JPH0152618B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a new and improved automatic adjustment device that allows brake clearance to be precisely increased or decreased by hand from outside the brake when the brake is installed in the operating position on the vehicle body. Concerning new and improved caliper brakes.

Although a number of rotary cam actuators for caliper brakes have been proposed in the past, they suffer from a number of adjustment and maintenance drawbacks. In the actuating device we are interested in, the brake lining is pressed onto the rotor by a threaded post, which engages a threaded nut, which is driven axially by a rotating cam mechanism. In some of these mechanisms, the rotary drive structure of the cam is in sliding contact with the nut portion, and if corrosion or dirt enters the structure, the nut will snap against the rotary drive structure and drive the nut across the threaded post. The clearance cannot be adjusted correctly.

In other configurations, the connection between the nut and the rotary drive structure is such that the post is fixed while the nut is manually and automatically adjusted to adjust the brake clearance. With some of these configurations, the nut cannot be manually moved back to increase clearance without removing the brake from the vehicle body.

These can cause the column to be pushed back to the point where the nut hits the column screw and becomes stuck, causing the automatic adjustment part of the brake to slip without automatically adjusting the brake. If such structures are pneumatically actuated or actuated by other mechanisms in which the movement of the actuating rod is not proportional to the movement of the brake application, the maladjustment may not be perceivable to the driver and the brake application may be uneven. .

According to still other configurations, it is difficult to seal the passage leading through the housing to the adjustment mechanism, and also the threaded nut extends outside the housing.
If the rubber bulkhead type cover is damaged or not sealed for any reason, it will corrode and cause the nuts to bind together.

It is therefore an object of the present invention to provide a new and improved automatic adjuster (hereinafter referred to as "adjustment") of the above type, which cannot be adjusted to a position that renders the automatic adjuster inoperative. It's about doing.

Another object of the invention is that the threaded brake actuating post engages a threaded nut, the nut is moved axially by a rotating cam mechanism, and the threaded nut is rotated in a direction to retract the threaded post. The object of the present invention is to provide a new and improved automatic regulator of the above type in which this type of automatic regulator is avoided.

Still another object of the present invention is to provide an improved caliper brake in which the rotational drive mechanism of the rotary cam slides out of engagement with the threaded nut.

Other objects and benefits will be apparent to those skilled in the art.

Reference numeral 11 generally indicates a cam actuated disc brake constructed in accordance with a first embodiment of the present invention. This brake 11 has a caliper 12 supported adjacent to a rotor 13. The caliper 12 is supported so as to slide axially relative to the rotor 13 but not rotate relative to the rotor.

As is typical in sliding caliper type disc brakes, the caliper 12 has a first leg 14 disposed adjacent one of the braking surfaces of the rotor 13 to which the brake pads are attached in a suitable manner. 15
is fixed. A second leg 16 of caliper 12 is disposed adjacent the other braking surface of the rotor. An actuation mechanism, generally indicated at 17, and an automatic adjustment mechanism, indicated generally at 18, are coupled to the caliper leg 16.
These mechanisms act on a brake pad 19 located opposite the brake pad 15 and cooperating with the adjacent braking surface of the rotor 13.

An elongated hole 21 is formed in the caliper leg 16, and a non-rotating cam member 22 and a rotating cam member 23 are supported in this hole. The rearmost surface (second
A helical cam surface 24 is formed in FIG. Cam member 22 is supported within bore 21 for axial movement but not rotation. This support is provided by a staking pin (FIG. 4) 25 which is held in place at the base of a threaded opening 26 in the caliper leg 16. The pin 25 has a key portion 27 extending into an elongated groove 28 formed in the cam member 22.

The cam member 23 also includes a helical cam surface 29 having a complementary shape to and juxtaposed with the cam surface 24.
(Figure 2). A suitable rolling bearing 31 is interposed between the cam surfaces 29 and 24 to reduce the amount of friction between these cam surfaces.

The surface 32 of the cam member 23 opposite the cam surface 29 engages a rolling bearing 33 which presses against a sealing plug 34 secured to the open end of the bore 21 by a machine screw 35.

