US3017866A

US3017866A - Fluid pressure operated motor

Info

Publication number: US3017866A
Application number: US831246A
Authority: US
Inventors: Stelzer William
Original assignee: Kelsey Hayes Co
Current assignee: Kelsey Hayes Co
Priority date: 1959-08-03
Filing date: 1959-08-03
Publication date: 1962-01-23
Anticipated expiration: 1979-01-23

Description

Jan. 23, 1962 w. STELZER 3,017,866

FLUID PRESSURE OPERATED MOTOR Filed Aug. 3, 1959 3 Sheets-Sheet 1 ATTORNEY Jan. 23, 1962 Filed Aug. 3, 1959 W. STELZER FLUID PRESSURE OPERATED MOTOR 3 Sheets-Sheet 2 I3 \9 g 24 H 22 \oo a7 3% {O 61 82 \o a e5 $0 53 5n 3 5340 4a, 5 9o mm 58 41 444 L? as 77 \5 G I INVENTOR WILL/AM 6 TELZEE ATTORNEY Jan. 23, 1962 Filed Aug. 5, 1959 W. STELZER FLUID PRESSURE OPERATED MOTOR 3 Sheets-Sheet 3 INVENTOR 4 WILL/AM 5TELZEE ATTORNEY United States tent @tice 3,017,866 FLUID PRESSURE OPERATED MGTOR William Stelzer, Bloomfield Hills, Mich, assignor to Kelsey-Hayes Company, Detroit, Mich, a corporation of Delaware Filed Aug. 3, 1959, Ser. No. 831,246 10 Claims. ((31. 121-41 This invention relates to a fluid pressure operated motor and more particularly to such a motor especially adapted for use in operating motor vehicle brakes.

There are two general types of vehicle booster brake motors of the elastic fluid pressure type in common use. One such motor is of the air suspended type in which motor chambers on opposite sides of the motor piston are normally at atmospheric pressure and the motor is operated by exhausting air from one of said chambers to create differential pressures on opposite sides of the motor piston. The other type of motor is of the vacuum suspended type in which the motor chambers on opposite sides of the piston thereof are normally evacuated and motor operation is effected by admitting air to one of the motor chambers. Generally speaking, the air suspended type of motor has certain advantages, such as simplicity, over the vacuum suspended type, but is somewhat disadvantageous as compared with the vacuum suspended type since the latter responds much more rapidly to operation of the control valve mechanism which admits air to one of the motor chambers.

An important object of the present invention is to provide a motor of the air suspended type which possesses the advantage of a vacuum suspended motor in that it provides for the more rapid evacuation of one of the motor chambers upon operation of the control valve mechanism.

More specifically, an object of the invention is to provide an air suspended motor having embodied as a part thereof a vacuum reservoir of substantial capacity, connected to a source of vacuum, such as the intake manifold of the vehicle engine, to be normally evacuated and connectible to the variable pressure chamber of the mtor upon operation of the valve mechanism to eflFect an extremely rapid evacuation of such chamber of the motor.

A further object is to provide a motor of this type wherein the pressure responsive unit of the motor, which divides the casing thereof to provide a constant pressure chamber and a control or variable pressure chamber, is provided with a vacuum reservoir of substantial capacity whereby, when the follow-up control valve mechanism of the motor is operated, the control or variable pressure chamber of the motor is connected to the vacuum reservoir referred to, to effect a rapid evacuation of the motor control chamber, such evacuation being much more rapid than is true of aconven'tional air suspended motor in which a vacuum line is connected to the motor control chamber upon operation of the valve mechanism.

Other objects and advantages of the invention will become apparent during the course of the following description.

In the drawings I have shown one embodiment of the invention. In this showing:

FIGURE 1 is a diagrammatic view showing the braking system of a motor vehicle as a whole including the motor of the present invention;

FIGURE 2 is an enlarged fragmentary axial sectional view through the motor and associated elements, the parts being shown in normal otf positions;

FIGURE 3 is a fragmentary sectional view of a portion of a motor showing the parts in operative positions; and

lifil'hdiiii Patented Jan. 23, 1%62 FEGURE 4 is a section on line 4-4 of FIGURE 2.

