 6a, 6b back plate 7a, 7b lining 8 locking protrusion 9 locking recess 10 cylinder portion 11 piston 12 bearing portion 13 cam shaft 14 radial needle bearing 15 cam surface 16 Rod 17 Automatic gap adjusting device 18 Non-cylindrical portion 19 Movement restricting plate 20 Lever 21 Locking flange portion 22 Cam shaft side engaging portion 23 Flat portion 24 Flat portion 25 Lock hole 26 Cut 27 Tongue piece 28 Tip edge 29 Boot

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3J058 AA43 AA48 AA53 AA63 AA69 AA73 AA77 AA79 AA87 BA52 BA64 BA68 CC08 CC52 DD05 FA07 GA92

Claims (1)

[Claims] 1. A support supported on a vehicle body side adjacent to a rotor rotating with wheels, a pair of pads disposed on both sides of the rotor, a caliper supported by the support, and a cylinder of the caliper. A piston fitted in the portion, a cam shaft rotatably supported by the caliper, and a rod provided between the cam surface formed on the cam shaft and the piston to transmit displacement of the cam surface to the piston A parking mechanism for clamping the rotor by the pair of pads as the piston is pushed out, and a lever having a base end coupled and fixed to a portion of the cam shaft protruding outside the caliper at one end of the cam shaft. In the disc brake, a locking flange formed at one end of the camshaft, and a cross-sectional shape formed adjacent to the locking flange at a portion near the center of one end of the camshaft. A non-circular camshaft side engaging portion,
An engagement portion formed at a base end portion of the lever having a shape for preventing rotation of the cam shaft with respect to the lever based on engagement with the engagement portion on the cam shaft side with one end of the cam shaft inserted. A locking hole, and a tongue formed at a peripheral portion of the locking hole. The camshaft from the locking hole is formed based on the engagement between the leading edge of the tongue and the locking flange. A disc brake with a parking mechanism, characterized in that one end is prevented from coming off.