A hole 36 extending in the axial direction is formed in the sealing plug 34, and a sleeve bearing 37 and a seal 3 are inserted into this hole.
8 is supported. The actuating shaft 39 passes through the hole 36 and is rotatably supported by a bearing 37. The operating rod 1 is fixed non-rotatably to the operating shaft 39 by a spline machine screw 42. Actuation rod 41 is pivotally mounted to rod 43 of actuation air motor 44 (FIG. 3). The air motor is secured to caliper assembly 12 by bracket 15. As will be described later, the operating motor 44 connects to the operating shaft 39 via the rod 41.
Rotate.

The actuating shaft 39 has a generally hollow cylindrical cross section and has a hole 2
The cam member 23 has a portion 46 extending into the cam member 23 and having a thicker radial diameter. A spline connection 47 connects the hollow cylindrical portion 46 of the actuating shaft to the cam member 23 for simultaneous rotation of these components.

The self-adjusting mechanism 18 includes an annular nut 48 which is connected to a corresponding shoulder 5 formed on the cam member 22.
1 has a shoulder 49 abutting on the shoulder 49 . The external thread 52 of the nut 48 engages with the threaded portion of the external thread member 53.
This externally threaded member 53 has a reduced diameter end that supports a collar 54 which is connected to the brake pad 19.
engages the load distribution device 55 which presses on the load distribution device 55. A suitable boot or dust seal 56 surrounds the collar 54 and is secured to the caliper hole 2 by a retaining ring 57.
1, the retaining ring seals the inner portions of the brake actuation mechanism 17 and the automatic adjustment mechanism 18 provided against the inner end of the bore 21. A helical compression spring 58 is provided between the seal retaining ring 57 and the hat-shaped bearing plate/dust seal 59, the radially outer portion of which presses the cam 22 to retract the brake, as will be described below.

The nut 48 has an axially extending projection 60 with a slot 61 in which the clutch plate 6 is inserted.
one or more tongues 62 of three. Tongue piece 62
There is a certain clearance of about 5 degrees of rotation between the groove and the side surface of the slot 61, and this clearance forms a normal operating clearance for the brake 11, as will be described later.

The clutch plate 63 is a pair of clutch plates 64 and 65.
while these clutch plates 6
4, 65 has a tongue-shaped connection to the hollow cylindrical portion 46 of the actuating shaft 39. This tongue-like connection has tongues 66 formed in clutch plates 64 and 65 (FIG. 5) and a slot 67 formed in hollow cylindrical portion 46. Snap ring 68 presses against clutch plate 64 and is secured within a groove in hollow cylindrical portion 46. The large compression spring 69 is the clutch plate 6
5 and the shoulder 71 formed at the base of the hollow cylindrical portion 46. Spring 69 presets the pressure that exists between clutch plates 64, 65 and clutch plate 63, and also sets the torque at which this clutch begins to slip, as will be described below.

As the actuating shaft 39 rotates forward, it rotates the nut 48 forward through the clutch plate 63, removing a 5 degree lost motion clearance between the tongue 62 and the side of the slot 61 in the nut. Because this 5 degree lost motion occurs at the beginning of each actuation, a device is provided to prevent the nut from rotating backwards when the actuating shaft 39 is rotated backwards. In the embodiment shown in FIGS. 1-5, for this purpose the nut 48
This is done using a spring brake 72 having a projection 73 surrounding the cam member and fixed to the non-rotating cam member.
This spring brake 72 acts as a one-way brake, allowing the nut 48 to rotate in the forward direction but not in the reverse direction. During the initial reverse rotation, the reaction force generated by the brake lining of the rotor 13 forces the shoulder 49 of the nut onto the actuating cam member 2.
2 to prevent rotation of the nut. After that, the nut 48 separates from the shoulder 51,
The spring brake prevents the nut 48 from rotating. During this time, the shoulder 49 of the nut separates from the shoulder 51, while the front surface of the nut 48 engages the washer 59, which then reliably retracts the nut and push rod 53 to create normal operating clearance for the brake. do. In the embodiment shown in FIGS. 1-5, the clearance between shoulders 49 and 51 is then 0.015 inches. During this disengagement movement of shaft 39, clutch discs 64 and 65
is rotated clockwise as shown in FIG. 5 to move the tongue 62 of the clutch plate 63 into engagement with the rear edge of the slot 61. During subsequent actuation, tongue 62 will therefore rotate a full five degrees counterclockwise as shown in FIG. 5 until it engages the front edge of slot 61.
The previously mentioned clearance between shoulders 49 and 51 prevents the nut and cam member 22 from joining during automatic adjustment.