Referring to FIGURE 2, the numeral 10 designates the motor as a whole comprising casing sections 11 and i2 suitably connected together as at 13 by any desired type of casing connection, forming no part of the present invention. The motor is provided therein with a pressure responsive unit indicated as a whole by the numeral l4. Such unit comprises an annular shell 15 shaped in cross section as shown in FIGURE 2 and providing therein a vacuum reservoir 16 of substantial capacity. The body or shell 15 is connected to the inner bead 17 of a rolling diaphragm 18 the outer periphery of which is provided with a bead 19 clamped between the casing sections ill and 12. An elbow 22 is connected to and communicates with the shell 15 and has its outer end connected by a flexible hose 23 with a source of vacuum such as the intake manifold of the vehicle engine. It will become apparent that the elbow 22 moves with the pressure responsive unit and the casing 12 is provided with a slot 24 to accommodate movement of the elbow 22.

The pressure responsive unit further comprises preferably die-cast

body members

28 and 29 secured together as at 30. These body sections provide an internal annular chamber 311 in fixed communication with the reservoir 16 through a passage 32.

The body member 29 is provided with an annular valve seat 33 normally engaged by a resilient annular valve 34. This valve is carried by a body 35 sealed with respect to the body 28 by an annular diaphragm 36. The valve 34 is biased to the right to its normal position in FEGURE 2 by a spring 37. A space radially within the valve seat 33 forms a chamber 40 for a purpose to be described.

An axially movable pedal operable member 42 is slidable in the body 29, such body being provided with an annular flange 43 forming a bearing for the member 42. An annular flange 44 on the member 42 engages the bearing 43 to limit movement of the member 42 to its off position shown in FIGURE 2.

The member 42 is provided with an annular valve seat to radially inwardly of and concentric with the valve seat 33. The space Within the valve seat 46 communicates through a port 47 with a space 43 within the member 42, such space being open to the atmosphere, as described below. i

Movement of the body 42 to the left of its oil position in FIGURE 2 is effected .by means of a rod 50 projecting axially through the space 48 and connected in any suitable manner with the member 42. Such connection in the present case includes a spherical head 51 and an adjacent resilient collar 4-2, both arranged in a pilot extension 53 formed integral with the member 42 and slidable in a bore 54 formed in an axial extension 5'5, preferably integral with the body member 28. A spring 56 biases the pilot extension 53 and member 42 rearwardly or to the right in FIGURE 2.

A plate 60 is rigidly fixed to the member 42 and is provided with circumferentially spaced openings 61 through which project pins 62 (FIGURES 2 and 4') fixed to the body 29, for a purpose to be described. Against the plate 60 is arranged an annular diaphragm 64 having its inner periphery secured with respect to the

bodies

28 and 29 as shown in FIGURE '2. The outer periphery of the diaphragm 64 is provided with a relatively heavy head 65, one side of which is formed as an annular flange 66 normally spaced from, but movable into engagement with, the adjacent wall 67 of the shell 15. The flange 66 is grooved as at 68 (see the lower portion of FIGURE 2) to maintain, under :all conditions, communication between the space 69 to the left i f the diaphragm 64 and the constant pressure chamber 70 of the motor in which atmospheric pressure is always present. At the side of the pressure responsive unit 14 opposite the chamber 70, the motor is provided with a control or variable pressure chamber 71 which communicates with the chamber 70, under conditions to be described, when the motor is inoperative, the chamber 71 ;being connectible to the vacuum reservoir 16 to eiiect operation of the motor.

A second annular plate 75 at its inner periphery normally seats against a snap ring 76 carried by the member 42. The plate 75 has its outer periphery seating in an annular groove 77 in the diaphragm bead 65. A cover plate 80 has its inner periphery bonded to a sealing diaphragm 81 surrounding and snugly fitting the rod 50, the

plates

75 and 80 forming therebetween an air chamber 82. The plate 80 has its outer periphery fixed relative to the plate 75 by threaded studs 84, the heads 85 of which are preferably welded to the plate 75. These stud heads, therefore, serve to space the outer periphery of the plate 80 from the plate 75, thus providing an air passage or passages 86 communicating with the constant pressure motor chamber 70, which in turn is always open to the atmosphere through the slot 24. An annular air cleaner 87 is arranged between the

plates

75 and 80, thus supplying clean air to the space 48. The plate 80 is biased to the right in FIGURE 2 by a spring 90, and since the plate 80 is fixed to the plate 75, this spring biases the radially inner periphery of the plate 75 into engagement with the snap ring 76.

