JP2008185059A - Disc brake device - Google Patents

Abstract

An object of the present invention is to provide a disc brake device capable of ensuring appropriate braking response from a reduced speed region to a high deceleration region and improving brake feeling in the reduced speed region.
When braking in a reduced speed region where the brake fluid pressure is low, the brake fluid absorbing mechanism 9 absorbs the brake fluid supplied to the caliper cylinder, so that the amount of brake fluid consumed increases. As a result, the brake pedal depression stroke becomes longer according to the increase in the amount of brake fluid consumption, and the brake pedal feeling in the reduced speed region is improved. On the other hand, when braking in a high deceleration region where the brake fluid pressure is high, the brake fluid absorbing mechanism 9 does not absorb the brake fluid, so that the amount of brake fluid consumed is reduced accordingly. As a result, the depression stroke of the brake pedal is reduced, and an appropriate braking response is ensured when braking in a high deceleration region.
[Selection] Figure 4

Description

  The present invention relates to a disc brake device provided as a braking device in a vehicle.

  A disc brake device mounted on a vehicle is generally configured to press a brake pad disposed opposite to both sides of the disc rotor against both sides of the disc rotor by a caliper piston fitted into the caliper cylinder. The braking force changes according to the brake fluid pressure supplied to the caliper cylinder.

  In this type of disc brake device, a seal member is mounted on the inner periphery of the caliper cylinder so as to maintain a liquid-tight state with the caliper piston. This seal member has a function of elastically deforming when the caliper piston advances from the caliper cylinder during braking, and pulling back the caliper piston into the caliper cylinder by elastic restoring force during non-braking.

  Here, the brake fluid supplied to the caliper cylinder at the time of braking is consumed according to the elastic deformation amount of the seal member when the caliper piston advances from the caliper cylinder. The amount of brake fluid consumed influences the depression stroke of the brake pedal, and if the amount of consumption fluid is large, the depression stroke of the brake pedal becomes longer and the braking response is reduced.

Therefore, conventionally, a disc brake device has been proposed in which the shape of the seal member mounted on the inner periphery of the caliper cylinder is improved to reduce the amount of brake fluid consumed during braking and improve the braking response. (See, for example, Patent Document 1).
Japanese Patent Laid-Open No. 11-270600

  By the way, in a disc brake device in which the amount of brake fluid consumed during braking is simply reduced, the braking responsiveness becomes excessively sensitive during braking in a reduced speed region where the brake fluid pressure supplied to the caliper cylinder is low. Feeling cannot be obtained.

  Accordingly, it is an object of the present invention to provide a disc brake device that can ensure appropriate braking response from a reduced speed region to a high deceleration region and can improve brake feeling in the reduced speed region. .

  The disc brake device according to the present invention is a disc brake device that obtains a braking force by pressing a brake pad against a disc rotor by a caliper piston according to a brake hydraulic pressure supplied to the caliper cylinder, and a brake supplied to the caliper cylinder. A brake fluid absorbing mechanism for absorbing the fluid in a reduced speed region where the brake fluid pressure is low is provided.

  In the disc brake device according to the present invention, the brake fluid absorption mechanism absorbs the brake fluid supplied to the caliper cylinder during braking in the reduced speed region where the brake fluid pressure is low, so the amount of brake fluid consumption increases. . As a result, the depression stroke of the brake pedal becomes longer according to the increase in the amount of brake fluid consumption, and the brake feeling in the reduced speed region is improved.

  On the other hand, when braking in a high deceleration region where the brake fluid pressure is high, the brake fluid absorbing mechanism does not absorb the brake fluid, so that the amount of brake fluid consumed is reduced accordingly. As a result, the depression stroke of the brake pedal is reduced, and an appropriate braking response is ensured when braking in a high deceleration region.

  Here, the brake fluid absorbing mechanism in the disc brake device of the present invention has a pad pressing member that is pressed against the brake pad by the caliper piston in the reduced speed region, and the caliper piston moves relative to the pad pressing member in the reduced speed region. Thus, the brake fluid supplied to the caliper cylinder can be absorbed. In this case, the brake fluid absorption amount (consumed fluid amount) accompanying the relative movement of the caliper piston is large, so that the brake feeling is improved from the beginning of the braking operation in the reduced speed region.