One of the problems with conventional slack adjuster construction is that the threaded portion of push rod 53 is not accessible after the brake is installed. In the structure of the present invention, the non-rotating cam member 22 is connected to the nut 4.
The rotating cam member 23 is provided adjacent to the rotating cam member 8 and is provided outside the non-rotating cam member 22 . According to this construction, the rotating cam member 23 can be moved away from the brake rotor by means of an axially extending shaft passing through the outer wall of the actuating device, and this actuating adjustment mechanism is connected to the sealing plug 34 and the inner seal of the brake. provided between the structure. This sealing structure has a hat-shaped washer 59. According to a feature of the present invention, the outer periphery of the washer 59 is always in sliding contact with the non-rotating cam member 22, and the central portion of the washer 59 is in a non-sliding, non-rotating tight fit with the push rod 53. Therefore, washer 59 acts as a metal sliding seal to protect the internal functions of the brake, while acting as a friction clutch to prevent rotation of push rod 53 by nut 48. In some conventional designs, the push rod 53 must be held against rotation by a sliding structure located adjacent to the rotor 13 and submerged in water or dust.

According to another feature of the invention, the normal operating clearance of the brake can be adjusted by rotating the push rod 53 relative to the nut 48 while the brake remains on the rotor. This operation is performed by a torque transmitting surface 74, which in this embodiment is connected to the push rod 53.
It is a slot for a screwdriver at the end of the. The screwdriver slot 5 is inserted through the passage 75 passing through the center of the operating shaft 39.
4 is accessible and its outer end is sealed by a machine screw 42.

There are cases where the push rod 53 is returned unknowingly and pressed against the operating shaft 39, causing it to become immobile. In this case, the connection between the push rod 53 and the actuating shaft is such that the clutch plates 63, 64, and 65 slip without being able to adjust the nut 48. When this happens, of course, the brakes lose their self-adjusting properties.

In the embodiment shown in FIGS. 1-5, in order to prevent this, teeth are provided on the abutting surface of the push rod and the abutting surface of the operating shaft to prevent the push rod from rotating and becoming jammed. In the illustrated embodiment, this objective is achieved by providing an annular ring 76 surrounding the passageway 75 and having square teeth 77 on its abutment surface. A contact portion 78 is provided at the end of the push rod 53 to engage square teeth, and the contact surface thereof is provided with ratchet teeth 79, and the flat side of the tooth engages with the flat side of the square tooth 77.
3 is restricted from retreating toward the annular ring 76 side. However, the ratchet teeth 79 allow the self-adjusting mechanism to easily rotate the push rod 53 away from the annular ring 76.

According to the present invention, brake pads can be easily replaced. Remove machine screw 42 from passage 75, insert a screwdriver into slot 74, and turn push rod 53 counterclockwise as shown in FIGS. 4 and 5. In this way, the rod 53 is returned from the nut 48 to create a clearance between the pads 15, 19 and the rotor 13. Replace the brake assembly on the vehicle by inserting new pads 15 and 19 and rotating the threaded adjustment of push rod 53 clockwise until the brake pads are close to rotor 13. As the threaded adjustment portion of the push rod 53 is rotated with a screwdriver, the movement causes the washer 59 and the spring 5 against the non-rotating cam member 22.
This is prevented by sliding contact with the tightening action of 8. This frictional engagement holds the threaded adjustment portion of the push rod 53 in its adjustment position, and the clutch plates 63, 6
4 and 65 are then actuated to rotate nut 48 against the threaded adjustment of push rod 53. Reinstall the machine screws 42 to seal the device and prevent water and dust from entering.

The operation of the embodiment shown in FIGS. 1-5 will be explained.