The plate 75 is shouldered as at 94, and between such shoulder and the member 42 is arranged an annular diaphragm 95. Such diaphragm forms with the plate 75 a chamber 96 open to the chamber 82 as at 97. An annular pressure plate 98 is fixed to the diaphragm 95 and constantly engages the adjacent ends of the pins 62 for a purpose to be described.

A chamber 100 is formed between the

plates

60 and 75 and is in fixed communication with the motor control chamber 71 through openings 61 and through a passage 101 formed through the

body members

28 and 29. The chamber 100 also is in fixed communication with the valve chamber 40 through a passage 102.

Since the valve chamber 40 normally is in communi cation with,the atmosphere through passage 47, space 48 and air chamber 82, and since the valve chamber 40 normally communicates with the motor chamber 71 through

passages

102 and 101, it will be noted that atmospheric pressure is normally present in the

motor chambers

70 and 71. The pressure responsive unit is biased to the OE position shown by a return spring 105, and the motor casing 12 may be provided with circumferentially spaced rubber bumpers 106 against which the outer periphery of the shell 15 is normally seated.

The left-hand end of the axial extension 55 (FIGURE 2) terminates in a master cylinder plunger 110 operable in a master cylinder 111 provided with the usual reservoir 112. Operation of the motor displaces fluid from a master cylinder chamber 113 through lines 114 to the vehicle Wheel cylinders 115 (FIGURE 1). Operation of the valve mechanism of the motor is effected through depression of a brake pedal 116 pivoted as at 117 to the push rod 50. This rod is preferably connected to the motor casing 12 by a conventional flexible boot 118.

Operation The

motor chambers

70 and 71 are normally at atmospheric pressure, as stated above. Operation of the motor is effected by depressing the brake pedal 116 to operate the rod 50 and thus transmit movement to the member 42 to move it to the left in FIGURE 2. Initial movement of the member 42 engages the valve seat 46 with the valve 34, thus disconnecting the valve chamber 40 from the atmospheric passage 47. The valve parts will now be in lap position. Slight additional movement of the member 42 will cause the valve seat 46 to move the valve 34 to the left away from the seat 33, thus cracking the valve chamber 40 to the chamber 31. This chamber is in fixed communication with the vacuum reservoir 16 through the passage 32, and accordingly air will be exhausted from the motor chamber 71 through

passages

101 and 102. It will be noted in this connection that the diaphragm 64, plate and diaphragm seal the

passages

101 and 102 from the motor chamber 70, and accordingly pressure in the chamber 71 will be controlled, as described, by operation of the valve mechanism.

The exhaustion of air from the chamber 71 establishes differential pressures on opposite sides of the pressure responsive unit 14, and such unit accordingly moves to the left in FIGURE 2 to operate the plunger 110, thus displacing fluid from the chamber 113 into the brake lines 114 and thus to the wheel cylinders 115 to apply the brakes. Obviously, the valve mechanism provides a follow-up action of the pressure responsive unit 14 and the plunger 110 with respect to the pedal operable rod 50. If pressure is to be applied to the plunger 110 beyond the point at which maximum energization of the motor takes place, forces applied to the pilot extension 53 will transmit forces direct to the axial extension 55, as will be obvious.

When the brakes are to be released, the operator will release the pedal 116, whereupon the spring 56 will move the valve seat 46 to the right. The spring 37 will cause the valve 34 to follow such movement until the valve engages the seat 33,-whereupon the valve seat 46 will move away from the valve 34 to connect the motor chamber 71 to the atmosphere. The return spring 105 will move the pressure responsive unit to its oil position, such movement being limited and silenced by the rubber bumpers 106.

The means comprising the diaphragm 64, plate 75, etc. provides for reaction against the brake pedal. Such means will be generally described, but forms no part of the present invention, being disclosed and claimed in my copending application Serial No. 832,287, filed August 7, 1959, now Patent No. 2,976,850. As previously stated, the pressure plate 98 is always in engagement with the pins 62. Upon initial operation of the valve mechanism to energize the motor, air will be exhausted from the chamber 100, which communicates with the passage 102 through openings 61. Atmospheric pressure in the chamber 96 acting against the diaphragm 95 applies pressure to the body 29 through the pins 62. The purpose of the diaphragm 95 is to subtract from the effective pressure areas of the plate 75 for a purpose to be described.