  Further, the brake fluid absorbing mechanism may have a structure having a first elastic member that transmits a pressing force from the caliper piston to the pad pressing member. In this case, if the spring characteristic of the first elastic member is a non-linear spring characteristic, the relative movement of the caliper piston is reduced in accordance with an increase in the brake fluid pressure acting on the caliper piston, and the amount of brake fluid absorbed (consumed fluid amount). Can be continuously reduced, and the brake feeling in the reduced speed region can be further improved.

  Furthermore, the brake fluid absorbing mechanism can have a structure having a second elastic member that biases the pad pressing member toward the first elastic member. In this case, since the pad pressing member is prevented from rattling with respect to the caliper piston, the pressing force of the caliper piston is immediately transmitted to the pad pressing member via the first elastic member, and braking in the reduced speed region is performed. Brake feeling is improved from the beginning of operation.

  Here, it is preferable that the spring constant of the second elastic member is set to be smaller than the spring constant of the first elastic member because the nonlinear spring characteristic of the first elastic member is effectively exhibited.

  In the disc brake device of the present invention, the pad pressing member has a pressure receiving portion that receives the brake fluid pressure through the pressure receiving portion of the caliper piston, and the pressure receiving area of the pad pressing member is set smaller than the pressure receiving area of the caliper piston. If so, the caliper piston follows the rotor surface of the disk rotor together with the pad pressing member, and both balance the pressure. For this reason, it becomes possible to suppress the vibration caused by the surface runout or thickness difference of the disk rotor during braking in the reduced speed region.

  Here, a second seal member having a sliding resistance smaller than that of the first seal member provided between the caliper cylinder and the caliper piston is provided at a fitting portion between the pressure receiving portion of the caliper piston and the pressure receiving portion of the pad pressing member. In this case, only the pad pressing member is pressed toward the brake pad at the initial stage of braking in the reduced speed region to absorb the brake fluid. For this reason, the amount of absorbed brake fluid (consumed fluid amount) at the time of braking in the reduced speed region is reduced, and the brake feeling is improved.

  According to the disc brake device of the present invention, the brake fluid absorbing mechanism absorbs the brake fluid when braking in the reduced speed region, and the brake fluid absorbing mechanism absorbs the brake fluid when braking in the high deceleration region. Therefore, appropriate braking response can be ensured from the reduced speed region to the high deceleration region, and the brake feeling in the reduced speed region can be improved.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode of a disc brake device according to the present invention will be described below with reference to the drawings. In the drawings to be referred to, FIG. 1 is a perspective view showing an appearance of a disc brake device according to an embodiment of the present invention, and FIG. 2 is a partial cross-sectional view schematically showing a cross-sectional structure of a caliper of the disc brake device shown in FIG. FIG. 3 is an enlarged cross-sectional view of the caliper piston shown in FIG.

  A disc brake device according to an embodiment is provided as a braking device in a vehicle (not shown). For example, as shown in FIG. 1, this disc brake device straddles the outer periphery of the disc rotor 2 supported by a disc rotor 2 fixed to an axle hub 1 and rotated integrally with a suspension part of a vehicle body (not shown). And a floating caliper 5 mounted on the mounting 3 through a pair of slide pins 4 and 4 so as to be slidable in parallel with the rotational axis of the disk rotor 2. ing.

  As shown in FIG. 2, the caliper 5 having a bridge structure arranged across the outer periphery of the disk rotor 2 includes a caliper cylinder 5A facing the inner rotor surface 2A formed on the outer periphery of the disk rotor 2, and an outer rotor surface. It has a pair of claw portions 5B and 5B (see FIG. 1) facing 2B, and a cup-shaped caliper piston 6 is fitted in the caliper cylinder 5A.

  When the brake fluid pressure supplied into the caliper cylinder 5A via the brake piping of the vehicle (not shown) acts on the pressure receiving surface 6B on the outer surface of the pressure receiving portion 6A, the caliper piston 6 is parallel to the rotating shaft of the disc rotor 2. It is configured to advance from 5A.

  A seal member 5C is mounted on the inner periphery of the caliper cylinder 5A to hold the caliper piston 6 with the outer peripheral surface in a liquid-tight state. The seal member 5C has a function of elastically deforming when the caliper piston 6 advances from the caliper cylinder 5A during braking, and pulling back the caliper piston 6 into the caliper cylinder 5A by elastic restoring force during non-braking.