Each figure shows the brake 11 in the released position. To operate the brake, as shown in Figure 3-5, the piston rod 43 is extended and the operating rod 41 and operating shaft 39 are rotated counterclockwise. As a result, the cam member 23 is rotated relative to the cam member 22 and an axial force is applied to the cam member 22. Therefore, the cam member 22 moves to the left together with the nut 48 and the externally threaded push rod 53 to compress the spring 58. Then, the brake pad 19 is connected to the rotor 13.
The caliper 12 is engaged with the braking surface of the caliper 12 and applies a reaction force to the caliper 12, causing it to slide to the right as shown in FIG. Brake pads 15 are therefore engaged with opposing braking surfaces of rotor 13.

As cam member 23 rotates, clutch plates 64 and 65 also cause clutch plate 63 to rotate. If the lining is not worn enough to require adjustment, the tongue 62 of the clutch plate 63 will simply traverse the slot 61 and the nut 48 will not rotate.

However, if the lining is worn enough to require adjustment, clutch plate 63 will eliminate clearance in slot 61 and rotate nut 48 in the adjustment direction. This rotation is caused by the slippage of the one-way spring brake 72. Rotation of the nut 48 causes the advance of a push rod 53 which eliminates clearance, and this push rod is prevented from rotating by a washer 59 and a compression spring 58.
If the brake pads 15 and 19 engage the braking surface of the rotor with a constant pressure set by the spring 69,
Cam 23 rotates continuously in the actuation direction to slide clutch plates 64 and 65 against clutch plate 63. Therefore, no overregulation occurs.

When the adjustment is made as described above, the cam member 23
The brake is released by rotating in the opposite direction. In this manner, cam surfaces 29 and 24, by means of spring 58, return cam member 22, along with nut 48 and push rod 53, to its rest position. but,
The one-way spring brake 72 prevents the nut 48 from rotating in the counteradjustment direction. The nut 48 is thus held in its new adjusted position relative to the threaded portion of the push rod 53.

The embodiment shown in FIG. 6 will be explained.

The embodiment shown in FIG. 6 corresponds generally to the embodiment shown in FIGS. 1-5, except that a lost motion connection arrangement is utilized. Portions of the embodiment shown in FIG. 6 that correspond to the same parts of the embodiment shown in FIGS. 1-5 are designated by the same reference numerals with the addition of an "a".

FIG. 6 shows a lost motion connection type used in place of the clearance between tongue 62 and slot 61. In the embodiment shown in FIG. 6, the tongue 62 substantially fills the slot 62 such that 5 degrees of lost motion is less than the clearance between the projection 73a of the spring brake 72a and the retaining surface of the non-rotating cam member 22a. can get.

The operation of the embodiment shown in FIG. 6 is similar to that of the apparatus shown in FIGS. 1-5, except where the air movement is performed.

Next, the embodiments shown in FIGS. 7 and 8 will be described. The embodiment shown in FIGS. 7 and 8 roughly corresponds to the previous embodiments, except that the tightening spring of the clutch is located on the inside of the clutch plate instead of on the outside as in the previous embodiments. The difference is that it is provided in Parts shown in FIGS. 7 and 8 that are the same as corresponding parts in the embodiment shown in FIGS. 1 to 6 are designated by the symbol "b".
Indicated with.

In the embodiment shown in FIGS. 7 and 8, the nut 48b is elongated and a compression spring 69b is provided between the inner clutch plate 64b and an annular spring retaining member 81, which is attached to the nut 48.
against the outward facing shoulder 82 of b. In order to locate the spring 69b between two surfaces that do not rotate relative to each other, the clutch plates 64b and 65b are connected to the actuating shaft 39.
b is slidably coupled to nut 48b. The inner periphery of clutch plates 64b and 65b includes tongues 6 that are received within slots 61b of nuts 48b.
The clutch plate 63b has tongues 82 on its outer periphery, and these tongues support the rotating cam member 23.
It is received in the slot 83 on the inner circumference of b. Actuation shaft 39b also has teeth that engage spline connection 47b of rotating cam member 23b. The advantage of this construction is that the actuating shaft 39b has a hollow cylindrical portion 46b that is considerably shorter than in the previous embodiment.

