Patent Grant
8960073
The invention generally relates to a cylinder head for a compressor, such as of the type used in a utility vehicle.
Compressors for utility vehicles are generally mounted directly on the motor shaft and driven by the motor. Such compressors deliver compressed air for vehicle-internal compressed air systems, for example, for pneumatic brakes, ride level control systems and other systems.
A compressor of the general type under consideration is embodied as a reciprocating piston compressor (reciprocating compressor), and has a compressor casing and a cylinder head that closes the upper side of the compressor casing. A cylinder head gasket is provided between the cylinder head and a cylinder casing. One or more cylinders with pistons that are driven by the motor shaft are formed in the cylinder casing.
The compressor is pumping during delivery phases (on-load), while during rest phases and regeneration phases the compressor generally does not deliver any air (off-load). In many utility vehicles, the compressor is rigidly arranged on the motor shaft with the result that at least one piston continues to be moved up and down in the cylinder (reciprocating movement) even during the rest phases and regeneration phases. In order to keep the energy absorption of the piston compressor low, an idling circuit is generally set in which air is merely fed to and fro without being appreciably compressed. Generally, for this purpose, for compressors with only one cylinder, the cylinder space, the volume of which is reduced in the delivery phase, is connected via an air passage to an intake space arranged upstream or a connection space. For compressors with two or more cylinders with movements in opposite directions, cylinder spaces can be connected to one another via an air passage.
In order to close and open the air passage, a closure device, which is embodied, for example, as a lamella (leaf), is generally provided in the cylinder head. In its unactuated position (on-load), the closure device closes the air passage, with the result that the compressor can deliver air. In its actuated position (off-load), the closure device opens the air passage, with the result that the compressor runs in the idling mode.
The closure device is in turn moved between its actuated position (off-load) and unactuated position (on-load) by a pneumatic control device. For this purpose, the control device receives a pneumatic input signal, generally from a governor. The pneumatic control device generally has a control cylinder that runs in the cylinder head, for example, in a transverse direction, and in which a control piston, on which compressed air coming from the governor acts, is adjustably guided. The cylinder head also includes a spring device. While the spring device is in an unactuated position (on-load), the piston is in a position of rest and the closure device is closed. When compressed air is applied by the governor, the control piston is actuated (off-load) in order to open the closure device.
The connection between the control piston and the closure device is generally brought about by a driver, which is attached in the piston and extends through a slot in the cylinder head into the cylinder space. The driver is loosely inserted into a suitable opening in the closure device, with the result that it drives the closure device during the to and fro movement of the piston.
During assembly, the control piston is inserted, generally together with the spring device, into the control cylinder. The driver is pressed or screwed into the piston through the slot, with the result that it projects downwardly to the lower side through the slot. The closure device can then be hooked by its hole into the driver from the underside of the cylinder head.
Such an assembly, however, does not provide for easy disassembly. This is because the driver, which is permanently connected to the control piston, prevents the control piston from being pulled out of the control cylinder. Thus, removal of the driver from the control cylinder often requires destroying the control piston.
Furthermore, although reliable operation and reliable actuation of the closure device is generally possible, the return of the closure device to its unactuated position (on-load) for the loading of the compressor by the spring device can be problematic. According to Hooke's Law, the force applied by the spring device increases continuously when it is moved by the piston. During the return, the force applied by the spring device in turn decreases linearly, with the result that it becomes ever smaller at the end of the movement during which the closure device is intended to completely close the compressed air passage. In this context, although the spring device can be somewhat prestressed in its unactuated position (on-load), with the result that the spring device still has a residual force for closing the closure device at the end of the movement, the force is still smallest in this part of the movement. For this purpose, compressed air assistance of the spring device can be advantageous. In such a configuration, both compressed air and the spring device act on the piston during the return of the piston. Compressed air can be fed to the piston via a gap, but there can be air leakage for such configurations.
Generally speaking, it is an object of the present invention to provide a cylinder head having a driver for coupling a control piston to a closure device, where the closure device closes a compressed air passage in an unactuated position (on-load) and clears the compressed air passage in an actuated position (off-load).
The driver can be held firmly in the closure device and can be grasped by the control piston and entrained during the to and fro movement thereof. The driver can therefore be inserted loosely, into the control piston.
According to one embodiment, the control piston has a circumferential groove in which the driver is loosely held.
According to another embodiment, the driver is positively locked in the closure device. In some embodiments, the driver can be a rivet or rivet pin.
According to yet another embodiment, the driver can be disconnected from the control piston by pulling out in a removal direction, where the removal direction is different from the movement direction of the control piston.
According to a further embodiment, the closure device is pivotably coupled to a joint, where the closure device can be released from the joint in the removal direction.
According to another embodiment of the present invention, a pocket pivotably holds the closure device. The pocket can be formed on the underside of the cylinder head, and can define the pivoting travel of the closure device. The pneumatic control device can be provided above the pocket in the cylinder head. In this context, the cylinder head can be a bearing face for bearing against a cylinder casing, where the bearing face surrounds the pocket.
According to a further embodiment, a wall region of the cylinder head is formed between the pocket and the control cylinder, where a gap through which the driver projects is formed in the wall region, and where the driver can be moved in the gap during the movement of the control piston.