  A brake pad 7 is disposed between the opening end of the caliper piston 6 and the inner rotor surface 2 </ b> A of the disc rotor 2. A similar brake pad 7 is also disposed between the claw portions 5B and 5B of the caliper 5 and the outer rotor surface 2B of the disc rotor 2.

  The brake pads 7 and 7 have a structure in which the pad members 7B and 7B are joined to the back metal 7A and 7A. In one brake pad 7, the back metal 7A faces the caliper piston 6 and the pad member 7B is the disc rotor 2. It faces the inner rotor surface 2A. In the other brake pad 7, the back metal 7 </ b> A faces the claws 5 </ b> B and 5 </ b> B of the caliper 5, and the pad member 7 </ b> B faces the outer rotor surface 2 </ b> B of the disc rotor 2.

  A pad shim 8 facing the caliper piston 6 is attached to the back metal 6A of one brake pad 7 in order to suppress so-called brake squeal noise by suppressing high-frequency vibration generated by the brake pads 7, 7 during braking. A pad shim 8 facing the claws 5B, 5B of the caliper 5 is attached to the back metal 7A of the other brake pad 7.

  Here, as shown in FIG. 3, a brake fluid absorbing mechanism 9 is incorporated in the cup-shaped caliper piston 6. The brake fluid absorbing mechanism 9 is a mechanism for absorbing the brake fluid supplied into the caliper cylinder 5A shown in FIG. 2 in a reduced speed region where the brake fluid pressure is low, and the caliper piston 6 is relatively moved in the advancing and retracting direction. A plunger 9A as a possible pad pressing member, a first disc spring 9B as a first elastic member for transmitting the pressing force of the caliper piston 6 to the plunger 9A, and a plunger 9A biased toward the first disc spring 9B side The second disc spring 9C as a second elastic member is mainly configured.

  The plunger 9A is screwed into the inner peripheral surface of the caliper piston 6 through a Teflon ring (Teflon is a registered trademark) TR so as to be slidable, and an open end of the caliper piston 6. Plunger portion 9A2 is integrally formed on the inner peripheral surface of adjustment ring 9D with a tip portion slidably fitted through a Teflon ring TR having a small sliding resistance.

  The distal end surface 9A3 of the plunger portion 9A2 is formed in a curved convex surface, and the distal end surface 9A3 projects from the opening side end surface 6C of the caliper piston 6 by a predetermined amount in the initial state. In this initial state, between the rear end surface 9A4 of the plunger portion 9A2 and the pressure receiving portion inner surface 6D of the caliper piston 6, the tip end surface 9A3 of the plunger portion 9A2 moves with a margin to the position of the opening side end surface 6C of the caliper piston 6. A gap that can be made is secured.

  The first disc spring 9B is disposed between the pressure receiving portion 6A of the caliper piston 6 and the piston portion 9A1 of the plunger 9A. The large diameter portion abuts against the pressure receiving portion inner surface 6D, and the small diameter portion is the piston portion 9A1. It is in contact with one side. On the other hand, the second disc spring 9C is disposed between the adjustment ring 9D and the piston portion 9A1 of the plunger 9A, the large diameter portion abuts against the inner end surface of the adjustment ring 9D, and the small diameter portion is the piston portion 9A1. It is in contact with the other side.

  Here, when the brake fluid pressure acts on the pressure receiving surface 6B of the caliper piston 6 and the tip surface 9A3 of the plunger 9A contacts the brake pad 7 (see FIG. 2), the first disc spring 9B receives the pressure of the caliper piston 6. The caliper piston 6 is pushed and bent by the inner surface 6D, and the caliper piston 6 is moved relative to the plunger 9A toward the brake pad 7 side.

  The first disc spring 9B has a non-linear spring characteristic that continuously decreases the relative movement amount of the caliper piston 6 with respect to the plunger 9A in accordance with an increase in the brake fluid pressure acting on the pressure receiving surface 6B of the caliper piston 6. . The first disc spring 9B is configured such that the deceleration of the boundary between the vehicle reduction speed region and the high deceleration region (not shown) is 0.4 G, for example, and the corresponding brake fluid pressure of about 4 Mpa is received by the caliper piston 6. When acting on the surface 6B, the spring constant is set so that the opening side end surface 6C of the caliper piston 6 bends to a position that coincides with the tip end surface 9A3 of the plunger 9A.