Clutch plates 64b and 65b are snap springs 8
4 to the nut 48b, a snap spring 84 is disposed outwardly of the clutch plate 65b and is received within a groove 85 in the outer end of the nut 48b. Further, in the embodiment shown in FIGS. 7 and 8, the collar 54 is not used and the push rod 5
The inner end portion of the dust seal 56b is expanded to serve as a holding portion for the dust seal 56b. Also, the sleep bearing 37 in the embodiment described above is replaced with two bearings 86, and these roller bearings are replaced by the drive shaft 39b as in the embodiment described above.
In addition to supporting and positioning the rotating cam member 2, the interference spring spline connection portion 47b
3b is removed from sliding engagement with the side wall of hole 21b. A lost motion of 5 degrees is obtained between the tongue piece 82 of the clutch plate 63b and the side wall of the groove.

In the embodiment described above, the side wall of the slotted hole 21 is slightly widened (87) over the rotating portion of the cam actuating member so that the actuating shaft 39 does not engage slidingly with the housing. The splines 47 between the rotary cam member 23 and the hollow cylinder 46 of the actuation shaft are a sliding tight fit so that the rotary cam 23 is spaced from the side wall of the hole 87. On the other hand, the non-rotating cam member 22
is in contact with the side wall of the hole 21, and the push rod 53 is disposed on the center line of the actuating mechanism 17 with the nut 48 as a bearing. Additionally, the structure of the present invention seals the friction drive mechanism between the sliding washer 59 and the rotary seal 38 surrounding the actuating shaft 39 so that the torque produced by the friction device does not change appreciably during use. Furthermore, the operating mechanism remains attached to the vehicle body,
The actuation mechanism within the housing can also be manually adjusted from outside the housing via a passage through the actuation shaft.

Although the present invention has been described in detail above, it is not intended to be limited to the specific embodiments illustrated, and novel applications of the present invention that fall within the scope of practice in the technical field to which this invention pertains and further fall within the scope of the claims. , including variations and configurations.

[Brief explanation of drawings]

1 is a longitudinal cross-sectional view of a rotary cam actuated disc brake incorporating the principles of the present invention; FIG. 2 is an exploded view of portions of the self-adjusting device shown in FIG. 1; and FIG. FIG. 2 is a front view of the pneumatic actuating device for brakes in the embodiment shown, FIG. 4 is a cross-sectional view taken approximately along the line 4--4 in FIG. 1, and FIG. 5 is a lost motion connection of the automatic adjustment device. FIG. 6 is a partial enlarged view showing another embodiment of the lost motion connection, and FIG. 7 is similar to FIG. 1. FIG. 8 is a partially enlarged sectional view taken approximately along line 8--8 in FIG. 7. In the symbols shown in the drawings: 11...disc brake, 12...caliper housing, 13...
Rotor, 14, 16... Leg, 15, 19... Brake pad, 17... Actuation mechanism, 18... Automatic adjustment device, 22... Non-rotating cam member, 23... Rotating cam member, 30, 33... Rolling Bearing, 34...
... Plug, 37 ... Sleeve bearing, 38 ... Seal, 41 ... Operating rod, 44 ... Air motor, 47
... Spline connection part, 48 ... Nut, 52 ...
...Female thread member, 53...Push rod having a male thread cut portion, 54...Collar, 57
... Retaining ring, 58 ... Compression spring, 59 ... Dust seal, 62 ... Tongue piece, 63, 64, 65 ...
...clutch plate, 68,84...snap spring,
72... Spring brake, 75... Passage, 77...
Square teeth, 79... ratchet teeth.

Claims (1)