Atmospheric pressure acts on the remote faces of the diaphragm 64 and plate 75 while sub-atmospheric pressure will exist in the chamber upon operation of the valve mechanism. The effective pressure areas of the diaphram 64 and the plate 75 may be such as to balance each other so as to transmit no reaction force tending to oppose movement of the rod 50. It will be noted that atmospheric pressure acting on the remote faces of the diaphragm 64 and plate 75 tend to move these elements toward each other, but such movement is opposed by the counter-reaction spring 90. Thus the

plates

60 and 75 move as a unit during initial operation of the mechanism. When differential pressures alfecting the pressure responsive unit increase incident to engagement of the brake shoes with the brake drums, pressure acting against the right-hand face of the plate 75 (FIG- URES 2 and 3) will move this plate against the loading of the spring 90, whereupon the flange 66 engages the wall 67 of the shell 15, as shown in FIGURE 3. From this point on, there will be no balancing pressures affecting the diaphragm 64 and its plate 60 and the plate 75,

'and there will be a net pressure acting to the right against the diaphragm 64 and plate 60, which will be transmitted to the rod 50 to provide reaction against the brake pedal. In some installations, it is desirable to provide initial brake reaction. Under such conditions, the diaphragm 95 will be made of larger area to reduce the effective area of the plate 75 open to atmospheric pressure in the chamber 70. With such an arrangement, there will be an initial net pressure acting to the right against the diaphragm 64 and plate 60 to provide some reaction against the brake pedal, which reaction will be increased when the flange 66 engages the wall 67.

As previously stated, the. reaction means just generally described forms per so no part of the present invention, but is disclosed and claimed in the copending application identified above. The important feature of the present invention lies in the provision of a motor which has the advantages of an air-suspended motor, but which provides the advantage of a vacuum-suspended motor in that it effects an extremely rapid evacuation of the motor chamber 71 when the valve mechanism is operated. In other words, if the vacuum line from the intake manifold were connected directly to the chamber 31, an appreciable time element would be required for the evacuation of the motor chamber 71. This disadvantage is overcome by providing the vacuum reservoir 16 as a part of the motor, and more specifically as a part of the pressure responsive unit. This reservoir is of substantial capacity, and it will be apparent that when the valve seat 46 is closed and the valve seat 33 opened, air will be almost instantaneously evacuated from the chamber 71. Accordingly there will be provided an extremely rapid response of the motor to operation of the valve mechanism, substantially the same as takes place in the operation of the valve mechanism of a vacuum-suspended motor. Moreover, with a conventional check valve arranged in the vacuum line to the intake manifold, the reservoir 16 serves to provide what may be termed reserve vacuum so that if the vehicle engine stalls, the reserve capacity of the reservoir 16 will provide for the operation of the brakes without the necessity for using a conventional reserve vacuum tank in conjunction with the system. The cost of such reserve vacuum tank is substantial, Whereas the formation of the shell adds little or nothing to the expense involved in the manufacture of the present motor. Obviously, the construction eliminates the disadvantage of a dead space of substantial volume which has to be evacuated each time the brake is operated, thus requiring less vacuum to operate the motor. At the same time, atmospheric pressure in the motor chamber 71 when the mechanism is inoperative eliminates sealing troubles sometimes occurring in vacuum suspended motors, through which leakage of brake fluid occurs around the master cylinder plunger. Moreover, while the reservoir 16 provides for substantially instantaneous evacuation of the chamber 71 to provide a rapid response of the motor to operation of the brake pedal, re-evacuation of the reservoir 16 occurs very rapidly through exhaustion of air through the pipe 23 to restore normal reservoir conditions. As a matter of fact, this occurs during brake operation, and accordingly the reserve of vacuum is always ready for use.

It is to be understood that the form of the invention shown and described is to be taken as a preferred example of the same and that various changes in the shape, size, and arrangement of the parts may be made as do not depart from the spirit of the invention or the scope of the appended claims.

I claim:

1. A fluid pressure motor mechanism comprising a casing, a pressure responsive unit therein dividing said casing to form a constant pressure chamber and a control chamber, said pressure responsive unit having a fluid reservoir therein connectible to a source of pressure differ ent from the atmosphere, and a control valve mechanism comprising a body and having connection with said chambers and with said reservoir and normally connecting said chambers to each other to balance pressures on opposite sides of said pressure responsive unit, said reservoir being of relatively small internal diameter and having its inner periphery fixed to said valve body, said reservoir being of relatively large external diameter and of substantial length axially of the motor mechanism, said valve mechanism being operable to disconnect said chambers from each other and connect said control chamber to said reservoir to effect a rapid motor-energizing change of pressure in said control chamber.