  On the other hand, the second disc spring 9C also has a non-linear spring characteristic. The spring constant of the second disc spring 9C is such that the first disc spring 9B can effectively exhibit the non-linear spring characteristic. Is set smaller than the spring constant. That is, the second disc spring 9C has a softer characteristic than the first disc spring 9B. The spring constants of the first disc spring 9B and the second disc spring 9C are adjusted according to the screwing amount of the adjusting ring 9D screwed into the opening end of the caliper piston 6.

  In the disc brake device of the embodiment configured as described above, when a braking operation is performed by a brake pedal of a vehicle (not shown), the brake hydraulic pressure corresponding to the depression operation of the brake pedal is shown in FIG. The brake fluid pressure is supplied to 5A and acts on the pressure receiving surface 6B of the caliper piston 6.

  Here, when the brake fluid pressure acting on the pressure receiving surface 6B of the caliper piston 6 is 4 Mpa or less corresponding to the vehicle deceleration 0.4G, that is, in the vehicle reduction speed region, as shown in FIG. 6, the pressing force is transmitted to the plunger 9A via the first disc spring 9B, and the plunger 9A presses the back metal 7A of one brake pad 7 at the tip end surface 9A3 of the plunger portion 9A2.

  On the other hand, when the brake hydraulic pressure acting on the pressure receiving surface 6B of the caliper piston 6 exceeds 4 Mpa corresponding to the vehicle deceleration 0.4G, that is, in the high deceleration region of the vehicle, as shown in FIG. Since the first disc spring 9B bends to a position where the opening end face 6C coincides with the tip end face 9A3 of the plunger 9A, the opening end face 6C of the caliper piston 6 presses the back metal 7A of one brake pad 7.

  Then, the claw portions 5B and 5B of the caliper 5 shown in FIG. 2 press the backing metal 7A of the other brake pad 7 by the reaction force of the pressing force acting on the backing metal 7A of the one brake pad 7. The pad members 7B and 7B of the brake pads 7 and 7 are brought into frictional contact with the inner rotor surface 2A and the outer rotor surface 2B of the disc rotor 2, and thus a braking force is obtained.

  Here, in the reduced speed region of the vehicle until the brake fluid pressure acting on the pressure receiving surface 6B of the caliper piston 6 reaches 4 Mpa corresponding to the vehicle deceleration 0.4G, the first brake fluid absorbing mechanism 9 is configured. The disc spring 9B is bent to move the caliper piston 6 relative to the plunger 9A toward the brake pad 7 side. As a result, the brake fluid supplied into the caliper cylinder 5A shown in FIG. 2 is absorbed according to the relative movement amount of the caliper piston 6, and the brake fluid absorption amount (consumed fluid amount) is greatly increased. Accordingly, the depression stroke of a brake pedal (not shown) becomes longer according to the increase in the amount of absorbed brake fluid (consumed fluid amount), and the brake feeling is improved from the beginning of the braking operation in the reduced speed region of the vehicle.

  In addition, in the disc brake device according to the embodiment, the first disc spring 9B constituting the brake fluid absorbing mechanism 9 has a non-linear spring characteristic, which increases the brake fluid pressure acting on the pressure receiving surface 6B of the caliper piston 6. Accordingly, since the relative movement amount of the caliper piston 6 with respect to the plunger 9A is continuously reduced, the brake feeling in the reduced speed region of the vehicle is further improved.

  Further, since the brake fluid absorbing mechanism 9 has a structure having the second disc spring 9C that urges the plunger 9A toward the first disc spring 9B, the rattling of the plunger 9A with respect to the caliper piston 6 is prevented. As a result, the pressing force of the caliper piston 6 is immediately transmitted to the plunger 9A via the first disc spring 9B, and the brake feeling is improved from the beginning of the braking operation in the reduced speed region of the vehicle.

  Further, since the spring constant of the second disc spring 9C constituting the brake fluid absorbing mechanism 9 is set smaller than the spring constant of the first disc spring 9B, the non-linear spring characteristic of the first disc spring 9B is effectively exhibited. The relative movement amount of the caliper piston 6 with respect to the plunger 9A continuously decreases as the brake fluid pressure increases.