[Claims] 1. A rotor 13 that rotates around an axis and has a friction surface; friction element members 15, 19, 55 for frictionally engaging with the friction surface of the rotor; an annular rotating cam member 23; and a hollow cylindrical portion 4 coaxially disposed within and rotatably intermeshed with the rotating cam member;
an annular non-rotating cam member 22 which is in contact with the actuating member and moves axially in the forward braking application direction by rotation of the actuating member; a connected push rod 53, the push rod being disposed coaxially with and surrounded by both the rotating and non-rotating cam members; being surrounded by and threaded into the push rod; mated annular nut 48 having a shaft portion coaxially disposed within both the rotating and non-rotating cam members and a radially extending flange in contact with the non-rotating cam members; 49
and wherein in response to rotation of the actuating member, the non-rotating cam member moves the annular nut and push rod combination in the forward braking direction to engage the friction element member with the rotor friction surface. and a mechanically actuated disc brake 11 having members 58, 59 for biasing the annular nut and push rod combination upon rearward brake release by reverse rotation of the actuating member; an adjusting member that rotates the annular nut relative to the push rod to advance the push rod forward relative to the annular nut, the adjustment member surrounding and engaging the annular nut; and the actuating member; clutch plate assembly 63,6 actuated by
4,65, a lost motion member; an adjustment member for advancing the push rod relative to the annular nut after the actuating member has rotated a predetermined amount; and an adjustment member for advancing the push rod relative to the annular nut; a one-way brake member 72 that frictionally resists retraction of the mechanically actuated disc brake. 2. An annular inner clutch plate 63 with which the clutch plate assembly frictionally engages outer clutch plates 64, 65 on both sides, and thus the inner and outer clutch plates 6.
3, 64, 65 have a compression spring 69 extending annularly between the annular nut and the hollow cylindrical portion 46 and frictionally engaging the outer clutch plate against the inner clutch plate. at least one outwardly directed tongue 66 and the lost motion member projecting radially outwardly from each of the outer clutch plates and engaging an axial slot 67 in the hollow cylindrical portion; at least one inwardly directed tongue 6 projecting radially inwardly from the inner clutch plate and engaging an axial slot 61 in the annular nut;
2, the circumferential width of the axial slot of the annular nut is greater than the circumferential width of the inwardly directed tongue, and the annular nut The first claim is characterized in that the push rod rotates with respect to the push rod.
Mechanically actuated disc brakes as described in Section. 3. An annular inner clutch plate 63 with which the clutch plate assembly frictionally engages outer clutch plates 64, 65 on both sides, and thus the inner and outer clutch plates 6.
3, 64, 65 have a compression spring 69 extending annularly between the annular nut and the hollow cylindrical portion 46 and frictionally engaging the outer clutch plate against the inner clutch plate. at least one outwardly directed tongue 66 and the lost motion member projecting radially outwardly from each of the outer clutch plates and engaging an axial slot 67 in the hollow cylindrical portion; at least one inwardly directed tongue 62 projecting radially inwardly from the inner clutch plate and engaging an axial slot 61 in the annular nut;
and wherein the circumferential width of the axial slot in the hollow cylindrical portion is greater than the circumferential width of the outwardly directed tongue, and the actuating member rotates a predetermined amount such that the annular A mechanically actuated disc brake according to claim 1, wherein the nut rotates relative to the push rod. 4. An annular inner clutch plate 63b in which the clutch plate assembly is in frictional engagement with outer clutch plates 64b, 65b on both sides, such that the inner and outer clutch plates 63b, 64b, 65b are in contact with the annular nut 48 and the rotational nut 48; extending in an annular shape between the cam member 23b and the cam member 23b.
and a compression spring 69b for frictionally engaging the outer clutch plate with the inner clutch plate; and the lost motion member projects radially inwardly from each of the outer clutch plates. and at least one inwardly directed tongue 66b engaging an axial slot 61b of the nut and at least one outer tongue projecting radially outwardly from the inner clutch plate and engaging an axial slot 83 of the rotating cam member. oriented tongues 82, the circumferential width of the axial slot of the rotating cam member is greater than the circumferential width of the inwardly directed tongues, and the actuating member rotates a predetermined amount. 2. A mechanically actuated disc brake according to claim 1, wherein said annular nut subsequently rotates relative to said push rod. 5 an annular inner clutch plate 63 with which the clutch plate assembly frictionally engages outer clutch plates 64, 65 on both sides;
3, 64, 65 have a compression spring 69 extending annularly between the annular nut and the hollow cylindrical portion 46 and frictionally engaging the outer clutch plate against the inner clutch plate. and the one-way brake member comprises a helical spring brake 72a surrounding at least a portion of the annular nut shaft portion 48a, and the lost motion member comprises a radial spring brake 72a on one end of the helical spring brake. a protrusion 73a which engages an axial slot in the non-rotating cam member 22a, the circumferential width of the axial slot in the non-rotating cam member being greater than the circumferential width of the protrusion; 2. A mechanically actuated disc brake according to claim 1, wherein said actuating member rotates a predetermined amount before said annular nut rotates relative to said push rod.