According to yet another embodiment, the control piston has a piston face and an opposing piston face that lies opposite the piston face. In addition, the control cylinder can have a control space for applying compressed air to the piston face of the control piston in order to actuate the control piston, and a piston space for applying compressed air to the opposing piston face. The control space can have a compressed air connection for feeding in compressed air in order to apply compressed air to the piston face, and for outputting compressed air in order to reset the control piston into the unactuated position (on-load). In addition, when the compressed air is applied, the opposing piston face can assist the spring device in moving the control piston into the unactuated position (on-load), thereby moving the closure device to a closed state. Furthermore, in at least an end part of the closing movement of the closure device, the opposing piston face can be connected to the gap such that compressed air can be applied to the opposing piston face.
According to another embodiment, the gap can have an enlarged width in certain regions in order to enlarge the passage area for compressed air in the final part of the closing movement of the closure device.
According to a still further embodiment, a free space can be formed in the closure device, where the free space can bear against the gap in the final part of the closing movement in order to permit compressed air to pass through. As a result, the operation of the compressor can be improved. The gap through which the driver projects can be embodied according to the invention in a selective fashion such that the air through-flow is increased in order to improve the resetting of the control piston during its final movement. For this purpose, the gap can be widened in certain regions. The driver therefore does not close the gap entirely at the end of its reset. Furthermore, the feeding in of compressed air for assisting the closing movement is improved.
Also, the free space can bear, in the final part of the movement of the closure device, against the gap, with the result that a significant increase in the passage of air, and therefore assistance of the spring device, is selectively brought about. Moreover, when the closure device is in other positions, the free space does not present problems because it does not bear against the gap nor is it aligned with the gap.
In accordance with exemplary embodiments of the invention, the cylinder head can be manufactured by inserting the control piston into the control cylinder to form the pneumatic control device, providing the closure device to which the driver is permanently attached, and inserting the closure device into a pocket in the cylinder head in the mounting direction, whereby the driver is guided through a gap between the pocket and the control cylinder and is engaged in a removable fashion in the control piston, and when the closure device is inserted in the mounting direction, an articulated holder for the closure device is formed in the pocket. Disassembly can be accomplished by reversing the order of these steps.
It will be appreciated that the inventive embodiments provide a number of advantages. For example, the driver can be easily connected to the control piston, and can also be easily removed from the control piston. Accordingly, system assembly is improved. Furthermore, disassembly is possible with a small amount of expenditure without destroying the control piston.
Still other objects and advantages of the present invention will in part be obvious and will in part be apparent from the specification.
The present invention accordingly comprises the features of construction, combination of elements, and arrangement of parts as well as the various steps and the relation of one or more of such steps with respect to each of the others, all as exemplified in the following disclosure, and the scope of the invention will be indicated in the claims.
For a fuller understanding of the invention, reference is had to the following description taken in connection with the accompanying drawings in which:
Referring now to the drawing figures,
Pocket 1b can be formed on underside 1a of cylinder head 1. Cylinder head 1 can be a bearing face for bearing against a cylinder casing, where the bearing face surrounds pocket 1b. That is, the portion of under side 1a exclusive of pocket 1b can be considered the bearing face. Joint pin 10 can be aligned, for example, in a flush fashion, with underside 1a. Pocket 1b therefore defines the pivoting travel of the pivotable closure device 8.
When closure device 8 is pivoted towards the left from the unactuated position (on-load) into its actuated position (off-load), it opens the compressed air passage 12, with the result that air can flow from a cylinder space formed in the cylinder casing and through compressed air passage 12 in order to permit an idling operation of the compressor. The compressor therefore operates with relatively low energy consumption without delivering compressed air in an idling operation.
Referring back to
Control piston 14 has a piston face 14a to which compressed air is applied in order to actuate control piston 14. For this purpose, control piston 14 rests, in the basic position or position of rest shown in
A wall region 17 of cylinder head 1 is formed between pocket 1b and control cylinder 16. A gap 24, through which a connection pin 26 projects, is formed in wall region 17. As shown in
Piston face 14a is located in a control space 30 which can be filled with compressed air and emptied through a compressed air connection 32, where compressed air connection 32 can be connected via corresponding valves. By applying compressed air via compressed air connection 32, control piston 14 can be moved to the left, counter to the effect of helical spring 20 of
Consequently, as shown in
As shown in
After the application of compressed air has ended, the venting via compressed air connection 32 can take place. Helical spring 20 therefore relaxes and presses the control piston 14 back (e.g., to the right in
The unactuated position (on-load) of closure device 8 is advantageously not defined by a stop in pocket 1b but rather by stop 18 of control piston 14.
For the purpose of assembling the arrangement shown in
As shown in
For the purpose of disassembly, closure device 8 together with driver 26 can be pulled out, in accordance with a reverse order, from joint pin 10 and control piston 14 in a removal direction counter to the mounting direction. Stop 18 and control piston 14 together with helical spring 20 can then be removed from control cylinder 16 counter to the axial direction.
It is to be understood that the present invention is suitable for all types of gas compressor designs, whatever the principle of operation in any individual case. The invention is also suitable for all types of gases. Only as an example, the air compressor using piston construction, such as the one normally used in automotive engineering, is mentioned as a special area of application.
It will be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained, and since certain changes may be made without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention that, as a matter of language, might be said to fall therebetween.
| Number | Name | Date | Kind |
|---|---|---|---|
| 1878326 | Ricardo | Sep 1932 | A |
| 2290858 | Brown | Jul 1942 | A |
| 4553907 | Heger et al. | Nov 1985 | A |
| 4685653 | Kaltenthaler et al. | Aug 1987 | A |
| Number | Date | Country | |
|---|---|---|---|
| 20130092019 A1 | Apr 2013 | US |