  As a result, compared with the characteristic of the conventional example shown by the dotted line in FIG. 6, in the disc brake device of one embodiment, as shown by the solid line in FIG. The (consumed fluid amount) increases rapidly, and the brake fluid absorption amount (consumed fluid amount) gradually decreases in a high deceleration region of a vehicle having a high brake fluid pressure.

  On the other hand, in the high deceleration region of the vehicle where the brake hydraulic pressure acting on the pressure receiving surface 6B of the caliper piston 6 exceeds 4 Mpa corresponding to the vehicle deceleration 0.4G, as shown in FIG. Since the end face 6C is in contact with the back metal 7A of one brake pad 7, the brake fluid absorbing mechanism 9 does not absorb the brake fluid supplied into the caliper cylinder 5A shown in FIG. As a result, the amount of brake fluid absorbed (consumed fluid amount) is reduced, the brake pedal depression stroke is reduced, and appropriate braking response is ensured in a high deceleration region of the vehicle.

  Therefore, according to the disc brake device of one embodiment, the brake fluid pressure supplied to the caliper cylinder 5A is appropriate from a reduced speed region of 4 Mpa or less corresponding to, for example, a vehicle deceleration of 0.4 G to a high deceleration region of 4 Mpa or more. Thus, it is possible to ensure a good braking response, and in particular, it is possible to improve the brake feeling during braking in the reduced speed region.

  The disc brake device according to the present invention is not limited to the above-described embodiment, and the structure of the main part thereof can be changed as appropriate. For example, the brake fluid absorbing mechanism 9 shown in FIG. 3 can be changed to the structure shown in FIG.

  In the brake fluid absorbing mechanism 9 shown in FIG. 7, the second disc spring (second elastic member) 9C shown in FIG. 3 is a linear spring smaller than the spring constant of the first disc spring (first elastic member) 9B. The coil spring 9E having a constant is changed. Further, the piston portion 9A1 constituting the plunger (pad pressing member) 9A is changed to a small-diameter spring receiving flange portion 9A5.

  Here, the rear end portion of the plunger portion 9A2 constituting the plunger (pad pressing member) 9A passes through the fitting hole 6E formed in the pressure receiving portion 6A of the caliper piston 6, and the rear end surface of the plunger portion 9A2 9A4 is a pressure receiving surface that receives the brake fluid pressure. The pressure receiving area of the rear end face 9A4 is set smaller than the pressure receiving area of the pressure receiving surface 6B of the caliper piston 6.

  In addition, a plunger seal (second seal member) 9F that applies sliding resistance to the peripheral surface of the rear end portion of the plunger portion 9A2 is mounted in the fitting hole 6E of the caliper piston 6. On the other hand, a caliper piston seal (first seal member) 9G that increases sliding resistance with the inner peripheral surface of the caliper cylinder 5A is mounted on the outer periphery of the caliper piston 6 in the vicinity of the pressure receiving portion 6A. Here, the plunger seal (second seal member) 9F has a cup-shaped cross-sectional shape having a sliding resistance smaller than that of the caliper piston seal (first seal member) 9G.

  In the disc brake device provided with the brake fluid absorbing mechanism 9 having the structure shown in FIG. 7, the second coil spring 9E having a linear spring constant smaller than the spring constant of the first disc spring 9B as the first elastic member is used. Therefore, the non-linear spring characteristic of the first disc spring 9B that bends in the reduced speed region of the vehicle is more effectively exhibited.

  Further, at the time of braking in which the brake fluid pressure is supplied into the caliper cylinder 5A, the rear end surface 9A4 of the plunger portion 9A2 of the plunger (pad pressing member) 9A receives the brake fluid pressure with a small pressure receiving area, and simultaneously the pressure receiving surface of the caliper piston 6 6B receives a brake fluid pressure in a large pressure receiving area. For this reason, the tip end surface 9A3 of the plunger portion 9A2 and the opening side end surface 6C of the caliper piston 6 follow the inner rotor surface 2A of the disc rotor 2 via one brake pad 7, and both are in pressure balance. . As a result, during braking in the reduced speed region of the vehicle, vibration due to surface runout and thickness difference of the disk rotor 2 is suppressed.