2. A mechanism according to claim 1 wherein said constant pressure chamber communicates with the atmosphere, said reservoir being a vacuum reservoir connectible to a source of vacuum whereby operation of said valve mechanism effects a rapid evacuation of said control chamber.

3. A fluid pressure motor mechanism comprising a casing, a pressure responsive unit therein dividing said casing to form a constant pressure chamber and a control chamber, said pressure responsive unit comprising a,

radially relatively small axial member and a radially outer shell fixed at its inner periphery to said axial member and forming a fluid reservoir connectible to a source of pressure different from the atmosphere, said reservoir being of relatvely large external diameter and of substantial length axially of the motor mechanism, a control valve mechanism carried by said axial member and having a valve chamber in fixed communication with said control chamber and normally communicating with said constant pressure chamber, said valve mechanism having a second chamber communicating with said reservoir and normally disconnected from said valve chamber, said valve mechanism comprising a manually operable element movable from normal position to disconnect said valve chamber from said constant pressure chamber and connect it to said second chamber to efiect a rapid motor-energizing change in pressure in said control chamber.

4. A mechanism according to claim 3 wherein said constant pressure chamber is open to' the atmosphere, said reservoir being a vacuum reservoir connectible to a source of vacuum whereby the opening of said valve chamber to said second chamber eifects a rapid evacuation of said control chamber.

5. A mechanism according to claim 3 provided with means connected to said manually operable member and exposed to pressures in said constant pressure and control chambers to oppose movement of said manually operable member away from normal position after said valve chamber has been connected to said second chamber.

6. A mechanism according to claim 3 wherein said constant pressure chamber is open to the atmosphere, said reservoir being a vacuum reservoir connectible to a source of vacuum whereby the opening of said valve chamber to said second chamber effects a rapid evacuation of said control chamber, and fluid pressure responsive means exposed to pressures in said control and constant pressure chambers to oppose movement of said manually operable member away from normal position after said valve chamber has been connected to said second chamber.

7. A fluid pressure rnotor comprising a casing and a pressure responsive unit forming therewith a control chamber, said pressure responsive unit comprising an axial member of relatively small diameter and a radially outer annular shell of relatively large external diameter, said shell being fixed at its inner periphery to said axial member and forming therewithin a reservoir of substantial size radially and longitudinally of the motor mechanism, means for connecting the interior of said shell to a source of pressure different from the atmosphere, and a control valve mechanism carried by said axial member and having connection with said control chamber, said reservoir and the atmosphere and normally connecting said control chamber to the atmosphere, said valve mechanism being operative for disconnecting said control chamber from the atmosphere and connecting it to said reserfluid pressure responsive means exposed to pressure in said control chamber and to the atmosphere and connected to said valve mechanism to oppose motor energizing movement thereof.

10. A fluid pressure motor comprising a casing of substantial diameter, a pressure responsive unit therein dividing said casing to form a constant pressure chamber and a control chamber, said pressure responsive unit comprising a radially relatively small axial member and a radially outer annular shell of relatively large external diameter having an external substantially cylindrical surface of slightly smaller diameter than said casing and coaxial therewith, said shell being fixed at its inner periphery to said axial member and forming therewith a reservoir of substantial size radially and longitudinally of the motor mechanism, said pressure responsive unit further comprising a rolling diaphragmhaving an inner portion lying over and fixed at one end to said cylindrical shell portion and secured at its other end to said motor casing, and a control valve mechanism carried by said axial member and having connection with said control chamber, said reservoir and the atmosphere and normally connecting said control chamber to the atmosphere, said reservoir having means for connecting it with a source of vacuum, said control valve mechanism being operative for disconnecting said control chamber from the atmosphere and connecting it to said reservoir to eifect a rapid evacuation of said control chamber.

References Cited in the file of this patent UNITED STATES PATENTS 1,457,665 Lucas June 5, 1923 2,745,383 Hupp May 15, 1956 2,818,835 Hupp Jan. 7, 1958 2,842,101 Price July 8, 1958 2,871,827 Price Feb. 3, 1959 2,880,704 Price Apr. 7, 1959 FOREIGN PATENTS 350,696 Germany Mar. 23, 1922