  Further, when the brake fluid pressure acts on the rear end surface 9A4 of the plunger portion 9A2 and the pressure receiving surface 6B of the caliper piston 6, the plunger seal (in comparison with the sliding resistance of the caliper piston 6 by the caliper piston seal (first seal member) 9G) The plunger portion 9A2, which has a small sliding resistance by the second seal member 9F, moves toward the one brake pad 7 prior to the caliper piston 6 at the initial stage of braking in the reduced speed region of the vehicle. Since the brake fluid is absorbed by the movement of the plunger portion 9A2 and the absorbed amount (consumed fluid amount) is reduced, the initial brake feeling during braking in the reduced speed region of the vehicle is further improved.

  In addition, in order to reliably move the plunger portion 9A2 relative to the caliper piston 6 at the initial stage of braking in the reduced speed region of the vehicle, the caliper piston 6 includes a caliper piston seal (first seal member) 9G. Other sliding resistance applying means may be provided.

1 is a perspective view showing an external appearance of a disc brake device according to an embodiment of the present invention. It is a fragmentary sectional view which shows typically the cross-sectional structure of the caliper of the disc brake apparatus shown in FIG. It is an expanded sectional view which shows the internal structure of the caliper piston shown in FIG. FIG. 4 is an enlarged cross-sectional view showing an operation in a reduction speed region of the brake fluid absorbing mechanism shown in FIG. 3. FIG. 4 is an enlarged cross-sectional view showing the operation of the brake fluid absorbing mechanism shown in FIG. 3 in a high deceleration region. FIG. 4 is a characteristic graph showing the relationship between the brake fluid pressure that changes due to the action of the brake fluid absorption mechanism shown in FIG. 3 and the amount of rake fluid consumed. FIG. 4 is an enlarged cross-sectional view corresponding to FIG. 3 showing a modification of the brake fluid absorbing mechanism shown in FIG. 3.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... Disc rotor, 2A ... Inner rotor surface, 2B ... Outer rotor surface, 5 ... Caliper, 5A ... Caliper cylinder, 5B ... Claw part, 5C ... Seal member, 6 ... Caliper piston, 6A ... Pressure receiving part, 6B ... Pressure receiving surface , 6C ... Opening side end face, 6D ... Pressure receiving part inner surface, 6E ... Fitting hole, 7 ... Brake pad, 7A ... Back metal, 7B ... Pad member, 9 ... Brake fluid absorption mechanism, 9A ... Plunger (pad pressing member), 9A1 ... piston part, 9A2 ... plunger part, 9A3 ... tip end face, 9A4 ... rear end face, 9A5 ... spring receiving flange part, 9B ... first disc spring (first elastic member), 9C ... second disc spring (second Elastic member), 9D ... Adjustment ring, 9E ... Coil spring, 9F ... Plunger seal (second seal member), 9G ... Caliper piston seal (first seal member), TR ... Teflon ring.

Claims (8)

In a disc brake device that obtains a braking force by pressing a brake pad against a disc rotor by a caliper piston according to a brake hydraulic pressure supplied to a caliper cylinder,
A disc brake device comprising a brake fluid absorbing mechanism for absorbing brake fluid supplied to the caliper cylinder in a reduced speed region where the brake fluid pressure is low.   The brake fluid absorbing mechanism has a pad pressing member that is pressed against the brake pad by the caliper piston, and is supplied to the caliper cylinder by moving the caliper piston relative to the pad pressing member in a reduced speed region. The disc brake device according to claim 1, wherein the disc brake device is configured to absorb brake fluid.   The disc brake device according to claim 2, wherein the brake fluid absorbing mechanism includes a first elastic member that transmits a pressing force from the caliper piston to the pad pressing member.   4. The disc brake device according to claim 3, wherein the first elastic member has a non-linear spring characteristic.   5. The disc brake device according to claim 3, wherein the brake fluid absorbing mechanism includes a second elastic member that biases the pad pressing member toward the first elastic member.   6. The disc brake device according to claim 5, wherein a spring constant of the second elastic member is set smaller than a spring constant of the first elastic member.   The pad pressing member includes a pressure receiving portion that receives a brake fluid pressure through the pressure receiving portion of the caliper piston, and the pressure receiving area of the pad pressing member is set smaller than the pressure receiving area of the caliper piston. The disc brake device according to any one of claims 1 to 6.   The fitting portion between the pressure receiving portion of the caliper piston and the pressure receiving portion of the pad pressing member has a second seal member having a sliding resistance smaller than that of the first seal member provided between the caliper cylinder and the caliper piston. The disc brake device according to claim 7, wherein the disc brake device is provided.

Images